flashrom.c

/*
 * This file is part of the flashrom project.
 *
 * Copyright (C) 2000 Silicon Integrated System Corporation
 * Copyright (C) 2004 Tyan Corp <yhlu@tyan.com>
 * Copyright (C) 2005-2008 coresystems GmbH
 * Copyright (C) 2008,2009 Carl-Daniel Hailfinger
 * Copyright (C) 2016 secunet Security Networks AG
 * (Written by Nico Huber <nico.huber@secunet.com> for secunet)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <stdio.h>
#include <sys/types.h>
#ifndef __LIBPAYLOAD__
#include <fcntl.h>
#include <sys/stat.h>
#endif
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <ctype.h>
#include <getopt.h>
#if HAVE_UTSNAME == 1
#include <sys/utsname.h>
#endif

#include "action_descriptor.h"
#include "flash.h"
#include "flashchips.h"
#include "layout.h"
#include "programmer.h"
#include "spi.h"
#include "chipdrivers.h"

const char flashrom_version[] = FLASHROM_VERSION;
const char *chip_to_probe = NULL;

/* Set if any erase/write operation is to be done. This will be used to
 * decide if final verification is needed. */
static int content_has_changed = 0;

/* error handling stuff */
static enum error_action access_denied_action = error_ignore;

int ignore_error(int err) {
	int rc = 0;

	switch(err) {
	case SPI_ACCESS_DENIED:
		if (access_denied_action == error_ignore)
			rc = 1;
		break;
	default:
		break;
	}

	return rc;
}

static enum programmer programmer = PROGRAMMER_INVALID;
static const char *programmer_param = NULL;

/*
 * Programmers supporting multiple buses can have differing size limits on
 * each bus. Store the limits for each bus in a common struct.
 */
struct decode_sizes max_rom_decode;

/* If nonzero, used as the start address of bottom-aligned flash. */
unsigned long flashbase;

/* Is writing allowed with this programmer? */
int programmer_may_write;

const struct programmer_entry programmer_table[] = {
#if CONFIG_INTERNAL == 1
	{
		.name			= "internal",
		.type			= OTHER,
		.devs.note		= NULL,
		.init			= internal_init,
		.map_flash_region	= physmap,
		.unmap_flash_region	= physunmap,
		.delay			= internal_delay,

		/*
		 * "Internal" implies in-system programming on a live system, so
		 * handle with paranoia to catch errors early. If something goes
		 * wrong then hopefully the system will still be recoverable.
		 */
		.paranoid		= 1,
	},
#endif

#if CONFIG_DUMMY == 1
	{
		.name			= "dummy",
		.type			= OTHER,
					/* FIXME */
		.devs.note		= "Dummy device, does nothing and logs all accesses\n",
		.init			= dummy_init,
		.map_flash_region	= dummy_map,
		.unmap_flash_region	= dummy_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_MEC1308 == 1
	{
		.name			= "mec1308",
		.type			= OTHER,
		.devs.note		= "Microchip MEC1308 Embedded Controller.\n",
		.init			= mec1308_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_NIC3COM == 1
	{
		.name			= "nic3com",
		.type			= PCI,
		.devs.dev		= nics_3com,
		.init			= nic3com_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_NICREALTEK == 1
	{
		/* This programmer works for Realtek RTL8139 and SMC 1211. */
		.name			= "nicrealtek",
		.type			= PCI,
		.devs.dev		= nics_realtek,
		.init			= nicrealtek_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_NICNATSEMI == 1
	{
		.name			= "nicnatsemi",
		.type			= PCI,
		.devs.dev		= nics_natsemi,
		.init			= nicnatsemi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_GFXNVIDIA == 1
	{
		.name			= "gfxnvidia",
		.type			= PCI,
		.devs.dev		= gfx_nvidia,
		.init			= gfxnvidia_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_RAIDEN_DEBUG_SPI == 1
	{
		.name			= "raiden_debug_spi",
		.type			= USB,
		.devs.dev		= devs_raiden,
		.init			= raiden_debug_spi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_DRKAISER == 1
	{
		.name			= "drkaiser",
		.type			= PCI,
		.devs.dev		= drkaiser_pcidev,
		.init			= drkaiser_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_SATASII == 1
	{
		.name			= "satasii",
		.type			= PCI,
		.devs.dev		= satas_sii,
		.init			= satasii_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_ATAHPT == 1
	{
		.name			= "atahpt",
		.type			= PCI,
		.devs.dev		= ata_hpt,
		.init			= atahpt_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_ATAVIA == 1
	{
		.name			= "atavia",
		.type			= PCI,
		.devs.dev		= ata_via,
		.init			= atavia_init,
		.map_flash_region	= atavia_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_ATAPROMISE == 1
	{
		.name			= "atapromise",
		.type			= PCI,
		.devs.dev		= ata_promise,
		.init			= atapromise_init,
		.map_flash_region	= atapromise_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_IT8212 == 1
	{
		.name			= "it8212",
		.type			= PCI,
		.devs.dev		= devs_it8212,
		.init			= it8212_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_FT2232_SPI == 1
	{
		.name			= "ft2232_spi",
		.type			= USB,
		.devs.dev		= devs_ft2232spi,
		.init			= ft2232_spi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_SERPROG == 1
	{
		.name			= "serprog",
		.type			= OTHER,
					/* FIXME */
		.devs.note		= "All programmer devices speaking the serprog protocol\n",
		.init			= serprog_init,
		.map_flash_region	= serprog_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= serprog_delay,
	},
#endif

#if CONFIG_BUSPIRATE_SPI == 1
	{
		.name			= "buspirate_spi",
		.type			= OTHER,
					/* FIXME */
		.devs.note		= "Dangerous Prototypes Bus Pirate\n",
		.init			= buspirate_spi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_DEDIPROG == 1
	{
		.name			= "dediprog",
		.type			= USB,
		.devs.dev		= devs_dediprog,
		.init			= dediprog_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_DEVELOPERBOX_SPI == 1
	{
		.name			= "developerbox",
		.type			= USB,
		.devs.dev		= devs_developerbox_spi,
		.init			= developerbox_spi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_ENE_LPC == 1
	{
		.name			= "ene_lpc",
		.type			= OTHER,
		.devs.note		= "ENE LPC interface keyboard controller\n",
		.init			= ene_lpc_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_RAYER_SPI == 1
	{
		.name			= "rayer_spi",
		.type			= OTHER,
					/* FIXME */
		.devs.note		= "RayeR parallel port programmer\n",
		.init			= rayer_spi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_PONY_SPI == 1
	{
		.name			= "pony_spi",
		.type			= OTHER,
					/* FIXME */
		.devs.note		= "Programmers compatible with SI-Prog, serbang or AJAWe\n",
		.init			= pony_spi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_NICINTEL == 1
	{
		.name			= "nicintel",
		.type			= PCI,
		.devs.dev		= nics_intel,
		.init			= nicintel_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_NICINTEL_SPI == 1
	{
		.name			= "nicintel_spi",
		.type			= PCI,
		.devs.dev		= nics_intel_spi,
		.init			= nicintel_spi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_NICINTEL_EEPROM == 1
	{
		.name			= "nicintel_eeprom",
		.type			= PCI,
		.devs.dev		= nics_intel_ee,
		.init			= nicintel_ee_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_OGP_SPI == 1
	{
		.name			= "ogp_spi",
		.type			= PCI,
		.devs.dev		= ogp_spi,
		.init			= ogp_spi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_SATAMV == 1
	{
		.name			= "satamv",
		.type			= PCI,
		.devs.dev		= satas_mv,
		.init			= satamv_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_LINUX_MTD == 1
	{
		.name			= "linux_mtd",
		.type			= OTHER,
		.devs.note		= "Device files /dev/mtd*\n",
		.init			= linux_mtd_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_LINUX_SPI == 1
	{
		.name			= "linux_spi",
		.type			= OTHER,
		.devs.note		= "Device files /dev/spidev*.*\n",
		.init			= linux_spi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_LSPCON_I2C_SPI == 1
	{
		.name			= "lspcon_i2c_spi",
		.type			= OTHER,
		.devs.note		= "Device files /dev/i2c-*.\n",
		.init			= lspcon_i2c_spi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_REALTEK_MST_I2C_SPI == 1
	{
		.name			= "realtek_mst_i2c_spi",
		.type			= OTHER,
		.devs.note		= "Device files /dev/i2c-*.\n",
		.init			= realtek_mst_i2c_spi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_USBBLASTER_SPI == 1
	{
		.name			= "usbblaster_spi",
		.type			= USB,
		.devs.dev		= devs_usbblasterspi,
		.init			= usbblaster_spi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_MSTARDDC_SPI == 1
	{
		.name			= "mstarddc_spi",
		.type			= OTHER,
		.devs.note		= "MSTAR DDC devices addressable via /dev/i2c-* on Linux.\n",
		.init			= mstarddc_spi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_PICKIT2_SPI == 1
	{
		.name			= "pickit2_spi",
		.type			= USB,
		.devs.dev		= devs_pickit2_spi,
		.init			= pickit2_spi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_CH341A_SPI == 1
	{
		.name			= "ch341a_spi",
		.type			= USB,
		.devs.dev		= devs_ch341a_spi,
		.init			= ch341a_spi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= ch341a_spi_delay,
	},
#endif

#if CONFIG_DIGILENT_SPI == 1
	{
		.name			= "digilent_spi",
		.type			= USB,
		.devs.dev		= devs_digilent_spi,
		.init			= digilent_spi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_JLINK_SPI == 1
	{
		.name			= "jlink_spi",
		.type			= OTHER,
		.init			= jlink_spi_init,
		.devs.note		= "SEGGER J-Link and compatible devices\n",
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_NI845X_SPI == 1
	{
		.name			= "ni845x_spi",
		.type			= OTHER, // choose other because NI-845x uses own USB implementation
		.devs.note		= "National Instruments USB-845x\n",
		.init			= ni845x_spi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_STLINKV3_SPI == 1
	{
		.name			= "stlinkv3_spi",
		.type			= USB,
		.devs.dev		= devs_stlinkv3_spi,
		.init			= stlinkv3_spi_init,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_GOOGLE_EC == 1
	{
		.name			= "google_ec",
		.type			= OTHER,
		.devs.note		= "Google EC.\n",
		.init			= cros_ec_probe_dev,
		.map_flash_region	= fallback_map,
		.unmap_flash_region	= fallback_unmap,
		.delay			= internal_delay,
	},
#endif

#if CONFIG_CROS_ALIAS == 1
	{
		.name			= "ec",
		.type			= OTHER,
		.devs.note		= "Google EC alias mechanism.\n",
		.init			= cros_ec_alias_init,
		.map_flash_region	= physmap, /* TODO(b/171934191) */
		.unmap_flash_region	= physunmap, /* TODO(b/171934191) */
		.delay			= internal_delay,

		/*
		 * "ec" implies in-system programming on a live system, so
		 * handle with paranoia to catch errors early. If something goes
		 * wrong then hopefully the system will still be recoverable.
		 */
		.paranoid		= 1,
	},

	{
		.name			= "host",
		.type			= OTHER,
		.devs.note		= "Google host alias mechanism.\n",
		.init			= cros_host_alias_init,
		.map_flash_region	= physmap,
		.unmap_flash_region	= physunmap,
		.delay			= internal_delay,

		/*
		 * "Internal" implies in-system programming on a live system, so
		 * handle with paranoia to catch errors early. If something goes
		 * wrong then hopefully the system will still be recoverable.
		 */
		.paranoid		= 1,
	},
#endif

	{0}, /* This entry corresponds to PROGRAMMER_INVALID. */
};

#define SHUTDOWN_MAXFN 32
static int shutdown_fn_count = 0;
/** @private */
static struct shutdown_func_data {
	int (*func) (void *data);
	void *data;
} shutdown_fn[SHUTDOWN_MAXFN];
/* Initialize to 0 to make sure nobody registers a shutdown function before
 * programmer init.
 */
static int may_register_shutdown = 0;

static int check_block_eraser(const struct flashctx *flash, int k, int log);

/* Register a function to be executed on programmer shutdown.
 * The advantage over atexit() is that you can supply a void pointer which will
 * be used as parameter to the registered function upon programmer shutdown.
 * This pointer can point to arbitrary data used by said function, e.g. undo
 * information for GPIO settings etc. If unneeded, set data=NULL.
 * Please note that the first (void *data) belongs to the function signature of
 * the function passed as first parameter.
 */
int register_shutdown(int (*function) (void *data), void *data)
{
	if (shutdown_fn_count >= SHUTDOWN_MAXFN) {
		msg_perr("Tried to register more than %i shutdown functions.\n",
			 SHUTDOWN_MAXFN);
		return 1;
	}
	if (!may_register_shutdown) {
		msg_perr("Tried to register a shutdown function before "
			 "programmer init.\n");
		return 1;
	}
	shutdown_fn[shutdown_fn_count].func = function;
	shutdown_fn[shutdown_fn_count].data = data;
	shutdown_fn_count++;

	return 0;
}

int register_chip_restore(chip_restore_fn_cb_t func,
			  struct flashctx *flash, uint8_t status)
{
	if (flash->chip_restore_fn_count >= MAX_CHIP_RESTORE_FUNCTIONS) {
		msg_perr("Tried to register more than %i chip restore"
		         " functions.\n", MAX_CHIP_RESTORE_FUNCTIONS);
		return 1;
	}
	flash->chip_restore_fn[flash->chip_restore_fn_count].func = func;
	flash->chip_restore_fn[flash->chip_restore_fn_count].status = status;
	flash->chip_restore_fn_count++;

	return 0;
}

static int deregister_chip_restore(struct flashctx *flash)
{
	int rc = 0;

	while (flash->chip_restore_fn_count > 0) {
		int i = --flash->chip_restore_fn_count;
		rc |= flash->chip_restore_fn[i].func(
			flash, flash->chip_restore_fn[i].status);
	}

	return rc;
}

int programmer_init(enum programmer prog, const char *param)
{
	int ret;

	if (prog >= PROGRAMMER_INVALID) {
		msg_perr("Invalid programmer specified!\n");
		return -1;
	}
	programmer = prog;
	/* Initialize all programmer specific data. */
	/* Default to unlimited decode sizes. */
	max_rom_decode = (const struct decode_sizes) {
		.parallel	= 0xffffffff,
		.lpc		= 0xffffffff,
		.fwh		= 0xffffffff,
		.spi		= 0xffffffff,
	};
	/* Default to top aligned flash at 4 GB. */
	flashbase = 0;
	/* Registering shutdown functions is now allowed. */
	may_register_shutdown = 1;
	/* Default to allowing writes. Broken programmers set this to 0. */
	programmer_may_write = 1;

	programmer_param = param;
	msg_pdbg("Initializing %s programmer\n", programmer_table[programmer].name);
	ret = programmer_table[programmer].init();
	if (programmer_param && strlen(programmer_param)) {
		if (ret != 0) {
			/* It is quite possible that any unhandled programmer parameter would have been valid,
			 * but an error in actual programmer init happened before the parameter was evaluated.
			 */
			msg_pwarn("Unhandled programmer parameters (possibly due to another failure): %s\n",
				  programmer_param);
		} else {
			/* Actual programmer init was successful, but the user specified an invalid or unusable
			 * (for the current programmer configuration) parameter.
			 */
			msg_perr("Unhandled programmer parameters: %s\n", programmer_param);
			msg_perr("Aborting.\n");
			ret = ERROR_FATAL;
		}
	}
	return ret;
}

/** Calls registered shutdown functions and resets internal programmer-related variables.
 * Calling it is safe even without previous initialization, but further interactions with programmer support
 * require a call to programmer_init() (afterwards).
 *
 * @return The OR-ed result values of all shutdown functions (i.e. 0 on success). */
int programmer_shutdown(void)
{
	int ret = 0;

	/* Registering shutdown functions is no longer allowed. */
	may_register_shutdown = 0;
	while (shutdown_fn_count > 0) {
		int i = --shutdown_fn_count;
		ret |= shutdown_fn[i].func(shutdown_fn[i].data);
	}

	programmer_param = NULL;
	registered_master_count = 0;

	return ret;
}

void *programmer_map_flash_region(const char *descr, uintptr_t phys_addr, size_t len)
{
	void *ret = programmer_table[programmer].map_flash_region(descr, phys_addr, len);
	return ret;
}

void programmer_unmap_flash_region(void *virt_addr, size_t len)
{
	programmer_table[programmer].unmap_flash_region(virt_addr, len);
	msg_gspew("%s: unmapped 0x%0*" PRIxPTR "\n", __func__, PRIxPTR_WIDTH, (uintptr_t)virt_addr);
}

void chip_writeb(const struct flashctx *flash, uint8_t val, chipaddr addr)
{
	flash->mst->par.chip_writeb(flash, val, addr);
}

void chip_writew(const struct flashctx *flash, uint16_t val, chipaddr addr)
{
	flash->mst->par.chip_writew(flash, val, addr);
}

void chip_writel(const struct flashctx *flash, uint32_t val, chipaddr addr)
{
	flash->mst->par.chip_writel(flash, val, addr);
}

void chip_writen(const struct flashctx *flash, const uint8_t *buf, chipaddr addr, size_t len)
{
	flash->mst->par.chip_writen(flash, buf, addr, len);
}

uint8_t chip_readb(const struct flashctx *flash, const chipaddr addr)
{
	return flash->mst->par.chip_readb(flash, addr);
}

uint16_t chip_readw(const struct flashctx *flash, const chipaddr addr)
{
	return flash->mst->par.chip_readw(flash, addr);
}

uint32_t chip_readl(const struct flashctx *flash, const chipaddr addr)
{
	return flash->mst->par.chip_readl(flash, addr);
}

void chip_readn(const struct flashctx *flash, uint8_t *buf, chipaddr addr,
		size_t len)
{
	flash->mst->par.chip_readn(flash, buf, addr, len);
}

void programmer_delay(unsigned int usecs)
{
	if (usecs > 0)
		programmer_table[programmer].delay(usecs);
}

int read_memmapped(struct flashctx *flash, uint8_t *buf, unsigned int start,
		   int unsigned len)
{
	chip_readn(flash, buf, flash->virtual_memory + start, len);

	return 0;
}

/* This is a somewhat hacked function similar in some ways to strtok().
 * It will look for needle with a subsequent '=' in haystack, return a copy of
 * needle and remove everything from the first occurrence of needle to the next
 * delimiter from haystack.
 */
char *extract_param(const char *const *haystack, const char *needle, const char *delim)
{
	char *param_pos, *opt_pos, *rest;
	char *opt = NULL;
	int optlen;
	int needlelen;

	needlelen = strlen(needle);
	if (!needlelen) {
		msg_gerr("%s: empty needle! Please report a bug at "
			 "flashrom@flashrom.org\n", __func__);
		return NULL;
	}
	/* No programmer parameters given. */
	if (*haystack == NULL)
		return NULL;
	param_pos = strstr(*haystack, needle);
	do {
		if (!param_pos)
			return NULL;
		/* Needle followed by '='? */
		if (param_pos[needlelen] == '=') {
			/* Beginning of the string? */
			if (param_pos == *haystack)
				break;
			/* After a delimiter? */
			if (strchr(delim, *(param_pos - 1)))
				break;
		}
		/* Continue searching. */
		param_pos++;
		param_pos = strstr(param_pos, needle);
	} while (1);

	if (param_pos) {
		/* Get the string after needle and '='. */
		opt_pos = param_pos + needlelen + 1;
		optlen = strcspn(opt_pos, delim);
		/* Return an empty string if the parameter was empty. */
		opt = malloc(optlen + 1);
		if (!opt) {
			msg_gerr("Out of memory!\n");
			exit(1);
		}
		strncpy(opt, opt_pos, optlen);
		opt[optlen] = '\0';
		rest = opt_pos + optlen;
		/* Skip all delimiters after the current parameter. */
		rest += strspn(rest, delim);
		memmove(param_pos, rest, strlen(rest) + 1);
		/* We could shrink haystack, but the effort is not worth it. */
	}

	return opt;
}

char *extract_programmer_param(const char *param_name)
{
	return extract_param(&programmer_param, param_name, ",");
}

/* Returns the number of well-defined erasers for a chip. */
static unsigned int count_usable_erasers(const struct flashctx *flash)
{
	unsigned int usable_erasefunctions = 0;
	int k;
	for (k = 0; k < NUM_ERASEFUNCTIONS; k++) {
		if (!check_block_eraser(flash, k, 0))
			usable_erasefunctions++;
	}
	return usable_erasefunctions;
}

static int compare_range(const uint8_t *wantbuf, const uint8_t *havebuf, unsigned int start, unsigned int len)
{
	int ret = 0, failcount = 0;
	unsigned int i;
	for (i = 0; i < len; i++) {
		if (wantbuf[i] != havebuf[i]) {
			/* Only print the first failure. */
			if (!failcount++)
				msg_cerr("FAILED at 0x%08x! Expected=0x%02x, Found=0x%02x,",
					 start + i, wantbuf[i], havebuf[i]);
		}
	}
	if (failcount) {
		msg_cerr(" failed byte count from 0x%08x-0x%08x: 0x%x\n",
			 start, start + len - 1, failcount);
		ret = -1;
	}
	return ret;
}

/* start is an offset to the base address of the flash chip */
static int check_erased_range(struct flashctx *flash, unsigned int start, unsigned int len)
{
	int ret;
	uint8_t *cmpbuf = malloc(len);
	const uint8_t erased_value = ERASED_VALUE(flash);

	if (!cmpbuf) {
		msg_gerr("Could not allocate memory!\n");
		exit(1);
	}
	memset(cmpbuf, erased_value, len);
	ret = verify_range(flash, cmpbuf, start, len);
	free(cmpbuf);
	return ret;
}

/*
 * @cmpbuf	buffer to compare against, cmpbuf[0] is expected to match the
 *		flash content at location start
 * @start	offset to the base address of the flash chip
 * @len		length of the verified area
 * @return	0 for success, -1 for failure
 */
int verify_range(struct flashctx *flash, const uint8_t *cmpbuf, unsigned int start, unsigned int len)
{
	if (!len)
		return -1;

	if (!flash->chip->read) {
		msg_cerr("ERROR: flashrom has no read function for this flash chip.\n");
		return -1;
	}

	uint8_t *readbuf = malloc(len);
	if (!readbuf) {
		msg_gerr("Could not allocate memory!\n");
		return -1;
	}
	int ret = 0, failcount = 0;

	if (start + len > flash->chip->total_size * 1024) {
		msg_gerr("Error: %s called with start 0x%x + len 0x%x >"
			" total_size 0x%x\n", __func__, start, len,
			flash->chip->total_size * 1024);
		ret = -1;
		goto out_free;
	}
	msg_gdbg("%#06x..%#06x ", start, start + len -1);
	if (programmer_table[programmer].paranoid) {
		unsigned int i, chunksize;

		/* limit chunksize in order to catch errors early */
		for (i = 0, chunksize = 0; i < len; i += chunksize) {
			int tmp;

			chunksize = min(flash->chip->page_size, len - i);
			tmp = flash->chip->read(flash, readbuf + i, start + i, chunksize);
			if (tmp) {
				ret = tmp;
				if (ignore_error(tmp))
					continue;
				else
					goto out_free;
			}

			/*
			 * Check write access permission and do not compare chunks
			 * where flashrom does not have write access to the region.
			 */
			if (flash->chip->check_access) {
				tmp = flash->chip->check_access(flash, start + i, chunksize, 0);
				if (tmp && ignore_error(tmp))
					continue;
			}

			failcount = compare_range(cmpbuf + i, readbuf + i, start + i, chunksize);
			if (failcount)
				break;
		}
	} else {
		int tmp;

		/* read as much as we can to reduce transaction overhead */
		tmp = flash->chip->read(flash, readbuf, start, len);
		if (tmp && !ignore_error(tmp)) {
			ret = tmp;
			goto out_free;
		}

		failcount = compare_range(cmpbuf, readbuf, start, len);
	}

	if (failcount) {
		msg_cerr(" failed byte count from 0x%08x-0x%08x: 0x%x\n",
			 start, start + len - 1, failcount);
		ret = -1;
	}

out_free:
	free(readbuf);
	return ret;
}

/* Helper function for need_erase() that focuses on granularities of gran bytes. */
static int need_erase_gran_bytes(const uint8_t *have, const uint8_t *want, unsigned int len,
                                 unsigned int gran, const uint8_t erased_value)
{
	unsigned int i, j, limit;
	for (j = 0; j < len / gran; j++) {
		limit = min (gran, len - j * gran);
		/* Are 'have' and 'want' identical? */
		if (!memcmp(have + j * gran, want + j * gran, limit))
			continue;
		/* have needs to be in erased state. */
		for (i = 0; i < limit; i++)
			if (have[j * gran + i] != erased_value)
				return 1;
	}
	return 0;
}

/*
 * Check if the buffer @have can be programmed to the content of @want without
 * erasing. This is only possible if all chunks of size @gran are either kept
 * as-is or changed from an all-ones state to any other state.
 *
 * Warning: This function assumes that @have and @want point to naturally
 * aligned regions.
 *
 * @have        buffer with current content
 * @want        buffer with desired content
 * @len		length of the checked area
 * @gran	write granularity (enum, not count)
 * @return      0 if no erase is needed, 1 otherwise
 */
int need_erase(const uint8_t *have, const uint8_t *want, unsigned int len,
               enum write_granularity gran, const uint8_t erased_value)
{
	int result = 0;
	unsigned int i;

	switch (gran) {
	case write_gran_1bit:
		for (i = 0; i < len; i++)
			if ((have[i] & want[i]) != want[i]) {
				result = 1;
				break;
			}
		break;
	case write_gran_1byte:
		for (i = 0; i < len; i++)
			if ((have[i] != want[i]) && (have[i] != erased_value)) {
				result = 1;
				break;
			}
		break;
	case write_gran_128bytes:
		result = need_erase_gran_bytes(have, want, len, 128, erased_value);
		break;
	case write_gran_256bytes:
		result = need_erase_gran_bytes(have, want, len, 256, erased_value);
		break;
	case write_gran_264bytes:
		result = need_erase_gran_bytes(have, want, len, 264, erased_value);
		break;
	case write_gran_512bytes:
		result = need_erase_gran_bytes(have, want, len, 512, erased_value);
		break;
	case write_gran_528bytes:
		result = need_erase_gran_bytes(have, want, len, 528, erased_value);
		break;
	case write_gran_1024bytes:
		result = need_erase_gran_bytes(have, want, len, 1024, erased_value);
		break;
	case write_gran_1056bytes:
		result = need_erase_gran_bytes(have, want, len, 1056, erased_value);
		break;
	case write_gran_1byte_implicit_erase:
		/* Do not erase, handle content changes from anything->0xff by writing 0xff. */
		result = 0;
		break;
	default:
		msg_cerr("%s: Unsupported granularity! Please report a bug at "
			 "flashrom@flashrom.org\n", __func__);
	}
	return result;
}

/**
 * Check if the buffer @have needs to be programmed to get the content of @want.
 * If yes, return 1 and fill in first_start with the start address of the
 * write operation and first_len with the length of the first to-be-written
 * chunk. If not, return 0 and leave first_start and first_len undefined.
 *
 * Warning: This function assumes that @have and @want point to naturally
 * aligned regions.
 *
 * @have	buffer with current content
 * @want	buffer with desired content
 * @len		length of the checked area
 * @gran	write granularity (enum, not count)
 * @first_start	offset of the first byte which needs to be written (passed in
 *		value is increased by the offset of the first needed write
 *		relative to have/want or unchanged if no write is needed)
 * @return	length of the first contiguous area which needs to be written
 *		0 if no write is needed
 *
 * FIXME: This function needs a parameter which tells it about coalescing
 * in relation to the max write length of the programmer and the max write
 * length of the chip.
 */
static unsigned int get_next_write(const uint8_t *have, const uint8_t *want, unsigned int len,
			  unsigned int *first_start,
			  enum write_granularity gran)
{
	int need_write = 0;
	unsigned int rel_start = 0, first_len = 0;
	unsigned int i, limit, stride;

	switch (gran) {
	case write_gran_1bit:
	case write_gran_1byte:
	case write_gran_1byte_implicit_erase:
		stride = 1;
		break;
	case write_gran_128bytes:
		stride = 128;
		break;
	case write_gran_256bytes:
		stride = 256;
		break;
	case write_gran_264bytes:
		stride = 264;
		break;
	case write_gran_512bytes:
		stride = 512;
		break;
	case write_gran_528bytes:
		stride = 528;
		break;
	case write_gran_1024bytes:
		stride = 1024;
		break;
	case write_gran_1056bytes:
		stride = 1056;
		break;
	default:
		msg_cerr("%s: Unsupported granularity! Please report a bug at "
			 "flashrom@flashrom.org\n", __func__);
		/* Claim that no write was needed. A write with unknown
		 * granularity is too dangerous to try.
		 */
		return 0;
	}
	for (i = 0; i < len / stride; i++) {
		limit = min(stride, len - i * stride);
		/* Are 'have' and 'want' identical? */
		if (memcmp(have + i * stride, want + i * stride, limit)) {
			if (!need_write) {
				/* First location where have and want differ. */
				need_write = 1;
				rel_start = i * stride;
			}
		} else {
			if (need_write) {
				/* First location where have and want
				 * do not differ anymore.
				 */
				break;
			}
		}
	}
	if (need_write)
		first_len = min(i * stride - rel_start, len);
	*first_start += rel_start;
	return first_len;
}

/* Returns the number of busses commonly supported by the current programmer and flash chip where the latter
 * can not be completely accessed due to size/address limits of the programmer. */
unsigned int count_max_decode_exceedings(const struct flashctx *flash)
{
	unsigned int limitexceeded = 0;
	uint32_t size = flash->chip->total_size * 1024;
	enum chipbustype buses = flash->mst->buses_supported & flash->chip->bustype;

	if ((buses & BUS_PARALLEL) && (max_rom_decode.parallel < size)) {
		limitexceeded++;
		msg_pdbg("Chip size %u kB is bigger than supported "
			 "size %u kB of chipset/board/programmer "
			 "for %s interface, "
			 "probe/read/erase/write may fail. ", size / 1024,
			 max_rom_decode.parallel / 1024, "Parallel");
	}
	if ((buses & BUS_LPC) && (max_rom_decode.lpc < size)) {
		limitexceeded++;
		msg_pdbg("Chip size %u kB is bigger than supported "
			 "size %u kB of chipset/board/programmer "
			 "for %s interface, "
			 "probe/read/erase/write may fail. ", size / 1024,
			 max_rom_decode.lpc / 1024, "LPC");
	}
	if ((buses & BUS_FWH) && (max_rom_decode.fwh < size)) {
		limitexceeded++;
		msg_pdbg("Chip size %u kB is bigger than supported "
			 "size %u kB of chipset/board/programmer "
			 "for %s interface, "
			 "probe/read/erase/write may fail. ", size / 1024,
			 max_rom_decode.fwh / 1024, "FWH");
	}
	if ((buses & BUS_SPI) && (max_rom_decode.spi < size)) {
		limitexceeded++;
		msg_pdbg("Chip size %u kB is bigger than supported "
			 "size %u kB of chipset/board/programmer "
			 "for %s interface, "
			 "probe/read/erase/write may fail. ", size / 1024,
			 max_rom_decode.spi / 1024, "SPI");
	}
	return limitexceeded;
}

void unmap_flash(struct flashctx *flash)
{
	if (flash->virtual_registers != (chipaddr)ERROR_PTR) {
		programmer_unmap_flash_region((void *)flash->virtual_registers, flash->chip->total_size * 1024);
		flash->physical_registers = 0;
		flash->virtual_registers = (chipaddr)ERROR_PTR;
	}

	if (flash->virtual_memory != (chipaddr)ERROR_PTR) {
		programmer_unmap_flash_region((void *)flash->virtual_memory, flash->chip->total_size * 1024);
		flash->physical_memory = 0;
		flash->virtual_memory = (chipaddr)ERROR_PTR;
	}
}

int map_flash(struct flashctx *flash)
{
	/* Init pointers to the fail-safe state to distinguish them later from legit values. */
	flash->virtual_memory = (chipaddr)ERROR_PTR;
	flash->virtual_registers = (chipaddr)ERROR_PTR;

	/* FIXME: This avoids mapping (and unmapping) of flash chip definitions with size 0.
	 * These are used for various probing-related hacks that would not map successfully anyway and should be
	 * removed ASAP. */
	if (flash->chip->total_size == 0)
		return 0;

	const chipsize_t size = flash->chip->total_size * 1024;
	uintptr_t base = flashbase ? flashbase : (0xffffffff - size + 1);
	void *addr = programmer_map_flash_region(flash->chip->name, base, size);
	if (addr == ERROR_PTR) {
		msg_perr("Could not map flash chip %s at 0x%0*" PRIxPTR ".\n",
			 flash->chip->name, PRIxPTR_WIDTH, base);
		return 1;
	}
	flash->physical_memory = base;
	flash->virtual_memory = (chipaddr)addr;

	/* FIXME: Special function registers normally live 4 MByte below flash space, but it might be somewhere
	 * completely different on some chips and programmers, or not mappable at all.
	 * Ignore these problems for now and always report success. */
	if (flash->chip->feature_bits & FEATURE_REGISTERMAP) {
		base = 0xffffffff - size - 0x400000 + 1;
		addr = programmer_map_flash_region("flash chip registers", base, size);
		if (addr == ERROR_PTR) {
			msg_pdbg2("Could not map flash chip registers %s at 0x%0*" PRIxPTR ".\n",
				 flash->chip->name, PRIxPTR_WIDTH, base);
			return 0;
		}
		flash->physical_registers = base;
		flash->virtual_registers = (chipaddr)addr;
	}
	return 0;
}

/*
 * Return a string corresponding to the bustype parameter.
 * Memory is obtained with malloc() and must be freed with free() by the caller.
 */
char *flashbuses_to_text(enum chipbustype bustype)
{
	char *ret = calloc(1, 1);
	/*
	 * FIXME: Once all chipsets and flash chips have been updated, NONSPI
	 * will cease to exist and should be eliminated here as well.
	 */
	if (bustype == BUS_NONSPI) {
		ret = strcat_realloc(ret, "Non-SPI, ");
	} else {
		if (bustype & BUS_PARALLEL)
			ret = strcat_realloc(ret, "Parallel, ");
		if (bustype & BUS_LPC)
			ret = strcat_realloc(ret, "LPC, ");
		if (bustype & BUS_FWH)
			ret = strcat_realloc(ret, "FWH, ");
		if (bustype & BUS_SPI)
			ret = strcat_realloc(ret, "SPI, ");
		if (bustype & BUS_PROG)
			ret = strcat_realloc(ret, "Programmer-specific, ");
		if (bustype == BUS_NONE)
			ret = strcat_realloc(ret, "None, ");
	}
	/* Kill last comma. */
	ret[strlen(ret) - 2] = '\0';
	ret = realloc(ret, strlen(ret) + 1);
	return ret;
}

int probe_flash(struct registered_master *mst, int startchip, struct flashctx *flash, int force)
{
	const struct flashchip *chip;
	enum chipbustype buses_common;
	char *tmp;

	for (chip = flashchips + startchip; chip && chip->name; chip++) {
		if (chip_to_probe && strcmp(chip->name, chip_to_probe) != 0)
			continue;
		buses_common = mst->buses_supported & chip->bustype;
		if (!buses_common)
			continue;
		/* Only probe for SPI25 chips by default. */
		if (chip->bustype == BUS_SPI && !chip_to_probe && chip->spi_cmd_set != SPI25)
			continue;
		msg_gdbg("Probing for %s %s, %d kB: ", chip->vendor, chip->name, chip->total_size);
		if (!chip->probe && !force) {
			msg_gdbg("failed! flashrom has no probe function for this flash chip.\n");
			continue;
		}

		/* Start filling in the dynamic data. */
		flash->chip = calloc(1, sizeof(struct flashchip));
		if (!flash->chip) {
			msg_gerr("Out of memory!\n");
			exit(1);
		}
		memcpy(flash->chip, chip, sizeof(struct flashchip));
		flash->mst = mst;

		if (map_flash(flash) != 0)
			goto notfound;

		/* We handle a forced match like a real match, we just avoid probing. Note that probe_flash()
		 * is only called with force=1 after normal probing failed.
		 */
		if (force)
			break;

		if (flash->chip->probe(flash) != 1)
			goto notfound;

		/* If this is the first chip found, accept it.
		 * If this is not the first chip found, accept it only if it is
		 * a non-generic match. SFDP and CFI are generic matches.
		 * startchip==0 means this call to probe_flash() is the first
		 * one for this programmer interface (master) and thus no other chip has
		 * been found on this interface.
		 */
		if (startchip == 0 && flash->chip->model_id == SFDP_DEVICE_ID) {
			msg_cinfo("===\n"
				  "SFDP has autodetected a flash chip which is "
				  "not natively supported by flashrom yet.\n");
			if (count_usable_erasers(flash) == 0)
				msg_cinfo("The standard operations read and "
					  "verify should work, but to support "
					  "erase, write and all other "
					  "possible features");
			else
				msg_cinfo("All standard operations (read, "
					  "verify, erase and write) should "
					  "work, but to support all possible "
					  "features");

			msg_cinfo(" we need to add them manually.\n"
				  "You can help us by mailing us the output of the following command to "
				  "flashrom@flashrom.org:\n"
				  "'flashrom -VV [plus the -p/--programmer parameter]'\n"
				  "Thanks for your help!\n"
				  "===\n");
		}

		/* First flash chip detected on this bus. */
		if (startchip == 0)
			break;
		/* Not the first flash chip detected on this bus, but not a generic match either. */
		if ((flash->chip->model_id != GENERIC_DEVICE_ID) && (flash->chip->model_id != SFDP_DEVICE_ID))
			break;
		/* Not the first flash chip detected on this bus, and it's just a generic match. Ignore it. */
notfound:
		unmap_flash(flash);
		free(flash->chip);
		flash->chip = NULL;
	}

	if (!chip || !chip->name)
		return -1;


	tmp = flashbuses_to_text(chip->bustype);
	msg_cinfo("%s %s flash chip \"%s\" (%d kB, %s) ", force ? "Assuming" : "Found",
		  flash->chip->vendor, flash->chip->name, flash->chip->total_size, tmp);
	free(tmp);
#if CONFIG_INTERNAL == 1
	if (programmer_table[programmer].map_flash_region == physmap)
		msg_cinfo("mapped at physical address 0x%0*" PRIxPTR ".\n",
			  PRIxPTR_WIDTH, flash->physical_memory);
	else
#endif
		msg_cinfo("on %s.\n", programmer_table[programmer].name);

	/* Flash registers may more likely not be mapped if the chip was forced.
	 * Lock info may be stored in registers, so avoid lock info printing. */
	if (!force)
		if (flash->chip->printlock)
			flash->chip->printlock(flash);

	/* Get out of the way for later runs. */
	unmap_flash(flash);

	/* Return position of matching chip. */
	return chip - flashchips;
}

int read_buf_from_file(unsigned char *buf, unsigned long size,
		       const char *filename)
{
	unsigned long numbytes;
	FILE *image;
	struct stat image_stat;

	if (!strncmp(filename, "-", sizeof("-")))
		image = fdopen(STDIN_FILENO, "rb");
	else
		image = fopen(filename, "rb");
	if (image == NULL) {
		perror(filename);
		return 1;
	}
	if (fstat(fileno(image), &image_stat) != 0) {
		perror(filename);
		fclose(image);
		return 1;
	}
	if ((image_stat.st_size != size) &&
	    (strncmp(filename, "-", sizeof("-")))) {
		msg_gerr("Error: Image size doesn't match: stat %jd bytes, "
			 "wanted %ld!\n", (intmax_t)image_stat.st_size, size);
		fclose(image);
		return 1;
	}
	numbytes = fread(buf, 1, size, image);
	if (fclose(image)) {
		perror(filename);
		return 1;
	}
	if (numbytes != size) {
		msg_gerr("Error: Failed to read complete file. Got %ld bytes, "
			 "wanted %ld!\n", numbytes, size);
		return 1;
	}
	return 0;
}

int write_buf_to_file(const unsigned char *buf, unsigned long size, const char *filename)
{
	unsigned long numbytes;
	FILE *image;

	if (!filename) {
		msg_gerr("No filename specified.\n");
		return 1;
	}
	if (!strncmp(filename, "-", sizeof("-")))
		image = fdopen(STDOUT_FILENO, "wb");
	else
		image = fopen(filename, "wb");
	if (image == NULL) {
		perror(filename);
		return 1;
	}

	numbytes = fwrite(buf, 1, size, image);
	fclose(image);
	if (numbytes != size) {
		msg_gerr("Error: file %s could not be written completely.\n", filename);
		return 1;
	}
	return 0;
}

/*
 * read_flash - wrapper for flash->read() with additional high-level policy
 *
 * @flash	flash chip
 * @buf		buffer to store data in
 * @start	start address
 * @len		number of bytes to read
 *
 * This wrapper simplifies most cases when the flash chip needs to be read
 * since policy decisions such as non-fatal error handling is centralized.
 */
int read_flash(struct flashctx *flash, uint8_t *buf,
		unsigned int start, unsigned int len)
{
	int ret;

	if (!flash || !flash->chip->read)
		return -1;

	msg_cdbg("%#06x-%#06x:R ", start, start + len - 1);

	ret = flash->chip->read(flash, buf, start, len);
	if (ret) {
		if (ignore_error(ret)) {
			msg_gdbg("ignoring error when reading 0x%x-0x%x\n",
					start, start + len - 1);
			ret = 0;
		} else {
			msg_gdbg("failed to read 0x%x-0x%x\n",
					start, start + len - 1);
		}
	}

	return ret;
}

/*
 * write_flash - wrapper for flash->write() with additional high-level policy
 *
 * @flash	flash chip
 * @buf		buffer to write to flash
 * @start	start address in flash
 * @len		number of bytes to write
 *
 * TODO: Look up regions that are write-protected and avoid attempt to write
 * to them at all.
 */
int write_flash(struct flashctx *flash, uint8_t *buf,
		unsigned int start, unsigned int len)
{
	if (!flash || !flash->chip->write)
		return -1;

	return flash->chip->write(flash, buf, start, len);
}

int read_flash_to_file(struct flashctx *flash, const char *filename)
{
	unsigned long size = flash->chip->total_size * 1024;
	unsigned char *buf = calloc(size, sizeof(unsigned char));
	int ret = 0;

	msg_cinfo("Reading flash... ");
	if (!buf) {
		msg_gerr("Memory allocation failed!\n");
		msg_cinfo("FAILED.\n");
		return 1;
	}

	/* To support partial read, fill buffer to all 0xFF at beginning to make
	 * debug easier. */
	memset(buf, ERASED_VALUE(flash), size);

	if (!flash->chip->read) {
		msg_cerr("No read function available for this flash chip.\n");
		ret = 1;
		goto out_free;
	}

	/* First try to handle partial read case, rather than read the whole
	 * flash, which is slow. */
	ret = handle_partial_read(flash, buf, read_flash, 1);
	if (ret < 0) {
		msg_cerr("Partial read operation failed!\n");
		ret = 1;
		goto out_free;
	} else if (ret > 0) {
		int num_regions = get_num_include_args();

		if (ret != num_regions) {
			msg_cerr("Requested %d regions, but only read %d\n",
					num_regions, ret);
			ret = 1;
			goto out_free;
		}

		ret = 0;
	} else {
		if (read_flash(flash, buf, 0, size)) {
			msg_cerr("Read operation failed!\n");
			ret = 1;
			goto out_free;
		}
	}

	if (filename)
		ret = write_buf_to_file(buf, size, filename);

out_free:
	free(buf);
	if (ret)
		msg_cerr("FAILED.");
	else
		msg_cdbg("done.");
	return ret;
}

/* Even if an error is found, the function will keep going and check the rest. */
static int selfcheck_eraseblocks(const struct flashchip *chip)
{
	int i, j, k;
	int ret = 0;

	for (k = 0; k < NUM_ERASEFUNCTIONS; k++) {
		unsigned int done = 0;
		struct block_eraser eraser = chip->block_erasers[k];

		for (i = 0; i < NUM_ERASEREGIONS; i++) {
			/* Blocks with zero size are bugs in flashchips.c. */
			if (eraser.eraseblocks[i].count &&
			    !eraser.eraseblocks[i].size) {
				msg_gerr("ERROR: Flash chip %s erase function "
					"%i region %i has size 0. Please report"
					" a bug at flashrom@flashrom.org\n",
					chip->name, k, i);
				ret = 1;
			}
			/* Blocks with zero count are bugs in flashchips.c. */
			if (!eraser.eraseblocks[i].count &&
			    eraser.eraseblocks[i].size) {
				msg_gerr("ERROR: Flash chip %s erase function "
					"%i region %i has count 0. Please report"
					" a bug at flashrom@flashrom.org\n",
					chip->name, k, i);
				ret = 1;
			}
			done += eraser.eraseblocks[i].count *
				eraser.eraseblocks[i].size;
		}
		/* Empty eraseblock definition with erase function.  */
		if (!done && eraser.block_erase)
			msg_gspew("Strange: Empty eraseblock definition with "
				  "non-empty erase function. Not an error.\n");
		if (!done)
			continue;
		if (done != chip->total_size * 1024) {
			msg_gerr("ERROR: Flash chip %s erase function %i "
				"region walking resulted in 0x%06x bytes total,"
				" expected 0x%06x bytes. Please report a bug at"
				" flashrom@flashrom.org\n", chip->name, k,
				done, chip->total_size * 1024);
			ret = 1;
		}
		if (!eraser.block_erase)
			continue;
		/* Check if there are identical erase functions for different
		 * layouts. That would imply "magic" erase functions. The
		 * easiest way to check this is with function pointers.
		 */
		for (j = k + 1; j < NUM_ERASEFUNCTIONS; j++) {
			if (eraser.block_erase ==
			    chip->block_erasers[j].block_erase) {
				msg_gerr("ERROR: Flash chip %s erase function "
					"%i and %i are identical. Please report"
					" a bug at flashrom@flashrom.org\n",
					chip->name, k, j);
				ret = 1;
			}
		}
	}
	return ret;
}

static int check_block_eraser(const struct flashctx *flash, int k, int log)
{
	struct block_eraser eraser = flash->chip->block_erasers[k];

	if (!eraser.block_erase && !eraser.eraseblocks[0].count) {
		if (log)
			msg_cdbg("not defined. ");
		return 1;
	}
	if (!eraser.block_erase && eraser.eraseblocks[0].count) {
		if (log)
			msg_cdbg("eraseblock layout is known, but matching "
				 "block erase function is not implemented. ");
		return 1;
	}
	if (eraser.block_erase && !eraser.eraseblocks[0].count) {
		if (log)
			msg_cdbg("block erase function found, but "
				 "eraseblock layout is not defined. ");
		return 1;
	}
	// TODO: Once erase functions are annotated with allowed buses, check that as well.
	return 0;
}

typedef int (*erasefn_t)(struct flashctx *, unsigned int addr, unsigned int len);
/**
 * @private
 *
 * For read-erase-write, `curcontents` and `newcontents` shall point
 * to buffers of the chip's size. Both are supposed to be prefilled
 * with at least the included layout regions of the current flash
 * contents (`curcontents`) and the data to be written to the flash
 * (`newcontents`).
 *
 * For erase, `curcontents` and `newcontents` shall be NULL-pointers.
 *
 * The `chipoff_t` values are used internally by `walk_by_layout()`.
 */
struct walk_info {
	uint8_t *curcontents;
	const uint8_t *newcontents;
	chipoff_t erase_start;
	chipoff_t erase_len;
};
typedef int (*per_blockfn_t)(struct flashctx *, struct walk_info *const, erasefn_t);

/*
 * Function to process processing units accumulated in the action descriptor.
 *
 * @flash         pointer to the flash context to operate on
 * @per_blockfn   helper function which can erase and program a section of the
 *                flash chip. It receives the flash context, offset and length
 *                of the area to erase/program, before and after contents (to
 *                decide what exactly needs to be erased and or programmed)
 *                and a pointer to the erase function which can operate on the
 *                proper granularity.
 * @descriptor    action descriptor including pointers to before and after
 *		  contents and an array of processing actions to take.
 *
 * Returns zero on success or an error code.
 */
static int walk_eraseregions(struct flashctx *flash,
			     const per_blockfn_t per_blockfn,
			     struct action_descriptor *descriptor)
{
	struct processing_unit *pu;
	int rc = 0;
	static int print_comma;

	for (pu = descriptor->processing_units; pu->num_blocks; pu++) {
		unsigned base = pu->offset;
		unsigned top = pu->offset + pu->block_size * pu->num_blocks;

		while (base < top) {

			if (print_comma)
				msg_cdbg(", ");
			else
				print_comma = 1;

			msg_cdbg("0x%06x-0x%06zx", base, base + pu->block_size - 1);

			struct walk_info info = {
				.curcontents = descriptor->oldcontents,
				.newcontents = descriptor->newcontents,
				.erase_start = base,
				.erase_len   = pu->block_size,
			};
			rc = per_blockfn(flash, &info,
					  flash->chip->block_erasers[pu->block_eraser_index].block_erase);

			if (rc) {
				if (ignore_error(rc))
					rc = 0;
				else
					return rc;
			}
			base += pu->block_size;
		}
	}
	msg_cdbg("\n");
	return rc;
}

static int erase_and_write_block_helper(struct flashctx *flash,
					struct walk_info *const info,
					erasefn_t erasefn)
{
	unsigned int starthere = 0, lenhere = 0;
	int ret = 0, skip = 1, writecount = 0;
	int block_was_erased = 0;
	enum write_granularity gran = flash->chip->gran;

	/*
	 * curcontents and newcontents are opaque to walk_eraseregions, and
	 * need to be adjusted here to keep the impression of proper
	 * abstraction
	 */

	info->curcontents += info->erase_start;

	info->newcontents += info->erase_start;

	msg_cdbg(":");
	if (need_erase(info->curcontents, info->newcontents, info->erase_len, gran, 0xff)) {
		content_has_changed |= 1;
		msg_cdbg(" E");
		ret = erasefn(flash, info->erase_start, info->erase_len);
		if (ret) {
			if (ret == SPI_ACCESS_DENIED)
				msg_cdbg(" DENIED");
			else
				msg_cerr(" ERASE_FAILED\n");
			return ret;
		}

		if (programmer_table[programmer].paranoid) {
			if (check_erased_range(flash, info->erase_start, info->erase_len)) {
				msg_cerr(" ERASE_FAILED\n");
				return -1;
			}
		}

		/* Erase was successful. Adjust curcontents. */
		memset(info->curcontents, ERASED_VALUE(flash), info->erase_len);
		skip = 0;
		block_was_erased = 1;
	}
	/* get_next_write() sets starthere to a new value after the call. */
	while ((lenhere = get_next_write(info->curcontents + starthere,
					 info->newcontents + starthere,
					 info->erase_len - starthere, &starthere, gran))) {
		content_has_changed |= 1;
		if (!writecount++)
			msg_cdbg(" W");
		/* Needs the partial write function signature. */
		ret = write_flash(flash, (uint8_t *)info->newcontents + starthere,
				   info->erase_start + starthere, lenhere);
		if (ret) {
			if (ret == SPI_ACCESS_DENIED)
				msg_cdbg(" DENIED");
			return ret;
		}

		/*
		 * If the block needed to be erased and was erased successfully
		 * then we can assume that we didn't run into any write-
		 * protected areas. Otherwise, we need to verify each page to
		 * ensure it was successfully written and abort if we encounter
		 * any errors.
		 */
		if (programmer_table[programmer].paranoid && !block_was_erased) {
			if (verify_range(flash, info->newcontents + starthere,
					info->erase_start + starthere, lenhere))
				return -1;
		}

		starthere += lenhere;
		skip = 0;
	}
	if (skip)
		msg_cdbg(" SKIP");
	return ret;
}

int erase_and_write_flash(struct flashctx *flash,
			  struct action_descriptor *descriptor)
{
	int ret = 1;

	msg_cinfo("Erasing and writing flash chip... ");

	ret = walk_eraseregions(flash, &erase_and_write_block_helper, descriptor);

	if (ret) {
		msg_cerr("FAILED!\n");
	} else {
		msg_cdbg("SUCCESS.\n");
	}
	return ret;
}

static int verify_flash(struct flashctx *flash,
			struct action_descriptor *descriptor,
			int verify_it)
{
	int ret;
	unsigned int total_size = flash->chip->total_size * 1024;
	uint8_t *buf = descriptor->newcontents;

	msg_cinfo("Verifying flash... ");

	if (verify_it == VERIFY_PARTIAL) {
		struct processing_unit *pu = descriptor->processing_units;

		/* Verify only areas which were written. */
		while (pu->num_blocks) {
			ret = verify_range(flash, buf + pu->offset, pu->offset,
					   pu->block_size * pu->num_blocks);
			if (ret)
				break;
			pu++;
		}
	} else {
		ret = verify_range(flash, buf, 0, total_size);
	}

	if (ret == SPI_ACCESS_DENIED) {
		msg_gdbg("Could not fully verify due to access error, ");
		if (access_denied_action == error_ignore) {
			msg_gdbg("ignoring\n");
			ret = 0;
		} else {
			msg_gdbg("aborting\n");
		}
	}

	if (!ret)
		msg_cinfo("VERIFIED.          \n");

	return ret;
}

static void nonfatal_help_message(void)
{
	msg_gerr("Good, writing to the flash chip apparently didn't do anything.\n");
#if CONFIG_INTERNAL == 1
	if (programmer == PROGRAMMER_INTERNAL)
		msg_gerr("This means we have to add special support for your board, programmer or flash\n"
			 "chip. Please report this on IRC at chat.freenode.net (channel #flashrom) or\n"
			 "mail flashrom@flashrom.org, thanks!\n"
			 "-------------------------------------------------------------------------------\n"
			 "You may now reboot or simply leave the machine running.\n");
	else
#endif
		msg_gerr("Please check the connections (especially those to write protection pins) between\n"
			 "the programmer and the flash chip. If you think the error is caused by flashrom\n"
			 "please report this on IRC at chat.freenode.net (channel #flashrom) or\n"
			 "mail flashrom@flashrom.org, thanks!\n");
}

static void emergency_help_message(void)
{
	msg_gerr("Your flash chip is in an unknown state.\n");
#if CONFIG_INTERNAL == 1
	if (programmer == PROGRAMMER_INTERNAL)
		msg_gerr("Get help on IRC at chat.freenode.net (channel #flashrom) or\n"
			"mail flashrom@flashrom.org with the subject \"FAILED: <your board name>\"!\n"
			"-------------------------------------------------------------------------------\n"
			"DO NOT REBOOT OR POWEROFF!\n");
	else
#endif
		msg_gerr("Please report this on IRC at chat.freenode.net (channel #flashrom) or\n"
			 "mail flashrom@flashrom.org, thanks!\n");
}

void list_programmers_linebreak(int startcol, int cols, int paren)
{
	const char *pname;
	int pnamelen;
	int remaining = 0, firstline = 1;
	enum programmer p;
	int i;

	for (p = 0; p < PROGRAMMER_INVALID; p++) {
		pname = programmer_table[p].name;
		pnamelen = strlen(pname);
		if (remaining - pnamelen - 2 < 0) {
			if (firstline)
				firstline = 0;
			else
				msg_ginfo("\n");
			for (i = 0; i < startcol; i++)
				msg_ginfo(" ");
			remaining = cols - startcol;
		} else {
			msg_ginfo(" ");
			remaining--;
		}
		if (paren && (p == 0)) {
			msg_ginfo("(");
			remaining--;
		}
		msg_ginfo("%s", pname);
		remaining -= pnamelen;
		if (p < PROGRAMMER_INVALID - 1) {
			msg_ginfo(",");
			remaining--;
		} else {
			if (paren)
				msg_ginfo(")");
		}
	}
}

static void print_sysinfo(void)
{
#if IS_WINDOWS
	SYSTEM_INFO si;
	OSVERSIONINFOEX osvi;

	memset(&si, 0, sizeof(SYSTEM_INFO));
	memset(&osvi, 0, sizeof(OSVERSIONINFOEX));
	msg_ginfo(" on Windows");
	/* Tell Windows which version of the structure we want. */
	osvi.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX);
	if (GetVersionEx((OSVERSIONINFO*) &osvi))
		msg_ginfo(" %lu.%lu", osvi.dwMajorVersion, osvi.dwMinorVersion);
	else
		msg_ginfo(" unknown version");
	GetSystemInfo(&si);
	switch (si.wProcessorArchitecture) {
	case PROCESSOR_ARCHITECTURE_AMD64:
		msg_ginfo(" (x86_64)");
		break;
	case PROCESSOR_ARCHITECTURE_INTEL:
		msg_ginfo(" (x86)");
		break;
	default:
		msg_ginfo(" (unknown arch)");
		break;
	}
#elif HAVE_UTSNAME == 1
	struct utsname osinfo;

	uname(&osinfo);
	msg_ginfo(" on %s %s (%s)", osinfo.sysname, osinfo.release,
		  osinfo.machine);
#else
	msg_ginfo(" on unknown machine");
#endif
}

void print_buildinfo(void)
{
	msg_gdbg("flashrom was built with");
#if NEED_PCI == 1
#ifdef PCILIB_VERSION
	msg_gdbg(" libpci %s,", PCILIB_VERSION);
#else
	msg_gdbg(" unknown PCI library,");
#endif
#endif
#ifdef __clang__
	msg_gdbg(" LLVM Clang");
#ifdef __clang_version__
	msg_gdbg(" %s,", __clang_version__);
#else
	msg_gdbg(" unknown version (before r102686),");
#endif
#elif defined(__GNUC__)
	msg_gdbg(" GCC");
#ifdef __VERSION__
	msg_gdbg(" %s,", __VERSION__);
#else
	msg_gdbg(" unknown version,");
#endif
#else
	msg_gdbg(" unknown compiler,");
#endif
#if defined (__FLASHROM_LITTLE_ENDIAN__)
	msg_gdbg(" little endian");
#elif defined (__FLASHROM_BIG_ENDIAN__)
	msg_gdbg(" big endian");
#else
#error Endianness could not be determined
#endif
	msg_gdbg("\n");
}

void print_version(void)
{
	msg_ginfo("flashrom %s", flashrom_version);
	print_sysinfo();
	msg_ginfo("\n");
}

void print_banner(void)
{
	msg_ginfo("flashrom is free software, get the source code at "
		  "https://flashrom.org\n");
	msg_ginfo("\n");
}

int selfcheck(void)
{
	unsigned int i;
	int ret = 0;

	/* Safety check. Instead of aborting after the first error, check
	 * if more errors exist.
	 */
	if (ARRAY_SIZE(programmer_table) - 1 != PROGRAMMER_INVALID) {
		msg_gerr("Programmer table miscompilation!\n");
		ret = 1;
	}
	for (i = 0; i < PROGRAMMER_INVALID; i++) {
		const struct programmer_entry p = programmer_table[i];
		if (p.name == NULL) {
			msg_gerr("All programmers need a valid name, but the one with index %d does not!\n", i);
			ret = 1;
			/* This might hide other problems with this programmer, but allows for better error
			 * messages below without jumping through hoops. */
			continue;
		}
		switch (p.type) {
		case USB:
		case PCI:
		case OTHER:
			if (p.devs.note == NULL) {
				if (strcmp("internal", p.name) == 0)
					break; /* This one has its device list stored separately. */
				msg_gerr("Programmer %s has neither a device list nor a textual description!\n",
					 p.name);
				ret = 1;
			}
			break;
		default:
			msg_gerr("Programmer %s does not have a valid type set!\n", p.name);
			ret = 1;
			break;
		}
		if (p.init == NULL) {
			msg_gerr("Programmer %s does not have a valid init function!\n", p.name);
			ret = 1;
		}
		if (p.delay == NULL) {
			msg_gerr("Programmer %s does not have a valid delay function!\n", p.name);
			ret = 1;
		}
		if (p.map_flash_region == NULL) {
			msg_gerr("Programmer %s does not have a valid map_flash_region function!\n", p.name);
			ret = 1;
		}
		if (p.unmap_flash_region == NULL) {
			msg_gerr("Programmer %s does not have a valid unmap_flash_region function!\n", p.name);
			ret = 1;
		}
	}

	/* It would be favorable if we could check for the correct layout (especially termination) of various
	 * constant arrays: flashchips, chipset_enables, board_matches, boards_known, laptops_known.
	 * They are all defined as externs in this compilation unit so we don't know their sizes which vary
	 * depending on compiler flags, e.g. the target architecture, and can sometimes be 0.
	 * For 'flashchips' we export the size explicitly to work around this and to be able to implement the
	 * checks below. */
	if (flashchips_size <= 1 || flashchips[flashchips_size - 1].name != NULL) {
		msg_gerr("Flashchips table miscompilation!\n");
		ret = 1;
	} else {
		for (i = 0; i < flashchips_size - 1; i++) {
			const struct flashchip *chip = &flashchips[i];
			if (chip->vendor == NULL || chip->name == NULL || chip->bustype == BUS_NONE) {
				ret = 1;
				msg_gerr("ERROR: Some field of flash chip #%d (%s) is misconfigured.\n"
					 "Please report a bug at flashrom@flashrom.org\n", i,
					 chip->name == NULL ? "unnamed" : chip->name);
			}
			if (selfcheck_eraseblocks(chip)) {
				ret = 1;
			}
		}
	}

	/* TODO: implement similar sanity checks for other arrays where deemed necessary. */
	return ret;
}

/* FIXME: This function signature needs to be improved once doit() has a better
 * function signature.
 */
static int chip_safety_check(const struct flashctx *flash, int force,
			     int read_it, int write_it, int erase_it, int verify_it)
{
	const struct flashchip *chip = flash->chip;

	if (!programmer_may_write && (write_it || erase_it)) {
		msg_perr("Write/erase is not working yet on your programmer in "
			 "its current configuration.\n");
		/* --force is the wrong approach, but it's the best we can do
		 * until the generic programmer parameter parser is merged.
		 */
		if (!force)
			return 1;
		msg_cerr("Continuing anyway.\n");
	}

	if (read_it || erase_it || write_it || verify_it) {
		/* Everything needs read. */
		if (chip->tested.read == BAD) {
			msg_cerr("Read is not working on this chip. ");
			if (!force)
				return 1;
			msg_cerr("Continuing anyway.\n");
		}
		if (!chip->read) {
			msg_cerr("flashrom has no read function for this "
				 "flash chip.\n");
			return 1;
		}
	}
	if (erase_it || write_it) {
		/* Write needs erase. */
		if (chip->tested.erase == NA) {
			msg_cerr("Erase is not possible on this chip.\n");
			return 1;
		}
		if (chip->tested.erase == BAD) {
			msg_cerr("Erase is not working on this chip. ");
			if (!force)
				return 1;
			msg_cerr("Continuing anyway.\n");
		}
		if(count_usable_erasers(flash) == 0) {
			msg_cerr("flashrom has no erase function for this "
				 "flash chip.\n");
			return 1;
		}
	}
	if (write_it) {
		if (chip->tested.write == NA) {
			msg_cerr("Write is not possible on this chip.\n");
			return 1;
		}
		if (chip->tested.write == BAD) {
			msg_cerr("Write is not working on this chip. ");
			if (!force)
				return 1;
			msg_cerr("Continuing anyway.\n");
		}
		if (!chip->write) {
			msg_cerr("flashrom has no write function for this "
				 "flash chip.\n");
			return 1;
		}
	}
	return 0;
}

int prepare_flash_access(struct flashctx *const flash,
			 const bool read_it, const bool write_it,
			 const bool erase_it, const bool verify_it)
{
	if (chip_safety_check(flash, flash->flags.force, read_it, write_it, erase_it, verify_it)) {
		msg_cerr("Aborting.\n");
		return 1;
	}

	if (normalize_romentries(flash)) {
		msg_cerr("Requested regions can not be handled. Aborting.\n");
		return 1;
	}

	/*
	 * FIXME(b/171093672): Failures to map_flash() on some DUT's due to unknown cause,
	 * can be repro'ed with upstream on Volteer.
	 *
	 * map_flash() can fail on opaque spi drv such as linux_mtd and even ichspi.
         * The issue is that 'internal' [alias 'host'] has the cb 'map_flash_region = physmap'
         * hooked and this can fail on some board topologies. Checking the return value can
         * cause board rw failures by bailing early. Avoid the early bail for now until a
	 * full investigation can reveal the proper fix. This restores previous behaviour of
	 * assuming a map went fine.
	 */
#if 0
	if (map_flash(flash) != 0)
		return 1;
#endif
	map_flash(flash);

	/* Given the existence of read locks, we want to unlock for read,
	   erase and write. */
	if (flash->chip->unlock)
		flash->chip->unlock(flash);

	flash->address_high_byte = -1;
	flash->in_4ba_mode = false;
	flash->chip_restore_fn_count = 0;

	/* Be careful about 4BA chips and broken masters */
	if (flash->chip->total_size > 16 * 1024 && spi_master_no_4ba_modes(flash)) {
		/* If we can't use native instructions, bail out */
		if ((flash->chip->feature_bits & FEATURE_4BA_NATIVE) != FEATURE_4BA_NATIVE
		    || !spi_master_4ba(flash)) {
			msg_cerr("Programmer doesn't support this chip. Aborting.\n");
			return 1;
		}
	}

	return 0;
}

void finalize_flash_access(struct flashctx *const flash)
{
	deregister_chip_restore(flash);
	unmap_flash(flash);
}

/**
 * @addtogroup flashrom-flash
 * @{
 */

/**
 * @brief Erase the specified ROM chip.
 *
 * If a layout is set in the given flash context, only included regions
 * will be erased.
 *
 * @param flashctx The context of the flash chip to erase.
 * @return 0 on success.
 */
static int flashrom_flash_erase(struct flashctx *const flashctx,
				void *oldcontents, void *newcontents, size_t size)
{
	/*
	 * To make sure that the chip is fully erased, let's cheat and create
	 * a descriptor where the new contents are all erased.
	 */
	struct action_descriptor *fake_descriptor;
	int ret = 0;

	fake_descriptor = prepare_action_descriptor(flashctx, oldcontents,
						    newcontents, 1);
	/* FIXME: Do we really want the scary warning if erase failed? After
	 * all, after erase the chip is either blank or partially blank or it
	 * has the old contents. A blank chip won't boot, so if the user
	 * wanted erase and reboots afterwards, the user knows very well that
	 * booting won't work.
	 */
	if (erase_and_write_flash(flashctx, fake_descriptor)) {
		emergency_help_message();
		ret = 1;
	}

	free(fake_descriptor);

	return ret;
}

/** @} */ /* end flashrom-flash */

/**
 * @defgroup flashrom-ops Operations
 * @{
 */


/**
 * @brief Read the current image from the specified ROM chip.
 *
 * If a layout is set in the specified flash context, only included regions
 * will be read.
 *
 * @param flashctx The context of the flash chip.
 * @param buffer Target buffer to write image to.
 * @param buffer_len Size of target buffer in bytes.
 * @return 0 on success,
 *         2 if buffer_len is too short for the flash chip's contents,
 *         or 1 on any other failure.
 */
int flashrom_image_read(struct flashctx *const flashctx, int verify_it,
                        void *const buffer, const size_t buffer_len)
{
	if (((verify_it == VERIFY_OFF) || (verify_it == VERIFY_PARTIAL))
			&& get_num_include_args()) {
		/*
		 * If no full verification is required and not
		 * the entire chip is about to be programmed,
		 * read only the areas which might change.
		 */
		if (handle_partial_read(flashctx, buffer, read_flash, 0) < 0)
			return 1;
	} else {
		if (read_flash(flashctx, buffer, 0, buffer_len))
			return 1;
	}
	return 0;
}

/* This function signature is horrible. We need to design a better interface,
 * but right now it allows us to split off the CLI code.
 * Besides that, the function itself is a textbook example of abysmal code flow.
 *
 *
 * The main processing function of flashrom utility; it is invoked once
 * command line parameters are processed and verified, and the type of the
 * flash chip the programmer operates on has been determined.
 *
 * @flash	  pointer to the flash context matching the chip detected
 *		  during initialization.
 * @force         when set proceed even if the chip is not known to work
 * @filename      pointer to the name of the file to read from or write to
 * @read_it       when true, flash contents are read into 'filename'
 * @write_it      when true, flash is programmed with 'filename' contents
 * @erase_it      when true, flash chip is erased
 * @verify_it	  depending on the value verify the full chip, only changed
 *		  areas, or none
 * @extract_it    extract all known flash chip regions into separate files
 * @diff_file	  when deciding what areas to program, use this file's
 *                contents instead of reading the current chip contents
 * @do_diff	  when true - compare result of the operation with either the
 *		  original chip contents for 'diff_file' contents, is present.
 *		  When false - do not diff, consider the chip erased before
 *		  operation starts.
 *
 * Only one of 'read_it', 'write_it', and 'erase_it' is expected to be set,
 * but this is not enforced.
 *
 * 'do_diff' must be set if 'diff_file' is set. If 'do_diff' is set, but
 * 'diff_file' is not - comparison is done against the pre-operation chip
 * contents.
 */
int doit(struct flashctx *flash, const char *filename, int read_it,
	 int write_it, int erase_it, int verify_it,
	 const char *diff_file)
{
	uint8_t *oldcontents;
	uint8_t *newcontents;
	int ret = 0;
	unsigned long size = flash->chip->total_size * 1024;
	struct action_descriptor *descriptor = NULL;

	oldcontents = malloc(size);
	if (!oldcontents) {
		msg_gerr("Out of memory!\n");
		exit(1);
	}
	/* Assume worst case: All blocks are not erased. */
	memset(oldcontents, UNERASED_VALUE(flash), size);
	newcontents = malloc(size);
	if (!newcontents) {
		msg_gerr("Out of memory!\n");
		exit(1);
	}
	/* Assume best case: All blocks are erased. */
	memset(newcontents, ERASED_VALUE(flash), size);
	/* Side effect of the assumptions above: Default write action is erase
	 * because newcontents looks like a completely erased chip, and
	 * oldcontents being completely unerased means we have to erase
	 * everything before we can write.
	 */

	if (write_it || verify_it) {
		/*
		 * Note: This must be done before any files specified by -i
		 * arguments are processed merged into the newcontents since
		 * -i files take priority. See http://crbug.com/263495.
		 */
		if (filename) {
			if (read_buf_from_file(newcontents, size, filename)) {
				ret = 1;
				goto out;
			}
		} else {
			/* Content will be read from -i args, so they must
			 * not overlap. */
			if (included_regions_overlap()) {
				msg_gerr("Error: Included regions must "
						"not overlap.\n");
				ret = 1;
				goto out;
			}
		}
	}

	if (flash->flags.do_diff) {
		/*
		 * Obtain a reference image so that we can check whether
		 * regions need to be erased and to give better diagnostics in
		 * case write fails. If --fast-verify is used then only the
		 * regions which are included using -i will be read.
		 */
		if (diff_file) {
			msg_cdbg("Reading old contents from file... ");
			if (read_buf_from_file(oldcontents, size, diff_file)) {
				ret = 1;
				msg_cdbg("FAILED.\n");
				goto out;
			}
		} else {
			msg_cdbg("Reading old contents from flash chip... ");
			ret = flashrom_image_read(flash, verify_it, oldcontents, size);
			if (ret) {
				msg_cdbg("FAILED.\n");
				goto out;
			}
		}
		msg_cdbg("done.\n");
	} else if (!erase_it) {
		msg_pinfo("No diff performed, considering the chip erased.\n");
		memset(oldcontents, ERASED_VALUE(flash), size);
	}

	/*
	 * Note: This must be done after reading the file specified for the
	 * -w/-v argument, if any, so that files specified using -i end up
	 * in the "newcontents" buffer before being written.
	 * See http://crbug.com/263495.
	 */
	if (build_new_image(flash, oldcontents, newcontents, erase_it)) {
		ret = 1;
		msg_cerr("Error handling ROM entries.\n");
		goto out;
	}

	if (erase_it) {
		flashrom_flash_erase(flash, oldcontents, newcontents, size);
		goto verify;
	}

	descriptor = prepare_action_descriptor(flash, oldcontents,
					       newcontents, flash->flags.do_diff);
	if (write_it) {
		// parse the new fmap and disable soft WP if necessary
		if ((ret = cros_ec_prepare(newcontents, size))) {
			msg_cerr("CROS_EC prepare failed, ret=%d.\n", ret);
			goto out;
		}

		if (erase_and_write_flash(flash, descriptor)) {
			msg_cerr("Uh oh. Erase/write failed. Checking if anything changed.\n");
			msg_cinfo("Reading current flash chip contents... ");
			if (!read_flash(flash, newcontents, 0, size)) {
				msg_cinfo("done.\n");
				if (!memcmp(oldcontents, newcontents, size)) {
					nonfatal_help_message();
					ret = 1;
					goto out;
				}
				msg_cerr("Apparently at least some data has changed.\n");
			} else
				msg_cerr("Can't even read anymore!\n");
			emergency_help_message();
			ret = 1;
			goto out;
		}

		ret = cros_ec_need_2nd_pass();
		if (ret < 0) {
			// Jump failed
			msg_cerr("cros_ec_need_2nd_pass() failed. Stop.\n");
			emergency_help_message();
			ret = 1;
			goto out;
		} else if (ret > 0) {
			// Need 2nd pass. Get the just written content.
			msg_pdbg("CROS_EC needs 2nd pass.\n");
			ret = flashrom_image_read(flash, verify_it, oldcontents, size);
			if (ret) {
				emergency_help_message();
				goto out;
			}

			/* Get a new descriptor. */
			free(descriptor);
			descriptor = prepare_action_descriptor(flash,
							       oldcontents,
							       newcontents,
							       flash->flags.do_diff);
			// write 2nd pass
			if (erase_and_write_flash(flash, descriptor)) {
				msg_cerr("Uh oh. CROS_EC 2nd pass failed.\n");
				emergency_help_message();
				ret = 1;
				goto out;
			}
			ret = 0;
		}

		if (cros_ec_finish() < 0) {
			msg_cerr("cros_ec_finish() failed. Stop.\n");
			emergency_help_message();
			ret = 1;
			goto out;
		}
	}

 verify:
	if (verify_it) {
		if ((write_it || erase_it) && !content_has_changed) {
			msg_gdbg("Nothing was erased or written, skipping "
				"verification\n");
		} else {
			/* Work around chips which need some time to calm down. */
			if (write_it && verify_it != VERIFY_PARTIAL)
				programmer_delay(1000*1000);

			ret = verify_flash(flash, descriptor, verify_it);

			/* If we tried to write, and verification now fails, we
			 * might have an emergency situation.
			 */
			if (ret && write_it)
				emergency_help_message();
		}
	}

out:
	if (descriptor)
		free(descriptor);

	free(oldcontents);
	free(newcontents);
	/*
	 * programmer_shutdown() call is moved to cli_classic() in chromium os
	 * tree. This is because some operations, such as write protection,
	 * requires programmer_shutdown() but does not call doit().
	 */
//	programmer_shutdown();
	return ret;
}

/** @} */ /* end flashrom-ops */

int do_read(struct flashctx *const flash, const char *const filename)
{
	if (prepare_flash_access(flash, true, false, false, false))
		return 1;

	const int ret = read_flash_to_file(flash, filename);

	finalize_flash_access(flash);

	return ret;
}

int do_erase(struct flashctx *const flash, const char *diff_file)
{
	if (prepare_flash_access(flash, false, false, true, false))
		return 1;

	int ret = doit(flash, NULL, false, false, true, false, diff_file);

	/*
	 * FIXME: Do we really want the scary warning if erase failed?
	 * After all, after erase the chip is either blank or partially
	 * blank or it has the old contents. A blank chip won't boot,
	 * so if the user wanted erase and reboots afterwards, the user
	 * knows very well that booting won't work.
	 */
	if (ret)
		emergency_help_message();
	finalize_flash_access(flash);

	return ret;
}

int do_write(struct flashctx *const flash, const char *const filename, const char *const referencefile, const char *diff_file)
{
	if (prepare_flash_access(flash, false, true, false, flash->flags.verify_after_write))
		return 1;

	int ret = doit(flash, filename, false, true, false,
		       flash->flags.verify_after_write
			       ? flash->flags.verify_whole_chip ? VERIFY_FULL : VERIFY_PARTIAL
			       : 0,
		       diff_file);
	finalize_flash_access(flash);

	return ret;
}

int do_verify(struct flashctx *const flash, const char *const filename, const char *diff_file)
{
	if (prepare_flash_access(flash, false, false, false, true))
		return 1;

	int ret = doit(flash, filename, false, false, false, flash->flags.verify_whole_chip ? VERIFY_FULL : VERIFY_PARTIAL, diff_file);
	finalize_flash_access(flash);

	return ret;
}

int do_extract_it(struct flashctx *const flash)
{
	if (prepare_flash_access(flash, false, false, false, false))
		return 1;
	int ret = extract_regions(flash);
	finalize_flash_access(flash);

	return ret;
}