linux_spi.c - chromiumos/third_party/flashrom - Git at Google

 /*
  * This file is part of the flashrom project.
  *
  * Copyright (C) 2011 Sven Schnelle <svens@stackframe.org>
  *
  * 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; version 2 of the License.
  *
  * 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 <string.h>
 #include <stdlib.h>
 #include <sys/fcntl.h>
 #include <errno.h>
 #include <ctype.h>
 #include <unistd.h>
 #include <linux/spi/spidev.h>
 #include <sys/ioctl.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include "file.h"
 #include "flash.h"
 #include "chipdrivers.h"
 #include "programmer.h"
 #include "spi.h"


 /* TODO: this information should come from the SPI master driver. */
 #define SPI_DMA_SIZE 64

 #ifndef SPIDEV_MAJOR
 #define SPIDEV_MAJOR 153  /* refer to kernel/files/drivers/spi/spidev.c */
 #endif

 #define MODALIAS_FILE		"modalias"
 #define LINUX_SPI_SYSFS_ROOT	"/sys/bus/spi/devices"

 static int fd = -1;

 static int linux_spi_shutdown(void *data);
 static int linux_spi_send_command(const struct flashctx *flash, unsigned int writecnt, unsigned int readcnt,
 			const unsigned char *txbuf, unsigned char *rxbuf);
 static int linux_spi_read(struct flashctx *flash, uint8_t *buf,
 			  unsigned int start, unsigned int len);
 static int linux_spi_write_256(struct flashctx *flash, const uint8_t *buf,
 			       unsigned int start, unsigned int len);

 static const struct spi_master spi_master_linux = {
 	.type		= SPI_CONTROLLER_LINUX,
 	.max_data_read	= MAX_DATA_UNSPECIFIED, /* TODO? */
 	.max_data_write	= MAX_DATA_UNSPECIFIED, /* TODO? */
 	.command	= linux_spi_send_command,
 	.multicommand	= default_spi_send_multicommand,
 	.read		= linux_spi_read,
 	.write_256	= linux_spi_write_256,
 };

 static char devfs_path[32]; 	/* at least big enough to fit /dev/spidevX.Y */
 static char *check_sysfs(void)
 {
 	int i;
 	const char *sysfs_path = NULL;
 	char *p;
 	char *modalias[] = {
 		"spi:spidev",	/* raw access over SPI bus (newer kernels) */
 		"spidev",	/* raw access over SPI bus (older kernels) */
 		"m25p80",	/* generic MTD device */
 	};

 	for (i = 0; i < ARRAY_SIZE(modalias); i++) {
 		int major, minor;

 		/* Path should look like: /sys/blah/spiX.Y/modalias */
 		sysfs_path = scanft(LINUX_SPI_SYSFS_ROOT,
 				MODALIAS_FILE, modalias[i], 1);
 		if (!sysfs_path)
 			continue;

 		p = (char *)sysfs_path + strlen(LINUX_SPI_SYSFS_ROOT);
 		if (p[0] == '/')
 			p++;

 		if (sscanf(p, "spi%u.%u", &major, &minor) == 2) {
 			msg_pdbg("Found SPI device %s on spi%u.%u\n",
 				modalias[i], major, minor);
 			sprintf(devfs_path, "/dev/spidev%u.%u", major, minor);
 			free((void *)sysfs_path);
 			break;
 		}
 		free((void *)sysfs_path);
 	}

 	if (i == ARRAY_SIZE(modalias))
 		return NULL;
 	return devfs_path;
 }

 static char *check_fdt(void)
 {
 	unsigned int bus, cs;

 	if (fdt_find_spi_nor_flash(&bus, &cs) < 0)
 		return NULL;

 	sprintf(devfs_path, "/dev/spidev%u.%u", bus, cs);
 	return devfs_path;
 }

 static char *linux_spi_probe(void)
 {
 	char *ret;

 	ret = check_fdt();
 	if (ret)
 		return ret;

 	ret = check_sysfs();
 	if (ret)
 		return ret;

 	return NULL;
 }

 /*
  * This is used when /dev/spidevX.Y is not created yet, for example, when
  * udev is not started.
  */
 static int manual_mknod(const char *dev)
 {
 	char cmd[256];

 	msg_pdbg("Creating SPI device node %s...\n", dev);
 	strcpy(cmd, "modprobe spidev");
 	msg_pdbg("CMD: [%s]\n", cmd);
 	if (system(cmd)) {
 		msg_perr("%s: failed to run '%s': %s\n", __func__,
 			 cmd, strerror(errno));
 		return -1;
 	}
 	snprintf(cmd, sizeof(cmd), "mknod %s c %d 0", dev, SPIDEV_MAJOR);
 	msg_pdbg("CMD: [%s]\n", cmd);
 	if (system(cmd)) {
 		msg_perr("%s: failed to run '%s': %s\n", __func__,
 			 cmd, strerror(errno));
 		return -1;
 	}

 	if ((fd = open(dev, O_RDWR)) == -1) {
 		msg_perr("%s: failed to open %s: %s\n", __func__,
 			 dev, strerror(errno));
 	}

 	return fd;
 }


 int linux_spi_init(void)
 {
 	char *p, *endp, *dev;
 	uint32_t speed = 0;

 	/*
 	 * FIXME: There might be other programmers with flash memory (such as
 	 * an EC) connected via SPI. For now we rely on the device's driver to
 	 * distinguish it and assume generic SPI implies host.
 	 */
 	if (alias && alias->type != ALIAS_HOST)
 		return 1;

 	dev = extract_programmer_param("dev");
 	if (!dev)
 		dev = linux_spi_probe();
 	if (!dev || !strlen(dev)) {
 		msg_perr("No SPI device found. Use flashrom -p "
 			 "linux_spi:dev=/dev/spidevX.Y\n");
 		return 1;
 	}

 	p = extract_programmer_param("speed");
 	if (p && strlen(p)) {
 		speed = (uint32_t)strtoul(p, &endp, 10) * 1024;
 		if (p == endp) {
 			msg_perr("%s: invalid clock: %s kHz\n", __func__, p);
 			return 1;
 		}
 	}

 	msg_pdbg("Using device %s\n", dev);
 	if ((fd = open(dev, O_RDWR)) == -1) {
 		msg_pdbg("%s: failed to open %s: %s\n", __func__,
 			 dev, strerror(errno));

 		if (manual_mknod(dev) == -1) {  // global fd is effected.
 			return 1;
 		}
 	}

 	if (speed > 0) {
 		if (ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed) == -1) {
 			msg_perr("%s: failed to set speed %dHz: %s\n",
 				 __func__, speed, strerror(errno));
 			close(fd);
 			return 1;
 		}

 		msg_pdbg("Using %d kHz clock\n", speed);
 	}

 	if (register_shutdown(linux_spi_shutdown, NULL))
 		return 1;

 	register_spi_master(&spi_master_linux);

 	return 0;
 }

 static int linux_spi_shutdown(void *data)
 {
 	if (fd != -1) {
 		close(fd);
 		fd = -1;
 	}
 	return 0;
 }

 static int linux_spi_send_command(const struct flashctx *flash, unsigned int writecnt, unsigned int readcnt,
 			const unsigned char *txbuf, unsigned char *rxbuf)
 {
 	int msg_start = 0, msg_count = 0;
 	struct spi_ioc_transfer msg[2] = {
 		{
 			.tx_buf = (uint64_t)(uintptr_t)txbuf,
 			.len = writecnt,
 		},
 		{
 			.rx_buf = (uint64_t)(uintptr_t)rxbuf,
 			.len = readcnt,
 		},
 	};

 	if (fd == -1)
 		return -1;

 	/* Only pass necessary msg[] to ioctl() to avoid the empty message
 	 * which drives an un-expected CS line and clocks. */
 	if (writecnt) {
 		msg_start = 0;  /* tx: msg[0] */
 		msg_count++;
 		if (readcnt) {
 			msg_count++;
 		}
 	} else if (readcnt) {
 		msg_start = 1;  /* rx: msg[1] */
 		msg_count++;
 	} else {
 		msg_cerr("%s: both writecnt and readcnt are 0.\n",
 			 __func__);
 		return -1;
 	}

 	if (ioctl(fd, SPI_IOC_MESSAGE(msg_count), &msg[msg_start]) == -1) {
 		msg_cerr("%s: ioctl: %s\n", __func__, strerror(errno));
 		return -1;
 	}
 	return 0;
 }

 static int linux_spi_read(struct flashctx *flash, uint8_t *buf,
 			  unsigned int start, unsigned int len)
 {
 	return spi_read_chunked(flash, buf, start, len, SPI_DMA_SIZE);
 }

 static int linux_spi_write_256(struct flashctx *flash, const uint8_t *buf,
 			       unsigned int start, unsigned int len)
 {
 	return spi_write_chunked(flash, buf, start, len,
 				 SPI_DMA_SIZE - 5 /* WREN, Page Program */);
 }
	/*
	* This file is part of the flashrom project.
	*
	* Copyright (C) 2011 Sven Schnelle <svens@stackframe.org>
	*
	* 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; version 2 of the License.
	*
	* 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 <string.h>
	#include <stdlib.h>
	#include <sys/fcntl.h>
	#include <errno.h>
	#include <ctype.h>
	#include <unistd.h>
	#include <linux/spi/spidev.h>
	#include <sys/ioctl.h>
	#include <sys/stat.h>
	#include <sys/types.h>
	#include "file.h"
	#include "flash.h"
	#include "chipdrivers.h"
	#include "programmer.h"
	#include "spi.h"



	/* TODO: this information should come from the SPI master driver. */
	#define SPI_DMA_SIZE 64

	#ifndef SPIDEV_MAJOR
	#define SPIDEV_MAJOR 153 /* refer to kernel/files/drivers/spi/spidev.c */
	#endif

	#define MODALIAS_FILE "modalias"
	#define LINUX_SPI_SYSFS_ROOT "/sys/bus/spi/devices"

	static int fd = -1;

	static int linux_spi_shutdown(void *data);
	static int linux_spi_send_command(const struct flashctx *flash, unsigned int writecnt, unsigned int readcnt,
	const unsigned char txbuf, unsigned char rxbuf);
	static int linux_spi_read(struct flashctx flash, uint8_t buf,
	unsigned int start, unsigned int len);
	static int linux_spi_write_256(struct flashctx flash, const uint8_t buf,
	unsigned int start, unsigned int len);

	static const struct spi_master spi_master_linux = {
	.type = SPI_CONTROLLER_LINUX,
	.max_data_read = MAX_DATA_UNSPECIFIED, /* TODO? */
	.max_data_write = MAX_DATA_UNSPECIFIED, /* TODO? */
	.command = linux_spi_send_command,
	.multicommand = default_spi_send_multicommand,
	.read = linux_spi_read,
	.write_256 = linux_spi_write_256,
	};

	static char devfs_path[32]; /* at least big enough to fit /dev/spidevX.Y */
	static char *check_sysfs(void)
	{
	int i;
	const char *sysfs_path = NULL;
	char *p;
	char *modalias[] = {
	"spi:spidev", /* raw access over SPI bus (newer kernels) */
	"spidev", /* raw access over SPI bus (older kernels) */
	"m25p80", /* generic MTD device */
	};

	for (i = 0; i < ARRAY_SIZE(modalias); i++) {
	int major, minor;

	/* Path should look like: /sys/blah/spiX.Y/modalias */
	sysfs_path = scanft(LINUX_SPI_SYSFS_ROOT,
	MODALIAS_FILE, modalias[i], 1);
	if (!sysfs_path)
	continue;

	p = (char *)sysfs_path + strlen(LINUX_SPI_SYSFS_ROOT);
	if (p[0] == '/')
	p++;

	if (sscanf(p, "spi%u.%u", &major, &minor) == 2) {
	msg_pdbg("Found SPI device %s on spi%u.%u\n",
	modalias[i], major, minor);
	sprintf(devfs_path, "/dev/spidev%u.%u", major, minor);
	free((void *)sysfs_path);
	break;
	}
	free((void *)sysfs_path);
	}

	if (i == ARRAY_SIZE(modalias))
	return NULL;
	return devfs_path;
	}

	static char *check_fdt(void)
	{
	unsigned int bus, cs;

	if (fdt_find_spi_nor_flash(&bus, &cs) < 0)
	return NULL;

	sprintf(devfs_path, "/dev/spidev%u.%u", bus, cs);
	return devfs_path;
	}

	static char *linux_spi_probe(void)
	{
	char *ret;

	ret = check_fdt();
	if (ret)
	return ret;

	ret = check_sysfs();
	if (ret)
	return ret;

	return NULL;
	}

	/*
	* This is used when /dev/spidevX.Y is not created yet, for example, when
	* udev is not started.
	*/
	static int manual_mknod(const char *dev)
	{
	char cmd[256];

	msg_pdbg("Creating SPI device node %s...\n", dev);
	strcpy(cmd, "modprobe spidev");
	msg_pdbg("CMD: [%s]\n", cmd);
	if (system(cmd)) {
	msg_perr("%s: failed to run '%s': %s\n", __func__,
	cmd, strerror(errno));
	return -1;
	}
	snprintf(cmd, sizeof(cmd), "mknod %s c %d 0", dev, SPIDEV_MAJOR);
	msg_pdbg("CMD: [%s]\n", cmd);
	if (system(cmd)) {
	msg_perr("%s: failed to run '%s': %s\n", __func__,
	cmd, strerror(errno));
	return -1;
	}

	if ((fd = open(dev, O_RDWR)) == -1) {
	msg_perr("%s: failed to open %s: %s\n", __func__,
	dev, strerror(errno));
	}

	return fd;
	}


	int linux_spi_init(void)
	{
	char p, endp, *dev;
	uint32_t speed = 0;

	/*
	* FIXME: There might be other programmers with flash memory (such as
	* an EC) connected via SPI. For now we rely on the device's driver to
	* distinguish it and assume generic SPI implies host.
	*/
	if (alias && alias->type != ALIAS_HOST)
	return 1;

	dev = extract_programmer_param("dev");
	if (!dev)
	dev = linux_spi_probe();
	if (!dev \|\| !strlen(dev)) {
	msg_perr("No SPI device found. Use flashrom -p "
	"linux_spi:dev=/dev/spidevX.Y\n");
	return 1;
	}

	p = extract_programmer_param("speed");
	if (p && strlen(p)) {
	speed = (uint32_t)strtoul(p, &endp, 10) * 1024;
	if (p == endp) {
	msg_perr("%s: invalid clock: %s kHz\n", __func__, p);
	return 1;
	}
	}

	msg_pdbg("Using device %s\n", dev);
	if ((fd = open(dev, O_RDWR)) == -1) {
	msg_pdbg("%s: failed to open %s: %s\n", __func__,
	dev, strerror(errno));

	if (manual_mknod(dev) == -1) { // global fd is effected.
	return 1;
	}
	}

	if (speed > 0) {
	if (ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed) == -1) {
	msg_perr("%s: failed to set speed %dHz: %s\n",
	__func__, speed, strerror(errno));
	close(fd);
	return 1;
	}

	msg_pdbg("Using %d kHz clock\n", speed);
	}

	if (register_shutdown(linux_spi_shutdown, NULL))
	return 1;

	register_spi_master(&spi_master_linux);

	return 0;
	}

	static int linux_spi_shutdown(void *data)
	{
	if (fd != -1) {
	close(fd);
	fd = -1;
	}
	return 0;
	}

	static int linux_spi_send_command(const struct flashctx *flash, unsigned int writecnt, unsigned int readcnt,
	const unsigned char txbuf, unsigned char rxbuf)
	{
	int msg_start = 0, msg_count = 0;
	struct spi_ioc_transfer msg[2] = {
	{
	.tx_buf = (uint64_t)(uintptr_t)txbuf,
	.len = writecnt,
	},
	{
	.rx_buf = (uint64_t)(uintptr_t)rxbuf,
	.len = readcnt,
	},
	};

	if (fd == -1)
	return -1;

	/* Only pass necessary msg[] to ioctl() to avoid the empty message
	* which drives an un-expected CS line and clocks. */
	if (writecnt) {
	msg_start = 0; /* tx: msg[0] */
	msg_count++;
	if (readcnt) {
	msg_count++;
	}
	} else if (readcnt) {
	msg_start = 1; /* rx: msg[1] */
	msg_count++;
	} else {
	msg_cerr("%s: both writecnt and readcnt are 0.\n",
	__func__);
	return -1;
	}

	if (ioctl(fd, SPI_IOC_MESSAGE(msg_count), &msg[msg_start]) == -1) {
	msg_cerr("%s: ioctl: %s\n", __func__, strerror(errno));
	return -1;
	}
	return 0;
	}

	static int linux_spi_read(struct flashctx flash, uint8_t buf,
	unsigned int start, unsigned int len)
	{
	return spi_read_chunked(flash, buf, start, len, SPI_DMA_SIZE);
	}

	static int linux_spi_write_256(struct flashctx flash, const uint8_t buf,
	unsigned int start, unsigned int len)
	{
	return spi_write_chunked(flash, buf, start, len,
	SPI_DMA_SIZE - 5 /* WREN, Page Program */);
	}