1 files changed, 152 insertions, 0 deletions
diff --git a/i2c_helper_linux.c b/i2c_helper_linux.c
new file mode 100644
index 000000000..19b4404fb
--- /dev/null
+++ b/i2c_helper_linux.c
@@ -0,0 +1,152 @@
+/*
+ * This file is part of the flashrom project.
+ *
+ * Copyright (C) 2020 The Chromium OS Authors
+ *
+ * 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 <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+#include <stdlib.h>
+#include <linux/i2c.h>
+#include <linux/i2c-dev.h>
+
+#include "flash.h"
+#include "i2c_helper.h"
+#include "programmer.h"
+
+/* Null characters are placeholders for bus number digits */
+#define I2C_DEV_PREFIX	"/dev/i2c-\0\0\0"
+#define I2C_MAX_BUS	255
+
+int i2c_close(int fd)
+{
+	return fd == -1 ? 0 : close(fd);
+}
+
+int i2c_open_path(const char *path, uint16_t addr, int force)
+{
+	int fd = open(path, O_RDWR);
+	if (fd < 0) {
+		msg_perr("Unable to open I2C device %s: %s.\n", path, strerror(errno));
+		return fd;
+	}
+
+	int request = force ? I2C_SLAVE_FORCE : I2C_SLAVE;
+	int ret = ioctl(fd, request, addr);
+	if (ret < 0) {
+		msg_perr("Unable to set I2C slave address to 0x%02x: %s.\n", addr, strerror(errno));
+		i2c_close(fd);
+		return ret;
+	}
+
+	return fd;
+}
+
+int i2c_open(int bus, uint16_t addr, int force)
+{
+	char dev[sizeof(I2C_DEV_PREFIX)] = {0};
+
+	int ret = -1;
+
+	if (bus < 0 || bus > I2C_MAX_BUS) {
+		msg_perr("Invalid I2C bus %d.\n", bus);
+		return ret;
+	}
+
+	ret = snprintf(dev, sizeof(dev), "%s%d", I2C_DEV_PREFIX, bus);
+	if (ret < 0) {
+		msg_perr("Unable to join bus number to device name: %s.\n", strerror(errno));
+		return ret;
+	}
+
+	return i2c_open_path(dev, addr, force);
+}
+
+static int get_bus_number(char *bus_str)
+{
+	char *bus_suffix;
+	errno = 0;
+	int bus = (int)strtol(bus_str, &bus_suffix, 10);
+	if (errno != 0 || bus_str == bus_suffix) {
+		msg_perr("%s: Could not convert 'bus'.\n", __func__);
+		return -1;
+	}
+
+	if (strlen(bus_suffix) > 0) {
+		msg_perr("%s: Garbage following 'bus' value.\n", __func__);
+		return -1;
+	}
+
+	msg_pinfo("Using I2C bus %d.\n", bus);
+	return bus;
+}
+
+int i2c_open_from_programmer_params(const struct programmer_cfg *cfg, uint16_t addr, int force)
+{
+	int fd = -1;
+
+	char *bus_str = extract_programmer_param_str(cfg, "bus");
+	char *device_path = extract_programmer_param_str(cfg, "devpath");
+
+	if (device_path != NULL && bus_str != NULL) {
+		msg_perr("%s: only one of bus and devpath may be specified\n", __func__);
+		goto out;
+	}
+	if (device_path == NULL && bus_str == NULL) {
+		msg_perr("%s: one of bus and devpath must be specified\n", __func__);
+		goto out;
+	}
+
+	if (device_path != NULL)
+		fd = i2c_open_path(device_path, addr, force);
+	else
+		fd = i2c_open(get_bus_number(bus_str), addr, force);
+
+out:
+	free(bus_str);
+	free(device_path);
+	return fd;
+}
+
+int i2c_read(int fd, uint16_t addr, i2c_buffer_t *buf)
+{
+	if (buf->len == 0)
+		return 0;
+
+	int ret = ioctl(fd, I2C_SLAVE, addr);
+	if (ret < 0) {
+		msg_perr("Unable to set I2C slave address to 0x%02x: %s.\n", addr, strerror(errno));
+		return ret;
+	}
+
+	return read(fd, buf->buf, buf->len);
+}
+
+int i2c_write(int fd, uint16_t addr, const i2c_buffer_t *buf)
+{
+	if (buf->len == 0)
+		return 0;
+
+	int ret = ioctl(fd, I2C_SLAVE, addr);
+	if (ret < 0) {
+		msg_perr("Unable to set I2C slave address to 0x%02x: %s.\n", addr, strerror(errno));
+		return ret;
+	}
+
+	return write(fd, buf->buf, buf->len);
+}