Merge "Add I2C host communication"

util/build.mk

@@ -7,5 +7,9 @@
 #
 
 host-util-bin=ectool lbplay
+ifeq ($(CONFIG_LPC),y)
 host-util-common=comm-lpc
+else
+host-util-common=comm-i2c
+endif
 build-util-bin=ec_uartd stm32mon

util/comm-i2c.c

@@ -0,0 +1,210 @@
+/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#define _GNU_SOURCE /* for asprintf */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/i2c.h>
+#include <linux/i2c-dev.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include "comm-host.h"
+#include "ec_commands.h"
+
+#define EC_I2C_ADDR 0x1e
+
+#define I2C_ADAPTER_NODE "/sys/class/i2c-adapter/i2c-%d/name"
+#define I2C_ADAPTER_NAME "cros_ec_i2c"
+#define I2C_MAX_ADAPTER  32
+#define I2C_NODE "/dev/i2c-%d"
+
+#ifdef DEBUG
+#define debug(format, arg...) printf(format, ##arg)
+#else
+#define debug(...)
+#endif
+
+static int i2c_fd = -1;
+
+int comm_init(void)
+{
+	char *file_path;
+	char buffer[64];
+	FILE *f;
+	int i;
+
+	/* find the device number based on the adapter name */
+	for (i = 0; i < I2C_MAX_ADAPTER; i++) {
+		if (asprintf(&file_path, I2C_ADAPTER_NODE, i) < 0)
+			return -1;
+		f = fopen(file_path, "r");
+		if (f) {
+			if (fgets(buffer, sizeof(buffer), f) &&
+			    !strncmp(buffer, I2C_ADAPTER_NAME, 6)) {
+				free(file_path);
+				break;
+			}
+			fclose(f);
+		}
+		free(file_path);
+	}
+	if (i == I2C_MAX_ADAPTER) {
+		fprintf(stderr, "Cannot find I2C adapter\n");
+		return -1;
+	}
+
+	if (asprintf(&file_path, I2C_NODE, i) < 0)
+		return -1;
+	debug("using I2C adapter %s\n", file_path);
+	i2c_fd = open(file_path, O_RDWR);
+	if (i2c_fd < 0)
+		fprintf(stderr, "Cannot open %s : %d\n", file_path, errno);
+
+	free(file_path);
+	return 0;
+}
+
+
+/* Sends a command to the EC.  Returns the command status code, or
+ * -1 if other error. */
+int ec_command(int command, const void *indata, int insize,
+	       void *outdata, int outsize)
+{
+	struct i2c_rdwr_ioctl_data data;
+	int ret = -1;
+	int i;
+	uint8_t res_code;
+	uint8_t *req_buf = NULL;
+	uint8_t *resp_buf = NULL;
+	const uint8_t *c;
+	uint8_t *d;
+	uint8_t sum;
+	struct i2c_msg i2c_msg[2];
+
+	if (i2c_fd < 0)
+		return -1;
+
+	if (ioctl(i2c_fd, I2C_SLAVE, EC_I2C_ADDR) < 0) {
+		fprintf(stderr, "Cannot set I2C slave address\n");
+		return -1;
+	}
+
+	i2c_msg[0].addr = EC_I2C_ADDR;
+	i2c_msg[0].flags = 0;
+	i2c_msg[1].addr = EC_I2C_ADDR;
+	i2c_msg[1].flags = I2C_M_RD;
+	data.msgs = i2c_msg;
+	data.nmsgs = 2;
+
+	if (outsize) {
+		/* allocate larger packet
+		 * (one byte for checksum, one for result code)
+		 */
+		resp_buf = calloc(1, outsize + 2);
+		if (!resp_buf)
+			goto done;
+		i2c_msg[1].len = outsize + 2;
+		i2c_msg[1].buf = (char *)resp_buf;
+	} else {
+		i2c_msg[1].len = 1;
+		i2c_msg[1].buf = (char *)&res_code;
+	}
+
+	if (insize) {
+		/* allocate larger packet
+		 * (one byte for checksum, one for command code)
+		 */
+		req_buf = calloc(1, insize + 2);
+		if (!req_buf)
+			goto done;
+		i2c_msg[0].len = insize + 2;
+		i2c_msg[0].buf = (char *)req_buf;
+		req_buf[0] = command;
+
+		debug("i2c req %02x:", command);
+		/* copy message payload and compute checksum */
+		for (i = 0, sum = 0, c = indata; i < insize; i++, c++) {
+			req_buf[i + 1] = *c;
+			sum += *c;
+			debug(" %02x", *c);
+		}
+		debug(", sum=%02x\n", sum);
+		req_buf[insize + 1] = sum;
+	} else {
+		i2c_msg[0].len = 1;
+		i2c_msg[0].buf = (char *)&command; /* nasty cast */
+	}
+
+	/* send command to EC and read answer */
+	ret = ioctl(i2c_fd, I2C_RDWR, &data);
+	if (ret < 0) {
+		fprintf(stderr, "i2c transfer failed: %d (err: %d)\n",
+			ret, errno);
+		goto done;
+	}
+
+	/* check response error code */
+	ret = i2c_msg[1].buf[0];
+	if (ret) {
+		debug("command 0x%02x returned an error %d\n",
+			 command, i2c_msg[1].buf[0]);
+	} else if (outsize) {
+		debug("i2c resp  :");
+		/* copy response packet payload and compute checksum */
+		for (i = 0, sum = 0, d = outdata; i < outsize; i++, d++) {
+			*d = resp_buf[i + 1];
+			sum += *d;
+			debug(" %02x", *d);
+		}
+		debug(", sum=%02x\n", sum);
+
+		if (sum != resp_buf[outsize + 1]) {
+			debug("bad packet checksum\n");
+			ret = -1;
+			goto done;
+		}
+	}
+done:
+	if (resp_buf)
+		free(resp_buf);
+	if (req_buf)
+		free(req_buf);
+	return ret;
+}
+
+
+uint8_t read_mapped_mem8(uint8_t offset)
+{
+	/* Not implemented */
+	return 0xff;
+}
+
+
+uint16_t read_mapped_mem16(uint8_t offset)
+{
+	/* Not implemented */
+	return 0xffff;
+}
+
+
+uint32_t read_mapped_mem32(uint8_t offset)
+{
+	/* Not implemented */
+	return 0xffffffff;
+}
+
+
+int read_mapped_string(uint8_t offset, char *buf)
+{
+	strncpy(buf, "NOT IMPLEMENTED", EC_MEMMAP_TEXT_MAX);
+	return sizeof("NOT IMPLEMENTED");
+}