Patch set updated for coreboot: 7cc4178 ec/google: Support ChromeOS EC in I2C interface.

[Hung-Te Lin]

Hung-Te Lin ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/3074

-gerrit

commit 7cc417838cb5c3a1ff124800712c6094c1ce7c48
Author: Hung-Te Lin 
Date:   Mon Apr 15 18:27:24 2013 +0800

ec/google: Support ChromeOS EC in I2C interface.

Adds I2C protocol for ChromeOS EC.

Note: I2C interface cannot be automatically probed so the bus and chip number
    must be explicitly set.

Verified by booting Google/Snow, with following console output:
      Google Chrome EC: Hello got back 11223344 status (0)
      Google Chrome EC: version:
         ro: snow_v1.3.108-30f8374
         rw: snow_v1.3.128-e35f60e
        running image: 1

Change-Id: I8023eb96cf477755d277fd7991bdb7d9392f10f7
    Signed-off-by: Hung-Te Lin 
---
 src/ec/google/chromeec/Kconfig      |  17 ++++
 src/ec/google/chromeec/Makefile.inc |   3 +
 src/ec/google/chromeec/ec.c         |   9 ++
 src/ec/google/chromeec/ec.h         |   1 +
 src/ec/google/chromeec/ec_i2c.c     | 159 ++++++++++++++++++++++++++++++++++++
 5 files changed, 189 insertions(+)

diff --git a/src/ec/google/chromeec/Kconfig b/src/ec/google/chromeec/Kconfig
index ce96da7..4fb41e8 100644
--- a/src/ec/google/chromeec/Kconfig
+++ b/src/ec/google/chromeec/Kconfig
@@ -10,6 +10,23 @@ config EC_GOOGLE_API_ROOT
        help
          Path to the ec API file (ec/ec_commands.h).

+config EC_GOOGLE_CHROMEEC_I2C
+	depends on EC_GOOGLE_CHROMEEC
+	bool
+	default y if ARCH_ARMV7
+	help
+	  Google Chrome EC via I2C bus.
+
+config EC_GOOGLE_CHROMEEC_I2C_BUS
+	depends on EC_GOOGLE_CHROMEEC_I2C
+	hex
+	default 4
+
+config EC_GOOGLE_CHROMEEC_I2C_CHIP
+	depends on EC_GOOGLE_CHROMEEC_I2C
+	hex
+	default 0x1e
+
 config EC_GOOGLE_CHROMEEC_LPC
         depends on EC_GOOGLE_CHROMEEC
    bool
diff --git a/src/ec/google/chromeec/Makefile.inc b/src/ec/google/chromeec/Makefile.inc
index 5fb258f..5bc9268 100644
--- a/src/ec/google/chromeec/Makefile.inc
+++ b/src/ec/google/chromeec/Makefile.inc
@@ -1,8 +1,11 @@
 ramstage-y += ec.c
+ramstage-$(CONFIG_EC_GOOGLE_CHROMEEC_I2C) += ec_i2c.c
 ramstage-$(CONFIG_EC_GOOGLE_CHROMEEC_LPC) += ec_lpc.c
 smm-y += ec.c
+smm-$(CONFIG_EC_GOOGLE_CHROMEEC_I2C) += ec_i2c.c
 smm-$(CONFIG_EC_GOOGLE_CHROMEEC_LPC) += ec_lpc.c
 romstage-y += ec.c
+romstage-$(CONFIG_EC_GOOGLE_CHROMEEC_I2C) += ec_i2c.c
 romstage-$(CONFIG_EC_GOOGLE_CHROMEEC_LPC) += ec_lpc.c

CFLAGS += -I $(call strip_quotes,$(CONFIG_EC_GOOGLE_API_ROOT))
diff --git a/src/ec/google/chromeec/ec.c b/src/ec/google/chromeec/ec.c
index 42115be..d94338f 100644
--- a/src/ec/google/chromeec/ec.c
+++ b/src/ec/google/chromeec/ec.c
@@ -33,6 +33,15 @@
 #include "ec_commands.h"
 #include <vendorcode/google/chromeos/chromeos.h>

+uint8_t google_chromeec_calc_checksum(const uint8_t *data, int size)
+{
+	int csum;
+
+	for (csum = 0; size > 0; data++, size--)
+		csum += *data;
+	return (uint8_t)(csum & 0xff);
+}
+
 int google_chromeec_kbbacklight(int percent)
 {
    struct chromeec_command cec_cmd;
diff --git a/src/ec/google/chromeec/ec.h b/src/ec/google/chromeec/ec.h
index f7512d7..3eb555c 100644
--- a/src/ec/google/chromeec/ec.h
+++ b/src/ec/google/chromeec/ec.h
@@ -33,6 +33,7 @@ u16 google_chromeec_get_board_version(void);
 void google_chromeec_init(void);
 #endif

+uint8_t google_chromeec_calc_checksum(const uint8_t *data, int size);
 u32 google_chromeec_get_events_b(void);
 int google_chromeec_kbbacklight(int percent);
 void google_chromeec_post(u8 postcode);
diff --git a/src/ec/google/chromeec/ec_i2c.c b/src/ec/google/chromeec/ec_i2c.c
new file mode 100644
index 0000000..f8e5177
--- /dev/null
+++ b/src/ec/google/chromeec/ec_i2c.c
@@ -0,0 +1,159 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2013 Google Inc.  All rights reserved.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <arch/io.h>
+#include <console/console.h>
+#include <delay.h>
+#include <device/i2c.h>
+#include <stdint.h>
+#include <string.h>
+#include "ec.h"
+#include "ec_commands.h"
+
+/* Command (host->device) format for I2C:
+ *  uint8_t version, cmd, len, data[len], checksum;
+ *
+ * Response (device->host) format for I2C:
+ *  uint8_t response, len, data[len], checksum;
+ *
+ * Note the location of checksum is different from LPC protocol.
+ *
+ * The length is 8 bit so maximum data size is 0xff.
+ * Any I2C command should fit in 0xff + 4 bytes, and max response length
+ * is 0xff + 3 bytes.
+ */
+#define MAX_I2C_DATA_SIZE		(0xff)
+
+typedef struct {
+	uint8_t version;
+	uint8_t command;
+	uint8_t length;
+	uint8_t data[MAX_I2C_DATA_SIZE + 1];
+} EcCommandI2c;
+
+typedef struct {
+	uint8_t response;
+	uint8_t length;
+	uint8_t data[MAX_I2C_DATA_SIZE + 1];
+} EcResponseI2c;
+
+static inline void i2c_dump(int bus, int chip, const uint8_t *data, size_t size)
+{
+#ifdef TRACE_CHROMEEC
+	printk(BIOS_INFO, "i2c: bus=%d, chip=%#x, size=%d, data: ", bus, chip,
+	       size);
+	while (size-- > 0) {
+		printk(BIOS_INFO, "%02X ", *data++);
+	}
+	printk(BIOS_INFO, "\n");
+#endif
+}
+
+static int ec_verify_checksum(const EcResponseI2c *resp)
+{
+	size_t size = sizeof(*resp) - sizeof(resp->data) + resp->length;
+	uint8_t calculated = google_chromeec_calc_checksum(
+			(const uint8_t *)resp, size);
+	uint8_t received = resp->data[resp->length];
+	if (calculated != received) {
+		printk(BIOS_ERR, "%s: unmatch (rx: %#02x, calc: %#02x)\n",
+		       __func__, received, calculated);
+		return 0;
+	}
+	return 1;
+}
+
+static void ec_fill_checksum(EcCommandI2c *cmd)
+{
+	size_t size = sizeof(*cmd) - sizeof(cmd->data) + cmd->length;
+	cmd->data[cmd->length] = google_chromeec_calc_checksum(
+			(const uint8_t *)cmd, size);
+}
+
+int google_chromeec_command(struct chromeec_command *cec_command)
+{
+	EcCommandI2c cmd;
+	EcResponseI2c resp;
+	int bus = CONFIG_EC_GOOGLE_CHROMEEC_I2C_BUS,
+	    chip = CONFIG_EC_GOOGLE_CHROMEEC_I2C_CHIP;
+	size_t size_i2c_cmd = (sizeof(cmd) - sizeof(cmd.data) +
+			       cec_command->cmd_size_in + 1),
+	       size_i2c_resp = (sizeof(resp) - sizeof(resp.data) +
+				cec_command->cmd_size_out + 1);
+
+	if (cec_command->cmd_size_in > MAX_I2C_DATA_SIZE ||
+	    cec_command->cmd_size_out > MAX_I2C_DATA_SIZE) {
+		printk(BIOS_ERR, "%s: command data size too large (%d,%d)\n",
+		       __func__, cec_command->cmd_size_in,
+		       cec_command->cmd_size_out);
+		cec_command->cmd_code = EC_RES_INVALID_PARAM;
+		return 1;
+	}
+
+	/* Construct command. */
+	cmd.version = EC_CMD_VERSION0 + cec_command->cmd_version;
+	cmd.command = cec_command->cmd_code;
+	cmd.length = cec_command->cmd_size_in;
+	memcpy(cmd.data, cec_command->cmd_data_in, cmd.length);
+	ec_fill_checksum(&cmd);
+
+	/* Start I2C communication */
+	i2c_dump(bus, chip, (const uint8_t *)&cmd, size_i2c_cmd);
+	if (i2c_write(bus, chip, 0, 0, (uint8_t *)&cmd, size_i2c_cmd) != 0) {
+		printk(BIOS_ERR, "%s: Cannot complete write to i2c-%d:0x%x\n",
+		       __func__, bus, chip);
+		cec_command->cmd_code = EC_RES_ERROR;
+		return 1;
+	}
+	if (i2c_read(bus, chip, 0, 0, (uint8_t *)&resp, size_i2c_resp) != 0) {
+		printk(BIOS_ERR, "%s: Cannot complete read from i2c-%d:0x%x\n",
+		       __func__, bus, chip);
+		cec_command->cmd_code = EC_RES_ERROR;
+		return 1;
+	}
+
+	/* Verify and return response */
+	cec_command->cmd_code = resp.response;
+	if (resp.response != EC_RES_SUCCESS) {
+		printk(BIOS_DEBUG, "%s: Received bad result code %d\n",
+		       __func__, (int)resp.response);
+		return 1;
+	}
+	if (resp.length > cec_command->cmd_size_out) {
+		printk(BIOS_ERR, "%s: Received len %#02x too large\n",
+		       __func__, (int)resp.length);
+		cec_command->cmd_code = EC_RES_INVALID_RESPONSE;
+		return 1;
+	}
+	if (!ec_verify_checksum(&resp)) {
+		cec_command->cmd_code = EC_RES_INVALID_CHECKSUM;
+		return 1;
+	}
+	cec_command->cmd_size_out = resp.length;
+	memcpy(cec_command->cmd_data_out, resp.data, resp.length);
+	return 0;
+}
+
+#ifndef __PRE_RAM__
+u8 google_chromeec_get_event(void)
+{
+	printk(BIOS_ERR, "%s: not supported.\n", __func__);
+	return 0;
+}
+#endif