diff options
Diffstat (limited to 'src/ec/google/chromeec/ec_i2c.c')
| -rw-r--r-- | src/ec/google/chromeec/ec_i2c.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/src/ec/google/chromeec/ec_i2c.c b/src/ec/google/chromeec/ec_i2c.c new file mode 100644 index 0000000000..a13dde6a7b --- /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; + int 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:%#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:%#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 |