From b2a668b523ee78c56b466300350050924ed59553 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Thu, 27 Feb 2014 13:26:14 -0700 Subject: [PATCH] cros_ec: Implement I2C pass-through The Chrome EC has a feature where you can access its I2C buses through a pass-through arrangement. Add a command to support this, and export the function for it also. Reviewed-by: Vadim Bendebury Signed-off-by: Simon Glass --- drivers/misc/cros_ec.c | 270 ++++++++++++++++++++++++++++++++++++++++- include/cros_ec.h | 14 +++ 2 files changed, 282 insertions(+), 2 deletions(-) diff --git a/drivers/misc/cros_ec.c b/drivers/misc/cros_ec.c index 7e8c58f86a..068373b942 100644 --- a/drivers/misc/cros_ec.c +++ b/drivers/misc/cros_ec.c @@ -1197,6 +1197,87 @@ int cros_ec_decode_ec_flash(const void *blob, struct fdt_cros_ec *config) return 0; } +int cros_ec_i2c_xfer(struct cros_ec_dev *dev, uchar chip, uint addr, + int alen, uchar *buffer, int len, int is_read) +{ + union { + struct ec_params_i2c_passthru p; + uint8_t outbuf[EC_PROTO2_MAX_PARAM_SIZE]; + } params; + union { + struct ec_response_i2c_passthru r; + uint8_t inbuf[EC_PROTO2_MAX_PARAM_SIZE]; + } response; + struct ec_params_i2c_passthru *p = ¶ms.p; + struct ec_response_i2c_passthru *r = &response.r; + struct ec_params_i2c_passthru_msg *msg = p->msg; + uint8_t *pdata; + int read_len, write_len; + int size; + int rv; + + p->port = 0; + + if (alen != 1) { + printf("Unsupported address length %d\n", alen); + return -1; + } + if (is_read) { + read_len = len; + write_len = alen; + p->num_msgs = 2; + } else { + read_len = 0; + write_len = alen + len; + p->num_msgs = 1; + } + + size = sizeof(*p) + p->num_msgs * sizeof(*msg); + if (size + write_len > sizeof(params)) { + puts("Params too large for buffer\n"); + return -1; + } + if (sizeof(*r) + read_len > sizeof(response)) { + puts("Read length too big for buffer\n"); + return -1; + } + + /* Create a message to write the register address and optional data */ + pdata = (uint8_t *)p + size; + msg->addr_flags = chip; + msg->len = write_len; + pdata[0] = addr; + if (!is_read) + memcpy(pdata + 1, buffer, len); + msg++; + + if (read_len) { + msg->addr_flags = chip | EC_I2C_FLAG_READ; + msg->len = read_len; + } + + rv = ec_command(dev, EC_CMD_I2C_PASSTHRU, 0, p, size + write_len, + r, sizeof(*r) + read_len); + if (rv < 0) + return rv; + + /* Parse response */ + if (r->i2c_status & EC_I2C_STATUS_ERROR) { + printf("Transfer failed with status=0x%x\n", r->i2c_status); + return -1; + } + + if (rv < sizeof(*r) + read_len) { + puts("Truncated read response\n"); + return -1; + } + + if (read_len) + memcpy(buffer, r->data, read_len); + + return 0; +} + #ifdef CONFIG_CMD_CROS_EC /** @@ -1252,6 +1333,187 @@ static int do_read_write(struct cros_ec_dev *dev, int is_write, int argc, return 0; } +/** + * get_alen() - Small parser helper function to get address length + * + * Returns the address length. + */ +static uint get_alen(char *arg) +{ + int j; + int alen; + + alen = 1; + for (j = 0; j < 8; j++) { + if (arg[j] == '.') { + alen = arg[j+1] - '0'; + break; + } else if (arg[j] == '\0') { + break; + } + } + return alen; +} + +#define DISP_LINE_LEN 16 + +/* + * TODO(sjg@chromium.org): This code copied almost verbatim from cmd_i2c.c + * so we can remove it later. + */ +static int cros_ec_i2c_md(struct cros_ec_dev *dev, int flag, int argc, + char * const argv[]) +{ + u_char chip; + uint addr, alen, length = 0x10; + int j, nbytes, linebytes; + + if (argc < 2) + return CMD_RET_USAGE; + + if (1 || (flag & CMD_FLAG_REPEAT) == 0) { + /* + * New command specified. + */ + + /* + * I2C chip address + */ + chip = simple_strtoul(argv[0], NULL, 16); + + /* + * I2C data address within the chip. This can be 1 or + * 2 bytes long. Some day it might be 3 bytes long :-). + */ + addr = simple_strtoul(argv[1], NULL, 16); + alen = get_alen(argv[1]); + if (alen > 3) + return CMD_RET_USAGE; + + /* + * If another parameter, it is the length to display. + * Length is the number of objects, not number of bytes. + */ + if (argc > 2) + length = simple_strtoul(argv[2], NULL, 16); + } + + /* + * Print the lines. + * + * We buffer all read data, so we can make sure data is read only + * once. + */ + nbytes = length; + do { + unsigned char linebuf[DISP_LINE_LEN]; + unsigned char *cp; + + linebytes = (nbytes > DISP_LINE_LEN) ? DISP_LINE_LEN : nbytes; + + if (cros_ec_i2c_xfer(dev, chip, addr, alen, linebuf, linebytes, + 1)) + puts("Error reading the chip.\n"); + else { + printf("%04x:", addr); + cp = linebuf; + for (j = 0; j < linebytes; j++) { + printf(" %02x", *cp++); + addr++; + } + puts(" "); + cp = linebuf; + for (j = 0; j < linebytes; j++) { + if ((*cp < 0x20) || (*cp > 0x7e)) + puts("."); + else + printf("%c", *cp); + cp++; + } + putc('\n'); + } + nbytes -= linebytes; + } while (nbytes > 0); + + return 0; +} + +static int cros_ec_i2c_mw(struct cros_ec_dev *dev, int flag, int argc, + char * const argv[]) +{ + uchar chip; + ulong addr; + uint alen; + uchar byte; + int count; + + if ((argc < 3) || (argc > 4)) + return CMD_RET_USAGE; + + /* + * Chip is always specified. + */ + chip = simple_strtoul(argv[0], NULL, 16); + + /* + * Address is always specified. + */ + addr = simple_strtoul(argv[1], NULL, 16); + alen = get_alen(argv[1]); + if (alen > 3) + return CMD_RET_USAGE; + + /* + * Value to write is always specified. + */ + byte = simple_strtoul(argv[2], NULL, 16); + + /* + * Optional count + */ + if (argc == 4) + count = simple_strtoul(argv[3], NULL, 16); + else + count = 1; + + while (count-- > 0) { + if (cros_ec_i2c_xfer(dev, chip, addr++, alen, &byte, 1, 0)) + puts("Error writing the chip.\n"); + /* + * Wait for the write to complete. The write can take + * up to 10mSec (we allow a little more time). + */ +/* + * No write delay with FRAM devices. + */ +#if !defined(CONFIG_SYS_I2C_FRAM) + udelay(11000); +#endif + } + + return 0; +} + +/* Temporary code until we have driver model and can use the i2c command */ +static int cros_ec_i2c_passthrough(struct cros_ec_dev *dev, int flag, + int argc, char * const argv[]) +{ + const char *cmd; + + if (argc < 1) + return CMD_RET_USAGE; + cmd = *argv++; + argc--; + if (0 == strcmp("md", cmd)) + cros_ec_i2c_md(dev, flag, argc, argv); + else if (0 == strcmp("mw", cmd)) + cros_ec_i2c_mw(dev, flag, argc, argv); + else + return CMD_RET_USAGE; + + return 0; +} + static int do_cros_ec(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { struct cros_ec_dev *dev = last_dev; @@ -1495,6 +1757,8 @@ static int do_cros_ec(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) debug("%s: Could not access LDO%d\n", __func__, index); return ret; } + } else if (0 == strcmp("i2c", cmd)) { + ret = cros_ec_i2c_passthrough(dev, flag, argc - 2, argv + 2); } else { return CMD_RET_USAGE; } @@ -1508,7 +1772,7 @@ static int do_cros_ec(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) } U_BOOT_CMD( - crosec, 5, 1, do_cros_ec, + crosec, 6, 1, do_cros_ec, "CROS-EC utility command", "init Re-init CROS-EC (done on startup automatically)\n" "crosec id Read CROS-EC ID\n" @@ -1525,6 +1789,8 @@ U_BOOT_CMD( "crosec vbnvcontext [hexstring] Read [write] VbNvContext from EC\n" "crosec ldo [] Switch/Read LDO state\n" "crosec test run tests on cros_ec\n" - "crosec version Read CROS-EC version" + "crosec version Read CROS-EC version\n" + "crosec i2c md chip address[.0, .1, .2] [# of objects] - read from I2C passthru\n" + "crosec i2c mw chip address[.0, .1, .2] value [count] - write to I2C passthru (fill)" ); #endif diff --git a/include/cros_ec.h b/include/cros_ec.h index 1b7c620905..1e4d8db96b 100644 --- a/include/cros_ec.h +++ b/include/cros_ec.h @@ -501,4 +501,18 @@ int cros_ec_decode_ec_flash(const void *blob, struct fdt_cros_ec *config); */ void cros_ec_check_keyboard(struct cros_ec_dev *dev); +/* + * Tunnel an I2C transfer to the EC + * + * @param dev CROS-EC device + * @param chip Chip address (7-bit I2C address) + * @param addr Register address to read/write + * @param alen Length of register address in bytes + * @param buffer Buffer containing data to read/write + * @param len Length of buffer + * @param is_read 1 if this is a read, 0 if this is a write + */ +int cros_ec_i2c_xfer(struct cros_ec_dev *dev, uchar chip, uint addr, + int alen, uchar *buffer, int len, int is_read); + #endif -- 2.25.1