[U-Boot] [PATCH v2 20/31] cros_ec: Implement I2C pass-through
Simon Glass
sjg at chromium.org
Thu Feb 27 21:26:14 CET 2014
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 <vbendeb at google.com>
Signed-off-by: Simon Glass <sjg at chromium.org>
---
Changes in v2: None
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 7e8c58f..068373b 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 at 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 <idx> [<state>] 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 1b7c620..1e4d8db 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
--
1.9.0.279.gdc9e3eb
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