Gabe Black (gabeblack@chromium.org) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/3750
-gerrit
commit cd2f12b4338084f73a549d30201c8c12767e318a Author: Hung-Te Lin hungte@chromium.org Date: Sat Jun 22 11:18:39 2013 +0800
ec/google: Support Chrome EC protocol version 3.
Add the new Chrome EC protocol version 3 to Coreboot.
Note, protocol version 3 is not applied on any bus implementations yet. LPC (x86) and I2C (arm/snow) are still using v2 protocol. The first one to use v3 protocol will be SPI bus (arm/pit). LPC / I2C will be updated to v3 only when they are ready to change.
Change-Id: I3006435295fb509c6351afbb97de0fcedcb1d8c4 Signed-off-by: Hung-Te Lin hungte@chromium.org --- src/ec/google/chromeec/crosec_proto.c | 224 +++++++++++++++++++++++++++++++++- src/ec/google/chromeec/ec.h | 2 +- 2 files changed, 223 insertions(+), 3 deletions(-)
diff --git a/src/ec/google/chromeec/crosec_proto.c b/src/ec/google/chromeec/crosec_proto.c index 016de8d..42c7c2e 100644 --- a/src/ec/google/chromeec/crosec_proto.c +++ b/src/ec/google/chromeec/crosec_proto.c @@ -26,9 +26,229 @@ #include "ec_commands.h" #include "ec_message.h"
+/* Common utilities */ + +/* Dumps EC command / response data into debug output. + * + * @param name Message prefix name. + * @param cmd Command code, or -1 to ignore cmd message. + * @param data Data buffer to print. + * @param len Length of data. + */ +static void cros_ec_dump_data(const char *name, int cmd, const uint8_t *data, + int len) +{ + int i; + + printk(BIOS_DEBUG, "%s: ", name); + if (cmd != -1) + printk(BIOS_DEBUG, "cmd=%#x: ", cmd); + for (i = 0; i < len; i++) + printk(BIOS_DEBUG, "%02x ", data[i]); + printk(BIOS_DEBUG, "\n"); +} + +/* Calculate a simple 8-bit checksum of a data block + * + * @param data Data block to checksum + * @param size Size of data block in bytes + * @return checksum value (0 to 255) + */ +static int cros_ec_calc_checksum(const uint8_t *data, int size) +{ + int csum, i; + + for (i = csum = 0; i < size; i++) + csum += data[i]; + return csum & 0xff; +} + +/* Standard Chrome EC protocol, version 3 */ + +struct ec_command_v3 { + struct ec_host_request header; + uint8_t data[MSG_BYTES]; +}; + +struct ec_response_v3 { + struct ec_host_response header; + uint8_t data[MSG_BYTES]; +}; + +/** + * Create a request packet for protocol version 3. + * + * @param cec_command Command description. + * @param cmd Packed command bit stream. + * @return packet size in bytes, or <0 if error. + */ +static int create_proto3_request(const struct chromeec_command *cec_command, + struct ec_command_v3 *cmd) +{ + struct ec_host_request *rq = &cmd->header; + int out_bytes = cec_command->cmd_size_in + sizeof(*rq); + + /* Fail if output size is too big */ + if (out_bytes > sizeof(*cmd)) { + printk(BIOS_ERR, "%s: Cannot send %d bytes\n", __func__, + cec_command->cmd_size_in); + return -EC_RES_REQUEST_TRUNCATED; + } + + /* Fill in request packet */ + rq->struct_version = EC_HOST_REQUEST_VERSION; + rq->checksum = 0; + rq->command = cec_command->cmd_code; + rq->command_version = cec_command->cmd_version; + rq->reserved = 0; + rq->data_len = cec_command->cmd_size_in; + + /* Copy data after header */ + memcpy(cmd->data, cec_command->cmd_data_in, cec_command->cmd_size_in); + + /* Write checksum field so the entire packet sums to 0 */ + rq->checksum = (uint8_t)(-cros_ec_calc_checksum( + (const uint8_t*)cmd, out_bytes)); + + cros_ec_dump_data("out", rq->command, (const uint8_t *)cmd, out_bytes); + + /* Return size of request packet */ + return out_bytes; +} + +/** + * Prepare the device to receive a protocol version 3 response. + * + * @param cec_command Command description. + * @param resp Response buffer. + * @return maximum expected number of bytes in response, or <0 if error. + */ +static int prepare_proto3_response_buffer( + const struct chromeec_command *cec_command, + struct ec_response_v3 *resp) +{ + int in_bytes = cec_command->cmd_size_out + sizeof(resp->header); + + /* Fail if input size is too big */ + if (in_bytes > sizeof(*resp)) { + printk(BIOS_ERR, "%s: Cannot receive %d bytes\n", __func__, + cec_command->cmd_size_out); + return -EC_RES_RESPONSE_TOO_BIG; + } + + /* Return expected size of response packet */ + return in_bytes; +} + +/** + * Handle a protocol version 3 response packet. + * + * The packet must already be stored in the response buffer. + * + * @param resp Response buffer. + * @param cec_command Command structure to receive valid response. + * @return number of bytes of response data, or <0 if error + */ +static int handle_proto3_response(struct ec_response_v3 *resp, + struct chromeec_command *cec_command) +{ + struct ec_host_response *rs = &resp->header; + int in_bytes; + int csum; + + cros_ec_dump_data("in-header", -1, (const uint8_t*)rs, sizeof(*rs)); + + /* Check input data */ + if (rs->struct_version != EC_HOST_RESPONSE_VERSION) { + printk(BIOS_ERR, "%s: EC response version mismatch\n", __func__); + return -EC_RES_INVALID_RESPONSE; + } + + if (rs->reserved) { + printk(BIOS_ERR, "%s: EC response reserved != 0\n", __func__); + return -EC_RES_INVALID_RESPONSE; + } + + if (rs->data_len > sizeof(resp->data) || + rs->data_len > cec_command->cmd_size_out) { + printk(BIOS_ERR, "%s: EC returned too much data\n", __func__); + return -EC_RES_RESPONSE_TOO_BIG; + } + + cros_ec_dump_data("in-data", -1, resp->data, rs->data_len); + + /* Update in_bytes to actual data size */ + in_bytes = sizeof(*rs) + rs->data_len; + + /* Verify checksum */ + csum = cros_ec_calc_checksum((const uint8_t *)resp, in_bytes); + if (csum) { + printk(BIOS_ERR, "%s: EC response checksum invalid: 0x%02x\n", + __func__, csum); + return -EC_RES_INVALID_CHECKSUM; + } + + /* Return raw response. */ + cec_command->cmd_code = rs->result; + cec_command->cmd_size_out = rs->data_len; + memcpy(cec_command->cmd_data_out, resp->data, rs->data_len); + + /* Return error result, if any */ + if (rs->result) { + printk(BIOS_ERR, "%s: EC response with error code: %d\n", + __func__, rs->result); + return -(int)rs->result; + } + + return rs->data_len; +} + +static int send_command_proto3(struct chromeec_command *cec_command, + crosec_io_t crosec_io, void *context) +{ + int out_bytes, in_bytes; + int rv; + struct ec_command_v3 cmd = { {0}, }; + struct ec_response_v3 resp = { {0}, }; + + /* Create request packet */ + out_bytes = create_proto3_request(cec_command, &cmd); + if (out_bytes < 0) { + return out_bytes; + } + + /* Prepare response buffer */ + in_bytes = prepare_proto3_response_buffer(cec_command, &resp); + if (in_bytes < 0) { + return in_bytes; + } + + rv = crosec_io((uint8_t *)&cmd, out_bytes, (uint8_t *)&resp, in_bytes, + context); + if (rv != 0) { + printk(BIOS_ERR, "%s: failed to complete I/O: Err = %#x.", + __func__, rv >= 0 ? rv : -rv); + return -EC_RES_ERROR; + } + + /* Process the response */ + return handle_proto3_response(&resp, cec_command); +} + +static int crosec_command_proto_v3(struct chromeec_command *cec_command, + crosec_io_t crosec_io, void *context) +{ + int rv = send_command_proto3(cec_command, crosec_io, context); + if (rv < 0) { + cec_command->cmd_code = rv; + return 1; + } + return 0; +} + int crosec_command_proto(struct chromeec_command *cec_command, crosec_io_t crosec_io, void *context) { - // TODO(hungte) Add v3 protocol. - return -1; + // TODO(hungte) Detect and fallback to v2 if we need. + return crosec_command_proto_v3(cec_command, crosec_io, context); } diff --git a/src/ec/google/chromeec/ec.h b/src/ec/google/chromeec/ec.h index 13e9f23..356d2d2 100644 --- a/src/ec/google/chromeec/ec.h +++ b/src/ec/google/chromeec/ec.h @@ -53,7 +53,7 @@ int google_chromeec_set_usb_charge_mode(u8 port_id, enum usb_charge_mode mode);
/* internal structure to send a command to the EC and wait for response. */ struct chromeec_command { - uint8_t cmd_code; /* command code in, status out */ + uint16_t cmd_code; /* command code in, status out */ uint8_t cmd_version; /* command version */ const void* cmd_data_in; /* command data, if any */ void* cmd_data_out; /* command response, if any */