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authorHung-Te Lin <hungte@chromium.org>2013-06-22 11:18:39 +0800
committerStefan Reinauer <stefan.reinauer@coreboot.org>2013-07-10 23:15:50 +0200
commite946f981a4c603d93eced2e0ccf8837fca7c8cd4 (patch)
tree0f40ca757a90b725e41cbdc408d2fb2399a5a0c7 /src/ec/google
parent23fb9979d999a155a2560a9f09f4fcdc1b96e9e7 (diff)
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> Reviewed-on: http://review.coreboot.org/3750 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Diffstat (limited to 'src/ec/google')
-rw-r--r--src/ec/google/chromeec/crosec_proto.c224
-rw-r--r--src/ec/google/chromeec/ec.h2
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 016de8d483..42c7c2e35d 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 13e9f234b1..356d2d215d 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 */