cros_ec: Add base support for protocol v3
Protocol v2 was shipped with snow, link and spring. Protocol v3 is for
pit and is targetted at SPI operation.
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/misc/cros_ec.c b/drivers/misc/cros_ec.c
index 33b9390..a7716b8 100644
--- a/drivers/misc/cros_ec.c
+++ b/drivers/misc/cros_ec.c
@@ -74,11 +74,174 @@
return csum & 0xff;
}
+/**
+ * Create a request packet for protocol version 3.
+ *
+ * The packet is stored in the device's internal output buffer.
+ *
+ * @param dev CROS-EC device
+ * @param cmd Command to send (EC_CMD_...)
+ * @param cmd_version Version of command to send (EC_VER_...)
+ * @param dout Output data (may be NULL If dout_len=0)
+ * @param dout_len Size of output data in bytes
+ * @return packet size in bytes, or <0 if error.
+ */
+static int create_proto3_request(struct cros_ec_dev *dev,
+ int cmd, int cmd_version,
+ const void *dout, int dout_len)
+{
+ struct ec_host_request *rq = (struct ec_host_request *)dev->dout;
+ int out_bytes = dout_len + sizeof(*rq);
+
+ /* Fail if output size is too big */
+ if (out_bytes > (int)sizeof(dev->dout)) {
+ debug("%s: Cannot send %d bytes\n", __func__, dout_len);
+ return -EC_RES_REQUEST_TRUNCATED;
+ }
+
+ /* Fill in request packet */
+ rq->struct_version = EC_HOST_REQUEST_VERSION;
+ rq->checksum = 0;
+ rq->command = cmd;
+ rq->command_version = cmd_version;
+ rq->reserved = 0;
+ rq->data_len = dout_len;
+
+ /* Copy data after header */
+ memcpy(rq + 1, dout, dout_len);
+
+ /* Write checksum field so the entire packet sums to 0 */
+ rq->checksum = (uint8_t)(-cros_ec_calc_checksum(dev->dout, out_bytes));
+
+ cros_ec_dump_data("out", cmd, dev->dout, out_bytes);
+
+ /* Return size of request packet */
+ return out_bytes;
+}
+
+/**
+ * Prepare the device to receive a protocol version 3 response.
+ *
+ * @param dev CROS-EC device
+ * @param din_len Maximum size of response in bytes
+ * @return maximum expected number of bytes in response, or <0 if error.
+ */
+static int prepare_proto3_response_buffer(struct cros_ec_dev *dev, int din_len)
+{
+ int in_bytes = din_len + sizeof(struct ec_host_response);
+
+ /* Fail if input size is too big */
+ if (in_bytes > (int)sizeof(dev->din)) {
+ debug("%s: Cannot receive %d bytes\n", __func__, din_len);
+ 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 device's internal input buffer.
+ *
+ * @param dev CROS-EC device
+ * @param dinp Returns pointer to response data
+ * @param din_len Maximum size of response in bytes
+ * @return number of bytes of response data, or <0 if error
+ */
+static int handle_proto3_response(struct cros_ec_dev *dev,
+ uint8_t **dinp, int din_len)
+{
+ struct ec_host_response *rs = (struct ec_host_response *)dev->din;
+ int in_bytes;
+ int csum;
+
+ cros_ec_dump_data("in-header", -1, dev->din, sizeof(*rs));
+
+ /* Check input data */
+ if (rs->struct_version != EC_HOST_RESPONSE_VERSION) {
+ debug("%s: EC response version mismatch\n", __func__);
+ return -EC_RES_INVALID_RESPONSE;
+ }
+
+ if (rs->reserved) {
+ debug("%s: EC response reserved != 0\n", __func__);
+ return -EC_RES_INVALID_RESPONSE;
+ }
+
+ if (rs->data_len > din_len) {
+ debug("%s: EC returned too much data\n", __func__);
+ return -EC_RES_RESPONSE_TOO_BIG;
+ }
+
+ cros_ec_dump_data("in-data", -1, dev->din + sizeof(*rs), rs->data_len);
+
+ /* Update in_bytes to actual data size */
+ in_bytes = sizeof(*rs) + rs->data_len;
+
+ /* Verify checksum */
+ csum = cros_ec_calc_checksum(dev->din, in_bytes);
+ if (csum) {
+ debug("%s: EC response checksum invalid: 0x%02x\n", __func__,
+ csum);
+ return -EC_RES_INVALID_CHECKSUM;
+ }
+
+ /* Return error result, if any */
+ if (rs->result)
+ return -(int)rs->result;
+
+ /* If we're still here, set response data pointer and return length */
+ *dinp = (uint8_t *)(rs + 1);
+
+ return rs->data_len;
+}
+
+static int send_command_proto3(struct cros_ec_dev *dev,
+ int cmd, int cmd_version,
+ const void *dout, int dout_len,
+ uint8_t **dinp, int din_len)
+{
+ int out_bytes, in_bytes;
+ int rv;
+
+ /* Create request packet */
+ out_bytes = create_proto3_request(dev, cmd, cmd_version,
+ dout, dout_len);
+ if (out_bytes < 0)
+ return out_bytes;
+
+ /* Prepare response buffer */
+ in_bytes = prepare_proto3_response_buffer(dev, din_len);
+ if (in_bytes < 0)
+ return in_bytes;
+
+ switch (dev->interface) {
+ case CROS_EC_IF_NONE:
+ /* TODO: support protocol 3 for LPC, I2C; for now fall through */
+ default:
+ debug("%s: Unsupported interface\n", __func__);
+ rv = -1;
+ }
+ if (rv < 0)
+ return rv;
+
+ /* Process the response */
+ return handle_proto3_response(dev, dinp, din_len);
+}
+
static int send_command(struct cros_ec_dev *dev, uint8_t cmd, int cmd_version,
const void *dout, int dout_len,
uint8_t **dinp, int din_len)
{
- int ret;
+ int ret = -1;
+
+ /* Handle protocol version 3 support */
+ if (dev->protocol_version == 3) {
+ return send_command_proto3(dev, cmd, cmd_version,
+ dout, dout_len, dinp, din_len);
+ }
switch (dev->interface) {
#ifdef CONFIG_CROS_EC_SPI