diff options
Diffstat (limited to 'drivers/misc/cros_ec.c')
| -rw-r--r-- | drivers/misc/cros_ec.c | 165 |
1 files changed, 164 insertions, 1 deletions
diff --git a/drivers/misc/cros_ec.c b/drivers/misc/cros_ec.c index 33b9390d3..a7716b87f 100644 --- a/drivers/misc/cros_ec.c +++ b/drivers/misc/cros_ec.c @@ -74,11 +74,174 @@ int cros_ec_calc_checksum(const uint8_t *data, int size) 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 |