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mfd: cros_ec: Add EC transport protocol v4

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Introduce a new transport procotol between EC and host.

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Acked-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Benson Leung <bleung@chromium.org>
Reviewed-by: Fabien Lahoudere <fabien.lahoudere@collabora.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This commit is contained in:
Gwendal Grignou 2019-06-03 11:33:45 -07:00 committed by Lee Jones
parent 03f6896aeb
commit 2908c4ed29
1 changed files with 141 additions and 2 deletions
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143
include/linux/mfd/cros_ec_commands.h
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@ -455,7 +455,10 @@
#define EC_LPC_STATUS_BUSY_MASK \
(EC_LPC_STATUS_FROM_HOST | EC_LPC_STATUS_PROCESSING)
/* Host command response codes */
/*
* Host command response codes (16-bit). Note that response codes should be
* stored in a uint16_t rather than directly in a value of this type.
*/
enum ec_status {
EC_RES_SUCCESS = 0,
EC_RES_INVALID_COMMAND = 1,
@ -471,7 +474,13 @@ enum ec_status {
EC_RES_OVERFLOW = 11, /* Table / data overflow */
EC_RES_INVALID_HEADER = 12, /* Header contains invalid data */
EC_RES_REQUEST_TRUNCATED = 13, /* Didn't get the entire request */
EC_RES_RESPONSE_TOO_BIG = 14 /* Response was too big to handle */
EC_RES_RESPONSE_TOO_BIG = 14, /* Response was too big to handle */
EC_RES_BUS_ERROR = 15, /* Communications bus error */
EC_RES_BUSY = 16, /* Up but too busy. Should retry */
EC_RES_INVALID_HEADER_VERSION = 17, /* Header version invalid */
EC_RES_INVALID_HEADER_CRC = 18, /* Header CRC invalid */
EC_RES_INVALID_DATA_CRC = 19, /* Data CRC invalid */
EC_RES_DUP_UNAVAILABLE = 20, /* Can't resend response */
};
/*
@ -744,6 +753,136 @@ struct ec_host_response {
uint16_t reserved;
} __ec_align4;
/*****************************************************************************/
/*
* Host command protocol V4.
*
* Packets always start with a request or response header. They are followed
* by data_len bytes of data. If the data_crc_present flag is set, the data
* bytes are followed by a CRC-8 of that data, using using x^8 + x^2 + x + 1
* polynomial.
*
* Host algorithm when sending a request q:
*
* 101) tries_left=(some value, e.g. 3);
* 102) q.seq_num++
* 103) q.seq_dup=0
* 104) Calculate q.header_crc.
* 105) Send request q to EC.
* 106) Wait for response r. Go to 201 if received or 301 if timeout.
*
* 201) If r.struct_version != 4, go to 301.
* 202) If r.header_crc mismatches calculated CRC for r header, go to 301.
* 203) If r.data_crc_present and r.data_crc mismatches, go to 301.
* 204) If r.seq_num != q.seq_num, go to 301.
* 205) If r.seq_dup == q.seq_dup, return success.
* 207) If r.seq_dup == 1, go to 301.
* 208) Return error.
*
* 301) If --tries_left <= 0, return error.
* 302) If q.seq_dup == 1, go to 105.
* 303) q.seq_dup = 1
* 304) Go to 104.
*
* EC algorithm when receiving a request q.
* EC has response buffer r, error buffer e.
*
* 101) If q.struct_version != 4, set e.result = EC_RES_INVALID_HEADER_VERSION
* and go to 301
* 102) If q.header_crc mismatches calculated CRC, set e.result =
* EC_RES_INVALID_HEADER_CRC and go to 301
* 103) If q.data_crc_present, calculate data CRC. If that mismatches the CRC
* byte at the end of the packet, set e.result = EC_RES_INVALID_DATA_CRC
* and go to 301.
* 104) If q.seq_dup == 0, go to 201.
* 105) If q.seq_num != r.seq_num, go to 201.
* 106) If q.seq_dup == r.seq_dup, go to 205, else go to 203.
*
* 201) Process request q into response r.
* 202) r.seq_num = q.seq_num
* 203) r.seq_dup = q.seq_dup
* 204) Calculate r.header_crc
* 205) If r.data_len > 0 and data is no longer available, set e.result =
* EC_RES_DUP_UNAVAILABLE and go to 301.
* 206) Send response r.
*
* 301) e.seq_num = q.seq_num
* 302) e.seq_dup = q.seq_dup
* 303) Calculate e.header_crc.
* 304) Send error response e.
*/
/* Version 4 request from host */
struct ec_host_request4 {
/*
* bits 0-3: struct_version: Structure version (=4)
* bit 4: is_response: Is response (=0)
* bits 5-6: seq_num: Sequence number
* bit 7: seq_dup: Sequence duplicate flag
*/
uint8_t fields0;
/*
* bits 0-4: command_version: Command version
* bits 5-6: Reserved (set 0, ignore on read)
* bit 7: data_crc_present: Is data CRC present after data
*/
uint8_t fields1;
/* Command code (EC_CMD_*) */
uint16_t command;
/* Length of data which follows this header (not including data CRC) */
uint16_t data_len;
/* Reserved (set 0, ignore on read) */
uint8_t reserved;
/* CRC-8 of above fields, using x^8 + x^2 + x + 1 polynomial */
uint8_t header_crc;
} __ec_align4;
/* Version 4 response from EC */
struct ec_host_response4 {
/*
* bits 0-3: struct_version: Structure version (=4)
* bit 4: is_response: Is response (=1)
* bits 5-6: seq_num: Sequence number
* bit 7: seq_dup: Sequence duplicate flag
*/
uint8_t fields0;
/*
* bits 0-6: Reserved (set 0, ignore on read)
* bit 7: data_crc_present: Is data CRC present after data
*/
uint8_t fields1;
/* Result code (EC_RES_*) */
uint16_t result;
/* Length of data which follows this header (not including data CRC) */
uint16_t data_len;
/* Reserved (set 0, ignore on read) */
uint8_t reserved;
/* CRC-8 of above fields, using x^8 + x^2 + x + 1 polynomial */
uint8_t header_crc;
} __ec_align4;
/* Fields in fields0 byte */
#define EC_PACKET4_0_STRUCT_VERSION_MASK 0x0f
#define EC_PACKET4_0_IS_RESPONSE_MASK 0x10
#define EC_PACKET4_0_SEQ_NUM_SHIFT 5
#define EC_PACKET4_0_SEQ_NUM_MASK 0x60
#define EC_PACKET4_0_SEQ_DUP_MASK 0x80
/* Fields in fields1 byte */
#define EC_PACKET4_1_COMMAND_VERSION_MASK 0x1f /* (request only) */
#define EC_PACKET4_1_DATA_CRC_PRESENT_MASK 0x80
/*****************************************************************************/
/*
* Notes on commands: