Commit 2908c4ed authored by Gwendal Grignou's avatar Gwendal Grignou Committed by Lee Jones
Browse files

mfd: cros_ec: Add EC transport protocol v4 



Introduce a new transport procotol between EC and host.

Signed-off-by: default avatarGwendal Grignou <gwendal@chromium.org>
Acked-by: default avatarEnric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: default avatarBenson Leung <bleung@chromium.org>
Reviewed-by: default avatarFabien Lahoudere <fabien.lahoudere@collabora.com>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
parent 03f6896a

include/linux/mfd/cros_ec_commands.h

+141 −2
Original line number Diff line number Diff line
@@ -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:

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