Commit 68dbac0a authored by Ben Walsh's avatar Ben Walsh Committed by Tzung-Bi Shih
Browse files

platform/chrome: cros_ec_lpc: MEC access can return error code 



cros_ec_lpc_io_bytes_mec was returning a u8 checksum of all bytes
read/written, which didn't leave room to indicate errors. Change this
u8 to an int where negative values indicate an error, and non-negative
values are the checksum as before.

Tested-by: default avatarDustin L. Howett <dustin@howett.net>
Signed-off-by: default avatarBen Walsh <ben@jubnut.com>
Link: https://lore.kernel.org/r/20240605063351.14836-2-ben@jubnut.com


Signed-off-by: default avatarTzung-Bi Shih <tzungbi@kernel.org>
parent 106d6739

drivers/platform/chrome/cros_ec_lpc.c

+89 −41
Original line number Diff line number Diff line
@@ -62,14 +62,16 @@ struct cros_ec_lpc { 


/**

 * struct lpc_driver_ops - LPC driver operations

 * @read: Copy length bytes from EC address offset into buffer dest. Returns

 *        the 8-bit checksum of all bytes read.

 * @write: Copy length bytes from buffer msg into EC address offset. Returns

 *         the 8-bit checksum of all bytes written.

 * @read: Copy length bytes from EC address offset into buffer dest.

 *        Returns a negative error code on error, or the 8-bit checksum

 *        of all bytes read.

 * @write: Copy length bytes from buffer msg into EC address offset.

 *         Returns a negative error code on error, or the 8-bit checksum

 *         of all bytes written.

 */

struct lpc_driver_ops {

	u8 (*read)(unsigned int offset, unsigned int length, u8 *dest);

	u8 (*write)(unsigned int offset, unsigned int length, const u8 *msg);

	int (*read)(unsigned int offset, unsigned int length, u8 *dest);

	int (*write)(unsigned int offset, unsigned int length, const u8 *msg);

};



static struct lpc_driver_ops cros_ec_lpc_ops = { };
@@ -78,10 +80,10 @@ static struct lpc_driver_ops cros_ec_lpc_ops = { }; 
 * A generic instance of the read function of struct lpc_driver_ops, used for

 * the LPC EC.

 */

static u8 cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length,

static int cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length,

				  u8 *dest)

{

	int sum = 0;

	u8 sum = 0;

	int i;



	for (i = 0; i < length; ++i) {
@@ -97,10 +99,10 @@ static u8 cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length, 
 * A generic instance of the write function of struct lpc_driver_ops, used for

 * the LPC EC.

 */

static u8 cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length,

static int cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length,

				   const u8 *msg)

{

	int sum = 0;

	u8 sum = 0;

	int i;



	for (i = 0; i < length; ++i) {
@@ -116,7 +118,7 @@ static u8 cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length, 
 * An instance of the read function of struct lpc_driver_ops, used for the

 * MEC variant of LPC EC.

 */

static u8 cros_ec_lpc_mec_read_bytes(unsigned int offset, unsigned int length,

static int cros_ec_lpc_mec_read_bytes(unsigned int offset, unsigned int length,

				      u8 *dest)

{

	int in_range = cros_ec_lpc_mec_in_range(offset, length);
@@ -135,7 +137,7 @@ static u8 cros_ec_lpc_mec_read_bytes(unsigned int offset, unsigned int length, 
 * An instance of the write function of struct lpc_driver_ops, used for the

 * MEC variant of LPC EC.

 */

static u8 cros_ec_lpc_mec_write_bytes(unsigned int offset, unsigned int length,

static int cros_ec_lpc_mec_write_bytes(unsigned int offset, unsigned int length,

				       const u8 *msg)

{

	int in_range = cros_ec_lpc_mec_in_range(offset, length);
@@ -154,11 +156,14 @@ static int ec_response_timed_out(void) 
{

	unsigned long one_second = jiffies + HZ;

	u8 data;

	int ret;



	usleep_range(200, 300);

	do {

		if (!(cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_CMD, 1, &data) &

		    EC_LPC_STATUS_BUSY_MASK))

		ret = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_CMD, 1, &data);

		if (ret < 0)

			return ret;

		if (!(data & EC_LPC_STATUS_BUSY_MASK))

			return 0;

		usleep_range(100, 200);

	} while (time_before(jiffies, one_second));
@@ -179,28 +184,41 @@ static int cros_ec_pkt_xfer_lpc(struct cros_ec_device *ec, 
		goto done;



	/* Write buffer */

	cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_PACKET, ret, ec->dout);

	ret = cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_PACKET, ret, ec->dout);

	if (ret < 0)

		goto done;



	/* Here we go */

	sum = EC_COMMAND_PROTOCOL_3;

	cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_CMD, 1, &sum);

	ret = cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_CMD, 1, &sum);

	if (ret < 0)

		goto done;



	if (ec_response_timed_out()) {

	ret = ec_response_timed_out();

	if (ret < 0)

		goto done;

	if (ret) {

		dev_warn(ec->dev, "EC response timed out\n");

		ret = -EIO;

		goto done;

	}



	/* Check result */

	msg->result = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_DATA, 1, &sum);

	ret = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_DATA, 1, &sum);

	if (ret < 0)

		goto done;

	msg->result = ret;

	ret = cros_ec_check_result(ec, msg);

	if (ret)

		goto done;



	/* Read back response */

	dout = (u8 *)&response;

	sum = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_PACKET, sizeof(response),

	ret = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_PACKET, sizeof(response),

				   dout);

	if (ret < 0)

		goto done;

	sum = ret;



	msg->result = response.result;
@@ -213,9 +231,12 @@ static int cros_ec_pkt_xfer_lpc(struct cros_ec_device *ec, 
	}



	/* Read response and process checksum */

	sum += cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_PACKET +

	ret = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_PACKET +

				   sizeof(response), response.data_len,

				   msg->data);

	if (ret < 0)

		goto done;

	sum += ret;



	if (sum) {

		dev_err(ec->dev,
@@ -255,32 +276,47 @@ static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec, 
	sum = msg->command + args.flags + args.command_version + args.data_size;



	/* Copy data and update checksum */

	sum += cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_PARAM, msg->outsize,

	ret = cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_PARAM, msg->outsize,

				    msg->data);

	if (ret < 0)

		goto done;

	sum += ret;



	/* Finalize checksum and write args */

	args.checksum = sum;

	cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_ARGS, sizeof(args),

	ret = cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_ARGS, sizeof(args),

				    (u8 *)&args);

	if (ret < 0)

		goto done;



	/* Here we go */

	sum = msg->command;

	cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_CMD, 1, &sum);

	ret = cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_CMD, 1, &sum);

	if (ret < 0)

		goto done;



	if (ec_response_timed_out()) {

	ret = ec_response_timed_out();

	if (ret < 0)

		goto done;

	if (ret) {

		dev_warn(ec->dev, "EC response timed out\n");

		ret = -EIO;

		goto done;

	}



	/* Check result */

	msg->result = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_DATA, 1, &sum);

	ret = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_DATA, 1, &sum);

	if (ret < 0)

		goto done;

	msg->result = ret;

	ret = cros_ec_check_result(ec, msg);

	if (ret)

		goto done;



	/* Read back args */

	cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_ARGS, sizeof(args), (u8 *)&args);

	ret = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_ARGS, sizeof(args), (u8 *)&args);

	if (ret < 0)

		goto done;



	if (args.data_size > msg->insize) {

		dev_err(ec->dev,
@@ -294,8 +330,11 @@ static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec, 
	sum = msg->command + args.flags + args.command_version + args.data_size;



	/* Read response and update checksum */

	sum += cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_PARAM, args.data_size,

	ret = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_PARAM, args.data_size,

				   msg->data);

	if (ret < 0)

		goto done;

	sum += ret;



	/* Verify checksum */

	if (args.checksum != sum) {
@@ -320,19 +359,24 @@ static int cros_ec_lpc_readmem(struct cros_ec_device *ec, unsigned int offset, 
	int i = offset;

	char *s = dest;

	int cnt = 0;

	int ret;



	if (offset >= EC_MEMMAP_SIZE - bytes)

		return -EINVAL;



	/* fixed length */

	if (bytes) {

		cros_ec_lpc_ops.read(ec_lpc->mmio_memory_base + offset, bytes, s);

		ret = cros_ec_lpc_ops.read(ec_lpc->mmio_memory_base + offset, bytes, s);

		if (ret < 0)

			return ret;

		return bytes;

	}



	/* string */

	for (; i < EC_MEMMAP_SIZE; i++, s++) {

		cros_ec_lpc_ops.read(ec_lpc->mmio_memory_base + i, 1, s);

		ret = cros_ec_lpc_ops.read(ec_lpc->mmio_memory_base + i, 1, s);

		if (ret < 0)

			return ret;

		cnt++;

		if (!*s)

			break;
@@ -425,7 +469,9 @@ static int cros_ec_lpc_probe(struct platform_device *pdev) 
	 */

	cros_ec_lpc_ops.read = cros_ec_lpc_mec_read_bytes;

	cros_ec_lpc_ops.write = cros_ec_lpc_mec_write_bytes;

	cros_ec_lpc_ops.read(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID, 2, buf);

	ret = cros_ec_lpc_ops.read(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID, 2, buf);

	if (ret < 0)

		return ret;

	if (buf[0] != 'E' || buf[1] != 'C') {

		if (!devm_request_region(dev, ec_lpc->mmio_memory_base, EC_MEMMAP_SIZE,

					 dev_name(dev))) {
@@ -436,8 +482,10 @@ static int cros_ec_lpc_probe(struct platform_device *pdev) 
		/* Re-assign read/write operations for the non MEC variant */

		cros_ec_lpc_ops.read = cros_ec_lpc_read_bytes;

		cros_ec_lpc_ops.write = cros_ec_lpc_write_bytes;

		cros_ec_lpc_ops.read(ec_lpc->mmio_memory_base + EC_MEMMAP_ID, 2,

		ret = cros_ec_lpc_ops.read(ec_lpc->mmio_memory_base + EC_MEMMAP_ID, 2,

					   buf);

		if (ret < 0)

			return ret;

		if (buf[0] != 'E' || buf[1] != 'C') {

			dev_err(dev, "EC ID not detected\n");

			return -ENODEV;

drivers/platform/chrome/cros_ec_lpc_mec.c

+5 −4
Original line number Diff line number Diff line
@@ -67,9 +67,10 @@ int cros_ec_lpc_mec_in_range(unsigned int offset, unsigned int length) 
 * @length:  Number of bytes to read / write

 * @buf:     Destination / source buffer

 *

 * Return: 8-bit checksum of all bytes read / written

 * @return:  A negative error code on error, or 8-bit checksum of all

 *           bytes read / written

 */

u8 cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,

int cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,

			     unsigned int offset, unsigned int length,

			     u8 *buf)

{

drivers/platform/chrome/cros_ec_lpc_mec.h

+4 −3
Original line number Diff line number Diff line
@@ -64,9 +64,10 @@ int cros_ec_lpc_mec_in_range(unsigned int offset, unsigned int length); 
 * @length:  Number of bytes to read / write

 * @buf:     Destination / source buffer

 *

 * @return 8-bit checksum of all bytes read / written

 * @return:  A negative error code on error, or 8-bit checksum of all

 *           bytes read / written

 */

u8 cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,

int cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,

			     unsigned int offset, unsigned int length, u8 *buf);



#endif /* __CROS_EC_LPC_MEC_H */

drivers/platform/chrome/wilco_ec/mailbox.c

+14 −8
Original line number Diff line number Diff line
@@ -117,13 +117,17 @@ static int wilco_ec_transfer(struct wilco_ec_device *ec, 
			     struct wilco_ec_request *rq)

{

	struct wilco_ec_response *rs;

	u8 checksum;

	int ret;

	u8 flag;



	/* Write request header, then data */

	cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, 0, sizeof(*rq), (u8 *)rq);

	cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, sizeof(*rq), msg->request_size,

	ret = cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, 0, sizeof(*rq), (u8 *)rq);

	if (ret < 0)

		return ret;

	ret = cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, sizeof(*rq), msg->request_size,

				       msg->request_data);

	if (ret < 0)

		return ret;



	/* Start the command */

	outb(EC_MAILBOX_START_COMMAND, ec->io_command->start);
@@ -149,10 +153,12 @@ static int wilco_ec_transfer(struct wilco_ec_device *ec, 


	/* Read back response */

	rs = ec->data_buffer;

	checksum = cros_ec_lpc_io_bytes_mec(MEC_IO_READ, 0,

	ret = cros_ec_lpc_io_bytes_mec(MEC_IO_READ, 0,

				       sizeof(*rs) + EC_MAILBOX_DATA_SIZE,

				       (u8 *)rs);

	if (checksum) {

	if (ret < 0)

		return ret;

	if (ret) {

		dev_dbg(ec->dev, "bad packet checksum 0x%02x\n", rs->checksum);

		return -EBADMSG;

	}