Re: [PATCH v3 4/7] mfd: cros_ec: add proto v3 skeleton

Lee Jones
2015-05-27T08:39:52Z

On Fri, 22 May 2015, Javier Martinez Canillas wrote:

> From: Stephen Barber <smbarber@chromium.org>
>
> Add support in cros_ec.c to handle EC host command protocol v3.
> For v3+, probe for maximum shared protocol version and max
> request, response, and passthrough sizes. For now, this will
> always fall back to v2, since there is no bus-specific code
> for handling proto v3 packets.
>
> Signed-off-by: Stephen Barber <smbarber@chromium.org>
> Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
> Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
> Tested-by: Gwendal Grignou <gwendal@chromium.org>
> ---
>
> Changes since v2:
> - Add the helpers to the drivers/platform/chrome/cros_ec_proto.c driver
> instead of drivers/mfd/cros_ec.c. Suggested by Lee Jones.
> - Rename the proto probe functions for proto_query since probe has a
> special meaning in Linux so is confusing.
>
> Changes since v1:
> - Squash change https://chromium-review.googlesource.com/#/c/262870/ in
> the patch. Suggested by Gwendal Grignou
> - Add Reviewed-by and Tested-by tags from Gwendal Grignou
> ---
> drivers/mfd/cros_ec.c | 23 ++-
> drivers/mfd/cros_ec_i2c.c | 4 +
> drivers/mfd/cros_ec_spi.c | 7 +-

Acked-by: Lee Jones <lee.jones@linaro.org>

> drivers/platform/chrome/cros_ec_lpc.c | 4 +
> drivers/platform/chrome/cros_ec_proto.c | 339 ++++++++++++++++++++++++++++----
> include/linux/mfd/cros_ec.h | 28 ++-
> 6 files changed, 355 insertions(+), 50 deletions(-)
>
> diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
> index d857f6a2b57b..08d82bfc5268 100644
> --- a/drivers/mfd/cros_ec.c
> +++ b/drivers/mfd/cros_ec.c
> @@ -36,19 +36,22 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
> struct device *dev = ec_dev->dev;
> int err = 0;
>
> - if (ec_dev->din_size) {
> - ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
> - if (!ec_dev->din)
> - return -ENOMEM;
> - }
> - if (ec_dev->dout_size) {
> - ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
> - if (!ec_dev->dout)
> - return -ENOMEM;
> - }
> + ec_dev->max_request = sizeof(struct ec_params_hello);
> + ec_dev->max_response = sizeof(struct ec_response_get_protocol_info);
> + ec_dev->max_passthru = 0;
> +
> + ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
> + if (!ec_dev->din)
> + return -ENOMEM;
> +
> + ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
> + if (!ec_dev->dout)
> + return -ENOMEM;
>
> mutex_init(&ec_dev->lock);
>
> + cros_ec_query_all(ec_dev);
> +
> err = mfd_add_devices(dev, 0, cros_devs,
> ARRAY_SIZE(cros_devs),
> NULL, ec_dev->irq, NULL);
> diff --git a/drivers/mfd/cros_ec_i2c.c b/drivers/mfd/cros_ec_i2c.c
> index fbf7819f5de5..b400bfa2772a 100644
> --- a/drivers/mfd/cros_ec_i2c.c
> +++ b/drivers/mfd/cros_ec_i2c.c
> @@ -143,8 +143,12 @@ static int cros_ec_i2c_probe(struct i2c_client *client,
> ec_dev->priv = client;
> ec_dev->irq = client->irq;
> ec_dev->cmd_xfer = cros_ec_cmd_xfer_i2c;
> + ec_dev->pkt_xfer = NULL;
> ec_dev->ec_name = client->name;
> ec_dev->phys_name = client->adapter->name;
> + ec_dev->din_size = sizeof(struct ec_host_response) +
> + sizeof(struct ec_response_get_protocol_info);
> + ec_dev->dout_size = sizeof(struct ec_host_request);
>
> err = cros_ec_register(ec_dev);
> if (err) {
> diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c
> index 573730fec947..04da2f288ef8 100644
> --- a/drivers/mfd/cros_ec_spi.c
> +++ b/drivers/mfd/cros_ec_spi.c
> @@ -361,10 +361,13 @@ static int cros_ec_spi_probe(struct spi_device *spi)
> ec_dev->priv = ec_spi;
> ec_dev->irq = spi->irq;
> ec_dev->cmd_xfer = cros_ec_cmd_xfer_spi;
> + ec_dev->pkt_xfer = NULL;
> ec_dev->ec_name = ec_spi->spi->modalias;
> ec_dev->phys_name = dev_name(&ec_spi->spi->dev);
> - ec_dev->din_size = EC_MSG_BYTES + EC_MSG_PREAMBLE_COUNT;
> - ec_dev->dout_size = EC_MSG_BYTES;
> + ec_dev->din_size = EC_MSG_PREAMBLE_COUNT +
> + sizeof(struct ec_host_response) +
> + sizeof(struct ec_response_get_protocol_info);
> + ec_dev->dout_size = sizeof(struct ec_host_request);
>
> err = cros_ec_register(ec_dev);
> if (err) {
> diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c
> index 4c7f0df33bf8..05aeb559275f 100644
> --- a/drivers/platform/chrome/cros_ec_lpc.c
> +++ b/drivers/platform/chrome/cros_ec_lpc.c
> @@ -215,7 +215,11 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
> ec_dev->ec_name = pdev->name;
> ec_dev->phys_name = dev_name(dev);
> ec_dev->cmd_xfer = cros_ec_cmd_xfer_lpc;
> + ec_dev->pkt_xfer = NULL;
> ec_dev->cmd_readmem = cros_ec_lpc_readmem;
> + ec_dev->din_size = sizeof(struct ec_host_response) +
> + sizeof(struct ec_response_get_protocol_info);
> + ec_dev->dout_size = sizeof(struct ec_host_request);
>
> ret = cros_ec_register(ec_dev);
> if (ret) {
> diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
> index 58e98a24fd08..990308ca384f 100644
> --- a/drivers/platform/chrome/cros_ec_proto.c
> +++ b/drivers/platform/chrome/cros_ec_proto.c
> @@ -22,11 +22,100 @@
>
> #define EC_COMMAND_RETRIES 50
>
> +static int prepare_packet(struct cros_ec_device *ec_dev,
> + struct cros_ec_command *msg)
> +{
> + struct ec_host_request *request;
> + u8 *out;
> + int i;
> + u8 csum = 0;
> +
> + BUG_ON(ec_dev->proto_version != EC_HOST_REQUEST_VERSION);
> + BUG_ON(msg->outsize + sizeof(*request) > ec_dev->dout_size);
> +
> + out = ec_dev->dout;
> + request = (struct ec_host_request *)out;
> + request->struct_version = EC_HOST_REQUEST_VERSION;
> + request->checksum = 0;
> + request->command = msg->command;
> + request->command_version = msg->version;
> + request->reserved = 0;
> + request->data_len = msg->outsize;
> +
> + for (i = 0; i < sizeof(*request); i++)
> + csum += out[i];
> +
> + /* Copy data and update checksum */
> + memcpy(out + sizeof(*request), msg->data, msg->outsize);
> + for (i = 0; i < msg->outsize; i++)
> + csum += msg->data[i];
> +
> + request->checksum = -csum;
> +
> + return sizeof(*request) + msg->outsize;
> +}
> +
> +static int send_command(struct cros_ec_device *ec_dev,
> + struct cros_ec_command *msg)
> +{
> + int ret;
> +
> + if (ec_dev->proto_version > 2)
> + ret = ec_dev->pkt_xfer(ec_dev, msg);
> + else
> + ret = ec_dev->cmd_xfer(ec_dev, msg);
> +
> + if (msg->result == EC_RES_IN_PROGRESS) {
> + int i;
> + struct cros_ec_command *status_msg;
> + struct ec_response_get_comms_status *status;
> +
> + status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status),
> + GFP_KERNEL);
> + if (!status_msg)
> + return -ENOMEM;
> +
> + status_msg->version = 0;
> + status_msg->command = EC_CMD_GET_COMMS_STATUS;
> + status_msg->insize = sizeof(*status);
> + status_msg->outsize = 0;
> +
> + /*
> + * Query the EC's status until it's no longer busy or
> + * we encounter an error.
> + */
> + for (i = 0; i < EC_COMMAND_RETRIES; i++) {
> + usleep_range(10000, 11000);
> +
> + ret = ec_dev->cmd_xfer(ec_dev, status_msg);
> + if (ret < 0)
> + break;
> +
> + msg->result = status_msg->result;
> + if (status_msg->result != EC_RES_SUCCESS)
> + break;
> +
> + status = (struct ec_response_get_comms_status *)
> + status_msg->data;
> + if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
> + break;
> + }
> +
> + kfree(status_msg);
> + }
> +
> + return ret;
> +}
> +
> int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
> struct cros_ec_command *msg)
> {
> - uint8_t *out;
> - int csum, i;
> + u8 *out;
> + u8 csum;
> + int i;
> +
> + if (ec_dev->proto_version > 2)
> + return prepare_packet(ec_dev, msg);
>
> BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE);
> out = ec_dev->dout;
> @@ -36,7 +125,7 @@ int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
> csum = out[0] + out[1] + out[2];
> for (i = 0; i < msg->outsize; i++)
> csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i];
> - out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = (uint8_t)(csum & 0xff);
> + out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = csum;
>
> return EC_MSG_TX_PROTO_BYTES + msg->outsize;
> }
> @@ -60,54 +149,232 @@ int cros_ec_check_result(struct cros_ec_device *ec_dev,
> }
> EXPORT_SYMBOL(cros_ec_check_result);
>
> -int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
> - struct cros_ec_command *msg)
> +static int cros_ec_host_command_proto_query(struct cros_ec_device *ec_dev,
> + int devidx,
> + struct cros_ec_command *msg)
> {
> + /*
> + * Try using v3+ to query for supported protocols. If this
> + * command fails, fall back to v2. Returns the highest protocol
> + * supported by the EC.
> + * Also sets the max request/response/passthru size.
> + */
> int ret;
>
> - mutex_lock(&ec_dev->lock);
> - ret = ec_dev->cmd_xfer(ec_dev, msg);
> - if (msg->result == EC_RES_IN_PROGRESS) {
> - int i;
> - struct cros_ec_command *status_msg;
> - struct ec_response_get_comms_status *status;
> + if (!ec_dev->pkt_xfer)
> + return -EPROTONOSUPPORT;
>
> - status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status),
> - GFP_KERNEL);
> - if (!status_msg) {
> - ret = -ENOMEM;
> - goto exit;
> - }
> + memset(msg, 0, sizeof(*msg));
> + msg->command = EC_CMD_PASSTHRU_OFFSET(devidx) | EC_CMD_GET_PROTOCOL_INFO;
> + msg->insize = sizeof(struct ec_response_get_protocol_info);
>
> - status_msg->version = 0;
> - status_msg->command = EC_CMD_GET_COMMS_STATUS;
> - status_msg->insize = sizeof(*status);
> - status_msg->outsize = 0;
> + ret = send_command(ec_dev, msg);
> +
> + if (ret < 0) {
> + dev_dbg(ec_dev->dev,
> + "failed to check for EC[%d] protocol version: %d\n",
> + devidx, ret);
> + return ret;
> + }
> +
> + if (devidx > 0 && msg->result == EC_RES_INVALID_COMMAND)
> + return -ENODEV;
> + else if (msg->result != EC_RES_SUCCESS)
> + return msg->result;
> +
> + return 0;
> +}
> +
> +static int cros_ec_host_command_proto_query_v2(struct cros_ec_device *ec_dev)
> +{
> + struct cros_ec_command *msg;
> + struct ec_params_hello *hello_params;
> + struct ec_response_hello *hello_response;
> + int ret;
> + int len = max(sizeof(*hello_params), sizeof(*hello_response));
> +
> + msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL);
> + if (!msg)
> + return -ENOMEM;
> +
> + msg->version = 0;
> + msg->command = EC_CMD_HELLO;
> + hello_params = (struct ec_params_hello *)msg->data;
> + msg->outsize = sizeof(*hello_params);
> + hello_response = (struct ec_response_hello *)msg->data;
> + msg->insize = sizeof(*hello_response);
> +
> + hello_params->in_data = 0xa0b0c0d0;
> +
> + ret = send_command(ec_dev, msg);
> +
> + if (ret < 0) {
> + dev_dbg(ec_dev->dev,
> + "EC failed to respond to v2 hello: %d\n",
> + ret);
> + goto exit;
> + } else if (msg->result != EC_RES_SUCCESS) {
> + dev_err(ec_dev->dev,
> + "EC responded to v2 hello with error: %d\n",
> + msg->result);
> + ret = msg->result;
> + goto exit;
> + } else if (hello_response->out_data != 0xa1b2c3d4) {
> + dev_err(ec_dev->dev,
> + "EC responded to v2 hello with bad result: %u\n",
> + hello_response->out_data);
> + ret = -EBADMSG;
> + goto exit;
> + }
> +
> + ret = 0;
> +
> + exit:
> + kfree(msg);
> + return ret;
> +}
> +
> +int cros_ec_query_all(struct cros_ec_device *ec_dev)
> +{
> + struct device *dev = ec_dev->dev;
> + struct cros_ec_command *proto_msg;
> + struct ec_response_get_protocol_info *proto_info;
> + int ret;
> +
> + proto_msg = kzalloc(sizeof(*proto_msg) + sizeof(*proto_info),
> + GFP_KERNEL);
> + if (!proto_msg)
> + return -ENOMEM;
> +
> + /* First try sending with proto v3. */
> + ec_dev->proto_version = 3;
> + ret = cros_ec_host_command_proto_query(ec_dev, 0, proto_msg);
> +
> + if (ret == 0) {
> + proto_info = (struct ec_response_get_protocol_info *)
> + proto_msg->data;
> + ec_dev->max_request = proto_info->max_request_packet_size -
> + sizeof(struct ec_host_request);
> + ec_dev->max_response = proto_info->max_response_packet_size -
> + sizeof(struct ec_host_response);
> + ec_dev->proto_version =
> + min(EC_HOST_REQUEST_VERSION,
> + fls(proto_info->protocol_versions) - 1);
> + dev_dbg(ec_dev->dev,
> + "using proto v%u\n",
> + ec_dev->proto_version);
> +
> + ec_dev->din_size = ec_dev->max_response +
> + sizeof(struct ec_host_response) +
> + EC_MAX_RESPONSE_OVERHEAD;
> + ec_dev->dout_size = ec_dev->max_request +
> + sizeof(struct ec_host_request) +
> + EC_MAX_REQUEST_OVERHEAD;
>
> /*
> - * Query the EC's status until it's no longer busy or
> - * we encounter an error.
> + * Check for PD
> */
> - for (i = 0; i < EC_COMMAND_RETRIES; i++) {
> - usleep_range(10000, 11000);
> + ret = cros_ec_host_command_proto_query(ec_dev, 1, proto_msg);
>
> - ret = ec_dev->cmd_xfer(ec_dev, status_msg);
> - if (ret < 0)
> - break;
> + if (ret) {
> + dev_dbg(ec_dev->dev, "no PD chip found: %d\n", ret);
> + ec_dev->max_passthru = 0;
> + } else {
> + dev_dbg(ec_dev->dev, "found PD chip\n");
> + ec_dev->max_passthru =
> + proto_info->max_request_packet_size -
> + sizeof(struct ec_host_request);
> + }
> + } else {
> + /* Try querying with a v2 hello message. */
> + ec_dev->proto_version = 2;
> + ret = cros_ec_host_command_proto_query_v2(ec_dev);
>
> - msg->result = status_msg->result;
> - if (status_msg->result != EC_RES_SUCCESS)
> - break;
> + if (ret == 0) {
> + /* V2 hello succeeded. */
> + dev_dbg(ec_dev->dev, "falling back to proto v2\n");
>
> - status = (struct ec_response_get_comms_status *)
> - status_msg->data;
> - if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
> - break;
> + ec_dev->max_request = EC_PROTO2_MAX_PARAM_SIZE;
> + ec_dev->max_response = EC_PROTO2_MAX_PARAM_SIZE;
> + ec_dev->max_passthru = 0;
> + ec_dev->pkt_xfer = NULL;
> + ec_dev->din_size = EC_MSG_BYTES;
> + ec_dev->dout_size = EC_MSG_BYTES;
> + } else {
> + /*
> + * It's possible for a test to occur too early when
> + * the EC isn't listening. If this happens, we'll
> + * test later when the first command is run.
> + */
> + ec_dev->proto_version = EC_PROTO_VERSION_UNKNOWN;
> + dev_dbg(ec_dev->dev, "EC query failed: %d\n", ret);
> + goto exit;
> }
> + }
>
> - kfree(status_msg);
> + devm_kfree(dev, ec_dev->din);
> + devm_kfree(dev, ec_dev->dout);
> +
> + ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
> + if (!ec_dev->din) {
> + ret = -ENOMEM;
> + goto exit;
> }
> +
> + ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
> + if (!ec_dev->dout) {
> + devm_kfree(dev, ec_dev->din);
> + ret = -ENOMEM;
> + goto exit;
> + }
> +
> exit:
> + kfree(proto_msg);
> + return ret;
> +}
> +EXPORT_SYMBOL(cros_ec_query_all);
> +
> +int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
> + struct cros_ec_command *msg)
> +{
> + int ret;
> +
> + mutex_lock(&ec_dev->lock);
> + if (ec_dev->proto_version == EC_PROTO_VERSION_UNKNOWN) {
> + ret = cros_ec_query_all(ec_dev);
> + if (ret) {
> + dev_err(ec_dev->dev,
> + "EC version unknown and query failed; aborting command\n");
> + mutex_unlock(&ec_dev->lock);
> + return ret;
> + }
> + }
> +
> + if (msg->insize > ec_dev->max_response) {
> + dev_dbg(ec_dev->dev, "clamping message receive buffer\n");
> + msg->insize = ec_dev->max_response;
> + }
> +
> + if (msg->command < EC_CMD_PASSTHRU_OFFSET(1)) {
> + if (msg->outsize > ec_dev->max_request) {
> + dev_err(ec_dev->dev,
> + "request of size %u is too big (max: %u)\n",
> + msg->outsize,
> + ec_dev->max_request);
> + mutex_unlock(&ec_dev->lock);
> + return -EMSGSIZE;
> + }
> + } else {
> + if (msg->outsize > ec_dev->max_passthru) {
> + dev_err(ec_dev->dev,
> + "passthru rq of size %u is too big (max: %u)\n",
> + msg->outsize,
> + ec_dev->max_passthru);
> + mutex_unlock(&ec_dev->lock);
> + return -EMSGSIZE;
> + }
> + }
> + ret = send_command(ec_dev, msg);
> mutex_unlock(&ec_dev->lock);
>
> return ret;
> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> index 7eee38abd02a..59d909434efd 100644
> --- a/include/linux/mfd/cros_ec.h
> +++ b/include/linux/mfd/cros_ec.h
> @@ -22,6 +22,15 @@
> #include <linux/mutex.h>
>
> /*
> + * Max bus-specific overhead incurred by request/responses.
> + * I2C requires 1 additional byte for requests.
> + * I2C requires 2 additional bytes for responses.
> + * */
> +#define EC_PROTO_VERSION_UNKNOWN 0
> +#define EC_MAX_REQUEST_OVERHEAD 1
> +#define EC_MAX_RESPONSE_OVERHEAD 2
> +
> +/*
> * Command interface between EC and AP, for LPC, I2C and SPI interfaces.
> */
> enum {
> @@ -88,6 +97,7 @@ struct cros_ec_command {
> * Returns the number of bytes received if the communication succeeded, but
> * that doesn't mean the EC was happy with the command. The caller
> * should check msg.result for the EC's result code.
> + * @pkt_xfer: send packet to EC and get response
> * @lock: one transaction at a time
> */
> struct cros_ec_device {
> @@ -104,15 +114,21 @@ struct cros_ec_device {
> unsigned int bytes, void *dest);
>
> /* These are used to implement the platform-specific interface */
> + u16 max_request;
> + u16 max_response;
> + u16 max_passthru;
> + u16 proto_version;
> void *priv;
> int irq;
> - uint8_t *din;
> - uint8_t *dout;
> + u8 *din;
> + u8 *dout;
> int din_size;
> int dout_size;
> bool wake_enabled;
> int (*cmd_xfer)(struct cros_ec_device *ec,
> struct cros_ec_command *msg);
> + int (*pkt_xfer)(struct cros_ec_device *ec,
> + struct cros_ec_command *msg);
> struct mutex lock;
> };
>
> @@ -194,4 +210,12 @@ int cros_ec_remove(struct cros_ec_device *ec_dev);
> */
> int cros_ec_register(struct cros_ec_device *ec_dev);
>
> +/**
> + * cros_ec_register - Query the protocol version supported by the ChromeOS EC
> + *
> + * @ec_dev: Device to register
> + * @return 0 if ok, -ve on error
> + */
> +int cros_ec_query_all(struct cros_ec_device *ec_dev);
> +
> #endif /* __LINUX_MFD_CROS_EC_H */

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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