Re: [RESEND PATCH 7/8] mfd: cros_ec: add proto v3 skeleton

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You can merge change
https://chromium-review.googlesource.com/#/c/262870/ with it, that
fixes an issue with newer firmware.

Reviewed-by: Gwendal Grignou <gwendal@xxxxxxxxxxxx>
Tested-by: Gwendal Grignou <gwendal@xxxxxxxxxxxx>

On Mon, Apr 6, 2015 at 9:15 AM, Javier Martinez Canillas
<javier.martinez@xxxxxxxxxxxxxxx> wrote:
> From: Stephen Barber <smbarber@xxxxxxxxxxxx>
>
> 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@xxxxxxxxxxxx>
> Signed-off-by: Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx>
> ---
>  drivers/mfd/cros_ec.c                 | 363 +++++++++++++++++++++++++++++-----
>  drivers/mfd/cros_ec_i2c.c             |   4 +
>  drivers/mfd/cros_ec_spi.c             |   7 +-
>  drivers/platform/chrome/cros_ec_lpc.c |   4 +
>  include/linux/mfd/cros_ec.h           |  20 +-
>  5 files changed, 347 insertions(+), 51 deletions(-)
>
> diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
> index 70f6e55a096e..0972a7d36199 100644
> --- a/drivers/mfd/cros_ec.c
> +++ b/drivers/mfd/cros_ec.c
> @@ -30,11 +30,281 @@
>
>  static int dev_id;
>
> +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 = kzalloc(sizeof(*status_msg) + sizeof(*status),
> +                                    GFP_KERNEL);
> +               if (!status_msg)
> +                       return -ENOMEM;
> +
> +               status_msg->command = EC_CMD_GET_COMMS_STATUS;
> +               status_msg->insize = sizeof(*status);
> +
> +               /*
> +                * 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;
> +}
> +
> +static int cros_ec_host_command_proto_probe(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;
> +
> +       if (!ec_dev->pkt_xfer)
> +               return -EPROTONOSUPPORT;
> +
> +       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);
> +
> +       ret = send_command(ec_dev, msg);
> +
> +       if (ret < 0) {
> +               dev_dbg(ec_dev->dev,
> +                       "failed to probe 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_probe_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 = kzalloc(sizeof(*msg) + len, GFP_KERNEL);
> +       if (!msg)
> +               return -ENOMEM;
> +
> +       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;
> +}
> +
> +static int cros_ec_probe_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_probe(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;
> +
> +               /*
> +                * Check for PD
> +                */
> +               ret = cros_ec_host_command_proto_probe(ec_dev, 1, proto_msg);
> +
> +               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 probing with a v2 hello message. */
> +               ec_dev->proto_version = 2;
> +               ret = cros_ec_host_command_proto_probe_v2(ec_dev);
> +
> +               if (ret == 0) {
> +                       /* V2 hello succeeded. */
> +                       dev_dbg(ec_dev->dev, "falling back to proto v2\n");
> +
> +                       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 probe to occur too early when
> +                        * the EC isn't listening. If this happens, we'll
> +                        * probe later when the first command is run.
> +                        */
> +                       ec_dev->proto_version = EC_PROTO_VERSION_UNKNOWN;
> +                       dev_dbg(ec_dev->dev, "EC probe failed: %d\n", ret);
> +                       goto exit;
> +               }
> +       }
> +
> +       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;
> +}
> +
>  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;
> @@ -44,7 +314,7 @@ 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;
>  }
> @@ -74,46 +344,43 @@ int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
>         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;
>
> -               status_msg = kzalloc(sizeof(*status_msg) + sizeof(*status),
> -                                    GFP_KERNEL);
> -               if (!status_msg) {
> -                       ret = -ENOMEM;
> -                       goto exit;
> +       if (ec_dev->proto_version == EC_PROTO_VERSION_UNKNOWN) {
> +               ret = cros_ec_probe_all(ec_dev);
> +               if (ret) {
> +                       dev_err(ec_dev->dev,
> +                               "EC version unknown and probe failed; aborting command\n");
> +                       mutex_unlock(&ec_dev->lock);
> +                       return ret;
>                 }
> +       }
>
> -               status_msg->command = EC_CMD_GET_COMMS_STATUS;
> -               status_msg->insize = sizeof(*status);
> -
> -               /*
> -                * 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;
> +       if (msg->insize > ec_dev->max_response) {
> +               dev_dbg(ec_dev->dev, "clamping message receive buffer\n");
> +               msg->insize = ec_dev->max_response;
> +       }
>
> -                       status = (struct ec_response_get_comms_status *)
> -                                status_msg->data;
> -                       if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
> -                               break;
> +       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;
>                 }
> -
> -               kfree(status_msg);
>         }
> -exit:
> +
> +       ret = send_command(ec_dev, msg);
>         mutex_unlock(&ec_dev->lock);
>
>         return ret;
> @@ -132,21 +399,23 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
>         struct device *dev = ec_dev->dev;
>         int err = 0;
>
> +       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->id = dev_id;
>
> -       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->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_probe_all(ec_dev);
> +
>         err = mfd_add_devices(dev, ec_dev->id, 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 32b1df29fc58..d56dfb9dd463 100644
> --- a/drivers/platform/chrome/cros_ec_lpc.c
> +++ b/drivers/platform/chrome/cros_ec_lpc.c
> @@ -205,7 +205,11 @@ 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/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> index 2bee6ac74ffb..f27ce4b7736b 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 {
> @@ -89,6 +98,7 @@ 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 {
> @@ -105,16 +115,22 @@ 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;
>         int id;
> -       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;
>  };
>
> --
> 2.1.4
>
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