[U-Boot] [PATCH V3 1/6] misc: add "call" uclass op

[Simon Glass]

Hi Stephen,

On 5 August 2016 at 11:03, Stephen Warren <swarren at wwwdotorg.org> wrote:
> From: Stephen Warren <swarren at nvidia.com>
>
> The call op requests that the callee pass a message to the underlying HW
> or device, wait for a response, and then pass back the response error code
> and message to the callee. It is useful for drivers that represent some
> kind of messaging or IPC channel to a remote device.
>
> Signed-off-by: Stephen Warren <swarren at nvidia.com>
> ---
> v3: New patch.
> ---
>  drivers/misc/misc-uclass.c | 11 +++++++++++
>  include/misc.h             | 35 +++++++++++++++++++++++++++++++++++
>  2 files changed, 46 insertions(+)

Acked-by: Simon Glass <sjg at chromium.org>

One suggestion below.

>
> diff --git a/drivers/misc/misc-uclass.c b/drivers/misc/misc-uclass.c
> index 13a6ea508b14..d9eea3dac5c0 100644
> --- a/drivers/misc/misc-uclass.c
> +++ b/drivers/misc/misc-uclass.c
> @@ -45,6 +45,17 @@ int misc_ioctl(struct udevice *dev, unsigned long request, void *buf)
>         return ops->ioctl(dev, request, buf);
>  }
>
> +int misc_call(struct udevice *dev, int msgid, void *tx_msg, int tx_size,
> +             void *rx_msg, int rx_size)
> +{
> +       const struct misc_ops *ops = device_get_ops(dev);
> +
> +       if (!ops->call)
> +               return -ENOSYS;
> +
> +       return ops->call(dev, msgid, tx_msg, tx_size, rx_msg, rx_size);
> +}
> +
>  UCLASS_DRIVER(misc) = {
>         .id             = UCLASS_MISC,
>         .name           = "misc",
> diff --git a/include/misc.h b/include/misc.h
> index 2b788143b54c..ba417380416a 100644
> --- a/include/misc.h
> +++ b/include/misc.h
> @@ -38,6 +38,27 @@ int misc_write(struct udevice *dev, int offset, void *buf, int size);
>  int misc_ioctl(struct udevice *dev, unsigned long request, void *buf);
>
>  /*
> + * Send a message to the device and wait for a response.
> + *
> + * The caller provides the message type/ID and payload to be sent.
> + * The callee constructs any message header required, transmits it to the
> + * target, waits for a response, checks any error code in the response,
> + * strips any message header from the response, and returns the error code
> + * (or a parsed version of it) and the response message payload.
> + *
> + * @dev: the device.
> + * @msgid: the message ID/number to send.
> + * tx_msg: the request/transmit message payload.
> + * tx_size: the size of the buffer pointed at by tx_msg.
> + * rx_msg: the buffer to receive the response message payload. May be NULL if
> + *         the caller only cares about the error code.
> + * rx_size: the size of the buffer pointed at by rx_msg.
> + * @return 0 if OK, -ve on error

How about returning the number of bytes received? It might be that
rx_size is the receive buffer size, but fewer bytes are returned.

> + */
> +int misc_call(struct udevice *dev, int msgid, void *tx_msg, int tx_size,
> +             void *rx_msg, int rx_size);
> +
> +/*
>   * struct misc_ops - Driver model Misc operations
>   *
>   * The uclass interface is implemented by all miscellaneous devices which
> @@ -74,6 +95,20 @@ struct misc_ops {
>          * @return: 0 if OK, -ve on error
>          */
>         int (*ioctl)(struct udevice *dev, unsigned long request, void *buf);
> +       /*
> +        * Send a message to the device and wait for a response.
> +        *
> +        * @dev: the device
> +        * @msgid: the message ID/number to send
> +        * tx_msg: the request/transmit message payload
> +        * tx_size: the size of the buffer pointed at by tx_msg
> +        * rx_msg: the buffer to receive the response message payload. May be
> +        *         NULL if the caller only cares about the error code.
> +        * rx_size: the size of the buffer pointed at by rx_msg
> +        * @return 0 if OK, -ve on error
> +        */
> +       int (*call)(struct udevice *dev, int msgid, void *tx_msg, int tx_size,
> +                   void *rx_msg, int rx_size);
>  };
>
>  #endif /* _MISC_H_ */
> --
> 2.9.2
>

Regards,
Simon