On 7/27/24 8:15 AM, Jonathan Cameron wrote:
> On Mon, 22 Jul 2024 16:57:09 -0500
> David Lechner <dlechner@xxxxxxxxxxxx> wrote:
>
>> +/**
>> + * spi_offload_prepare - prepare offload hardware for a transfer
>> + * @spi: The spi device to use for the transfers.
>> + * @id: Function ID if SPI device uses more than one offload or NULL.
>> + * @msg: The SPI message to use for the offload operation.
>> + *
>> + * Requests an offload instance with the specified ID and programs it with the
>> + * provided message.
>> + *
>> + * The message must not be pre-optimized (do not call spi_optimize_message() on
>> + * the message).
>> + *
>> + * Calls must be balanced with spi_offload_unprepare().
>> + *
>> + * Return: 0 on success, else a negative error code.
>> + */
>> +int spi_offload_prepare(struct spi_device *spi, const char *id,
>> + struct spi_message *msg)
>> +{
>> + struct spi_controller *ctlr = spi->controller;
>> + int ret;
>> +
>> + if (!ctlr->offload_ops)
>> + return -EOPNOTSUPP;
>> +
>> + msg->offload = true;
> I'd set this later perhaps as...
If we move it, then we would have to create a new function
to call instead of spi_optimize_message() so that the controller
driver can know that this is an offload message and not a
regular message since they will need to be handled differently
during the optimization phase.
>> +
>> + ret = spi_optimize_message(spi, msg);
>> + if (ret)
>
> It otherwise needs clearing here so it doesn't have side
> effects if an error occurs.
>
>> + return ret;
>> +
>> + mutex_lock(&ctlr->io_mutex);
>> + ret = ctlr->offload_ops->prepare(spi, id, msg);
>> + mutex_unlock(&ctlr->io_mutex);
>> +
>> + if (ret) {
>> + spi_unoptimize_message(msg);
>> + msg->offload = false;
>> + return ret;
>> + }
>> +
>> + return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(spi_offload_prepare);
>
