Re: [RFC v2 5/5] Atmel MCI: Driver for Atmel on-chip MMC controllers

["Dan Williams" <dan.j.williams@intel.com>]

On Jan 29, 2008 11:10 AM, Haavard Skinnemoen <hskinnemoen@atmel.com> wrote:
[..]
> +/*
> + * Returns a mask of flags to be set in the command register when the
> + * command to start the transfer is to be sent.
> + */
> +static u32 atmci_prepare_data(struct mmc_host *mmc, struct mmc_data *data)
[..]
> +       for_each_sg(data->sg, sg, sg_len, i) {
> +               if (i == sg_len - 1)
> +                       dma_flags = DMA_PREP_INTERRUPT;
> +
> +               dev_vdbg(&mmc->class_dev, "  addr %08x len %u\n",
> +                               sg_dma_address(sg), sg_dma_len(sg));
> +
> +               desc = chan->device->device_prep_slave(chan,
> +                               sg_dma_address(sg), direction,
> +                               DMA_SLAVE_WIDTH_32BIT,
> +                               sg_dma_len(sg), dma_flags);
> +               desc->txd.callback = NULL;
> +               list_add_tail(&desc->client_node,
> +                               &host->dma.data_descs);
> +       }

Need to handle device_prep_slave returning NULL?