Re: [PATCH] mmc: sh_mmcif: rework dma channel handling

[Ulf Hansson]

On 16 November 2015 at 17:08, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> When compiling the sh_mmcif driver for ARM64, we currently
> get a harmless build warning:
>
> ../drivers/mmc/host/sh_mmcif.c: In function 'sh_mmcif_request_dma_one':
> ../drivers/mmc/host/sh_mmcif.c:417:4: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
>     (void *)pdata->slave_id_tx :
>     ^
> ../drivers/mmc/host/sh_mmcif.c:418:4: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
>     (void *)pdata->slave_id_rx;
>
> This could be worked around by adding another cast to uintptr_t, but
> I decided to simplify the code a little more to avoid that. This
> splits out the platform data using code into a separate function
> and builds that only for CONFIG_SUPERH. This part still has a typecast
> but does not need a second one. The SH platform code could be further
> modified to pass a pointer directly as we do on other architectures
> when we have a filter function.
>
> The normal case is simplified further and now just calls
> dma_request_slave_channel() directly without going through the
> compat handling.
>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

Thanks, applied for next!

FYI: There were some check patch warnings, I decided to fix them
myself before applying.

Kind regards
Uffe

> ---
>  drivers/mmc/host/sh_mmcif.c | 80 +++++++++++++++++---------------------------------
>  1 file changed, 34 insertions(+), 46 deletions(-)
>
>
> diff --git a/drivers/mmc/host/sh_mmcif.c b/drivers/mmc/host/sh_mmcif.c
> index ad9ffea7d659..d964c99f3a30 100644
> --- a/drivers/mmc/host/sh_mmcif.c
> +++ b/drivers/mmc/host/sh_mmcif.c
> @@ -397,38 +397,26 @@ static void sh_mmcif_start_dma_tx(struct sh_mmcif_host *host)
>  }
>
>  static struct dma_chan *
> -sh_mmcif_request_dma_one(struct sh_mmcif_host *host,
> -                        struct sh_mmcif_plat_data *pdata,
> -                        enum dma_transfer_direction direction)
> +sh_mmcif_request_dma_pdata(struct sh_mmcif_host *host, uintptr_t slave_id)
>  {
> -       struct dma_slave_config cfg = { 0, };
> -       struct dma_chan *chan;
> -       void *slave_data = NULL;
> -       struct resource *res;
> -       struct device *dev = sh_mmcif_host_to_dev(host);
>         dma_cap_mask_t mask;
> -       int ret;
>
>         dma_cap_zero(mask);
>         dma_cap_set(DMA_SLAVE, mask);
> +       if (slave_id <= 0)
> +               return NULL;
>
> -       if (pdata)
> -               slave_data = direction == DMA_MEM_TO_DEV ?
> -                       (void *)pdata->slave_id_tx :
> -                       (void *)pdata->slave_id_rx;
> -
> -       chan = dma_request_slave_channel_compat(mask, shdma_chan_filter,
> -                               slave_data, dev,
> -                               direction == DMA_MEM_TO_DEV ? "tx" : "rx");
> -
> -       dev_dbg(dev, "%s: %s: got channel %p\n", __func__,
> -               direction == DMA_MEM_TO_DEV ? "TX" : "RX", chan);
> +       return dma_request_channel(mask, shdma_chan_filter, (void *)slave_id);
> +}
>
> -       if (!chan)
> -               return NULL;
> +static int sh_mmcif_dma_slave_config(struct sh_mmcif_host *host,
> +                                    struct dma_chan *chan,
> +                                    enum dma_transfer_direction direction)
> +{
> +       struct resource *res;
> +       struct dma_slave_config cfg = { 0, };
>
>         res = platform_get_resource(host->pd, IORESOURCE_MEM, 0);
> -
>         cfg.direction = direction;
>
>         if (direction == DMA_DEV_TO_MEM) {
> @@ -439,38 +427,38 @@ sh_mmcif_request_dma_one(struct sh_mmcif_host *host,
>                 cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
>         }
>
> -       ret = dmaengine_slave_config(chan, &cfg);
> -       if (ret < 0) {
> -               dma_release_channel(chan);
> -               return NULL;
> -       }
> -
> -       return chan;
> +       return dmaengine_slave_config(chan, &cfg);
>  }
>
> -static void sh_mmcif_request_dma(struct sh_mmcif_host *host,
> -                                struct sh_mmcif_plat_data *pdata)
> +static void sh_mmcif_request_dma(struct sh_mmcif_host *host)
>  {
>         struct device *dev = sh_mmcif_host_to_dev(host);
>         host->dma_active = false;
>
> -       if (pdata) {
> -               if (pdata->slave_id_tx <= 0 || pdata->slave_id_rx <= 0)
> -                       return;
> -       } else if (!dev->of_node) {
> -               return;
> +       /* We can only either use DMA for both Tx and Rx or not use it at all */
> +       if (IS_ENABLED(CONFIG_SUPERH) && dev->platform_data) {
> +               struct sh_mmcif_plat_data *pdata = dev->platform_data;
> +               host->chan_tx = sh_mmcif_request_dma_pdata(host, pdata->slave_id_tx);
> +               host->chan_rx = sh_mmcif_request_dma_pdata(host, pdata->slave_id_rx);
> +       } else {
> +               host->chan_tx = dma_request_slave_channel(dev, "tx");
> +               host->chan_tx = dma_request_slave_channel(dev, "rx");
>         }
> +       dev_dbg(dev, "%s: got channel TX %p RX %p\n", __func__, host->chan_tx, host->chan_rx);
>
> -       /* We can only either use DMA for both Tx and Rx or not use it at all */
> -       host->chan_tx = sh_mmcif_request_dma_one(host, pdata, DMA_MEM_TO_DEV);
> -       if (!host->chan_tx)
> -               return;
> +       if (!host->chan_tx || !host->chan_rx ||
> +           sh_mmcif_dma_slave_config(host, host->chan_tx, DMA_MEM_TO_DEV) ||
> +           sh_mmcif_dma_slave_config(host, host->chan_rx, DMA_DEV_TO_MEM))
> +               goto error;
>
> -       host->chan_rx = sh_mmcif_request_dma_one(host, pdata, DMA_DEV_TO_MEM);
> -       if (!host->chan_rx) {
> +       return;
> +
> +error:
> +       if (host->chan_tx)
>                 dma_release_channel(host->chan_tx);
> -               host->chan_tx = NULL;
> -       }
> +       if (host->chan_rx)
> +               dma_release_channel(host->chan_rx);
> +       host->chan_tx = host->chan_rx = NULL;
>  }
>
>  static void sh_mmcif_release_dma(struct sh_mmcif_host *host)
> @@ -1102,7 +1090,7 @@ static void sh_mmcif_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>         if (ios->power_mode == MMC_POWER_UP) {
>                 if (!host->card_present) {
>                         /* See if we also get DMA */
> -                       sh_mmcif_request_dma(host, dev->platform_data);
> +                       sh_mmcif_request_dma(host);
>                         host->card_present = true;
>                 }
>                 sh_mmcif_set_power(host, ios);
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/