Re: [PATCH v2 4/5] mmc: davinci: don't use dma platform resources

From: Peter Ujfalusi
Date: Tue Mar 15 2016 - 04:57:35 EST


On 03/15/16 10:54, Peter Ujfalusi wrote:
> On 03/15/16 00:54, David Lechner wrote:
>> The davinci arch now has dma_slave_map tables for dma resources, so it is
>> no longer necessary to pass dma resources through the platform device.
>>
>> Signed-off-by: David Lechner <david@xxxxxxxxxxxxxx>
>> ---
>>
>> v2 changes: Remove platform_get_resource completly instead of just ignoring it.
>>
>>
>> drivers/mmc/host/davinci_mmc.c | 19 ++-----------------
>> 1 file changed, 2 insertions(+), 17 deletions(-)
>>
>> diff --git a/drivers/mmc/host/davinci_mmc.c b/drivers/mmc/host/davinci_mmc.c
>> index 8d10a92..dc96401 100644
>> --- a/drivers/mmc/host/davinci_mmc.c
>> +++ b/drivers/mmc/host/davinci_mmc.c
>> @@ -202,7 +202,6 @@ struct mmc_davinci_host {
>> u32 buffer_bytes_left;
>> u32 bytes_left;
>>
>> - u32 rxdma, txdma;
>> struct dma_chan *dma_tx;
>> struct dma_chan *dma_rx;
>> bool use_dma;
>> @@ -520,16 +519,14 @@ static int __init davinci_acquire_dma_channels(struct mmc_davinci_host *host)
>> dma_cap_set(DMA_SLAVE, mask);
>>
>> host->dma_tx =
>> - dma_request_slave_channel_compat(mask, edma_filter_fn,
>> - &host->txdma, mmc_dev(host->mmc), "tx");
>> + dma_request_slave_channel(mmc_dev(host->mmc), "tx");
>
> you would need to use dma_request_chan() to be able to rely on the legacy
> channel mapping.

In other words: w/o dma_request_chan() legacy boot will not work as you will
not get the DMA channel.

> I have staged commits for converting all daVinci and OMAP drivers, I'll attach
> the patch I have for davinci-mmc for reference.
> When we convert to use the dma_request_chan() we can handle deferred probing
> also...
>
>
>
>> if (!host->dma_tx) {
>> dev_err(mmc_dev(host->mmc), "Can't get dma_tx channel\n");
>> return -ENODEV;
>> }
>>
>> host->dma_rx =
>> - dma_request_slave_channel_compat(mask, edma_filter_fn,
>> - &host->rxdma, mmc_dev(host->mmc), "rx");
>> + dma_request_slave_channel(mmc_dev(host->mmc), "rx");
>> if (!host->dma_rx) {
>> dev_err(mmc_dev(host->mmc), "Can't get dma_rx channel\n");
>> r = -ENODEV;
>> @@ -1251,18 +1248,6 @@ static int __init davinci_mmcsd_probe(struct platform_device *pdev)
>> host = mmc_priv(mmc);
>> host->mmc = mmc; /* Important */
>>
>> - r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
>> - if (!r)
>> - dev_warn(&pdev->dev, "RX DMA resource not specified\n");
>> - else
>> - host->rxdma = r->start;
>> -
>> - r = platform_get_resource(pdev, IORESOURCE_DMA, 1);
>> - if (!r)
>> - dev_warn(&pdev->dev, "TX DMA resource not specified\n");
>> - else
>> - host->txdma = r->start;
>> -
>> host->mem_res = mem;
>> host->base = devm_ioremap(&pdev->dev, mem->start, mem_size);
>> if (!host->base)
>>
>
>


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