Hi Balbi,
If CONFIG_DMA_CMA=y, dma mask is set properly. The issue just happen
when CONFIG_DMA_CMA is not set. In this case, dma mask is not set and
we need this code to check if dma mask should be manually set to 32 or
64.
----
Thang
On Wed, Mar 30, 2016 at 8:09 PM, Felipe Balbi
<felipe.balbi@xxxxxxxxxxxxxxx> wrote:
>
> Hi,
>
> "Thang Q. Nguyen" <tqnguyen@xxxxxxx> writes:
>> From: "Thang Q. Nguyen" <tqnguyen@xxxxxxx>
>>
>> Add 64-bit DMA operation support to the USB DWC3 driver.
>> First attempt to set the coherent DMA mask for 64-bit DMA.
>> If that failed, attempt again with 32-bit DMA.
>>
>> Changes from v2:
>> - None.
>>
>> Changes from v1:
>> - Remove WARN_ON if dma_mask is NULL
>
> these changes lines should be between the tearline (---) and diffstat
> below.
>
>> Signed-off-by: Thang Q. Nguyen <tqnguyen@xxxxxxx>
>> ---
>> drivers/usb/dwc3/core.c | 15 +++++++++++++++
>> 1 file changed, 15 insertions(+)
>>
>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>> index de5e01f..2479c24 100644
>> --- a/drivers/usb/dwc3/core.c
>> +++ b/drivers/usb/dwc3/core.c
>> @@ -831,6 +831,21 @@ static int dwc3_probe(struct platform_device *pdev)
>> dwc->mem = mem;
>> dwc->dev = dev;
>>
>> + /* Try to set 64-bit DMA first */
>> + if (!pdev->dev.dma_mask)
>> + /* Platform did not initialize dma_mask */
>> + ret = dma_coerce_mask_and_coherent(&pdev->dev,
>> + DMA_BIT_MASK(64));
>> + else
>> + ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
>> +
>> + /* If seting 64-bit DMA mask fails, fall back to 32-bit DMA mask */
>> + if (ret) {
>> + ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
>> + if (ret)
>> + return ret;
>> + }
>
> Also, why is it so that you need this now ? glue layers are copying dma
> mask from parent device and that should be set properly. This really
> shouldn't be necessary in dwc3-core; it would mean that glue layer
> didn't set this device up properly.
>
> --
> balbi
--
Thang Q. Nguyen | Staff SW Eng.
C: +849.7684.7606 | O: +848.3770.0640
F: +848.3770.0641 | tqnguyen@xxxxxxx
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