Messages in this thread | | | Date | Sat, 19 Mar 2022 07:24:58 +0100 | Subject | Re: [PATCH v2] dmaengine: qcom_hidma: Remove useless DMA-32 fallback configuration | From | Christophe JAILLET <> |
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Le 22/01/2022 à 19:05, Sinan Kaya a écrit : > On 1/15/2022 2:35 AM, Christophe JAILLET wrote: >> As stated in [1], dma_set_mask() with a 64-bit mask never fails if >> dev->dma_mask is non-NULL. >> So, if it fails, the 32 bits case will also fail for the same reason. >> >> Simplify code and remove some dead code accordingly. >> >> [1]: >> https://lore.kernel.org/linux-kernel/YL3vSPK5DXTNvgdx@infradead.org/#t >> > > Can we please document this?
Hi, the patch has been applied, but [1] is sometimes given as an explanation link.
CJ
[1]: https://lists.linuxfoundation.org/pipermail/iommu/2019-February/033674.html
> > Usual practice was to try allocating 64 bit DMA if possible and fallback > to 32 bits. > >> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> >> --- >> v2: have the subject and updated driver match >> --- >> drivers/dma/qcom/hidma.c | 4 +--- >> 1 file changed, 1 insertion(+), 3 deletions(-) >> >> diff --git a/drivers/dma/qcom/hidma.c b/drivers/dma/qcom/hidma.c >> index 65d054bb11aa..51587cf8196b 100644 >> --- a/drivers/dma/qcom/hidma.c >> +++ b/drivers/dma/qcom/hidma.c >> @@ -838,9 +838,7 @@ static int hidma_probe(struct platform_device *pdev) >> rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64)); >> if (rc) { >> dev_warn(&pdev->dev, "unable to set coherent mask to 64"); >> - rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32)); >> - if (rc) >> - goto dmafree; >> + goto dmafree; >> } >> dmadev->lldev = hidma_ll_init(dmadev->ddev.dev, > >
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