Messages in this thread Patch in this message | | | Date | Tue, 19 Jul 2022 17:30:49 +0200 | Subject | Re: [PATCH v2 3/4] dmaengine: stm32-dma: add support to trigger STM32 MDMA | From | Amelie Delaunay <> |
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Hi Marek,
Thanks for reviewing.
On 7/14/22 21:02, Marek Vasut wrote: > On 7/13/22 16:21, Amelie Delaunay wrote: > > [...] > >> diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c >> index adb25a11c70f..3916295fe154 100644 >> --- a/drivers/dma/stm32-dma.c >> +++ b/drivers/dma/stm32-dma.c >> @@ -142,6 +142,8 @@ >> #define STM32_DMA_DIRECT_MODE_GET(n) (((n) & >> STM32_DMA_DIRECT_MODE_MASK) >> 2) >> #define STM32_DMA_ALT_ACK_MODE_MASK BIT(4) >> #define STM32_DMA_ALT_ACK_MODE_GET(n) (((n) & >> STM32_DMA_ALT_ACK_MODE_MASK) >> 4) >> +#define STM32_DMA_MDMA_STREAM_ID_MASK GENMASK(19, 16) >> +#define STM32_DMA_MDMA_STREAM_ID_GET(n) (((n) & >> STM32_DMA_MDMA_STREAM_ID_MASK) >> 16) > > Try FIELD_GET() from include/linux/bitfield.h > > [...] >
Yes, but not only on this new line. I'll add a prior patch to the patchset to use FIELD_{GET,PREP}() helpers every where custom macros are used.
>> @@ -1630,6 +1670,20 @@ static int stm32_dma_probe(struct >> platform_device *pdev) >> chan->id = i; >> chan->vchan.desc_free = stm32_dma_desc_free; >> vchan_init(&chan->vchan, dd); >> + >> + chan->mdma_config.ifcr = res->start; >> + chan->mdma_config.ifcr += (chan->id & 4) ? STM32_DMA_HIFCR : >> STM32_DMA_LIFCR; >> + >> + chan->mdma_config.tcf = STM32_DMA_TCI; >> + /* >> + * bit0 of chan->id represents the need to left shift by 6 >> + * bit1 of chan->id represents the need to extra left shift >> by 16 >> + * TCIF0, chan->id = b0000; TCIF4, chan->id = b0100: left >> shift by 0*6 + 0*16 >> + * TCIF1, chan->id = b0001; TCIF5, chan->id = b0101: left >> shift by 1*6 + 0*16 >> + * TCIF2, chan->id = b0010; TCIF6, chan->id = b0110: left >> shift by 0*6 + 1*16 >> + * TCIF3, chan->id = b0011; TCIF7, chan->id = b0111: left >> shift by 1*6 + 1*16 >> + */ >> + chan->mdma_config.tcf <<= (6 * (chan->id & 0x1) + 16 * >> ((chan->id & 0x2) >> 1)); > > Some sort of symbolic macros instead of open-coded constants could help > readability here. >
I agree. As the same kind of computation is done in stm32_dma_irq_status() and stm32_dma_irq_clear(), I'll add another prior patch to the patchset to introduce new macro helpers to get ISR/IFCR offset depending on channel id, and to get channel flags mask depending on channel id.
> [...]
Regards, Amelie
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