From: Amelie Delaunay <amelie.delaunay@foss.st.com>
To: Marek Vasut <marex@denx.de>, Jonathan Corbet <corbet@lwn.net>,
Vinod Koul <vkoul@kernel.org>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: <linux-doc@vger.kernel.org>, <dmaengine@vger.kernel.org>,
<linux-stm32@st-md-mailman.stormreply.com>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 3/4] dmaengine: stm32-dma: add support to trigger STM32 MDMA
Date: Tue, 19 Jul 2022 17:30:49 +0200 [thread overview]
Message-ID: <d46e5eee-c8ae-545f-e69e-1dd2f2e71323@foss.st.com> (raw)
In-Reply-To: <e1fbf7cf-1bb7-6583-3713-7dbd58a4898e@denx.de>
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
next prev parent reply other threads:[~2022-07-19 15:31 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-13 14:21 [PATCH v2 0/4] STM32 DMA-MDMA chaining feature Amelie Delaunay
2022-07-13 14:21 ` [PATCH v2 1/4] docs: arm: stm32: introduce " Amelie Delaunay
2022-07-13 14:21 ` [PATCH v2 2/4] dmaengine: stm32-dmamux: set dmamux channel id in dma features bitfield Amelie Delaunay
2022-07-13 14:21 ` [PATCH v2 3/4] dmaengine: stm32-dma: add support to trigger STM32 MDMA Amelie Delaunay
2022-07-14 19:02 ` Marek Vasut
2022-07-19 15:30 ` Amelie Delaunay [this message]
2022-07-15 18:01 ` kernel test robot
2022-07-13 14:21 ` [PATCH v2 4/4] dmaengine: stm32-mdma: add support to be triggered by STM32 DMA Amelie Delaunay
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