于 2017年6月14日 GMT+08:00 下午4:45:29, Vinod Koul <vinod.koul@xxxxxxxxx> 写到:
>On Wed, Jun 14, 2017 at 04:32:57PM +0800, Icenowy Zheng wrote:
>>
>>
>> 于 2017年6月14日 GMT+08:00 下午4:32:52, Vinod Koul <vinod.koul@xxxxxxxxx>
>写到:
>> >On Mon, Jun 05, 2017 at 08:33:47PM +0800, Icenowy Zheng wrote:
>> >> From: Icenowy Zheng <icenowy@xxxxxxxx>
>> >>
>> >> Originally we enable a special gate bit when the compatible
>indicates
>> >> A23/33.
>> >>
>> >> But according to BSP sources and user manuals, more SoCs will need
>> >this
>> >> gate bit.
>> >>
>> >> So make it a common quirk configured in the config struct.
>> >>
>> >> Signed-off-by: Icenowy Zheng <icenowy@xxxxxxxx>
>> >> ---
>> >> Changes since original codec patchset v3:
>> >> - Refactored comments to cover some words found in official
>> >documents.
>> >> - Removed the comments when toggling the gate bit.
>> >>
>> >> drivers/dma/sun6i-dma.c | 20 +++++++++++++-------
>> >> 1 file changed, 13 insertions(+), 7 deletions(-)
>> >>
>> >> diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
>> >> index a2358780ab2c..252b59c1d1d5 100644
>> >> --- a/drivers/dma/sun6i-dma.c
>> >> +++ b/drivers/dma/sun6i-dma.c
>> >> @@ -101,6 +101,17 @@ struct sun6i_dma_config {
>> >> u32 nr_max_channels;
>> >> u32 nr_max_requests;
>> >> u32 nr_max_vchans;
>> >> + /*
>> >> + * In the datasheets/user manuals of newer Allwinner SoCs, a
>> >special
>> >> + * bit (bit 2 at register 0x20) is present.
>> >> + * It's named "DMA MCLK interface circuit auto gating bit" in
>the
>> >> + * documents, and the footnote of this register says that this
>bit
>> >> + * should be set up when initializing the DMA controller.
>> >> + * Allwinner A23/A33 user manuals do not have this bit
>documented,
>> >> + * however these SoCs really have and need this bit, as seen in
>the
>> >> + * BSP kernel source code.
>> >> + */
>> >> + bool gate_needed;
>> >
>> >Since this is a hw property, why is this not added as an optional DT
>> >property?
>>
>> As it's SoC-specified.
>>
>> Some SoCs need it, and some don't.
>
>and that is the reason it should be a property
>
>>
>> SoC info is in compatible, so there's no reason to make it a
>property.
>
>that's why it would need to be optional for the SoC's that needs
>these..
I don't think it proper to add block-specified properties
that can be bound to compatible.
I added Rob Herring to the recipient list.
Rob, do you think this can be added as a property?
This is SoC-specific and compatibles are also SoC-specific.
>
>>
>> >
>> >> };
>> >>
>> >> /*
>> >> @@ -1009,6 +1020,7 @@ static struct sun6i_dma_config
>> >sun8i_a23_dma_cfg = {
>> >> .nr_max_channels = 8,
>> >> .nr_max_requests = 24,
>> >> .nr_max_vchans = 37,
>> >> + .gate_needed = true,
>> >> };
>> >>
>> >> static struct sun6i_dma_config sun8i_a83t_dma_cfg = {
>> >> @@ -1174,13 +1186,7 @@ static int sun6i_dma_probe(struct
>> >platform_device *pdev)
>> >> goto err_dma_unregister;
>> >> }
>> >>
>> >> - /*
>> >> - * sun8i variant requires us to toggle a dma gating register,
>> >> - * as seen in Allwinner's SDK. This register is not documented
>> >> - * in the A23 user manual.
>> >> - */
>> >> - if (of_device_is_compatible(pdev->dev.of_node,
>> >> - "allwinner,sun8i-a23-dma"))
>> >> + if (sdc->cfg->gate_needed)
>> >> writel(SUN8I_DMA_GATE_ENABLE, sdc->base + SUN8I_DMA_GATE);
>> >>
>> >> return 0;
>> >> --
>> >> 2.12.2
>> >>
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