[alsa-devel] [PATCH 5/9] dmaengine: sun6i: support V3s SoC variant

[Icenowy Zheng]

27.02.2017, 15:50, "Maxime Ripard" <maxime.ripard at free-electrons.com>:
> On Sat, Feb 25, 2017 at 08:30:25PM +0800, Icenowy Zheng wrote:
>>  Allwinner V3s has a DMA engine similar to the ones from A31, but with
>>  fewer channels and DRQs.
>>
>>  Add support for it.
>>
>>  As it also needs the special gate bit, make the gate bit generic.
>
> That should be part of a separate patch.

OK.

>
>>  According to BSP source code, SUN8IW6 (A83T) also needs the bit, so it
>>  have also been specified gate_needed property.
>>
>>  Signed-off-by: Icenowy Zheng <icenowy at aosc.xyz>
>>  ---
>>   Documentation/devicetree/bindings/dma/sun6i-dma.txt | 1 +
>>   drivers/dma/sun6i-dma.c | 17 ++++++++++++++---
>>   2 files changed, 15 insertions(+), 3 deletions(-)
>>
>>  diff --git a/Documentation/devicetree/bindings/dma/sun6i-dma.txt b/Documentation/devicetree/bindings/dma/sun6i-dma.txt
>>  index 6b267045f522..98fbe1a5c6dd 100644
>>  --- a/Documentation/devicetree/bindings/dma/sun6i-dma.txt
>>  +++ b/Documentation/devicetree/bindings/dma/sun6i-dma.txt
>>  @@ -9,6 +9,7 @@ Required properties:
>>                     "allwinner,sun8i-a23-dma"
>>                     "allwinner,sun8i-a83t-dma"
>>                     "allwinner,sun8i-h3-dma"
>>  + "allwinner,sun8i-v3s-dma"
>>   - reg: Should contain the registers base address and length
>>   - interrupts: Should contain a reference to the interrupt used by this device
>>   - clocks: Should contain a reference to the parent AHB clock
>>  diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
>>  index a2358780ab2c..1f38424c1b14 100644
>>  --- a/drivers/dma/sun6i-dma.c
>>  +++ b/drivers/dma/sun6i-dma.c
>>  @@ -101,6 +101,7 @@ struct sun6i_dma_config {
>>           u32 nr_max_channels;
>>           u32 nr_max_requests;
>>           u32 nr_max_vchans;
>>  + bool gate_needed;
>>   };
>>
>>   /*
>>  @@ -1009,12 +1010,14 @@ 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 = {
>>           .nr_max_channels = 8,
>>           .nr_max_requests = 28,
>>           .nr_max_vchans = 39,
>>  + .gate_needed = true,
>>   };
>>
>>   /*
>>  @@ -1028,11 +1031,19 @@ static struct sun6i_dma_config sun8i_h3_dma_cfg = {
>>           .nr_max_vchans = 34,
>>   };
>>
>>  +static struct sun6i_dma_config sun8i_v3s_dma_cfg = {
>>  + .nr_max_channels = 8,
>>  + .nr_max_requests = 23,
>>  + .nr_max_vchans = 24,
>
> This one is suspicious. There's just a single endpoint that can be
> used in both directions?

nr_max_vchans is the endpoint number. nr_max_requests is the
maximum DRQ number, for V3s, according to the datasheet, it's
23: SPI0_{R,T}X.

>
> Maxime
>
> --
> Maxime Ripard, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com