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

[Icenowy Zheng]

01.03.2017, 01:56, "Maxime Ripard" <maxime.ripard at free-electrons.com>:
> On Mon, Feb 27, 2017 at 06:48:01PM +0800, Icenowy Zheng wrote:
>>  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.
>
> There's not a lot of endpoints indeed, but you need 28 vchans (2 *
> 14).

Sorry but I counted only 12 pairs of vchans:
Port 0. SRAM
Port 1. SDRAM
Port 6. UART0
Port 7. UART1
Port 8. UART2
Port 15. Audio Codec
Port 16. CE
Port 17. OTG EP1
Port 18. OTG EP2
Port 19. OTG EP3
Port 20. OTG EP4
Port 23. SPI0

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