Re: [PATCH 01/10] dmaengine: sun6i: Correct setting of clock autogating register for A83T/H3

André Przywara
2017-09-03T23:26:51Z

On 03/09/17 23:40, Stefan Brüns wrote:
> The H83T uses a compatible string different from the A23, but requires

A83T

> the same clock autogating register setting.
>
> The H3 also requires setting the clock autogating register, but has
> the register at a different offset.
>
> Some currently available SoCs not yet supported by the sun6i-dma driver
> will require new compatible strings. These SoCs either follow the A23
> register model (e.g. V3s) or the H3 register model (A64, R40), so a new
> variable is added to the config struct to group SoCs with common register
> models.

As mentioned in that other mail, using the actual properties as names
here instead of grouping them to rather arbitrary groups seems more
useful and future-proof to me and should be easier to read.
In this case this should simplify this patch:
sun8i_a23_dma_cfg = {
.nr_max_channels = 8,
.nr_max_requests = 24,
.nr_max_vchans = 37,
+ .auto_clock_gate = 0x20,
...
- if (of_device_is_compatible(pdev->dev.of_node,
- "allwinner,sun8i-a23-dma"))
- writel(SUN8I_DMA_GATE_ENABLE, sdc->base + SUN8I_DMA_GATE);
+ if (sdc->cfg->auto_clock_gate)
+ writel(SUN8I_DMA_GATE_ENABLE,
+ sdc->base + sdc->cfg->auto_clock_gate);

> Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
> ---
> drivers/dma/sun6i-dma.c | 34 +++++++++++++++++++++++++++++++---
> 1 file changed, 31 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
> index a2358780ab2c..1d9b3be30d22 100644
> --- a/drivers/dma/sun6i-dma.c
> +++ b/drivers/dma/sun6i-dma.c
> @@ -48,6 +48,9 @@
> #define SUN8I_DMA_GATE 0x20
> #define SUN8I_DMA_GATE_ENABLE 0x4
>
> +#define SUNXI_H3_SECURITE_REG 0x20

typo? SUNXI_H3_SECURITY_REG ?

Cheers,
Andre.

> +#define SUNXI_H3_DMA_GATE 0x28
> +#define SUNXI_H3_DMA_GATE_ENABLE 0x4
> /*
> * Channels specific registers
> */
> @@ -90,6 +93,21 @@
> #define NORMAL_WAIT 8
> #define DRQ_SDRAM 1
>
> +/*
> + * DMA Controller generations
> + *
> + * Newer SoC generations changed or added some register definitions:
> + * - A23 added a clock gate register
> + * - H3 has a different offset for the clock gating register,
> + * the burst length field has a different offset in the channel
> + * configuration register, also additional burst lengths/widths.
> + */
> +enum dmac_variant {
> + DMAC_VARIANT_A31,
> + DMAC_VARIANT_A23,
> + DMAC_VARIANT_H3,
> +};
> +
> /*
> * Hardware channels / ports representation
> *
> @@ -101,6 +119,7 @@ struct sun6i_dma_config {
> u32 nr_max_channels;
> u32 nr_max_requests;
> u32 nr_max_vchans;
> + enum dmac_variant dmac_variant;
> };
>
> /*
> @@ -998,6 +1017,7 @@ static struct sun6i_dma_config sun6i_a31_dma_cfg = {
> .nr_max_channels = 16,
> .nr_max_requests = 30,
> .nr_max_vchans = 53,
> + .dmac_variant = DMAC_VARIANT_A31,
> };
>
> /*
> @@ -1009,23 +1029,29 @@ static struct sun6i_dma_config sun8i_a23_dma_cfg = {
> .nr_max_channels = 8,
> .nr_max_requests = 24,
> .nr_max_vchans = 37,
> + .dmac_variant = DMAC_VARIANT_A23,
> };
>
> static struct sun6i_dma_config sun8i_a83t_dma_cfg = {
> .nr_max_channels = 8,
> .nr_max_requests = 28,
> .nr_max_vchans = 39,
> + .dmac_variant = DMAC_VARIANT_A23,
> };
>
> /*
> * The H3 has 12 physical channels, a maximum DRQ port id of 27,
> * and a total of 34 usable source and destination endpoints.
> + * It also supports additional burst lengths and bus widths,
> + * and the burst length fields have different offsets.
> */
>
> static struct sun6i_dma_config sun8i_h3_dma_cfg = {
> .nr_max_channels = 12,
> .nr_max_requests = 27,
> .nr_max_vchans = 34,
> + .dmac_variant = DMAC_VARIANT_H3,
> +};
> };
>
> static const struct of_device_id sun6i_dma_match[] = {
> @@ -1177,11 +1203,13 @@ static int sun6i_dma_probe(struct platform_device *pdev)
> /*
> * 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.
> + * in the A23 user manual, but appears in e.g. the H83T manual.
> + * For the H3, H5 and A64, the register has a different location
> */
> - if (of_device_is_compatible(pdev->dev.of_node,
> - "allwinner,sun8i-a23-dma"))
> + if (sdc->cfg->dmac_variant == DMAC_VARIANT_A23)
> writel(SUN8I_DMA_GATE_ENABLE, sdc->base + SUN8I_DMA_GATE);
> + else if (sdc->cfg->dmac_variant == DMAC_VARIANT_H3)
> + writel(SUNXI_H3_DMA_GATE_ENABLE, sdc->base + SUNXI_H3_DMA_GATE);
>
> return 0;
>
>