On Mon, Jun 05, 2017 at 08:33:47PM +0800, Icenowy Zheng wrote:
> From: Icenowy Zheng <icen...@aosc.xyz>
>
> 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 <icen...@aosc.xyz>
> ---
> 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?
> };
>
> /*
> @@ -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
>
--
~Vinod
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