linux-kernel - Re: [PATCH 15/18] drm/mediatek: add RDMA1 fifo size into RDMA private data

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Date:   Thu, 27 Dec 2018 16:08:56 +0800
From:   CK Hu <ck.hu@...iatek.com>
To:     Yongqiang Niu <yongqiang.niu@...iatek.com>
CC:     Philipp Zabel <p.zabel@...gutronix.de>,
        David Airlie <airlied@...ux.ie>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        <dri-devel@...ts.freedesktop.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>
Subject: Re: [PATCH 15/18] drm/mediatek: add RDMA1 fifo size into RDMA
 private data

Hi, Yongqiang:

On Mon, 2018-12-24 at 16:08 +0800, Yongqiang Niu wrote:
> This patch add RDMA1 fifo size into RDMA private data
> 
> Signed-off-by: Yongqiang Niu <yongqiang.niu@...iatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_disp_rdma.c | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
> index b0a5cff..3f9b4d4 100644
> --- a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
> +++ b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
> @@ -53,12 +53,14 @@
>  #define RDMA_FIFO_PSEUDO_SIZE(bytes)			(((bytes) / 16) << 16)
>  #define RDMA_OUTPUT_VALID_FIFO_THRESHOLD(bytes)		((bytes) / 16)
>  #define RDMA_FIFO_SIZE(rdma)			((rdma)->data->fifo_size)
> +#define RDMA_FIFO_SIZE1(rdma)			((rdma)->data->fifo_size1)
>  #define DISP_RDMA_MEM_START_ADDR		0x0f00
>  
>  #define RDMA_MEM_GMC				0x40402020
>  
>  struct mtk_disp_rdma_data {
>  	unsigned int fifo_size;
> +	unsigned int fifo_size1;
>  };
>  
>  /**
> @@ -137,11 +139,17 @@ static void mtk_rdma_config(struct mtk_ddp_comp *comp, unsigned int width,
>  {
>  	unsigned int threshold;
>  	unsigned int reg;
> +	unsigned int rdma_fifo_size;
>  	struct mtk_disp_rdma *rdma = comp_to_rdma(comp);
>  
>  	rdma_update_bits(comp, DISP_REG_RDMA_SIZE_CON_0, 0xfff, width);
>  	rdma_update_bits(comp, DISP_REG_RDMA_SIZE_CON_1, 0xfffff, height);
>  
> +	if (comp->id == DDP_COMPONENT_RDMA1)
> +		rdma_fifo_size = RDMA_FIFO_SIZE1(rdma);
> +	else
> +		rdma_fifo_size = RDMA_FIFO_SIZE(rdma);
> +

It looks like that mt81830-rdma0 and mt8183-rdma1 are different in
hardware, so I think fifo_size should be decided by something from
device tree rather than from its name. Maybe add a property 'FIFO_SIZE'
in rdma device node or create an additional compatible string for
mt8183-rdma1.

Regards,
CK

>  	/*
>  	 * Enable FIFO underflow since DSI and DPI can't be blocked.
>  	 * Keep the FIFO pseudo size reset default of 8 KiB. Set the
> @@ -149,8 +157,12 @@ static void mtk_rdma_config(struct mtk_ddp_comp *comp, unsigned int width,
>  	 * account for blanking, and with a pixel depth of 4 bytes:
>  	 */
>  	threshold = width * height * vrefresh * 4 * 7 / 1000000;
> +
> +	if (threshold > rdma_fifo_size)
> +		threshold = rdma_fifo_size;
> +
>  	reg = RDMA_FIFO_UNDERFLOW_EN |
> -	      RDMA_FIFO_PSEUDO_SIZE(RDMA_FIFO_SIZE(rdma)) |
> +	      RDMA_FIFO_PSEUDO_SIZE(rdma_fifo_size) |
>  	      RDMA_OUTPUT_VALID_FIFO_THRESHOLD(threshold);
>  	writel(reg, comp->regs + DISP_REG_RDMA_FIFO_CON);
>  }
> @@ -330,10 +342,12 @@ static int mtk_disp_rdma_remove(struct platform_device *pdev)
>  
>  static const struct mtk_disp_rdma_data mt2701_rdma_driver_data = {
>  	.fifo_size = SZ_4K,
> +	.fifo_size1 = SZ_4K,
>  };
>  
>  static const struct mtk_disp_rdma_data mt8173_rdma_driver_data = {
>  	.fifo_size = SZ_8K,
> +	.fifo_size1 = SZ_8K,
>  };
>  
>  static const struct of_device_id mtk_disp_rdma_driver_dt_match[] = {