Re: [PATCH v6] mailbox: mtk-cmdq: fix gce timeout issue

[CK Hu (胡俊光)]

Hi, Yongqiang:

On Wed, 2022-09-28 at 16:15 +0800, Yongqiang Niu wrote:
> 1. enable gce ddr enable(gce reigster offset 0x48, bit 16 to 18) when
> gce work,
> and disable gce ddr enable when gce work job done
> 2. add cmdq ddr enable/disable api, and control gce ddr
> enable/disable
> to make sure it could protect when cmdq is multiple used by display
> and mdp
> 
> this is only for some SOC which has flag "gce_ddr_en".
> for this kind of gce, there is a handshake flow between gce and ddr
> hardware,
> if not set ddr enable flag of gce, ddr will fall into idle mode,
> then gce instructions will not process done.
> we need set this flag of gce to tell ddr when gce is idle or busy
> controlled by software flow.
> 
> ddr problem is a special case.
> when test suspend/resume case, gce sometimes will pull ddr, and ddr
> can
> not go to suspend.
> if we set gce register 0x48 to 0x7, will fix this gce pull ddr issue,
> as you have referred [1] and [2] (8192 and 8195)
> but for mt8186, the gce is more special, except setting of [1] and
> [2],
> we need add more setting set gce register 0x48 to (0x7 << 16 | 0x7)
> when gce working to make sure gce could process all instructions ok.
> this case just need normal bootup, if we not set this, display cmdq
> task will timeout, and chrome homescreen will always black screen.

I think you should break this patch into three patches:

1. Add 0x48 [18:16] setting support for bootup (I don't know how to say
this)
2. Add gce ddr enable support
3. Add mt8168 gce support

Regards,
CK

> 
> and with this patch, we have done these test on mt8186:
> 1.suspend/resume
> 2.boot up to home screen
> 3.playback video with youtube.
> 
> suspend issue is special gce hardware issue, gce client  driver
> command already process done, but gce still pull ddr.
> 
> Signed-off-by: Yongqiang Niu <yongqiang.niu@xxxxxxxxxxxx>
> 
> ---
> change since v5:
> 1. adjust gce software control and ddr enable setting reviewed in v5
> 2. correct GCE_CTRL_BY_SW definitaion type error
> ---
> 
> ---
>  drivers/mailbox/mtk-cmdq-mailbox.c | 42
> +++++++++++++++++++++++++++++-
>  1 file changed, 41 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mailbox/mtk-cmdq-mailbox.c
> b/drivers/mailbox/mtk-cmdq-mailbox.c
> index 9465f9081515..ce3c595353d7 100644
> --- a/drivers/mailbox/mtk-cmdq-mailbox.c
> +++ b/drivers/mailbox/mtk-cmdq-mailbox.c
> @@ -38,6 +38,8 @@
>  #define CMDQ_THR_PRIORITY		0x40
>  
>  #define GCE_GCTL_VALUE			0x48
> +#define GCE_CTRL_BY_SW				GENMASK(2, 0)
> +#define GCE_DDR_EN				GENMASK(18, 16)
>  
>  #define CMDQ_THR_ACTIVE_SLOT_CYCLES	0x3200
>  #define CMDQ_THR_ENABLED		0x1
> @@ -80,6 +82,7 @@ struct cmdq {
>  	bool			suspended;
>  	u8			shift_pa;
>  	bool			control_by_sw;
> +	bool			sw_ddr_en;
>  	u32			gce_num;
>  };
>  
> @@ -87,9 +90,25 @@ struct gce_plat {
>  	u32 thread_nr;
>  	u8 shift;
>  	bool control_by_sw;
> +	bool sw_ddr_en;
>  	u32 gce_num;
>  };
>  
> +static void cmdq_sw_ddr_enable(struct cmdq *cmdq, bool enable)
> +{
> +	if (!cmdq->sw_ddr_en)
> +		return;
> +
> +	WARN_ON(clk_bulk_enable(cmdq->gce_num, cmdq->clocks));
> +
> +	if (enable)
> +		writel(GCE_DDR_EN | GCE_CTRL_BY_SW, cmdq->base +
> GCE_GCTL_VALUE);
> +	else
> +		writel(GCE_CTRL_BY_SW, cmdq->base + GCE_GCTL_VALUE);
> +
> +	clk_bulk_disable(cmdq->gce_num, cmdq->clocks);
> +}
> +
>  u8 cmdq_get_shift_pa(struct mbox_chan *chan)
>  {
>  	struct cmdq *cmdq = container_of(chan->mbox, struct cmdq,
> mbox);
> @@ -129,7 +148,11 @@ static void cmdq_init(struct cmdq *cmdq)
>  
>  	WARN_ON(clk_bulk_enable(cmdq->gce_num, cmdq->clocks));
>  	if (cmdq->control_by_sw)
> -		writel(0x7, cmdq->base + GCE_GCTL_VALUE);
> +		writel(GCE_CTRL_BY_SW, cmdq->base + GCE_GCTL_VALUE);
> +
> +	if (cmdq->sw_ddr_en)
> +		writel(GCE_DDR_EN | GCE_CTRL_BY_SW, cmdq->base +
> GCE_GCTL_VALUE);
> +
>  	writel(CMDQ_THR_ACTIVE_SLOT_CYCLES, cmdq->base +
> CMDQ_THR_SLOT_CYCLES);
>  	for (i = 0; i <= CMDQ_MAX_EVENT; i++)
>  		writel(i, cmdq->base + CMDQ_SYNC_TOKEN_UPDATE);
> @@ -311,6 +334,8 @@ static int cmdq_suspend(struct device *dev)
>  	if (task_running)
>  		dev_warn(dev, "exist running task(s) in suspend\n");
>  
> +	cmdq_sw_ddr_enable(cmdq, false);
> +
>  	clk_bulk_unprepare(cmdq->gce_num, cmdq->clocks);
>  
>  	return 0;
> @@ -322,6 +347,9 @@ static int cmdq_resume(struct device *dev)
>  
>  	WARN_ON(clk_bulk_prepare(cmdq->gce_num, cmdq->clocks));
>  	cmdq->suspended = false;
> +
> +	cmdq_sw_ddr_enable(cmdq, true);
> +
>  	return 0;
>  }
>  
> @@ -329,6 +357,8 @@ static int cmdq_remove(struct platform_device
> *pdev)
>  {
>  	struct cmdq *cmdq = platform_get_drvdata(pdev);
>  
> +	cmdq_sw_ddr_enable(cmdq, false);
> +
>  	clk_bulk_unprepare(cmdq->gce_num, cmdq->clocks);
>  	return 0;
>  }
> @@ -543,6 +573,7 @@ static int cmdq_probe(struct platform_device
> *pdev)
>  	cmdq->thread_nr = plat_data->thread_nr;
>  	cmdq->shift_pa = plat_data->shift;
>  	cmdq->control_by_sw = plat_data->control_by_sw;
> +	cmdq->sw_ddr_en = plat_data->sw_ddr_en;
>  	cmdq->gce_num = plat_data->gce_num;
>  	cmdq->irq_mask = GENMASK(cmdq->thread_nr - 1, 0);
>  	err = devm_request_irq(dev, cmdq->irq, cmdq_irq_handler,
> IRQF_SHARED,
> @@ -660,9 +691,18 @@ static const struct gce_plat gce_plat_v6 = {
>  	.gce_num = 2
>  };
>  
> +static const struct gce_plat gce_plat_v7 = {
> +	.thread_nr = 24,
> +	.shift = 3,
> +	.control_by_sw = true,
> +	.sw_ddr_en = true,
> +	.gce_num = 1
> +};
> +
>  static const struct of_device_id cmdq_of_ids[] = {
>  	{.compatible = "mediatek,mt8173-gce", .data = (void
> *)&gce_plat_v2},
>  	{.compatible = "mediatek,mt8183-gce", .data = (void
> *)&gce_plat_v3},
> +	{.compatible = "mediatek,mt8186-gce", .data = (void
> *)&gce_plat_v7},
>  	{.compatible = "mediatek,mt6779-gce", .data = (void
> *)&gce_plat_v4},
>  	{.compatible = "mediatek,mt8192-gce", .data = (void
> *)&gce_plat_v5},
>  	{.compatible = "mediatek,mt8195-gce", .data = (void
> *)&gce_plat_v6},