linux-kernel - Re: [PATCH v9, 2/4] mailbox: mtk-cmdq: add gce software ddr enable private data

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Message-ID: <ded0300b-5b54-48eb-038e-102ae91573c5@collabora.com>
Date:   Thu, 6 Oct 2022 11:29:33 +0200
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     Yongqiang Niu <yongqiang.niu@...iatek.com>,
        CK Hu <ck.hu@...iatek.com>,
        Chun-Kuang Hu <chunkuang.hu@...nel.org>
Cc:     Jassi Brar <jassisinghbrar@...il.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org,
        Project_Global_Chrome_Upstream_Group@...iatek.com,
        Hsin-Yi Wang <hsinyi@...omium.org>
Subject: Re: [PATCH v9, 2/4] mailbox: mtk-cmdq: add gce software ddr enable
 private data

Il 06/10/22 06:34, Yongqiang Niu ha scritto:
> if gce work control by software, we need set software enable
> for MT8186 Soc
> 
> 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.
> 
> 0x48[2:0] means control by software
> 0x48[18:16] means ddr enable
> 0x48[2:0] is pre-condition of 0x48[18:16].
> if we want set 0x48[18:16] ddr enable, 0x48[2:0] must be set at same
> time.
> and only these bits is useful, other bits is useless bits
> 
> Signed-off-by: Yongqiang Niu <yongqiang.niu@...iatek.com>
> ---
>   drivers/mailbox/mtk-cmdq-mailbox.c | 7 +++++++
>   1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/mailbox/mtk-cmdq-mailbox.c b/drivers/mailbox/mtk-cmdq-mailbox.c
> index c3cb24f51699..04eb44d89119 100644
> --- a/drivers/mailbox/mtk-cmdq-mailbox.c
> +++ b/drivers/mailbox/mtk-cmdq-mailbox.c
> @@ -39,6 +39,7 @@
>   
>   #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
> @@ -81,6 +82,7 @@ struct cmdq {
>   	bool			suspended;
>   	u8			shift_pa;
>   	bool			control_by_sw;
> +	bool			sw_ddr_en;
>   	u32			gce_num;
>   };
>   
> @@ -88,6 +90,7 @@ struct gce_plat {
>   	u32 thread_nr;
>   	u8 shift;
>   	bool control_by_sw;
> +	bool sw_ddr_en;
>   	u32 gce_num;
>   };
>   
> @@ -132,6 +135,9 @@ static void cmdq_init(struct cmdq *cmdq)
>   	if (cmdq->control_by_sw)
>   		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);
> +

No. That's redundant.
Here's a better way:

	u32 gctl_regval = 0;

	if (cmdq->control_by_sw)
		gctl_regval = GCE_CTRL_BY_SW;
	if (cmdq->sw_ddr_en)
		gctl_regval |= GCE_DDR_EN;

	if (val)
		writel(gctl_regval, cmdq->base + GCE_GCTL_VALUE);

Regards,
Angelo

>   	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);
> @@ -545,6 +551,7 @@ 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,