linux-kernel - Re: [PATCH v2 5/6] soc: mediatek: devapc: add debug register for new IC support

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Date:   Tue, 6 Apr 2021 15:53:16 +0200
From:   Matthias Brugger <matthias.bgg@...il.com>
To:     Nina Wu <nina-cm.wu@...iatek.com>, Rob Herring <robh+dt@...nel.org>
Cc:     Zhen Lei <thunder.leizhen@...wei.com>,
        Neal Liu <neal.liu@...iatek.com>, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, srv_heupstream@...iatek.com,
        Jackson-kt.Chang@...iatek.com
Subject: Re: [PATCH v2 5/6] soc: mediatek: devapc: add debug register for new
 IC support



On 01/04/2021 08:38, Nina Wu wrote:
> From: Nina Wu <Nina-CM.Wu@...iatek.com>
> 
> There are 3 debug info registers in new ICs while in legacy ones,
> we have only 2. When dumping the debug info, we need to check first
> if the 3rd debug register exists and then we can konw how to decipher
> the debug info.
> 
> Signed-off-by: Nina Wu <Nina-CM.Wu@...iatek.com>
> ---
>  drivers/soc/mediatek/mtk-devapc.c | 31 +++++++++++++++++++++++++++++--
>  1 file changed, 29 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/soc/mediatek/mtk-devapc.c b/drivers/soc/mediatek/mtk-devapc.c
> index bcf6e3c..af55c01 100644
> --- a/drivers/soc/mediatek/mtk-devapc.c
> +++ b/drivers/soc/mediatek/mtk-devapc.c
> @@ -26,9 +26,19 @@ struct mtk_devapc_vio_dbgs {
>  			u32 addr_h:4;
>  			u32 resv:4;
>  		} dbg0_bits;
> +
> +		/* Not used, reference only */
> +		struct {
> +			u32 dmnid:6;
> +			u32 vio_w:1;
> +			u32 vio_r:1;
> +			u32 addr_h:4;
> +			u32 resv:20;
> +		} dbg0_bits_ver2;
>  	};
>  
>  	u32 vio_dbg1;
> +	u32 vio_dbg2;
>  };
>  
>  struct mtk_devapc_data {
> @@ -37,6 +47,7 @@ struct mtk_devapc_data {
>  	u32 vio_sta_offset;
>  	u32 vio_dbg0_offset;
>  	u32 vio_dbg1_offset;
> +	u32 vio_dbg2_offset;
>  	u32 apc_con_offset;
>  	u32 vio_shift_sta_offset;
>  	u32 vio_shift_sel_offset;
> @@ -158,12 +169,29 @@ static void devapc_extract_vio_dbg(struct mtk_devapc_context *ctx)
>  	struct mtk_devapc_vio_dbgs vio_dbgs;
>  	void __iomem *vio_dbg0_reg;
>  	void __iomem *vio_dbg1_reg;
> +	void __iomem *vio_dbg2_reg;
> +	u32 vio_addr, bus_id;
>  
>  	vio_dbg0_reg = ctx->base + ctx->data->vio_dbg0_offset;
>  	vio_dbg1_reg = ctx->base + ctx->data->vio_dbg1_offset;
> +	vio_dbg2_reg = ctx->base + ctx->data->vio_dbg2_offset;

We should read this only if we have version2 of the devapc.

>  
>  	vio_dbgs.vio_dbg0 = readl(vio_dbg0_reg);
>  	vio_dbgs.vio_dbg1 = readl(vio_dbg1_reg);
> +	vio_dbgs.vio_dbg2 = readl(vio_dbg2_reg);
> +
> +	if (!ctx->data->vio_dbg2_offset) {

I think we should add a version field to mtk_devapc_data to distinguish the two
of them.

> +		/* arch version 1 */
> +		bus_id = vio_dbgs.dbg0_bits.mstid;
> +		vio_addr = vio_dbgs.vio_dbg1;
> +	} else {
> +		/* arch version 2 */
> +		bus_id = vio_dbgs.vio_dbg1;
> +		vio_addr = vio_dbgs.vio_dbg2;
> +
> +		/* To align with the bit definition of arch_ver 1 */
> +		vio_dbgs.vio_dbg0 = (vio_dbgs.vio_dbg0 << 16);

That's magic, better add another variable domain_id and do here:
domain_id = vio_dgbs.dbg0_bits_ver2.dmnid;

> +	}
>  
>  	/* Print violation information */
>  	if (vio_dbgs.dbg0_bits.vio_w)
> @@ -172,8 +200,7 @@ static void devapc_extract_vio_dbg(struct mtk_devapc_context *ctx)
>  		dev_info(ctx->dev, "Read Violation\n");
>  
>  	dev_info(ctx->dev, "Bus ID:0x%x, Dom ID:0x%x, Vio Addr:0x%x\n",
> -		 vio_dbgs.dbg0_bits.mstid, vio_dbgs.dbg0_bits.dmnid,
> -		 vio_dbgs.vio_dbg1);
> +		 bus_id, vio_dbgs.dbg0_bits.dmnid, vio_addr);
>  }
>  
>  /*
>