linux-kernel - Re: [PATCH 2/2] drm/v3d: client ranges from axi

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Message-ID: <efbd7d18-1cd2-4eb9-b504-c4a75370843a@igalia.com>
Date: Thu, 10 Apr 2025 09:40:45 -0300
From: Maíra Canal <mcanal@...lia.com>
To: Jose Maria Casanova Crespo <jmcasanova@...lia.com>,
 Melissa Wen <mwen@...lia.com>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] drm/v3d: client ranges from axi_ids are different
 with V3D 7.1

Hi Chema,

On 09/04/25 12:55, Jose Maria Casanova Crespo wrote:
> The client mask has been reduced from 8 bits on V3D 4.1 to 7 bits
> on V3d 7.1, so the ranges for each client are not compatible.

s/V3d/V3D

> 
> A new CSD client can now report MMU errors on 7.1

How about "On V3D 7.1, the CSD client can also report MMU errors.
Therefore, add its AXI ID to the IDs list."?

Note that a commit message should use the imperative mood:

"Describe your changes in imperative mood, e.g. “make xyzzy do frotz”
instead of “[This patch] makes xyzzy do frotz” or “[I] changed xyzzy to
do frotz”, as if you are giving orders to the codebase to change its
behaviour." [1]

I miss such imperative description in this commit message.

Also, you could add a "Fixes:" tag pointing to the commit that
introduced V3D 7.1. This will allow this commit to go to the stable
trees.

[1] https://docs.kernel.org/process/submitting-patches.html

> 
> Signed-off-by: Jose Maria Casanova Crespo <jmcasanova@...lia.com>
> ---
>   drivers/gpu/drm/v3d/v3d_irq.c | 21 ++++++++++++++++++++-
>   1 file changed, 20 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/v3d/v3d_irq.c b/drivers/gpu/drm/v3d/v3d_irq.c
> index 1810743ea7b8..0cc1c7e5b412 100644
> --- a/drivers/gpu/drm/v3d/v3d_irq.c
> +++ b/drivers/gpu/drm/v3d/v3d_irq.c
> @@ -199,12 +199,31 @@ v3d_hub_irq(int irq, void *arg)
>   			{0xA0, 0xA1, "TFU"},
>   			{0xC0, 0xE0, "MMU"},
>   			{0xE0, 0xE1, "GMP"},
> +		}, v3d71_axi_ids[] = {
> +			{0x00, 0x30, "L2T"},
> +			{0x30, 0x38, "CLE"},
> +			{0x38, 0x39, "PTB"},
> +			{0x39, 0x3A, "PSE"},
> +			{0x3A, 0x3B, "CSD"},
> +			{0x40, 0x60, "TLB"},
> +			{0x60, 0x70, "MMU"},
> +			{0x7C, 0x7E, "TFU"},
> +			{0x7F, 0x80, "GMP"},
>   		};
>   		const char *client = "?";
>   
>   		V3D_WRITE(V3D_MMU_CTL, V3D_READ(V3D_MMU_CTL));
>   
> -		if (v3d->ver >= V3D_GEN_41) {
> +		if (v3d->ver >= V3D_GEN_71) {
> +			axi_id = axi_id & 0x7F;
> +			for (size_t i = 0; i < ARRAY_SIZE(v3d71_axi_ids); i++) {
> +				if (axi_id >= v3d71_axi_ids[i].begin &&
> +				    axi_id < v3d71_axi_ids[i].end) {
> +					client = v3d71_axi_ids[i].client;
> +					break;
> +				}
> +			}

What do you think about assigning v3d71_axi_ids or v3d41_axi_ids to an 
temporary variable and move this loop below? Something like,

if (v3d->ver >= V3D_GEN_71) {
	axi_id = axi_id & 0x7F;
	v3d_axi_ids = v3d71_axi_ids;
} else if ... {
	...
}

for (size_t i = 0; i < ARRAY_SIZE(v3d_axi_ids); i++) {
	if (axi_id >= v3d_axi_ids[i].begin
	    && axi_id < v3d_axi_ids[i].end) {
		client = v3d_axi_ids[i].client;
		break;
	}
}

Best Regards,
- Maíra

> +		} else if (v3d->ver >= V3D_GEN_41) {
>   			axi_id = axi_id & 0xFF;
>   			for (size_t i = 0; i < ARRAY_SIZE(v3d41_axi_ids); i++) {
>   				if (axi_id >= v3d41_axi_ids[i].begin &&