linux-kernel - Re: [PATCH v7 12/20] soc: mediatek: Add programming flow for unsupported subsys ID hardware

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Message-ID: <6f1f74b3-ac2e-4ea6-abce-14ef12ea10dd@collabora.com>
Date: Thu, 9 Oct 2025 13:41:28 +0200
From: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
To: Jason-JH Lin <jason-jh.lin@...iatek.com>, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, Jassi Brar <jassisinghbrar@...il.com>,
 Chun-Kuang Hu <chunkuang.hu@...nel.org>,
 Mauro Carvalho Chehab <mchehab@...nel.org>
Cc: Matthias Brugger <matthias.bgg@...il.com>,
 Nicolas Dufresne <nicolas@...fresne.ca>, Nancy Lin <nancy.lin@...iatek.com>,
 Singo Chang <singo.chang@...iatek.com>,
 Paul-PL Chen <paul-pl.chen@...iatek.com>, Moudy Ho <moudy.ho@...iatek.com>,
 Xiandong Wang <xiandong.wang@...iatek.com>,
 Sirius Wang <sirius.wang@...iatek.com>, Fei Shao <fshao@...omium.org>,
 Chen-yu Tsai <wenst@...omium.org>,
 Project_Global_Chrome_Upstream_Group@...iatek.com,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
 dri-devel@...ts.freedesktop.org, linux-mediatek@...ts.infradead.org,
 linux-arm-kernel@...ts.infradead.org, linux-media@...r.kernel.org
Subject: Re: [PATCH v7 12/20] soc: mediatek: Add programming flow for
 unsupported subsys ID hardware

Il 27/08/25 13:37, Jason-JH Lin ha scritto:
> To support hardware without subsys IDs on new SoCs, add a programming
> flow that checks whether the subsys ID is valid.
> 
> If the subsys ID is valid, the flow will call cmdq_pkt_write_subsys()
> and cmdq_pkt_write_mask_subsys() instead of the original
> cmdq_pkt_write() and cmdq_pkt_write_mask().
> 
> If the subsys ID is invalid, the flow will call cmdq_pkt_write_pa() and
> cmdq_pkt_write_mask_pa() to achieve the same functionality.
> 
> Signed-off-by: Jason-JH Lin <jason-jh.lin@...iatek.com>
> ---
>   drivers/soc/mediatek/mtk-mmsys.c | 12 +++++++++---
>   drivers/soc/mediatek/mtk-mutex.c |  8 ++++++--
>   2 files changed, 15 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/soc/mediatek/mtk-mmsys.c b/drivers/soc/mediatek/mtk-mmsys.c
> index bb4639ca0b8c..0c324846e334 100644
> --- a/drivers/soc/mediatek/mtk-mmsys.c
> +++ b/drivers/soc/mediatek/mtk-mmsys.c
> @@ -167,9 +167,15 @@ static void mtk_mmsys_update_bits(struct mtk_mmsys *mmsys, u32 offset, u32 mask,
>   	u32 tmp;
>   
>   	if (mmsys->cmdq_base.size && cmdq_pkt) {
> -		ret = cmdq_pkt_write_mask(cmdq_pkt, mmsys->cmdq_base.subsys,
> -					  mmsys->cmdq_base.offset + offset, val,
> -					  mask);
> +		offset += mmsys->cmdq_base.offset;
> +		if (mmsys->cmdq_base.subsys != CMDQ_SUBSYS_INVALID)
> +			ret = cmdq_pkt_write_mask_subsys(cmdq_pkt, mmsys->cmdq_base.subsys,
> +							 mmsys->cmdq_base.pa_base, offset,
> +							 val, mask);
> +		else /* only MMIO access, no need to check mminfro_offset */

nit: fix typo -> mminfra_offset

and also it would be nice if you could also say in a comment that all GCEs support
write_mask_pa() without subsys, but it is less performant - so for the platforms
that do support it, we prefer using it.

Of course that has to be properly reworded, but that's the idea anyway :-)

after which

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>

> +			ret = cmdq_pkt_write_mask_pa(cmdq_pkt, mmsys->cmdq_base.subsys,
> +						     mmsys->cmdq_base.pa_base, offset, val, mask);
> +
>   		if (ret)
>   			pr_debug("CMDQ unavailable: using CPU write\n");
>   		else
> diff --git a/drivers/soc/mediatek/mtk-mutex.c b/drivers/soc/mediatek/mtk-mutex.c
> index 38179e8cd98f..9b22d7e09d99 100644
> --- a/drivers/soc/mediatek/mtk-mutex.c
> +++ b/drivers/soc/mediatek/mtk-mutex.c
> @@ -990,6 +990,7 @@ int mtk_mutex_enable_by_cmdq(struct mtk_mutex *mutex, void *pkt)
>   	struct mtk_mutex_ctx *mtx = container_of(mutex, struct mtk_mutex_ctx,
>   						 mutex[mutex->id]);
>   	struct cmdq_pkt *cmdq_pkt = (struct cmdq_pkt *)pkt;
> +	dma_addr_t en_addr = mtx->addr + DISP_REG_MUTEX_EN(mutex->id);
>   
>   	WARN_ON(&mtx->mutex[mutex->id] != mutex);
>   
> @@ -998,8 +999,11 @@ int mtk_mutex_enable_by_cmdq(struct mtk_mutex *mutex, void *pkt)
>   		return -ENODEV;
>   	}
>   
> -	cmdq_pkt_write(cmdq_pkt, mtx->cmdq_reg.subsys,
> -		       mtx->addr + DISP_REG_MUTEX_EN(mutex->id), 1);
> +	if (mtx->cmdq_reg.subsys != CMDQ_SUBSYS_INVALID)
> +		cmdq_pkt_write_subsys(cmdq_pkt, mtx->cmdq_reg.subsys, en_addr, en_addr, 1);
> +	else /* only MMIO access, no need to check mminfro_offset */
> +		cmdq_pkt_write_pa(cmdq_pkt, mtx->cmdq_reg.subsys, en_addr, en_addr, 1);
> +
>   	return 0;
>   }
>   EXPORT_SYMBOL_GPL(mtk_mutex_enable_by_cmdq);