linux-kernel - Re: [PATCH 1/3] drm/mediatek: Dynamically allocate CMDQ and use helper functions

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Message-ID: <d29d342b-37f4-8d7b-ed7d-c441cc928393@collabora.com>
Date:   Thu, 3 Aug 2023 10:25:36 +0200
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     CK Hu (胡俊光) <ck.hu@...iatek.com>,
        "chunkuang.hu@...nel.org" <chunkuang.hu@...nel.org>
Cc:     "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-mediatek@...ts.infradead.org" 
        <linux-mediatek@...ts.infradead.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "kernel@...labora.com" <kernel@...labora.com>,
        "matthias.bgg@...il.com" <matthias.bgg@...il.com>,
        "wenst@...omium.org" <wenst@...omium.org>
Subject: Re: [PATCH 1/3] drm/mediatek: Dynamically allocate CMDQ and use
 helper functions

Il 03/08/23 08:28, CK Hu (胡俊光) ha scritto:
> Hi, Angelo:
> 
> On Wed, 2023-08-02 at 12:41 +0200, AngeloGioacchino Del Regno wrote:
>> Il 02/08/23 08:24, CK Hu (胡俊光) ha scritto:
>>> Hi, Angelo:
>>>
>>> On Fri, 2023-06-23 at 11:49 +0200, AngeloGioacchino Del Regno
>>> wrote:
>>>>    	
>>>> External email : Please do not click links or open attachments
>>>> until
>>>> you have verified the sender or the content.
>>>>    Instead of stack allocating the cmdq_client and cmdq_handle
>>>> structures
>>>> switch them to pointers, allowing us to migrate this driver to
>>>> use
>>>> the
>>>> common functions provided by mtk-cmdq-helper.
>>>> In order to do this, it was also necessary to add a `priv`
>>>> pointer to
>>>> struct cmdq_client, as that's used to pass (in this case) a
>>>> mtk_crtc
>>>> handle to the ddp_cmdq_cb() mailbox RX callback function.
>>>>
>>>> Signed-off-by: AngeloGioacchino Del Regno <
>>>> angelogioacchino.delregno@...labora.com>
>>>> ---
>>>>    drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 107 +++++++--------
>>>> -------
>>>> --
>>>>    include/linux/soc/mediatek/mtk-cmdq.h   |   1 +
>>>>    2 files changed, 32 insertions(+), 76 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
>>>> b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
>>>> index 0df62b076f49..b63289ab6787 100644
>>>> --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
>>>> +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
>>>> @@ -50,8 +50,8 @@ struct mtk_drm_crtc {
>>>>    	bool				pending_async_planes;
>>>>    
>>>>    #if IS_REACHABLE(CONFIG_MTK_CMDQ)
>>>> -	struct cmdq_client		cmdq_client;
>>>> -	struct cmdq_pkt			cmdq_handle;
>>>> +	struct cmdq_client		*cmdq_client;
>>>> +	struct cmdq_pkt			*cmdq_handle;
>>>>    	u32				cmdq_event;
>>>>    	u32				cmdq_vblank_cnt;
>>>>    	wait_queue_head_t		cb_blocking_queue;
>>>> @@ -108,47 +108,6 @@ static void mtk_drm_finish_page_flip(struct
>>>> mtk_drm_crtc *mtk_crtc)
>>>>    	}
>>>>    }
>>>>    
>>>> -#if IS_REACHABLE(CONFIG_MTK_CMDQ)
>>>> -static int mtk_drm_cmdq_pkt_create(struct cmdq_client *client,
>>>> struct cmdq_pkt *pkt,
>>>> -				   size_t size)
>>>> -{
>>>> -	struct device *dev;
>>>> -	dma_addr_t dma_addr;
>>>> -
>>>> -	pkt->va_base = kzalloc(size, GFP_KERNEL);
>>>> -	if (!pkt->va_base) {
>>>> -		kfree(pkt);
>>>> -		return -ENOMEM;
>>>> -	}
>>>> -	pkt->buf_size = size;
>>>> -	pkt->cl = (void *)client;
>>>
>>> I have a plan to remove cl in struct cmdq_pkt. But this
>>> modification
>>> would make this plan more difficult. So I would pending this patch
>>> until cl is removed from struct cmdq_pkt.
>>>
>>
>> I think that this ifdef cleanup is more urgent than the removal of
>> `cl` from
>> struct cmdq_pkt, as those ifdefs shouldn't have reached upstream in
>> the first
>> place, don't you agree?
> 
> I think removing ifdefs and using helper function are different things.
> You could remove ifdefs and keep mtk_drm_cmdq_pkt_create().
> 

I chose to do it like that because this function would otherwise be a
100% duplicate of the related cmdq helper :-)


> Regards,
> CK
> 
>>
>> Regards,
>> Angelo
>>