linux-kernel - Re: [PATCH] drm/rockchip: vop: do axi reset in vop initial time

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Date:	Wed, 1 Jun 2016 17:49:32 +0800
From:	Mark yao <mark.yao@...k-chips.com>
To:	Yakir Yang <ykk@...k-chips.com>, Mark Yao <yzq@...k-chips.com>,
	Heiko Stuebner <heiko@...ech.de>, tfiga@...omium.org
Cc:	David Airlie <airlied@...ux.ie>, daniel.vetter@...ll.ch,
	Thierry Reding <treding@...dia.com>, dianders@...omium.org,
	linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
	linux-rockchip@...ts.infradead.org
Subject: Re: [PATCH] drm/rockchip: vop: do axi reset in vop initial time

On 2016年06月01日 17:19, Yakir Yang wrote:
> There is a bug in RK3399 VOP, when bootloader/kernel only enable
> VOP Big or VOP Little to display, then VOP IOMMU would failed to
> reset at the initial time and VOP register couldn't write rightly.
>
> After do the pure reset of VOP module, then things back to right.
>
> Signed-off-by: Yakir Yang <ykk@...k-chips.com>
Hi Yakir

I think you get vop iommu reset failed should be IOMMU Page fault, the 
vop iommu access a ummap address.

You should ensure all vop windows access right iommu mapping address 
before attach iommu.

Actually, I'm working no flash display from bootloader to kernel, and 
prepare remove all the reset on vop initial, because it would flash the 
display.

Thanks.

> ---
>   drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 15 ++++++++++++++-
>   1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
> index 1c4d5b5..4150323 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
> @@ -1292,7 +1292,7 @@ static int vop_initial(struct vop *vop)
>   {
>   	const struct vop_data *vop_data = vop->data;
>   	const struct vop_reg_data *init_table = vop_data->init_table;
> -	struct reset_control *ahb_rst;
> +	struct reset_control *ahb_rst, *axi_rst;
>   	int i, ret;
>   
>   	vop->hclk = devm_clk_get(vop->dev, "hclk_vop");
> @@ -1331,6 +1331,19 @@ static int vop_initial(struct vop *vop)
>   	}
>   
>   	/*
> +	 * do aclk_reset, reset all vop registers.
> +	 */
> +	axi_rst = devm_reset_control_get(vop->dev, "axi");
> +	if (IS_ERR(axi_rst)) {
> +		dev_err(vop->dev, "failed to get axi reset\n");
> +		ret = PTR_ERR(axi_rst);
> +		goto err_disable_aclk;
> +	}
> +	reset_control_assert(axi_rst);
> +	usleep_range(10, 20);
> +	reset_control_deassert(axi_rst);
> +
> +	/*
>   	 * do hclk_reset, reset all vop registers.
>   	 */
>   	ahb_rst = devm_reset_control_get(vop->dev, "ahb");


-- 
Ｍark Yao