From: Maxime Ripard <mripard@kernel.org>
To: Chen-Yu Tsai <wens@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
Chen-Yu Tsai <wens@csie.org>, Rob Herring <robh+dt@kernel.org>,
Sakari Ailus <sakari.ailus@linux.intel.com>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
linux-arm-kernel@lists.infradead.org,
linux-media@vger.kernel.org
Subject: Re: [PATCH 05/14] media: sun4i-csi: Deal with DRAM offset
Date: Mon, 16 Dec 2019 14:38:14 +0100 [thread overview]
Message-ID: <20191216133814.hozcgdrnqe6tim36@gilmour.lan> (raw)
In-Reply-To: <20191215165924.28314-6-wens@kernel.org>
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On Mon, Dec 16, 2019 at 12:59:15AM +0800, Chen-Yu Tsai wrote:
> From: Chen-Yu Tsai <wens@csie.org>
>
> On Allwinner SoCs, some high memory bandwidth devices do DMA directly
> over the memory bus (called MBUS), instead of the system bus. These
> devices include the CSI camera sensor interface, video (codec) engine,
> display subsystem, etc.. The memory bus has a different addressing
> scheme without the DRAM starting offset.
>
> Deal with this using the "interconnects" property from the device tree,
> or if that is not available, set dev->dma_pfn_offset to PHYS_PFN_OFFSET.
>
> Fixes: 577bbf23b758 ("media: sunxi: Add A10 CSI driver")
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
> ---
> .../platform/sunxi/sun4i-csi/sun4i_csi.c | 22 +++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
> index f36dc6258900..b8b07c1de2a8 100644
> --- a/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
> +++ b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
> @@ -11,6 +11,7 @@
> #include <linux/module.h>
> #include <linux/mutex.h>
> #include <linux/of.h>
> +#include <linux/of_device.h>
> #include <linux/of_graph.h>
> #include <linux/platform_device.h>
> #include <linux/pm_runtime.h>
> @@ -155,6 +156,27 @@ static int sun4i_csi_probe(struct platform_device *pdev)
> subdev = &csi->subdev;
> vdev = &csi->vdev;
>
> + /*
> + * On Allwinner SoCs, some high memory bandwidth devices do DMA
> + * directly over the memory bus (called MBUS), instead of the
> + * system bus. The memory bus has a different addressing scheme
> + * without the DRAM starting offset.
> + *
> + * In some cases this can be described by an interconnect in
> + * the device tree. In other cases where the hardware is not
> + * fully understood and the interconnect is left out of the
> + * device tree, fall back to a default offset.
> + */
Though we should probably mention the DT-backward-compatibility case
here too.
Maxime
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next prev parent reply other threads:[~2019-12-16 13:38 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-15 16:59 [PATCH 00/14] media: sun4i-csi: A10/A20 CSI1 and R40 CSI0 support Chen-Yu Tsai
2019-12-15 16:59 ` [PATCH 01/14] dt-bindings: media: sun4i-csi: Add compatible for CSI1 on A10/A20 Chen-Yu Tsai
2019-12-16 10:30 ` Maxime Ripard
2019-12-19 23:56 ` Rob Herring
2019-12-15 16:59 ` [PATCH 02/14] dt-bindings: media: sun4i-csi: Add compatible for CSI0 on R40 Chen-Yu Tsai
2019-12-16 10:30 ` Maxime Ripard
2019-12-19 23:57 ` Rob Herring
2019-12-15 16:59 ` [PATCH 03/14] media: sun4i-csi: Fix data sampling polarity handling Chen-Yu Tsai
2019-12-16 13:36 ` Maxime Ripard
2019-12-15 16:59 ` [PATCH 04/14] media: sun4i-csi: Fix [HV]sync " Chen-Yu Tsai
2019-12-16 13:37 ` Maxime Ripard
2023-01-16 10:03 ` Oleg Verych
2023-01-16 10:16 ` Maxime Ripard
2023-01-16 18:43 ` Oleg Verych
2019-12-15 16:59 ` [PATCH 05/14] media: sun4i-csi: Deal with DRAM offset Chen-Yu Tsai
2019-12-16 13:38 ` Maxime Ripard [this message]
2019-12-15 16:59 ` [PATCH 06/14] media: sun4i-csi: Add support for A10 CSI1 camera sensor interface Chen-Yu Tsai
2019-12-16 13:38 ` Maxime Ripard
2020-01-02 11:33 ` Sakari Ailus
2020-01-02 11:36 ` Chen-Yu Tsai
2019-12-15 16:59 ` [PATCH 07/14] ARM: dts: sun4i: Add CSI1 controller and pinmux options Chen-Yu Tsai
2019-12-15 16:59 ` [PATCH 08/14] ARM: dts: sun7i: " Chen-Yu Tsai
2019-12-15 16:59 ` [PATCH 09/14] ARM: dts: sun8i: r40: Add I2C " Chen-Yu Tsai
2019-12-16 10:29 ` Maxime Ripard
2019-12-15 16:59 ` [PATCH 10/14] dt-bindings: bus: sunxi: Add R40 MBUS compatible Chen-Yu Tsai
2019-12-19 23:58 ` Rob Herring
2019-12-15 16:59 ` [PATCH 11/14] ARM: dts: sun8i: r40: Add device node for CSI0 Chen-Yu Tsai
2019-12-16 13:39 ` Maxime Ripard
2019-12-16 13:42 ` Chen-Yu Tsai
2019-12-16 13:53 ` Maxime Ripard
2019-12-15 16:59 ` [PATCH 12/14] [DO NOT MERGE] ARM: dts: sun4i: cubieboard: Enable OV7670 camera on CSI1 Chen-Yu Tsai
2019-12-15 16:59 ` [PATCH 13/14] [DO NOT MERGE] ARM: dts: sun7i: cubieboard2: " Chen-Yu Tsai
2019-12-15 16:59 ` [PATCH 14/14] [DO NOT MERGE] ARM: dts: sun8i-r40: bananapi-m2-ultra: Enable OV5640 camera Chen-Yu Tsai
2020-01-01 10:20 ` [PATCH 00/14] media: sun4i-csi: A10/A20 CSI1 and R40 CSI0 support Chen-Yu Tsai
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