diff mbox series

[v2,1/4] soc: amlogic: add meson-canvas driver

Message ID 20180807220011.24436-2-maxi.jourdan@wanadoo.fr (mailing list archive)
State Not Applicable
Headers show
Series soc: amlogic: add meson-canvas | expand

Commit Message

Maxime Jourdan Aug. 7, 2018, 10 p.m. UTC
Amlogic SoCs have a repository of 256 canvas which they use to
describe pixel buffers.

They contain metadata like width, height, block mode, endianness [..]

Many IPs within those SoCs like vdec/vpu rely on those canvas to read/write
pixels.

Signed-off-by: Maxime Jourdan <maxi.jourdan@wanadoo.fr>
Tested-by: Neil Armstrong <narmstrong@baylibre.com>
---
 drivers/soc/amlogic/Kconfig              |   7 +
 drivers/soc/amlogic/Makefile             |   1 +
 drivers/soc/amlogic/meson-canvas.c       | 185 +++++++++++++++++++++++
 include/linux/soc/amlogic/meson-canvas.h |  65 ++++++++
 4 files changed, 258 insertions(+)
 create mode 100644 drivers/soc/amlogic/meson-canvas.c
 create mode 100644 include/linux/soc/amlogic/meson-canvas.h

Comments

Jerome Brunet Aug. 8, 2018, 7:45 a.m. UTC | #1
On Wed, 2018-08-08 at 00:00 +0200, Maxime Jourdan wrote:
> Amlogic SoCs have a repository of 256 canvas which they use to
> describe pixel buffers.
> 
> They contain metadata like width, height, block mode, endianness [..]
> 
> Many IPs within those SoCs like vdec/vpu rely on those canvas to read/write
> pixels.
> 
> Signed-off-by: Maxime Jourdan <maxi.jourdan@wanadoo.fr>
> Tested-by: Neil Armstrong <narmstrong@baylibre.com>

Thanks for making the changes Martin, I do prefer this version. You did not have
to drop the ops, until it is really needed because of some SoC quirks, I guess
it is simpler this way

With some answers to the nitpicks below, feel free to add :

Reviewed-by: Jerome Brunet <jbrunet@baylibre.com>

> ---
>  drivers/soc/amlogic/Kconfig              |   7 +
>  drivers/soc/amlogic/Makefile             |   1 +
>  drivers/soc/amlogic/meson-canvas.c       | 185 +++++++++++++++++++++++
>  include/linux/soc/amlogic/meson-canvas.h |  65 ++++++++
>  4 files changed, 258 insertions(+)
>  create mode 100644 drivers/soc/amlogic/meson-canvas.c
>  create mode 100644 include/linux/soc/amlogic/meson-canvas.h
> 
> diff --git a/drivers/soc/amlogic/Kconfig b/drivers/soc/amlogic/Kconfig
> index b04f6e4aedbc..2f282b472912 100644
> --- a/drivers/soc/amlogic/Kconfig
> +++ b/drivers/soc/amlogic/Kconfig
> @@ -1,5 +1,12 @@
>  menu "Amlogic SoC drivers"
>  
> +config MESON_CANVAS
> +	tristate "Amlogic Meson Canvas driver"
> +	depends on ARCH_MESON || COMPILE_TEST
> +	default n
> +	help
> +	  Say yes to support the canvas IP for Amlogic SoCs.
> +
>  config MESON_GX_SOCINFO
>  	bool "Amlogic Meson GX SoC Information driver"
>  	depends on ARCH_MESON || COMPILE_TEST
> diff --git a/drivers/soc/amlogic/Makefile b/drivers/soc/amlogic/Makefile
> index 8fa321893928..0ab16d35ac36 100644
> --- a/drivers/soc/amlogic/Makefile
> +++ b/drivers/soc/amlogic/Makefile
> @@ -1,3 +1,4 @@
> +obj-$(CONFIG_MESON_CANVAS) += meson-canvas.o
>  obj-$(CONFIG_MESON_GX_SOCINFO) += meson-gx-socinfo.o
>  obj-$(CONFIG_MESON_GX_PM_DOMAINS) += meson-gx-pwrc-vpu.o
>  obj-$(CONFIG_MESON_MX_SOCINFO) += meson-mx-socinfo.o
> diff --git a/drivers/soc/amlogic/meson-canvas.c b/drivers/soc/amlogic/meson-canvas.c
> new file mode 100644
> index 000000000000..c461334b36d4
> --- /dev/null
> +++ b/drivers/soc/amlogic/meson-canvas.c
> @@ -0,0 +1,185 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2018 Maxime Jourdan <maxi.jourdan@wanadoo.fr>
> + * Copyright (C) 2016 BayLibre, SAS
> + * Author: Neil Armstrong <narmstrong@baylibre.com>
> + * Copyright (C) 2015 Amlogic, Inc. All rights reserved.
> + * Copyright (C) 2014 Endless Mobile
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +#include <linux/soc/amlogic/meson-canvas.h>
> +#include <linux/of_address.h>
> +#include <linux/of_platform.h>
> +#include <linux/io.h>
> +
> +#define NUM_CANVAS 256
> +
> +/* DMC Registers */
> +#define DMC_CAV_LUT_DATAL	0x48 /* 0x12 offset in data sheet */
> +	#define CANVAS_WIDTH_LBIT	29
> +	#define CANVAS_WIDTH_LWID       3
> +#define DMC_CAV_LUT_DATAH	0x4c /* 0x13 offset in data sheet */
> +	#define CANVAS_WIDTH_HBIT       0
> +	#define CANVAS_HEIGHT_BIT       9
> +	#define CANVAS_BLKMODE_BIT      24
> +#define DMC_CAV_LUT_ADDR	0x50 /* 0x14 offset in data sheet */
> +	#define CANVAS_LUT_WR_EN        (0x2 << 8)
> +	#define CANVAS_LUT_RD_EN        (0x1 << 8)
> +
> +struct meson_canvas {
> +	struct device *dev;
> +	struct regmap *regmap_dmc;
> +	spinlock_t lock; /* canvas device lock */
> +	u8 used[NUM_CANVAS];
> +};
> +
> +struct meson_canvas *meson_canvas_get(struct device *dev)
> +{
> +	struct device_node *canvas_node;
> +	struct platform_device *canvas_pdev;
> +	struct meson_canvas *canvas;
> +
> +	canvas_node = of_parse_phandle(dev->of_node, "amlogic,canvas", 0);
> +	if (!canvas_node)
> +		return ERR_PTR(-ENODEV);
> +
> +	canvas_pdev = of_find_device_by_node(canvas_node);
> +	if (!canvas_pdev) {
> +		dev_err(dev, "Unable to find canvas pdev\n");
> +		return ERR_PTR(-ENODEV);
> +	}
> +
> +	canvas = dev_get_drvdata(&canvas_pdev->dev);
> +	if (!canvas)
> +		return ERR_PTR(-ENODEV);

You've got your device at this point, maybe EINVAL instead ?

> +
> +	return canvas;
> +}
> +EXPORT_SYMBOL_GPL(meson_canvas_get);
> +
> +int meson_canvas_setup(struct meson_canvas *canvas, u8 canvas_index,
> +		       u32 addr, u32 stride, u32 height,
> +		       unsigned int wrap,
> +		       unsigned int blkmode,
> +		       unsigned int endian)
> +{
> +	struct regmap *regmap = canvas->regmap_dmc;
> +	unsigned long flags;
> +	u32 val;
> +
> +	spin_lock_irqsave(&canvas->lock, flags);
> +	if (!canvas->used[canvas_index]) {
> +		dev_err(canvas->dev,
> +			"Trying to setup non allocated canvas %u\n",
> +			canvas_index);
> +		spin_unlock_irqrestore(&canvas->lock, flags);
> +		return -EINVAL;
> +	}
> +
> +	regmap_write(regmap, DMC_CAV_LUT_DATAL,
> +		     ((addr + 7) >> 3) |
> +		     (((stride + 7) >> 3) << CANVAS_WIDTH_LBIT));
> +
> +	regmap_write(regmap, DMC_CAV_LUT_DATAH,
> +		     ((((stride + 7) >> 3) >> CANVAS_WIDTH_LWID) <<
> +						CANVAS_WIDTH_HBIT) |
> +		     (height << CANVAS_HEIGHT_BIT) |
> +		     (wrap << 22) |
> +		     (blkmode << CANVAS_BLKMODE_BIT) |
> +		     (endian << 26));
> +
> +	regmap_write(regmap, DMC_CAV_LUT_ADDR,
> +		     CANVAS_LUT_WR_EN | canvas_index);
> +
> +	/* Force a read-back to make sure everything is flushed. */
> +	regmap_read(regmap, DMC_CAV_LUT_DATAH, &val);

I suppose this something you got from the vendor kernel ? Out of curiosity, have
you tried w/o it ? I am wondering if this is really necessary ? 


> +	spin_unlock_irqrestore(&canvas->lock, flags);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(meson_canvas_setup);
> +
> +int meson_canvas_alloc(struct meson_canvas *canvas, u8 *canvas_index)
> +{
> +	int i;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&canvas->lock, flags);
> +	for (i = 0; i < NUM_CANVAS; ++i) {
> +		if (!canvas->used[i]) {
> +			canvas->used[i] = 1;
> +			spin_unlock_irqrestore(&canvas->lock, flags);
> +			*canvas_index = i;
> +			return 0;
> +		}
> +	}
> +	spin_unlock_irqrestore(&canvas->lock, flags);
> +
> +	dev_err(canvas->dev, "No more canvas available\n");
> +	return -ENODEV;
> +}
> +EXPORT_SYMBOL_GPL(meson_canvas_alloc);
> +
> +int meson_canvas_free(struct meson_canvas *canvas, u8 canvas_index)
> +{
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&canvas->lock, flags);
> +	if (!canvas->used[canvas_index]) {
> +		dev_err(canvas->dev,
> +			"Trying to free unused canvas %u\n", canvas_index);
> +		spin_unlock_irqrestore(&canvas->lock, flags);
> +		return -EINVAL;
> +	}
> +	canvas->used[canvas_index] = 0;
> +	spin_unlock_irqrestore(&canvas->lock, flags);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(meson_canvas_free);
> +
> +static int meson_canvas_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct meson_canvas *canvas;
> +
> +	canvas = devm_kzalloc(dev, sizeof(*canvas), GFP_KERNEL);
> +	if (!canvas)
> +		return -ENOMEM;
> +
> +	canvas->regmap_dmc =
> +		syscon_node_to_regmap(of_get_parent(dev->of_node));
> +	if (IS_ERR(canvas->regmap_dmc)) {
> +		dev_err(dev, "failed to get DMC regmap\n");
> +		return PTR_ERR(canvas->regmap_dmc);
> +	}
> +
> +	canvas->dev = dev;
> +	spin_lock_init(&canvas->lock);
> +	dev_set_drvdata(dev, canvas);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id canvas_dt_match[] = {
> +	{ .compatible = "amlogic,canvas" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, canvas_dt_match);
> +
> +static struct platform_driver meson_canvas_driver = {
> +	.probe = meson_canvas_probe,
> +	.driver = {
> +		.name = "amlogic-canvas",
> +		.of_match_table = canvas_dt_match,
> +	},
> +};
> +module_platform_driver(meson_canvas_driver);
> +
> +MODULE_DESCRIPTION("Amlogic Canvas driver");
> +MODULE_AUTHOR("Maxime Jourdan <maxi.jourdan@wanadoo.fr>");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/soc/amlogic/meson-canvas.h b/include/linux/soc/amlogic/meson-canvas.h
> new file mode 100644
> index 000000000000..c164202d8e39
> --- /dev/null
> +++ b/include/linux/soc/amlogic/meson-canvas.h
> @@ -0,0 +1,65 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * Copyright (C) 2018 Maxime Jourdan <maxi.jourdan@wanadoo.fr>
> + */
> +#ifndef MESON_CANVAS_H
> +#define MESON_CANVAS_H
> +
> +#include <linux/kernel.h>
> +
> +#define MESON_CANVAS_WRAP_NONE	0x00
> +#define MESON_CANVAS_WRAP_X	0x01
> +#define MESON_CANVAS_WRAP_Y	0x02
> +
> +#define MESON_CANVAS_BLKMODE_LINEAR	0x00
> +#define MESON_CANVAS_BLKMODE_32x32	0x01
> +#define MESON_CANVAS_BLKMODE_64x64	0x02
> +
> +#define MESON_CANVAS_ENDIAN_SWAP16	0x1
> +#define MESON_CANVAS_ENDIAN_SWAP32	0x3
> +#define MESON_CANVAS_ENDIAN_SWAP64	0x7
> +#define MESON_CANVAS_ENDIAN_SWAP128	0xf
> +
> +struct meson_canvas;
> +
> +/**
> + * meson_canvas_get() - get a canvas provider instance
> + *
> + * @dev: your device

s/your device/consumer device pointer ?

> + */
> +struct meson_canvas *meson_canvas_get(struct device *dev);
> +
> +/**
> + * meson_canvas_alloc() - take ownership of a canvas
> + *
> + * @canvas: canvas provider instance retrieved from meson_canvas_get()
> + * @canvas_index: will be filled with the canvas ID
> + */
> +int meson_canvas_alloc(struct meson_canvas *canvas, u8 *canvas_index);
> +
> +/**
> + * meson_canvas_free() - remove ownership from a canvas
> + *
> + * @canvas: canvas provider instance retrieved from meson_canvas_get()
> + * @canvas_index: canvas ID that was obtained via meson_canvas_alloc()
> + */
> +int meson_canvas_free(struct meson_canvas *canvas, u8 canvas_index);
> +
> +/**
> + * meson_canvas_setup() - configure a canvas
> + *
> + * @canvas: canvas provider instance retrieved from meson_canvas_get()
> + * @canvas_index: canvas ID that was obtained via meson_canvas_alloc()
> + * @addr: physical address to the pixel buffer
> + * @stride: width of the buffer
> + * @height: height of the buffer
> + * @wrap: undocumented
> + * @blkmode: block mode (linear, 32x32, 64x64)
> + * @endian: byte swapping (swap16, swap32, swap64, swap128)
> + */
> +int meson_canvas_setup(struct meson_canvas *canvas, u8 canvas_index,
> +		       u32 addr, u32 stride, u32 height,
> +		       unsigned int wrap, unsigned int blkmode,
> +		       unsigned int endian);
> +
> +#endif
Neil Armstrong Aug. 8, 2018, 3:10 p.m. UTC | #2
On 08/08/2018 09:45, Jerome Brunet wrote:
> On Wed, 2018-08-08 at 00:00 +0200, Maxime Jourdan wrote:
>> Amlogic SoCs have a repository of 256 canvas which they use to
>> describe pixel buffers.
>>
>> They contain metadata like width, height, block mode, endianness [..]
>>
>> Many IPs within those SoCs like vdec/vpu rely on those canvas to read/write
>> pixels.
>>
>> Signed-off-by: Maxime Jourdan <maxi.jourdan@wanadoo.fr>
>> Tested-by: Neil Armstrong <narmstrong@baylibre.com>
> 
> Thanks for making the changes Martin, I do prefer this version. You did not have
> to drop the ops, until it is really needed because of some SoC quirks, I guess
> it is simpler this way
> 
> With some answers to the nitpicks below, feel free to add :
> 
> Reviewed-by: Jerome Brunet <jbrunet@baylibre.com>
> 
>> ---
>>  drivers/soc/amlogic/Kconfig              |   7 +
>>  drivers/soc/amlogic/Makefile             |   1 +
>>  drivers/soc/amlogic/meson-canvas.c       | 185 +++++++++++++++++++++++
>>  include/linux/soc/amlogic/meson-canvas.h |  65 ++++++++
>>  4 files changed, 258 insertions(+)
>>  create mode 100644 drivers/soc/amlogic/meson-canvas.c
>>  create mode 100644 include/linux/soc/amlogic/meson-canvas.h
>>
>> diff --git a/drivers/soc/amlogic/Kconfig b/drivers/soc/amlogic/Kconfig
>> index b04f6e4aedbc..2f282b472912 100644
>> --- a/drivers/soc/amlogic/Kconfig
>> +++ b/drivers/soc/amlogic/Kconfig
>> @@ -1,5 +1,12 @@
>>  menu "Amlogic SoC drivers"
>>  
>> +config MESON_CANVAS
>> +	tristate "Amlogic Meson Canvas driver"
>> +	depends on ARCH_MESON || COMPILE_TEST
>> +	default n
>> +	help
>> +	  Say yes to support the canvas IP for Amlogic SoCs.
>> +
>>  config MESON_GX_SOCINFO
>>  	bool "Amlogic Meson GX SoC Information driver"
>>  	depends on ARCH_MESON || COMPILE_TEST
>> diff --git a/drivers/soc/amlogic/Makefile b/drivers/soc/amlogic/Makefile
>> index 8fa321893928..0ab16d35ac36 100644
>> --- a/drivers/soc/amlogic/Makefile
>> +++ b/drivers/soc/amlogic/Makefile
>> @@ -1,3 +1,4 @@
>> +obj-$(CONFIG_MESON_CANVAS) += meson-canvas.o
>>  obj-$(CONFIG_MESON_GX_SOCINFO) += meson-gx-socinfo.o
>>  obj-$(CONFIG_MESON_GX_PM_DOMAINS) += meson-gx-pwrc-vpu.o
>>  obj-$(CONFIG_MESON_MX_SOCINFO) += meson-mx-socinfo.o
>> diff --git a/drivers/soc/amlogic/meson-canvas.c b/drivers/soc/amlogic/meson-canvas.c
>> new file mode 100644
>> index 000000000000..c461334b36d4
>> --- /dev/null
>> +++ b/drivers/soc/amlogic/meson-canvas.c
>> @@ -0,0 +1,185 @@
>> +// SPDX-License-Identifier: GPL-2.0+
>> +/*
>> + * Copyright (C) 2018 Maxime Jourdan <maxi.jourdan@wanadoo.fr>
>> + * Copyright (C) 2016 BayLibre, SAS
>> + * Author: Neil Armstrong <narmstrong@baylibre.com>
>> + * Copyright (C) 2015 Amlogic, Inc. All rights reserved.
>> + * Copyright (C) 2014 Endless Mobile
>> + */
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/module.h>
>> +#include <linux/regmap.h>
>> +#include <linux/soc/amlogic/meson-canvas.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_platform.h>
>> +#include <linux/io.h>
>> +
>> +#define NUM_CANVAS 256
>> +
>> +/* DMC Registers */
>> +#define DMC_CAV_LUT_DATAL	0x48 /* 0x12 offset in data sheet */
>> +	#define CANVAS_WIDTH_LBIT	29
>> +	#define CANVAS_WIDTH_LWID       3
>> +#define DMC_CAV_LUT_DATAH	0x4c /* 0x13 offset in data sheet */
>> +	#define CANVAS_WIDTH_HBIT       0
>> +	#define CANVAS_HEIGHT_BIT       9
>> +	#define CANVAS_BLKMODE_BIT      24
>> +#define DMC_CAV_LUT_ADDR	0x50 /* 0x14 offset in data sheet */
>> +	#define CANVAS_LUT_WR_EN        (0x2 << 8)
>> +	#define CANVAS_LUT_RD_EN        (0x1 << 8)
>> +
>> +struct meson_canvas {
>> +	struct device *dev;
>> +	struct regmap *regmap_dmc;
>> +	spinlock_t lock; /* canvas device lock */
>> +	u8 used[NUM_CANVAS];
>> +};
>> +
>> +struct meson_canvas *meson_canvas_get(struct device *dev)
>> +{
>> +	struct device_node *canvas_node;
>> +	struct platform_device *canvas_pdev;
>> +	struct meson_canvas *canvas;
>> +
>> +	canvas_node = of_parse_phandle(dev->of_node, "amlogic,canvas", 0);
>> +	if (!canvas_node)
>> +		return ERR_PTR(-ENODEV);
>> +
>> +	canvas_pdev = of_find_device_by_node(canvas_node);
>> +	if (!canvas_pdev) {
>> +		dev_err(dev, "Unable to find canvas pdev\n");
>> +		return ERR_PTR(-ENODEV);
>> +	}

I should be -EPROBE_DEFER here since the canvas driver maybe hasn't probed yet.

>> +
>> +	canvas = dev_get_drvdata(&canvas_pdev->dev);
>> +	if (!canvas)
>> +		return ERR_PTR(-ENODEV);
> 
> You've got your device at this point, maybe EINVAL instead ?

This shouldn't fail here... I'm not sure what should be the error.

> 
>> +
>> +	return canvas;
>> +}
>> +EXPORT_SYMBOL_GPL(meson_canvas_get);
>> +
>> +int meson_canvas_setup(struct meson_canvas *canvas, u8 canvas_index,
>> +		       u32 addr, u32 stride, u32 height,
>> +		       unsigned int wrap,
>> +		       unsigned int blkmode,
>> +		       unsigned int endian)
>> +{
>> +	struct regmap *regmap = canvas->regmap_dmc;
>> +	unsigned long flags;
>> +	u32 val;
>> +
>> +	spin_lock_irqsave(&canvas->lock, flags);
>> +	if (!canvas->used[canvas_index]) {
>> +		dev_err(canvas->dev,
>> +			"Trying to setup non allocated canvas %u\n",
>> +			canvas_index);
>> +		spin_unlock_irqrestore(&canvas->lock, flags);
>> +		return -EINVAL;
>> +	}
>> +
>> +	regmap_write(regmap, DMC_CAV_LUT_DATAL,
>> +		     ((addr + 7) >> 3) |
>> +		     (((stride + 7) >> 3) << CANVAS_WIDTH_LBIT));
>> +
>> +	regmap_write(regmap, DMC_CAV_LUT_DATAH,
>> +		     ((((stride + 7) >> 3) >> CANVAS_WIDTH_LWID) <<
>> +						CANVAS_WIDTH_HBIT) |
>> +		     (height << CANVAS_HEIGHT_BIT) |
>> +		     (wrap << 22) |
>> +		     (blkmode << CANVAS_BLKMODE_BIT) |
>> +		     (endian << 26));
>> +
>> +	regmap_write(regmap, DMC_CAV_LUT_ADDR,
>> +		     CANVAS_LUT_WR_EN | canvas_index);
>> +
>> +	/* Force a read-back to make sure everything is flushed. */
>> +	regmap_read(regmap, DMC_CAV_LUT_DATAH, &val);
> 
> I suppose this something you got from the vendor kernel ? Out of curiosity, have
> you tried w/o it ? I am wondering if this is really necessary ? 


It's explicit in the Amlogic source, you need a readback to make sure it's taken in account.

> 
> 
>> +	spin_unlock_irqrestore(&canvas->lock, flags);
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(meson_canvas_setup);
>> +
>> +int meson_canvas_alloc(struct meson_canvas *canvas, u8 *canvas_index)
>> +{
>> +	int i;
>> +	unsigned long flags;
>> +
>> +	spin_lock_irqsave(&canvas->lock, flags);
>> +	for (i = 0; i < NUM_CANVAS; ++i) {
>> +		if (!canvas->used[i]) {
>> +			canvas->used[i] = 1;
>> +			spin_unlock_irqrestore(&canvas->lock, flags);
>> +			*canvas_index = i;
>> +			return 0;
>> +		}
>> +	}
>> +	spin_unlock_irqrestore(&canvas->lock, flags);
>> +
>> +	dev_err(canvas->dev, "No more canvas available\n");
>> +	return -ENODEV;
>> +}
>> +EXPORT_SYMBOL_GPL(meson_canvas_alloc);
>> +
>> +int meson_canvas_free(struct meson_canvas *canvas, u8 canvas_index)
>> +{
>> +	unsigned long flags;
>> +
>> +	spin_lock_irqsave(&canvas->lock, flags);
>> +	if (!canvas->used[canvas_index]) {
>> +		dev_err(canvas->dev,
>> +			"Trying to free unused canvas %u\n", canvas_index);
>> +		spin_unlock_irqrestore(&canvas->lock, flags);
>> +		return -EINVAL;
>> +	}
>> +	canvas->used[canvas_index] = 0;
>> +	spin_unlock_irqrestore(&canvas->lock, flags);
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(meson_canvas_free);
>> +
>> +static int meson_canvas_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	struct meson_canvas *canvas;
>> +
>> +	canvas = devm_kzalloc(dev, sizeof(*canvas), GFP_KERNEL);
>> +	if (!canvas)
>> +		return -ENOMEM;
>> +
>> +	canvas->regmap_dmc =
>> +		syscon_node_to_regmap(of_get_parent(dev->of_node));
>> +	if (IS_ERR(canvas->regmap_dmc)) {
>> +		dev_err(dev, "failed to get DMC regmap\n");
>> +		return PTR_ERR(canvas->regmap_dmc);
>> +	}
>> +
>> +	canvas->dev = dev;
>> +	spin_lock_init(&canvas->lock);
>> +	dev_set_drvdata(dev, canvas);
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct of_device_id canvas_dt_match[] = {
>> +	{ .compatible = "amlogic,canvas" },
>> +	{}
>> +};
>> +MODULE_DEVICE_TABLE(of, canvas_dt_match);
>> +
>> +static struct platform_driver meson_canvas_driver = {
>> +	.probe = meson_canvas_probe,
>> +	.driver = {
>> +		.name = "amlogic-canvas",
>> +		.of_match_table = canvas_dt_match,
>> +	},
>> +};
>> +module_platform_driver(meson_canvas_driver);
>> +
>> +MODULE_DESCRIPTION("Amlogic Canvas driver");
>> +MODULE_AUTHOR("Maxime Jourdan <maxi.jourdan@wanadoo.fr>");
>> +MODULE_LICENSE("GPL");
>> diff --git a/include/linux/soc/amlogic/meson-canvas.h b/include/linux/soc/amlogic/meson-canvas.h
>> new file mode 100644
>> index 000000000000..c164202d8e39
>> --- /dev/null
>> +++ b/include/linux/soc/amlogic/meson-canvas.h
>> @@ -0,0 +1,65 @@
>> +/* SPDX-License-Identifier: GPL-2.0+ */
>> +/*
>> + * Copyright (C) 2018 Maxime Jourdan <maxi.jourdan@wanadoo.fr>
>> + */
>> +#ifndef MESON_CANVAS_H
>> +#define MESON_CANVAS_H
>> +
>> +#include <linux/kernel.h>
>> +
>> +#define MESON_CANVAS_WRAP_NONE	0x00
>> +#define MESON_CANVAS_WRAP_X	0x01
>> +#define MESON_CANVAS_WRAP_Y	0x02
>> +
>> +#define MESON_CANVAS_BLKMODE_LINEAR	0x00
>> +#define MESON_CANVAS_BLKMODE_32x32	0x01
>> +#define MESON_CANVAS_BLKMODE_64x64	0x02
>> +
>> +#define MESON_CANVAS_ENDIAN_SWAP16	0x1
>> +#define MESON_CANVAS_ENDIAN_SWAP32	0x3
>> +#define MESON_CANVAS_ENDIAN_SWAP64	0x7
>> +#define MESON_CANVAS_ENDIAN_SWAP128	0xf
>> +
>> +struct meson_canvas;
>> +
>> +/**
>> + * meson_canvas_get() - get a canvas provider instance
>> + *
>> + * @dev: your device
> 
> s/your device/consumer device pointer ?
> 
>> + */
>> +struct meson_canvas *meson_canvas_get(struct device *dev);
>> +
>> +/**
>> + * meson_canvas_alloc() - take ownership of a canvas
>> + *
>> + * @canvas: canvas provider instance retrieved from meson_canvas_get()
>> + * @canvas_index: will be filled with the canvas ID
>> + */
>> +int meson_canvas_alloc(struct meson_canvas *canvas, u8 *canvas_index);
>> +
>> +/**
>> + * meson_canvas_free() - remove ownership from a canvas
>> + *
>> + * @canvas: canvas provider instance retrieved from meson_canvas_get()
>> + * @canvas_index: canvas ID that was obtained via meson_canvas_alloc()
>> + */
>> +int meson_canvas_free(struct meson_canvas *canvas, u8 canvas_index);
>> +
>> +/**
>> + * meson_canvas_setup() - configure a canvas
>> + *
>> + * @canvas: canvas provider instance retrieved from meson_canvas_get()
>> + * @canvas_index: canvas ID that was obtained via meson_canvas_alloc()
>> + * @addr: physical address to the pixel buffer
>> + * @stride: width of the buffer
>> + * @height: height of the buffer
>> + * @wrap: undocumented
>> + * @blkmode: block mode (linear, 32x32, 64x64)
>> + * @endian: byte swapping (swap16, swap32, swap64, swap128)
>> + */
>> +int meson_canvas_setup(struct meson_canvas *canvas, u8 canvas_index,
>> +		       u32 addr, u32 stride, u32 height,
>> +		       unsigned int wrap, unsigned int blkmode,
>> +		       unsigned int endian);
>> +
>> +#endif
> 
>
Maxime Jourdan Aug. 10, 2018, 6:40 a.m. UTC | #3
2018-08-08 17:10 GMT+02:00 Neil Armstrong <narmstrong@baylibre.com>:
> On 08/08/2018 09:45, Jerome Brunet wrote:
>> On Wed, 2018-08-08 at 00:00 +0200, Maxime Jourdan wrote:
>>> Amlogic SoCs have a repository of 256 canvas which they use to
>>> describe pixel buffers.
>>>
>>> They contain metadata like width, height, block mode, endianness [..]
>>>
>>> Many IPs within those SoCs like vdec/vpu rely on those canvas to read/write
>>> pixels.
>>>
>>> Signed-off-by: Maxime Jourdan <maxi.jourdan@wanadoo.fr>
>>> Tested-by: Neil Armstrong <narmstrong@baylibre.com>
>>
>> Thanks for making the changes Martin, I do prefer this version. You did not have
>> to drop the ops, until it is really needed because of some SoC quirks, I guess
>> it is simpler this way
>>
>> With some answers to the nitpicks below, feel free to add :
>>
>> Reviewed-by: Jerome Brunet <jbrunet@baylibre.com>
>>
>>> ---
>>>  drivers/soc/amlogic/Kconfig              |   7 +
>>>  drivers/soc/amlogic/Makefile             |   1 +
>>>  drivers/soc/amlogic/meson-canvas.c       | 185 +++++++++++++++++++++++
>>>  include/linux/soc/amlogic/meson-canvas.h |  65 ++++++++
>>>  4 files changed, 258 insertions(+)
>>>  create mode 100644 drivers/soc/amlogic/meson-canvas.c
>>>  create mode 100644 include/linux/soc/amlogic/meson-canvas.h
>>>
>>> diff --git a/drivers/soc/amlogic/Kconfig b/drivers/soc/amlogic/Kconfig
>>> index b04f6e4aedbc..2f282b472912 100644
>>> --- a/drivers/soc/amlogic/Kconfig
>>> +++ b/drivers/soc/amlogic/Kconfig
>>> @@ -1,5 +1,12 @@
>>>  menu "Amlogic SoC drivers"
>>>
>>> +config MESON_CANVAS
>>> +    tristate "Amlogic Meson Canvas driver"
>>> +    depends on ARCH_MESON || COMPILE_TEST
>>> +    default n
>>> +    help
>>> +      Say yes to support the canvas IP for Amlogic SoCs.
>>> +
>>>  config MESON_GX_SOCINFO
>>>      bool "Amlogic Meson GX SoC Information driver"
>>>      depends on ARCH_MESON || COMPILE_TEST
>>> diff --git a/drivers/soc/amlogic/Makefile b/drivers/soc/amlogic/Makefile
>>> index 8fa321893928..0ab16d35ac36 100644
>>> --- a/drivers/soc/amlogic/Makefile
>>> +++ b/drivers/soc/amlogic/Makefile
>>> @@ -1,3 +1,4 @@
>>> +obj-$(CONFIG_MESON_CANVAS) += meson-canvas.o
>>>  obj-$(CONFIG_MESON_GX_SOCINFO) += meson-gx-socinfo.o
>>>  obj-$(CONFIG_MESON_GX_PM_DOMAINS) += meson-gx-pwrc-vpu.o
>>>  obj-$(CONFIG_MESON_MX_SOCINFO) += meson-mx-socinfo.o
>>> diff --git a/drivers/soc/amlogic/meson-canvas.c b/drivers/soc/amlogic/meson-canvas.c
>>> new file mode 100644
>>> index 000000000000..c461334b36d4
>>> --- /dev/null
>>> +++ b/drivers/soc/amlogic/meson-canvas.c
>>> @@ -0,0 +1,185 @@
>>> +// SPDX-License-Identifier: GPL-2.0+
>>> +/*
>>> + * Copyright (C) 2018 Maxime Jourdan <maxi.jourdan@wanadoo.fr>
>>> + * Copyright (C) 2016 BayLibre, SAS
>>> + * Author: Neil Armstrong <narmstrong@baylibre.com>
>>> + * Copyright (C) 2015 Amlogic, Inc. All rights reserved.
>>> + * Copyright (C) 2014 Endless Mobile
>>> + */
>>> +
>>> +#include <linux/kernel.h>
>>> +#include <linux/mfd/syscon.h>
>>> +#include <linux/module.h>
>>> +#include <linux/regmap.h>
>>> +#include <linux/soc/amlogic/meson-canvas.h>
>>> +#include <linux/of_address.h>
>>> +#include <linux/of_platform.h>
>>> +#include <linux/io.h>
>>> +
>>> +#define NUM_CANVAS 256
>>> +
>>> +/* DMC Registers */
>>> +#define DMC_CAV_LUT_DATAL   0x48 /* 0x12 offset in data sheet */
>>> +    #define CANVAS_WIDTH_LBIT       29
>>> +    #define CANVAS_WIDTH_LWID       3
>>> +#define DMC_CAV_LUT_DATAH   0x4c /* 0x13 offset in data sheet */
>>> +    #define CANVAS_WIDTH_HBIT       0
>>> +    #define CANVAS_HEIGHT_BIT       9
>>> +    #define CANVAS_BLKMODE_BIT      24
>>> +#define DMC_CAV_LUT_ADDR    0x50 /* 0x14 offset in data sheet */
>>> +    #define CANVAS_LUT_WR_EN        (0x2 << 8)
>>> +    #define CANVAS_LUT_RD_EN        (0x1 << 8)
>>> +
>>> +struct meson_canvas {
>>> +    struct device *dev;
>>> +    struct regmap *regmap_dmc;
>>> +    spinlock_t lock; /* canvas device lock */
>>> +    u8 used[NUM_CANVAS];
>>> +};
>>> +
>>> +struct meson_canvas *meson_canvas_get(struct device *dev)
>>> +{
>>> +    struct device_node *canvas_node;
>>> +    struct platform_device *canvas_pdev;
>>> +    struct meson_canvas *canvas;
>>> +
>>> +    canvas_node = of_parse_phandle(dev->of_node, "amlogic,canvas", 0);
>>> +    if (!canvas_node)
>>> +            return ERR_PTR(-ENODEV);
>>> +
>>> +    canvas_pdev = of_find_device_by_node(canvas_node);
>>> +    if (!canvas_pdev) {
>>> +            dev_err(dev, "Unable to find canvas pdev\n");
>>> +            return ERR_PTR(-ENODEV);
>>> +    }
>
> I should be -EPROBE_DEFER here since the canvas driver maybe hasn't probed yet.

Ack.

>>> +
>>> +    canvas = dev_get_drvdata(&canvas_pdev->dev);
>>> +    if (!canvas)
>>> +            return ERR_PTR(-ENODEV);
>>
>> You've got your device at this point, maybe EINVAL instead ?
>
> This shouldn't fail here... I'm not sure what should be the error.

I wasn't sure if it was possible to retrieve the pdev with a failed probe.

Should I just assume canvas will never be NULL here then ?

>>
>>> +
>>> +    return canvas;
>>> +}
>>> +EXPORT_SYMBOL_GPL(meson_canvas_get);
>>> +
>>> +int meson_canvas_setup(struct meson_canvas *canvas, u8 canvas_index,
>>> +                   u32 addr, u32 stride, u32 height,
>>> +                   unsigned int wrap,
>>> +                   unsigned int blkmode,
>>> +                   unsigned int endian)
>>> +{
>>> +    struct regmap *regmap = canvas->regmap_dmc;
>>> +    unsigned long flags;
>>> +    u32 val;
>>> +
>>> +    spin_lock_irqsave(&canvas->lock, flags);
>>> +    if (!canvas->used[canvas_index]) {
>>> +            dev_err(canvas->dev,
>>> +                    "Trying to setup non allocated canvas %u\n",
>>> +                    canvas_index);
>>> +            spin_unlock_irqrestore(&canvas->lock, flags);
>>> +            return -EINVAL;
>>> +    }
>>> +
>>> +    regmap_write(regmap, DMC_CAV_LUT_DATAL,
>>> +                 ((addr + 7) >> 3) |
>>> +                 (((stride + 7) >> 3) << CANVAS_WIDTH_LBIT));
>>> +
>>> +    regmap_write(regmap, DMC_CAV_LUT_DATAH,
>>> +                 ((((stride + 7) >> 3) >> CANVAS_WIDTH_LWID) <<
>>> +                                            CANVAS_WIDTH_HBIT) |
>>> +                 (height << CANVAS_HEIGHT_BIT) |
>>> +                 (wrap << 22) |
>>> +                 (blkmode << CANVAS_BLKMODE_BIT) |
>>> +                 (endian << 26));
>>> +
>>> +    regmap_write(regmap, DMC_CAV_LUT_ADDR,
>>> +                 CANVAS_LUT_WR_EN | canvas_index);
>>> +
>>> +    /* Force a read-back to make sure everything is flushed. */
>>> +    regmap_read(regmap, DMC_CAV_LUT_DATAH, &val);
>>
>> I suppose this something you got from the vendor kernel ? Out of curiosity, have
>> you tried w/o it ? I am wondering if this is really necessary ?
>
>
> It's explicit in the Amlogic source, you need a readback to make sure it's taken in account.
>
>>
>>
>>> +    spin_unlock_irqrestore(&canvas->lock, flags);
>>> +
>>> +    return 0;
>>> +}
>>> +EXPORT_SYMBOL_GPL(meson_canvas_setup);
>>> +
>>> +int meson_canvas_alloc(struct meson_canvas *canvas, u8 *canvas_index)
>>> +{
>>> +    int i;
>>> +    unsigned long flags;
>>> +
>>> +    spin_lock_irqsave(&canvas->lock, flags);
>>> +    for (i = 0; i < NUM_CANVAS; ++i) {
>>> +            if (!canvas->used[i]) {
>>> +                    canvas->used[i] = 1;
>>> +                    spin_unlock_irqrestore(&canvas->lock, flags);
>>> +                    *canvas_index = i;
>>> +                    return 0;
>>> +            }
>>> +    }
>>> +    spin_unlock_irqrestore(&canvas->lock, flags);
>>> +
>>> +    dev_err(canvas->dev, "No more canvas available\n");
>>> +    return -ENODEV;
>>> +}
>>> +EXPORT_SYMBOL_GPL(meson_canvas_alloc);
>>> +
>>> +int meson_canvas_free(struct meson_canvas *canvas, u8 canvas_index)
>>> +{
>>> +    unsigned long flags;
>>> +
>>> +    spin_lock_irqsave(&canvas->lock, flags);
>>> +    if (!canvas->used[canvas_index]) {
>>> +            dev_err(canvas->dev,
>>> +                    "Trying to free unused canvas %u\n", canvas_index);
>>> +            spin_unlock_irqrestore(&canvas->lock, flags);
>>> +            return -EINVAL;
>>> +    }
>>> +    canvas->used[canvas_index] = 0;
>>> +    spin_unlock_irqrestore(&canvas->lock, flags);
>>> +
>>> +    return 0;
>>> +}
>>> +EXPORT_SYMBOL_GPL(meson_canvas_free);
>>> +
>>> +static int meson_canvas_probe(struct platform_device *pdev)
>>> +{
>>> +    struct device *dev = &pdev->dev;
>>> +    struct meson_canvas *canvas;
>>> +
>>> +    canvas = devm_kzalloc(dev, sizeof(*canvas), GFP_KERNEL);
>>> +    if (!canvas)
>>> +            return -ENOMEM;
>>> +
>>> +    canvas->regmap_dmc =
>>> +            syscon_node_to_regmap(of_get_parent(dev->of_node));
>>> +    if (IS_ERR(canvas->regmap_dmc)) {
>>> +            dev_err(dev, "failed to get DMC regmap\n");
>>> +            return PTR_ERR(canvas->regmap_dmc);
>>> +    }
>>> +
>>> +    canvas->dev = dev;
>>> +    spin_lock_init(&canvas->lock);
>>> +    dev_set_drvdata(dev, canvas);
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static const struct of_device_id canvas_dt_match[] = {
>>> +    { .compatible = "amlogic,canvas" },
>>> +    {}
>>> +};
>>> +MODULE_DEVICE_TABLE(of, canvas_dt_match);
>>> +
>>> +static struct platform_driver meson_canvas_driver = {
>>> +    .probe = meson_canvas_probe,
>>> +    .driver = {
>>> +            .name = "amlogic-canvas",
>>> +            .of_match_table = canvas_dt_match,
>>> +    },
>>> +};
>>> +module_platform_driver(meson_canvas_driver);
>>> +
>>> +MODULE_DESCRIPTION("Amlogic Canvas driver");
>>> +MODULE_AUTHOR("Maxime Jourdan <maxi.jourdan@wanadoo.fr>");
>>> +MODULE_LICENSE("GPL");
>>> diff --git a/include/linux/soc/amlogic/meson-canvas.h b/include/linux/soc/amlogic/meson-canvas.h
>>> new file mode 100644
>>> index 000000000000..c164202d8e39
>>> --- /dev/null
>>> +++ b/include/linux/soc/amlogic/meson-canvas.h
>>> @@ -0,0 +1,65 @@
>>> +/* SPDX-License-Identifier: GPL-2.0+ */
>>> +/*
>>> + * Copyright (C) 2018 Maxime Jourdan <maxi.jourdan@wanadoo.fr>
>>> + */
>>> +#ifndef MESON_CANVAS_H
>>> +#define MESON_CANVAS_H
>>> +
>>> +#include <linux/kernel.h>
>>> +
>>> +#define MESON_CANVAS_WRAP_NONE      0x00
>>> +#define MESON_CANVAS_WRAP_X 0x01
>>> +#define MESON_CANVAS_WRAP_Y 0x02
>>> +
>>> +#define MESON_CANVAS_BLKMODE_LINEAR 0x00
>>> +#define MESON_CANVAS_BLKMODE_32x32  0x01
>>> +#define MESON_CANVAS_BLKMODE_64x64  0x02
>>> +
>>> +#define MESON_CANVAS_ENDIAN_SWAP16  0x1
>>> +#define MESON_CANVAS_ENDIAN_SWAP32  0x3
>>> +#define MESON_CANVAS_ENDIAN_SWAP64  0x7
>>> +#define MESON_CANVAS_ENDIAN_SWAP128 0xf
>>> +
>>> +struct meson_canvas;
>>> +
>>> +/**
>>> + * meson_canvas_get() - get a canvas provider instance
>>> + *
>>> + * @dev: your device
>>
>> s/your device/consumer device pointer ?
>>

Ack.

>>> + */
>>> +struct meson_canvas *meson_canvas_get(struct device *dev);
>>> +
>>> +/**
>>> + * meson_canvas_alloc() - take ownership of a canvas
>>> + *
>>> + * @canvas: canvas provider instance retrieved from meson_canvas_get()
>>> + * @canvas_index: will be filled with the canvas ID
>>> + */
>>> +int meson_canvas_alloc(struct meson_canvas *canvas, u8 *canvas_index);
>>> +
>>> +/**
>>> + * meson_canvas_free() - remove ownership from a canvas
>>> + *
>>> + * @canvas: canvas provider instance retrieved from meson_canvas_get()
>>> + * @canvas_index: canvas ID that was obtained via meson_canvas_alloc()
>>> + */
>>> +int meson_canvas_free(struct meson_canvas *canvas, u8 canvas_index);
>>> +
>>> +/**
>>> + * meson_canvas_setup() - configure a canvas
>>> + *
>>> + * @canvas: canvas provider instance retrieved from meson_canvas_get()
>>> + * @canvas_index: canvas ID that was obtained via meson_canvas_alloc()
>>> + * @addr: physical address to the pixel buffer
>>> + * @stride: width of the buffer
>>> + * @height: height of the buffer
>>> + * @wrap: undocumented
>>> + * @blkmode: block mode (linear, 32x32, 64x64)
>>> + * @endian: byte swapping (swap16, swap32, swap64, swap128)
>>> + */
>>> +int meson_canvas_setup(struct meson_canvas *canvas, u8 canvas_index,
>>> +                   u32 addr, u32 stride, u32 height,
>>> +                   unsigned int wrap, unsigned int blkmode,
>>> +                   unsigned int endian);
>>> +
>>> +#endif
>>
>>
>
>
> _______________________________________________
> linux-amlogic mailing list
> linux-amlogic@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-amlogic

Maxime
diff mbox series

Patch

diff --git a/drivers/soc/amlogic/Kconfig b/drivers/soc/amlogic/Kconfig
index b04f6e4aedbc..2f282b472912 100644
--- a/drivers/soc/amlogic/Kconfig
+++ b/drivers/soc/amlogic/Kconfig
@@ -1,5 +1,12 @@ 
 menu "Amlogic SoC drivers"
 
+config MESON_CANVAS
+	tristate "Amlogic Meson Canvas driver"
+	depends on ARCH_MESON || COMPILE_TEST
+	default n
+	help
+	  Say yes to support the canvas IP for Amlogic SoCs.
+
 config MESON_GX_SOCINFO
 	bool "Amlogic Meson GX SoC Information driver"
 	depends on ARCH_MESON || COMPILE_TEST
diff --git a/drivers/soc/amlogic/Makefile b/drivers/soc/amlogic/Makefile
index 8fa321893928..0ab16d35ac36 100644
--- a/drivers/soc/amlogic/Makefile
+++ b/drivers/soc/amlogic/Makefile
@@ -1,3 +1,4 @@ 
+obj-$(CONFIG_MESON_CANVAS) += meson-canvas.o
 obj-$(CONFIG_MESON_GX_SOCINFO) += meson-gx-socinfo.o
 obj-$(CONFIG_MESON_GX_PM_DOMAINS) += meson-gx-pwrc-vpu.o
 obj-$(CONFIG_MESON_MX_SOCINFO) += meson-mx-socinfo.o
diff --git a/drivers/soc/amlogic/meson-canvas.c b/drivers/soc/amlogic/meson-canvas.c
new file mode 100644
index 000000000000..c461334b36d4
--- /dev/null
+++ b/drivers/soc/amlogic/meson-canvas.c
@@ -0,0 +1,185 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018 Maxime Jourdan <maxi.jourdan@wanadoo.fr>
+ * Copyright (C) 2016 BayLibre, SAS
+ * Author: Neil Armstrong <narmstrong@baylibre.com>
+ * Copyright (C) 2015 Amlogic, Inc. All rights reserved.
+ * Copyright (C) 2014 Endless Mobile
+ */
+
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/soc/amlogic/meson-canvas.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/io.h>
+
+#define NUM_CANVAS 256
+
+/* DMC Registers */
+#define DMC_CAV_LUT_DATAL	0x48 /* 0x12 offset in data sheet */
+	#define CANVAS_WIDTH_LBIT	29
+	#define CANVAS_WIDTH_LWID       3
+#define DMC_CAV_LUT_DATAH	0x4c /* 0x13 offset in data sheet */
+	#define CANVAS_WIDTH_HBIT       0
+	#define CANVAS_HEIGHT_BIT       9
+	#define CANVAS_BLKMODE_BIT      24
+#define DMC_CAV_LUT_ADDR	0x50 /* 0x14 offset in data sheet */
+	#define CANVAS_LUT_WR_EN        (0x2 << 8)
+	#define CANVAS_LUT_RD_EN        (0x1 << 8)
+
+struct meson_canvas {
+	struct device *dev;
+	struct regmap *regmap_dmc;
+	spinlock_t lock; /* canvas device lock */
+	u8 used[NUM_CANVAS];
+};
+
+struct meson_canvas *meson_canvas_get(struct device *dev)
+{
+	struct device_node *canvas_node;
+	struct platform_device *canvas_pdev;
+	struct meson_canvas *canvas;
+
+	canvas_node = of_parse_phandle(dev->of_node, "amlogic,canvas", 0);
+	if (!canvas_node)
+		return ERR_PTR(-ENODEV);
+
+	canvas_pdev = of_find_device_by_node(canvas_node);
+	if (!canvas_pdev) {
+		dev_err(dev, "Unable to find canvas pdev\n");
+		return ERR_PTR(-ENODEV);
+	}
+
+	canvas = dev_get_drvdata(&canvas_pdev->dev);
+	if (!canvas)
+		return ERR_PTR(-ENODEV);
+
+	return canvas;
+}
+EXPORT_SYMBOL_GPL(meson_canvas_get);
+
+int meson_canvas_setup(struct meson_canvas *canvas, u8 canvas_index,
+		       u32 addr, u32 stride, u32 height,
+		       unsigned int wrap,
+		       unsigned int blkmode,
+		       unsigned int endian)
+{
+	struct regmap *regmap = canvas->regmap_dmc;
+	unsigned long flags;
+	u32 val;
+
+	spin_lock_irqsave(&canvas->lock, flags);
+	if (!canvas->used[canvas_index]) {
+		dev_err(canvas->dev,
+			"Trying to setup non allocated canvas %u\n",
+			canvas_index);
+		spin_unlock_irqrestore(&canvas->lock, flags);
+		return -EINVAL;
+	}
+
+	regmap_write(regmap, DMC_CAV_LUT_DATAL,
+		     ((addr + 7) >> 3) |
+		     (((stride + 7) >> 3) << CANVAS_WIDTH_LBIT));
+
+	regmap_write(regmap, DMC_CAV_LUT_DATAH,
+		     ((((stride + 7) >> 3) >> CANVAS_WIDTH_LWID) <<
+						CANVAS_WIDTH_HBIT) |
+		     (height << CANVAS_HEIGHT_BIT) |
+		     (wrap << 22) |
+		     (blkmode << CANVAS_BLKMODE_BIT) |
+		     (endian << 26));
+
+	regmap_write(regmap, DMC_CAV_LUT_ADDR,
+		     CANVAS_LUT_WR_EN | canvas_index);
+
+	/* Force a read-back to make sure everything is flushed. */
+	regmap_read(regmap, DMC_CAV_LUT_DATAH, &val);
+	spin_unlock_irqrestore(&canvas->lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(meson_canvas_setup);
+
+int meson_canvas_alloc(struct meson_canvas *canvas, u8 *canvas_index)
+{
+	int i;
+	unsigned long flags;
+
+	spin_lock_irqsave(&canvas->lock, flags);
+	for (i = 0; i < NUM_CANVAS; ++i) {
+		if (!canvas->used[i]) {
+			canvas->used[i] = 1;
+			spin_unlock_irqrestore(&canvas->lock, flags);
+			*canvas_index = i;
+			return 0;
+		}
+	}
+	spin_unlock_irqrestore(&canvas->lock, flags);
+
+	dev_err(canvas->dev, "No more canvas available\n");
+	return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(meson_canvas_alloc);
+
+int meson_canvas_free(struct meson_canvas *canvas, u8 canvas_index)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&canvas->lock, flags);
+	if (!canvas->used[canvas_index]) {
+		dev_err(canvas->dev,
+			"Trying to free unused canvas %u\n", canvas_index);
+		spin_unlock_irqrestore(&canvas->lock, flags);
+		return -EINVAL;
+	}
+	canvas->used[canvas_index] = 0;
+	spin_unlock_irqrestore(&canvas->lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(meson_canvas_free);
+
+static int meson_canvas_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct meson_canvas *canvas;
+
+	canvas = devm_kzalloc(dev, sizeof(*canvas), GFP_KERNEL);
+	if (!canvas)
+		return -ENOMEM;
+
+	canvas->regmap_dmc =
+		syscon_node_to_regmap(of_get_parent(dev->of_node));
+	if (IS_ERR(canvas->regmap_dmc)) {
+		dev_err(dev, "failed to get DMC regmap\n");
+		return PTR_ERR(canvas->regmap_dmc);
+	}
+
+	canvas->dev = dev;
+	spin_lock_init(&canvas->lock);
+	dev_set_drvdata(dev, canvas);
+
+	return 0;
+}
+
+static const struct of_device_id canvas_dt_match[] = {
+	{ .compatible = "amlogic,canvas" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, canvas_dt_match);
+
+static struct platform_driver meson_canvas_driver = {
+	.probe = meson_canvas_probe,
+	.driver = {
+		.name = "amlogic-canvas",
+		.of_match_table = canvas_dt_match,
+	},
+};
+module_platform_driver(meson_canvas_driver);
+
+MODULE_DESCRIPTION("Amlogic Canvas driver");
+MODULE_AUTHOR("Maxime Jourdan <maxi.jourdan@wanadoo.fr>");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/soc/amlogic/meson-canvas.h b/include/linux/soc/amlogic/meson-canvas.h
new file mode 100644
index 000000000000..c164202d8e39
--- /dev/null
+++ b/include/linux/soc/amlogic/meson-canvas.h
@@ -0,0 +1,65 @@ 
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2018 Maxime Jourdan <maxi.jourdan@wanadoo.fr>
+ */
+#ifndef MESON_CANVAS_H
+#define MESON_CANVAS_H
+
+#include <linux/kernel.h>
+
+#define MESON_CANVAS_WRAP_NONE	0x00
+#define MESON_CANVAS_WRAP_X	0x01
+#define MESON_CANVAS_WRAP_Y	0x02
+
+#define MESON_CANVAS_BLKMODE_LINEAR	0x00
+#define MESON_CANVAS_BLKMODE_32x32	0x01
+#define MESON_CANVAS_BLKMODE_64x64	0x02
+
+#define MESON_CANVAS_ENDIAN_SWAP16	0x1
+#define MESON_CANVAS_ENDIAN_SWAP32	0x3
+#define MESON_CANVAS_ENDIAN_SWAP64	0x7
+#define MESON_CANVAS_ENDIAN_SWAP128	0xf
+
+struct meson_canvas;
+
+/**
+ * meson_canvas_get() - get a canvas provider instance
+ *
+ * @dev: your device
+ */
+struct meson_canvas *meson_canvas_get(struct device *dev);
+
+/**
+ * meson_canvas_alloc() - take ownership of a canvas
+ *
+ * @canvas: canvas provider instance retrieved from meson_canvas_get()
+ * @canvas_index: will be filled with the canvas ID
+ */
+int meson_canvas_alloc(struct meson_canvas *canvas, u8 *canvas_index);
+
+/**
+ * meson_canvas_free() - remove ownership from a canvas
+ *
+ * @canvas: canvas provider instance retrieved from meson_canvas_get()
+ * @canvas_index: canvas ID that was obtained via meson_canvas_alloc()
+ */
+int meson_canvas_free(struct meson_canvas *canvas, u8 canvas_index);
+
+/**
+ * meson_canvas_setup() - configure a canvas
+ *
+ * @canvas: canvas provider instance retrieved from meson_canvas_get()
+ * @canvas_index: canvas ID that was obtained via meson_canvas_alloc()
+ * @addr: physical address to the pixel buffer
+ * @stride: width of the buffer
+ * @height: height of the buffer
+ * @wrap: undocumented
+ * @blkmode: block mode (linear, 32x32, 64x64)
+ * @endian: byte swapping (swap16, swap32, swap64, swap128)
+ */
+int meson_canvas_setup(struct meson_canvas *canvas, u8 canvas_index,
+		       u32 addr, u32 stride, u32 height,
+		       unsigned int wrap, unsigned int blkmode,
+		       unsigned int endian);
+
+#endif