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

[Jerome Brunet <jbrunet@baylibre.com>]

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