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From:   Maxime Jourdan <maxi.jourdan@wanadoo.fr>
Date:   Fri, 10 Aug 2018 08:40:03 +0200
Message-ID: <CAHStOZ4S+dDX73OzGBeND5WUFBNmyhzkQPBsvoVyhqyundBynA@mail.gmail.com>
Subject: Re: [PATCH v2 1/4] soc: amlogic: add meson-canvas driver
To:     Neil Armstrong <narmstrong@baylibre.com>,
        Jerome Brunet <jbrunet@baylibre.com>
Cc:     Maxime Jourdan <maxi.jourdan@wanadoo.fr>,
        Kevin Hilman <khilman@baylibre.com>,
        linux-amlogic <linux-amlogic@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-arm-kernel@lists.infradead.org
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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
>>
>>
>
>
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Maxime