Re: [PATCH 094/120] MIPS: PS2: FB: Frame buffer driver for the PlayStation 2

[Jiaxun Yang <jiaxun.yang@flygoat.com>]

在 2019/9/2 0:26, Fredrik Noring 写道:
> The main limitation is the lack of mmap, since the Graphics Synthesizer
> has local frame buffer memory that is not directly accessible from the
> main bus. The GS has 4 MiB of local memory.
>
> The console drawing primitives are synchronous to allow printk at any
> time. This is highly useful for debugging but it is not the fastest
> possible implementation. The console is nevertheless very fast and
> makes use of several hardware accelerated features of the Graphics
> Synthesizer.
>
> The maximum practical resolution is 1920x1080p at 16 bits per pixel that
> requires 4147200 bytes of local memory, leaving 47104 bytes for a tiled
> font, which at 8x8 pixels and a minimum 4 bits indexed texture palette is
> at most 1464 characters. The indexed palette makes switching colours easy.
> &struct fb_tile_ops is accelerated with GS texture sprites that are fast
> (GS local copy) for the kernel via simple DMA GS commands via the GIF.
>
> Signed-off-by: Fredrik Noring <noring@nocrew.org>

Hi Fredik,

According to kernel policy[1] no more new FBDev driver would be accepted.

Please refactor it to DRM.

Thanks.

[1] http://lkml.iu.edu/hypermail/linux/kernel/1509.3/00253.html

--

Jiaxun Yang

> ---
>   drivers/video/fbdev/Kconfig    |  12 +
>   drivers/video/fbdev/Makefile   |   1 +
>   drivers/video/fbdev/ps2fb.c    | 533 +++++++++++++++++++++++++++++++++
>   include/linux/console_struct.h |   2 +
>   include/uapi/linux/fb.h        |   1 +
>   5 files changed, 549 insertions(+)
>   create mode 100644 drivers/video/fbdev/ps2fb.c
>
> diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig
> index 6b2de93bd302..cc93cbd67b01 100644
> --- a/drivers/video/fbdev/Kconfig
> +++ b/drivers/video/fbdev/Kconfig
> @@ -1999,6 +1999,18 @@ config FB_IBM_GXT4500
>   	  doesn't use Geometry Engine GT1000. This driver also supports
>   	  AGP Fire GL2/3/4 cards on x86.
>   
> +# FIXME FB_SYS_*
> +config FB_PS2
> +	tristate "Frame buffer driver for Sony Playstation 2"
> +	depends on FB && SONY_PS2
> +	select PS2_GS
> +	select FB_TILEBLITTING
> +	default y
> +	help
> +	  Frame buffer driver for the Sony Playstation 2 Graphics Synthesizer.
> +	  Memory mapping is not supported since the frame buffer is local to
> +	  the GS.
> +
>   config FB_PS3
>   	tristate "PS3 GPU framebuffer driver"
>   	depends on FB && PS3_PS3AV
> diff --git a/drivers/video/fbdev/Makefile b/drivers/video/fbdev/Makefile
> index 7dc4861a93e6..1e55fa8ca4af 100644
> --- a/drivers/video/fbdev/Makefile
> +++ b/drivers/video/fbdev/Makefile
> @@ -105,6 +105,7 @@ obj-$(CONFIG_FB_S3C2410)	  += s3c2410fb.o
>   obj-$(CONFIG_FB_FSL_DIU)	  += fsl-diu-fb.o
>   obj-$(CONFIG_FB_COBALT)           += cobalt_lcdfb.o
>   obj-$(CONFIG_FB_IBM_GXT4500)	  += gxt4500.o
> +obj-$(CONFIG_FB_PS2)		  += ps2fb.o
>   obj-$(CONFIG_FB_PS3)		  += ps3fb.o
>   obj-$(CONFIG_FB_SM501)            += sm501fb.o
>   obj-$(CONFIG_FB_UDL)		  += udlfb.o
> diff --git a/drivers/video/fbdev/ps2fb.c b/drivers/video/fbdev/ps2fb.c
> new file mode 100644
> index 000000000000..7bfbc3c2aa4d
> --- /dev/null
> +++ b/drivers/video/fbdev/ps2fb.c
> @@ -0,0 +1,533 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * PlayStation 2 frame buffer driver
> + *
> + * Copyright (C) 2019 Fredrik Noring
> + */
> +
> +/**
> + * DOC: The PlayStation 2 frame buffer console
> + *
> + * The frame buffer supports a tiled frame buffer console. The main limitation
> + * is the lack of memory mapping (mmap), since the Graphics Synthesizer has
> + * local frame buffer memory that is not directly accessible from the main bus.
> + * The GS has 4 MiB of local memory.
> + *
> + * The console drawing primitives are synchronous to allow printk at any time.
> + * This is highly useful for debugging but it is not the fastest possible
> + * implementation. The console is nevertheless very fast and makes use of
> + * several hardware accelerated features of the Graphics Synthesizer.
> + *
> + * The maximum practical resolution is 1920x1080p at 16 bits per pixel that
> + * requires 4147200 bytes of local memory, leaving 47104 bytes for a tiled
> + * font, which at 8x8 pixels and a minimum 4 bits indexed texture palette is
> + * at most 1464 characters. The indexed palette makes switching colours easy.
> + * &struct fb_tile_ops is accelerated with GS texture sprites that are fast
> + * (GS local copy) for the kernel via simple DMA GS commands via the GIF.
> + *
> + * The local memory is organised as follows: first comes the display buffer,
> + * then one block of a palette, and finally the font installed as a texture.
> + *
> + * All frame buffer transmissions are done by DMA via GIF PATH3.
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/delay.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/interrupt.h>
> +#include <linux/errno.h>
> +#include <linux/fb.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/mm.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/string.h>
> +#include <linux/uaccess.h>
> +
> +#include <asm/io.h>
> +
> +#include <asm/mach-ps2/dmac.h>
> +#include <asm/mach-ps2/gif.h>
> +#include <asm/mach-ps2/gs.h>
> +#include <asm/mach-ps2/gs-registers.h>
> +
> +#include <uapi/asm/gif.h>
> +#include <uapi/asm/gs.h>
> +
> +#define DEVICE_NAME "ps2fb"
> +
> +#define PALETTE_BLOCK_COUNT 1	/* One block is used for the indexed colors */
> +
> +/* Module parameters */
> +static char *mode_option;
> +
> +union package {
> +	union gif_data gif;
> +	struct dma_tag dma;
> +};
> +
> +/**
> + * struct tile_texture - texture representing a tile
> + * @tbp: texture base pointer
> + * @u: texel u coordinate (x coordinate)
> + * @v: texel v coordinate (y coordinate)
> + */
> +struct tile_texture {
> +	u32 tbp;
> +	u32 u;
> +	u32 v;
> +};
> +
> +/**
> + * struct console_buffer - console buffer
> + * @block_count: number of frame buffer blocks
> + * @bg: background color index
> + * @fg: foreground color index
> + * @tile: tile dimensions
> + * @tile.width: width in pixels
> + * @tile.height: height in pixels
> + * @tile.width2: least width in pixels, power of 2
> + * @tile.height2: least height in pixels, power of 2
> + * @tile.block: tiles are stored as textures in the PSMT4 pixel storage format
> + * 	with both cols and rows as powers of 2
> + * @tile.block.cols: tile columns per GS block
> + * @tile.block.rows: tile rows per GS block
> + */
> +struct console_buffer {
> +	u32 block_count;
> +
> +	u32 bg;
> +	u32 fg;
> +
> +	struct cb_tile {
> +		u32 width;
> +		u32 height;
> +
> +		u32 width2;
> +		u32 height2;
> +
> +		struct {
> +			u32 cols;
> +			u32 rows;
> +		} block;
> +	} tile;
> +};
> +
> +/**
> + * struct ps2fb_par - driver specific structure
> + * @lock: spin lock to be taken for all structure operations
> + * @cb: console buffer definition
> + * @package: tags and datafor the GIF
> + * @package.capacity: maximum number of GIF packages in 16-byte unit
> + * @package.buffer: DMA buffer for GIF packages
> + */
> +struct ps2fb_par {
> +	spinlock_t lock;
> +
> +	struct console_buffer cb;
> +
> +	struct {
> +		size_t capacity;
> +		union package *buffer;
> +	} package;
> +};
> +
> +/**
> + * texture_least_power_of_2 - round up to a power of 2, not less than 8
> + * @n: integer to round up
> + *
> + * Return: least integer that is a power of 2 and not less than @n or 8
> + */
> +static u32 texture_least_power_of_2(u32 n)
> +{
> +	return max(1 << get_count_order(n), 8);
> +}
> +
> +/**
> + * cb_tile - create a console buffer tile object
> + * @width: width of tile in pixels
> + * @height: height of tile in pixels
> + *
> + * Return: a console buffer tile object with the given width and height
> + */
> +static struct cb_tile cb_tile(u32 width, u32 height)
> +{
> +	const u32 width2 = texture_least_power_of_2(width);
> +	const u32 height2 = texture_least_power_of_2(height);
> +
> +	return (struct cb_tile) {
> +		.width = width,
> +		.height = height,
> +
> +		.width2 = width2,
> +		.height2 = height2,
> +
> +		.block = {
> +			.cols = GS_PSMT4_BLOCK_WIDTH / width2,
> +			.rows = GS_PSMT4_BLOCK_HEIGHT / height2,
> +		},
> +	};
> +}
> +
> +/**
> + * display_buffer_size - display buffer size for a given video resolution
> + *
> + * This calculation is a lower bound estimate. A precise calculation would have
> + * to take memory pages, blocks and column arrangements into account. To choose
> + * the appropriate standard video mode such details can be disregarded, though.
> + *
> + * Return: the size in bytes of the display buffer
> + */
> +static u32 display_buffer_size(const u32 xres_virtual, const u32 yres_virtual,
> +      const u32 bits_per_pixel)
> +{
> +	return (xres_virtual * yres_virtual * bits_per_pixel) / 8;
> +}
> +
> +/**
> + * ps2fb_cb_get_tilemax - maximum number of tiles
> + * @info: frame buffer info object
> + *
> + * Return: the maximum number of tiles
> + */
> +static int ps2fb_cb_get_tilemax(struct fb_info *info)
> +{
> +	const struct ps2fb_par *par = info->par;
> +	const u32 block_tile_count =
> +		par->cb.tile.block.cols *
> +		par->cb.tile.block.rows;
> +	const s32 blocks_available =
> +		GS_BLOCK_COUNT - par->cb.block_count - PALETTE_BLOCK_COUNT;
> +
> +	return blocks_available > 0 ? blocks_available * block_tile_count : 0;
> +}
> +
> +/**
> + * bits_per_pixel_fits - does the given resolution fit the given buffer size?
> + * @xres_virtual: virtual x resolution in pixels
> + * @yres_virtual: virtual y resolution in pixels
> + * @bits_per_pixel: number of bits per pixel
> + * @buffer_size: size in bytes of display buffer
> + *
> + * The size calculation is approximate, but accurate enough for the standard
> + * video modes.
> + *
> + * Return: %true if the resolution fits the given buffer size, otherwise %false
> + */
> +static bool bits_per_pixel_fits(const u32 xres_virtual, const u32 yres_virtual,
> +      const int bits_per_pixel, const size_t buffer_size)
> +{
> +	return display_buffer_size(xres_virtual, yres_virtual,
> +		bits_per_pixel) <= buffer_size;
> +}
> +
> +/**
> + * default_bits_per_pixel - choose either 16 or 32 bits per pixel
> + * @xres_virtual: virtual x resolution in pixels
> + * @yres_virtual: virtual y resolution in pixels
> + * @buffer_size: size in bytes of display buffer
> + *
> + * 32 bits per pixel is returned unless this does not fit the given buffer size.
> + *
> + * The size calculation is approximate, but accurate enough for the standard
> + * video modes.
> + *
> + * Return: 16 or 32 bits per pixel
> + */
> +static int default_bits_per_pixel(
> +	const u32 xres_virtual, const u32 yres_virtual,
> +	const size_t buffer_size)
> +{
> +	return bits_per_pixel_fits(xres_virtual, yres_virtual,
> +		32, buffer_size) ? 32 : 16;
> +}
> +
> +/**
> + * filled_var_videomode - is the screen info video mode filled in?
> + * @var: screen info object to check
> + *
> + * Return: %true if the video mode is filled in, otherwise %false
> + */
> +static bool filled_var_videomode(const struct fb_var_screeninfo *var)
> +{
> +	return var->xres > 0 && var->hsync_len > 0 &&
> +	       var->yres > 0 && var->vsync_len > 0 && var->pixclock > 0;
> +}
> +
> +static int ps2fb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
> +{
> +	/* Check whether video mode defaults are needed. */
> +	if (!filled_var_videomode(var)) {
> +		const struct fb_videomode *vm =
> +			fb_find_best_mode(var, &info->modelist);
> +
> +		if (!vm)
> +			return -EINVAL;
> +
> +		fb_videomode_to_var(var, vm);
> +	}
> +
> +        /* GS video register resolution is limited to 2048. */
> +        if (var->xres < 1 || 2048 < var->xres ||
> +	    var->yres < 1 || 2048 < var->yres)
> +		return -EINVAL;
> +
> +	var->xres_virtual = var->xres;
> +	var->yres_virtual = var->yres;
> +	var->xoffset = 0;
> +	var->yoffset = 0;
> +
> +        /* Check bits per pixel. */
> +        if (!var->bits_per_pixel)
> +		var->bits_per_pixel = default_bits_per_pixel(
> +		     var->xres_virtual, var->yres_virtual, info->fix.smem_len);
> +	else if (var->bits_per_pixel != 16 &&
> +		 var->bits_per_pixel != 32)
> +		return -EINVAL;
> +        if (!bits_per_pixel_fits(var->xres_virtual, var->yres_virtual,
> +			var->bits_per_pixel, info->fix.smem_len))
> +		var->bits_per_pixel = default_bits_per_pixel(
> +		     var->xres_virtual, var->yres_virtual, info->fix.smem_len);
> +        if (!bits_per_pixel_fits(var->xres_virtual, var->yres_virtual,
> +			var->bits_per_pixel, info->fix.smem_len))
> +		return -ENOMEM;
> +	if (var->bits_per_pixel == 16) {
> +		var->red    = (struct fb_bitfield){ .offset =  0, .length = 5 };
> +		var->green  = (struct fb_bitfield){ .offset =  5, .length = 5 };
> +		var->blue   = (struct fb_bitfield){ .offset = 10, .length = 5 };
> +		var->transp = (struct fb_bitfield){ .offset = 15, .length = 1 };
> +	} else if (var->bits_per_pixel == 32) {
> +		var->red    = (struct fb_bitfield){ .offset =  0, .length = 8 };
> +		var->green  = (struct fb_bitfield){ .offset =  8, .length = 8 };
> +		var->blue   = (struct fb_bitfield){ .offset = 16, .length = 8 };
> +		var->transp = (struct fb_bitfield){ .offset = 24, .length = 8 };
> +	} else
> +		return -EINVAL;		/* Unsupported bits per pixel. */
> +
> +        /* Screen rotations are not supported. */
> +	if (var->rotate)
> +		return -EINVAL;
> +
> +        return 0;
> +}
> +
> +static int ps2fb_cb_check_var(
> +	struct fb_var_screeninfo *var, struct fb_info *info)
> +{
> +	struct ps2fb_par *par = info->par;
> +	unsigned long flags;
> +	int err;
> +
> +	spin_lock_irqsave(&par->lock, flags);
> +	err = ps2fb_check_var(var, info);
> +	spin_unlock_irqrestore(&par->lock, flags);
> +
> +	if (!err && info->tileops)
> +		if (info->tileops->fb_get_tilemax(info) < 256)
> +			err = -ENOMEM;
> +
> +	return err;
> +}
> +
> +static u32 block_dimensions(u32 dim, u32 alignment)
> +{
> +	u32 mask = 0;
> +	u32 d;
> +
> +	for (d = 1; d <= dim; d++)
> +		if (d % alignment == 0)
> +			mask |= 1 << (d - 1);
> +
> +	return mask;
> +}
> +
> +static int init_console_buffer(struct platform_device *pdev,
> +	struct fb_info *info)
> +{
> +	static struct fb_ops fbops = {
> +		.owner		= THIS_MODULE,
> +		.fb_check_var	= ps2fb_cb_check_var,
> +	};
> +
> +	static struct fb_tile_ops tileops = {
> +		.fb_get_tilemax = ps2fb_cb_get_tilemax
> +	};
> +
> +	struct ps2fb_par *par = info->par;
> +
> +	fb_info(info, "Graphics Synthesizer console frame buffer device\n");
> +
> +	info->screen_size = 0;
> +	info->screen_base = NULL;	/* mmap is unsupported by hardware */
> +
> +	info->fix.smem_start = 0;	/* GS frame buffer is local memory */
> +	info->fix.smem_len = GS_MEMORY_SIZE;
> +
> +	info->fbops = &fbops;
> +	info->flags = FBINFO_DEFAULT |
> +		      FBINFO_READS_FAST;
> +
> +	info->flags |= FBINFO_MISC_TILEBLITTING;
> +	info->tileops = &tileops;
> +
> +	/*
> +	 * BITBLTBUF for pixel format CT32 requires divisibility by 2,
> +	 * and CT16 requires divisibility by 4. So 4 is a safe choice.
> +	 */
> +	info->pixmap.blit_x = block_dimensions(GS_PSMT4_BLOCK_WIDTH, 4);
> +	info->pixmap.blit_y = block_dimensions(GS_PSMT4_BLOCK_HEIGHT, 1);
> +
> +	/* 8x8 default font tile size for fb_get_tilemax */
> +	par->cb.tile = cb_tile(8, 8);
> +
> +	return 0;
> +}
> +
> +static int ps2fb_probe(struct platform_device *pdev)
> +{
> +	struct ps2fb_par *par;
> +	struct fb_info *info;
> +	int err;
> +
> +	info = framebuffer_alloc(sizeof(*par), &pdev->dev);
> +	if (info == NULL) {
> +		dev_err(&pdev->dev, "framebuffer_alloc failed\n");
> +		err = -ENOMEM;
> +		goto err_framebuffer_alloc;
> +	}
> +
> +	par = info->par;
> +
> +	spin_lock_init(&par->lock);
> +
> +	par->package.buffer = (union package *)__get_free_page(GFP_DMA);
> +	if (!par->package.buffer) {
> +		dev_err(&pdev->dev, "Failed to allocate package buffer\n");
> +		err = -ENOMEM;
> +		goto err_package_buffer;
> +	}
> +	par->package.capacity = PAGE_SIZE / sizeof(union package);
> +
> +	strlcpy(info->fix.id, "PS2 GS", ARRAY_SIZE(info->fix.id));
> +	info->fix.accel = FB_ACCEL_PLAYSTATION_2;
> +
> +	err = init_console_buffer(pdev, info);
> +	if (err < 0)
> +		goto err_init_buffer;
> +
> +	info->mode = &par->mode;
> +
> +	if (register_framebuffer(info) < 0) {
> +		fb_err(info, "register_framebuffer failed\n");
> +		err = -EINVAL;
> +		goto err_register_framebuffer;
> +	}
> +
> +	platform_set_drvdata(pdev, info);
> +
> +	return 0;
> +
> +err_register_framebuffer:
> +err_init_buffer:
> +	free_page((unsigned long)par->package.buffer);
> +err_package_buffer:
> +	framebuffer_release(info);
> +err_framebuffer_alloc:
> +	return err;
> +}
> +
> +static int ps2fb_remove(struct platform_device *pdev)
> +{
> +	struct fb_info *info = platform_get_drvdata(pdev);
> +	struct ps2fb_par *par = info->par;
> +	int err = 0;
> +
> +	if (info != NULL) {
> +		unregister_framebuffer(info);
> +		fb_dealloc_cmap(&info->cmap);
> +
> +		framebuffer_release(info);
> +	}
> +
> +	if (!gif_wait()) {
> +		fb_err(info, "Failed to complete GIF DMA transfer\n");
> +		err = -EBUSY;
> +	}
> +	free_page((unsigned long)par->package.buffer);
> +
> +	return err;
> +}
> +
> +static struct platform_driver ps2fb_driver = {
> +	.probe		= ps2fb_probe,
> +	.remove		= ps2fb_remove,
> +	.driver = {
> +		.name	= DEVICE_NAME,
> +	},
> +};
> +
> +static struct platform_device *ps2fb_device;
> +
> +static int __init ps2fb_init(void)
> +{
> +	int err;
> +
> +#ifndef MODULE
> +	char *options = NULL;
> +	char *this_opt;
> +
> +	if (fb_get_options(DEVICE_NAME, &options))
> +		return -ENODEV;
> +	if (!options || !*options)
> +		goto no_options;
> +
> +	while ((this_opt = strsep(&options, ",")) != NULL) {
> +		if (!*this_opt)
> +			continue;
> +
> +		if (!strncmp(this_opt, "mode_option:", 12))
> +			mode_option = &this_opt[12];
> +		else if ('0' <= this_opt[0] && this_opt[0] <= '9')
> +			mode_option = this_opt;
> +		else
> +			pr_warn(DEVICE_NAME ": Unrecognized option \"%s\"\n",
> +				this_opt);
> +	}
> +
> +no_options:
> +#endif /* !MODULE */
> +
> +	/* Default to a suitable PAL or NTSC broadcast mode. */
> +	if (!mode_option)
> +		mode_option = gs_region_pal() ? "576x460i@50" : "576x384i@60";
> +
> +	ps2fb_device = platform_device_alloc("ps2fb", 0);
> +	if (!ps2fb_device)
> +		return -ENOMEM;
> +
> +	err = platform_device_add(ps2fb_device);
> +	if (err < 0) {
> +		platform_device_put(ps2fb_device);
> +		return err;
> +	}
> +
> +	return platform_driver_register(&ps2fb_driver);
> +}
> +
> +static void __exit ps2fb_exit(void)
> +{
> +	platform_driver_unregister(&ps2fb_driver);
> +	platform_device_unregister(ps2fb_device);
> +}
> +
> +module_init(ps2fb_init);
> +module_exit(ps2fb_exit);
> +
> +module_param(mode_option, charp, 0);
> +MODULE_PARM_DESC(mode_option,
> +	"Specify initial video mode as \"<xres>x<yres>[-<bpp>][@<refresh>]\"");
> +
> +MODULE_DESCRIPTION("PlayStation 2 frame buffer driver");
> +MODULE_AUTHOR("Fredrik Noring");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/console_struct.h b/include/linux/console_struct.h
> index 24d4c16e3ae0..cb562672cc3a 100644
> --- a/include/linux/console_struct.h
> +++ b/include/linux/console_struct.h
> @@ -13,9 +13,11 @@
>   #ifndef _LINUX_CONSOLE_STRUCT_H
>   #define _LINUX_CONSOLE_STRUCT_H
>   
> +#include <linux/tty.h>
>   #include <linux/wait.h>
>   #include <linux/vt.h>
>   #include <linux/workqueue.h>
> +#include <uapi/linux/kd.h>
>   
>   struct uni_pagedir;
>   struct uni_screen;
> diff --git a/include/uapi/linux/fb.h b/include/uapi/linux/fb.h
> index b6aac7ee1f67..38d88eebf651 100644
> --- a/include/uapi/linux/fb.h
> +++ b/include/uapi/linux/fb.h
> @@ -149,6 +149,7 @@
>   #define FB_ACCEL_SUPERSAVAGE    0x8c    /* S3 Supersavage               */
>   #define FB_ACCEL_PROSAVAGE_DDR  0x8d	/* S3 ProSavage DDR             */
>   #define FB_ACCEL_PROSAVAGE_DDRK 0x8e	/* S3 ProSavage DDR-K           */
> +#define FB_ACCEL_PLAYSTATION_2  0x8f	/* PlayStation 2                */
>   
>   #define FB_ACCEL_PUV3_UNIGFX	0xa0	/* PKUnity-v3 Unigfx		*/
>