sample: vfio mdev display - guest driver

	  mediated device.  It is a simple framebuffer and supports

	  the region display interface (VFIO_GFX_PLANE_TYPE_REGION).

config SAMPLE_VFIO_MDEV_MDPY_FB

	tristate "Build VFIO mdpy example guest fbdev driver -- loadable module only"

	depends on FB && m

	select FB_CFB_FILLRECT

	select FB_CFB_COPYAREA

	select FB_CFB_IMAGEBLIT

	help

	  Guest fbdev driver for the virtual display sample driver.

config SAMPLE_STATX

	bool "Build example extended-stat using code"

	depends on BROKEN

obj-$(CONFIG_SAMPLE_VFIO_MDEV_MTTY) += mtty.o

obj-$(CONFIG_SAMPLE_VFIO_MDEV_MDPY) += mdpy.o

obj-$(CONFIG_SAMPLE_VFIO_MDEV_MDPY_FB) += mdpy-fb.o

// SPDX-License-Identifier: GPL-2.0

/*

 * Framebuffer driver for mdpy (mediated virtual pci display device).

 *

 * See mdpy-defs.h for device specs

 *

 *   (c) Gerd Hoffmann <kraxel@redhat.com>

 *

 * Using some code snippets from simplefb and cirrusfb.

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms and conditions of the GNU General Public License,

 * version 2, as published by the Free Software Foundation.

 *

 * This program is distributed in the hope it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for

 * more details.

 */

#include <linux/errno.h>

#include <linux/fb.h>

#include <linux/io.h>

#include <linux/pci.h>

#include <linux/module.h>

#include <drm/drm_fourcc.h>

#include "mdpy-defs.h"

static const struct fb_fix_screeninfo mdpy_fb_fix = {

	.id		= "mdpy-fb",

	.type		= FB_TYPE_PACKED_PIXELS,

	.visual		= FB_VISUAL_TRUECOLOR,

	.accel		= FB_ACCEL_NONE,

};

static const struct fb_var_screeninfo mdpy_fb_var = {

	.height		= -1,

	.width		= -1,

	.activate	= FB_ACTIVATE_NOW,

	.vmode		= FB_VMODE_NONINTERLACED,

	.bits_per_pixel = 32,

	.transp.offset	= 24,

	.red.offset	= 16,

	.green.offset	= 8,

	.blue.offset	= 0,

	.transp.length	= 8,

	.red.length	= 8,

	.green.length	= 8,

	.blue.length	= 8,

};

#define PSEUDO_PALETTE_SIZE 16

struct mdpy_fb_par {

	u32 palette[PSEUDO_PALETTE_SIZE];

};

static int mdpy_fb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,

			      u_int transp, struct fb_info *info)

{

	u32 *pal = info->pseudo_palette;

	u32 cr = red >> (16 - info->var.red.length);

	u32 cg = green >> (16 - info->var.green.length);

	u32 cb = blue >> (16 - info->var.blue.length);

	u32 value, mask;

	if (regno >= PSEUDO_PALETTE_SIZE)

		return -EINVAL;

	value = (cr << info->var.red.offset) |

		(cg << info->var.green.offset) |

		(cb << info->var.blue.offset);

	if (info->var.transp.length > 0) {

		mask = (1 << info->var.transp.length) - 1;

		mask <<= info->var.transp.offset;

		value |= mask;

	}

	pal[regno] = value;

	return 0;

}

static void mdpy_fb_destroy(struct fb_info *info)

{

	if (info->screen_base)

		iounmap(info->screen_base);

}

static struct fb_ops mdpy_fb_ops = {

	.owner		= THIS_MODULE,

	.fb_destroy	= mdpy_fb_destroy,

	.fb_setcolreg	= mdpy_fb_setcolreg,

	.fb_fillrect	= cfb_fillrect,

	.fb_copyarea	= cfb_copyarea,

	.fb_imageblit	= cfb_imageblit,

};

static int mdpy_fb_probe(struct pci_dev *pdev,

			 const struct pci_device_id *ent)

{

	struct fb_info *info;

	struct mdpy_fb_par *par;

	u32 format, width, height;

	int ret;

	ret = pci_enable_device(pdev);

	if (ret < 0)

		return ret;

	ret = pci_request_regions(pdev, "mdpy-fb");

	if (ret < 0)

		return ret;

	pci_read_config_dword(pdev, MDPY_FORMAT_OFFSET, &format);

	pci_read_config_dword(pdev, MDPY_WIDTH_OFFSET,	&width);

	pci_read_config_dword(pdev, MDPY_HEIGHT_OFFSET, &height);

	if (format != DRM_FORMAT_XRGB8888) {

		pci_err(pdev, "format mismatch (0x%x != 0x%x)\n",

			format, DRM_FORMAT_XRGB8888);

		return -EINVAL;

	}

	if (width < 100	 || width > 10000) {

		pci_err(pdev, "width (%d) out of range\n", width);

		return -EINVAL;

	}

	if (height < 100 || height > 10000) {

		pci_err(pdev, "height (%d) out of range\n", height);

		return -EINVAL;

	}

	pci_info(pdev, "mdpy found: %dx%d framebuffer\n",

		 width, height);

	info = framebuffer_alloc(sizeof(struct mdpy_fb_par), &pdev->dev);

	if (!info)

		goto err_release_regions;

	pci_set_drvdata(pdev, info);

	par = info->par;

	info->fix = mdpy_fb_fix;

	info->fix.smem_start = pci_resource_start(pdev, 0);

	info->fix.smem_len = pci_resource_len(pdev, 0);

	info->fix.line_length = width * 4;

	info->var = mdpy_fb_var;

	info->var.xres = width;

	info->var.yres = height;

	info->var.xres_virtual = width;

	info->var.yres_virtual = height;

	info->screen_size = info->fix.smem_len;

	info->screen_base = ioremap(info->fix.smem_start,

				    info->screen_size);

	if (!info->screen_base) {

		pci_err(pdev, "ioremap(pcibar) failed\n");

		ret = -EIO;

		goto err_release_fb;

	}

	info->apertures = alloc_apertures(1);

	if (!info->apertures) {

		ret = -ENOMEM;

		goto err_unmap;

	}

	info->apertures->ranges[0].base = info->fix.smem_start;

	info->apertures->ranges[0].size = info->fix.smem_len;

	info->fbops = &mdpy_fb_ops;

	info->flags = FBINFO_DEFAULT;

	info->pseudo_palette = par->palette;

	ret = register_framebuffer(info);

	if (ret < 0) {

		pci_err(pdev, "mdpy-fb device register failed: %d\n", ret);

		goto err_unmap;

	}

	pci_info(pdev, "fb%d registered\n", info->node);

	return 0;

err_unmap:

	iounmap(info->screen_base);

err_release_fb:

	framebuffer_release(info);

err_release_regions:

	pci_release_regions(pdev);

	return ret;

}

static void mdpy_fb_remove(struct pci_dev *pdev)

{

	struct fb_info *info = pci_get_drvdata(pdev);

	unregister_framebuffer(info);

	framebuffer_release(info);

}

static struct pci_device_id mdpy_fb_pci_table[] = {

	{

		.vendor	   = MDPY_PCI_VENDOR_ID,

		.device	   = MDPY_PCI_DEVICE_ID,

		.subvendor = MDPY_PCI_SUBVENDOR_ID,

		.subdevice = MDPY_PCI_SUBDEVICE_ID,

	}, {

		/* end of list */

	}

};

static struct pci_driver mdpy_fb_pci_driver = {

	.name		= "mdpy-fb",

	.id_table	= mdpy_fb_pci_table,

	.probe		= mdpy_fb_probe,

	.remove		= mdpy_fb_remove,

};

static int __init mdpy_fb_init(void)

{

	int ret;

	ret = pci_register_driver(&mdpy_fb_pci_driver);

	if (ret)

		return ret;

	return 0;

}

module_init(mdpy_fb_init);

MODULE_DEVICE_TABLE(pci, mdpy_fb_pci_table);

MODULE_LICENSE("GPL v2");