1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Framebuffer driver for mdpy (mediated virtual pci display device).
4 *
5 * See mdpy-defs.h for device specs
6 *
7 *   (c) Gerd Hoffmann <kraxel@redhat.com>
8 *
9 * Using some code snippets from simplefb and cirrusfb.
10 *
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms and conditions of the GNU General Public License,
13 * version 2, as published by the Free Software Foundation.
14 *
15 * This program is distributed in the hope it will be useful, but WITHOUT
16 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
17 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
18 * more details.
19 */
20#include <linux/errno.h>
21#include <linux/fb.h>
22#include <linux/io.h>
23#include <linux/pci.h>
24#include <linux/module.h>
25#include <drm/drm_fourcc.h>
26#include "mdpy-defs.h"
27
28static const struct fb_fix_screeninfo mdpy_fb_fix = {
29	.id		= "mdpy-fb",
30	.type		= FB_TYPE_PACKED_PIXELS,
31	.visual		= FB_VISUAL_TRUECOLOR,
32	.accel		= FB_ACCEL_NONE,
33};
34
35static const struct fb_var_screeninfo mdpy_fb_var = {
36	.height		= -1,
37	.width		= -1,
38	.activate	= FB_ACTIVATE_NOW,
39	.vmode		= FB_VMODE_NONINTERLACED,
40
41	.bits_per_pixel = 32,
42	.transp.offset	= 24,
43	.red.offset	= 16,
44	.green.offset	= 8,
45	.blue.offset	= 0,
46	.transp.length	= 8,
47	.red.length	= 8,
48	.green.length	= 8,
49	.blue.length	= 8,
50};
51
52#define PSEUDO_PALETTE_SIZE 16
53
54struct mdpy_fb_par {
55	u32 palette[PSEUDO_PALETTE_SIZE];
56};
57
58static int mdpy_fb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
59			      u_int transp, struct fb_info *info)
60{
61	u32 *pal = info->pseudo_palette;
62	u32 cr = red >> (16 - info->var.red.length);
63	u32 cg = green >> (16 - info->var.green.length);
64	u32 cb = blue >> (16 - info->var.blue.length);
65	u32 value, mask;
66
67	if (regno >= PSEUDO_PALETTE_SIZE)
68		return -EINVAL;
69
70	value = (cr << info->var.red.offset) |
71		(cg << info->var.green.offset) |
72		(cb << info->var.blue.offset);
73	if (info->var.transp.length > 0) {
74		mask = (1 << info->var.transp.length) - 1;
75		mask <<= info->var.transp.offset;
76		value |= mask;
77	}
78	pal[regno] = value;
79
80	return 0;
81}
82
83static void mdpy_fb_destroy(struct fb_info *info)
84{
85	if (info->screen_base)
86		iounmap(info->screen_base);
87}
88
89static const struct fb_ops mdpy_fb_ops = {
90	.owner		= THIS_MODULE,
91	FB_DEFAULT_IOMEM_OPS,
92	.fb_destroy	= mdpy_fb_destroy,
93	.fb_setcolreg	= mdpy_fb_setcolreg,
94};
95
96static int mdpy_fb_probe(struct pci_dev *pdev,
97			 const struct pci_device_id *ent)
98{
99	struct fb_info *info;
100	struct mdpy_fb_par *par;
101	u32 format, width, height;
102	int ret;
103
104	ret = pci_enable_device(pdev);
105	if (ret < 0)
106		return ret;
107
108	ret = pci_request_regions(pdev, "mdpy-fb");
109	if (ret < 0)
110		goto err_disable_dev;
111
112	pci_read_config_dword(pdev, MDPY_FORMAT_OFFSET, &format);
113	pci_read_config_dword(pdev, MDPY_WIDTH_OFFSET,	&width);
114	pci_read_config_dword(pdev, MDPY_HEIGHT_OFFSET, &height);
115	if (format != DRM_FORMAT_XRGB8888) {
116		pci_err(pdev, "format mismatch (0x%x != 0x%x)\n",
117			format, DRM_FORMAT_XRGB8888);
118		ret = -EINVAL;
119		goto err_release_regions;
120	}
121	if (width < 100	 || width > 10000) {
122		pci_err(pdev, "width (%d) out of range\n", width);
123		ret = -EINVAL;
124		goto err_release_regions;
125	}
126	if (height < 100 || height > 10000) {
127		pci_err(pdev, "height (%d) out of range\n", height);
128		ret = -EINVAL;
129		goto err_release_regions;
130	}
131	pci_info(pdev, "mdpy found: %dx%d framebuffer\n",
132		 width, height);
133
134	info = framebuffer_alloc(sizeof(struct mdpy_fb_par), &pdev->dev);
135	if (!info) {
136		ret = -ENOMEM;
137		goto err_release_regions;
138	}
139	pci_set_drvdata(pdev, info);
140	par = info->par;
141
142	info->fix = mdpy_fb_fix;
143	info->fix.smem_start = pci_resource_start(pdev, 0);
144	info->fix.smem_len = pci_resource_len(pdev, 0);
145	info->fix.line_length = width * 4;
146
147	info->var = mdpy_fb_var;
148	info->var.xres = width;
149	info->var.yres = height;
150	info->var.xres_virtual = width;
151	info->var.yres_virtual = height;
152
153	info->screen_size = info->fix.smem_len;
154	info->screen_base = ioremap(info->fix.smem_start,
155				    info->screen_size);
156	if (!info->screen_base) {
157		pci_err(pdev, "ioremap(pcibar) failed\n");
158		ret = -EIO;
159		goto err_release_fb;
160	}
161
162	info->fbops = &mdpy_fb_ops;
163	info->pseudo_palette = par->palette;
164
165	ret = register_framebuffer(info);
166	if (ret < 0) {
167		pci_err(pdev, "mdpy-fb device register failed: %d\n", ret);
168		goto err_unmap;
169	}
170
171	pci_info(pdev, "fb%d registered\n", info->node);
172	return 0;
173
174err_unmap:
175	iounmap(info->screen_base);
176
177err_release_fb:
178	framebuffer_release(info);
179
180err_release_regions:
181	pci_release_regions(pdev);
182
183err_disable_dev:
184	pci_disable_device(pdev);
185
186	return ret;
187}
188
189static void mdpy_fb_remove(struct pci_dev *pdev)
190{
191	struct fb_info *info = pci_get_drvdata(pdev);
192
193	unregister_framebuffer(info);
194	iounmap(info->screen_base);
195	framebuffer_release(info);
196	pci_release_regions(pdev);
197	pci_disable_device(pdev);
198}
199
200static struct pci_device_id mdpy_fb_pci_table[] = {
201	{
202		.vendor	   = MDPY_PCI_VENDOR_ID,
203		.device	   = MDPY_PCI_DEVICE_ID,
204		.subvendor = MDPY_PCI_SUBVENDOR_ID,
205		.subdevice = MDPY_PCI_SUBDEVICE_ID,
206	}, {
207		/* end of list */
208	}
209};
210
211static struct pci_driver mdpy_fb_pci_driver = {
212	.name		= "mdpy-fb",
213	.id_table	= mdpy_fb_pci_table,
214	.probe		= mdpy_fb_probe,
215	.remove		= mdpy_fb_remove,
216};
217
218static int __init mdpy_fb_init(void)
219{
220	int ret;
221
222	ret = pci_register_driver(&mdpy_fb_pci_driver);
223	if (ret)
224		return ret;
225
226	return 0;
227}
228
229module_init(mdpy_fb_init);
230
231MODULE_DEVICE_TABLE(pci, mdpy_fb_pci_table);
232MODULE_LICENSE("GPL v2");
233