goldfishfb.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) 2007 Google, Inc.
  4 * Copyright (C) 2012 Intel, Inc.
  5 */
  6
  7#include <linux/module.h>
  8#include <linux/kernel.h>
  9#include <linux/dma-mapping.h>
 10#include <linux/errno.h>
 11#include <linux/string.h>
 12#include <linux/slab.h>
 13#include <linux/delay.h>
 14#include <linux/mm.h>
 15#include <linux/fb.h>
 16#include <linux/init.h>
 17#include <linux/interrupt.h>
 18#include <linux/ioport.h>
 19#include <linux/platform_device.h>
 20#include <linux/acpi.h>
 21
 22enum {
 23	FB_GET_WIDTH        = 0x00,
 24	FB_GET_HEIGHT       = 0x04,
 25	FB_INT_STATUS       = 0x08,
 26	FB_INT_ENABLE       = 0x0c,
 27	FB_SET_BASE         = 0x10,
 28	FB_SET_ROTATION     = 0x14,
 29	FB_SET_BLANK        = 0x18,
 30	FB_GET_PHYS_WIDTH   = 0x1c,
 31	FB_GET_PHYS_HEIGHT  = 0x20,
 32
 33	FB_INT_VSYNC             = 1U << 0,
 34	FB_INT_BASE_UPDATE_DONE  = 1U << 1
 35};
 36
 37struct goldfish_fb {
 38	void __iomem *reg_base;
 39	int irq;
 40	spinlock_t lock;
 41	wait_queue_head_t wait;
 42	int base_update_count;
 43	int rotation;
 44	struct fb_info fb;
 45	u32 cmap[16];
 46};
 47
 48static irqreturn_t goldfish_fb_interrupt(int irq, void *dev_id)
 49{
 50	unsigned long irq_flags;
 51	struct goldfish_fb *fb = dev_id;
 52	u32 status;
 53
 54	spin_lock_irqsave(&fb->lock, irq_flags);
 55	status = readl(fb->reg_base + FB_INT_STATUS);
 56	if (status & FB_INT_BASE_UPDATE_DONE) {
 57		fb->base_update_count++;
 58		wake_up(&fb->wait);
 59	}
 60	spin_unlock_irqrestore(&fb->lock, irq_flags);
 61	return status ? IRQ_HANDLED : IRQ_NONE;
 62}
 63
 64static inline u32 convert_bitfield(int val, struct fb_bitfield *bf)
 65{
 66	unsigned int mask = (1 << bf->length) - 1;
 67
 68	return (val >> (16 - bf->length) & mask) << bf->offset;
 69}
 70
 71static int
 72goldfish_fb_setcolreg(unsigned int regno, unsigned int red, unsigned int green,
 73		 unsigned int blue, unsigned int transp, struct fb_info *info)
 74{
 75	struct goldfish_fb *fb = container_of(info, struct goldfish_fb, fb);
 76
 77	if (regno < 16) {
 78		fb->cmap[regno] = convert_bitfield(transp, &fb->fb.var.transp) |
 79				  convert_bitfield(blue, &fb->fb.var.blue) |
 80				  convert_bitfield(green, &fb->fb.var.green) |
 81				  convert_bitfield(red, &fb->fb.var.red);
 82		return 0;
 83	} else {
 84		return 1;
 85	}
 86}
 87
 88static int goldfish_fb_check_var(struct fb_var_screeninfo *var,
 89							struct fb_info *info)
 90{
 91	if ((var->rotate & 1) != (info->var.rotate & 1)) {
 92		if ((var->xres != info->var.yres) ||
 93				(var->yres != info->var.xres) ||
 94				(var->xres_virtual != info->var.yres) ||
 95				(var->yres_virtual > info->var.xres * 2) ||
 96				(var->yres_virtual < info->var.xres)) {
 97			return -EINVAL;
 98		}
 99	} else {
100		if ((var->xres != info->var.xres) ||
101		   (var->yres != info->var.yres) ||
102		   (var->xres_virtual != info->var.xres) ||
103		   (var->yres_virtual > info->var.yres * 2) ||
104		   (var->yres_virtual < info->var.yres)) {
105			return -EINVAL;
106		}
107	}
108	if ((var->xoffset != info->var.xoffset) ||
109			(var->bits_per_pixel != info->var.bits_per_pixel) ||
110			(var->grayscale != info->var.grayscale)) {
111		return -EINVAL;
112	}
113	return 0;
114}
115
116static int goldfish_fb_set_par(struct fb_info *info)
117{
118	struct goldfish_fb *fb = container_of(info, struct goldfish_fb, fb);
119
120	if (fb->rotation != fb->fb.var.rotate) {
121		info->fix.line_length = info->var.xres * 2;
122		fb->rotation = fb->fb.var.rotate;
123		writel(fb->rotation, fb->reg_base + FB_SET_ROTATION);
124	}
125	return 0;
126}
127
128
129static int goldfish_fb_pan_display(struct fb_var_screeninfo *var,
130							struct fb_info *info)
131{
132	unsigned long irq_flags;
133	int base_update_count;
134	struct goldfish_fb *fb = container_of(info, struct goldfish_fb, fb);
135
136	spin_lock_irqsave(&fb->lock, irq_flags);
137	base_update_count = fb->base_update_count;
138	writel(fb->fb.fix.smem_start + fb->fb.var.xres * 2 * var->yoffset,
139						fb->reg_base + FB_SET_BASE);
140	spin_unlock_irqrestore(&fb->lock, irq_flags);
141	wait_event_timeout(fb->wait,
142			fb->base_update_count != base_update_count, HZ / 15);
143	if (fb->base_update_count == base_update_count)
144		pr_err("%s: timeout waiting for base update\n", __func__);
145	return 0;
146}
147
148static int goldfish_fb_blank(int blank, struct fb_info *info)
149{
150	struct goldfish_fb *fb = container_of(info, struct goldfish_fb, fb);
151
152	switch (blank) {
153	case FB_BLANK_NORMAL:
154		writel(1, fb->reg_base + FB_SET_BLANK);
155		break;
156	case FB_BLANK_UNBLANK:
157		writel(0, fb->reg_base + FB_SET_BLANK);
158		break;
159	}
160	return 0;
161}
162
163static const struct fb_ops goldfish_fb_ops = {
164	.owner          = THIS_MODULE,
165	FB_DEFAULT_IOMEM_OPS,
166	.fb_check_var   = goldfish_fb_check_var,
167	.fb_set_par     = goldfish_fb_set_par,
168	.fb_setcolreg   = goldfish_fb_setcolreg,
169	.fb_pan_display = goldfish_fb_pan_display,
170	.fb_blank	= goldfish_fb_blank,
171};
172
173
174static int goldfish_fb_probe(struct platform_device *pdev)
175{
176	int ret;
177	struct resource *r;
178	struct goldfish_fb *fb;
179	size_t framesize;
180	u32 width, height;
181	dma_addr_t fbpaddr;
182
183	fb = kzalloc(sizeof(*fb), GFP_KERNEL);
184	if (fb == NULL) {
185		ret = -ENOMEM;
186		goto err_fb_alloc_failed;
187	}
188	spin_lock_init(&fb->lock);
189	init_waitqueue_head(&fb->wait);
190	platform_set_drvdata(pdev, fb);
191
192	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
193	if (r == NULL) {
194		ret = -ENODEV;
195		goto err_no_io_base;
196	}
197	fb->reg_base = ioremap(r->start, PAGE_SIZE);
198	if (fb->reg_base == NULL) {
199		ret = -ENOMEM;
200		goto err_no_io_base;
201	}
202
203	fb->irq = platform_get_irq(pdev, 0);
204	if (fb->irq < 0) {
205		ret = fb->irq;
206		goto err_no_irq;
207	}
208
209	width = readl(fb->reg_base + FB_GET_WIDTH);
210	height = readl(fb->reg_base + FB_GET_HEIGHT);
211
212	fb->fb.fbops		= &goldfish_fb_ops;
213	fb->fb.pseudo_palette	= fb->cmap;
214	fb->fb.fix.type		= FB_TYPE_PACKED_PIXELS;
215	fb->fb.fix.visual = FB_VISUAL_TRUECOLOR;
216	fb->fb.fix.line_length = width * 2;
217	fb->fb.fix.accel	= FB_ACCEL_NONE;
218	fb->fb.fix.ypanstep = 1;
219
220	fb->fb.var.xres		= width;
221	fb->fb.var.yres		= height;
222	fb->fb.var.xres_virtual	= width;
223	fb->fb.var.yres_virtual	= height * 2;
224	fb->fb.var.bits_per_pixel = 16;
225	fb->fb.var.activate	= FB_ACTIVATE_NOW;
226	fb->fb.var.height	= readl(fb->reg_base + FB_GET_PHYS_HEIGHT);
227	fb->fb.var.width	= readl(fb->reg_base + FB_GET_PHYS_WIDTH);
228	fb->fb.var.pixclock	= 0;
229
230	fb->fb.var.red.offset = 11;
231	fb->fb.var.red.length = 5;
232	fb->fb.var.green.offset = 5;
233	fb->fb.var.green.length = 6;
234	fb->fb.var.blue.offset = 0;
235	fb->fb.var.blue.length = 5;
236
237	framesize = width * height * 2 * 2;
238	fb->fb.screen_base = (char __force __iomem *)dma_alloc_coherent(
239						&pdev->dev, framesize,
240						&fbpaddr, GFP_KERNEL);
241	pr_debug("allocating frame buffer %d * %d, got %p\n",
242					width, height, fb->fb.screen_base);
243	if (fb->fb.screen_base == NULL) {
244		ret = -ENOMEM;
245		goto err_alloc_screen_base_failed;
246	}
247	fb->fb.fix.smem_start = fbpaddr;
248	fb->fb.fix.smem_len = framesize;
249
250	ret = fb_set_var(&fb->fb, &fb->fb.var);
251	if (ret)
252		goto err_fb_set_var_failed;
253
254	ret = request_irq(fb->irq, goldfish_fb_interrupt, IRQF_SHARED,
255							pdev->name, fb);
256	if (ret)
257		goto err_request_irq_failed;
258
259	writel(FB_INT_BASE_UPDATE_DONE, fb->reg_base + FB_INT_ENABLE);
260	goldfish_fb_pan_display(&fb->fb.var, &fb->fb); /* updates base */
261
262	ret = register_framebuffer(&fb->fb);
263	if (ret)
264		goto err_register_framebuffer_failed;
265	return 0;
266
267err_register_framebuffer_failed:
268	free_irq(fb->irq, fb);
269err_request_irq_failed:
270err_fb_set_var_failed:
271	dma_free_coherent(&pdev->dev, framesize,
272				(void *)fb->fb.screen_base,
273				fb->fb.fix.smem_start);
274err_alloc_screen_base_failed:
275err_no_irq:
276	iounmap(fb->reg_base);
277err_no_io_base:
278	kfree(fb);
279err_fb_alloc_failed:
280	return ret;
281}
282
283static void goldfish_fb_remove(struct platform_device *pdev)
284{
285	size_t framesize;
286	struct goldfish_fb *fb = platform_get_drvdata(pdev);
287
288	framesize = fb->fb.var.xres_virtual * fb->fb.var.yres_virtual * 2;
289	unregister_framebuffer(&fb->fb);
290	free_irq(fb->irq, fb);
291
292	dma_free_coherent(&pdev->dev, framesize, (void *)fb->fb.screen_base,
293						fb->fb.fix.smem_start);
294	iounmap(fb->reg_base);
295	kfree(fb);
296}
297
298static const struct of_device_id goldfish_fb_of_match[] = {
299	{ .compatible = "google,goldfish-fb", },
300	{},
301};
302MODULE_DEVICE_TABLE(of, goldfish_fb_of_match);
303
304#ifdef CONFIG_ACPI
305static const struct acpi_device_id goldfish_fb_acpi_match[] = {
306	{ "GFSH0004", 0 },
307	{ },
308};
309MODULE_DEVICE_TABLE(acpi, goldfish_fb_acpi_match);
310#endif
311
312static struct platform_driver goldfish_fb_driver = {
313	.probe		= goldfish_fb_probe,
314	.remove		= goldfish_fb_remove,
315	.driver = {
316		.name = "goldfish_fb",
317		.of_match_table = goldfish_fb_of_match,
318		.acpi_match_table = ACPI_PTR(goldfish_fb_acpi_match),
319	}
320};
321
322module_platform_driver(goldfish_fb_driver);
323
324MODULE_DESCRIPTION("Goldfish Virtual Platform Framebuffer driver");
325MODULE_LICENSE("GPL v2");