1 files changed, 419 insertions, 0 deletions
diff --git a/drivers/video/fbdev/simplefb.c b/drivers/video/fbdev/simplefb.c
new file mode 100644
index 000000000..1085c0432
--- /dev/null
+++ b/drivers/video/fbdev/simplefb.c
@@ -0,0 +1,419 @@
+/*
+ * Simplest possible simple frame-buffer driver, as a platform device
+ *
+ * Copyright (c) 2013, Stephen Warren
+ *
+ * Based on q40fb.c, which was:
+ * Copyright (C) 2001 Richard Zidlicky <rz@linux-m68k.org>
+ *
+ * Also based on offb.c, which was:
+ * Copyright (C) 1997 Geert Uytterhoeven
+ * Copyright (C) 1996 Paul Mackerras
+ *
+ * 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/module.h>
+#include <linux/platform_data/simplefb.h>
+#include <linux/platform_device.h>
+#include <linux/clk-provider.h>
+#include <linux/of_platform.h>
+
+static struct fb_fix_screeninfo simplefb_fix = {
+	.id		= "simple",
+	.type		= FB_TYPE_PACKED_PIXELS,
+	.visual		= FB_VISUAL_TRUECOLOR,
+	.accel		= FB_ACCEL_NONE,
+};
+
+static struct fb_var_screeninfo simplefb_var = {
+	.height		= -1,
+	.width		= -1,
+	.activate	= FB_ACTIVATE_NOW,
+	.vmode		= FB_VMODE_NONINTERLACED,
+};
+
+#define PSEUDO_PALETTE_SIZE 16
+
+static int simplefb_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;
+
+	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) {
+		u32 mask = (1 << info->var.transp.length) - 1;
+		mask <<= info->var.transp.offset;
+		value |= mask;
+	}
+	pal[regno] = value;
+
+	return 0;
+}
+
+static void simplefb_destroy(struct fb_info *info)
+{
+	if (info->screen_base)
+		iounmap(info->screen_base);
+}
+
+static struct fb_ops simplefb_ops = {
+	.owner		= THIS_MODULE,
+	.fb_destroy	= simplefb_destroy,
+	.fb_setcolreg	= simplefb_setcolreg,
+	.fb_fillrect	= cfb_fillrect,
+	.fb_copyarea	= cfb_copyarea,
+	.fb_imageblit	= cfb_imageblit,
+};
+
+static struct simplefb_format simplefb_formats[] = SIMPLEFB_FORMATS;
+
+struct simplefb_params {
+	u32 width;
+	u32 height;
+	u32 stride;
+	struct simplefb_format *format;
+};
+
+static int simplefb_parse_dt(struct platform_device *pdev,
+			   struct simplefb_params *params)
+{
+	struct device_node *np = pdev->dev.of_node;
+	int ret;
+	const char *format;
+	int i;
+
+	ret = of_property_read_u32(np, "width", &params->width);
+	if (ret) {
+		dev_err(&pdev->dev, "Can't parse width property\n");
+		return ret;
+	}
+
+	ret = of_property_read_u32(np, "height", &params->height);
+	if (ret) {
+		dev_err(&pdev->dev, "Can't parse height property\n");
+		return ret;
+	}
+
+	ret = of_property_read_u32(np, "stride", &params->stride);
+	if (ret) {
+		dev_err(&pdev->dev, "Can't parse stride property\n");
+		return ret;
+	}
+
+	ret = of_property_read_string(np, "format", &format);
+	if (ret) {
+		dev_err(&pdev->dev, "Can't parse format property\n");
+		return ret;
+	}
+	params->format = NULL;
+	for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) {
+		if (strcmp(format, simplefb_formats[i].name))
+			continue;
+		params->format = &simplefb_formats[i];
+		break;
+	}
+	if (!params->format) {
+		dev_err(&pdev->dev, "Invalid format value\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int simplefb_parse_pd(struct platform_device *pdev,
+			     struct simplefb_params *params)
+{
+	struct simplefb_platform_data *pd = dev_get_platdata(&pdev->dev);
+	int i;
+
+	params->width = pd->width;
+	params->height = pd->height;
+	params->stride = pd->stride;
+
+	params->format = NULL;
+	for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) {
+		if (strcmp(pd->format, simplefb_formats[i].name))
+			continue;
+
+		params->format = &simplefb_formats[i];
+		break;
+	}
+
+	if (!params->format) {
+		dev_err(&pdev->dev, "Invalid format value\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+struct simplefb_par {
+	u32 palette[PSEUDO_PALETTE_SIZE];
+#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
+	int clk_count;
+	struct clk **clks;
+#endif
+};
+
+#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
+/*
+ * Clock handling code.
+ *
+ * Here we handle the clocks property of our "simple-framebuffer" dt node.
+ * This is necessary so that we can make sure that any clocks needed by
+ * the display engine that the bootloader set up for us (and for which it
+ * provided a simplefb dt node), stay up, for the life of the simplefb
+ * driver.
+ *
+ * When the driver unloads, we cleanly disable, and then release the clocks.
+ *
+ * We only complain about errors here, no action is taken as the most likely
+ * error can only happen due to a mismatch between the bootloader which set
+ * up simplefb, and the clock definitions in the device tree. Chances are
+ * that there are no adverse effects, and if there are, a clean teardown of
+ * the fb probe will not help us much either. So just complain and carry on,
+ * and hope that the user actually gets a working fb at the end of things.
+ */
+static int simplefb_clocks_init(struct simplefb_par *par,
+				struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct clk *clock;
+	int i, ret;
+
+	if (dev_get_platdata(&pdev->dev) || !np)
+		return 0;
+
+	par->clk_count = of_clk_get_parent_count(np);
+	if (par->clk_count <= 0)
+		return 0;
+
+	par->clks = kcalloc(par->clk_count, sizeof(struct clk *), GFP_KERNEL);
+	if (!par->clks)
+		return -ENOMEM;
+
+	for (i = 0; i < par->clk_count; i++) {
+		clock = of_clk_get(np, i);
+		if (IS_ERR(clock)) {
+			if (PTR_ERR(clock) == -EPROBE_DEFER) {
+				while (--i >= 0) {
+					if (par->clks[i])
+						clk_put(par->clks[i]);
+				}
+				kfree(par->clks);
+				return -EPROBE_DEFER;
+			}
+			dev_err(&pdev->dev, "%s: clock %d not found: %ld\n",
+				__func__, i, PTR_ERR(clock));
+			continue;
+		}
+		par->clks[i] = clock;
+	}
+
+	for (i = 0; i < par->clk_count; i++) {
+		if (par->clks[i]) {
+			ret = clk_prepare_enable(par->clks[i]);
+			if (ret) {
+				dev_err(&pdev->dev,
+					"%s: failed to enable clock %d: %d\n",
+					__func__, i, ret);
+				clk_put(par->clks[i]);
+				par->clks[i] = NULL;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static void simplefb_clocks_destroy(struct simplefb_par *par)
+{
+	int i;
+
+	if (!par->clks)
+		return;
+
+	for (i = 0; i < par->clk_count; i++) {
+		if (par->clks[i]) {
+			clk_disable_unprepare(par->clks[i]);
+			clk_put(par->clks[i]);
+		}
+	}
+
+	kfree(par->clks);
+}
+#else
+static int simplefb_clocks_init(struct simplefb_par *par,
+	struct platform_device *pdev) { return 0; }
+static void simplefb_clocks_destroy(struct simplefb_par *par) { }
+#endif
+
+static int simplefb_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct simplefb_params params;
+	struct fb_info *info;
+	struct simplefb_par *par;
+	struct resource *mem;
+
+	if (fb_get_options("simplefb", NULL))
+		return -ENODEV;
+
+	ret = -ENODEV;
+	if (dev_get_platdata(&pdev->dev))
+		ret = simplefb_parse_pd(pdev, &params);
+	else if (pdev->dev.of_node)
+		ret = simplefb_parse_dt(pdev, &params);
+
+	if (ret)
+		return ret;
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!mem) {
+		dev_err(&pdev->dev, "No memory resource\n");
+		return -EINVAL;
+	}
+
+	info = framebuffer_alloc(sizeof(struct simplefb_par), &pdev->dev);
+	if (!info)
+		return -ENOMEM;
+	platform_set_drvdata(pdev, info);
+
+	par = info->par;
+
+	info->fix = simplefb_fix;
+	info->fix.smem_start = mem->start;
+	info->fix.smem_len = resource_size(mem);
+	info->fix.line_length = params.stride;
+
+	info->var = simplefb_var;
+	info->var.xres = params.width;
+	info->var.yres = params.height;
+	info->var.xres_virtual = params.width;
+	info->var.yres_virtual = params.height;
+	info->var.bits_per_pixel = params.format->bits_per_pixel;
+	info->var.red = params.format->red;
+	info->var.green = params.format->green;
+	info->var.blue = params.format->blue;
+	info->var.transp = params.format->transp;
+
+	info->apertures = alloc_apertures(1);
+	if (!info->apertures) {
+		ret = -ENOMEM;
+		goto error_fb_release;
+	}
+	info->apertures->ranges[0].base = info->fix.smem_start;
+	info->apertures->ranges[0].size = info->fix.smem_len;
+
+	info->fbops = &simplefb_ops;
+	info->flags = FBINFO_DEFAULT | FBINFO_MISC_FIRMWARE;
+	info->screen_base = ioremap_wc(info->fix.smem_start,
+				       info->fix.smem_len);
+	if (!info->screen_base) {
+		ret = -ENOMEM;
+		goto error_fb_release;
+	}
+	info->pseudo_palette = par->palette;
+
+	ret = simplefb_clocks_init(par, pdev);
+	if (ret < 0)
+		goto error_unmap;
+
+	dev_info(&pdev->dev, "framebuffer at 0x%lx, 0x%x bytes, mapped to 0x%p\n",
+			     info->fix.smem_start, info->fix.smem_len,
+			     info->screen_base);
+	dev_info(&pdev->dev, "format=%s, mode=%dx%dx%d, linelength=%d\n",
+			     params.format->name,
+			     info->var.xres, info->var.yres,
+			     info->var.bits_per_pixel, info->fix.line_length);
+
+	ret = register_framebuffer(info);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Unable to register simplefb: %d\n", ret);
+		goto error_clocks;
+	}
+
+	dev_info(&pdev->dev, "fb%d: simplefb registered!\n", info->node);
+
+	return 0;
+
+error_clocks:
+	simplefb_clocks_destroy(par);
+error_unmap:
+	iounmap(info->screen_base);
+error_fb_release:
+	framebuffer_release(info);
+	return ret;
+}
+
+static int simplefb_remove(struct platform_device *pdev)
+{
+	struct fb_info *info = platform_get_drvdata(pdev);
+	struct simplefb_par *par = info->par;
+
+	unregister_framebuffer(info);
+	simplefb_clocks_destroy(par);
+	framebuffer_release(info);
+
+	return 0;
+}
+
+static const struct of_device_id simplefb_of_match[] = {
+	{ .compatible = "simple-framebuffer", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, simplefb_of_match);
+
+static struct platform_driver simplefb_driver = {
+	.driver = {
+		.name = "simple-framebuffer",
+		.of_match_table = simplefb_of_match,
+	},
+	.probe = simplefb_probe,
+	.remove = simplefb_remove,
+};
+
+static int __init simplefb_init(void)
+{
+	int ret;
+	struct device_node *np;
+
+	ret = platform_driver_register(&simplefb_driver);
+	if (ret)
+		return ret;
+
+	if (IS_ENABLED(CONFIG_OF_ADDRESS) && of_chosen) {
+		for_each_child_of_node(of_chosen, np) {
+			if (of_device_is_compatible(np, "simple-framebuffer"))
+				of_platform_device_create(np, NULL, NULL);
+		}
+	}
+
+	return 0;
+}
+
+fs_initcall(simplefb_init);
+
+MODULE_AUTHOR("Stephen Warren <swarren@wwwdotorg.org>");
+MODULE_DESCRIPTION("Simple framebuffer driver");
+MODULE_LICENSE("GPL v2");