Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1102 insertions, 0 deletions

diff --git a/drivers/video/fbdev/acornfb.c b/drivers/video/fbdev/acornfb.c
new file mode 100644
index 0000000000..f0600f6ca2
--- /dev/null
+++ b/drivers/video/fbdev/acornfb.c
@@ -0,0 +1,1102 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/drivers/video/acornfb.c
+ *
+ *  Copyright (C) 1998-2001 Russell King
+ *
+ * Frame buffer code for Acorn platforms
+ *
+ * NOTE: Most of the modes with X!=640 will disappear shortly.
+ * NOTE: Startup setting of HS & VS polarity not supported.
+ *       (do we need to support it if we're coming up in 640x480?)
+ *
+ * FIXME: (things broken by the "new improved" FBCON API)
+ *  - Blanking 8bpp displays with VIDC
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/fb.h>
+#include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
+#include <linux/io.h>
+#include <linux/gfp.h>
+
+#include <mach/hardware.h>
+#include <asm/irq.h>
+#include <asm/mach-types.h>
+
+#include "acornfb.h"
+
+/*
+ * Default resolution.
+ * NOTE that it has to be supported in the table towards
+ * the end of this file.
+ */
+#define DEFAULT_XRES	640
+#define DEFAULT_YRES	480
+#define DEFAULT_BPP	4
+
+/*
+ * define this to debug the video mode selection
+ */
+#undef DEBUG_MODE_SELECTION
+
+/*
+ * Translation from RISC OS monitor types to actual
+ * HSYNC and VSYNC frequency ranges.  These are
+ * probably not right, but they're the best info I
+ * have.  Allow 1% either way on the nominal for TVs.
+ */
+#define NR_MONTYPES	6
+static struct fb_monspecs monspecs[NR_MONTYPES] = {
+	{	/* TV		*/
+		.hfmin	= 15469,
+		.hfmax	= 15781,
+		.vfmin	= 49,
+		.vfmax	= 51,
+	}, {	/* Multi Freq	*/
+		.hfmin	= 0,
+		.hfmax	= 99999,
+		.vfmin	= 0,
+		.vfmax	= 199,
+	}, {	/* Hi-res mono	*/
+		.hfmin	= 58608,
+		.hfmax	= 58608,
+		.vfmin	= 64,
+		.vfmax	= 64,
+	}, {	/* VGA		*/
+		.hfmin	= 30000,
+		.hfmax	= 70000,
+		.vfmin	= 60,
+		.vfmax	= 60,
+	}, {	/* SVGA		*/
+		.hfmin	= 30000,
+		.hfmax	= 70000,
+		.vfmin	= 56,
+		.vfmax	= 75,
+	}, {
+		.hfmin	= 30000,
+		.hfmax	= 70000,
+		.vfmin	= 60,
+		.vfmax	= 60,
+	}
+};
+
+static struct fb_info fb_info;
+static struct acornfb_par current_par;
+static struct vidc_timing current_vidc;
+
+extern unsigned int vram_size;	/* set by setup.c */
+
+#ifdef HAS_VIDC20
+#include <mach/acornfb.h>
+
+#define MAX_SIZE	(2*1024*1024)
+
+/* VIDC20 has a different set of rules from the VIDC:
+ *  hcr  : must be multiple of 4
+ *  hswr : must be even
+ *  hdsr : must be even
+ *  hder : must be even
+ *  vcr  : >= 2, (interlace, must be odd)
+ *  vswr : >= 1
+ *  vdsr : >= 1
+ *  vder : >= vdsr
+ */
+static void acornfb_set_timing(struct fb_info *info)
+{
+	struct fb_var_screeninfo *var = &info->var;
+	struct vidc_timing vidc;
+	u_int vcr, fsize;
+	u_int ext_ctl, dat_ctl;
+	u_int words_per_line;
+
+	memset(&vidc, 0, sizeof(vidc));
+
+	vidc.h_sync_width	= var->hsync_len - 8;
+	vidc.h_border_start	= vidc.h_sync_width + var->left_margin + 8 - 12;
+	vidc.h_display_start	= vidc.h_border_start + 12 - 18;
+	vidc.h_display_end	= vidc.h_display_start + var->xres;
+	vidc.h_border_end	= vidc.h_display_end + 18 - 12;
+	vidc.h_cycle		= vidc.h_border_end + var->right_margin + 12 - 8;
+	vidc.h_interlace	= vidc.h_cycle / 2;
+	vidc.v_sync_width	= var->vsync_len - 1;
+	vidc.v_border_start	= vidc.v_sync_width + var->upper_margin;
+	vidc.v_display_start	= vidc.v_border_start;
+	vidc.v_display_end	= vidc.v_display_start + var->yres;
+	vidc.v_border_end	= vidc.v_display_end;
+	vidc.control		= acornfb_default_control();
+
+	vcr = var->vsync_len + var->upper_margin + var->yres +
+	      var->lower_margin;
+
+	if ((var->vmode & FB_VMODE_MASK) == FB_VMODE_INTERLACED) {
+		vidc.v_cycle = (vcr - 3) / 2;
+		vidc.control |= VIDC20_CTRL_INT;
+	} else
+		vidc.v_cycle = vcr - 2;
+
+	switch (var->bits_per_pixel) {
+	case  1: vidc.control |= VIDC20_CTRL_1BPP;	break;
+	case  2: vidc.control |= VIDC20_CTRL_2BPP;	break;
+	case  4: vidc.control |= VIDC20_CTRL_4BPP;	break;
+	default:
+	case  8: vidc.control |= VIDC20_CTRL_8BPP;	break;
+	case 16: vidc.control |= VIDC20_CTRL_16BPP;	break;
+	case 32: vidc.control |= VIDC20_CTRL_32BPP;	break;
+	}
+
+	acornfb_vidc20_find_rates(&vidc, var);
+	fsize = var->vsync_len + var->upper_margin + var->lower_margin - 1;
+
+	if (memcmp(&current_vidc, &vidc, sizeof(vidc))) {
+		current_vidc = vidc;
+
+		vidc_writel(VIDC20_CTRL | vidc.control);
+		vidc_writel(0xd0000000 | vidc.pll_ctl);
+		vidc_writel(0x80000000 | vidc.h_cycle);
+		vidc_writel(0x81000000 | vidc.h_sync_width);
+		vidc_writel(0x82000000 | vidc.h_border_start);
+		vidc_writel(0x83000000 | vidc.h_display_start);
+		vidc_writel(0x84000000 | vidc.h_display_end);
+		vidc_writel(0x85000000 | vidc.h_border_end);
+		vidc_writel(0x86000000);
+		vidc_writel(0x87000000 | vidc.h_interlace);
+		vidc_writel(0x90000000 | vidc.v_cycle);
+		vidc_writel(0x91000000 | vidc.v_sync_width);
+		vidc_writel(0x92000000 | vidc.v_border_start);
+		vidc_writel(0x93000000 | vidc.v_display_start);
+		vidc_writel(0x94000000 | vidc.v_display_end);
+		vidc_writel(0x95000000 | vidc.v_border_end);
+		vidc_writel(0x96000000);
+		vidc_writel(0x97000000);
+	}
+
+	iomd_writel(fsize, IOMD_FSIZE);
+
+	ext_ctl = acornfb_default_econtrol();
+
+	if (var->sync & FB_SYNC_COMP_HIGH_ACT) /* should be FB_SYNC_COMP */
+		ext_ctl |= VIDC20_ECTL_HS_NCSYNC | VIDC20_ECTL_VS_NCSYNC;
+	else {
+		if (var->sync & FB_SYNC_HOR_HIGH_ACT)
+			ext_ctl |= VIDC20_ECTL_HS_HSYNC;
+		else
+			ext_ctl |= VIDC20_ECTL_HS_NHSYNC;
+
+		if (var->sync & FB_SYNC_VERT_HIGH_ACT)
+			ext_ctl |= VIDC20_ECTL_VS_VSYNC;
+		else
+			ext_ctl |= VIDC20_ECTL_VS_NVSYNC;
+	}
+
+	vidc_writel(VIDC20_ECTL | ext_ctl);
+
+	words_per_line = var->xres * var->bits_per_pixel / 32;
+
+	if (current_par.using_vram && info->fix.smem_len == 2048*1024)
+		words_per_line /= 2;
+
+	/* RiscPC doesn't use the VIDC's VRAM control. */
+	dat_ctl = VIDC20_DCTL_VRAM_DIS | VIDC20_DCTL_SNA | words_per_line;
+
+	/* The data bus width is dependent on both the type
+	 * and amount of video memory.
+	 *     DRAM	32bit low
+	 * 1MB VRAM	32bit
+	 * 2MB VRAM	64bit
+	 */
+	if (current_par.using_vram && current_par.vram_half_sam == 2048)
+		dat_ctl |= VIDC20_DCTL_BUS_D63_0;
+	else
+		dat_ctl |= VIDC20_DCTL_BUS_D31_0;
+
+	vidc_writel(VIDC20_DCTL | dat_ctl);
+
+#ifdef DEBUG_MODE_SELECTION
+	printk(KERN_DEBUG "VIDC registers for %dx%dx%d:\n", var->xres,
+	       var->yres, var->bits_per_pixel);
+	printk(KERN_DEBUG " H-cycle          : %d\n", vidc.h_cycle);
+	printk(KERN_DEBUG " H-sync-width     : %d\n", vidc.h_sync_width);
+	printk(KERN_DEBUG " H-border-start   : %d\n", vidc.h_border_start);
+	printk(KERN_DEBUG " H-display-start  : %d\n", vidc.h_display_start);
+	printk(KERN_DEBUG " H-display-end    : %d\n", vidc.h_display_end);
+	printk(KERN_DEBUG " H-border-end     : %d\n", vidc.h_border_end);
+	printk(KERN_DEBUG " H-interlace      : %d\n", vidc.h_interlace);
+	printk(KERN_DEBUG " V-cycle          : %d\n", vidc.v_cycle);
+	printk(KERN_DEBUG " V-sync-width     : %d\n", vidc.v_sync_width);
+	printk(KERN_DEBUG " V-border-start   : %d\n", vidc.v_border_start);
+	printk(KERN_DEBUG " V-display-start  : %d\n", vidc.v_display_start);
+	printk(KERN_DEBUG " V-display-end    : %d\n", vidc.v_display_end);
+	printk(KERN_DEBUG " V-border-end     : %d\n", vidc.v_border_end);
+	printk(KERN_DEBUG " Ext Ctrl  (C)    : 0x%08X\n", ext_ctl);
+	printk(KERN_DEBUG " PLL Ctrl  (D)    : 0x%08X\n", vidc.pll_ctl);
+	printk(KERN_DEBUG " Ctrl      (E)    : 0x%08X\n", vidc.control);
+	printk(KERN_DEBUG " Data Ctrl (F)    : 0x%08X\n", dat_ctl);
+	printk(KERN_DEBUG " Fsize            : 0x%08X\n", fsize);
+#endif
+}
+
+/*
+ * We have to take note of the VIDC20's 16-bit palette here.
+ * The VIDC20 looks up a 16 bit pixel as follows:
+ *
+ *   bits   111111
+ *          5432109876543210
+ *   red            ++++++++  (8 bits,  7 to 0)
+ *  green       ++++++++      (8 bits, 11 to 4)
+ *   blue   ++++++++          (8 bits, 15 to 8)
+ *
+ * We use a pixel which looks like:
+ *
+ *   bits   111111
+ *          5432109876543210
+ *   red               +++++  (5 bits,  4 to  0)
+ *  green         +++++       (5 bits,  9 to  5)
+ *   blue    +++++            (5 bits, 14 to 10)
+ */
+static int
+acornfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
+		  u_int trans, struct fb_info *info)
+{
+	union palette pal;
+
+	if (regno >= current_par.palette_size)
+		return 1;
+
+	if (regno < 16 && info->fix.visual == FB_VISUAL_DIRECTCOLOR) {
+		u32 pseudo_val;
+
+		pseudo_val  = regno << info->var.red.offset;
+		pseudo_val |= regno << info->var.green.offset;
+		pseudo_val |= regno << info->var.blue.offset;
+
+		((u32 *)info->pseudo_palette)[regno] = pseudo_val;
+	}
+
+	pal.p = 0;
+	pal.vidc20.red   = red >> 8;
+	pal.vidc20.green = green >> 8;
+	pal.vidc20.blue  = blue >> 8;
+
+	current_par.palette[regno] = pal;
+
+	if (info->var.bits_per_pixel == 16) {
+		int i;
+
+		pal.p = 0;
+		vidc_writel(0x10000000);
+		for (i = 0; i < 256; i += 1) {
+			pal.vidc20.red   = current_par.palette[i       & 31].vidc20.red;
+			pal.vidc20.green = current_par.palette[(i >> 1) & 31].vidc20.green;
+			pal.vidc20.blue  = current_par.palette[(i >> 2) & 31].vidc20.blue;
+			vidc_writel(pal.p);
+			/* Palette register pointer auto-increments */
+		}
+	} else {
+		vidc_writel(0x10000000 | regno);
+		vidc_writel(pal.p);
+	}
+
+	return 0;
+}
+#endif
+
+/*
+ * Before selecting the timing parameters, adjust
+ * the resolution to fit the rules.
+ */
+static int
+acornfb_adjust_timing(struct fb_info *info, struct fb_var_screeninfo *var, u_int fontht)
+{
+	u_int font_line_len, sam_size, min_size, size, nr_y;
+
+	/* xres must be even */
+	var->xres = (var->xres + 1) & ~1;
+
+	/*
+	 * We don't allow xres_virtual to differ from xres
+	 */
+	var->xres_virtual = var->xres;
+	var->xoffset = 0;
+
+	if (current_par.using_vram)
+		sam_size = current_par.vram_half_sam * 2;
+	else
+		sam_size = 16;
+
+	/*
+	 * Now, find a value for yres_virtual which allows
+	 * us to do ywrap scrolling.  The value of
+	 * yres_virtual must be such that the end of the
+	 * displayable frame buffer must be aligned with
+	 * the start of a font line.
+	 */
+	font_line_len = var->xres * var->bits_per_pixel * fontht / 8;
+	min_size = var->xres * var->yres * var->bits_per_pixel / 8;
+
+	/*
+	 * If minimum screen size is greater than that we have
+	 * available, reject it.
+	 */
+	if (min_size > info->fix.smem_len)
+		return -EINVAL;
+
+	/* Find int 'y', such that y * fll == s * sam < maxsize
+	 * y = s * sam / fll; s = maxsize / sam
+	 */
+	for (size = info->fix.smem_len;
+	     nr_y = size / font_line_len, min_size <= size;
+	     size -= sam_size) {
+		if (nr_y * font_line_len == size)
+			break;
+	}
+	nr_y *= fontht;
+
+	if (var->accel_flags & FB_ACCELF_TEXT) {
+		if (min_size > size) {
+			/*
+			 * failed, use ypan
+			 */
+			size = info->fix.smem_len;
+			var->yres_virtual = size / (font_line_len / fontht);
+		} else
+			var->yres_virtual = nr_y;
+	} else if (var->yres_virtual > nr_y)
+		var->yres_virtual = nr_y;
+
+	current_par.screen_end = info->fix.smem_start + size;
+
+	/*
+	 * Fix yres & yoffset if needed.
+	 */
+	if (var->yres > var->yres_virtual)
+		var->yres = var->yres_virtual;
+
+	if (var->vmode & FB_VMODE_YWRAP) {
+		if (var->yoffset > var->yres_virtual)
+			var->yoffset = var->yres_virtual;
+	} else {
+		if (var->yoffset + var->yres > var->yres_virtual)
+			var->yoffset = var->yres_virtual - var->yres;
+	}
+
+	/* hsync_len must be even */
+	var->hsync_len = (var->hsync_len + 1) & ~1;
+
+#if defined(HAS_VIDC20)
+	/* left_margin must be even */
+	if (var->left_margin & 1) {
+		var->left_margin += 1;
+		var->right_margin -= 1;
+	}
+
+	/* right_margin must be even */
+	if (var->right_margin & 1)
+		var->right_margin += 1;
+#endif
+
+	if (var->vsync_len < 1)
+		var->vsync_len = 1;
+
+	return 0;
+}
+
+static int
+acornfb_validate_timing(struct fb_var_screeninfo *var,
+			struct fb_monspecs *monspecs)
+{
+	unsigned long hs, vs;
+
+	/*
+	 * hs(Hz) = 10^12 / (pixclock * xtotal)
+	 * vs(Hz) = hs(Hz) / ytotal
+	 *
+	 * No need to do long long divisions or anything
+	 * like that if you factor it correctly
+	 */
+	hs = 1953125000 / var->pixclock;
+	hs = hs * 512 /
+	     (var->xres + var->left_margin + var->right_margin + var->hsync_len);
+	vs = hs /
+	     (var->yres + var->upper_margin + var->lower_margin + var->vsync_len);
+
+	return (vs >= monspecs->vfmin && vs <= monspecs->vfmax &&
+		hs >= monspecs->hfmin && hs <= monspecs->hfmax) ? 0 : -EINVAL;
+}
+
+static inline void
+acornfb_update_dma(struct fb_info *info, struct fb_var_screeninfo *var)
+{
+	u_int off = var->yoffset * info->fix.line_length;
+
+#if defined(HAS_MEMC)
+	memc_write(VDMA_INIT, off >> 2);
+#elif defined(HAS_IOMD)
+	iomd_writel(info->fix.smem_start + off, IOMD_VIDINIT);
+#endif
+}
+
+static int
+acornfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
+{
+	u_int fontht;
+	int err;
+
+	/*
+	 * FIXME: Find the font height
+	 */
+	fontht = 8;
+
+	var->red.msb_right = 0;
+	var->green.msb_right = 0;
+	var->blue.msb_right = 0;
+	var->transp.msb_right = 0;
+
+	switch (var->bits_per_pixel) {
+	case 1:	case 2:	case 4:	case 8:
+		var->red.offset    = 0;
+		var->red.length    = var->bits_per_pixel;
+		var->green         = var->red;
+		var->blue          = var->red;
+		var->transp.offset = 0;
+		var->transp.length = 0;
+		break;
+
+#ifdef HAS_VIDC20
+	case 16:
+		var->red.offset    = 0;
+		var->red.length    = 5;
+		var->green.offset  = 5;
+		var->green.length  = 5;
+		var->blue.offset   = 10;
+		var->blue.length   = 5;
+		var->transp.offset = 15;
+		var->transp.length = 1;
+		break;
+
+	case 32:
+		var->red.offset    = 0;
+		var->red.length    = 8;
+		var->green.offset  = 8;
+		var->green.length  = 8;
+		var->blue.offset   = 16;
+		var->blue.length   = 8;
+		var->transp.offset = 24;
+		var->transp.length = 4;
+		break;
+#endif
+	default:
+		return -EINVAL;
+	}
+
+	/*
+	 * Check to see if the pixel rate is valid.
+	 */
+	if (!acornfb_valid_pixrate(var))
+		return -EINVAL;
+
+	/*
+	 * Validate and adjust the resolution to
+	 * match the video generator hardware.
+	 */
+	err = acornfb_adjust_timing(info, var, fontht);
+	if (err)
+		return err;
+
+	/*
+	 * Validate the timing against the
+	 * monitor hardware.
+	 */
+	return acornfb_validate_timing(var, &info->monspecs);
+}
+
+static int acornfb_set_par(struct fb_info *info)
+{
+	switch (info->var.bits_per_pixel) {
+	case 1:
+		current_par.palette_size = 2;
+		info->fix.visual = FB_VISUAL_MONO10;
+		break;
+	case 2:
+		current_par.palette_size = 4;
+		info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
+		break;
+	case 4:
+		current_par.palette_size = 16;
+		info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
+		break;
+	case 8:
+		current_par.palette_size = VIDC_PALETTE_SIZE;
+		info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
+		break;
+#ifdef HAS_VIDC20
+	case 16:
+		current_par.palette_size = 32;
+		info->fix.visual = FB_VISUAL_DIRECTCOLOR;
+		break;
+	case 32:
+		current_par.palette_size = VIDC_PALETTE_SIZE;
+		info->fix.visual = FB_VISUAL_DIRECTCOLOR;
+		break;
+#endif
+	default:
+		BUG();
+	}
+
+	info->fix.line_length	= (info->var.xres * info->var.bits_per_pixel) / 8;
+
+#if defined(HAS_MEMC)
+	{
+		unsigned long size = info->fix.smem_len - VDMA_XFERSIZE;
+
+		memc_write(VDMA_START, 0);
+		memc_write(VDMA_END, size >> 2);
+	}
+#elif defined(HAS_IOMD)
+	{
+		unsigned long start, size;
+		u_int control;
+
+		start = info->fix.smem_start;
+		size  = current_par.screen_end;
+
+		if (current_par.using_vram) {
+			size -= current_par.vram_half_sam;
+			control = DMA_CR_E | (current_par.vram_half_sam / 256);
+		} else {
+			size -= 16;
+			control = DMA_CR_E | DMA_CR_D | 16;
+		}
+
+		iomd_writel(start,   IOMD_VIDSTART);
+		iomd_writel(size,    IOMD_VIDEND);
+		iomd_writel(control, IOMD_VIDCR);
+	}
+#endif
+
+	acornfb_update_dma(info, &info->var);
+	acornfb_set_timing(info);
+
+	return 0;
+}
+
+static int
+acornfb_pan_display(struct fb_var_screeninfo *var, struct fb_info *info)
+{
+	u_int y_bottom = var->yoffset;
+
+	if (!(var->vmode & FB_VMODE_YWRAP))
+		y_bottom += info->var.yres;
+
+	if (y_bottom > info->var.yres_virtual)
+		return -EINVAL;
+
+	acornfb_update_dma(info, var);
+
+	return 0;
+}
+
+static const struct fb_ops acornfb_ops = {
+	.owner		= THIS_MODULE,
+	FB_DEFAULT_IOMEM_OPS,
+	.fb_check_var	= acornfb_check_var,
+	.fb_set_par	= acornfb_set_par,
+	.fb_setcolreg	= acornfb_setcolreg,
+	.fb_pan_display	= acornfb_pan_display,
+};
+
+/*
+ * Everything after here is initialisation!!!
+ */
+static struct fb_videomode modedb[] = {
+	{	/* 320x256 @ 50Hz */
+		NULL, 50,  320,  256, 125000,  92,  62,  35, 19,  38, 2,
+		FB_SYNC_COMP_HIGH_ACT,
+		FB_VMODE_NONINTERLACED
+	}, {	/* 640x250 @ 50Hz, 15.6 kHz hsync */
+		NULL, 50,  640,  250,  62500, 185, 123,  38, 21,  76, 3,
+		0,
+		FB_VMODE_NONINTERLACED
+	}, {	/* 640x256 @ 50Hz, 15.6 kHz hsync */
+		NULL, 50,  640,  256,  62500, 185, 123,  35, 18,  76, 3,
+		0,
+		FB_VMODE_NONINTERLACED
+	}, {	/* 640x512 @ 50Hz, 26.8 kHz hsync */
+		NULL, 50,  640,  512,  41667, 113,  87,  18,  1,  56, 3,
+		0,
+		FB_VMODE_NONINTERLACED
+	}, {	/* 640x250 @ 70Hz, 31.5 kHz hsync */
+		NULL, 70,  640,  250,  39722,  48,  16, 109, 88,  96, 2,
+		0,
+		FB_VMODE_NONINTERLACED
+	}, {	/* 640x256 @ 70Hz, 31.5 kHz hsync */
+		NULL, 70,  640,  256,  39722,  48,  16, 106, 85,  96, 2,
+		0,
+		FB_VMODE_NONINTERLACED
+	}, {	/* 640x352 @ 70Hz, 31.5 kHz hsync */
+		NULL, 70,  640,  352,  39722,  48,  16,  58, 37,  96, 2,
+		0,
+		FB_VMODE_NONINTERLACED
+	}, {	/* 640x480 @ 60Hz, 31.5 kHz hsync */
+		NULL, 60,  640,  480,  39722,  48,  16,  32, 11,  96, 2,
+		0,
+		FB_VMODE_NONINTERLACED
+	}, {	/* 800x600 @ 56Hz, 35.2 kHz hsync */
+		NULL, 56,  800,  600,  27778, 101,  23,  22,  1, 100, 2,
+		0,
+		FB_VMODE_NONINTERLACED
+	}, {	/* 896x352 @ 60Hz, 21.8 kHz hsync */
+		NULL, 60,  896,  352,  41667,  59,  27,   9,  0, 118, 3,
+		0,
+		FB_VMODE_NONINTERLACED
+	}, {	/* 1024x 768 @ 60Hz, 48.4 kHz hsync */
+		NULL, 60, 1024,  768,  15385, 160,  24,  29,  3, 136, 6,
+		0,
+		FB_VMODE_NONINTERLACED
+	}, {	/* 1280x1024 @ 60Hz, 63.8 kHz hsync */
+		NULL, 60, 1280, 1024,   9090, 186,  96,  38,  1, 160, 3,
+		0,
+		FB_VMODE_NONINTERLACED
+	}
+};
+
+static struct fb_videomode acornfb_default_mode = {
+	.name =		NULL,
+	.refresh =	60,
+	.xres =		640,
+	.yres =		480,
+	.pixclock =	39722,
+	.left_margin =	56,
+	.right_margin =	16,
+	.upper_margin =	34,
+	.lower_margin =	9,
+	.hsync_len =	88,
+	.vsync_len =	2,
+	.sync =		0,
+	.vmode =	FB_VMODE_NONINTERLACED
+};
+
+static void acornfb_init_fbinfo(void)
+{
+	static int first = 1;
+
+	if (!first)
+		return;
+	first = 0;
+
+	fb_info.fbops		= &acornfb_ops;
+	fb_info.flags		= FBINFO_HWACCEL_YPAN;
+	fb_info.pseudo_palette	= current_par.pseudo_palette;
+
+	strcpy(fb_info.fix.id, "Acorn");
+	fb_info.fix.type	= FB_TYPE_PACKED_PIXELS;
+	fb_info.fix.type_aux	= 0;
+	fb_info.fix.xpanstep	= 0;
+	fb_info.fix.ypanstep	= 1;
+	fb_info.fix.ywrapstep	= 1;
+	fb_info.fix.line_length	= 0;
+	fb_info.fix.accel	= FB_ACCEL_NONE;
+
+	/*
+	 * setup initial parameters
+	 */
+	memset(&fb_info.var, 0, sizeof(fb_info.var));
+
+#if defined(HAS_VIDC20)
+	fb_info.var.red.length	   = 8;
+	fb_info.var.transp.length  = 4;
+#endif
+	fb_info.var.green	   = fb_info.var.red;
+	fb_info.var.blue	   = fb_info.var.red;
+	fb_info.var.nonstd	   = 0;
+	fb_info.var.activate	   = FB_ACTIVATE_NOW;
+	fb_info.var.height	   = -1;
+	fb_info.var.width	   = -1;
+	fb_info.var.vmode	   = FB_VMODE_NONINTERLACED;
+	fb_info.var.accel_flags	   = FB_ACCELF_TEXT;
+
+	current_par.dram_size	   = 0;
+	current_par.montype	   = -1;
+	current_par.dpms	   = 0;
+}
+
+/*
+ * setup acornfb options:
+ *
+ *  mon:hmin-hmax:vmin-vmax:dpms:width:height
+ *	Set monitor parameters:
+ *		hmin   = horizontal minimum frequency (Hz)
+ *		hmax   = horizontal maximum frequency (Hz)	(optional)
+ *		vmin   = vertical minimum frequency (Hz)
+ *		vmax   = vertical maximum frequency (Hz)	(optional)
+ *		dpms   = DPMS supported?			(optional)
+ *		width  = width of picture in mm.		(optional)
+ *		height = height of picture in mm.		(optional)
+ *
+ * montype:type
+ *	Set RISC-OS style monitor type:
+ *		0 (or tv)	- TV frequency
+ *		1 (or multi)	- Multi frequency
+ *		2 (or hires)	- Hi-res monochrome
+ *		3 (or vga)	- VGA
+ *		4 (or svga)	- SVGA
+ *		auto, or option missing
+ *				- try hardware detect
+ *
+ * dram:size
+ *	Set the amount of DRAM to use for the frame buffer
+ *	(even if you have VRAM).
+ *	size can optionally be followed by 'M' or 'K' for
+ *	MB or KB respectively.
+ */
+static void acornfb_parse_mon(char *opt)
+{
+	char *p = opt;
+
+	current_par.montype = -2;
+
+	fb_info.monspecs.hfmin = simple_strtoul(p, &p, 0);
+	if (*p == '-')
+		fb_info.monspecs.hfmax = simple_strtoul(p + 1, &p, 0);
+	else
+		fb_info.monspecs.hfmax = fb_info.monspecs.hfmin;
+
+	if (*p != ':')
+		goto bad;
+
+	fb_info.monspecs.vfmin = simple_strtoul(p + 1, &p, 0);
+	if (*p == '-')
+		fb_info.monspecs.vfmax = simple_strtoul(p + 1, &p, 0);
+	else
+		fb_info.monspecs.vfmax = fb_info.monspecs.vfmin;
+
+	if (*p != ':')
+		goto check_values;
+
+	fb_info.monspecs.dpms = simple_strtoul(p + 1, &p, 0);
+
+	if (*p != ':')
+		goto check_values;
+
+	fb_info.var.width = simple_strtoul(p + 1, &p, 0);
+
+	if (*p != ':')
+		goto check_values;
+
+	fb_info.var.height = simple_strtoul(p + 1, NULL, 0);
+
+check_values:
+	if (fb_info.monspecs.hfmax < fb_info.monspecs.hfmin ||
+	    fb_info.monspecs.vfmax < fb_info.monspecs.vfmin)
+		goto bad;
+	return;
+
+bad:
+	printk(KERN_ERR "Acornfb: bad monitor settings: %s\n", opt);
+	current_par.montype = -1;
+}
+
+static void acornfb_parse_montype(char *opt)
+{
+	current_par.montype = -2;
+
+	if (strncmp(opt, "tv", 2) == 0) {
+		opt += 2;
+		current_par.montype = 0;
+	} else if (strncmp(opt, "multi", 5) == 0) {
+		opt += 5;
+		current_par.montype = 1;
+	} else if (strncmp(opt, "hires", 5) == 0) {
+		opt += 5;
+		current_par.montype = 2;
+	} else if (strncmp(opt, "vga", 3) == 0) {
+		opt += 3;
+		current_par.montype = 3;
+	} else if (strncmp(opt, "svga", 4) == 0) {
+		opt += 4;
+		current_par.montype = 4;
+	} else if (strncmp(opt, "auto", 4) == 0) {
+		opt += 4;
+		current_par.montype = -1;
+	} else if (isdigit(*opt))
+		current_par.montype = simple_strtoul(opt, &opt, 0);
+
+	if (current_par.montype == -2 ||
+	    current_par.montype > NR_MONTYPES) {
+		printk(KERN_ERR "acornfb: unknown monitor type: %s\n",
+			opt);
+		current_par.montype = -1;
+	} else
+	if (opt && *opt) {
+		if (strcmp(opt, ",dpms") == 0)
+			current_par.dpms = 1;
+		else
+			printk(KERN_ERR
+			       "acornfb: unknown monitor option: %s\n",
+			       opt);
+	}
+}
+
+static void acornfb_parse_dram(char *opt)
+{
+	unsigned int size;
+
+	size = simple_strtoul(opt, &opt, 0);
+
+	if (opt) {
+		switch (*opt) {
+		case 'M':
+		case 'm':
+			size *= 1024;
+			fallthrough;
+		case 'K':
+		case 'k':
+			size *= 1024;
+		default:
+			break;
+		}
+	}
+
+	current_par.dram_size = size;
+}
+
+static struct options {
+	char *name;
+	void (*parse)(char *opt);
+} opt_table[] = {
+	{ "mon",     acornfb_parse_mon     },
+	{ "montype", acornfb_parse_montype },
+	{ "dram",    acornfb_parse_dram    },
+	{ NULL, NULL }
+};
+
+static int acornfb_setup(char *options)
+{
+	struct options *optp;
+	char *opt;
+
+	if (!options || !*options)
+		return 0;
+
+	acornfb_init_fbinfo();
+
+	while ((opt = strsep(&options, ",")) != NULL) {
+		if (!*opt)
+			continue;
+
+		for (optp = opt_table; optp->name; optp++) {
+			int optlen;
+
+			optlen = strlen(optp->name);
+
+			if (strncmp(opt, optp->name, optlen) == 0 &&
+			    opt[optlen] == ':') {
+				optp->parse(opt + optlen + 1);
+				break;
+			}
+		}
+
+		if (!optp->name)
+			printk(KERN_ERR "acornfb: unknown parameter: %s\n",
+			       opt);
+	}
+	return 0;
+}
+
+/*
+ * Detect type of monitor connected
+ *  For now, we just assume SVGA
+ */
+static int acornfb_detect_monitortype(void)
+{
+	return 4;
+}
+
+static int acornfb_probe(struct platform_device *dev)
+{
+	unsigned long size;
+	u_int h_sync, v_sync;
+	int rc, i;
+	char *option = NULL;
+
+	if (fb_get_options("acornfb", &option))
+		return -ENODEV;
+	acornfb_setup(option);
+
+	acornfb_init_fbinfo();
+
+	current_par.dev = &dev->dev;
+
+	if (current_par.montype == -1)
+		current_par.montype = acornfb_detect_monitortype();
+
+	if (current_par.montype == -1 || current_par.montype > NR_MONTYPES)
+		current_par.montype = 4;
+
+	if (current_par.montype >= 0) {
+		fb_info.monspecs = monspecs[current_par.montype];
+		fb_info.monspecs.dpms = current_par.dpms;
+	}
+
+	/*
+	 * Try to select a suitable default mode
+	 */
+	for (i = 0; i < ARRAY_SIZE(modedb); i++) {
+		unsigned long hs;
+
+		hs = modedb[i].refresh *
+		     (modedb[i].yres + modedb[i].upper_margin +
+		      modedb[i].lower_margin + modedb[i].vsync_len);
+		if (modedb[i].xres == DEFAULT_XRES &&
+		    modedb[i].yres == DEFAULT_YRES &&
+		    modedb[i].refresh >= fb_info.monspecs.vfmin &&
+		    modedb[i].refresh <= fb_info.monspecs.vfmax &&
+		    hs                >= fb_info.monspecs.hfmin &&
+		    hs                <= fb_info.monspecs.hfmax) {
+			acornfb_default_mode = modedb[i];
+			break;
+		}
+	}
+
+	fb_info.screen_base    = (char *)SCREEN_BASE;
+	fb_info.fix.smem_start = SCREEN_START;
+	current_par.using_vram = 0;
+
+	/*
+	 * If vram_size is set, we are using VRAM in
+	 * a Risc PC.  However, if the user has specified
+	 * an amount of DRAM then use that instead.
+	 */
+	if (vram_size && !current_par.dram_size) {
+		size = vram_size;
+		current_par.vram_half_sam = vram_size / 1024;
+		current_par.using_vram = 1;
+	} else if (current_par.dram_size)
+		size = current_par.dram_size;
+	else
+		size = MAX_SIZE;
+
+	/*
+	 * Limit maximum screen size.
+	 */
+	if (size > MAX_SIZE)
+		size = MAX_SIZE;
+
+	size = PAGE_ALIGN(size);
+
+#if defined(HAS_VIDC20)
+	if (!current_par.using_vram) {
+		dma_addr_t handle;
+		void *base;
+
+		/*
+		 * RiscPC needs to allocate the DRAM memory
+		 * for the framebuffer if we are not using
+		 * VRAM.
+		 */
+		base = dma_alloc_wc(current_par.dev, size, &handle,
+				    GFP_KERNEL);
+		if (base == NULL) {
+			printk(KERN_ERR "acornfb: unable to allocate screen memory\n");
+			return -ENOMEM;
+		}
+
+		fb_info.screen_base = base;
+		fb_info.fix.smem_start = handle;
+	}
+#endif
+	fb_info.fix.smem_len = size;
+	current_par.palette_size   = VIDC_PALETTE_SIZE;
+
+	/*
+	 * Lookup the timing for this resolution.  If we can't
+	 * find it, then we can't restore it if we change
+	 * the resolution, so we disable this feature.
+	 */
+	do {
+		rc = fb_find_mode(&fb_info.var, &fb_info, NULL, modedb,
+				 ARRAY_SIZE(modedb),
+				 &acornfb_default_mode, DEFAULT_BPP);
+		/*
+		 * If we found an exact match, all ok.
+		 */
+		if (rc == 1)
+			break;
+
+		rc = fb_find_mode(&fb_info.var, &fb_info, NULL, NULL, 0,
+				  &acornfb_default_mode, DEFAULT_BPP);
+		/*
+		 * If we found an exact match, all ok.
+		 */
+		if (rc == 1)
+			break;
+
+		rc = fb_find_mode(&fb_info.var, &fb_info, NULL, modedb,
+				 ARRAY_SIZE(modedb),
+				 &acornfb_default_mode, DEFAULT_BPP);
+		if (rc)
+			break;
+
+		rc = fb_find_mode(&fb_info.var, &fb_info, NULL, NULL, 0,
+				  &acornfb_default_mode, DEFAULT_BPP);
+	} while (0);
+
+	/*
+	 * If we didn't find an exact match, try the
+	 * generic database.
+	 */
+	if (rc == 0) {
+		printk("Acornfb: no valid mode found\n");
+		return -EINVAL;
+	}
+
+	h_sync = 1953125000 / fb_info.var.pixclock;
+	h_sync = h_sync * 512 / (fb_info.var.xres + fb_info.var.left_margin +
+		 fb_info.var.right_margin + fb_info.var.hsync_len);
+	v_sync = h_sync / (fb_info.var.yres + fb_info.var.upper_margin +
+		 fb_info.var.lower_margin + fb_info.var.vsync_len);
+
+	printk(KERN_INFO "Acornfb: %dkB %cRAM, %s, using %dx%d, %d.%03dkHz, %dHz\n",
+		fb_info.fix.smem_len / 1024,
+		current_par.using_vram ? 'V' : 'D',
+		VIDC_NAME, fb_info.var.xres, fb_info.var.yres,
+		h_sync / 1000, h_sync % 1000, v_sync);
+
+	printk(KERN_INFO "Acornfb: Monitor: %d.%03d-%d.%03dkHz, %d-%dHz%s\n",
+		fb_info.monspecs.hfmin / 1000, fb_info.monspecs.hfmin % 1000,
+		fb_info.monspecs.hfmax / 1000, fb_info.monspecs.hfmax % 1000,
+		fb_info.monspecs.vfmin, fb_info.monspecs.vfmax,
+		fb_info.monspecs.dpms ? ", DPMS" : "");
+
+	if (fb_set_var(&fb_info, &fb_info.var))
+		printk(KERN_ERR "Acornfb: unable to set display parameters\n");
+
+	if (register_framebuffer(&fb_info) < 0)
+		return -EINVAL;
+	return 0;
+}
+
+static struct platform_driver acornfb_driver = {
+	.probe	= acornfb_probe,
+	.driver	= {
+		.name	= "acornfb",
+	},
+};
+
+static int __init acornfb_init(void)
+{
+	return platform_driver_register(&acornfb_driver);
+}
+
+module_init(acornfb_init);
+
+MODULE_AUTHOR("Russell King");
+MODULE_DESCRIPTION("VIDC 1/1a/20 framebuffer driver");
+MODULE_LICENSE("GPL");