[PATCH] Fbdev driver for IBM GXT4500P videocards

This is an fbdev driver for the IBM GXT4500P display card found in some IBM
System P (pSeries) machines.  These cards have hardware 2D and 3D
capabilities, but the driver does not use them; it just exports a dumb
framebuffer.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: James Simmons <jsimmons@infradead.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 752 insertions, 0 deletions

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index ab1daecfeac..4e83f01e894 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -1615,6 +1615,16 @@ config FB_PNX4008_DUM_RGB
 	---help---
 	  Say Y here to enable support for PNX4008 RGB Framebuffer
 
+config FB_IBM_GXT4500
+	tristate "Framebuffer support for IBM GXT4500P adaptor"
+	depends on PPC
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT
+	---help---
+	  Say Y here to enable support for the IBM GXT4500P display
+	  adaptor, found on some IBM System P (pSeries) machines.
+
 config FB_VIRTUAL
 	tristate "Virtual Frame Buffer support (ONLY FOR TESTING!)"
 	depends on FB
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index a6980e9a248..309a26dd164 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -99,6 +99,7 @@ obj-$(CONFIG_FB_IMX)              += imxfb.o
 obj-$(CONFIG_FB_S3C2410)	  += s3c2410fb.o
 obj-$(CONFIG_FB_PNX4008_DUM)	  += pnx4008/
 obj-$(CONFIG_FB_PNX4008_DUM_RGB)  += pnx4008/
+obj-$(CONFIG_FB_IBM_GXT4500)	  += gxt4500.o
 
 # Platform or fallback drivers go here
 obj-$(CONFIG_FB_VESA)             += vesafb.o
diff --git a/drivers/video/gxt4500.c b/drivers/video/gxt4500.c
new file mode 100644
index 00000000000..3adf6ab0768
--- /dev/null
+++ b/drivers/video/gxt4500.c
@@ -0,0 +1,741 @@
+/*
+ * Frame buffer device for IBM GXT4500P display adaptor
+ *
+ * Copyright (C) 2006 Paul Mackerras, IBM Corp. <paulus@samba.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/fb.h>
+#include <linux/console.h>
+#include <linux/pci.h>
+#include <linux/pci_ids.h>
+#include <linux/delay.h>
+
+#define PCI_DEVICE_ID_IBM_GXT4500P	0x21c
+
+/* GXT4500P registers */
+
+/* Registers in PCI config space */
+#define CFG_ENDIAN0		0x40
+
+/* Misc control/status registers */
+#define STATUS			0x1000
+#define CTRL_REG0		0x1004
+#define   CR0_HALT_DMA			0x4
+#define   CR0_RASTER_RESET		0x8
+#define   CR0_GEOM_RESET		0x10
+#define   CR0_MEM_CTRLER_RESET		0x20
+
+/* Framebuffer control registers */
+#define FB_AB_CTRL		0x1100
+#define FB_CD_CTRL		0x1104
+#define FB_WID_CTRL		0x1108
+#define FB_Z_CTRL		0x110c
+#define FB_VGA_CTRL		0x1110
+#define REFRESH_AB_CTRL		0x1114
+#define REFRESH_CD_CTRL		0x1118
+#define FB_OVL_CTRL		0x111c
+#define   FB_CTRL_TYPE			0x80000000
+#define   FB_CTRL_WIDTH_MASK		0x007f0000
+#define   FB_CTRL_WIDTH_SHIFT		16
+#define   FB_CTRL_START_SEG_MASK	0x00003fff
+
+#define REFRESH_START		0x1098
+#define REFRESH_SIZE		0x109c
+
+/* "Direct" framebuffer access registers */
+#define DFA_FB_A		0x11e0
+#define DFA_FB_B		0x11e4
+#define DFA_FB_C		0x11e8
+#define DFA_FB_D		0x11ec
+#define   DFA_FB_ENABLE			0x80000000
+#define   DFA_FB_BASE_MASK		0x03f00000
+#define   DFA_FB_STRIDE_1k		0x00000000
+#define   DFA_FB_STRIDE_2k		0x00000010
+#define   DFA_FB_STRIDE_4k		0x00000020
+#define   DFA_PIX_8BIT			0x00000000
+#define   DFA_PIX_16BIT_565		0x00000001
+#define   DFA_PIX_16BIT_1555		0x00000002
+#define   DFA_PIX_24BIT			0x00000004
+#define   DFA_PIX_32BIT			0x00000005
+
+/* maps DFA_PIX_* to pixel size in bytes */
+static const unsigned char pixsize[] = {
+	1, 2, 2, 2, 4, 4
+};
+
+/* Display timing generator registers */
+#define DTG_CONTROL		0x1900
+#define   DTG_CTL_SCREEN_REFRESH	2
+#define   DTG_CTL_ENABLE		1
+#define DTG_HORIZ_EXTENT	0x1904
+#define DTG_HORIZ_DISPLAY	0x1908
+#define DTG_HSYNC_START		0x190c
+#define DTG_HSYNC_END		0x1910
+#define DTG_HSYNC_END_COMP	0x1914
+#define DTG_VERT_EXTENT		0x1918
+#define DTG_VERT_DISPLAY	0x191c
+#define DTG_VSYNC_START		0x1920
+#define DTG_VSYNC_END		0x1924
+#define DTG_VERT_SHORT		0x1928
+
+/* PLL/RAMDAC registers */
+#define DISP_CTL		0x402c
+#define   DISP_CTL_OFF			2
+#define SYNC_CTL		0x4034
+#define   SYNC_CTL_SYNC_ON_RGB		1
+#define   SYNC_CTL_SYNC_OFF		2
+#define   SYNC_CTL_HSYNC_INV		8
+#define   SYNC_CTL_VSYNC_INV		0x10
+#define   SYNC_CTL_HSYNC_OFF		0x20
+#define   SYNC_CTL_VSYNC_OFF		0x40
+
+#define PLL_M			0x4040
+#define PLL_N			0x4044
+#define PLL_POSTDIV		0x4048
+
+/* Hardware cursor */
+#define CURSOR_X		0x4078
+#define CURSOR_Y		0x407c
+#define CURSOR_HOTSPOT		0x4080
+#define CURSOR_MODE		0x4084
+#define   CURSOR_MODE_OFF		0
+#define   CURSOR_MODE_4BPP		1
+#define CURSOR_PIXMAP		0x5000
+#define CURSOR_CMAP		0x7400
+
+/* Window attribute table */
+#define WAT_FMT			0x4100
+#define   WAT_FMT_24BIT			0
+#define   WAT_FMT_16BIT_565		1
+#define   WAT_FMT_16BIT_1555		2
+#define   WAT_FMT_32BIT			3	/* 0 vs. 3 is a guess */
+#define   WAT_FMT_8BIT_332		9
+#define   WAT_FMT_8BIT			0xa
+#define   WAT_FMT_NO_CMAP		4	/* ORd in to other values */
+#define WAT_CMAP_OFFSET		0x4104		/* 4-bit value gets << 6 */
+#define WAT_CTRL		0x4108
+#define   WAT_CTRL_SEL_B		1	/* select B buffer if 1 */
+#define   WAT_CTRL_NO_INC		2
+#define WAT_GAMMA_CTRL		0x410c
+#define   WAT_GAMMA_DISABLE		1	/* disables gamma cmap */
+#define WAT_OVL_CTRL		0x430c		/* controls overlay */
+
+/* Indexed by DFA_PIX_* values */
+static const unsigned char watfmt[] = {
+	WAT_FMT_8BIT, WAT_FMT_16BIT_565, WAT_FMT_16BIT_1555, 0,
+	WAT_FMT_24BIT, WAT_FMT_32BIT
+};
+
+/* Colormap array; 1k entries of 4 bytes each */
+#define CMAP			0x6000
+
+#define readreg(par, reg)	readl((par)->regs + (reg))
+#define writereg(par, reg, val)	writel((val), (par)->regs + (reg))
+
+struct gxt4500_par {
+	void __iomem *regs;
+
+	int pixfmt;		/* pixel format, see DFA_PIX_* values */
+
+	/* PLL parameters */
+	int pll_m;		/* ref clock divisor */
+	int pll_n;		/* VCO divisor */
+	int pll_pd1;		/* first post-divisor */
+	int pll_pd2;		/* second post-divisor */
+
+	u32 pseudo_palette[16];	/* used in color blits */
+};
+
+/* mode requested by user */
+static char *mode_option;
+
+/* default mode: 1280x1024 @ 60 Hz, 8 bpp */
+static const struct fb_videomode defaultmode __devinitdata = {
+	.refresh = 60,
+	.xres = 1280,
+	.yres = 1024,
+	.pixclock = 9295,
+	.left_margin = 248,
+	.right_margin = 48,
+	.upper_margin = 38,
+	.lower_margin = 1,
+	.hsync_len = 112,
+	.vsync_len = 3,
+	.vmode = FB_VMODE_NONINTERLACED
+};
+
+/*
+ * The refclk and VCO dividers appear to use a linear feedback shift
+ * register, which gets reloaded when it reaches a terminal value, at
+ * which point the divider output is toggled.  Thus one can obtain
+ * whatever divisor is required by putting the appropriate value into
+ * the reload register.  For a divisor of N, one puts the value from
+ * the LFSR sequence that comes N-1 places before the terminal value
+ * into the reload register.
+ */
+
+static const unsigned char mdivtab[] = {
+/* 1 */		      0x3f, 0x00, 0x20, 0x10, 0x28, 0x14, 0x2a, 0x15, 0x0a,
+/* 10 */	0x25, 0x32, 0x19, 0x0c, 0x26, 0x13, 0x09, 0x04, 0x22, 0x11,
+/* 20 */	0x08, 0x24, 0x12, 0x29, 0x34, 0x1a, 0x2d, 0x36, 0x1b, 0x0d,
+/* 30 */	0x06, 0x23, 0x31, 0x38, 0x1c, 0x2e, 0x17, 0x0b, 0x05, 0x02,
+/* 40 */	0x21, 0x30, 0x18, 0x2c, 0x16, 0x2b, 0x35, 0x3a, 0x1d, 0x0e,
+/* 50 */	0x27, 0x33, 0x39, 0x3c, 0x1e, 0x2f, 0x37, 0x3b, 0x3d, 0x3e,
+/* 60 */	0x1f, 0x0f, 0x07, 0x03, 0x01,
+};
+
+static const unsigned char ndivtab[] = {
+/* 2 */		            0x00, 0x80, 0xc0, 0xe0, 0xf0, 0x78, 0xbc, 0x5e,
+/* 10 */	0x2f, 0x17, 0x0b, 0x85, 0xc2, 0xe1, 0x70, 0x38, 0x9c, 0x4e,
+/* 20 */	0xa7, 0xd3, 0xe9, 0xf4, 0xfa, 0xfd, 0xfe, 0x7f, 0xbf, 0xdf,
+/* 30 */	0xef, 0x77, 0x3b, 0x1d, 0x8e, 0xc7, 0xe3, 0x71, 0xb8, 0xdc,
+/* 40 */	0x6e, 0xb7, 0x5b, 0x2d, 0x16, 0x8b, 0xc5, 0xe2, 0xf1, 0xf8,
+/* 50 */	0xfc, 0x7e, 0x3f, 0x9f, 0xcf, 0x67, 0xb3, 0xd9, 0x6c, 0xb6,
+/* 60 */	0xdb, 0x6d, 0x36, 0x9b, 0x4d, 0x26, 0x13, 0x89, 0xc4, 0x62,
+/* 70 */	0xb1, 0xd8, 0xec, 0xf6, 0xfb, 0x7d, 0xbe, 0x5f, 0xaf, 0x57,
+/* 80 */	0x2b, 0x95, 0x4a, 0x25, 0x92, 0x49, 0xa4, 0x52, 0x29, 0x94,
+/* 90 */	0xca, 0x65, 0xb2, 0x59, 0x2c, 0x96, 0xcb, 0xe5, 0xf2, 0x79,
+/* 100 */	0x3c, 0x1e, 0x0f, 0x07, 0x83, 0x41, 0x20, 0x90, 0x48, 0x24,
+/* 110 */	0x12, 0x09, 0x84, 0x42, 0xa1, 0x50, 0x28, 0x14, 0x8a, 0x45,
+/* 120 */	0xa2, 0xd1, 0xe8, 0x74, 0xba, 0xdd, 0xee, 0xf7, 0x7b, 0x3d,
+/* 130 */	0x9e, 0x4f, 0x27, 0x93, 0xc9, 0xe4, 0x72, 0x39, 0x1c, 0x0e,
+/* 140 */	0x87, 0xc3, 0x61, 0x30, 0x18, 0x8c, 0xc6, 0x63, 0x31, 0x98,
+/* 150 */	0xcc, 0xe6, 0x73, 0xb9, 0x5c, 0x2e, 0x97, 0x4b, 0xa5, 0xd2,
+/* 160 */	0x69, 0xb4, 0xda, 0xed, 0x76, 0xbb, 0x5d, 0xae, 0xd7, 0x6b,
+/* 170 */	0xb5, 0x5a, 0xad, 0x56, 0xab, 0xd5, 0x6a, 0x35, 0x1a, 0x8d,
+/* 180 */	0x46, 0x23, 0x11, 0x88, 0x44, 0x22, 0x91, 0xc8, 0x64, 0x32,
+/* 190 */	0x19, 0x0c, 0x86, 0x43, 0x21, 0x10, 0x08, 0x04, 0x02, 0x81,
+/* 200 */	0x40, 0xa0, 0xd0, 0x68, 0x34, 0x9a, 0xcd, 0x66, 0x33, 0x99,
+/* 210 */	0x4c, 0xa6, 0x53, 0xa9, 0xd4, 0xea, 0x75, 0x3a, 0x9d, 0xce,
+/* 220 */	0xe7, 0xf3, 0xf9, 0x7c, 0x3e, 0x1f, 0x8f, 0x47, 0xa3, 0x51,
+/* 230 */	0xa8, 0x54, 0xaa, 0x55, 0x2a, 0x15, 0x0a, 0x05, 0x82, 0xc1,
+/* 240 */	0x60, 0xb0, 0x58, 0xac, 0xd6, 0xeb, 0xf5, 0x7a, 0xbd, 0xde,
+/* 250 */	0x6f, 0x37, 0x1b, 0x0d, 0x06, 0x03, 0x01,
+};
+
+#define REF_PERIOD_PS	9259	/* period of reference clock in ps */
+
+static int calc_pll(int period_ps, struct gxt4500_par *par)
+{
+	int m, n, pdiv1, pdiv2, postdiv;
+	int pll_period, best_error, t;
+
+	/* only deal with range 1MHz - 400MHz */
+	if (period_ps < 2500 || period_ps > 1000000)
+		return -1;
+
+	best_error = 1000000;
+	for (pdiv1 = 1; pdiv1 <= 8; ++pdiv1) {
+		for (pdiv2 = 1; pdiv2 <= pdiv1; ++pdiv2) {
+			postdiv = pdiv1 * pdiv2;
+			pll_period = (period_ps + postdiv - 1) / postdiv;
+			/* keep pll in range 500..1250 MHz */
+			if (pll_period < 800 || pll_period > 2000)
+				continue;
+			for (m = 3; m <= 40; ++m) {
+				n = REF_PERIOD_PS * m * postdiv / period_ps;
+				if (n < 5 || n > 256)
+					continue;
+				t = REF_PERIOD_PS * m * postdiv / n;
+				t -= period_ps;
+				if (t >= 0 && t < best_error) {
+					par->pll_m = m;
+					par->pll_n = n;
+					par->pll_pd1 = pdiv1;
+					par->pll_pd2 = pdiv2;
+					best_error = t;
+				}
+			}
+		}
+	}
+	if (best_error == 1000000)
+		return -1;
+	return 0;
+}
+
+static int calc_pixclock(struct gxt4500_par *par)
+{
+	return REF_PERIOD_PS * par->pll_m * par->pll_pd1 * par->pll_pd2
+		/ par->pll_n;
+}
+
+static int gxt4500_var_to_par(struct fb_var_screeninfo *var,
+			      struct gxt4500_par *par)
+{
+	if (var->xres + var->xoffset > var->xres_virtual ||
+	    var->yres + var->yoffset > var->yres_virtual ||
+	    var->xres_virtual > 4096)
+		return -EINVAL;
+	if ((var->vmode & FB_VMODE_MASK) != FB_VMODE_NONINTERLACED)
+		return -EINVAL;
+
+	if (calc_pll(var->pixclock, par) < 0)
+		return -EINVAL;
+
+	switch (var->bits_per_pixel) {
+	case 32:
+		if (var->transp.length)
+			par->pixfmt = DFA_PIX_32BIT;
+		else
+			par->pixfmt = DFA_PIX_24BIT;
+		break;
+	case 24:
+		par->pixfmt = DFA_PIX_24BIT;
+		break;
+	case 16:
+		if (var->green.length == 5)
+			par->pixfmt = DFA_PIX_16BIT_1555;
+		else
+			par->pixfmt = DFA_PIX_16BIT_565;
+		break;
+	case 8:
+		par->pixfmt = DFA_PIX_8BIT;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct fb_bitfield eightbits = {0, 8};
+static const struct fb_bitfield nobits = {0, 0};
+
+static void gxt4500_unpack_pixfmt(struct fb_var_screeninfo *var,
+				  int pixfmt)
+{
+	var->bits_per_pixel = pixsize[pixfmt] * 8;
+	var->red = eightbits;
+	var->green = eightbits;
+	var->blue = eightbits;
+	var->transp = nobits;
+
+	switch (pixfmt) {
+	case DFA_PIX_16BIT_565:
+		var->red.length = 5;
+		var->green.length = 6;
+		var->blue.length = 5;
+		break;
+	case DFA_PIX_16BIT_1555:
+		var->red.length = 5;
+		var->green.length = 5;
+		var->blue.length = 5;
+		var->transp.length = 1;
+		break;
+	case DFA_PIX_32BIT:
+		var->transp.length = 8;
+		break;
+	}
+	if (pixfmt != DFA_PIX_8BIT) {
+		var->green.offset = var->red.length;
+		var->blue.offset = var->green.offset + var->green.length;
+		if (var->transp.length)
+			var->transp.offset =
+				var->blue.offset + var->blue.length;
+	}
+}
+
+static int gxt4500_check_var(struct fb_var_screeninfo *var,
+			     struct fb_info *info)
+{
+	struct gxt4500_par par;
+	int err;
+
+	par = *(struct gxt4500_par *)info->par;
+	err = gxt4500_var_to_par(var, &par);
+	if (!err) {
+		var->pixclock = calc_pixclock(&par);
+		gxt4500_unpack_pixfmt(var, par.pixfmt);
+	}
+	return err;
+}
+
+static int gxt4500_set_par(struct fb_info *info)
+{
+	struct gxt4500_par *par = info->par;
+	struct fb_var_screeninfo *var = &info->var;
+	int err;
+	u32 ctrlreg;
+	unsigned int dfa_ctl, pixfmt, stride;
+	unsigned int wid_tiles, i;
+	unsigned int prefetch_pix, htot;
+	struct gxt4500_par save_par;
+
+	save_par = *par;
+	err = gxt4500_var_to_par(var, par);
+	if (err) {
+		*par = save_par;
+		return err;
+	}
+
+	/* turn off DTG for now */
+	ctrlreg = readreg(par, DTG_CONTROL);
+	ctrlreg &= ~(DTG_CTL_ENABLE | DTG_CTL_SCREEN_REFRESH);
+	writereg(par, DTG_CONTROL, ctrlreg);
+
+	/* set PLL registers */
+	writereg(par, PLL_M, mdivtab[par->pll_m - 1]);
+	writereg(par, PLL_N, ndivtab[par->pll_n - 2]);
+	writereg(par, PLL_POSTDIV,
+		 ((8 - par->pll_pd1) << 3) | (8 - par->pll_pd2));
+	msleep(20);
+
+	/* turn off hardware cursor */
+	writereg(par, CURSOR_MODE, CURSOR_MODE_OFF);
+
+	/* reset raster engine */
+	writereg(par, CTRL_REG0, CR0_RASTER_RESET | (CR0_RASTER_RESET << 16));
+	udelay(10);
+	writereg(par, CTRL_REG0, CR0_RASTER_RESET << 16);
+
+	/* set display timing generator registers */
+	htot = var->xres + var->left_margin + var->right_margin +
+		var->hsync_len;
+	writereg(par, DTG_HORIZ_EXTENT, htot - 1);
+	writereg(par, DTG_HORIZ_DISPLAY, var->xres - 1);
+	writereg(par, DTG_HSYNC_START, var->xres + var->right_margin - 1);
+	writereg(par, DTG_HSYNC_END,
+		 var->xres + var->right_margin + var->hsync_len - 1);
+	writereg(par, DTG_HSYNC_END_COMP,
+		 var->xres + var->right_margin + var->hsync_len - 1);
+	writereg(par, DTG_VERT_EXTENT,
+		 var->yres + var->upper_margin + var->lower_margin +
+		 var->vsync_len - 1);
+	writereg(par, DTG_VERT_DISPLAY, var->yres - 1);
+	writereg(par, DTG_VSYNC_START, var->yres + var->lower_margin - 1);
+	writereg(par, DTG_VSYNC_END,
+		 var->yres + var->lower_margin + var->vsync_len - 1);
+	prefetch_pix = 3300000 / var->pixclock;
+	if (prefetch_pix >= htot)
+		prefetch_pix = htot - 1;
+	writereg(par, DTG_VERT_SHORT, htot - prefetch_pix - 1);
+	ctrlreg |= DTG_CTL_ENABLE | DTG_CTL_SCREEN_REFRESH;
+	writereg(par, DTG_CONTROL, ctrlreg);
+
+	/* calculate stride in DFA aperture */
+	if (var->xres_virtual > 2048) {
+		stride = 4096;
+		dfa_ctl = DFA_FB_STRIDE_4k;
+	} else if (var->xres_virtual > 1024) {
+		stride = 2048;
+		dfa_ctl = DFA_FB_STRIDE_2k;
+	} else {
+		stride = 1024;
+		dfa_ctl = DFA_FB_STRIDE_1k;
+	}
+
+	/* Set up framebuffer definition */
+	wid_tiles = (var->xres_virtual + 63) >> 6;
+
+	/* XXX add proper FB allocation here someday */
+	writereg(par, FB_AB_CTRL, FB_CTRL_TYPE | (wid_tiles << 16) | 0);
+	writereg(par, REFRESH_AB_CTRL, FB_CTRL_TYPE | (wid_tiles << 16) | 0);
+	writereg(par, FB_CD_CTRL, FB_CTRL_TYPE | (wid_tiles << 16) | 0);
+	writereg(par, REFRESH_CD_CTRL, FB_CTRL_TYPE | (wid_tiles << 16) | 0);
+	writereg(par, REFRESH_START, (var->xoffset << 16) | var->yoffset);
+	writereg(par, REFRESH_SIZE, (var->xres << 16) | var->yres);
+
+	/* Set up framebuffer access by CPU */
+
+	pixfmt = par->pixfmt;
+	dfa_ctl |= DFA_FB_ENABLE | pixfmt;
+	writereg(par, DFA_FB_A, dfa_ctl);
+
+	/*
+	 * Set up window attribute table.
+	 * We set all WAT entries the same so it doesn't matter what the
+	 * window ID (WID) plane contains.
+	 */
+	for (i = 0; i < 32; ++i) {
+		writereg(par, WAT_FMT + (i << 4), watfmt[pixfmt]);
+		writereg(par, WAT_CMAP_OFFSET + (i << 4), 0);
+		writereg(par, WAT_CTRL + (i << 4), 0);
+		writereg(par, WAT_GAMMA_CTRL + (i << 4), WAT_GAMMA_DISABLE);
+	}
+
+	/* Set sync polarity etc. */
+	ctrlreg = readreg(par, SYNC_CTL) &
+		~(SYNC_CTL_SYNC_ON_RGB | SYNC_CTL_HSYNC_INV |
+		  SYNC_CTL_VSYNC_INV);
+	if (var->sync & FB_SYNC_ON_GREEN)
+		ctrlreg |= SYNC_CTL_SYNC_ON_RGB;
+	if (!(var->sync & FB_SYNC_HOR_HIGH_ACT))
+		ctrlreg |= SYNC_CTL_HSYNC_INV;
+	if (!(var->sync & FB_SYNC_VERT_HIGH_ACT))
+		ctrlreg |= SYNC_CTL_VSYNC_INV;
+	writereg(par, SYNC_CTL, ctrlreg);
+
+	info->fix.line_length = stride * pixsize[pixfmt];
+	info->fix.visual = (pixfmt == DFA_PIX_8BIT)? FB_VISUAL_PSEUDOCOLOR:
+		FB_VISUAL_DIRECTCOLOR;
+
+	return 0;
+}
+
+static int gxt4500_setcolreg(unsigned int reg, unsigned int red,
+			     unsigned int green, unsigned int blue,
+			     unsigned int transp, struct fb_info *info)
+{
+	u32 cmap_entry;
+	struct gxt4500_par *par = info->par;
+
+	if (reg > 1023)
+		return 1;
+	cmap_entry = ((transp & 0xff00) << 16) | ((blue & 0xff00) << 8) |
+		(green & 0xff00) | (red >> 8);
+	writereg(par, CMAP + reg * 4, cmap_entry);
+
+	if (reg < 16 && par->pixfmt != DFA_PIX_8BIT) {
+		u32 *pal = info->pseudo_palette;
+		u32 val = reg;
+		switch (par->pixfmt) {
+		case DFA_PIX_16BIT_565:
+			val |= (reg << 11) | (reg << 6);
+			break;
+		case DFA_PIX_16BIT_1555:
+			val |= (reg << 10) | (reg << 5);
+			break;
+		case DFA_PIX_32BIT:
+			val |= (reg << 24);
+			/* fall through */
+		case DFA_PIX_24BIT:
+			val |= (reg << 16) | (reg << 8);
+			break;
+		}
+		pal[reg] = val;
+	}
+
+	return 0;
+}
+
+static int gxt4500_pan_display(struct fb_var_screeninfo *var,
+			       struct fb_info *info)
+{
+	struct gxt4500_par *par = info->par;
+
+	if (var->xoffset & 7)
+		return -EINVAL;
+	if (var->xoffset + var->xres > var->xres_virtual ||
+	    var->yoffset + var->yres > var->yres_virtual)
+		return -EINVAL;
+
+	writereg(par, REFRESH_START, (var->xoffset << 16) | var->yoffset);
+	return 0;
+}
+
+static int gxt4500_blank(int blank, struct fb_info *info)
+{
+	struct gxt4500_par *par = info->par;
+	int ctrl, dctl;
+
+	ctrl = readreg(par, SYNC_CTL);
+	ctrl &= ~(SYNC_CTL_SYNC_OFF | SYNC_CTL_HSYNC_OFF | SYNC_CTL_VSYNC_OFF);
+	dctl = readreg(par, DISP_CTL);
+	dctl |= DISP_CTL_OFF;
+	switch (blank) {
+	case FB_BLANK_UNBLANK:
+		dctl &= ~DISP_CTL_OFF;
+		break;
+	case FB_BLANK_POWERDOWN:
+		ctrl |= SYNC_CTL_SYNC_OFF;
+		break;
+	case FB_BLANK_HSYNC_SUSPEND:
+		ctrl |= SYNC_CTL_HSYNC_OFF;
+		break;
+	case FB_BLANK_VSYNC_SUSPEND:
+		ctrl |= SYNC_CTL_VSYNC_OFF;
+		break;
+	default: ;
+	}
+	writereg(par, SYNC_CTL, ctrl);
+	writereg(par, DISP_CTL, dctl);
+
+	return 0;
+}
+
+static const struct fb_fix_screeninfo gxt4500_fix __devinitdata = {
+	.id = "IBM GXT4500P",
+	.type = FB_TYPE_PACKED_PIXELS,
+	.visual = FB_VISUAL_PSEUDOCOLOR,
+	.xpanstep = 8,
+	.ypanstep = 1,
+	.mmio_len = 0x20000,
+};
+
+static struct fb_ops gxt4500_ops = {
+	.owner = THIS_MODULE,
+	.fb_check_var = gxt4500_check_var,
+	.fb_set_par = gxt4500_set_par,
+	.fb_setcolreg = gxt4500_setcolreg,
+	.fb_pan_display = gxt4500_pan_display,
+	.fb_blank = gxt4500_blank,
+	.fb_fillrect = cfb_fillrect,
+	.fb_copyarea = cfb_copyarea,
+	.fb_imageblit = cfb_imageblit,
+};
+
+/* PCI functions */
+static int __devinit gxt4500_probe(struct pci_dev *pdev,
+				   const struct pci_device_id *ent)
+{
+	int err;
+	unsigned long reg_phys, fb_phys;
+	struct gxt4500_par *par;
+	struct fb_info *info;
+	struct fb_var_screeninfo var;
+
+	err = pci_enable_device(pdev);
+	if (err) {
+		dev_err(&pdev->dev, "gxt4500: cannot enable PCI device: %d\n",
+			err);
+		return err;
+	}
+
+	reg_phys = pci_resource_start(pdev, 0);
+	if (!request_mem_region(reg_phys, pci_resource_len(pdev, 0),
+				"gxt4500 regs")) {
+		dev_err(&pdev->dev, "gxt4500: cannot get registers\n");
+		goto err_nodev;
+	}
+
+	fb_phys = pci_resource_start(pdev, 1);
+	if (!request_mem_region(fb_phys, pci_resource_len(pdev, 1),
+				"gxt4500 FB")) {
+		dev_err(&pdev->dev, "gxt4500: cannot get framebuffer\n");
+		goto err_free_regs;
+	}
+
+	info = framebuffer_alloc(sizeof(struct gxt4500_par), &pdev->dev);
+	if (!info) {
+		dev_err(&pdev->dev, "gxt4500: cannot alloc FB info record");
+		goto err_free_fb;
+	}
+	par = info->par;
+	info->fix = gxt4500_fix;
+	info->pseudo_palette = par->pseudo_palette;
+
+	info->fix.mmio_start = reg_phys;
+	par->regs = ioremap(reg_phys, pci_resource_len(pdev, 0));
+	if (!par->regs) {
+		dev_err(&pdev->dev, "gxt4500: cannot map registers\n");
+		goto err_free_all;
+	}
+
+	info->fix.smem_start = fb_phys;
+	info->fix.smem_len = pci_resource_len(pdev, 1);
+	info->screen_base = ioremap(fb_phys, pci_resource_len(pdev, 1));
+	if (!info->screen_base) {
+		dev_err(&pdev->dev, "gxt4500: cannot map framebuffer\n");
+		goto err_unmap_regs;
+	}
+
+	pci_set_drvdata(pdev, info);
+
+	/* Set byte-swapping for DFA aperture for all pixel sizes */
+	pci_write_config_dword(pdev, CFG_ENDIAN0, 0x333300);
+
+	info->fbops = &gxt4500_ops;
+	info->flags = FBINFO_FLAG_DEFAULT;
+
+	err = fb_alloc_cmap(&info->cmap, 256, 0);
+	if (err) {
+		dev_err(&pdev->dev, "gxt4500: cannot allocate cmap\n");
+		goto err_unmap_all;
+	}
+
+	gxt4500_blank(FB_BLANK_UNBLANK, info);
+
+	if (!fb_find_mode(&var, info, mode_option, NULL, 0, &defaultmode, 8)) {
+		dev_err(&pdev->dev, "gxt4500: cannot find valid video mode\n");
+		goto err_free_cmap;
+	}
+	info->var = var;
+	if (gxt4500_set_par(info)) {
+		printk(KERN_ERR "gxt4500: cannot set video mode\n");
+		goto err_free_cmap;
+	}
+
+	if (register_framebuffer(info) < 0) {
+		dev_err(&pdev->dev, "gxt4500: cannot register framebuffer\n");
+		goto err_free_cmap;
+	}
+	printk(KERN_INFO "fb%d: %s frame buffer device\n",
+	       info->node, info->fix.id);
+
+	return 0;
+
+ err_free_cmap:
+	fb_dealloc_cmap(&info->cmap);
+ err_unmap_all:
+	iounmap(info->screen_base);
+ err_unmap_regs:
+	iounmap(par->regs);
+ err_free_all:
+	framebuffer_release(info);
+ err_free_fb:
+	release_mem_region(fb_phys, pci_resource_len(pdev, 1));
+ err_free_regs:
+	release_mem_region(reg_phys, pci_resource_len(pdev, 0));
+ err_nodev:
+	return -ENODEV;
+}
+
+static void __devexit gxt4500_remove(struct pci_dev *pdev)
+{
+	struct fb_info *info = pci_get_drvdata(pdev);
+	struct gxt4500_par *par;
+
+	if (!info)
+		return;
+	par = info->par;
+	unregister_framebuffer(info);
+	fb_dealloc_cmap(&info->cmap);
+	iounmap(par->regs);
+	iounmap(info->screen_base);
+	release_mem_region(pci_resource_start(pdev, 0),
+			   pci_resource_len(pdev, 0));
+	release_mem_region(pci_resource_start(pdev, 1),
+			   pci_resource_len(pdev, 1));
+	framebuffer_release(info);
+}
+
+/* supported chipsets */
+static const struct pci_device_id gxt4500_pci_tbl[] = {
+	{ PCI_VENDOR_ID_IBM, PCI_DEVICE_ID_IBM_GXT4500P,
+	  PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 },
+	{ 0 }
+};
+
+MODULE_DEVICE_TABLE(pci, gxt4500_pci_tbl);
+
+static struct pci_driver gxt4500_driver = {
+	.name = "gxt4500",
+	.id_table = gxt4500_pci_tbl,
+	.probe = gxt4500_probe,
+	.remove = __devexit_p(gxt4500_remove),
+};
+
+static int __devinit gxt4500_init(void)
+{
+#ifndef MODULE
+	if (fb_get_options("gxt4500", &mode_option))
+		return -ENODEV;
+#endif
+
+	return pci_register_driver(&gxt4500_driver);
+}
+module_init(gxt4500_init);
+
+static void __exit gxt4500_exit(void)
+{
+	pci_unregister_driver(&gxt4500_driver);
+}
+module_exit(gxt4500_exit);
+
+MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
+MODULE_DESCRIPTION("FBDev driver for IBM GXT4500P");
+MODULE_LICENSE("GPL");
+module_param(mode_option, charp, 0);
+MODULE_PARM_DESC(mode_option, "Specify resolution as \"<xres>x<yres>[-<bpp>][@<refresh>]\"");