1 files changed, 650 insertions, 0 deletions

diff --git a/drivers/video/fbdev/aty/mach64_ct.c b/drivers/video/fbdev/aty/mach64_ct.c
new file mode 100644
index 000000000..f87cc81f4
--- /dev/null
+++ b/drivers/video/fbdev/aty/mach64_ct.c
@@ -0,0 +1,650 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ *  ATI Mach64 CT/VT/GT/LT Support
+ */
+
+#include <linux/fb.h>
+#include <linux/delay.h>
+#include <asm/io.h>
+#include <video/mach64.h>
+#include "atyfb.h"
+#ifdef CONFIG_PPC
+#include <asm/machdep.h>
+#endif
+
+#undef DEBUG
+
+static int aty_valid_pll_ct (const struct fb_info *info, u32 vclk_per, struct pll_ct *pll);
+static int aty_dsp_gt       (const struct fb_info *info, u32 bpp, struct pll_ct *pll);
+static int aty_var_to_pll_ct(const struct fb_info *info, u32 vclk_per, u32 bpp, union aty_pll *pll);
+static u32 aty_pll_to_var_ct(const struct fb_info *info, const union aty_pll *pll);
+
+u8 aty_ld_pll_ct(int offset, const struct atyfb_par *par)
+{
+	u8 res;
+
+	/* write addr byte */
+	aty_st_8(CLOCK_CNTL_ADDR, (offset << 2) & PLL_ADDR, par);
+	/* read the register value */
+	res = aty_ld_8(CLOCK_CNTL_DATA, par);
+	return res;
+}
+
+static void aty_st_pll_ct(int offset, u8 val, const struct atyfb_par *par)
+{
+	/* write addr byte */
+	aty_st_8(CLOCK_CNTL_ADDR, ((offset << 2) & PLL_ADDR) | PLL_WR_EN, par);
+	/* write the register value */
+	aty_st_8(CLOCK_CNTL_DATA, val & PLL_DATA, par);
+	aty_st_8(CLOCK_CNTL_ADDR, ((offset << 2) & PLL_ADDR) & ~PLL_WR_EN, par);
+}
+
+/*
+ * by Daniel Mantione
+ *                                  <daniel.mantione@freepascal.org>
+ *
+ *
+ * ATI Mach64 CT clock synthesis description.
+ *
+ * All clocks on the Mach64 can be calculated using the same principle:
+ *
+ *       XTALIN * x * FB_DIV
+ * CLK = ----------------------
+ *       PLL_REF_DIV * POST_DIV
+ *
+ * XTALIN is a fixed speed clock. Common speeds are 14.31 MHz and 29.50 MHz.
+ * PLL_REF_DIV can be set by the user, but is the same for all clocks.
+ * FB_DIV can be set by the user for each clock individually, it should be set
+ * between 128 and 255, the chip will generate a bad clock signal for too low
+ * values.
+ * x depends on the type of clock; usually it is 2, but for the MCLK it can also
+ * be set to 4.
+ * POST_DIV can be set by the user for each clock individually, Possible values
+ * are 1,2,4,8 and for some clocks other values are available too.
+ * CLK is of course the clock speed that is generated.
+ *
+ * The Mach64 has these clocks:
+ *
+ * MCLK			The clock rate of the chip
+ * XCLK			The clock rate of the on-chip memory
+ * VCLK0		First pixel clock of first CRT controller
+ * VCLK1    Second pixel clock of first CRT controller
+ * VCLK2		Third pixel clock of first CRT controller
+ * VCLK3    Fourth pixel clock of first CRT controller
+ * VCLK			Selected pixel clock, one of VCLK0, VCLK1, VCLK2, VCLK3
+ * V2CLK		Pixel clock of the second CRT controller.
+ * SCLK			Multi-purpose clock
+ *
+ * - MCLK and XCLK use the same FB_DIV
+ * - VCLK0 .. VCLK3 use the same FB_DIV
+ * - V2CLK is needed when the second CRTC is used (can be used for dualhead);
+ *   i.e. CRT monitor connected to laptop has different resolution than built
+ *   in LCD monitor.
+ * - SCLK is not available on all cards; it is know to exist on the Rage LT-PRO,
+ *   Rage XL and Rage Mobility. It is know not to exist on the Mach64 VT.
+ * - V2CLK is not available on all cards, most likely only the Rage LT-PRO,
+ *   the Rage XL and the Rage Mobility
+ *
+ * SCLK can be used to:
+ * - Clock the chip instead of MCLK
+ * - Replace XTALIN with a user defined frequency
+ * - Generate the pixel clock for the LCD monitor (instead of VCLK)
+ */
+
+ /*
+  * It can be quite hard to calculate XCLK and MCLK if they don't run at the
+  * same frequency. Luckily, until now all cards that need asynchrone clock
+  * speeds seem to have SCLK.
+  * So this driver uses SCLK to clock the chip and XCLK to clock the memory.
+  */
+
+/* ------------------------------------------------------------------------- */
+
+/*
+ *  PLL programming (Mach64 CT family)
+ *
+ *
+ * This procedure sets the display fifo. The display fifo is a buffer that
+ * contains data read from the video memory that waits to be processed by
+ * the CRT controller.
+ *
+ * On the more modern Mach64 variants, the chip doesn't calculate the
+ * interval after which the display fifo has to be reloaded from memory
+ * automatically, the driver has to do it instead.
+ */
+
+#define Maximum_DSP_PRECISION 7
+const u8 aty_postdividers[8] = {1,2,4,8,3,5,6,12};
+
+static int aty_dsp_gt(const struct fb_info *info, u32 bpp, struct pll_ct *pll)
+{
+	u32 dsp_off, dsp_on, dsp_xclks;
+	u32 multiplier, divider, ras_multiplier, ras_divider, tmp;
+	u8 vshift, xshift;
+	s8 dsp_precision;
+
+	multiplier = ((u32)pll->mclk_fb_div) * pll->vclk_post_div_real;
+	divider = ((u32)pll->vclk_fb_div) * pll->xclk_ref_div;
+
+	ras_multiplier = pll->xclkmaxrasdelay;
+	ras_divider = 1;
+
+	if (bpp>=8)
+		divider = divider * (bpp >> 2);
+
+	vshift = (6 - 2) - pll->xclk_post_div;	/* FIFO is 64 bits wide in accelerator mode ... */
+
+	if (bpp == 0)
+		vshift--;	/* ... but only 32 bits in VGA mode. */
+
+#ifdef CONFIG_FB_ATY_GENERIC_LCD
+	if (pll->xres != 0) {
+		struct atyfb_par *par = (struct atyfb_par *) info->par;
+
+		multiplier = multiplier * par->lcd_width;
+		divider = divider * pll->xres & ~7;
+
+		ras_multiplier = ras_multiplier * par->lcd_width;
+		ras_divider = ras_divider * pll->xres & ~7;
+	}
+#endif
+	/* If we don't do this, 32 bits for multiplier & divider won't be
+	enough in certain situations! */
+	while (((multiplier | divider) & 1) == 0) {
+		multiplier = multiplier >> 1;
+		divider = divider >> 1;
+	}
+
+	/* Determine DSP precision first */
+	tmp = ((multiplier * pll->fifo_size) << vshift) / divider;
+
+	for (dsp_precision = -5;  tmp;  dsp_precision++)
+		tmp >>= 1;
+	if (dsp_precision < 0)
+		dsp_precision = 0;
+	else if (dsp_precision > Maximum_DSP_PRECISION)
+		dsp_precision = Maximum_DSP_PRECISION;
+
+	xshift = 6 - dsp_precision;
+	vshift += xshift;
+
+	/* Move on to dsp_off */
+	dsp_off = ((multiplier * (pll->fifo_size - 1)) << vshift) / divider -
+		(1 << (vshift - xshift));
+
+/*    if (bpp == 0)
+        dsp_on = ((multiplier * 20 << vshift) + divider) / divider;
+    else */
+	{
+		dsp_on = ((multiplier << vshift) + divider) / divider;
+		tmp = ((ras_multiplier << xshift) + ras_divider) / ras_divider;
+		if (dsp_on < tmp)
+			dsp_on = tmp;
+		dsp_on = dsp_on + (tmp * 2) + (pll->xclkpagefaultdelay << xshift);
+	}
+
+	/* Calculate rounding factor and apply it to dsp_on */
+	tmp = ((1 << (Maximum_DSP_PRECISION - dsp_precision)) - 1) >> 1;
+	dsp_on = ((dsp_on + tmp) / (tmp + 1)) * (tmp + 1);
+
+	if (dsp_on >= ((dsp_off / (tmp + 1)) * (tmp + 1))) {
+		dsp_on = dsp_off - (multiplier << vshift) / divider;
+		dsp_on = (dsp_on / (tmp + 1)) * (tmp + 1);
+	}
+
+	/* Last but not least:  dsp_xclks */
+	dsp_xclks = ((multiplier << (vshift + 5)) + divider) / divider;
+
+	/* Get register values. */
+	pll->dsp_on_off = (dsp_on << 16) + dsp_off;
+	pll->dsp_config = (dsp_precision << 20) | (pll->dsp_loop_latency << 16) | dsp_xclks;
+#ifdef DEBUG
+	printk("atyfb(%s): dsp_config 0x%08x, dsp_on_off 0x%08x\n",
+		__func__, pll->dsp_config, pll->dsp_on_off);
+#endif
+	return 0;
+}
+
+static int aty_valid_pll_ct(const struct fb_info *info, u32 vclk_per, struct pll_ct *pll)
+{
+	u32 q;
+	struct atyfb_par *par = (struct atyfb_par *) info->par;
+	int pllvclk;
+
+	/* FIXME: use the VTB/GTB /{3,6,12} post dividers if they're better suited */
+	q = par->ref_clk_per * pll->pll_ref_div * 4 / vclk_per;
+	if (q < 16*8 || q > 255*8) {
+		printk(KERN_CRIT "atyfb: vclk out of range\n");
+		return -EINVAL;
+	} else {
+		pll->vclk_post_div  = (q < 128*8);
+		pll->vclk_post_div += (q <  64*8);
+		pll->vclk_post_div += (q <  32*8);
+	}
+	pll->vclk_post_div_real = aty_postdividers[pll->vclk_post_div];
+	//    pll->vclk_post_div <<= 6;
+	pll->vclk_fb_div = q * pll->vclk_post_div_real / 8;
+	pllvclk = (1000000 * 2 * pll->vclk_fb_div) /
+		(par->ref_clk_per * pll->pll_ref_div);
+#ifdef DEBUG
+	printk("atyfb(%s): pllvclk=%d MHz, vclk=%d MHz\n",
+		__func__, pllvclk, pllvclk / pll->vclk_post_div_real);
+#endif
+	pll->pll_vclk_cntl = 0x03; /* VCLK = PLL_VCLK/VCLKx_POST */
+
+	/* Set ECP (scaler/overlay clock) divider */
+	if (par->pll_limits.ecp_max) {
+		int ecp = pllvclk / pll->vclk_post_div_real;
+		int ecp_div = 0;
+
+		while (ecp > par->pll_limits.ecp_max && ecp_div < 2) {
+			ecp >>= 1;
+			ecp_div++;
+		}
+		pll->pll_vclk_cntl |= ecp_div << 4;
+	}
+
+	return 0;
+}
+
+static int aty_var_to_pll_ct(const struct fb_info *info, u32 vclk_per, u32 bpp, union aty_pll *pll)
+{
+	struct atyfb_par *par = (struct atyfb_par *) info->par;
+	int err;
+
+	if ((err = aty_valid_pll_ct(info, vclk_per, &pll->ct)))
+		return err;
+	if (M64_HAS(GTB_DSP) && (err = aty_dsp_gt(info, bpp, &pll->ct)))
+		return err;
+	/*aty_calc_pll_ct(info, &pll->ct);*/
+	return 0;
+}
+
+static u32 aty_pll_to_var_ct(const struct fb_info *info, const union aty_pll *pll)
+{
+	struct atyfb_par *par = (struct atyfb_par *) info->par;
+	u32 ret;
+	ret = par->ref_clk_per * pll->ct.pll_ref_div * pll->ct.vclk_post_div_real / pll->ct.vclk_fb_div / 2;
+#ifdef CONFIG_FB_ATY_GENERIC_LCD
+	if(pll->ct.xres > 0) {
+		ret *= par->lcd_width;
+		ret /= pll->ct.xres;
+	}
+#endif
+#ifdef DEBUG
+	printk("atyfb(%s): calculated 0x%08X(%i)\n", __func__, ret, ret);
+#endif
+	return ret;
+}
+
+void aty_set_pll_ct(const struct fb_info *info, const union aty_pll *pll)
+{
+	struct atyfb_par *par = (struct atyfb_par *) info->par;
+	u32 crtc_gen_cntl, lcd_gen_cntrl;
+	u8 tmp, tmp2;
+
+	lcd_gen_cntrl = 0;
+#ifdef DEBUG
+	printk("atyfb(%s): about to program:\n"
+		"pll_ext_cntl=0x%02x pll_gen_cntl=0x%02x pll_vclk_cntl=0x%02x\n",
+		__func__,
+		pll->ct.pll_ext_cntl, pll->ct.pll_gen_cntl, pll->ct.pll_vclk_cntl);
+
+	printk("atyfb(%s): setting clock %lu for FeedBackDivider %i, ReferenceDivider %i, PostDivider %i(%i)\n",
+		__func__,
+		par->clk_wr_offset, pll->ct.vclk_fb_div,
+		pll->ct.pll_ref_div, pll->ct.vclk_post_div, pll->ct.vclk_post_div_real);
+#endif
+#ifdef CONFIG_FB_ATY_GENERIC_LCD
+	if (par->lcd_table != 0) {
+		/* turn off LCD */
+		lcd_gen_cntrl = aty_ld_lcd(LCD_GEN_CNTL, par);
+		aty_st_lcd(LCD_GEN_CNTL, lcd_gen_cntrl & ~LCD_ON, par);
+	}
+#endif
+	aty_st_8(CLOCK_CNTL, par->clk_wr_offset | CLOCK_STROBE, par);
+
+	/* Temporarily switch to accelerator mode */
+	crtc_gen_cntl = aty_ld_le32(CRTC_GEN_CNTL, par);
+	if (!(crtc_gen_cntl & CRTC_EXT_DISP_EN))
+		aty_st_le32(CRTC_GEN_CNTL, crtc_gen_cntl | CRTC_EXT_DISP_EN, par);
+
+	/* Reset VCLK generator */
+	aty_st_pll_ct(PLL_VCLK_CNTL, pll->ct.pll_vclk_cntl, par);
+
+	/* Set post-divider */
+	tmp2 = par->clk_wr_offset << 1;
+	tmp = aty_ld_pll_ct(VCLK_POST_DIV, par);
+	tmp &= ~(0x03U << tmp2);
+	tmp |= ((pll->ct.vclk_post_div & 0x03U) << tmp2);
+	aty_st_pll_ct(VCLK_POST_DIV, tmp, par);
+
+	/* Set extended post-divider */
+	tmp = aty_ld_pll_ct(PLL_EXT_CNTL, par);
+	tmp &= ~(0x10U << par->clk_wr_offset);
+	tmp &= 0xF0U;
+	tmp |= pll->ct.pll_ext_cntl;
+	aty_st_pll_ct(PLL_EXT_CNTL, tmp, par);
+
+	/* Set feedback divider */
+	tmp = VCLK0_FB_DIV + par->clk_wr_offset;
+	aty_st_pll_ct(tmp, (pll->ct.vclk_fb_div & 0xFFU), par);
+
+	aty_st_pll_ct(PLL_GEN_CNTL, (pll->ct.pll_gen_cntl & (~(PLL_OVERRIDE | PLL_MCLK_RST))) | OSC_EN, par);
+
+	/* End VCLK generator reset */
+	aty_st_pll_ct(PLL_VCLK_CNTL, pll->ct.pll_vclk_cntl & ~(PLL_VCLK_RST), par);
+	mdelay(5);
+
+	aty_st_pll_ct(PLL_GEN_CNTL, pll->ct.pll_gen_cntl, par);
+	aty_st_pll_ct(PLL_VCLK_CNTL, pll->ct.pll_vclk_cntl, par);
+	mdelay(1);
+
+	/* Restore mode register */
+	if (!(crtc_gen_cntl & CRTC_EXT_DISP_EN))
+		aty_st_le32(CRTC_GEN_CNTL, crtc_gen_cntl, par);
+
+	if (M64_HAS(GTB_DSP)) {
+		u8 dll_cntl;
+
+		if (M64_HAS(XL_DLL))
+			dll_cntl = 0x80;
+		else if (par->ram_type >= SDRAM)
+			dll_cntl = 0xa6;
+		else
+			dll_cntl = 0xa0;
+		aty_st_pll_ct(DLL_CNTL, dll_cntl, par);
+		aty_st_pll_ct(VFC_CNTL, 0x1b, par);
+		aty_st_le32(DSP_CONFIG, pll->ct.dsp_config, par);
+		aty_st_le32(DSP_ON_OFF, pll->ct.dsp_on_off, par);
+
+		mdelay(10);
+		aty_st_pll_ct(DLL_CNTL, dll_cntl, par);
+		mdelay(10);
+		aty_st_pll_ct(DLL_CNTL, dll_cntl | 0x40, par);
+		mdelay(10);
+		aty_st_pll_ct(DLL_CNTL, dll_cntl & ~0x40, par);
+	}
+#ifdef CONFIG_FB_ATY_GENERIC_LCD
+	if (par->lcd_table != 0) {
+		/* restore LCD */
+		aty_st_lcd(LCD_GEN_CNTL, lcd_gen_cntrl, par);
+	}
+#endif
+}
+
+static void aty_get_pll_ct(const struct fb_info *info, union aty_pll *pll)
+{
+	struct atyfb_par *par = (struct atyfb_par *) info->par;
+	u8 tmp, clock;
+
+	clock = aty_ld_8(CLOCK_CNTL, par) & 0x03U;
+	tmp = clock << 1;
+	pll->ct.vclk_post_div = (aty_ld_pll_ct(VCLK_POST_DIV, par) >> tmp) & 0x03U;
+
+	pll->ct.pll_ext_cntl = aty_ld_pll_ct(PLL_EXT_CNTL, par) & 0x0FU;
+	pll->ct.vclk_fb_div = aty_ld_pll_ct(VCLK0_FB_DIV + clock, par) & 0xFFU;
+	pll->ct.pll_ref_div = aty_ld_pll_ct(PLL_REF_DIV, par);
+	pll->ct.mclk_fb_div = aty_ld_pll_ct(MCLK_FB_DIV, par);
+
+	pll->ct.pll_gen_cntl = aty_ld_pll_ct(PLL_GEN_CNTL, par);
+	pll->ct.pll_vclk_cntl = aty_ld_pll_ct(PLL_VCLK_CNTL, par);
+
+	if (M64_HAS(GTB_DSP)) {
+		pll->ct.dsp_config = aty_ld_le32(DSP_CONFIG, par);
+		pll->ct.dsp_on_off = aty_ld_le32(DSP_ON_OFF, par);
+	}
+}
+
+static int aty_init_pll_ct(const struct fb_info *info, union aty_pll *pll)
+{
+	struct atyfb_par *par = (struct atyfb_par *) info->par;
+	u8 mpost_div, xpost_div, sclk_post_div_real;
+	u32 q, memcntl, trp;
+	u32 dsp_config, dsp_on_off, vga_dsp_config, vga_dsp_on_off;
+#ifdef DEBUG
+	int pllmclk, pllsclk;
+#endif
+	pll->ct.pll_ext_cntl = aty_ld_pll_ct(PLL_EXT_CNTL, par);
+	pll->ct.xclk_post_div = pll->ct.pll_ext_cntl & 0x07;
+	pll->ct.xclk_ref_div = 1;
+	switch (pll->ct.xclk_post_div) {
+	case 0:  case 1:  case 2:  case 3:
+		break;
+
+	case 4:
+		pll->ct.xclk_ref_div = 3;
+		pll->ct.xclk_post_div = 0;
+		break;
+
+	default:
+		printk(KERN_CRIT "atyfb: Unsupported xclk source:  %d.\n", pll->ct.xclk_post_div);
+		return -EINVAL;
+	}
+	pll->ct.mclk_fb_mult = 2;
+	if(pll->ct.pll_ext_cntl & PLL_MFB_TIMES_4_2B) {
+		pll->ct.mclk_fb_mult = 4;
+		pll->ct.xclk_post_div -= 1;
+	}
+
+#ifdef DEBUG
+	printk("atyfb(%s): mclk_fb_mult=%d, xclk_post_div=%d\n",
+		__func__, pll->ct.mclk_fb_mult, pll->ct.xclk_post_div);
+#endif
+
+	memcntl = aty_ld_le32(MEM_CNTL, par);
+	trp = (memcntl & 0x300) >> 8;
+
+	pll->ct.xclkpagefaultdelay = ((memcntl & 0xc00) >> 10) + ((memcntl & 0x1000) >> 12) + trp + 2;
+	pll->ct.xclkmaxrasdelay = ((memcntl & 0x70000) >> 16) + trp + 2;
+
+	if (M64_HAS(FIFO_32)) {
+		pll->ct.fifo_size = 32;
+	} else {
+		pll->ct.fifo_size = 24;
+		pll->ct.xclkpagefaultdelay += 2;
+		pll->ct.xclkmaxrasdelay += 3;
+	}
+
+	switch (par->ram_type) {
+	case DRAM:
+		if (info->fix.smem_len<=ONE_MB) {
+			pll->ct.dsp_loop_latency = 10;
+		} else {
+			pll->ct.dsp_loop_latency = 8;
+			pll->ct.xclkpagefaultdelay += 2;
+		}
+		break;
+	case EDO:
+	case PSEUDO_EDO:
+		if (info->fix.smem_len<=ONE_MB) {
+			pll->ct.dsp_loop_latency = 9;
+		} else {
+			pll->ct.dsp_loop_latency = 8;
+			pll->ct.xclkpagefaultdelay += 1;
+		}
+		break;
+	case SDRAM:
+		if (info->fix.smem_len<=ONE_MB) {
+			pll->ct.dsp_loop_latency = 11;
+		} else {
+			pll->ct.dsp_loop_latency = 10;
+			pll->ct.xclkpagefaultdelay += 1;
+		}
+		break;
+	case SGRAM:
+		pll->ct.dsp_loop_latency = 8;
+		pll->ct.xclkpagefaultdelay += 3;
+		break;
+	default:
+		pll->ct.dsp_loop_latency = 11;
+		pll->ct.xclkpagefaultdelay += 3;
+		break;
+	}
+
+	if (pll->ct.xclkmaxrasdelay <= pll->ct.xclkpagefaultdelay)
+		pll->ct.xclkmaxrasdelay = pll->ct.xclkpagefaultdelay + 1;
+
+	/* Allow BIOS to override */
+	dsp_config = aty_ld_le32(DSP_CONFIG, par);
+	dsp_on_off = aty_ld_le32(DSP_ON_OFF, par);
+	vga_dsp_config = aty_ld_le32(VGA_DSP_CONFIG, par);
+	vga_dsp_on_off = aty_ld_le32(VGA_DSP_ON_OFF, par);
+
+	if (dsp_config)
+		pll->ct.dsp_loop_latency = (dsp_config & DSP_LOOP_LATENCY) >> 16;
+#if 0
+	FIXME: is it relevant for us?
+	if ((!dsp_on_off && !M64_HAS(RESET_3D)) ||
+		((dsp_on_off == vga_dsp_on_off) &&
+		(!dsp_config || !((dsp_config ^ vga_dsp_config) & DSP_XCLKS_PER_QW)))) {
+		vga_dsp_on_off &= VGA_DSP_OFF;
+		vga_dsp_config &= VGA_DSP_XCLKS_PER_QW;
+		if (ATIDivide(vga_dsp_on_off, vga_dsp_config, 5, 1) > 24)
+			pll->ct.fifo_size = 32;
+		else
+			pll->ct.fifo_size = 24;
+	}
+#endif
+	/* Exit if the user does not want us to tamper with the clock
+	rates of her chip. */
+	if (par->mclk_per == 0) {
+		u8 mclk_fb_div, pll_ext_cntl;
+		pll->ct.pll_ref_div = aty_ld_pll_ct(PLL_REF_DIV, par);
+		pll_ext_cntl = aty_ld_pll_ct(PLL_EXT_CNTL, par);
+		pll->ct.xclk_post_div_real = aty_postdividers[pll_ext_cntl & 0x07];
+		mclk_fb_div = aty_ld_pll_ct(MCLK_FB_DIV, par);
+		if (pll_ext_cntl & PLL_MFB_TIMES_4_2B)
+			mclk_fb_div <<= 1;
+		pll->ct.mclk_fb_div = mclk_fb_div;
+		return 0;
+	}
+
+	pll->ct.pll_ref_div = par->pll_per * 2 * 255 / par->ref_clk_per;
+
+	/* FIXME: use the VTB/GTB /3 post divider if it's better suited */
+	q = par->ref_clk_per * pll->ct.pll_ref_div * 8 /
+		(pll->ct.mclk_fb_mult * par->xclk_per);
+
+	if (q < 16*8 || q > 255*8) {
+		printk(KERN_CRIT "atxfb: xclk out of range\n");
+		return -EINVAL;
+	} else {
+		xpost_div  = (q < 128*8);
+		xpost_div += (q <  64*8);
+		xpost_div += (q <  32*8);
+	}
+	pll->ct.xclk_post_div_real = aty_postdividers[xpost_div];
+	pll->ct.mclk_fb_div = q * pll->ct.xclk_post_div_real / 8;
+
+#ifdef CONFIG_PPC
+	if (machine_is(powermac)) {
+		/* Override PLL_EXT_CNTL & 0x07. */
+		pll->ct.xclk_post_div = xpost_div;
+		pll->ct.xclk_ref_div = 1;
+	}
+#endif
+
+#ifdef DEBUG
+	pllmclk = (1000000 * pll->ct.mclk_fb_mult * pll->ct.mclk_fb_div) /
+			(par->ref_clk_per * pll->ct.pll_ref_div);
+	printk("atyfb(%s): pllmclk=%d MHz, xclk=%d MHz\n",
+		__func__, pllmclk, pllmclk / pll->ct.xclk_post_div_real);
+#endif
+
+	if (M64_HAS(SDRAM_MAGIC_PLL) && (par->ram_type >= SDRAM))
+		pll->ct.pll_gen_cntl = OSC_EN;
+	else
+		pll->ct.pll_gen_cntl = OSC_EN | DLL_PWDN /* | FORCE_DCLK_TRI_STATE */;
+
+	if (M64_HAS(MAGIC_POSTDIV))
+		pll->ct.pll_ext_cntl = 0;
+	else
+		pll->ct.pll_ext_cntl = xpost_div;
+
+	if (pll->ct.mclk_fb_mult == 4)
+		pll->ct.pll_ext_cntl |= PLL_MFB_TIMES_4_2B;
+
+	if (par->mclk_per == par->xclk_per) {
+		pll->ct.pll_gen_cntl |= (xpost_div << 4); /* mclk == xclk */
+	} else {
+		/*
+		* The chip clock is not equal to the memory clock.
+		* Therefore we will use sclk to clock the chip.
+		*/
+		pll->ct.pll_gen_cntl |= (6 << 4); /* mclk == sclk */
+
+		q = par->ref_clk_per * pll->ct.pll_ref_div * 4 / par->mclk_per;
+		if (q < 16*8 || q > 255*8) {
+			printk(KERN_CRIT "atyfb: mclk out of range\n");
+			return -EINVAL;
+		} else {
+			mpost_div  = (q < 128*8);
+			mpost_div += (q <  64*8);
+			mpost_div += (q <  32*8);
+		}
+		sclk_post_div_real = aty_postdividers[mpost_div];
+		pll->ct.sclk_fb_div = q * sclk_post_div_real / 8;
+		pll->ct.spll_cntl2 = mpost_div << 4;
+#ifdef DEBUG
+		pllsclk = (1000000 * 2 * pll->ct.sclk_fb_div) /
+			(par->ref_clk_per * pll->ct.pll_ref_div);
+		printk("atyfb(%s): use sclk, pllsclk=%d MHz, sclk=mclk=%d MHz\n",
+			__func__, pllsclk, pllsclk / sclk_post_div_real);
+#endif
+	}
+
+	/* Disable the extra precision pixel clock controls since we do not use them. */
+	pll->ct.ext_vpll_cntl = aty_ld_pll_ct(EXT_VPLL_CNTL, par);
+	pll->ct.ext_vpll_cntl &= ~(EXT_VPLL_EN | EXT_VPLL_VGA_EN | EXT_VPLL_INSYNC);
+
+	return 0;
+}
+
+static void aty_resume_pll_ct(const struct fb_info *info,
+			      union aty_pll *pll)
+{
+	struct atyfb_par *par = info->par;
+
+	if (par->mclk_per != par->xclk_per) {
+		/*
+		* This disables the sclk, crashes the computer as reported:
+		* aty_st_pll_ct(SPLL_CNTL2, 3, info);
+		*
+		* So it seems the sclk must be enabled before it is used;
+		* so PLL_GEN_CNTL must be programmed *after* the sclk.
+		*/
+		aty_st_pll_ct(SCLK_FB_DIV, pll->ct.sclk_fb_div, par);
+		aty_st_pll_ct(SPLL_CNTL2, pll->ct.spll_cntl2, par);
+		/*
+		 * SCLK has been started. Wait for the PLL to lock. 5 ms
+		 * should be enough according to mach64 programmer's guide.
+		 */
+		mdelay(5);
+	}
+
+	aty_st_pll_ct(PLL_REF_DIV, pll->ct.pll_ref_div, par);
+	aty_st_pll_ct(PLL_GEN_CNTL, pll->ct.pll_gen_cntl, par);
+	aty_st_pll_ct(MCLK_FB_DIV, pll->ct.mclk_fb_div, par);
+	aty_st_pll_ct(PLL_EXT_CNTL, pll->ct.pll_ext_cntl, par);
+	aty_st_pll_ct(EXT_VPLL_CNTL, pll->ct.ext_vpll_cntl, par);
+}
+
+static int dummy(void)
+{
+	return 0;
+}
+
+const struct aty_dac_ops aty_dac_ct = {
+	.set_dac	= (void *) dummy,
+};
+
+const struct aty_pll_ops aty_pll_ct = {
+	.var_to_pll	= aty_var_to_pll_ct,
+	.pll_to_var	= aty_pll_to_var_ct,
+	.set_pll	= aty_set_pll_ct,
+	.get_pll	= aty_get_pll_ct,
+	.init_pll	= aty_init_pll_ct,
+	.resume_pll	= aty_resume_pll_ct,
+};