drm/mgag200: Add support for G200 desktop cards

This patch adds support for G200 desktop cards. We can reuse the whole
memory and modesetting code. A few PCI and DAC register values have to
be updated accordingly.

The most significant change is in the PLL setup. The driver parses the
device's BIOS to retrieve clock limits and reference clocks. With no BIOS
found, safe defaults are being used.

v2:
	* copy BIOS ROM to system memory and access with regular
	  load/store; resolves potential HW limitations
	* fix some stray whitespaces

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Co-developed-by: Egbert Eich <eich@suse.com>
Signed-off-by: Egbert Eich <eich@suse.com>
Co-developed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200730102844.10995-9-tzimmermann@suse.de

1 files changed, 80 insertions, 0 deletions

diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c
index 752409c7f326..38672f9e5c4f 100644
--- a/drivers/gpu/drm/mgag200/mgag200_mode.c
+++ b/drivers/gpu/drm/mgag200/mgag200_mode.c
@@ -108,6 +108,77 @@ static inline void mga_wait_busy(struct mga_device *mdev)
 	} while ((status & 0x01) && time_before(jiffies, timeout));
 }
 
+/*
+ * PLL setup
+ */
+
+static int mgag200_g200_set_plls(struct mga_device *mdev, long clock)
+{
+	struct drm_device *dev = &mdev->base;
+	const int post_div_max = 7;
+	const int in_div_min = 1;
+	const int in_div_max = 6;
+	const int feed_div_min = 7;
+	const int feed_div_max = 127;
+	u8 testm, testn;
+	u8 n = 0, m = 0, p, s;
+	long f_vco;
+	long computed;
+	long delta, tmp_delta;
+	long ref_clk = mdev->model.g200.ref_clk;
+	long p_clk_min = mdev->model.g200.pclk_min;
+	long p_clk_max =  mdev->model.g200.pclk_max;
+
+	if (clock > p_clk_max) {
+		drm_err(dev, "Pixel Clock %ld too high\n", clock);
+		return 1;
+	}
+
+	if (clock < p_clk_min >> 3)
+		clock = p_clk_min >> 3;
+
+	f_vco = clock;
+	for (p = 0;
+	     p <= post_div_max && f_vco < p_clk_min;
+	     p = (p << 1) + 1, f_vco <<= 1)
+		;
+
+	delta = clock;
+
+	for (testm = in_div_min; testm <= in_div_max; testm++) {
+		for (testn = feed_div_min; testn <= feed_div_max; testn++) {
+			computed = ref_clk * (testn + 1) / (testm + 1);
+			if (computed < f_vco)
+				tmp_delta = f_vco - computed;
+			else
+				tmp_delta = computed - f_vco;
+			if (tmp_delta < delta) {
+				delta = tmp_delta;
+				m = testm;
+				n = testn;
+			}
+		}
+	}
+	f_vco = ref_clk * (n + 1) / (m + 1);
+	if (f_vco < 100000)
+		s = 0;
+	else if (f_vco < 140000)
+		s = 1;
+	else if (f_vco < 180000)
+		s = 2;
+	else
+		s = 3;
+
+	drm_dbg_kms(dev, "clock: %ld vco: %ld m: %d n: %d p: %d s: %d\n",
+		    clock, f_vco, m, n, p, s);
+
+	WREG_DAC(MGA1064_PIX_PLLC_M, m);
+	WREG_DAC(MGA1064_PIX_PLLC_N, n);
+	WREG_DAC(MGA1064_PIX_PLLC_P, (p | (s << 3)));
+
+	return 0;
+}
+
 #define P_ARRAY_SIZE 9
 
 static int mga_g200se_set_plls(struct mga_device *mdev, long clock)
@@ -717,6 +788,9 @@ static int mgag200_crtc_set_plls(struct mga_device *mdev, long clock)
 	u8 misc;
 
 	switch(mdev->type) {
+	case G200_PCI:
+	case G200_AGP:
+		return mgag200_g200_set_plls(mdev, clock);
 	case G200_SE_A:
 	case G200_SE_B:
 		return mga_g200se_set_plls(mdev, clock);
@@ -894,6 +968,12 @@ static void mgag200_set_dac_regs(struct mga_device *mdev)
 	};
 
 	switch (mdev->type) {
+	case G200_PCI:
+	case G200_AGP:
+		dacvalue[MGA1064_SYS_PLL_M] = 0x04;
+		dacvalue[MGA1064_SYS_PLL_N] = 0x2D;
+		dacvalue[MGA1064_SYS_PLL_P] = 0x19;
+		break;
 	case G200_SE_A:
 	case G200_SE_B:
 		dacvalue[MGA1064_VREF_CTL] = 0x03;