drm/nouveau: Implement nv42-nv43 TV load detection.

Signed-off-by: Francisco Jerez <currojerez@riseup.net>
diff --git a/drivers/gpu/drm/nouveau/nv17_tv.c b/drivers/gpu/drm/nouveau/nv17_tv.c
index 5fa4242..58b917c 100644
--- a/drivers/gpu/drm/nouveau/nv17_tv.c
+++ b/drivers/gpu/drm/nouveau/nv17_tv.c
@@ -33,15 +33,103 @@
 #include "nouveau_hw.h"
 #include "nv17_tv.h"
 
+static uint32_t nv42_tv_sample_load(struct drm_encoder *encoder)
+{
+	struct drm_device *dev = encoder->dev;
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	uint32_t testval, regoffset = nv04_dac_output_offset(encoder);
+	uint32_t gpio0, gpio1, fp_htotal, fp_hsync_start, fp_hsync_end,
+		fp_control, test_ctrl, dacclk, ctv_14, ctv_1c, ctv_6c;
+	uint32_t sample = 0;
+	int head;
+
+#define RGB_TEST_DATA(r, g, b) (r << 0 | g << 10 | b << 20)
+	testval = RGB_TEST_DATA(0x82, 0xeb, 0x82);
+	if (dev_priv->vbios->tvdactestval)
+		testval = dev_priv->vbios->tvdactestval;
+
+	dacclk = NVReadRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset);
+	head = (dacclk & 0x100) >> 8;
+
+	/* Save the previous state. */
+	gpio1 = nv17_gpio_get(dev, DCB_GPIO_TVDAC1);
+	gpio0 = nv17_gpio_get(dev, DCB_GPIO_TVDAC0);
+	fp_htotal = NVReadRAMDAC(dev, head, NV_PRAMDAC_FP_HTOTAL);
+	fp_hsync_start = NVReadRAMDAC(dev, head, NV_PRAMDAC_FP_HSYNC_START);
+	fp_hsync_end = NVReadRAMDAC(dev, head, NV_PRAMDAC_FP_HSYNC_END);
+	fp_control = NVReadRAMDAC(dev, head, NV_PRAMDAC_FP_TG_CONTROL);
+	test_ctrl = NVReadRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset);
+	ctv_1c = NVReadRAMDAC(dev, head, 0x680c1c);
+	ctv_14 = NVReadRAMDAC(dev, head, 0x680c14);
+	ctv_6c = NVReadRAMDAC(dev, head, 0x680c6c);
+
+	/* Prepare the DAC for load detection.  */
+	nv17_gpio_set(dev, DCB_GPIO_TVDAC1, true);
+	nv17_gpio_set(dev, DCB_GPIO_TVDAC0, true);
+
+	NVWriteRAMDAC(dev, head, NV_PRAMDAC_FP_HTOTAL, 1343);
+	NVWriteRAMDAC(dev, head, NV_PRAMDAC_FP_HSYNC_START, 1047);
+	NVWriteRAMDAC(dev, head, NV_PRAMDAC_FP_HSYNC_END, 1183);
+	NVWriteRAMDAC(dev, head, NV_PRAMDAC_FP_TG_CONTROL,
+		      NV_PRAMDAC_FP_TG_CONTROL_DISPEN_POS |
+		      NV_PRAMDAC_FP_TG_CONTROL_WIDTH_12 |
+		      NV_PRAMDAC_FP_TG_CONTROL_READ_PROG |
+		      NV_PRAMDAC_FP_TG_CONTROL_HSYNC_POS |
+		      NV_PRAMDAC_FP_TG_CONTROL_VSYNC_POS);
+
+	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset, 0);
+
+	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset,
+		      (dacclk & ~0xff) | 0x22);
+	msleep(1);
+	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset,
+		      (dacclk & ~0xff) | 0x21);
+
+	NVWriteRAMDAC(dev, head, 0x680c1c, 1 << 20);
+	NVWriteRAMDAC(dev, head, 0x680c14, 4 << 16);
+
+	/* Sample pin 0x4 (usually S-video luma). */
+	NVWriteRAMDAC(dev, head, 0x680c6c, testval >> 10 & 0x3ff);
+	msleep(20);
+	sample |= NVReadRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset)
+		& 0x4 << 28;
+
+	/* Sample the remaining pins. */
+	NVWriteRAMDAC(dev, head, 0x680c6c, testval & 0x3ff);
+	msleep(20);
+	sample |= NVReadRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset)
+		& 0xa << 28;
+
+	/* Restore the previous state. */
+	NVWriteRAMDAC(dev, head, 0x680c1c, ctv_1c);
+	NVWriteRAMDAC(dev, head, 0x680c14, ctv_14);
+	NVWriteRAMDAC(dev, head, 0x680c6c, ctv_6c);
+	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset, dacclk);
+	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset, test_ctrl);
+	NVWriteRAMDAC(dev, head, NV_PRAMDAC_FP_TG_CONTROL, fp_control);
+	NVWriteRAMDAC(dev, head, NV_PRAMDAC_FP_HSYNC_END, fp_hsync_end);
+	NVWriteRAMDAC(dev, head, NV_PRAMDAC_FP_HSYNC_START, fp_hsync_start);
+	NVWriteRAMDAC(dev, head, NV_PRAMDAC_FP_HTOTAL, fp_htotal);
+	nv17_gpio_set(dev, DCB_GPIO_TVDAC1, gpio1);
+	nv17_gpio_set(dev, DCB_GPIO_TVDAC0, gpio0);
+
+	return sample;
+}
+
 static enum drm_connector_status
 nv17_tv_detect(struct drm_encoder *encoder, struct drm_connector *connector)
 {
 	struct drm_device *dev = encoder->dev;
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
 	struct drm_mode_config *conf = &dev->mode_config;
 	struct nv17_tv_encoder *tv_enc = to_tv_enc(encoder);
 	struct dcb_entry *dcb = tv_enc->base.dcb;
 
-	tv_enc->pin_mask = nv17_dac_sample_load(encoder) >> 28 & 0xe;
+	if (dev_priv->chipset == 0x42 ||
+	    dev_priv->chipset == 0x43)
+		tv_enc->pin_mask = nv42_tv_sample_load(encoder) >> 28 & 0xe;
+	else
+		tv_enc->pin_mask = nv17_dac_sample_load(encoder) >> 28 & 0xe;
 
 	switch (tv_enc->pin_mask) {
 	case 0x2: