drm/ast: Fixed system hanged if disable P2A

[ Upstream commit 6c971c09f38704513c426ba6515f22fb3d6c87d5 ]

The original ast driver will access some BMC configuration through P2A bridge
that can be disabled since AST2300 and after.
It will cause system hanged if P2A bridge is disabled.
Here is the update to fix it.

Signed-off-by: Y.C. Chen <yc_chen@aspeedtech.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>

3 files changed, 97 insertions, 79 deletions

diff --git a/drivers/gpu/drm/ast/ast_drv.h b/drivers/gpu/drm/ast/ast_drv.h
index 86205a28e56b..d33ea7ff8614 100644
--- a/drivers/gpu/drm/ast/ast_drv.h
+++ b/drivers/gpu/drm/ast/ast_drv.h
@@ -113,6 +113,7 @@ struct ast_private {
 	struct ttm_bo_kmap_obj cache_kmap;
 	int next_cursor;
 	bool support_wide_screen;
+	bool DisableP2A;
 
 	enum ast_tx_chip tx_chip_type;
 	u8 dp501_maxclk;
diff --git a/drivers/gpu/drm/ast/ast_main.c b/drivers/gpu/drm/ast/ast_main.c
index e53dbc90fcb6..dacfe512a93f 100644
--- a/drivers/gpu/drm/ast/ast_main.c
+++ b/drivers/gpu/drm/ast/ast_main.c
@@ -124,6 +124,12 @@ static int ast_detect_chip(struct drm_device *dev, bool *need_post)
 	} else
 		*need_post = false;
 
+	/* Check P2A Access */
+	ast->DisableP2A = true;
+	data = ast_read32(ast, 0xf004);
+	if (data != 0xFFFFFFFF)
+		ast->DisableP2A = false;
+
 	/* Check if we support wide screen */
 	switch (ast->chip) {
 	case AST1180:
@@ -140,15 +146,17 @@ static int ast_detect_chip(struct drm_device *dev, bool *need_post)
 			ast->support_wide_screen = true;
 		else {
 			ast->support_wide_screen = false;
-			/* Read SCU7c (silicon revision register) */
-			ast_write32(ast, 0xf004, 0x1e6e0000);
-			ast_write32(ast, 0xf000, 0x1);
-			data = ast_read32(ast, 0x1207c);
-			data &= 0x300;
-			if (ast->chip == AST2300 && data == 0x0) /* ast1300 */
-				ast->support_wide_screen = true;
-			if (ast->chip == AST2400 && data == 0x100) /* ast1400 */
-				ast->support_wide_screen = true;
+			if (ast->DisableP2A == false) {
+				/* Read SCU7c (silicon revision register) */
+				ast_write32(ast, 0xf004, 0x1e6e0000);
+				ast_write32(ast, 0xf000, 0x1);
+				data = ast_read32(ast, 0x1207c);
+				data &= 0x300;
+				if (ast->chip == AST2300 && data == 0x0) /* ast1300 */
+					ast->support_wide_screen = true;
+				if (ast->chip == AST2400 && data == 0x100) /* ast1400 */
+					ast->support_wide_screen = true;
+			}
 		}
 		break;
 	}
@@ -216,80 +224,81 @@ static int ast_get_dram_info(struct drm_device *dev)
 	uint32_t data, data2;
 	uint32_t denum, num, div, ref_pll;
 
-	ast_write32(ast, 0xf004, 0x1e6e0000);
-	ast_write32(ast, 0xf000, 0x1);
-
-
-	ast_write32(ast, 0x10000, 0xfc600309);
-
-	do {
-		if (pci_channel_offline(dev->pdev))
-			return -EIO;
-	} while (ast_read32(ast, 0x10000) != 0x01);
-	data = ast_read32(ast, 0x10004);
-
-	if (data & 0x40)
+	if (ast->DisableP2A)
+	{
 		ast->dram_bus_width = 16;
+		ast->dram_type = AST_DRAM_1Gx16;
+		ast->mclk = 396;
+	}
 	else
-		ast->dram_bus_width = 32;
+	{
+		ast_write32(ast, 0xf004, 0x1e6e0000);
+		ast_write32(ast, 0xf000, 0x1);
+		data = ast_read32(ast, 0x10004);
+
+		if (data & 0x40)
+			ast->dram_bus_width = 16;
+		else
+			ast->dram_bus_width = 32;
+
+		if (ast->chip == AST2300 || ast->chip == AST2400) {
+			switch (data & 0x03) {
+			case 0:
+				ast->dram_type = AST_DRAM_512Mx16;
+				break;
+			default:
+			case 1:
+				ast->dram_type = AST_DRAM_1Gx16;
+				break;
+			case 2:
+				ast->dram_type = AST_DRAM_2Gx16;
+				break;
+			case 3:
+				ast->dram_type = AST_DRAM_4Gx16;
+				break;
+			}
+		} else {
+			switch (data & 0x0c) {
+			case 0:
+			case 4:
+				ast->dram_type = AST_DRAM_512Mx16;
+				break;
+			case 8:
+				if (data & 0x40)
+					ast->dram_type = AST_DRAM_1Gx16;
+				else
+					ast->dram_type = AST_DRAM_512Mx32;
+				break;
+			case 0xc:
+				ast->dram_type = AST_DRAM_1Gx32;
+				break;
+			}
+		}
 
-	if (ast->chip == AST2300 || ast->chip == AST2400) {
-		switch (data & 0x03) {
-		case 0:
-			ast->dram_type = AST_DRAM_512Mx16;
-			break;
-		default:
-		case 1:
-			ast->dram_type = AST_DRAM_1Gx16;
-			break;
-		case 2:
-			ast->dram_type = AST_DRAM_2Gx16;
-			break;
+		data = ast_read32(ast, 0x10120);
+		data2 = ast_read32(ast, 0x10170);
+		if (data2 & 0x2000)
+			ref_pll = 14318;
+		else
+			ref_pll = 12000;
+
+		denum = data & 0x1f;
+		num = (data & 0x3fe0) >> 5;
+		data = (data & 0xc000) >> 14;
+		switch (data) {
 		case 3:
-			ast->dram_type = AST_DRAM_4Gx16;
-			break;
-		}
-	} else {
-		switch (data & 0x0c) {
-		case 0:
-		case 4:
-			ast->dram_type = AST_DRAM_512Mx16;
+			div = 0x4;
 			break;
-		case 8:
-			if (data & 0x40)
-				ast->dram_type = AST_DRAM_1Gx16;
-			else
-				ast->dram_type = AST_DRAM_512Mx32;
+		case 2:
+		case 1:
+			div = 0x2;
 			break;
-		case 0xc:
-			ast->dram_type = AST_DRAM_1Gx32;
+		default:
+			div = 0x1;
 			break;
 		}
+		ast->mclk = ref_pll * (num + 2) / (denum + 2) * (div * 1000);
 	}
-
-	data = ast_read32(ast, 0x10120);
-	data2 = ast_read32(ast, 0x10170);
-	if (data2 & 0x2000)
-		ref_pll = 14318;
-	else
-		ref_pll = 12000;
-
-	denum = data & 0x1f;
-	num = (data & 0x3fe0) >> 5;
-	data = (data & 0xc000) >> 14;
-	switch (data) {
-	case 3:
-		div = 0x4;
-		break;
-	case 2:
-	case 1:
-		div = 0x2;
-		break;
-	default:
-		div = 0x1;
-		break;
-	}
-	ast->mclk = ref_pll * (num + 2) / (denum + 2) * (div * 1000);
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/ast/ast_post.c b/drivers/gpu/drm/ast/ast_post.c
index 30672a3df8a9..270e8fb2803f 100644
--- a/drivers/gpu/drm/ast/ast_post.c
+++ b/drivers/gpu/drm/ast/ast_post.c
@@ -375,12 +375,20 @@ void ast_post_gpu(struct drm_device *dev)
 	ast_enable_mmio(dev);
 	ast_set_def_ext_reg(dev);
 
-	if (ast->chip == AST2300 || ast->chip == AST2400)
-		ast_init_dram_2300(dev);
-	else
-		ast_init_dram_reg(dev);
+	if (ast->DisableP2A == false)
+	{
+		if (ast->chip == AST2300 || ast->chip == AST2400)
+			ast_init_dram_2300(dev);
+		else
+			ast_init_dram_reg(dev);
 
-	ast_init_3rdtx(dev);
+		ast_init_3rdtx(dev);
+	}
+	else
+	{
+		if (ast->tx_chip_type != AST_TX_NONE)
+			ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xa3, 0xcf, 0x80);	/* Enable DVO */
+	}
 }
 
 /* AST 2300 DRAM settings */