[PATCH 4.4 34/46] drm/ast: Fixed system hanged if disable P2A

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: "Y.C. Chen" <yc_chen@aspeedtech.com>


[ 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/ast/ast_drv.h  |    1 
 drivers/gpu/drm/ast/ast_main.c |  157 +++++++++++++++++++++--------------------
 drivers/gpu/drm/ast/ast_post.c |   18 +++-
 3 files changed, 97 insertions(+), 79 deletions(-)

--- 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;
--- 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_de
 	} 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_de
 			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_
 	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;
 }
 
--- 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 */