drm/ast: Gen1: Fix open-coded register access

Replace all open-coded access to MCR registers in Gen1 with the
appropriate calls to ast_moutdwm() and ast_mindwm(). Use MCR register
constants.

For the poll loop on MCR100, add ast_moutdwm_poll(). The helper polls
the register until it has been updated to the given value. Relax the
CPU while busy-waiting.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patch.msgid.link/20260327133532.79696-11-tzimmermann@suse.de

4 files changed, 22 insertions, 11 deletions

diff --git a/drivers/gpu/drm/ast/ast_2000.c b/drivers/gpu/drm/ast/ast_2000.c
index e683edf595e2..4cf951b3533d 100644
--- a/drivers/gpu/drm/ast/ast_2000.c
+++ b/drivers/gpu/drm/ast/ast_2000.c
@@ -99,20 +99,15 @@ static const struct ast_dramstruct ast2000_dram_table_data[] = {
 static void ast_post_chip_2000(struct ast_device *ast)
 {
 	u8 j;
-	u32 temp, i;
-	const struct ast_dramstruct *dram_reg_info;
+	u32 i;
 
 	j = ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xd0, 0xff);
 
 	if ((j & 0x80) == 0) { /* VGA only */
-		dram_reg_info = ast2000_dram_table_data;
-		ast_write32(ast, 0xf004, AST_REG_MCR00);
-		ast_write32(ast, 0xf000, 0x1);
-		ast_write32(ast, 0x10100, 0xa8);
+		const struct ast_dramstruct *dram_reg_info = ast2000_dram_table_data;
+		u32 mcr140;
 
-		do {
-			;
-		} while (ast_read32(ast, 0x10100) != 0xa8);
+		ast_moutdwm_poll(ast, AST_REG_MCR100, 0xa8, 0xa8);
 
 		while (!AST_DRAMSTRUCT_IS(dram_reg_info, INVALID)) {
 			if (AST_DRAMSTRUCT_IS(dram_reg_info, UDELAY)) {
@@ -124,8 +119,9 @@ static void ast_post_chip_2000(struct ast_device *ast)
 			dram_reg_info++;
 		}
 
-		temp = ast_read32(ast, 0x10140);
-		ast_write32(ast, 0x10140, temp | 0x40);
+		mcr140 = ast_mindwm(ast, AST_REG_MCR140);
+		mcr140 |= 0x00000040;
+		ast_moutdwm(ast, AST_REG_MCR140, mcr140);
 	}
 
 	/* wait ready */
diff --git a/drivers/gpu/drm/ast/ast_drv.c b/drivers/gpu/drm/ast/ast_drv.c
index 3da0cce0a3f6..6fe549f16309 100644
--- a/drivers/gpu/drm/ast/ast_drv.c
+++ b/drivers/gpu/drm/ast/ast_drv.c
@@ -102,6 +102,18 @@ void ast_moutdwm(struct ast_device *ast, u32 r, u32 v)
 	__ast_moutdwm(ast->regs, r, v);
 }
 
+void ast_moutdwm_poll(struct ast_device *ast, u32 r, u32 v, u32 res)
+{
+	void __iomem *regs = ast->regs;
+
+	__ast_selseg(regs, r);
+	__ast_wrseg32(regs, r, v);
+
+	do {
+		cpu_relax();
+	} while (__ast_rdseg32(regs, r) != res);
+}
+
 /*
  * AST device
  */
diff --git a/drivers/gpu/drm/ast/ast_drv.h b/drivers/gpu/drm/ast/ast_drv.h
index 3eedf8239333..4f221b848d68 100644
--- a/drivers/gpu/drm/ast/ast_drv.h
+++ b/drivers/gpu/drm/ast/ast_drv.h
@@ -361,6 +361,7 @@ u32 __ast_mindwm(void __iomem *regs, u32 r);
 void __ast_moutdwm(void __iomem *regs, u32 r, u32 v);
 u32 ast_mindwm(struct ast_device *ast, u32 r);
 void ast_moutdwm(struct ast_device *ast, u32 r, u32 v);
+void ast_moutdwm_poll(struct ast_device *ast, u32 r, u32 v, u32 res);
 
 /*
  * VBIOS
diff --git a/drivers/gpu/drm/ast/ast_reg.h b/drivers/gpu/drm/ast/ast_reg.h
index a01af2bfbae6..9ebdbbde9a47 100644
--- a/drivers/gpu/drm/ast/ast_reg.h
+++ b/drivers/gpu/drm/ast/ast_reg.h
@@ -140,8 +140,10 @@
 #define AST_REG_MCR80				AST_REG_MCR(0x80)
 #define AST_REG_MCR84				AST_REG_MCR(0x84)
 #define AST_REG_MCR88				AST_REG_MCR(0x88)
+#define AST_REG_MCR100				AST_REG_MCR(0x100)
 #define AST_REG_MCR108				AST_REG_MCR(0x108)
 #define AST_REG_MCR120				AST_REG_MCR(0x120)
+#define AST_REG_MCR140				AST_REG_MCR(0x140)
 #define AST_REG_MCR200				AST_REG_MCR(0x200)
 #define AST_REG_MCR204				AST_REG_MCR(0x204)
 #define AST_REG_MCR208				AST_REG_MCR(0x208)