[PATCH v2] drm/ast: Add option to initialize palette on driver load

[Timothy Pearson <tpearson@xxxxxxxxxxxxxxxxxxxxx>]

Non-x86 systems, such as OpenPOWER and ARM machines, do not execute the ASPEED-
provided option ROM on system start.  As a result, the VGA palette registers
remain uninitialized, leading to odd colors and generally hard to read output
on the VGA port.

Add a new module option, ast_resetpalette, to enable loading a linear greyscale
palette into the VGA RAMDAC.  This option is intended for use by the first Linux
kernel to load after initial power on, such as the skiroot kernel on OpenPOWER
systems.
---
 drivers/gpu/drm/ast/ast_drv.c  |  4 ++++
 drivers/gpu/drm/ast/ast_drv.h  | 14 ++++++++++++++
 drivers/gpu/drm/ast/ast_main.c |  8 ++++++++
 drivers/gpu/drm/ast/ast_mode.c | 14 --------------
 4 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/ast/ast_drv.c b/drivers/gpu/drm/ast/ast_drv.c
index 69dab82a3771..8124eaa92ed3 100644
--- a/drivers/gpu/drm/ast/ast_drv.c
+++ b/drivers/gpu/drm/ast/ast_drv.c
@@ -1,5 +1,6 @@
 /*
  * Copyright 2012 Red Hat Inc.
+ * Copyright 2018 Raptor Engineering, LLC.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the
@@ -34,9 +35,12 @@
 #include "ast_drv.h"
 
 int ast_modeset = -1;
+int ast_resetpalette = -1;
 
 MODULE_PARM_DESC(modeset, "Disable/Enable modesetting");
+MODULE_PARM_DESC(resetpalette, "Disable/Enable palette reset on load");
 module_param_named(modeset, ast_modeset, int, 0400);
+module_param_named(resetpalette, ast_resetpalette, int, 0400);
 
 #define PCI_VENDOR_ASPEED 0x1a03
 
diff --git a/drivers/gpu/drm/ast/ast_drv.h b/drivers/gpu/drm/ast/ast_drv.h
index e6c4cd3dc50e..5e834e466b65 100644
--- a/drivers/gpu/drm/ast/ast_drv.h
+++ b/drivers/gpu/drm/ast/ast_drv.h
@@ -383,6 +383,20 @@ static inline int ast_bo_reserve(struct ast_bo *bo, bool no_wait)
 	return 0;
 }
 
+static inline void ast_load_palette_index(struct ast_private *ast,
+				     u8 index, u8 red, u8 green,
+				     u8 blue)
+{
+	ast_io_write8(ast, AST_IO_DAC_INDEX_WRITE, index);
+	ast_io_read8(ast, AST_IO_SEQ_PORT);
+	ast_io_write8(ast, AST_IO_DAC_DATA, red);
+	ast_io_read8(ast, AST_IO_SEQ_PORT);
+	ast_io_write8(ast, AST_IO_DAC_DATA, green);
+	ast_io_read8(ast, AST_IO_SEQ_PORT);
+	ast_io_write8(ast, AST_IO_DAC_DATA, blue);
+	ast_io_read8(ast, AST_IO_SEQ_PORT);
+}
+
 static inline void ast_bo_unreserve(struct ast_bo *bo)
 {
 	ttm_bo_unreserve(&bo->bo);
diff --git a/drivers/gpu/drm/ast/ast_main.c b/drivers/gpu/drm/ast/ast_main.c
index dac355812adc..f13329b9a14d 100644
--- a/drivers/gpu/drm/ast/ast_main.c
+++ b/drivers/gpu/drm/ast/ast_main.c
@@ -1,5 +1,6 @@
 /*
  * Copyright 2012 Red Hat Inc.
+ * Copyright 2018 Raptor Engineering, LLC.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the
@@ -32,6 +33,8 @@
 #include <drm/drm_fb_helper.h>
 #include <drm/drm_crtc_helper.h>
 
+extern int ast_resetpalette;
+
 void ast_set_index_reg_mask(struct ast_private *ast,
 			    uint32_t base, uint8_t index,
 			    uint8_t mask, uint8_t val)
@@ -483,6 +486,7 @@ int ast_driver_load(struct drm_device *dev, unsigned long flags)
 	struct ast_private *ast;
 	bool need_post;
 	int ret = 0;
+	int index = 0;
 
 	ast = kzalloc(sizeof(struct ast_private), GFP_KERNEL);
 	if (!ast)
@@ -565,6 +569,10 @@ int ast_driver_load(struct drm_device *dev, unsigned long flags)
 	if (ret)
 		goto out_free;
 
+	if (ast_resetpalette == 1)
+		for (index = 0x00; index < 0x100; index++)
+			ast_load_palette_index(ast, index, index, index, index);
+
 	return 0;
 out_free:
 	kfree(ast);
diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index 9555a3542022..9afc4d53bd60 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -46,20 +46,6 @@ static int ast_cursor_set(struct drm_crtc *crtc,
 static int ast_cursor_move(struct drm_crtc *crtc,
 			   int x, int y);
 
-static inline void ast_load_palette_index(struct ast_private *ast,
-				     u8 index, u8 red, u8 green,
-				     u8 blue)
-{
-	ast_io_write8(ast, AST_IO_DAC_INDEX_WRITE, index);
-	ast_io_read8(ast, AST_IO_SEQ_PORT);
-	ast_io_write8(ast, AST_IO_DAC_DATA, red);
-	ast_io_read8(ast, AST_IO_SEQ_PORT);
-	ast_io_write8(ast, AST_IO_DAC_DATA, green);
-	ast_io_read8(ast, AST_IO_SEQ_PORT);
-	ast_io_write8(ast, AST_IO_DAC_DATA, blue);
-	ast_io_read8(ast, AST_IO_SEQ_PORT);
-}
-
 static void ast_crtc_load_lut(struct drm_crtc *crtc)
 {
 	struct ast_private *ast = crtc->dev->dev_private;
-- 
2.15.1

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