From 8094fb30f6c072ab9f3ffda1079315c5a9c52b2d Mon Sep 17 00:00:00 2001
From: Maxim Poliakovski <maximumspatium@googlemail.com>
Date: Thu, 11 Jun 2020 01:30:10 +0200
Subject: [PATCH] atirage: add access to internal DAC palette.

---
 devices/atirage.cpp | 36 +++++++++++++++++++++++++++++++++++-
 devices/atirage.h   |  7 +++++++
 2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/devices/atirage.cpp b/devices/atirage.cpp
index 1747d1e..e85f0e6 100644
--- a/devices/atirage.cpp
+++ b/devices/atirage.cpp
@@ -170,7 +170,17 @@ uint32_t ATIRage::read_reg(uint32_t offset, uint32_t size) {
     uint32_t res;
 
     switch (offset & ~3) {
-    case ATI_GP_IO:
+    case ATI_DAC_REGS:
+        if (offset == ATI_DAC_DATA) {
+            this->block_io_regs[ATI_DAC_DATA] =
+                this->palette[this->block_io_regs[ATI_DAC_R_INDEX]][this->comp_index];
+            this->comp_index++; /* move to next color component */
+            if (this->comp_index >= 3) {
+                /* autoincrement reading index - move to next palette entry */
+                (this->block_io_regs[ATI_DAC_R_INDEX])++;
+                this->comp_index = 0;
+            }
+        }
         break;
     default:
         LOG_F(
@@ -204,6 +214,30 @@ void ATIRage::write_reg(uint32_t offset, uint32_t value, uint32_t size) {
                 this->disp_id->read_monitor_sense(gpio_val, gpio_dir));
         }
         break;
+    case ATI_DAC_REGS:
+        switch (offset) {
+        /* writing to read/write index registers resets color component index */
+        case ATI_DAC_W_INDEX:
+        case ATI_DAC_R_INDEX:
+            this->comp_index = 0;
+            break;
+        case ATI_DAC_DATA:
+            this->palette[this->block_io_regs[ATI_DAC_W_INDEX]][this->comp_index] = value & 0xFF;
+            this->comp_index++; /* move to next color component */
+            if (this->comp_index >= 3) {
+                LOG_F(
+                    INFO,
+                    "ATI DAC palette entry #%d set to R=%X, G=%X, B=%X",
+                    this->block_io_regs[ATI_DAC_W_INDEX],
+                    this->palette[this->block_io_regs[ATI_DAC_W_INDEX]][0],
+                    this->palette[this->block_io_regs[ATI_DAC_W_INDEX]][1],
+                    this->palette[this->block_io_regs[ATI_DAC_W_INDEX]][2]);
+                /* autoincrement writing index - move to next palette entry */
+                (this->block_io_regs[ATI_DAC_W_INDEX])++;
+                this->comp_index = 0;
+            }
+        }
+        break;
     default:
         LOG_F(
             INFO,
diff --git a/devices/atirage.h b/devices/atirage.h
index f57b7fe..60b6d70 100644
--- a/devices/atirage.h
+++ b/devices/atirage.h
@@ -80,6 +80,10 @@ enum {
     ATI_VGA_RP_SEL           = 0x00B8,
     ATI_I2C_CNTL_1           = 0x00BC,
     ATI_DAC_REGS             = 0x00C0,
+    ATI_DAC_W_INDEX          = 0x00C0,
+    ATI_DAC_DATA             = 0x00C1,
+    ATI_DAC_MASK             = 0x00C2,
+    ATI_DAC_R_INDEX          = 0x00C3,
     ATI_DAC_CNTL             = 0x00C4,
     ATI_GEN_TEST_CNTL        = 0x00D0,
     ATI_CUSTOM_MACRO_CNTL    = 0x00D4,
@@ -155,5 +159,8 @@ private:
     uint32_t    aperture_base;
 
     DisplayID*  disp_id;
+
+    uint8_t palette[256][4]; /* internal DAC palette in RGBA format */
+    int comp_index;          /* color component index for DAC palette access */
 };
 #endif /* ATI_RAGE_H */