From ac12a91f5607d8839b9bcd82c60a9e15b932b778 Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jeremy@system76.com>
Date: Wed, 15 Jan 2020 16:26:10 -0700
Subject: [PATCH] Increase scratch ROM size for galp3-c

---
 src/board/system76/galp3-c/scratch.c          | 37 ++++++++++++-------
 src/board/system76/galp3-c/scratch/scratch.mk |  2 +-
 2 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/src/board/system76/galp3-c/scratch.c b/src/board/system76/galp3-c/scratch.c
index ef1b074..0e59ba3 100644
--- a/src/board/system76/galp3-c/scratch.c
+++ b/src/board/system76/galp3-c/scratch.c
@@ -3,13 +3,17 @@
 
 #include <common/macro.h>
 
-// Include scratch ROM, must be less than 2048 bytes, controlled by makefile
+// Include scratch ROM, must be less than 4096 bytes, controlled by makefile
 uint8_t __code scratch_rom[] = {
     #include <scratch.h>
 };
 
-// Scratch RAM 1, 2, 3, and 4 are 2048 bytes total, located at 0x0800 bytes
-volatile uint8_t __xdata __at(0x0800) scratch_ram[2048];
+// Scratch RAM 0, 1, 2, 3, and 4 are 4096 bytes total, located at 0x0000 bytes
+volatile uint8_t __xdata __at(0x0000) scratch_ram[4096];
+
+volatile uint8_t __xdata __at(0x1040) SCAR0L;
+volatile uint8_t __xdata __at(0x1041) SCAR0M;
+volatile uint8_t __xdata __at(0x1042) SCAR0H;
 
 volatile uint8_t __xdata __at(0x1043) SCAR1L;
 volatile uint8_t __xdata __at(0x1044) SCAR1M;
@@ -39,11 +43,12 @@ static void scratch_start(void) __naked {
 
 // Enter or exit scratch ROM
 void scratch_trampoline(void) {
-	// Uses SCAR1, 2, 3, and 4 which are mapped at 0x0800 in data space and are
-    // 2048 bytes in size. SCAR0 cannot be used due to __pdata overwriting it.
+	// Uses SCAR0, 1, 2, 3, and 4 which are mapped at 0x0000 in data space and are
+    // 4096 bytes in size.
 
-    if ((SCAR1H == 0x00) || (SCAR2H == 0x00) || (SCAR3H == 0x00) || (SCAR4H == 0x00)) {
+    if ((SCAR0H == 0x00) || (SCAR1H == 0x00) || (SCAR2H == 0x00) || (SCAR3H == 0x00) || (SCAR4H == 0x00)) {
         // Disable scratch RAM mapping
+        SCAR0H = 0b11;
         SCAR1H = 0b11;
         SCAR2H = 0b11;
         SCAR3H = 0b11;
@@ -60,21 +65,25 @@ void scratch_trampoline(void) {
             scratch_ram[i] = 0x00;
         }
 
-        // Set scratch RAM 1 mapping at 0x0000 and enable
+        // Set scratch RAM 0 mapping at 0x0000 and enable
+        SCAR0L = 0x00;
+        SCAR0M = 0x00;
+        SCAR0H = 0x00;
+        // Set scratch RAM 1 mapping at 0x0800 and enable
         SCAR1L = 0x00;
-        SCAR1M = 0x00;
+        SCAR1M = 0x08;
         SCAR1H = 0x00;
-        // Set scratch RAM 2 mapping at 0x0400 and enable
+        // Set scratch RAM 2 mapping at 0x0C00 and enable
         SCAR2L = 0x00;
-        SCAR2M = 0x04;
+        SCAR2M = 0x0C;
         SCAR2H = 0x00;
-        // Set scratch RAM 3 mapping at 0x0600 and enable
+        // Set scratch RAM 3 mapping at 0x0E00 and enable
         SCAR3L = 0x00;
-        SCAR3M = 0x06;
+        SCAR3M = 0x0E;
         SCAR3H = 0x00;
-        // Set scratch RAM 4 mapping at 0x0700 and enable
+        // Set scratch RAM 4 mapping at 0x0F00 and enable
         SCAR4L = 0x00;
-        SCAR4M = 0x07;
+        SCAR4M = 0x0F;
         SCAR4H = 0x00;
     }
 
diff --git a/src/board/system76/galp3-c/scratch/scratch.mk b/src/board/system76/galp3-c/scratch/scratch.mk
index ba018b5..981eb02 100644
--- a/src/board/system76/galp3-c/scratch/scratch.mk
+++ b/src/board/system76/galp3-c/scratch/scratch.mk
@@ -16,7 +16,7 @@ SCRATCH_CC=\
 	sdcc \
 	-mmcs51 \
 	--model-small \
-	--code-size 2048 \
+	--code-size 4096 \
 	--Werror
 
 # Convert from binary file to C header