Seperate compilation of scratch rom

src/board/system76/galp3-c/board.mk

@@ -8,3 +8,37 @@ CFLAGS+=-DLEVEL=2
 
 # Enable I2C debug on 0x76
 # CFLAGS+=-DI2C_DEBUGGER=0x76
+
+# Add scratch ROM source
+SCRATCH_SRC=$(wildcard $(BOARD_DIR)/scratch/*.c)
+SCRATCH_OBJ=$(patsubst src/%.c,$(BUILD)/%.rel,$(SCRATCH_SRC))
+SCRATCH_CC=\
+	sdcc \
+	-mmcs51 \
+	--model-small \
+	--code-size 1024 \
+	--Werror
+
+# Convert from binary file to C header
+$(BUILD)/include/scratch.h: $(BUILD)/scratch.rom
+	@mkdir -p $(@D)
+	xxd --include < $< > $@
+
+# Convert from Intel Hex file to binary file
+$(BUILD)/scratch.rom: $(BUILD)/scratch.ihx
+	@mkdir -p $(@D)
+	makebin -p < $< > $@
+
+# Link object files into Intel Hex file
+$(BUILD)/scratch.ihx: $(SCRATCH_OBJ)
+	@mkdir -p $(@D)
+	$(SCRATCH_CC) -o $@ $^
+
+# Compile C files into object files
+$(SCRATCH_OBJ): $(BUILD)/%.rel: src/%.c
+	@mkdir -p $(@D)
+	$(SCRATCH_CC) -o $@ -c $<
+
+# Require scratch.rom to be compiled before main firmware
+CFLAGS+=-I$(BUILD)/include
+INCLUDE+=$(BUILD)/include/scratch.h

src/board/system76/galp3-c/scratch.c

@@ -1,21 +1,22 @@
 #include <stdbool.h>
 #include <stdint.h>
 
-volatile uint8_t __xdata __at(0x103B) ECINDAR0;
+#include <common/macro.h>
-volatile uint8_t __xdata __at(0x103C) ECINDAR1;
+
-volatile uint8_t __xdata __at(0x103D) ECINDAR2;
+// Include scratch ROM, must be less than 1024 bytes, controlled by makefile
-volatile uint8_t __xdata __at(0x103E) ECINDAR3;
+uint8_t __code scratch_rom[] = {
-volatile uint8_t __xdata __at(0x103F) ECINDDR;
+    #include <scratch.h>
-volatile uint8_t __xdata __at(0x1040) SCAR0L;
+};
-volatile uint8_t __xdata __at(0x1041) SCAR0M;
+
-volatile uint8_t __xdata __at(0x1042) SCAR0H;
+// Scratch RAM 1 is 1024 bytes, located at 2048 bytes
+volatile uint8_t __xdata __at(0x0800) scratch_ram_1[1024];
+
 volatile uint8_t __xdata __at(0x1043) SCAR1L;
 volatile uint8_t __xdata __at(0x1044) SCAR1M;
 volatile uint8_t __xdata __at(0x1045) SCAR1H;
 
-// Create new segment located at 0x1000
+// Create new segment located at 0x1000, after scratch ROM mapping
-static void scratch_start(void) __naked
+static void scratch_start(void) __naked {
-{
 	__asm
 		.area SCRATCH (ABS,CODE)
 	__endasm;
@@ -24,52 +25,37 @@ static void scratch_start(void) __naked
 	__endasm;
 }
 
-#define FLASH_SPI 0x00000000
+// Enter scratch ROM
-#define FLASH_EMBEDDED 0x40000000
+int scratch_trampoline(void) {
+	// Uses SCAR1 which is mapped at 0x0800 in data space and is 1024 bytes in
+	// size. SCAR0 cannot be used due to __pdata overwriting it.
 
-static int flash_transaction(uint32_t offset, uint8_t * data, int length, bool read) {
     int i;
-    for (i = 0; i < length; i++, offset++) {
+    // Copy scratch ROM
-        ECINDAR3 = (uint8_t)(offset >> 24);
+    for (i = 0; i < ARRAY_SIZE(scratch_rom) && i < ARRAY_SIZE(scratch_ram_1); i++) {
-        ECINDAR2 = (uint8_t)(offset >> 16);
+        scratch_ram_1[i] = scratch_rom[i];
-        ECINDAR1 = (uint8_t)(offset >> 8);
-        ECINDAR0 = (uint8_t)(offset);
-        if (read) {
-            data[i] = ECINDDR;
-        } else {
-            ECINDDR = data[i];
     }
-    }
-    return i;
-}
 
-// Main program while running in scratch ROM
+    // Fill the rest with nop
-static void scratch_main(void) {
+    for (; i < ARRAY_SIZE(scratch_ram_1); i++) {
-    // TODO: implement flashing protocol and prevent access to flash
+        scratch_ram_1[i] = 0x00;
-	// data (i.e. calling functions in CSEG) during this process
+    }
-	for (;;) {}
+
+    // Set mapping at 0x0000 and enable
+    SCAR1L = 0x00;
+    SCAR1M = 0x00;
+    SCAR1H = 0x00;
+
+    // Jump to scratch reset function
+    __asm__("ljmp 0");
+
+    // Should never happen
+    return 0;
 }
 
 // Finish segment located at 0x1000
-static void scratch_end(void) __naked
+static void scratch_end(void) __naked {
-{
 	__asm
 		.area CSEG (REL,CODE)
 	__endasm;
 }
-
-// Enter scratch ROM
-void scratch_trampoline(void) {
-	// Uses SCAR1 which is mapped at 0x0800 in data space and is 1024 bytes in
-	// size. SCAR0 cannot be used due to __pdata overwriting it.
-
-    // Set flag to use DMA on next write
-    SCAR1H = 0x80;
-    // Set mapping at 0x1000
-    SCAR1L = 0x00;
-    SCAR1M = 0x10;
-    // Set DMA and enable code space mapping
-    SCAR1H = 0x00;
-
-    scratch_main();
-}

src/board/system76/galp3-c/scratch/main.c

@@ -0,0 +1,34 @@
+#include <stdbool.h>
+#include <stdint.h>
+
+volatile uint8_t __xdata __at(0x103B) ECINDAR0;
+volatile uint8_t __xdata __at(0x103C) ECINDAR1;
+volatile uint8_t __xdata __at(0x103D) ECINDAR2;
+volatile uint8_t __xdata __at(0x103E) ECINDAR3;
+volatile uint8_t __xdata __at(0x103F) ECINDDR;
+
+#define FLASH_SPI 0x00000000
+#define FLASH_EMBEDDED 0x40000000
+
+static int flash_transaction(uint32_t offset, uint8_t * data, int length, bool read) {
+    int i;
+    for (i = 0; i < length; i++, offset++) {
+        ECINDAR3 = (uint8_t)(offset >> 24);
+        ECINDAR2 = (uint8_t)(offset >> 16);
+        ECINDAR1 = (uint8_t)(offset >> 8);
+        ECINDAR0 = (uint8_t)(offset);
+        if (read) {
+            data[i] = ECINDDR;
+        } else {
+            ECINDDR = data[i];
+        }
+    }
+    return i;
+}
+
+// Main program while running in scratch ROM
+void main(void) {
+    // TODO: implement flashing protocol and prevent access to flash
+	// data (i.e. calling functions in CSEG) during this process
+	for (;;) {}
+}