Set the ROM offset at the beginning of the image

Put the ROM offset into a field in the image header, at the bottom of
the NULL pointer reserved region. testimg.S adjusts this field so that
the handling of the ROM offset becomes "automatic".

fw/Makefile

@@ -40,7 +40,7 @@ ROMS    := $(wildcard roms/*.rom)
 ROMOBJS  = $(ROMS:.rom=.o)
 
 max80.elf: head.o die.o main.o dummy.o irqtable.o irqasm.o sbrk.o \
-	  console.o rtc.o \
+	  console.o rtc.o romcopy.o \
 	  sdcard.o diskcache.o \
 	  abcio.o abcdisk.o \
 	  memset.o memcpy.o \
@@ -49,7 +49,7 @@ max80.elf: head.o die.o main.o dummy.o irqtable.o irqasm.o sbrk.o \
 	  fatfs.a
 
 testimg.elf: head.o die.o test/main.o dummy.o irqtable.o irqasm.o sbrk.o \
-	  console.o rtc.o \
+	  console.o rtc.o romcopy.o \
 	  sdcard.o diskcache.o \
 	  abcio.o abcdisk.o \
 	  memset.o memcpy.o \

fw/fw.h

@@ -56,6 +56,8 @@ typedef union xcptr {
 #define __dram_bss	__attribute__((section(".dram.bss")))
 #define __dram_noinit	__attribute__((section(".dram.noinit")))
 
+extern const size_t __rom_offset;
+
 extern no_return _die(void);
 extern no_return exit(int);
 extern no_return _exit(int);
@@ -68,4 +70,6 @@ extern void mount_abcdrives(void);
 
 extern void read_rtc(void);
 
+extern uint32_t romcopy_time[2];
+
 #endif /* FW_H */

fw/head.S

@@ -10,11 +10,22 @@
 	// NULL pointer guard area
 	// This needs to be an explicitly allocated section or the binary
 	// memory initialization file ends up broken.
+	//
+	// This also contains a pointer to the ROM area associated
+	// with this image. For a non-primary image it is patched to
+	// the preferred value.
 	.section ".null","a"
 	.globl _NULL
-_NULL:	.space _PC_RESET
+_NULL:
+	.space 12
 	.type	_NULL, @object
-	.size	_NULL, _PC_RESET
+	.size	_NULL, . - _NULL
+
+	.globl __rom_offset
+__rom_offset:
+	.long ROM_OFFSET
+	.type	__rom_offset, @object
+	.size	__rom_offset, . - __rom_offset
 
 	// The linker will always assign this to _PC_RESET
 	.section ".init.reset","ax"

fw/main.c

@@ -30,35 +30,6 @@ static void init_abc_memmap(void)
     }
 }
 
-extern const char __dram_init_start[], __dram_init_end[], __dram_init_len[];
-extern const char __dram_bss_start[], __dram_bss_end[], __dram_bss_len[];
-
-static uint32_t romcopy_time[2];
-static unsigned int romcopy_state;
-IRQHANDLER(romcopy)
-{
-    switch (romcopy_state++) {
-    case 0:
-	/* Copy testdata */
-	ROMCOPY_RAMADDR = (size_t)__dram_init_start;
-	ROMCOPY_ROMADDR = ROM_OFFSET;
-	ROMCOPY_DATALEN = (size_t)__dram_init_len;
-	break;
-    case 1:
-	/* Zero .dram.bss */
-	romcopy_time[0] = rdtime() - time_zero;
-
-	ROMCOPY_RAMADDR = (size_t)__dram_bss_start;
-	ROMCOPY_ROMADDR = 0;	/* Clear */
-	ROMCOPY_DATALEN = (size_t)__dram_bss_len;
-	break;
-    default:
-	romcopy_time[1] = rdtime() - romcopy_time[0];
-	mask_irq(ROMCOPY_IRQ);
-	return;
-    }
-}
-
 static no_return killed(const char *how, size_t pc)
 {
     con_printf("ERROR: %s at 0x%08x\n", how, pc);
@@ -86,7 +57,6 @@ static void init(void)
 	"Firmware compiled on: " __DATE__ " " __TIME__ "\n\n";
 
     /* Start ROM copy engine */
-    romcopy_state = 0;
     unmask_irqs((1U << ROMCOPY_IRQ)|(1U << EBREAK_IRQ)|(1U << BUSERR_IRQ));
 
     set_led(0);

fw/max80.ld

@@ -181,6 +181,9 @@ SECTIONS
 		__abcrom_end = .;
 		/* Make sure this section is not empty */
 		LONG(0xffffffff)
+		LONG(0xffffffff)
+		LONG(0xffffffff)
+		LONG(0xffffffff)
 	} >DRAM
 
 	.dram.text : ALIGN(4) {
@@ -201,7 +204,7 @@ SECTIONS
 
 	/* Test program image */
 	.dram.test : ALIGN(4) {
-		*(.dram.test*)
+		KEEP(*(.dram.test*))
 	} >DRAM
 
 	__dram_bss_start = .;

fw/romcopy.c

@@ -0,0 +1,32 @@
+#include "fw.h"
+#include "io.h"
+
+extern const char __dram_init_start[], __dram_init_end[], __dram_init_len[];
+extern const char __dram_bss_start[], __dram_bss_end[], __dram_bss_len[];
+
+uint32_t romcopy_time[2];
+IRQHANDLER(romcopy)
+{
+    static unsigned int romcopy_state;
+
+    switch (romcopy_state++) {
+    case 0:
+	/* Copy testdata */
+	ROMCOPY_RAMADDR = (size_t)__dram_init_start;
+	ROMCOPY_ROMADDR = __rom_offset;
+	ROMCOPY_DATALEN = (size_t)__dram_init_len;
+	break;
+    case 1:
+	/* Zero .dram.bss */
+	romcopy_time[0] = rdtime() - time_zero;
+
+	ROMCOPY_RAMADDR = (size_t)__dram_bss_start;
+	ROMCOPY_ROMADDR = 0;	/* Clear */
+	ROMCOPY_DATALEN = (size_t)__dram_bss_len;
+	break;
+    default:
+	romcopy_time[1] = rdtime() - romcopy_time[0];
+	mask_irq(ROMCOPY_IRQ);
+	return;
+    }
+}

fw/test/main.c

@@ -207,49 +207,6 @@ static void init(void)
     read_rtc();
 }
 
-static uint32_t romcopy_time[2];
-static unsigned int romcopy_state;
-extern const char __dram_init_start[], __dram_init_end[], __dram_init_len[];
-
-static uint32_t romcopy_time[2];
-static unsigned int romcopy_state;
-IRQHANDLER(romcopy)
-{
-    size_t rombase;
-
-    /*
-     * The handover code from the normal startup will set tp to
-     * our ROM area, not including the SRAM image.
-     */
-    asm("mv %0,tp" : "=r" (rombase));
-
-    if (rombase) {
-	/* Test-only ROM image? */
-	rombase = ROM_OFFSET;
-    }
-
-    switch (romcopy_state++) {
-    case 0:
-	/* Copy testdata */
-	ROMCOPY_RAMADDR = (size_t)__dram_init_start;
-	ROMCOPY_ROMADDR = rombase;
-	ROMCOPY_DATALEN = (size_t)__dram_init_len;
-	break;
-    case 1:
-	/* Zero .dram.bss */
-	romcopy_time[0] = rdtime() - time_zero;
-
-	ROMCOPY_RAMADDR = (size_t)__dram_bss_start;
-	ROMCOPY_ROMADDR = 0;	/* Clear */
-	ROMCOPY_DATALEN = (size_t)__dram_bss_len;
-	break;
-    default:
-	romcopy_time[1] = rdtime() - romcopy_time[0];
-	mask_irq(ROMCOPY_IRQ);
-	return;
-    }
-}
-
 static no_return killed(const char *how, size_t pc)
 {
     con_printf("ERROR: %s at 0x%08x\n", how, pc);
@@ -301,7 +258,6 @@ void main(void)
     unmask_irq(EBREAK_IRQ);
 
     CON_DATA = '3';
-    romcopy_state = 0;
     unmask_irq(ROMCOPY_IRQ);
 
     CON_DATA = '4';

fw/testimg.S

@@ -1,8 +1,15 @@
+#include "sys.h"
+
 	.section ".dram.test","a"
 
+	.balign 16
 	.globl __dram_test_start
 __dram_test_start:
-	.incbin "testimg.bin"
+	/* Override the rom offset pointer */
+	.long 0, 0, 0
+	.long __dram_test_start - SDRAM_ADDR + ROM_OFFSET + SRAM_SIZE
+
+	.incbin "testimg.bin", 16
 	.type __dram_test_start, @object
 	.size __dram_test_start, . - __dram_test_start