/*
* U-boot - start.S Startup file for Blackfin u-boot
*
- * Copyright (c) 2005-2007 Analog Devices Inc.
+ * Copyright (c) 2005-2008 Analog Devices Inc.
*
* This file is based on head.S
* Copyright (c) 2003 Metrowerks/Motorola
ENTRY(_start)
/* Set our initial stack to L1 scratch space */
- sp.l = LO(L1_SRAM_SCRATCH + L1_SRAM_SCRATCH_SIZE);
- sp.h = HI(L1_SRAM_SCRATCH + L1_SRAM_SCRATCH_SIZE);
+ sp.l = LO(L1_SRAM_SCRATCH_END - 20);
+ sp.h = HI(L1_SRAM_SCRATCH_END - 20);
#ifdef CONFIG_HW_WATCHDOG
# ifndef CONFIG_HW_WATCHDOG_TIMEOUT_START
serial_early_puts("Init Registers");
- /* Disable nested interrupts and enable CYCLES for udelay() */
+ /* Disable self-nested interrupts and enable CYCLES for udelay() */
R0 = CCEN | 0x30;
SYSCFG = R0;
*/
r6 = 1 (x);
- /* Relocate from wherever are (FLASH/RAM/etc...) to the
- * hardcoded monitor location in the end of RAM.
+ /* Relocate from wherever we are (FLASH/RAM/etc...) to the hardcoded
+ * monitor location in the end of RAM. We know that memcpy() only
+ * uses registers, so it is safe to call here. Note that this only
+ * copies to external memory ... we do not start executing out of
+ * it yet (see "lower to 15" below).
*/
serial_early_puts("Relocate");
call _get_pc;
r2.h = .Loffset;
r3.l = _start;
r3.h = _start;
- r1 = r2 - r3;
-
- r0 = r0 - r1;
-
- cc = r0 == r3;
+ r2 = r2 - r3;
+ r1 = r0 - r2;
+ cc = r1 == r3;
if cc jump .Lnorelocate;
-
r6 = 0 (x);
- p1 = r0;
- p2.l = LO(CFG_MONITOR_BASE);
- p2.h = HI(CFG_MONITOR_BASE);
-
- p3 = 0x04;
- p4.l = LO(CFG_MONITOR_BASE + CFG_MONITOR_LEN);
- p4.h = HI(CFG_MONITOR_BASE + CFG_MONITOR_LEN);
-.Lloop1:
- r1 = [p1 ++ p3];
- [p2 ++ p3] = r1;
- cc=p2==p4;
- if !cc jump .Lloop1;
+ r0 = r3;
+ r2.l = LO(CONFIG_SYS_MONITOR_LEN);
+ r2.h = HI(CONFIG_SYS_MONITOR_LEN);
+ call _memcpy_ASM;
/* Initialize BSS section ... we know that memset() does not
* use the BSS, so it is safe to call here. The bootrom LDR
.Lnorelocate:
/* Setup the actual stack in external memory */
- r0.h = HI(CONFIG_STACKBASE);
- r0.l = LO(CONFIG_STACKBASE);
- sp = r0;
+ sp.h = HI(CONFIG_STACKBASE);
+ sp.l = LO(CONFIG_STACKBASE);
fp = sp;
/* Now lower ourselves from the highest interrupt level to
* the lowest. We do this by masking all interrupts but 15,
- * setting the 15 handler to "board_init_f", raising the 15
+ * setting the 15 handler to ".Lenable_nested", raising the 15
* interrupt, and then returning from the highest interrupt
* level to the dummy "jump" until the interrupt controller
- * services the pending 15 interrupt.
+ * services the pending 15 interrupt. If executing out of
+ * flash, these steps also changes the code flow from flash
+ * to external memory.
*/
serial_early_puts("Lower to 15");
r0 = r7;
r1 = r6;
p0.l = LO(EVT15);
p0.h = HI(EVT15);
- p1.l = _cpu_init_f;
- p1.h = _cpu_init_f;
+ p1.l = .Lenable_nested;
+ p1.h = .Lenable_nested;
[p0] = p1;
- p2.l = LO(IMASK);
- p2.h = HI(IMASK);
- p3.l = LO(EVT_IVG15);
- p3.h = HI(EVT_IVG15);
- [p2] = p3;
+ r7 = EVT_IVG15 (z);
+ sti r7;
raise 15;
p4.l = .LWAIT_HERE;
p4.h = .LWAIT_HERE;
reti = p4;
rti;
+ /* Enable nested interrupts before continuing with cpu init */
+.Lenable_nested:
+ cli r7;
+ [--sp] = reti;
+ jump.l _cpu_init_f;
+
.LWAIT_HERE:
jump .LWAIT_HERE;
ENDPROC(_start)