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+/*
+ * U-boot - start.S Startup file for Blackfin u-boot
+ *
+ * Copyright (c) 2005-2007 Analog Devices Inc.
+ *
+ * This file is based on head.S
+ * Copyright (c) 2003 Metrowerks/Motorola
+ * Copyright (C) 1998 D. Jeff Dionne <jeff@ryeham.ee.ryerson.ca>,
+ * Kenneth Albanowski <kjahds@kjahds.com>,
+ * The Silver Hammer Group, Ltd.
+ * (c) 1995, Dionne & Associates
+ * (c) 1995, DKG Display Tech.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+ * MA 02110-1301 USA
+ */
+
+#include <config.h>
+#include <asm/blackfin.h>
+#include <asm/mach-common/bits/core.h>
+#include <asm/mach-common/bits/dma.h>
+#include <asm/mach-common/bits/pll.h>
+
+#include "serial.h"
+
+/* It may seem odd that we make calls to functions even though we haven't
+ * relocated ourselves yet out of {flash,ram,wherever}. This is OK because
+ * the "call" instruction in the Blackfin architecture is actually PC
+ * relative. So we can call functions all we want and not worry about them
+ * not being relocated yet.
+ */
+
+.text
+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);
+
+#ifdef CONFIG_HW_WATCHDOG
+# ifndef CONFIG_HW_WATCHDOG_TIMEOUT_START
+# define CONFIG_HW_WATCHDOG_TIMEOUT_START 5000
+# endif
+ /* Program the watchdog with an initial timeout of ~5 seconds.
+ * That should be long enough to bootstrap ourselves up and
+ * then the common u-boot code can take over.
+ */
+ P0.L = LO(WDOG_CNT);
+ P0.H = HI(WDOG_CNT);
+ R0.L = 0;
+ R0.H = HI(MSEC_TO_SCLK(CONFIG_HW_WATCHDOG_TIMEOUT_START));
+ [P0] = R0;
+ /* fire up the watchdog - R0.L above needs to be 0x0000 */
+ W[P0 + (WDOG_CTL - WDOG_CNT)] = R0;
+#endif
+
+ /* Turn on the serial for debugging the init process */
+ serial_early_init
+ serial_early_set_baud
+
+ serial_early_puts("Init Registers");
+
+ /* Disable nested interrupts and enable CYCLES for udelay() */
+ R0 = CCEN | 0x30;
+ SYSCFG = R0;
+
+ /* Zero out registers required by Blackfin ABI.
+ * http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
+ */
+ r1 = 0 (x);
+ /* Disable circular buffers */
+ l0 = r1;
+ l1 = r1;
+ l2 = r1;
+ l3 = r1;
+ /* Disable hardware loops in case we were started by 'go' */
+ lc0 = r1;
+ lc1 = r1;
+
+ /* Save RETX so we can pass it while booting Linux */
+ r7 = RETX;
+
+#if (CONFIG_BFIN_BOOT_MODE == BFIN_BOOT_BYPASS)
+ /* In bypass mode, we don't have an LDR with an init block
+ * so we need to explicitly call it ourselves. This will
+ * reprogram our clocks and setup our async banks.
+ */
+ /* XXX: we should DMA this into L1, put external memory into
+ * self refresh, and then jump there ...
+ */
+ call _get_pc;
+ r3 = 0x0;
+ r3.h = 0x2000;
+ cc = r0 < r3 (iu);
+ if cc jump .Lproc_initialized;
+
+ serial_early_puts("Program Clocks");
+
+ call _initcode;
+
+ /* Since we reprogrammed SCLK, we need to update the serial divisor */
+ serial_early_set_baud
+
+.Lproc_initialized:
+#endif
+
+ /* Inform upper layers if we had to do the relocation ourselves.
+ * This allows us to detect whether we were loaded by 'go 0x1000'
+ * or by the bootrom from an LDR. "r6" is "loaded_from_ldr".
+ */
+ r6 = 1 (x);
+
+ /* Relocate from wherever are (FLASH/RAM/etc...) to the
+ * hardcoded monitor location in the end of RAM.
+ */
+ serial_early_puts("Relocate");
+ call _get_pc;
+.Loffset:
+ r2.l = .Loffset;
+ r2.h = .Loffset;
+ r3.l = _start;
+ r3.h = _start;
+ r1 = r2 - r3;
+
+ r0 = r0 - r1;
+
+ cc = r0 == 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;
+
+ /* Initialize BSS section ... we know that memset() does not
+ * use the BSS, so it is safe to call here. The bootrom LDR
+ * takes care of clearing things for us.
+ */
+ serial_early_puts("Zero BSS");
+ r0.l = __bss_start;
+ r0.h = __bss_start;
+ r1 = 0 (x);
+ r2.l = __bss_end;
+ r2.h = __bss_end;
+ r2 = r2 - r0;
+ call _memset;
+
+.Lnorelocate:
+
+ /* Setup the actual stack in external memory */
+ r0.h = HI(CONFIG_STACKBASE);
+ r0.l = LO(CONFIG_STACKBASE);
+ sp = r0;
+ 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
+ * interrupt, and then returning from the highest interrupt
+ * level to the dummy "jump" until the interrupt controller
+ * services the pending 15 interrupt.
+ */
+ 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;
+ [p0] = p1;
+ p2.l = LO(IMASK);
+ p2.h = HI(IMASK);
+ p3.l = LO(EVT_IVG15);
+ p3.h = HI(EVT_IVG15);
+ [p2] = p3;
+ raise 15;
+ p4.l = .LWAIT_HERE;
+ p4.h = .LWAIT_HERE;
+ reti = p4;
+ rti;
+
+.LWAIT_HERE:
+ jump .LWAIT_HERE;
+ENDPROC(_start)
+
+LENTRY(_get_pc)
+ r0 = rets;
+#if ANOMALY_05000371
+ NOP;
+ NOP;
+ NOP;
+#endif
+ rts;
+ENDPROC(_get_pc)