| /* |
| * Initial board bringup code for many different boards. |
| * |
| * Author: Tom Rini |
| * trini@mvista.com |
| * Derived from arch/ppc/boot/prep/head.S (Cort Dougan, many others). |
| * |
| * 2001-2004 (c) MontaVista, Software, Inc. This file is licensed under |
| * the terms of the GNU General Public License version 2. This program |
| * is licensed "as is" without any warranty of any kind, whether express |
| * or implied. |
| */ |
| |
| #include <linux/config.h> |
| #include <asm/reg.h> |
| #include <asm/cache.h> |
| #include <asm/ppc_asm.h> |
| |
| .text |
| |
| /* |
| * Begin at some arbitrary location in RAM or Flash |
| * Initialize core registers |
| * Configure memory controller (Not executing from RAM) |
| * Move the boot code to the link address (8M) |
| * Setup C stack |
| * Initialize UART |
| * Decompress the kernel to 0x0 |
| * Jump to the kernel entry |
| * |
| */ |
| |
| .globl start |
| start: |
| bl start_ |
| #ifdef CONFIG_IBM_OPENBIOS |
| /* The IBM "Tree" bootrom knows that the address of the bootrom |
| * read only structure is 4 bytes after _start. |
| */ |
| .long 0x62726f6d # structure ID - "brom" |
| .long 0x5f726f00 # - "_ro\0" |
| .long 1 # structure version |
| .long bootrom_cmdline # address of *bootrom_cmdline |
| #endif |
| |
| start_: |
| #ifdef CONFIG_FORCE |
| /* We have some really bad firmware. We must disable the L1 |
| * icache/dcache now or the board won't boot. |
| */ |
| li r4,0x0000 |
| isync |
| mtspr SPRN_HID0,r4 |
| sync |
| isync |
| #endif |
| |
| #if defined(CONFIG_MBX) || defined(CONFIG_RPX8260) || defined(CONFIG_PPC_PREP) |
| mr r29,r3 /* On the MBX860, r3 is the board info pointer. |
| * On the RPXSUPER, r3 points to the NVRAM |
| * configuration keys. |
| * On PReP, r3 is the pointer to the residual data. |
| */ |
| #endif |
| |
| #if defined(CONFIG_XILINX_VIRTEX_4_FX) |
| /* PPC errata 213: only for Virtex-4 FX */ |
| mfccr0 0 |
| oris 0,0,0x50000000@h |
| mtccr0 0 |
| #endif |
| |
| mflr r3 /* Save our actual starting address. */ |
| |
| /* The following functions we call must not modify r3 or r4..... |
| */ |
| #ifdef CONFIG_6xx |
| /* On PReP we must look at the OpenFirmware pointer and sanity |
| * test it. On other platforms, we disable the MMU right now |
| * and other bits. |
| */ |
| #ifdef CONFIG_PPC_PREP |
| /* |
| * Save the OF pointer to r25, but only if the entry point is in a sane |
| * location; if not we store 0. If there is no entry point, or it is |
| * invalid, we establish the default MSR value immediately. Otherwise, |
| * we defer doing that, to allow OF functions to be called, until we |
| * begin uncompressing the kernel. |
| */ |
| lis r8,0x0fff /* r8 = 0x0fffffff */ |
| ori r8,r8,0xffff |
| |
| subc r8,r8,r5 /* r8 = (r5 <= r8) ? ~0 : 0 */ |
| subfe r8,r8,r8 |
| nand r8,r8,r8 |
| |
| and. r5,r5,r8 /* r5 will be cleared if (r5 > r8) */ |
| bne+ haveOF |
| |
| li r8,MSR_IP|MSR_FP /* Not OF: set MSR immediately */ |
| mtmsr r8 |
| isync |
| haveOF: |
| mr r25,r5 |
| #else |
| bl disable_6xx_mmu |
| #endif |
| bl disable_6xx_l1cache |
| |
| CLEAR_CACHES |
| #endif |
| |
| #ifdef CONFIG_8xx |
| mfmsr r8 /* Turn off interrupts */ |
| li r9,0 |
| ori r9,r9,MSR_EE |
| andc r8,r8,r9 |
| mtmsr r8 |
| |
| /* We do this because some boot roms don't initialize the |
| * processor correctly. Don't do this if you want to debug |
| * using a BDM device. |
| */ |
| li r4,0 /* Zero DER to prevent FRZ */ |
| mtspr SPRN_DER,r4 |
| #endif |
| |
| #if defined(CONFIG_MBX) || defined(CONFIG_RPX8260) || defined(CONFIG_PPC_PREP) |
| mr r4,r29 /* put the board info pointer where the relocate |
| * routine will find it |
| */ |
| #endif |
| |
| /* Get the load address. |
| */ |
| subi r3, r3, 4 /* Get the actual IP, not NIP */ |
| b relocate |
| |
