diff options
Diffstat (limited to 'cpu/blackfin/start.S')
| -rw-r--r-- | cpu/blackfin/start.S | 83 |
1 files changed, 50 insertions, 33 deletions
diff --git a/cpu/blackfin/start.S b/cpu/blackfin/start.S index 6c8def4..506fea5 100644 --- a/cpu/blackfin/start.S +++ b/cpu/blackfin/start.S @@ -95,36 +95,64 @@ ENTRY(_start) /* 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 ... + /* Figure out where we are currently executing so that we can decide + * how to best reprogram and relocate things. We'll pass below: + * R4: load address of _start + * R5: current (not load) address of _start */ + serial_early_puts("Find ourselves"); + call _get_pc; - r3 = 0x0; - r3.h = 0x2000; - cc = r0 < r3 (iu); - if cc jump .Lproc_initialized; +.Loffset: + r1.l = .Loffset; + r1.h = .Loffset; + r4.l = _start; + r4.h = _start; + r3 = r1 - r4; + r5 = r0 - r3; + + /* 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); + cc = r4 == r5; + if cc jump .Lnorelocate; + r6 = 0 (x); + /* 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, memory, and setup our async banks. + */ serial_early_puts("Program Clocks"); + /* if we're executing >=0x20000000, then we dont need to dma */ + r3 = 0x0; + r3.h = 0x2000; + cc = r5 < r3 (iu); + if cc jump .Ldma_and_reprogram; call _initcode; + jump .Lprogrammed; + + /* we're sitting in external memory, so dma into L1 and reprogram */ +.Ldma_and_reprogram: + r0.l = LO(L1_INST_SRAM); + r0.h = HI(L1_INST_SRAM); + r1.l = __initcode_start; + r1.h = __initcode_start; + r2.l = __initcode_end; + r2.h = __initcode_end; + r2 = r2 - r1; /* convert r2 into length of initcode */ + r1 = r1 - r4; /* convert r1 from load address of initcode ... */ + r1 = r1 + r5; /* ... to current (not load) address of initcode */ + p3 = r0; + call _dma_memcpy_nocache; + call (p3); /* Since we reprogrammed SCLK, we need to update the serial divisor */ +.Lprogrammed: 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 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 @@ -132,19 +160,8 @@ ENTRY(_start) * it yet (see "lower to 15" below). */ serial_early_puts("Relocate"); - call _get_pc; -.Loffset: - r2.l = .Loffset; - r2.h = .Loffset; - r3.l = _start; - r3.h = _start; - r2 = r2 - r3; - r1 = r0 - r2; - cc = r1 == r3; - if cc jump .Lnorelocate; - r6 = 0 (x); - - r0 = r3; + r0 = r4; + r1 = r5; r2.l = LO(CONFIG_SYS_MONITOR_LEN); r2.h = HI(CONFIG_SYS_MONITOR_LEN); call _memcpy_ASM; |