diff options
Diffstat (limited to 'firmware/target/arm/s3c2440/crt0.S')
| -rw-r--r-- | firmware/target/arm/s3c2440/crt0.S | 120 |
1 files changed, 65 insertions, 55 deletions
diff --git a/firmware/target/arm/s3c2440/crt0.S b/firmware/target/arm/s3c2440/crt0.S index e916cafe40..ff5eafd042 100644 --- a/firmware/target/arm/s3c2440/crt0.S +++ b/firmware/target/arm/s3c2440/crt0.S @@ -9,7 +9,8 @@ * * Copyright (C) 2008 by Karl Kurbjun * - * Arm bootloader and startup code based on startup.s from the iPodLinux loader + * Arm bootloader and startup code based on startup.s from the iPodLinux + * loader * Copyright (c) 2003, Daniel Palffy (dpalffy (at) rainstorm.org) * Copyright (c) 2005, Bernard Leach <leachbj@bouncycastle.org> * @@ -41,12 +42,12 @@ vectors: b fiq_handler /* This branch is used to make sure that we know where the shutdown routine - * is located in flash (0x04000020) + * is located in flash (0x040A0020) */ b rom_shutdown /* Add some strings to detect the bootloader in flash and give it a version - * number. (0x04000024, 0x04000028) + * number. (0x040A0028, 0x040A002C) */ .string "ROCKBOX" .word 0x0001 @@ -80,10 +81,56 @@ word_copy: .section .init.text,"ax",%progbits .code 32 -.align 0x04 /* Align */ +.align 0x04 .global start start: - msr cpsr, #0xd3 /* enter supervisor mode, disable IRQ */ + + /* Get the execute address; R0 is used to store the address and it should + * not be written to till the rest of the execution checks are done below. + * This is done first thing since we have to check if the code was started + * with the old rockbox bootloader that offset the image by 100 bytes. + */ + ldr r0, =0xffffff00 + and r0, pc, r0 + + /************************** DO NOT WRITE TO R0 ***************************/ + + /* Check if the code is running from flash. If not skip all these checks */ + cmp r0, #0xA0000 + bne poweron + + /* Set GPG up to read power and menu status */ + ldr r2, =0x56000050 + ldr r1, [r2, #0x18] + orr r1, r1, #0x03 + str r1, [r2, #0x18] + + /* Check if menu is held down */ + ldr r1, [r2, #0x14] + ands r3, r1, #0x02 + bne bootOF + + /* Check if power is held down */ + ands r3, r1, #0x01 + bne poweron + + /* Set GPF up to read charger connection if power is not held down */ + ldr r1, [r2, #0x08] + orr r1, r1, #0x10 + str r1, [r2, #0x08] + + /* Check if charger is connected */ + ldr r1, [r2, #0x04] + ands r1, r1, #0x10 + beq poweron + +bootOF: + /* power is not down || menu is held || the charger is not connected */ + mov pc, #0x70 + +poweron: + /* enter supervisor mode, disable IRQ */ + msr cpsr, #0xd3 /* Disable the watchdog */ ldr r2, =0x00000000 @@ -100,17 +147,11 @@ start: str r2, [r1, #0x1C] /* Check if loaded by the old bootloader or by the OF. This copy routine - * cannot run/copy properly until the memory has been initialized, so the copy - * routine later is still necessary. The old bootloader/OF will initialize the - * memory. - * Be careful with code size above this as well since this routine has to start - * before 0x100 for it to work right. + * cannot run/copy properly until the memory has been initialized, so the + * copy routine later is still necessary. The old bootloader/OF will + * initialize the memory. */ - /* Get the execute address (cannot be past 0x100 for this to work */ - ldr r0, =0xffffff00 - and r0, pc, r0 - /* Calculate the length of the code needed to run/copy */ ldr r1, = _vectorstart ldr r2, = _initdata_end @@ -124,19 +165,21 @@ start: /* There's enough space, skip copying */ bgt skipreset - /* Is this code running from 0x0? If so skip copy. */ - cmplt r0, #0 + /* Is this code running from 0xA0000? If so skip copy. */ + cmplt r0, #0xA0000 beq skipreset + + /****************************** OK TO USE R0 *****************************/ - /* There's not enough space to copy without overwriting, copy to safe spot - * and reset + /* There's not enough space to copy without overwriting, copy to safe + * spot and reset */ mov r1, #0x31000000 /* copy location */ bl word_copy mov pc, #0x31000000 - skipreset: +skipreset: /* Initial Clock Setup */ /* set Bus to Asynchronous mode (full speed) */ @@ -319,39 +362,6 @@ start: ldr r2, =0x00FFFFFF str r2, [r1] -#if 0 - /* GPACON */ - mov r1, #0x56000000 - ldr r2, =0x01FFFCFF /* 0x01FFFCFF */ - str r2, [r1] - - /* GPADAT */ - ldr r2, =0x01FFFEFF - str r2, [r1, #0x04] - - /* MRSRB6 */ - mov r1, #0x48000000 - mov r2, #0x00000000 - str r2, [r1, #0x2C] - - /* GPADAT */ - mov r1, #0x56000000 - ldr r2, =0x01FFFFFF - str r2, [r1, #0x04] - - /* MRSRB6 */ - mov r1, #0x48000000 - mov r2, #0x00000030 - str r2, [r1, #0x2C] - - /* GPACON */ - mov r1, #0x56000000 - mov r2, #0x01FFFFFF - str r2, [r1] - - /* End of the unknown */ -#endif - /* The builds have two potential load addresses, one being from flash, * and the other from some "unknown" location right now the assumption * is that the code is not at 0x3000000. @@ -373,7 +383,7 @@ start: ldr r1, =donecopy ldr r2, =0x30000000 add r1, r1, r2 - mov pc, r1 /* The code is located where we want it-jump*/ + mov pc, r1 /* The code is located where we want it so jump */ donecopy: @@ -444,7 +454,7 @@ stackmunge: /* Start the main function */ ldr pc, =main - /* Should never get here, but let's restart in case (also needed when + /* Should never get here, but let's restart in case (also needed for * linking) */ b vectors @@ -600,7 +610,7 @@ rom_shutdown: ldr r2, [lr] // str r2, [r11,#-0x28] ldr r3, [r0] - Orr r3, r3, #0x00400000 + orr r3, r3, #0x00C00000 /* REFRESH * [22] TREFMD - SDRAM Refresh Mode */ |