Many arm926ejs-based SoCs boot at 0xffff0000. Currently these last 64 KB of flash are wasted just for a jump to the location where u-boot was flashed. This commit provides split relocation where the first part of u-boot is stored from the reset address to the end of the flash, and the second part is stored below the first one. This allows booting directly into _start at 0xffff0000, thus fully using the last flash sector. For the ED Mini V2, this frees 12.5% of the flash for other uses.
Signed-off-by: Albert Aribaud albert.aribaud@free.fr --- As indicated in the subject line, this patch is *not* a bugfix and thus *not* expected to be integrated into 2010.09.
It was heavily tested on an ED Mini V2 and a 5Big Network. All the following cases were debugged step by step through JTAG:
- boot from RAM (with relocation, without low level init) - boot from linear image in FLASH (with reloc & ll init) - boot from split image in FLASH (with reloc & ll init)
'checkpatch.pl --no-tree' reported 0 errors and warnings.
arch/arm/cpu/arm926ejs/start.S | 81 +++++++++++++++++++++++++++++++++------ 1 files changed, 68 insertions(+), 13 deletions(-)
diff --git a/arch/arm/cpu/arm926ejs/start.S b/arch/arm/cpu/arm926ejs/start.S index cf40ce1..9a0a9ef 100644 --- a/arch/arm/cpu/arm926ejs/start.S +++ b/arch/arm/cpu/arm926ejs/start.S @@ -5,8 +5,8 @@ * * ----- Adapted for OMAP1610 OMAP730 from ARM925t code ------ * - * Copyright (c) 2001 Marius Gröger mag@sysgo.de - * Copyright (c) 2002 Alex Züpke azu@sysgo.de + * Copyright (c) 2001 Marius Gröger mag@sysgo.de + * Copyright (c) 2002 Alex ZÃŒpke azu@sysgo.de * Copyright (c) 2002 Gary Jennejohn garyj@denx.de * Copyright (c) 2003 Richard Woodruff r-woodruff2@ti.com * Copyright (c) 2003 Kshitij kshitij@ti.com @@ -166,21 +166,74 @@ reset: bl cpu_init_crit #endif
+/* + * This code copies SIZE bytes of u-boot from 'source' _start (in FLASH) + * to 'destination' _TEXT_BASE (in RAM) RAM. It can handle two cases: + * + * 1) source is entirely located at [_start,_start+_bss_start-_armboot_start[ + * i.e. u-boot.bin was linearly written to FLASH (this is the case when + * the target's reset vector can be _start, or points to some code which + * will eventually jump inside FLASH to _start) + * + * 2) source was split in two parts, one located at [_start,0x1.0000.0000[ + * (for SIZE1 bytes where SIZE1 = (0x1.0000.000 - _start) and one located + * at [_start-A, SIZE-SIZE1[ where A = (_bss_start-_armboot_start) rounded + * up to the nearest multiple of SIZE1. This is the case when the target's + * reset vector must point directly to _start but there is not enough room + * between _start and the end of the 32-bit addressable FLASH. + * + * Example for the Orion5x 88F5182, which resets at 0xFFFF0000, and with an + * overall u-boot size of 0x0001CAFE: + * - the first 64 KB of u-boot.bin are flashed at [0xFFFF0000, 0x100000000[; + * - there are 0xCAFE bytes left, which take up one 64KB block. The second + * part of u-boot will thus be flashed at [0xfffE0000, 0xfffECAFE[. + * + * To determine if the copy must be split, we taken the start addresse + * of the source and add the source length to it to form the end address. + * if this end address is below the start address, then the image was split. + * If it is above the start address, the image was not split. + */ + #ifndef CONFIG_SKIP_RELOCATE_UBOOT -relocate: /* relocate U-Boot to RAM */ + /* relocate U-Boot to RAM */ +relocate: + /* skip copy if source == destination */ adr r0, _start /* r0 <- current position of code */ ldr r1, _TEXT_BASE /* test if we run from flash or RAM */ cmp r0, r1 /* don't reloc during debug */ beq stack_setup + + /* skip split copying if copy is split */ ldr r2, _armboot_start ldr r3, _bss_start - sub r2, r3, r2 /* r2 <- size of armboot */ - add r2, r0, r2 /* r2 <- source end address */ + sub r4, r3, r2 /* r4 <- size of armboot */ + add r2, r0, r4 /* r2 <- source end address */ + cmp r2, r0 /* does the source rollover? */ + bhi copy_loop /* no: copy is linear, go do it. */ + + /* block size is 0x1.0000.0000 - _start */ + rsb r3, r0, #0 + + /* round u-boot size up to the nearest multiple of block size */ + sub r3, r3, #1 + orr r4, r4, r3 + add r4, r4, #1 + + /* copy second part, end condition is r0 rollover to 0 */ +copy_second: + ldmia r0!, {r5-r12} /* copy from source address [r0] */ + stmia r1!, {r5-r12} /* copy to target address [r1] */ + cmp r0, #0 /* until source end address [#0] */ + bne copy_second + + /* move source start and end back by the u-boot size rounded up */ + sub r0, r0, r4 /* r0 <- source address of 2nd part */ + sub r2, r2, r4 /* r2 <- source end adr of 2nd part */
copy_loop: - ldmia r0!, {r3-r10} /* copy from source address [r0] */ - stmia r1!, {r3-r10} /* copy to target address [r1] */ - cmp r0, r2 /* until source end addreee [r2] */ + ldmia r0!, {r5-r12} /* copy from source address [r0] */ + stmia r1!, {r5-r12} /* copy to target address [r1] */ + cmp r0, r2 /* until source end address [r2] */ ble copy_loop #endif /* CONFIG_SKIP_RELOCATE_UBOOT */
@@ -189,14 +242,14 @@ stack_setup: ldr r0, _TEXT_BASE /* upper 128 KiB: relocated uboot */ sub sp, r0, #128 /* leave 32 words for abort-stack */ #ifndef CONFIG_PRELOADER - sub r0, r0, #CONFIG_SYS_MALLOC_LEN /* malloc area */ - sub r0, r0, #CONFIG_SYS_GBL_DATA_SIZE /* bdinfo */ + sub r0, r0, #CONFIG_SYS_MALLOC_LEN /* malloc area */ + sub r0, r0, #CONFIG_SYS_GBL_DATA_SIZE /* bdinfo */ #ifdef CONFIG_USE_IRQ sub r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ) #endif #endif /* CONFIG_PRELOADER */ sub sp, r0, #12 /* leave 3 words for abort-stack */ - bic sp, sp, #7 /* 8-byte alignment for ABI compliance */ + bic sp, sp, #7 /* ABI-compliant 8-bit alignment */
clear_bss: ldr r0, _bss_start /* find start of bss segment */ @@ -310,7 +363,8 @@ cpu_init_crit:
ldr r2, _armboot_start sub r2, r2, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN) - sub r2, r2, #(CONFIG_SYS_GBL_DATA_SIZE+8) @ set base 2 words into abort stack + @ reserve a couple spots in abort stack + sub r2, r2, #(CONFIG_SYS_GBL_DATA_SIZE+8) @ get values for "aborted" pc and cpsr (into parm regs) ldmia r2, {r2 - r3} add r0, sp, #S_FRAME_SIZE @ grab pointer to old stack @@ -344,7 +398,8 @@ cpu_init_crit: .macro get_bad_stack ldr r13, _armboot_start @ setup our mode stack sub r13, r13, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN) - sub r13, r13, #(CONFIG_SYS_GBL_DATA_SIZE+8) @ reserved a couple spots in abort stack + @ reserve a couple spots in abort stack + sub r13, r13, #(CONFIG_SYS_GBL_DATA_SIZE+8)
str lr, [r13] @ save caller lr in position 0 of saved stack mrs lr, spsr @ get the spsr