Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux

ARM: 5884/1: arm: Fix DCC console for v7

Without this patch arch/arm/compressed/head.S defaults to generic
DCC code that does not work for v7.

For more information on the v7 DCC, see Cortex-A8 TRM
"12.11.1 Debug communications channel".

To use it with post 2.6.33-rc1 or later, you need to have:

CONFIG_DEBUG_LL=y
ONFIG_DEBUG_ICEDCC=y
CONFIG_EARLY_PRINTK=y

Earlier kernels need commit 93fd03a8c6728b58879f8af20ffd55d9c32a778b
backported.

Tested on omap3430.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

authored by

Tony Lindgren and committed by
Russell King
200b7a8d a7b22962

+40
+8
arch/arm/boot/compressed/head.S
··· 27 27 .macro writeb, ch, rb 28 28 mcr p14, 0, \ch, c0, c5, 0 29 29 .endm 30 + #elif defined(CONFIG_CPU_V7) 31 + .macro loadsp, rb 32 + .endm 33 + .macro writeb, ch, rb 34 + wait: mrc p14, 0, pc, c0, c1, 0 35 + bcs wait 36 + mcr p14, 0, \ch, c0, c5, 0 37 + .endm 30 38 #elif defined(CONFIG_CPU_XSCALE) 31 39 .macro loadsp, rb 32 40 .endm
+12
arch/arm/boot/compressed/misc.c
··· 53 53 54 54 asm("mcr p14, 0, %0, c0, c5, 0" : : "r" (ch)); 55 55 } 56 + 57 + #elif defined(CONFIG_CPU_V7) 58 + 59 + static void icedcc_putc(int ch) 60 + { 61 + asm( 62 + "wait: mrc p14, 0, pc, c0, c1, 0 \n\ 63 + bcs wait \n\ 64 + mcr p14, 0, %0, c0, c5, 0 " 65 + : : "r" (ch)); 66 + } 67 + 56 68 #elif defined(CONFIG_CPU_XSCALE) 57 69 58 70 static void icedcc_putc(int ch)
+20
arch/arm/kernel/debug.S
··· 49 49 1002: 50 50 .endm 51 51 52 + #elif defined(CONFIG_CPU_V7) 53 + 54 + .macro addruart, rx 55 + .endm 56 + 57 + .macro senduart, rd, rx 58 + mcr p14, 0, \rd, c0, c5, 0 59 + .endm 60 + 61 + .macro busyuart, rd, rx 62 + busy: mrc p14, 0, pc, c0, c1, 0 63 + bcs busy 64 + .endm 65 + 66 + .macro waituart, rd, rx 67 + wait: mrc p14, 0, pc, c0, c1, 0 68 + bcs wait 69 + 70 + .endm 71 + 52 72 #elif defined(CONFIG_CPU_XSCALE) 53 73 54 74 .macro addruart, rx