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@xxxxxxxxxxx>
---
arch/arm/boot/compressed/head.S | 8 ++++++++
arch/arm/boot/compressed/misc.c | 12 ++++++++++++
arch/arm/kernel/debug.S | 20 ++++++++++++++++++++
3 files changed, 40 insertions(+), 0 deletions(-)
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index d356af7..4fddc50 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -27,6 +27,14 @@
.macro writeb, ch, rb
mcr p14, 0, \ch, c0, c5, 0
.endm
+#elif defined(CONFIG_CPU_V7)
+ .macro loadsp, rb
+ .endm
+ .macro writeb, ch, rb
+wait: mrc p14, 0, pc, c0, c1, 0
+ bcs wait
+ mcr p14, 0, \ch, c0, c5, 0
+ .endm
#elif defined(CONFIG_CPU_XSCALE)
.macro loadsp, rb
.endm
diff --git a/arch/arm/boot/compressed/misc.c b/arch/arm/boot/compressed/misc.c
index 17153b5..2d1e819 100644
--- a/arch/arm/boot/compressed/misc.c
+++ b/arch/arm/boot/compressed/misc.c
@@ -48,6 +48,18 @@ static void icedcc_putc(int ch)
asm("mcr p14, 0, %0, c0, c5, 0" : : "r" (ch));
}
+
+#elif defined(CONFIG_CPU_V7)
+
+static void icedcc_putc(int ch)
+{
+ asm(
+ "wait: mrc p14, 0, pc, c0, c1, 0 \n\
+ bcs wait \n\
+ mcr p14, 0, %0, c0, c5, 0 "
+ : : "r" (ch));
+}
+
#elif defined(CONFIG_CPU_XSCALE)
static void icedcc_putc(int ch)
diff --git a/arch/arm/kernel/debug.S b/arch/arm/kernel/debug.S
index b121b60..5c91add 100644
--- a/arch/arm/kernel/debug.S
+++ b/arch/arm/kernel/debug.S
@@ -49,6 +49,26 @@
1002:
.endm
+#elif defined(CONFIG_CPU_V7)
+
+ .macro addruart, rx
+ .endm
+
+ .macro senduart, rd, rx
+ mcr p14, 0, \rd, c0, c5, 0
+ .endm
+
+ .macro busyuart, rd, rx
+busy: mrc p14, 0, pc, c0, c1, 0
+ bcs busy
+ .endm
+
+ .macro waituart, rd, rx
+wait: mrc p14, 0, pc, c0, c1, 0
+ bcs wait
+
+ .endm
+
#elif defined(CONFIG_CPU_XSCALE)
.macro addruart, rx
--
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