[PATCH 228/270] ARM: at91: at91sam9g10: fix SOC type detection

Herton Ronaldo Krzesinski herton.krzesinski at canonical.com
Mon Nov 26 16:58:38 UTC 2012

3.5.7u1 -stable review patch.  If anyone has any objections, please let me know.


From: Ivan Shugov <ivan.shugov at gmail.com>

commit 3d9a0183dd3423353e9e363bcc261c1220d05f9f upstream.

Newer at91sam9g10 SoC revision can't be detected, so the kernel can't boot with
this kind of kernel panic:
"AT91: Impossible to detect the SOC type"

CPU: ARM926EJ-S [41069265] revision 5 (ARMv5TEJ), cr=00053177
CPU: VIVT data cache, VIVT instruction cache
Machine: Atmel AT91SAM9G10-EK
Ignoring tag cmdline (using the default kernel command line)
bootconsole [earlycon0] enabled
Memory policy: ECC disabled, Data cache writeback
Kernel panic - not syncing: AT91: Impossible to detect the SOC type
[<c00133d4>] (unwind_backtrace+0x0/0xe0) from [<c02366dc>] (panic+0x78/0x1cc)
[<c02366dc>] (panic+0x78/0x1cc) from [<c02fa35c>] (at91_map_io+0x90/0xc8)
[<c02fa35c>] (at91_map_io+0x90/0xc8) from [<c02f9860>] (paging_init+0x564/0x6d0)
[<c02f9860>] (paging_init+0x564/0x6d0) from [<c02f7914>] (setup_arch+0x464/0x704)
[<c02f7914>] (setup_arch+0x464/0x704) from [<c02f44f8>] (start_kernel+0x6c/0x2d4)
[<c02f44f8>] (start_kernel+0x6c/0x2d4) from [<20008040>] (0x20008040)

The reason for this is that the Debug Unit Chip ID Register has changed between
Engineering Sample and definitive revision of the SoC. Changing the check of
cidr to socid will address the problem. We do not integrate this check to the
list just above because we also have to make sure that the extended id is

Signed-off-by: Ivan Shugov <ivan.shugov at gmail.com>
[nicolas.ferre at atmel.com: change commit message]
Signed-off-by: Nicolas Ferre <nicolas.ferre at atmel.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
 arch/arm/mach-at91/setup.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/mach-at91/setup.c b/arch/arm/mach-at91/setup.c
index 944bffb..31bb13d 100644
--- a/arch/arm/mach-at91/setup.c
+++ b/arch/arm/mach-at91/setup.c
@@ -151,7 +151,7 @@ static void __init soc_detect(u32 dbgu_base)
 	/* at91sam9g10 */
-	if ((cidr & ~AT91_CIDR_EXT) == ARCH_ID_AT91SAM9G10) {
+	if ((socid & ~AT91_CIDR_EXT) == ARCH_ID_AT91SAM9G10) {
 		at91_soc_initdata.type = AT91_SOC_SAM9G10;
 		at91_boot_soc = at91sam9261_soc;

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