ARM: v7 setup function should invalidate L1 cache

All ARMv5 and older CPUs invalidate their caches in the early assembly
setup function, prior to enabling the MMU.  This is because the L1
cache should not contain any data relevant to the execution of the
kernel at this point; all data should have been flushed out to memory.

This requirement should also be true for ARMv6 and ARMv7 CPUs - indeed,
these typically do not search their caches when caching is disabled (as
it needs to be when the MMU is disabled) so this change should be safe.

ARMv7 allows there to be CPUs which search their caches while caching is
disabled, and it's permitted that the cache is uninitialised at boot;
for these, the architecture reference manual requires that an
implementation specific code sequence is used immediately after reset
to ensure that the cache is placed into a sane state.  Such
functionality is definitely outside the remit of the Linux kernel, and
must be done by the SoC's firmware before _any_ CPU gets to the Linux
kernel.

Changing the data cache clean+invalidate to a mere invalidate allows us
to get rid of a lot of platform specific hacks around this issue for
their secondary CPU bringup paths - some of which were buggy.

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Dinh Nguyen <dinguyen@opensource.altera.com>
Acked-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Tested-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Thierry Reding <treding@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Michal Simek <michal.simek@xilinx.com>
Tested-by: Wei Xu <xuwei5@hisilicon.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

4 files changed, 2 insertions, 15 deletions

diff --git a/arch/arm/mach-tegra/Makefile b/arch/arm/mach-tegra/Makefile
index e48a74458c25..fffad2426ee4 100644
--- a/arch/arm/mach-tegra/Makefile
+++ b/arch/arm/mach-tegra/Makefile
@@ -19,7 +19,7 @@ obj-$(CONFIG_ARCH_TEGRA_3x_SOC)		+= pm-tegra30.o
 ifeq ($(CONFIG_CPU_IDLE),y)
 obj-$(CONFIG_ARCH_TEGRA_3x_SOC)		+= cpuidle-tegra30.o
 endif
-obj-$(CONFIG_SMP)			+= platsmp.o headsmp.o
+obj-$(CONFIG_SMP)			+= platsmp.o
 obj-$(CONFIG_HOTPLUG_CPU)               += hotplug.o
 
 obj-$(CONFIG_ARCH_TEGRA_114_SOC)	+= sleep-tegra30.o
diff --git a/arch/arm/mach-tegra/headsmp.S b/arch/arm/mach-tegra/headsmp.S
deleted file mode 100644
index 2072e7322c39..000000000000
--- a/arch/arm/mach-tegra/headsmp.S
+++ /dev/null
@@ -1,12 +0,0 @@
-#include <linux/linkage.h>
-#include <linux/init.h>
-
-#include "sleep.h"
-
-        .section ".text.head", "ax"
-
-ENTRY(tegra_secondary_startup)
-        check_cpu_part_num 0xc09, r8, r9
-        bleq    v7_invalidate_l1
-        b       secondary_startup
-ENDPROC(tegra_secondary_startup)
diff --git a/arch/arm/mach-tegra/reset.c b/arch/arm/mach-tegra/reset.c
index 894c5c472184..6fd9db54887e 100644
--- a/arch/arm/mach-tegra/reset.c
+++ b/arch/arm/mach-tegra/reset.c
@@ -94,7 +94,7 @@ void __init tegra_cpu_reset_handler_init(void)
 	__tegra_cpu_reset_handler_data[TEGRA_RESET_MASK_PRESENT] =
 		*((u32 *)cpu_possible_mask);
 	__tegra_cpu_reset_handler_data[TEGRA_RESET_STARTUP_SECONDARY] =
-		virt_to_phys((void *)tegra_secondary_startup);
+		virt_to_phys((void *)secondary_startup);
 #endif
 
 #ifdef CONFIG_PM_SLEEP
diff --git a/arch/arm/mach-tegra/reset.h b/arch/arm/mach-tegra/reset.h
index 76a93434c6ee..0aee0129f8d7 100644
--- a/arch/arm/mach-tegra/reset.h
+++ b/arch/arm/mach-tegra/reset.h
@@ -36,7 +36,6 @@ extern unsigned long __tegra_cpu_reset_handler_data[TEGRA_RESET_DATA_SIZE];
 void __tegra_cpu_reset_handler_start(void);
 void __tegra_cpu_reset_handler(void);
 void __tegra_cpu_reset_handler_end(void);
-void tegra_secondary_startup(void);
 
 #ifdef CONFIG_PM_SLEEP
 #define tegra_cpu_lp1_mask \