[PATCH 4.0 38/55] ARM: tegra20: Store CPU "resettable" status in IRAM

Greg Kroah-Hartman
2015-07-08T08:07:46Z

From: Dmitry Osipenko <digetx@gmail.com>

commit 4d48edb3c3e1234d6b3fcdfb9ac24d7c6de449cb upstream.

Commit 7232398abc6a ("ARM: tegra: Convert PMC to a driver") changed tegra_resume()
location storing from late to early and, as a result, broke suspend on Tegra20.
PMC scratch register 41 is used by tegra LP1 resume code for retrieving stored
physical memory address of common resume function and in the same time used by
tegra20_cpu_shutdown() (shared by Tegra20 cpuidle driver and platform SMP code),
which is storing CPU1 "resettable" status. It implies strict order of scratch
register usage, otherwise resume function address is lost on Tegra20 after
disabling non-boot CPU's on suspend. Fix it by storing "resettable" status in
IRAM instead of PMC scratch register.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Fixes: 7232398abc6a (ARM: tegra: Convert PMC to a driver)
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/arm/mach-tegra/cpuidle-tegra20.c | 5 +---
arch/arm/mach-tegra/reset-handler.S | 10 ++++++---
arch/arm/mach-tegra/reset.h | 4 +++
arch/arm/mach-tegra/sleep-tegra20.S | 37 +++++++++++++++++++---------------
arch/arm/mach-tegra/sleep.h | 4 +++
5 files changed, 38 insertions(+), 22 deletions(-)

--- a/arch/arm/mach-tegra/cpuidle-tegra20.c
+++ b/arch/arm/mach-tegra/cpuidle-tegra20.c
@@ -35,6 +35,7 @@
#include "iomap.h"
#include "irq.h"
#include "pm.h"
+#include "reset.h"
#include "sleep.h"

#ifdef CONFIG_PM_SLEEP
@@ -71,15 +72,13 @@ static struct cpuidle_driver tegra_idle_

#ifdef CONFIG_PM_SLEEP
#ifdef CONFIG_SMP
-static void __iomem *pmc = IO_ADDRESS(TEGRA_PMC_BASE);
-
static int tegra20_reset_sleeping_cpu_1(void)
{
int ret = 0;

tegra_pen_lock();

- if (readl(pmc + PMC_SCRATCH41) == CPU_RESETTABLE)
+ if (readb(tegra20_cpu1_resettable_status) == CPU_RESETTABLE)
tegra20_cpu_shutdown(1);
else
ret = -EINVAL;
--- a/arch/arm/mach-tegra/reset-handler.S
+++ b/arch/arm/mach-tegra/reset-handler.S
@@ -169,10 +169,10 @@ after_errata:
cmp r6, #TEGRA20
bne 1f
/* If not CPU0, don't let CPU0 reset CPU1 now that CPU1 is coming up. */
- mov32 r5, TEGRA_PMC_BASE
- mov r0, #0
+ mov32 r5, TEGRA_IRAM_BASE + TEGRA_IRAM_RESET_HANDLER_OFFSET
+ mov r0, #CPU_NOT_RESETTABLE
cmp r10, #0
- strne r0, [r5, #PMC_SCRATCH41]
+ strneb r0, [r5, #__tegra20_cpu1_resettable_status_offset]
1:
#endif

@@ -281,6 +281,10 @@ __tegra_cpu_reset_handler_data:
.rept TEGRA_RESET_DATA_SIZE
.long 0
.endr
+ .globl __tegra20_cpu1_resettable_status_offset
+ .equ __tegra20_cpu1_resettable_status_offset, \
+ . - __tegra_cpu_reset_handler_start
+ .byte 0
.align L1_CACHE_SHIFT

ENTRY(__tegra_cpu_reset_handler_end)
--- a/arch/arm/mach-tegra/reset.h
+++ b/arch/arm/mach-tegra/reset.h
@@ -35,6 +35,7 @@ extern unsigned long __tegra_cpu_reset_h

void __tegra_cpu_reset_handler_start(void);
void __tegra_cpu_reset_handler(void);
+void __tegra20_cpu1_resettable_status_offset(void);
void __tegra_cpu_reset_handler_end(void);
void tegra_secondary_startup(void);

@@ -47,6 +48,9 @@ void tegra_secondary_startup(void);
(IO_ADDRESS(TEGRA_IRAM_BASE + TEGRA_IRAM_RESET_HANDLER_OFFSET + \
((u32)&__tegra_cpu_reset_handler_data[TEGRA_RESET_MASK_LP2] - \
(u32)__tegra_cpu_reset_handler_start)))
+#define tegra20_cpu1_resettable_status \
+ (IO_ADDRESS(TEGRA_IRAM_BASE + TEGRA_IRAM_RESET_HANDLER_OFFSET + \
+ (u32)__tegra20_cpu1_resettable_status_offset))
#endif

#define tegra_cpu_reset_handler_offset \
--- a/arch/arm/mach-tegra/sleep-tegra20.S
+++ b/arch/arm/mach-tegra/sleep-tegra20.S
@@ -97,9 +97,10 @@ ENDPROC(tegra20_hotplug_shutdown)
ENTRY(tegra20_cpu_shutdown)
cmp r0, #0
reteq lr @ must not be called for CPU 0
- mov32 r1, TEGRA_PMC_VIRT + PMC_SCRATCH41
+ mov32 r1, TEGRA_IRAM_RESET_BASE_VIRT
+ ldr r2, =__tegra20_cpu1_resettable_status_offset
mov r12, #CPU_RESETTABLE
- str r12, [r1]
+ strb r12, [r1, r2]

cpu_to_halt_reg r1, r0
ldr r3, =TEGRA_FLOW_CTRL_VIRT
@@ -182,38 +183,41 @@ ENDPROC(tegra_pen_unlock)
/*
* tegra20_cpu_clear_resettable(void)
*
- * Called to clear the "resettable soon" flag in PMC_SCRATCH41 when
+ * Called to clear the "resettable soon" flag in IRAM variable when
* it is expected that the secondary CPU will be idle soon.
*/
ENTRY(tegra20_cpu_clear_resettable)
- mov32 r1, TEGRA_PMC_VIRT + PMC_SCRATCH41
+ mov32 r1, TEGRA_IRAM_RESET_BASE_VIRT
+ ldr r2, =__tegra20_cpu1_resettable_status_offset
mov r12, #CPU_NOT_RESETTABLE
- str r12, [r1]
+ strb r12, [r1, r2]
ret lr
ENDPROC(tegra20_cpu_clear_resettable)

/*
* tegra20_cpu_set_resettable_soon(void)
*
- * Called to set the "resettable soon" flag in PMC_SCRATCH41 when
+ * Called to set the "resettable soon" flag in IRAM variable when
* it is expected that the secondary CPU will be idle soon.
*/
ENTRY(tegra20_cpu_set_resettable_soon)
- mov32 r1, TEGRA_PMC_VIRT + PMC_SCRATCH41
+ mov32 r1, TEGRA_IRAM_RESET_BASE_VIRT
+ ldr r2, =__tegra20_cpu1_resettable_status_offset
mov r12, #CPU_RESETTABLE_SOON
- str r12, [r1]
+ strb r12, [r1, r2]
ret lr
ENDPROC(tegra20_cpu_set_resettable_soon)

/*
* tegra20_cpu_is_resettable_soon(void)
*
- * Returns true if the "resettable soon" flag in PMC_SCRATCH41 has been
+ * Returns true if the "resettable soon" flag in IRAM variable has been
* set because it is expected that the secondary CPU will be idle soon.
*/
ENTRY(tegra20_cpu_is_resettable_soon)
- mov32 r1, TEGRA_PMC_VIRT + PMC_SCRATCH41
- ldr r12, [r1]
+ mov32 r1, TEGRA_IRAM_RESET_BASE_VIRT
+ ldr r2, =__tegra20_cpu1_resettable_status_offset
+ ldrb r12, [r1, r2]
cmp r12, #CPU_RESETTABLE_SOON
moveq r0, #1
movne r0, #0
@@ -256,9 +260,10 @@ ENTRY(tegra20_sleep_cpu_secondary_finish
mov r0, #TEGRA_FLUSH_CACHE_LOUIS
bl tegra_disable_clean_inv_dcache

- mov32 r0, TEGRA_PMC_VIRT + PMC_SCRATCH41
+ mov32 r0, TEGRA_IRAM_RESET_BASE_VIRT
+ ldr r4, =__tegra20_cpu1_resettable_status_offset
mov r3, #CPU_RESETTABLE
- str r3, [r0]
+ strb r3, [r0, r4]

bl tegra_cpu_do_idle

@@ -274,10 +279,10 @@ ENTRY(tegra20_sleep_cpu_secondary_finish

bl tegra_pen_lock

- mov32 r3, TEGRA_PMC_VIRT
- add r0, r3, #PMC_SCRATCH41
+ mov32 r0, TEGRA_IRAM_RESET_BASE_VIRT
+ ldr r4, =__tegra20_cpu1_resettable_status_offset
mov r3, #CPU_NOT_RESETTABLE
- str r3, [r0]
+ strb r3, [r0, r4]

bl tegra_pen_unlock

--- a/arch/arm/mach-tegra/sleep.h
+++ b/arch/arm/mach-tegra/sleep.h
@@ -18,6 +18,7 @@
#define __MACH_TEGRA_SLEEP_H

#include "iomap.h"
+#include "irammap.h"

#define TEGRA_ARM_PERIF_VIRT (TEGRA_ARM_PERIF_BASE - IO_CPU_PHYS \
+ IO_CPU_VIRT)
@@ -29,6 +30,9 @@
+ IO_APB_VIRT)
#define TEGRA_PMC_VIRT (TEGRA_PMC_BASE - IO_APB_PHYS + IO_APB_VIRT)

+#define TEGRA_IRAM_RESET_BASE_VIRT (IO_IRAM_VIRT + \
+ TEGRA_IRAM_RESET_HANDLER_OFFSET)
+
/* PMC_SCRATCH37-39 and 41 are used for tegra_pen_lock and idle */
#define PMC_SCRATCH37 0x130
#define PMC_SCRATCH38 0x134