ARM: tegra20: Store CPU "resettable" status in IRAM

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)
Cc: <stable@vger.kernel.org> # v3.17+
Signed-off-by: Thierry Reding <treding@nvidia.com>

5 files changed, 38 insertions, 22 deletions

diff --git a/arch/arm/mach-tegra/cpuidle-tegra20.c b/arch/arm/mach-tegra/cpuidle-tegra20.c
index 88de2dce2e87..7469347b1749 100644
--- a/arch/arm/mach-tegra/cpuidle-tegra20.c
+++ b/arch/arm/mach-tegra/cpuidle-tegra20.c
@@ -34,6 +34,7 @@
 #include "iomap.h"
 #include "irq.h"
 #include "pm.h"
+#include "reset.h"
 #include "sleep.h"
 
 #ifdef CONFIG_PM_SLEEP
@@ -70,15 +71,13 @@ static struct cpuidle_driver tegra_idle_driver = {
 
 #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;
diff --git a/arch/arm/mach-tegra/reset-handler.S b/arch/arm/mach-tegra/reset-handler.S
index 71be4af5e975..e3070fdab80b 100644
--- 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)
diff --git a/arch/arm/mach-tegra/reset.h b/arch/arm/mach-tegra/reset.h
index 76a93434c6ee..29c3dec0126a 100644
--- a/arch/arm/mach-tegra/reset.h
+++ b/arch/arm/mach-tegra/reset.h
@@ -35,6 +35,7 @@ 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 __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 \
diff --git a/arch/arm/mach-tegra/sleep-tegra20.S b/arch/arm/mach-tegra/sleep-tegra20.S
index be4bc5f853f5..e6b684e14322 100644
--- 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
 
diff --git a/arch/arm/mach-tegra/sleep.h b/arch/arm/mach-tegra/sleep.h
index 92d46ec1361a..0d59360d891d 100644
--- 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