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ARM: shmobile: Do additional settings for L2shutdown mode

RFC PATCH Superseded Khiem Nguyen 2 participants 3 messages Sep 26, 2014

Subsystems (4)
Arm (32-bit) Arm sub-architectures SuperH Arm/RISC-V/Renesas architecture

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Khiem Nguyen

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#0 lore raw

RFC PATCH 6/7 ARM: shmobile: Do additional settings for L2shutdown mode

According to Cortex-A15 TRM, some additional settings are needed. Although the procedure was not completely same as in TRM, it was referred to vexpress implementation to arrange order of additional settings.

Signed-off-by Khiem Nguyen <[email protected]>
---
 arch/arm/mach-shmobile/platsmp-apmu.c |   25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
arch/arm/mach-shmobile/platsmp-apmu.c +25 -0
index dfa8a18..0dedb13 100644
@@ -161,8 +161,32 @@ int shmobile_smp_apmu_boot_secondary(unsigned int cpu, struct task_struct *idle)
 
 #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_SUSPEND) || \
 defined(CONFIG_CPU_IDLE)
+static void do_l2shutdown_settings(void)
+{
+	unsigned int v;
+
+	/* Disable L2$ prefetches */
+	asm volatile(
+	"       mrc     p15, 1, %0, c15, c0, 3\n"
+	"       orr     %0, %0, %1\n"
+	"       mcr     p15, 1, %0, c15, c0, 3\n"
+		: "=&r" (v)
+		: "Ir" (0x400)
+		: "cc");
+	isb();
+	dsb();
+
+	flush_cache_all();
+
+	/* Set Double lock control bit */
+	__asm__ __volatile__("mcr p14, 0, %0, c1, c3, 4" : : "r" (0x1));
+}
+
 static inline void cpu_enter_lowpower_a15(void)
 {
+	if (is_a15_l2shutdown)
+		do_l2shutdown_settings();
+
 	v7_exit_coherency_flush(louis);
 }
 

@@ -245,6 +269,7 @@ static int shmobile_smp_apmu_enter_suspend(suspend_state_t state)
 
 	writel_relaxed(0x0, cpucmcr);
 	rcar_sysc_clear_event_status();
+	is_a15_l2shutdown = 0;
 
 	return 0;
 }
Signature · 1 line
1.7.9.5
#1 lore raw

Hi Khiem-san,

Quoted 48 lines · Khiem Nguyen

According to Cortex-A15 TRM, some additional settings are needed. Although the procedure was not completely same as in TRM, it was referred to vexpress implementation to arrange order of additional settings.

Signed-off-by Khiem Nguyen <[email protected]>
---
 arch/arm/mach-shmobile/platsmp-apmu.c |   25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
arch/arm/mach-shmobile/platsmp-apmu.c +24 -0
index dfa8a18..0dedb13 100644
@@ -161,8 +161,32 @@ int shmobile_smp_apmu_boot_secondary(unsigned int cpu, struct task_struct *idle)
 
 #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_SUSPEND) || \
 defined(CONFIG_CPU_IDLE)
+static void do_l2shutdown_settings(void)
+{
+       unsigned int v;
+
+       /* Disable L2$ prefetches */
+       asm volatile(
+       "       mrc     p15, 1, %0, c15, c0, 3\n"
+       "       orr     %0, %0, %1\n"
+       "       mcr     p15, 1, %0, c15, c0, 3\n"
+               : "=&r" (v)
+               : "Ir" (0x400)
+               : "cc");
+       isb();
+       dsb();
+
+       flush_cache_all();
+
+       /* Set Double lock control bit */
+       __asm__ __volatile__("mcr p14, 0, %0, c1, c3, 4" : : "r" (0x1));
+}
+
 static inline void cpu_enter_lowpower_a15(void)
 {
+       if (is_a15_l2shutdown)
+               do_l2shutdown_settings();
+
        v7_exit_coherency_flush(louis);
 }

arch/arm/mach-shmobile/platsmp-apmu.c static int shmobile_smp_apmu_enter_suspend(suspend_state_t state) · line 272

Quoted 4 lines
arch/arm/mach-shmobile/platsmp-apmu.c +1 -0
@@ -245,6 +269,7 @@ static int shmobile_smp_apmu_enter_suspend(suspend_state_t state)
 
        writel_relaxed(0x0, cpucmcr);
        rcar_sysc_clear_event_status();
+       is_a15_l2shutdown = 0;

What's the purpose of clearing is_a15_l2shutdown here?

arch/arm/mach-shmobile/platsmp-apmu.c static int shmobile_smp_apmu_enter_suspend(suspend_state_t state) · line 275

Quoted 3 lines
arch/arm/mach-shmobile/platsmp-apmu.c +0 -0
        return 0;
 }

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]

In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

author
#2 lore raw
In reply to Khiem Nguyen

Hi Geert-san,

Quoted 51 lines · Geert Uytterhoeven

Hi Khiem-san,

Quoted 47 lines · Khiem Nguyen

According to Cortex-A15 TRM, some additional settings are needed. Although the procedure was not completely same as in TRM, it was referred to vexpress implementation to arrange order of additional settings.

Signed-off-by Khiem Nguyen <[email protected]>
---
 arch/arm/mach-shmobile/platsmp-apmu.c |   25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
arch/arm/mach-shmobile/platsmp-apmu.c +24 -0
index dfa8a18..0dedb13 100644
@@ -161,8 +161,32 @@ int shmobile_smp_apmu_boot_secondary(unsigned int cpu, struct task_struct *idle)
 
 #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_SUSPEND) || \
 defined(CONFIG_CPU_IDLE)
+static void do_l2shutdown_settings(void)
+{
+       unsigned int v;
+
+       /* Disable L2$ prefetches */
+       asm volatile(
+       "       mrc     p15, 1, %0, c15, c0, 3\n"
+       "       orr     %0, %0, %1\n"
+       "       mcr     p15, 1, %0, c15, c0, 3\n"
+               : "=&r" (v)
+               : "Ir" (0x400)
+               : "cc");
+       isb();
+       dsb();
+
+       flush_cache_all();
+
+       /* Set Double lock control bit */
+       __asm__ __volatile__("mcr p14, 0, %0, c1, c3, 4" : : "r" (0x1));
+}
+
 static inline void cpu_enter_lowpower_a15(void)
 {
+       if (is_a15_l2shutdown)
+               do_l2shutdown_settings();
+
        v7_exit_coherency_flush(louis);
 }
Quoted 7 lines

arch/arm/mach-shmobile/platsmp-apmu.c static int shmobile_smp_apmu_enter_suspend(suspend_state_t state) · line 272

Quoted 5 lines
arch/arm/mach-shmobile/platsmp-apmu.c +1 -0
@@ -245,6 +269,7 @@ static int shmobile_smp_apmu_enter_suspend(suspend_state_t state)
 
        writel_relaxed(0x0, cpucmcr);
        rcar_sysc_clear_event_status();
+       is_a15_l2shutdown = 0;

What's the purpose of clearing is_a15_l2shutdown here?

As this bit was set in suspend processing,
it should be cleared in resume processing.
And this is to make sure L2shutdown setting is only executed within Suspend-to-RAM, not CPUIdle/Core-Standby or CPU hotplug. :)

Quoted 15 lines

arch/arm/mach-shmobile/platsmp-apmu.c static int shmobile_smp_apmu_enter_suspend(suspend_state_t state) · line 275

Quoted 3 lines
arch/arm/mach-shmobile/platsmp-apmu.c +0 -0
        return 0;
 }

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]

In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

Signature · 2 lines
Best regards,
KHIEM Nguyen