[PATCH v3 7/8] ARM: tegra: Support L2 cache maintenance done via firmware

Dmitry Osipenko
2018-08-30T18:05:33Z

Trusted Foundations firmware require MMU to be enabled for L2 cache
maintenance on Tegra30, hence perform the maintenance early-late on
suspend-resume respectively.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
arch/arm/mach-tegra/pm.c | 36 +++++++++++++++++++++++++++++
arch/arm/mach-tegra/reset-handler.S | 8 ++-----
arch/arm/mach-tegra/sleep.S | 4 ++++
3 files changed, 42 insertions(+), 6 deletions(-)

diff --git a/arch/arm/mach-tegra/pm.c b/arch/arm/mach-tegra/pm.c
index 1ad5719779b0..66c8cd63dd86 100644
--- a/arch/arm/mach-tegra/pm.c
+++ b/arch/arm/mach-tegra/pm.c
@@ -38,6 +38,7 @@
#include <asm/smp_plat.h>
#include <asm/suspend.h>
#include <asm/tlbflush.h>
+#include <asm/trusted_foundations.h>

#include "iomap.h"
#include "pm.h"
@@ -195,8 +196,27 @@ void tegra_idle_lp2_last(void)
cpu_cluster_pm_enter();
suspend_cpu_complex();

+ /*
+ * L2 cache disabling using kernel API only allowed when all
+ * secondary CPU's are offline. Cache have to be disabled early
+ * if cache maintenance is done via Trusted Foundations firmware.
+ * Note that CPUIDLE won't ever enter powergate on Tegra30 if any
+ * of secondary CPU's is online and this is the LP2 codepath only
+ * for Tegra20/30.
+ */
+ if (trusted_foundations_registered())
+ outer_disable();
+
cpu_suspend(PHYS_OFFSET - PAGE_OFFSET, &tegra_sleep_cpu);

+ /*
+ * Resume L2 cache if it wasn't re-enabled early during resume,
+ * which is the case for Tegra30 that has to re-enable the cache
+ * via firmware call. In other cases cache is already enabled and
+ * hence re-enabling is a no-op.
+ */
+ outer_resume();
+
restore_cpu_complex();
cpu_cluster_pm_exit();
}
@@ -340,8 +360,24 @@ static int tegra_suspend_enter(suspend_state_t state)
break;
}

+ /*
+ * Cache have to be disabled early if cache maintenance is done
+ * via Trusted Foundations firmware. Otherwise this is a no-op,
+ * like on Tegra114+.
+ */
+ if (trusted_foundations_registered())
+ outer_disable();
+
cpu_suspend(PHYS_OFFSET - PAGE_OFFSET, tegra_sleep_func);

+ /*
+ * Resume L2 cache if it wasn't re-enabled early during resume,
+ * which is the case for Tegra30 that has to re-enable the cache
+ * via firmware call. In other cases cache is already enabled and
+ * hence re-enabling is a no-op.
+ */
+ outer_resume();
+
switch (mode) {
case TEGRA_SUSPEND_LP1:
tegra_suspend_exit_lp1();
diff --git a/arch/arm/mach-tegra/reset-handler.S b/arch/arm/mach-tegra/reset-handler.S
index 555c652f5a07..4973ea053bd7 100644
--- a/arch/arm/mach-tegra/reset-handler.S
+++ b/arch/arm/mach-tegra/reset-handler.S
@@ -69,7 +69,7 @@ ENTRY(tegra_resume)

mov32 r9, 0xc09
cmp r8, r9
- bne end_ca9_scu_l2_resume
+ bne end_ca9_scu_resume
#ifdef CONFIG_HAVE_ARM_SCU
/* enable SCU */
mov32 r0, TEGRA_ARM_PERIF_BASE
@@ -78,11 +78,7 @@ ENTRY(tegra_resume)
str r1, [r0]
#endif

-#ifdef CONFIG_CACHE_L2X0
- /* L2 cache resume & re-enable */
- bl l2c310_early_resume
-#endif
-end_ca9_scu_l2_resume:
+end_ca9_scu_resume:
mov32 r9, 0xc0f
cmp r8, r9
bleq tegra_init_l2_for_a15
diff --git a/arch/arm/mach-tegra/sleep.S b/arch/arm/mach-tegra/sleep.S
index 5e3496753df1..b96126fe5dc5 100644
--- a/arch/arm/mach-tegra/sleep.S
+++ b/arch/arm/mach-tegra/sleep.S
@@ -132,8 +132,12 @@ ENTRY(tegra_shut_off_mmu)
#ifdef CONFIG_CACHE_L2X0
/* Disable L2 cache */
check_cpu_part_num 0xc09, r9, r10
+ retne r0
+
movweq r2, #:lower16:(TEGRA_ARM_PERIF_BASE + 0x3000)
movteq r2, #:upper16:(TEGRA_ARM_PERIF_BASE + 0x3000)
+ ldr r3, [r2, #L2X0_CTRL]
+ cmp r3, #1
moveq r3, #0
streq r3, [r2, #L2X0_CTRL]
#endif
--
2.18.0