[PATCH v6 7/7] ARM: tegra: Add firmware calls required for suspend-resume on Tegra30

Dmitry Osipenko
2019-02-22T19:36:18Z

In order to suspend-resume CPU with Trusted Foundations firmware being
present on Tegra30, the LP1/LP2 boot vectors and CPU caches need to be
set up using the firmware calls and then suspend code shall avoid
re-disabling parts that were disabled by the firmware.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
arch/arm/mach-tegra/pm.c | 49 +++++++++++++++++++++++++++++
arch/arm/mach-tegra/reset-handler.S | 26 +++++++++++++++
arch/arm/mach-tegra/sleep.S | 14 ++++++---
3 files changed, 84 insertions(+), 5 deletions(-)

diff --git a/arch/arm/mach-tegra/pm.c b/arch/arm/mach-tegra/pm.c
index 1ad5719779b0..f209f59e0daf 100644
--- a/arch/arm/mach-tegra/pm.c
+++ b/arch/arm/mach-tegra/pm.c
@@ -33,11 +33,13 @@
#include <soc/tegra/pmc.h>

#include <asm/cacheflush.h>
+#include <asm/firmware.h>
#include <asm/idmap.h>
#include <asm/proc-fns.h>
#include <asm/smp_plat.h>
#include <asm/suspend.h>
#include <asm/tlbflush.h>
+#include <asm/trusted_foundations.h>

#include "iomap.h"
#include "pm.h"
@@ -159,6 +161,28 @@ int tegra_cpu_do_idle(void)

static int tegra_sleep_cpu(unsigned long v2p)
{
+ /*
+ * L2 cache disabling using kernel API only allowed when all
+ * secondary CPU's are offline. Cache have to be disabled with
+ * MMU-on 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-idle
+ * code-path only for Tegra20/30.
+ */
+ if (trusted_foundations_registered())
+ outer_disable();
+
+ /*
+ * Note that besides of setting up CPU reset vector this firmware
+ * call may also do the following, depending on the FW version:
+ * 1) Disable L2. But this doesn't matter since we already
+ * disabled the L2.
+ * 2) Disable D-cache. This need to be taken into account in
+ * particular by the tegra_disable_clean_inv_dcache() which
+ * shall avoid the re-disable.
+ */
+ call_firmware_op(prepare_idle, TF_PM_MODE_LP2);
+
setup_mm_for_reboot();
tegra_sleep_cpu_finish(v2p);

@@ -197,6 +221,14 @@ void tegra_idle_lp2_last(void)

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. This is always a no-op on Tegra114+.
+ */
+ outer_resume();
+
restore_cpu_complex();
cpu_cluster_pm_exit();
}
@@ -215,6 +247,15 @@ enum tegra_suspend_mode tegra_pm_validate_suspend_mode(

static int tegra_sleep_core(unsigned long v2p)
{
+ /*
+ * Cache have to be disabled with MMU-on if cache maintenance is done
+ * via Trusted Foundations firmware. This is a no-op on Tegra114+.
+ */
+ if (trusted_foundations_registered())
+ outer_disable();
+
+ call_firmware_op(prepare_idle, TF_PM_MODE_LP1);
+
setup_mm_for_reboot();
tegra_sleep_core_finish(v2p);

@@ -342,6 +383,14 @@ static int tegra_suspend_enter(suspend_state_t state)

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 3bf202819534..19a609046547 100644
--- a/arch/arm/mach-tegra/reset-handler.S
+++ b/arch/arm/mach-tegra/reset-handler.S
@@ -20,6 +20,7 @@
#include <soc/tegra/flowctrl.h>
#include <soc/tegra/fuse.h>

+#include <asm/assembler.h>
#include <asm/asm-offsets.h>
#include <asm/cache.h>

@@ -76,6 +77,7 @@ ENTRY(tegra_resume)
orr r1, r1, #1
str r1, [r0]
#endif
+ bl tegra_resume_trusted_foundations

#ifdef CONFIG_CACHE_L2X0
/* L2 cache resume & re-enable */
@@ -88,6 +90,30 @@ end_ca9_scu_l2_resume:

b cpu_resume
ENDPROC(tegra_resume)
+
+/*
+ * tegra_resume_trusted_foundations
+ *
+ * Trusted Foundations firmware initialization.
+ *
+ * Doesn't return if firmware presents.
+ * Corrupted registers: r1, r2
+ */
+ENTRY(tegra_resume_trusted_foundations)
+ /* Check whether Trusted Foundations firmware presents. */
+ mov32 r2, TEGRA_IRAM_BASE + TEGRA_IRAM_RESET_HANDLER_OFFSET
+ ldr r1, =__tegra_cpu_reset_handler_data_offset + \
+ RESET_DATA(TF_PRESENT)
+ ldr r1, [r2, r1]
+ cmp r1, #0
+ reteq lr
+
+ .arch_extension sec
+ /* First call after suspend wakes firmware. No arguments required. */
+ smc #0
+
+ b cpu_resume
+ENDPROC(tegra_resume_trusted_foundations)
#endif

.align L1_CACHE_SHIFT
diff --git a/arch/arm/mach-tegra/sleep.S b/arch/arm/mach-tegra/sleep.S
index 5e3496753df1..53863d59521b 100644
--- a/arch/arm/mach-tegra/sleep.S
+++ b/arch/arm/mach-tegra/sleep.S
@@ -49,8 +49,9 @@ ENTRY(tegra_disable_clean_inv_dcache)

/* Disable the D-cache */
mrc p15, 0, r2, c1, c0, 0
+ tst r2, #CR_C @ see tegra_sleep_cpu()
bic r2, r2, #CR_C
- mcr p15, 0, r2, c1, c0, 0
+ mcrne p15, 0, r2, c1, c0, 0
isb

/* Flush the D-cache */
@@ -132,10 +133,13 @@ ENTRY(tegra_shut_off_mmu)
#ifdef CONFIG_CACHE_L2X0
/* Disable L2 cache */
check_cpu_part_num 0xc09, r9, r10
- movweq r2, #:lower16:(TEGRA_ARM_PERIF_BASE + 0x3000)
- movteq r2, #:upper16:(TEGRA_ARM_PERIF_BASE + 0x3000)
- moveq r3, #0
- streq r3, [r2, #L2X0_CTRL]
+ retne r0
+
+ mov32 r2, TEGRA_ARM_PERIF_BASE + 0x3000
+ ldr r3, [r2, #L2X0_CTRL]
+ mov r9, #0
+ tst r3, #1 @ see tegra_sleep_cpu()
+ strne r9, [r2, #L2X0_CTRL]
#endif
ret r0
ENDPROC(tegra_shut_off_mmu)
--
2.20.1