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Subject[PATCH v2 2/2] ARM: at91: pm: add support for sama5d2 secure suspend
Date
When running with OP-TEE, the suspend control is handled securely.
Suspend can be entered using PSCI support. Since the sama5d2 supports
multiple suspend modes, add a new CONFIG_ATMEL_SECURE_PM which will
send a SMC call to select the suspend mode at init time.

"atmel.pm_modes" boot argument is still supported for compatibility
purposes but the standby value is actually ignored since PSCI suspend
is used and it only support one mode (suspend).

Signed-off-by: Clément Léger <clement.leger@bootlin.com>
---
arch/arm/mach-at91/Kconfig | 12 ++++++++++-
arch/arm/mach-at91/pm.c | 38 +++++++++++++++++++++++++++++++++
arch/arm/mach-at91/sam_secure.h | 4 ++++
3 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-at91/Kconfig b/arch/arm/mach-at91/Kconfig
index 02f6b108fd5d..5a6ca38d6303 100644
--- a/arch/arm/mach-at91/Kconfig
+++ b/arch/arm/mach-at91/Kconfig
@@ -208,7 +208,17 @@ config SOC_SAMA5
select SRAM if PM

config ATMEL_PM
- bool
+ bool "Atmel PM support"
+
+config ATMEL_SECURE_PM
+ bool "Atmel Secure PM support"
+ depends on SOC_SAMA5D2 && ATMEL_PM
+ select ARM_PSCI
+ help
+ When running under a TEE, the suspend mode must be requested to be set
+ at TEE level. When enable, this option will use secure monitor calls
+ to set the suspend level. PSCI is then used to enter suspend.
+ NOTE: This support is mutually exclusive with CONFIG_ATMEL_PM

config SOC_SAMA7
bool
diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c
index dd6f4ce3f766..e40515691540 100644
--- a/arch/arm/mach-at91/pm.c
+++ b/arch/arm/mach-at91/pm.c
@@ -27,6 +27,7 @@

#include "generic.h"
#include "pm.h"
+#include "sam_secure.h"

#define BACKUP_DDR_PHY_CALIBRATION (9)

@@ -856,6 +857,35 @@ static int __init at91_pm_backup_init(void)
return ret;
}

+static void at91_pm_secure_init(void)
+{
+ int suspend_mode;
+ struct arm_smccc_res res;
+
+ suspend_mode = soc_pm.data.suspend_mode;
+
+ res = sam_smccc_call(SAMA5_SMC_SIP_SET_SUSPEND_MODE,
+ suspend_mode, 0);
+ if (res.a0 == 0) {
+ pr_info("AT91: Secure PM: suspend mode set to %s\n",
+ pm_modes[suspend_mode].pattern);
+ return;
+ }
+
+ pr_warn("AT91: Secure PM: %s mode not supported !\n",
+ pm_modes[suspend_mode].pattern);
+
+ res = sam_smccc_call(SAMA5_SMC_SIP_GET_SUSPEND_MODE, 0, 0);
+ if (res.a0 == 0) {
+ pr_warn("AT91: Secure PM: failed to get default mode\n");
+ return;
+ }
+
+ pr_info("AT91: Secure PM: using default suspend mode %s\n",
+ pm_modes[suspend_mode].pattern);
+
+ soc_pm.data.suspend_mode = res.a1;
+}
static const struct of_device_id atmel_shdwc_ids[] = {
{ .compatible = "atmel,sama5d2-shdwc" },
{ .compatible = "microchip,sam9x60-shdwc" },
@@ -1188,6 +1218,11 @@ void __init sama5d2_pm_init(void)
if (!IS_ENABLED(CONFIG_SOC_SAMA5D2))
return;

+ if (IS_ENABLED(CONFIG_ATMEL_SECURE_PM)) {
+ at91_pm_secure_init();
+ return;
+ }
+
at91_pm_modes_validate(modes, ARRAY_SIZE(modes));
at91_pm_modes_init(iomaps, ARRAY_SIZE(iomaps));
ret = at91_dt_ramc(false);
@@ -1262,6 +1297,9 @@ static int __init at91_pm_modes_select(char *str)
soc_pm.data.standby_mode = standby;
soc_pm.data.suspend_mode = suspend;

+ if (IS_ENABLED(CONFIG_ATMEL_SECURE_PM))
+ pr_warn("AT91: Secure PM: ignoring standby mode\n");
+
return 0;
}
early_param("atmel.pm_modes", at91_pm_modes_select);
diff --git a/arch/arm/mach-at91/sam_secure.h b/arch/arm/mach-at91/sam_secure.h
index 360036672f52..1e7d8b20ba1e 100644
--- a/arch/arm/mach-at91/sam_secure.h
+++ b/arch/arm/mach-at91/sam_secure.h
@@ -8,6 +8,10 @@

#include <linux/arm-smccc.h>

+/* Secure Monitor mode APIs */
+#define SAMA5_SMC_SIP_SET_SUSPEND_MODE 0x400
+#define SAMA5_SMC_SIP_GET_SUSPEND_MODE 0x401
+
void __init sam_secure_init(void);
struct arm_smccc_res sam_smccc_call(u32 fn, u32 arg0, u32 arg1);

--
2.34.1
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