linux-kernel - [PATCH v4 4/4] ARM: OMAP2+: sleep43xx: Call secure suspend/resume handlers

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Message-ID: <20200102211943.20480-5-afd@ti.com>
Date:   Thu, 2 Jan 2020 16:19:43 -0500
From:   "Andrew F. Davis" <afd@...com>
To:     Tony Lindgren <tony@...mide.com>, Lokesh Vutla <lokeshvutla@...com>
CC:     <linux-omap@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        "Andrew F . Davis" <afd@...com>
Subject: [PATCH v4 4/4] ARM: OMAP2+: sleep43xx: Call secure suspend/resume handlers

During suspend CPU context may be lost in both non-secure and secure CPU
states. The kernel can handle saving and restoring the non-secure context
but must call into the secure side to allow it to save any context it may
lose. Add these calls here.

Note that on systems with OP-TEE available the suspend call is issued to
OP-TEE using the ARM SMCCC, but the resume call is always issued to the
ROM. This is because on waking from suspend the ROM is restored as the
secure monitor. It is this resume call that instructs the ROM to restore
OP-TEE, all subsequent calls will be handled by OP-TEE and should use the
ARM SMCCC.

Signed-off-by: Andrew F. Davis <afd@...com>
Acked-by: Dave Gerlach <d-gerlach@...com>
---
 arch/arm/mach-omap2/omap-secure.h |  3 +++
 arch/arm/mach-omap2/pm33xx-core.c | 24 ++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/arch/arm/mach-omap2/omap-secure.h b/arch/arm/mach-omap2/omap-secure.h
index 736e594365f4..ba8c486c0454 100644
--- a/arch/arm/mach-omap2/omap-secure.h
+++ b/arch/arm/mach-omap2/omap-secure.h
@@ -53,6 +53,9 @@
 #define OMAP4_PPA_L2_POR_INDEX		0x23
 #define OMAP4_PPA_CPU_ACTRL_SMP_INDEX	0x25
 
+#define AM43xx_PPA_SVC_PM_SUSPEND	0x71
+#define AM43xx_PPA_SVC_PM_RESUME	0x72
+
 /* Secure RX-51 PPA (Primary Protected Application) APIs */
 #define RX51_PPA_HWRNG			29
 #define RX51_PPA_L2_INVAL		40
diff --git a/arch/arm/mach-omap2/pm33xx-core.c b/arch/arm/mach-omap2/pm33xx-core.c
index f11442ed3eff..7461b0346549 100644
--- a/arch/arm/mach-omap2/pm33xx-core.c
+++ b/arch/arm/mach-omap2/pm33xx-core.c
@@ -28,6 +28,7 @@
 #include "prm33xx.h"
 #include "soc.h"
 #include "sram.h"
+#include "omap-secure.h"
 
 static struct powerdomain *cefuse_pwrdm, *gfx_pwrdm, *per_pwrdm, *mpu_pwrdm;
 static struct clockdomain *gfx_l4ls_clkdm;
@@ -166,6 +167,16 @@ static int am43xx_suspend(unsigned int state, int (*fn)(unsigned long),
 {
 	int ret = 0;
 
+	/* Suspend secure side on HS devices */
+	if (omap_type() != OMAP2_DEVICE_TYPE_GP) {
+		if (optee_available)
+			omap_smccc_smc(AM43xx_PPA_SVC_PM_SUSPEND, 0);
+		else
+			omap_secure_dispatcher(AM43xx_PPA_SVC_PM_SUSPEND,
+					       FLAG_START_CRITICAL,
+					       0, 0, 0, 0, 0);
+	}
+
 	amx3_pre_suspend_common();
 	scu_power_mode(scu_base, SCU_PM_POWEROFF);
 	ret = cpu_suspend(args, fn);
@@ -174,6 +185,19 @@ static int am43xx_suspend(unsigned int state, int (*fn)(unsigned long),
 	if (!am43xx_check_off_mode_enable())
 		amx3_post_suspend_common();
 
+	/*
+	 * Resume secure side on HS devices.
+	 *
+	 * Note that even on systems with OP-TEE available this resume call is
+	 * issued to the ROM. This is because upon waking from suspend the ROM
+	 * is restored as the secure monitor. On systems with OP-TEE ROM will
+	 * restore OP-TEE during this call.
+	 */
+	if (omap_type() != OMAP2_DEVICE_TYPE_GP)
+		omap_secure_dispatcher(AM43xx_PPA_SVC_PM_RESUME,
+				       FLAG_START_CRITICAL,
+				       0, 0, 0, 0, 0);
+
 	return ret;
 }
 
-- 
2.17.1