From: Mirela Simonovic <mirela.simonovic@aggios.com>

Invoke PSCI SYSTEM_SUSPEND to finalize Xen's suspend sequence on ARM64 platforms.
Pass the resume entry point (hyp_resume) as the first argument to EL3. The resume
handler is currently a stub and will be implemented later in assembly. Ignore the
context ID argument, as is done in Linux.

Only enable this path when CONFIG_SYSTEM_SUSPEND is set and
PSCI version is >= 1.0.

Signed-off-by: Mirela Simonovic <mirela.simonovic@aggios.com>
Signed-off-by: Saeed Nowshadi <saeed.nowshadi@xilinx.com>
Signed-off-by: Mykyta Poturai <mykyta_poturai@epam.com>
Signed-off-by: Mykola Kvach <mykola_kvach@epam.com>
---
Changes in v6:
- move calling of call_psci_system_suspend to commit that
  implements system_suspend call

Changes in v4:
  - select the appropriate PSCI SYSTEM_SUSPEND function ID based on platform
  - update comments and commit message to reflect recent changes

Changes in v3:
  - return PSCI_NOT_SUPPORTED instead of a hardcoded 1 on ARM32
  - check PSCI version before invoking SYSTEM_SUSPEND in call_psci_system_suspend
---
 xen/arch/arm/arm64/head.S          |  8 ++++++++
 xen/arch/arm/include/asm/psci.h    |  1 +
 xen/arch/arm/include/asm/suspend.h | 22 ++++++++++++++++++++++
 xen/arch/arm/psci.c                | 23 ++++++++++++++++++++++-
 4 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 xen/arch/arm/include/asm/suspend.h

diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S
index 72c7b24498..3522c497c5 100644
--- a/xen/arch/arm/arm64/head.S
+++ b/xen/arch/arm/arm64/head.S
@@ -561,6 +561,14 @@ END(efi_xen_start)
 
 #endif /* CONFIG_ARM_EFI */
 
+#ifdef CONFIG_SYSTEM_SUSPEND
+
+FUNC(hyp_resume)
+        b .
+END(hyp_resume)
+
+#endif /* CONFIG_SYSTEM_SUSPEND */
+
 /*
  * Local variables:
  * mode: ASM
diff --git a/xen/arch/arm/include/asm/psci.h b/xen/arch/arm/include/asm/psci.h
index 48a93e6b79..bb3c73496e 100644
--- a/xen/arch/arm/include/asm/psci.h
+++ b/xen/arch/arm/include/asm/psci.h
@@ -23,6 +23,7 @@ int call_psci_cpu_on(int cpu);
 void call_psci_cpu_off(void);
 void call_psci_system_off(void);
 void call_psci_system_reset(void);
+int call_psci_system_suspend(void);
 
 /* Range of allocated PSCI function numbers */
 #define	PSCI_FNUM_MIN_VALUE                 _AC(0,U)
diff --git a/xen/arch/arm/include/asm/suspend.h b/xen/arch/arm/include/asm/suspend.h
new file mode 100644
index 0000000000..7e04c6e915
--- /dev/null
+++ b/xen/arch/arm/include/asm/suspend.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __ASM_ARM_SUSPEND_H__
+#define __ASM_ARM_SUSPEND_H__
+
+#ifdef CONFIG_SYSTEM_SUSPEND
+
+void hyp_resume(void);
+
+#endif /* CONFIG_SYSTEM_SUSPEND */
+
+#endif /* __ASM_ARM_SUSPEND_H__ */
+
+ /*
+  * Local variables:
+  * mode: C
+  * c-file-style: "BSD"
+  * c-basic-offset: 4
+  * tab-width: 4
+  * indent-tabs-mode: nil
+  * End:
+  */
diff --git a/xen/arch/arm/psci.c b/xen/arch/arm/psci.c
index b6860a7760..c9d126b195 100644
--- a/xen/arch/arm/psci.c
+++ b/xen/arch/arm/psci.c
@@ -17,17 +17,20 @@
 #include <asm/cpufeature.h>
 #include <asm/psci.h>
 #include <asm/acpi.h>
+#include <asm/suspend.h>
 
 /*
  * While a 64-bit OS can make calls with SMC32 calling conventions, for
  * some calls it is necessary to use SMC64 to pass or return 64-bit values.
- * For such calls PSCI_0_2_FN_NATIVE(x) will choose the appropriate
+ * For such calls PSCI_*_FN_NATIVE(x) will choose the appropriate
  * (native-width) function ID.
  */
 #ifdef CONFIG_ARM_64
 #define PSCI_0_2_FN_NATIVE(name)    PSCI_0_2_FN64_##name
+#define PSCI_1_0_FN_NATIVE(name)    PSCI_1_0_FN64_##name
 #else
 #define PSCI_0_2_FN_NATIVE(name)    PSCI_0_2_FN32_##name
+#define PSCI_1_0_FN_NATIVE(name)    PSCI_1_0_FN32_##name
 #endif
 
 uint32_t psci_ver;
@@ -60,6 +63,24 @@ void call_psci_cpu_off(void)
     }
 }
 
+int call_psci_system_suspend(void)
+{
+#ifdef CONFIG_SYSTEM_SUSPEND
+    struct arm_smccc_res res;
+
+    if ( psci_ver < PSCI_VERSION(1, 0) )
+        return PSCI_NOT_SUPPORTED;
+
+    /* 2nd argument (context ID) is not used */
+    arm_smccc_smc(PSCI_1_0_FN_NATIVE(SYSTEM_SUSPEND), __pa(hyp_resume), &res);
+    return PSCI_RET(res);
+#else
+    dprintk(XENLOG_WARNING,
+            "SYSTEM_SUSPEND not supported (CONFIG_SYSTEM_SUSPEND disabled)\n");
+    return PSCI_NOT_SUPPORTED;
+#endif
+}
+
 void call_psci_system_off(void)
 {
     if ( psci_ver > PSCI_VERSION(0, 1) )
-- 
2.48.1