[PATCH v4][PART 2 08/10] xen/arm: Implement PSCI SYSTEM_SUSPEND call (host interface)

[Mykola Kvach <xakep.amatop@xxxxxxxxx>]

From: Mirela Simonovic <mirela.simonovic@xxxxxxxxxx>

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@xxxxxxxxxx>
Signed-off-by: Saeed Nowshadi <saeed.nowshadi@xxxxxxxxxx>
Signed-off-by: Mykyta Poturai <mykyta_poturai@xxxxxxxx>
Signed-off-by: Mykola Kvach <mykola_kvach@xxxxxxxx>
---
Changes in v4:
  - select the appropriate PSCI SYSTEM_SUSPEND function ID based on arch
  - 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 |  2 ++
 xen/arch/arm/psci.c                | 23 ++++++++++++++++++++++-
 xen/arch/arm/suspend.c             |  5 +++++
 5 files changed, 38 insertions(+), 1 deletion(-)

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
index 78d0e2383b..55041a5d06 100644
--- a/xen/arch/arm/include/asm/suspend.h
+++ b/xen/arch/arm/include/asm/suspend.h
@@ -7,6 +7,8 @@
 
 int host_system_suspend(void);
 
+void hyp_resume(void);
+
 #endif /* CONFIG_SYSTEM_SUSPEND */
 
 #endif /* __ASM_ARM_SUSPEND_H__ */
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) )
diff --git a/xen/arch/arm/suspend.c b/xen/arch/arm/suspend.c
index 13e59015c0..e3a9b68622 100644
--- a/xen/arch/arm/suspend.c
+++ b/xen/arch/arm/suspend.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#include <asm/psci.h>
 #include <xen/console.h>
 #include <xen/cpu.h>
 #include <xen/sched.h>
@@ -70,6 +71,10 @@ static long system_suspend(void *data)
      */
     update_boot_mapping(true);
 
+    status = call_psci_system_suspend();
+    if ( status )
+        dprintk(XENLOG_WARNING, "PSCI system suspend failed, err=%d\n", 
status);
+
     system_state = SYS_STATE_resume;
     update_boot_mapping(false);
 
-- 
2.48.1