[Xen-devel] [PATCH 08/18] xen/arm: Disable/enable non-boot physical CPUs on suspend/resume

[Mirela Simonovic <mirela.simonovic@xxxxxxxxxx>]

Non-boot CPUs have to be disabled on suspend and enabled on resume
(hotplug-based mechanism). Disabling non-boot CPUs will lead to PSCI
CPU_OFF to be called by each non-boot CPU. Depending on the underlying
platform capabilities, this may lead to the physical powering down of
CPUs. Tested on Xilinx Zynq Ultrascale+ MPSoC (including power down of
each non-boot CPU).

Signed-off-by: Mirela Simonovic <mirela.simonovic@xxxxxxxxxx>
Signed-off-by: Saeed Nowshadi <saeed.nowshadi@xxxxxxxxxx>
---
 xen/arch/arm/suspend.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/suspend.c b/xen/arch/arm/suspend.c
index 575afd5eb8..dae1b1f7d6 100644
--- a/xen/arch/arm/suspend.c
+++ b/xen/arch/arm/suspend.c
@@ -1,4 +1,5 @@
 #include <xen/sched.h>
+#include <xen/cpu.h>
 #include <asm/cpufeature.h>
 #include <asm/event.h>
 #include <asm/psci.h>
@@ -115,17 +116,29 @@ static void vcpu_suspend(register_t epoint, register_t 
cid)
 /* Xen suspend. Note: data is not used (suspend is the suspend to RAM) */
 static long system_suspend(void *data)
 {
+    int status;
+
     BUG_ON(system_state != SYS_STATE_active);
 
     system_state = SYS_STATE_suspend;
     freeze_domains();
 
+    status = disable_nonboot_cpus();
+    if ( status )
+    {
+        system_state = SYS_STATE_resume;
+        goto resume_nonboot_cpus;
+    }
+
     system_state = SYS_STATE_resume;
 
+resume_nonboot_cpus:
+    enable_nonboot_cpus();
     thaw_domains();
     system_state = SYS_STATE_active;
+    dsb(sy);
 
-    return -ENOSYS;
+    return status;
 }
 
 int32_t domain_suspend(register_t epoint, register_t cid)
-- 
2.13.0


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