ARM: exynos: Fix undefined instruction during Exynos5422 resume

During early system resume on Exynos5422 with performance counters enabled
the following kernel oops happens:

Internal error: Oops - undefined instruction: 0 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 1433 Comm: bash Tainted: G        W         5.0.0-rc5-next-20190208-00023-gd5fb5a8a13e6-dirty #5480
Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
PC is at reset_ctrl_regs+0x128/0x354
LR is at reset_ctrl_regs+0x124/0x354
pc : [<c0112814>]    lr : [<c0112810>]    psr: 600001d3
...
Flags: nZCv  IRQs off  FIQs off  Mode SVC_32  ISA ARM  Segment none
Control: 10c5387d  Table: 4451006a  DAC: 00000051
Process bash (pid: 1433, stack limit = 0xb7e0e22f)
...
[<c0112814>] (reset_ctrl_regs) from [<c0112ad0>] (dbg_cpu_pm_notify+0x1c/0x24)
[<c0112ad0>] (dbg_cpu_pm_notify) from [<c014c840>] (notifier_call_chain+0x44/0x84)
[<c014c840>] (notifier_call_chain) from [<c014cbc0>] (__atomic_notifier_call_chain+0x7c/0x128)
[<c014cbc0>] (__atomic_notifier_call_chain) from [<c01ffaac>] (cpu_pm_notify+0x30/0x54)
[<c01ffaac>] (cpu_pm_notify) from [<c055116c>] (syscore_resume+0x98/0x3f4)
[<c055116c>] (syscore_resume) from [<c0189350>] (suspend_devices_and_enter+0x97c/0xe74)
[<c0189350>] (suspend_devices_and_enter) from [<c0189fb8>] (pm_suspend+0x770/0xc04)
[<c0189fb8>] (pm_suspend) from [<c0187740>] (state_store+0x6c/0xcc)
[<c0187740>] (state_store) from [<c09fa698>] (kobj_attr_store+0x14/0x20)
[<c09fa698>] (kobj_attr_store) from [<c030159c>] (sysfs_kf_write+0x4c/0x50)
[<c030159c>] (sysfs_kf_write) from [<c0300620>] (kernfs_fop_write+0xfc/0x1e0)
[<c0300620>] (kernfs_fop_write) from [<c0282be8>] (__vfs_write+0x2c/0x160)
[<c0282be8>] (__vfs_write) from [<c0282ea4>] (vfs_write+0xa4/0x16c)
[<c0282ea4>] (vfs_write) from [<c0283080>] (ksys_write+0x40/0x8c)
[<c0283080>] (ksys_write) from [<c0101000>] (ret_fast_syscall+0x0/0x28)
...
---[ end trace 03fc9866185939bf ]---

Undefined instruction is triggered during CP14 reset, because bits: #16
(Secure privileged invasive debug disabled) and #17 (Secure privileged
noninvasive debug disable) are set in DSCR. Those bits depend on SPNIDEN
and SPIDEN lines, which are provided by Secure JTAG hardware block. That
block in turn is powered from cluster 0 (big/Eagle), but the Exynos5422
boots on cluster 1 (LITTLE/KFC).

To fix this issue it is enough to turn on the power on the cluster 0 for
a while. This lets the Secure JTAG block to propagate the needed signals
to LITTLE/KFC cores and change their DSCR.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Change-Id: I0fa6618740853169bd96efeb33975f0289ac3706

diff --git a/arch/arm/mach-exynos/suspend.c b/arch/arm/mach-exynos/suspend.c
index fcc8390..49bb921 100644 (file)
--- a/arch/arm/mach-exynos/suspend.c
+++ b/arch/arm/mach-exynos/suspend.c
@@ -453,8 +453,27 @@ early_wakeup:
 
 static void exynos5420_prepare_pm_resume(void)
 {
+       unsigned int mpidr, cluster;
+
+       mpidr = read_cpuid_mpidr();
+       cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
+
        if (IS_ENABLED(CONFIG_EXYNOS5420_MCPM))
                WARN_ON(mcpm_cpu_powered_up());
+
+       if (IS_ENABLED(CONFIG_HW_PERF_EVENTS) && cluster != 0) {
+               /*
+                * When system is resumed on the LITTLE/KFC core (cluster 1),
+                * the DSCR is not properly updated until the power is turned
+                * on also for the cluster 0. Enable it for a while to
+                * propagate the SPNIDEN and SPIDEN signals from Secure JTAG
+                * block and avoid undefined instruction issue on CP14 reset.
+                */
+               pmu_raw_writel(S5P_CORE_LOCAL_PWR_EN,
+                               EXYNOS_COMMON_CONFIGURATION(0));
+               pmu_raw_writel(0,
+                               EXYNOS_COMMON_CONFIGURATION(0));
+       }
 }
 
 static void exynos5420_pm_resume(void)