From: James Hogan <james.hogan@xxxxxxxxxx>
Implement a CPU power management callback for restoring trap related CPU
configuration after CPU power up from a low power state. The following
state is restored:
- Status register
- HWREna register
- Exception vector configuration registers
- Context/XContext register
Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx>
Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
---
Changes in v2:
- Fix the non-CONFIG_MIPS_PGD_C0_CONTEXT case which I broke with a
dodgy rebase of this patch (sorry James!).
---
arch/mips/include/asm/mmu_context.h | 15 ++++--
arch/mips/kernel/traps.c | 93 ++++++++++++++++++++++++++++---------
2 files changed, 81 insertions(+), 27 deletions(-)
diff --git a/arch/mips/include/asm/mmu_context.h b/arch/mips/include/asm/mmu_context.h
index e277bba..ecae1dc 100644
--- a/arch/mips/include/asm/mmu_context.h
+++ b/arch/mips/include/asm/mmu_context.h
@@ -31,11 +31,15 @@ do { \
} while (0)
#ifdef CONFIG_MIPS_PGD_C0_CONTEXT
+
+#define TLBMISS_HANDLER_RESTORE() \
+ write_c0_xcontext((unsigned long) smp_processor_id() << \
+ SMP_CPUID_REGSHIFT)
+
#define TLBMISS_HANDLER_SETUP() \
do { \
TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir); \
- write_c0_xcontext((unsigned long) smp_processor_id() << \
- SMP_CPUID_REGSHIFT); \
+ TLBMISS_HANDLER_RESTORE(); \
} while (0)
#else /* !CONFIG_MIPS_PGD_C0_CONTEXT: using pgd_current*/
@@ -47,9 +51,12 @@ do { \
*/
extern unsigned long pgd_current[];
-#define TLBMISS_HANDLER_SETUP() \
+#define TLBMISS_HANDLER_RESTORE() \
write_c0_context((unsigned long) smp_processor_id() << \
- SMP_CPUID_REGSHIFT); \
+ SMP_CPUID_REGSHIFT)
+
+#define TLBMISS_HANDLER_SETUP() \
+ TLBMISS_HANDLER_RESTORE(); \
back_to_back_c0_hazard(); \
TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir)
#endif /* CONFIG_MIPS_PGD_C0_CONTEXT*/
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 074e857..9651f68 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -15,6 +15,7 @@
#include <linux/bug.h>
#include <linux/compiler.h>
#include <linux/context_tracking.h>
+#include <linux/cpu_pm.h>
#include <linux/kexec.h>
#include <linux/init.h>
#include <linux/kernel.h>
@@ -1865,32 +1866,16 @@ static int __init ulri_disable(char *s)
}
__setup("noulri", ulri_disable);
-void per_cpu_trap_init(bool is_boot_cpu)
+/* configure STATUS register */
+static void configure_status(void)
{
- unsigned int cpu = smp_processor_id();
- unsigned int status_set = ST0_CU0;
- unsigned int hwrena = cpu_hwrena_impl_bits;
-#ifdef CONFIG_MIPS_MT_SMTC
- int secondaryTC = 0;
- int bootTC = (cpu == 0);
-
- /*
- * Only do per_cpu_trap_init() for first TC of Each VPE.
- * Note that this hack assumes that the SMTC init code
- * assigns TCs consecutively and in ascending order.
- */
-
- if (((read_c0_tcbind() & TCBIND_CURTC) != 0) &&
- ((read_c0_tcbind() & TCBIND_CURVPE) == cpu_data[cpu - 1].vpe_id))
- secondaryTC = 1;
-#endif /* CONFIG_MIPS_MT_SMTC */
-
/*
* Disable coprocessors and select 32-bit or 64-bit addressing
* and the 16/32 or 32/32 FPR register model. Reset the BEV
* flag that some firmware may have left set and the TS bit (for
* IP27). Set XX for ISA IV code to work.
*/
+ unsigned int status_set = ST0_CU0;
#ifdef CONFIG_64BIT
status_set |= ST0_FR|ST0_KX|ST0_SX|ST0_UX;
#endif
@@ -1901,6 +1886,12 @@ void per_cpu_trap_init(bool is_boot_cpu)
change_c0_status(ST0_CU|ST0_MX|ST0_RE|ST0_FR|ST0_BEV|ST0_TS|ST0_KX|ST0_SX|ST0_UX,
status_set);
+}
+
+/* configure HWRENA register */
+static void configure_hwrena(void)
+{
+ unsigned int hwrena = cpu_hwrena_impl_bits;
if (cpu_has_mips_r2)
hwrena |= 0x0000000f;
@@ -1910,11 +1901,10 @@ void per_cpu_trap_init(bool is_boot_cpu)
if (hwrena)
write_c0_hwrena(hwrena);
+}
-#ifdef CONFIG_MIPS_MT_SMTC
- if (!secondaryTC) {
-#endif /* CONFIG_MIPS_MT_SMTC */
-
+static void configure_exception_vector(void)
+{
if (cpu_has_veic || cpu_has_vint) {
unsigned long sr = set_c0_status(ST0_BEV);
write_c0_ebase(ebase);
@@ -1930,6 +1920,34 @@ void per_cpu_trap_init(bool is_boot_cpu)
} else
set_c0_cause(CAUSEF_IV);
}
+}
+
+void per_cpu_trap_init(bool is_boot_cpu)
+{
+ unsigned int cpu = smp_processor_id();
+#ifdef CONFIG_MIPS_MT_SMTC
+ int secondaryTC = 0;
+ int bootTC = (cpu == 0);
+
+ /*
+ * Only do per_cpu_trap_init() for first TC of Each VPE.
+ * Note that this hack assumes that the SMTC init code
+ * assigns TCs consecutively and in ascending order.
+ */
+
+ if (((read_c0_tcbind() & TCBIND_CURTC) != 0) &&
+ ((read_c0_tcbind() & TCBIND_CURVPE) == cpu_data[cpu - 1].vpe_id))
+ secondaryTC = 1;
+#endif /* CONFIG_MIPS_MT_SMTC */
+
+ configure_status();
+ configure_hwrena();
+
+#ifdef CONFIG_MIPS_MT_SMTC
+ if (!secondaryTC) {
+#endif /* CONFIG_MIPS_MT_SMTC */
+
+ configure_exception_vector();
/*
* Before R2 both interrupt numbers were fixed to 7, so on R2 only:
@@ -2185,3 +2203,32 @@ void __init trap_init(void)
cu2_notifier(default_cu2_call, 0x80000000); /* Run last */
}
+
+static int trap_pm_notifier(struct notifier_block *self, unsigned long cmd,
+ void *v)
+{
+ switch (cmd) {
+ case CPU_PM_ENTER_FAILED:
+ case CPU_PM_EXIT:
+ configure_status();
+ configure_hwrena();
+ configure_exception_vector();
+
+ /* Restore register with CPU number for TLB handlers */
+ TLBMISS_HANDLER_RESTORE();
+
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block trap_pm_notifier_block = {
+ .notifier_call = trap_pm_notifier,
+};
+
+static int __init trap_pm_init(void)
+{
+ return cpu_pm_register_notifier(&trap_pm_notifier_block);
+}
+arch_initcall(trap_pm_init);
--
1.8.5.3
