From: Sudeep KarkadaNagesha <sudeep.karkadanage...@arm.com>
This patch adds support for configuring the event stream frequency
and enabling it.
It also adds the hwcaps definitions to the user to detect this event
stream feature.
Cc: Russell King <li...@arm.linux.org.uk>
Cc: Lorenzo Pieralisi <lorenzo.pieral...@arm.com>
Acked-by: Catalin Marinas <catalin.mari...@arm.com>
Acked-by: Will Deacon <will.dea...@arm.com>
Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanage...@arm.com>
---
arch/arm/include/asm/arch_timer.h | 27 ++++++++++++++++++++++++---
arch/arm/include/uapi/asm/hwcap.h | 1 +
arch/arm/kernel/setup.c | 1 +
3 files changed, 26 insertions(+), 3 deletions(-)
diff --git a/arch/arm/include/asm/arch_timer.h
b/arch/arm/include/asm/arch_timer.h
index d57e04d..0704e0c 100644
--- a/arch/arm/include/asm/arch_timer.h
+++ b/arch/arm/include/asm/arch_timer.h
@@ -87,11 +87,21 @@ static inline u64 arch_counter_get_cntvct(void)
return cval;
}
-static inline void arch_counter_set_user_access(void)
+static inline u32 arch_timer_get_cntkctl(void)
{
u32 cntkctl;
-
asm volatile("mrc p15, 0, %0, c14, c1, 0" : "=r" (cntkctl));
+ return cntkctl;
+}
+
+static inline void arch_timer_set_cntkctl(u32 cntkctl)
+{
+ asm volatile("mcr p15, 0, %0, c14, c1, 0" : : "r" (cntkctl));
+}
+
+static inline void arch_counter_set_user_access(void)
+{
+ u32 cntkctl = arch_timer_get_cntkctl();
/* Disable user access to both physical/virtual counters/timers */
/* Also disable virtual event stream */
@@ -100,9 +110,20 @@ static inline void arch_counter_set_user_access(void)
| ARCH_TIMER_VIRT_EVT_EN
| ARCH_TIMER_USR_VCT_ACCESS_EN
| ARCH_TIMER_USR_PCT_ACCESS_EN);
+ arch_timer_set_cntkctl(cntkctl);
+}
- asm volatile("mcr p15, 0, %0, c14, c1, 0" : : "r" (cntkctl));
+static inline void arch_timer_evtstrm_enable(int divider)
+{
+ u32 cntkctl = arch_timer_get_cntkctl();
+ cntkctl &= ~ARCH_TIMER_EVT_TRIGGER_MASK;
+ /* Set the divider and enable virtual event stream */
+ cntkctl |= (divider << ARCH_TIMER_EVT_TRIGGER_SHIFT)
+ | ARCH_TIMER_VIRT_EVT_EN;
+ arch_timer_set_cntkctl(cntkctl);
+ elf_hwcap |= HWCAP_EVTSTRM;
}
+
#endif
#endif
diff --git a/arch/arm/include/uapi/asm/hwcap.h
b/arch/arm/include/uapi/asm/hwcap.h
index 6d34d08..7dcc10d 100644
--- a/arch/arm/include/uapi/asm/hwcap.h
+++ b/arch/arm/include/uapi/asm/hwcap.h
@@ -26,5 +26,6 @@
#define HWCAP_VFPD32 (1 << 19) /* set if VFP has 32 regs (not 16) */
#define HWCAP_IDIV (HWCAP_IDIVA | HWCAP_IDIVT)
#define HWCAP_LPAE (1 << 20)
+#define HWCAP_EVTSTRM (1 << 21)
#endif /* _UAPI__ASMARM_HWCAP_H */
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 0e1e2b3..5d65438 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -975,6 +975,7 @@ static const char *hwcap_str[] = {
"idivt",
"vfpd32",
"lpae",
+ "evtstrm",
NULL
};
--
1.8.1.2
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
