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Subject[PATCH v3 4/6] ARM64: arch_timer: configure and enable event stream
Date
From: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>

This patch configures the event stream frequency and enables it.
It also adds the hwcaps as well as compat-specific definitions to
the user to detect this event stream feature.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
[sudeep: moving ARM/ARM64 changes into separate patches]
Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
---
arch/arm64/include/asm/arch_timer.h | 12 ++++++++++--
arch/arm64/include/asm/hwcap.h | 4 +++-
arch/arm64/include/uapi/asm/hwcap.h | 1 +
arch/arm64/kernel/setup.c | 1 +
4 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h
index 69f5c8e..43f322a 100644
--- a/arch/arm64/include/asm/arch_timer.h
+++ b/arch/arm64/include/asm/arch_timer.h
@@ -106,14 +106,22 @@ static inline void arch_counter_set_user_access(int divider)
/* Disable user access to the timers and the physical counter. */
cntkctl &= ~(ARCH_TIMER_USR_PT_ACCESS_EN
| ARCH_TIMER_USR_VT_ACCESS_EN
+ | ARCH_TIMER_EVT_TRIGGER_MASK
| ARCH_TIMER_USR_PCT_ACCESS_EN);

- /* Enable user access to the virtual counter. */
- cntkctl |= ARCH_TIMER_USR_VCT_ACCESS_EN;
+ /* Enable event stream and user access to the virtual counter */
+ cntkctl |= (divider << ARCH_TIMER_EVT_TRIGGER_SHIFT)
+ | ARCH_TIMER_VIRT_EVT_EN
+ | ARCH_TIMER_USR_VCT_ACCESS_EN;

asm volatile("msr cntkctl_el1, %0" : : "r" (cntkctl));
}

+static inline void arch_timer_set_hwcap_evtstrm(void)
+{
+ elf_hwcap |= HWCAP_EVTSTRM;
+}
+
static inline u64 arch_counter_get_cntvct(void)
{
u64 cval;
diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
index 6d4482f..effd8f9 100644
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -30,6 +30,7 @@
#define COMPAT_HWCAP_IDIVA (1 << 17)
#define COMPAT_HWCAP_IDIVT (1 << 18)
#define COMPAT_HWCAP_IDIV (COMPAT_HWCAP_IDIVA|COMPAT_HWCAP_IDIVT)
+#define COMPAT_HWCAP_EVTSTRM (1 << 21)

#ifndef __ASSEMBLY__
/*
@@ -41,7 +42,8 @@
COMPAT_HWCAP_FAST_MULT|COMPAT_HWCAP_EDSP|\
COMPAT_HWCAP_TLS|COMPAT_HWCAP_VFP|\
COMPAT_HWCAP_VFPv3|COMPAT_HWCAP_VFPv4|\
- COMPAT_HWCAP_NEON|COMPAT_HWCAP_IDIV)
+ COMPAT_HWCAP_NEON|COMPAT_HWCAP_IDIV|\
+ COMPAT_HWCAP_EVTSTRM)

extern unsigned int elf_hwcap;
#endif
diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h
index eea4975..9b12476 100644
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -21,6 +21,7 @@
*/
#define HWCAP_FP (1 << 0)
#define HWCAP_ASIMD (1 << 1)
+#define HWCAP_EVTSTRM (1 << 2)


#endif /* _UAPI__ASM_HWCAP_H */
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index add6ea6..1111833 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -309,6 +309,7 @@ subsys_initcall(topology_init);
static const char *hwcap_str[] = {
"fp",
"asimd",
+ "evtstrm",
NULL
};

--
1.8.1.2



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