[PATCH v3 4/6] ARM64: arch_timer: configure and enable event stream

[Sudeep KarkadaNagesha]

From: Sudeep KarkadaNagesha <sudeep.karkadanagesha at 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 at arm.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
Signed-off-by: Will Deacon <will.deacon at arm.com>
[sudeep: moving ARM/ARM64 changes into separate patches]
Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha at arm.com>
---
 arch/arm64/include/asm/arch_timer.h | 15 +++++++++++++--
 arch/arm64/include/asm/hwcap.h      |  7 ++++++-
 arch/arm64/include/uapi/asm/hwcap.h |  1 +
 arch/arm64/kernel/setup.c           |  6 ++++++
 4 files changed, 26 insertions(+), 3 deletions(-)

Hi Will,

This is modified version enabling timer event stream hwcap compat dynamically.
Let me know if this looks fine.

Regards,
Sudeep

---->8---

diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h
index 69f5c8e..90f9d1a 100644
--- a/arch/arm64/include/asm/arch_timer.h
+++ b/arch/arm64/include/asm/arch_timer.h
@@ -106,14 +106,25 @@ 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;
+#ifdef CONFIG_COMPAT
+	compat_dyn_elf_hwcap |= COMPAT_HWCAP_EVTSTRM;
+#endif
+}
+
 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..022d771 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__
 /*
@@ -37,11 +38,15 @@
  * instruction set this cpu supports.
  */
 #define ELF_HWCAP		(elf_hwcap)
+#ifdef CONFIG_COMPAT
 #define COMPAT_ELF_HWCAP	(COMPAT_HWCAP_HALF|COMPAT_HWCAP_THUMB|\
 				 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_dyn_elf_hwcap)
+extern unsigned int compat_dyn_elf_hwcap;
+#endif
 
 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..91af65a 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -60,6 +60,11 @@ EXPORT_SYMBOL(processor_id);
 unsigned int elf_hwcap __read_mostly;
 EXPORT_SYMBOL_GPL(elf_hwcap);
 
+#ifdef CONFIG_COMPAT
+unsigned int compat_dyn_elf_hwcap __read_mostly = 0;
+EXPORT_SYMBOL_GPL(compat_dyn_elf_hwcap);
+#endif
+
 static const char *cpu_name;
 static const char *machine_name;
 phys_addr_t __fdt_pointer __initdata;
@@ -309,6 +314,7 @@ subsys_initcall(topology_init);
 static const char *hwcap_str[] = {
 	"fp",
 	"asimd",
+	"evtstrm",
 	NULL
 };
 
-- 
1.8.1.2