arm64: arch_timer: simplify accessors

A while back we added {read,write}_sysreg accessors to handle accesses
to system registers, without the usual boilerplate asm volatile,
temporary variable, etc.

This patch makes use of these in the arm64 arch timer accessors to make
the code shorter and clearer.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/include/asm/arch_timer.h

@@ -20,6 +20,7 @@
 #define __ASM_ARCH_TIMER_H
 
 #include <asm/barrier.h>
+#include <asm/sysreg.h>
 
 #include <linux/bug.h>
 #include <linux/init.h>
@@ -38,19 +39,19 @@ void arch_timer_reg_write_cp15(int access, enum arch_timer_reg reg, u32 val)
 	if (access == ARCH_TIMER_PHYS_ACCESS) {
 		switch (reg) {
 		case ARCH_TIMER_REG_CTRL:
-			asm volatile("msr cntp_ctl_el0,  %0" : : "r" (val));
+			write_sysreg(val, cntp_ctl_el0);
 			break;
 		case ARCH_TIMER_REG_TVAL:
-			asm volatile("msr cntp_tval_el0, %0" : : "r" (val));
+			write_sysreg(val, cntp_tval_el0);
 			break;
 		}
 	} else if (access == ARCH_TIMER_VIRT_ACCESS) {
 		switch (reg) {
 		case ARCH_TIMER_REG_CTRL:
-			asm volatile("msr cntv_ctl_el0,  %0" : : "r" (val));
+			write_sysreg(val, cntv_ctl_el0);
 			break;
 		case ARCH_TIMER_REG_TVAL:
-			asm volatile("msr cntv_tval_el0, %0" : : "r" (val));
+			write_sysreg(val, cntv_tval_el0);
 			break;
 		}
 	}
@@ -61,48 +62,38 @@ void arch_timer_reg_write_cp15(int access, enum arch_timer_reg reg, u32 val)
 static __always_inline
 u32 arch_timer_reg_read_cp15(int access, enum arch_timer_reg reg)
 {
-	u32 val;
-
 	if (access == ARCH_TIMER_PHYS_ACCESS) {
 		switch (reg) {
 		case ARCH_TIMER_REG_CTRL:
-			asm volatile("mrs %0,  cntp_ctl_el0" : "=r" (val));
-			break;
+			return read_sysreg(cntp_ctl_el0);
 		case ARCH_TIMER_REG_TVAL:
-			asm volatile("mrs %0, cntp_tval_el0" : "=r" (val));
-			break;
+			return read_sysreg(cntp_tval_el0);
 		}
 	} else if (access == ARCH_TIMER_VIRT_ACCESS) {
 		switch (reg) {
 		case ARCH_TIMER_REG_CTRL:
-			asm volatile("mrs %0,  cntv_ctl_el0" : "=r" (val));
-			break;
+			return read_sysreg(cntv_ctl_el0);
 		case ARCH_TIMER_REG_TVAL:
-			asm volatile("mrs %0, cntv_tval_el0" : "=r" (val));
-			break;
+			return read_sysreg(cntv_tval_el0);
 		}
 	}
 
-	return val;
+	BUG();
 }
 
 static inline u32 arch_timer_get_cntfrq(void)
 {
-	u32 val;
-	asm volatile("mrs %0,   cntfrq_el0" : "=r" (val));
-	return val;
+	return read_sysreg(cntfrq_el0);
 }
 
 static inline u32 arch_timer_get_cntkctl(void)
 {
-	u32 cntkctl;
-	asm volatile("mrs	%0, cntkctl_el1" : "=r" (cntkctl));
-	return cntkctl;
+	return read_sysreg(cntkctl_el1);
 }
 
 static inline void arch_timer_set_cntkctl(u32 cntkctl)
 {
-	asm volatile("msr	cntkctl_el1, %0" : : "r" (cntkctl));
+	write_sysreg(cntkctl, cntkctl_el1);
 }
 
 static inline u64 arch_counter_get_cntpct(void)
@@ -116,12 +107,8 @@ static inline u64 arch_counter_get_cntpct(void)
 
 static inline u64 arch_counter_get_cntvct(void)
 {
-	u64 cval;
-
 	isb();
-	asm volatile("mrs %0, cntvct_el0" : "=r" (cval));
-
-	return cval;
+	return read_sysreg(cntvct_el0);
 }
 
 static inline int arch_timer_arch_init(void)