drivers/perf: apple_m1: Refactor event select/filter configuration

Supporting guest mode events will necessitate programming two event
filters. Prepare by splitting up the programming of the event selector +
event filter into separate headers.

Opportunistically replace RMW patterns with sysreg_clear_set_s().

Tested-by: Janne Grunau <j@jannau.net>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250305202641.428114-2-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

drivers/perf/apple_m1_cpu_pmu.c

@@ -327,11 +327,10 @@ static void m1_pmu_disable_counter_interrupt(unsigned int index)
 	__m1_pmu_enable_counter_interrupt(index, false);
 }
 
-static void m1_pmu_configure_counter(unsigned int index, u8 event,
-				     bool user, bool kernel)
+static void __m1_pmu_configure_event_filter(unsigned int index, bool user,
+					    bool kernel)
 {
-	u64 val, user_bit, kernel_bit;
-	int shift;
+	u64 clear, set, user_bit, kernel_bit;
 
 	switch (index) {
 	case 0 ... 7:
@@ -346,19 +345,24 @@ static void m1_pmu_configure_counter(unsigned int index, u8 event,
 		BUG();
 	}
 
-	val = read_sysreg_s(SYS_IMP_APL_PMCR1_EL1);
-
+	clear = set = 0;
 	if (user)
-		val |= user_bit;
+		set |= user_bit;
 	else
-		val &= ~user_bit;
+		clear |= user_bit;
 
 	if (kernel)
-		val |= kernel_bit;
+		set |= kernel_bit;
 	else
-		val &= ~kernel_bit;
+		clear |= kernel_bit;
 
-	write_sysreg_s(val, SYS_IMP_APL_PMCR1_EL1);
+	sysreg_clear_set_s(SYS_IMP_APL_PMCR1_EL1, clear, set);
+}
+
+static void __m1_pmu_configure_eventsel(unsigned int index, u8 event)
+{
+	u64 clear = 0, set = 0;
+	int shift;
 
 	/*
 	 * Counters 0 and 1 have fixed events. For anything else,
@@ -371,21 +375,29 @@ static void m1_pmu_configure_counter(unsigned int index, u8 event,
 		break;
 	case 2 ... 5:
 		shift = (index - 2) * 8;
-		val = read_sysreg_s(SYS_IMP_APL_PMESR0_EL1);
-		val &= ~((u64)0xff << shift);
-		val |= (u64)event << shift;
-		write_sysreg_s(val, SYS_IMP_APL_PMESR0_EL1);
+		clear |= (u64)0xff << shift;
+		set |= (u64)event << shift;
+		sysreg_clear_set_s(SYS_IMP_APL_PMESR0_EL1, clear, set);
 		break;
 	case 6 ... 9:
 		shift = (index - 6) * 8;
-		val = read_sysreg_s(SYS_IMP_APL_PMESR1_EL1);
-		val &= ~((u64)0xff << shift);
-		val |= (u64)event << shift;
-		write_sysreg_s(val, SYS_IMP_APL_PMESR1_EL1);
+		clear |= (u64)0xff << shift;
+		set |= (u64)event << shift;
+		sysreg_clear_set_s(SYS_IMP_APL_PMESR1_EL1, clear, set);
 		break;
 	}
 }
 
+static void m1_pmu_configure_counter(unsigned int index, unsigned long config_base)
+{
+	bool kernel = config_base & M1_PMU_CFG_COUNT_KERNEL;
+	bool user = config_base & M1_PMU_CFG_COUNT_USER;
+	u8 evt = config_base & M1_PMU_CFG_EVENT;
+
+	__m1_pmu_configure_event_filter(index, user, kernel);
+	__m1_pmu_configure_eventsel(index, evt);
+}
+
 /* arm_pmu backend */
 static void m1_pmu_enable_event(struct perf_event *event)
 {
@@ -400,7 +412,7 @@ static void m1_pmu_enable_event(struct perf_event *event)
 	m1_pmu_disable_counter(event->hw.idx);
 	isb();
 
-	m1_pmu_configure_counter(event->hw.idx, evt, user, kernel);
+	m1_pmu_configure_counter(event->hw.idx, event->hw.config_base);
 	m1_pmu_enable_counter(event->hw.idx);
 	m1_pmu_enable_counter_interrupt(event->hw.idx);
 	isb();