From: Nicolas Pitre <nicolas.pitre@linaro.org>
Date: Fri, 6 Jul 2012 01:33:26 +0000 (-0400)
Subject: ARM: bL_switcher: do not hardcode GIC IDs in the code
X-Git-Tag: firefly_0821_release~3680^2~238^2^2~19
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=eb3525e4e0279291d89546a1d8c240079943b8b2;p=firefly-linux-kernel-4.4.55.git

ARM: bL_switcher: do not hardcode GIC IDs in the code

Currently, GIC IDs are hardcoded making the code dependent on the x4 b.L
configuration.  Let's allow for GIC IDs to be discovered upon switcher
initialization to support other b.L configurations such as the x1 one.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
---

diff --git a/arch/arm/common/bL_switcher.c b/arch/arm/common/bL_switcher.c
index 460483473791..0d9ece547a12 100644
--- a/arch/arm/common/bL_switcher.c
+++ b/arch/arm/common/bL_switcher.c
@@ -111,6 +111,8 @@ static int bL_switchpoint(unsigned long _arg)
  * Generic switcher interface
  */
 
+static unsigned int bL_gic_id[MAX_CPUS_PER_CLUSTER][MAX_NR_CLUSTERS];
+
 /*
  * bL_switch_to - Switch to a specific cluster for the current CPU
  * @new_cluster_id: the ID of the cluster to switch to.
@@ -160,7 +162,7 @@ static int bL_switch_to(unsigned int new_cluster_id)
 	this_cpu = smp_processor_id();
 
 	/* redirect GIC's SGIs to our counterpart */
-	gic_migrate_target(cpuid + ib_cluster*4);
+	gic_migrate_target(bL_gic_id[cpuid][ib_cluster]);
 
 	/*
 	 * Raise a SGI on the inbound CPU to make sure it doesn't stall
@@ -340,6 +342,16 @@ static int __init bL_switcher_halve_cpus(void)
 		cluster = (cpu_logical_map(i) >> 8) & 0xff;
 
 		if (cpumask_test_cpu(cpu, &common_mask)) {
+			/* Let's take note of the GIC ID for this CPU */
+			int gic_id = gic_get_cpu_id(i);
+			if (gic_id < 0) {
+				pr_err("%s: bad GIC ID for CPU %d\n", __func__, i);
+				return -EINVAL;
+			}
+			bL_gic_id[cpu][cluster] = gic_id;
+			pr_info("GIC ID for CPU %u cluster %u is %u\n",
+				cpu, cluster, gic_id);
+
 			/*
 			 * We keep only those logical CPUs which number
 			 * is equal to their physical CPU number. This is
diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index c212513bffdf..29b876b98d44 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -667,6 +667,27 @@ void gic_raise_softirq(const struct cpumask *mask, unsigned int irq)
 #endif
 
 #ifdef CONFIG_BL_SWITCHER
+/*
+ * gic_get_cpu_id - get the CPU interface ID for the specified CPU
+ *
+ * @cpu: the logical CPU number to get the GIC ID for.
+ *
+ * Return the CPU interface ID for the given logical CPU number,
+ * or -1 if the CPU number is too large or the interface ID is
+ * unknown (more than one bit set).
+ */
+int gic_get_cpu_id(unsigned int cpu)
+{
+	unsigned int cpu_bit;
+
+	if (cpu >= NR_GIC_CPU_IF)
+		return -1;
+	cpu_bit = gic_cpu_map[cpu];
+	if (cpu_bit & (cpu_bit - 1))
+	       return -1;
+	return __ffs(cpu_bit);
+}
+
 /*
  * gic_migrate_target - migrate IRQs to another PU interface
  *
diff --git a/include/linux/irqchip/arm-gic.h b/include/linux/irqchip/arm-gic.h
index 40bfcac95940..2d7d47e8dfaf 100644
--- a/include/linux/irqchip/arm-gic.h
+++ b/include/linux/irqchip/arm-gic.h
@@ -75,6 +75,7 @@ static inline void gic_init(unsigned int nr, int start,
 	gic_init_bases(nr, start, dist, cpu, 0, NULL);
 }
 
+int gic_get_cpu_id(unsigned int cpu);
 void gic_migrate_target(unsigned int new_cpu_id);
 
 #endif /* __ASSEMBLY */