aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorNicolas Pitre <nicolas.pitre@linaro.org>2012-04-12 01:40:31 -0400
committerNicolas Pitre <nicolas.pitre@linaro.org>2013-05-13 14:14:54 -0400
commit2ca74db3644d1f69ce40ae387d82b9db82938afc (patch)
tree1be930f4b996a40cdddeef629a0d3c03d5371217
parent70100a02268423b7bceafdf0ed6b0245f9baf7e8 (diff)
downloadvexpress-lsk-2ca74db3644d1f69ce40ae387d82b9db82938afc.tar.gz
ARM: gic: add CPU migration support
This is required by the big.LITTLE switcher code. The gic_migrate_target() changes the CPU interface mapping for the current CPU to redirect SGIs to the specified interface, and it also updates the target CPU for each interrupts to that CPU interface if they were targeting the current interface. Finally, pending SGIs for the current CPU are forwarded to the new interface. Because Linux does not use it, the SGI source information for the forwarded SGIs is not preserved. Neither is the source information for the SGIs sent by the current CPU to other CPUs adjusted to match the new CPU interface mapping. The required registers are banked so only the target CPU could do it. Signed-off-by: Nicolas Pitre <nico@linaro.org>
-rw-r--r--drivers/irqchip/irq-gic.c81
-rw-r--r--include/linux/irqchip/arm-gic.h4
2 files changed, 82 insertions, 3 deletions
diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index a32e0d5aa45..a64e871baa7 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -251,10 +251,9 @@ static int gic_set_affinity(struct irq_data *d, const struct cpumask *mask_val,
if (cpu >= NR_GIC_CPU_IF || cpu >= nr_cpu_ids)
return -EINVAL;
+ raw_spin_lock(&irq_controller_lock);
mask = 0xff << shift;
bit = gic_cpu_map[cpu] << shift;
-
- raw_spin_lock(&irq_controller_lock);
val = readl_relaxed(reg) & ~mask;
writel_relaxed(val | bit, reg);
raw_spin_unlock(&irq_controller_lock);
@@ -644,7 +643,9 @@ static void __init gic_pm_init(struct gic_chip_data *gic)
void gic_raise_softirq(const struct cpumask *mask, unsigned int irq)
{
int cpu;
- unsigned long map = 0;
+ unsigned long flags, map = 0;
+
+ raw_spin_lock_irqsave(&irq_controller_lock, flags);
/* Convert our logical CPU mask into a physical one. */
for_each_cpu(cpu, mask)
@@ -658,6 +659,80 @@ void gic_raise_softirq(const struct cpumask *mask, unsigned int irq)
/* this always happens on GIC0 */
writel_relaxed(map << 16 | irq, gic_data_dist_base(&gic_data[0]) + GIC_DIST_SOFTINT);
+
+ raw_spin_unlock_irqrestore(&irq_controller_lock, flags);
+}
+#endif
+
+#ifdef CONFIG_BL_SWITCHER
+/*
+ * gic_migrate_target - migrate IRQs to another PU interface
+ *
+ * @new_cpu_id: the CPU target ID to migrate IRQs to
+ *
+ * Migrate all peripheral interrupts with a target matching the current CPU
+ * to the interface corresponding to @new_cpu_id. The CPU interface mapping
+ * is also updated. Targets to other CPU interfaces are unchanged.
+ * This must be called with IRQs locally disabled.
+ */
+void gic_migrate_target(unsigned int new_cpu_id)
+{
+ unsigned int old_cpu_id, gic_irqs, gic_nr = 0;
+ void __iomem *dist_base;
+ int i, ror_val, cpu = smp_processor_id();
+ u32 val, old_mask, active_mask;
+
+ if (gic_nr >= MAX_GIC_NR)
+ BUG();
+
+ dist_base = gic_data_dist_base(&gic_data[gic_nr]);
+ if (!dist_base)
+ return;
+ gic_irqs = gic_data[gic_nr].gic_irqs;
+
+ old_cpu_id = __ffs(gic_cpu_map[cpu]);
+ old_mask = 0x01010101 << old_cpu_id;
+ ror_val = (old_cpu_id - new_cpu_id) & 31;
+
+ raw_spin_lock(&irq_controller_lock);
+
+ gic_cpu_map[cpu] = 1 << new_cpu_id;
+
+ for (i = 8; i < DIV_ROUND_UP(gic_irqs, 4); i++) {
+ val = readl_relaxed(dist_base + GIC_DIST_TARGET + i * 4);
+ active_mask = val & old_mask;
+ if (active_mask) {
+ val &= ~active_mask;
+ val |= ror32(active_mask, ror_val);
+ writel_relaxed(val, dist_base + GIC_DIST_TARGET + i * 4);
+ }
+ }
+
+ raw_spin_unlock(&irq_controller_lock);
+
+ /*
+ * Now let's migrate and clear any potential SGIs that might be
+ * pending for us (old_cpu_id). Since GIC_DIST_SGI_PENDING_SET
+ * is a banked register, we can only forward the SGI using
+ * GIC_DIST_SOFTINT. The original SGI source is lost but Linux
+ * doesn't use that information anyway.
+ *
+ * For the same reason we do not adjust SGI source information
+ * for previously sent SGIs by us to other CPUs either.
+ */
+ for (i = 0; i < 16; i += 4) {
+ int j;
+ val = readl_relaxed(dist_base + GIC_DIST_SGI_PENDING_SET + i);
+ if (!val)
+ continue;
+ writel_relaxed(val, dist_base + GIC_DIST_SGI_PENDING_CLEAR + i);
+ for (j = i; j < i + 4; j++) {
+ if (val & 0xff)
+ writel_relaxed((1 << (new_cpu_id + 16)) | j,
+ dist_base + GIC_DIST_SOFTINT);
+ val >>= 8;
+ }
+ }
}
#endif
diff --git a/include/linux/irqchip/arm-gic.h b/include/linux/irqchip/arm-gic.h
index 3fd8e4290a1..b1f802fbd18 100644
--- a/include/linux/irqchip/arm-gic.h
+++ b/include/linux/irqchip/arm-gic.h
@@ -31,6 +31,8 @@
#define GIC_DIST_TARGET 0x800
#define GIC_DIST_CONFIG 0xc00
#define GIC_DIST_SOFTINT 0xf00
+#define GIC_DIST_SGI_PENDING_CLEAR 0xf10
+#define GIC_DIST_SGI_PENDING_SET 0xf20
#define GICH_HCR 0x0
#define GICH_VTR 0x4
@@ -74,6 +76,8 @@ static inline void gic_init(unsigned int nr, int start,
gic_init_bases(nr, start, dist, cpu, 0, NULL);
}
+void gic_migrate_target(unsigned int new_cpu_id);
+
#endif /* __ASSEMBLY */
#endif