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path: root/drivers/irqchip/irq-gic.c
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Diffstat (limited to 'drivers/irqchip/irq-gic.c')
-rw-r--r--drivers/irqchip/irq-gic.c71
1 files changed, 62 insertions, 9 deletions
diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index 651d726e8b12..f641e8e2c78d 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -1256,6 +1256,19 @@ static void gic_teardown(struct gic_chip_data *gic)
#ifdef CONFIG_OF
static int gic_cnt __initdata;
+static bool gicv2_force_probe;
+
+static int __init gicv2_force_probe_cfg(char *buf)
+{
+ return strtobool(buf, &gicv2_force_probe);
+}
+early_param("irqchip.gicv2_force_probe", gicv2_force_probe_cfg);
+
+static bool gic_check_gicv2(void __iomem *base)
+{
+ u32 val = readl_relaxed(base + GIC_CPU_IDENT);
+ return (val & 0xff0fff) == 0x02043B;
+}
static bool gic_check_eoimode(struct device_node *node, void __iomem **base)
{
@@ -1265,20 +1278,60 @@ static bool gic_check_eoimode(struct device_node *node, void __iomem **base)
if (!is_hyp_mode_available())
return false;
- if (resource_size(&cpuif_res) < SZ_8K)
- return false;
- if (resource_size(&cpuif_res) == SZ_128K) {
- u32 val_low, val_high;
+ if (resource_size(&cpuif_res) < SZ_8K) {
+ void __iomem *alt;
+ /*
+ * Check for a stupid firmware that only exposes the
+ * first page of a GICv2.
+ */
+ if (!gic_check_gicv2(*base))
+ return false;
+ if (!gicv2_force_probe) {
+ pr_warn("GIC: GICv2 detected, but range too small and irqchip.gicv2_force_probe not set\n");
+ return false;
+ }
+
+ alt = ioremap(cpuif_res.start, SZ_8K);
+ if (!alt)
+ return false;
+ if (!gic_check_gicv2(alt + SZ_4K)) {
+ /*
+ * The first page was that of a GICv2, and
+ * the second was *something*. Let's trust it
+ * to be a GICv2, and update the mapping.
+ */
+ pr_warn("GIC: GICv2 at %pa, but range is too small (broken DT?), assuming 8kB\n",
+ &cpuif_res.start);
+ iounmap(*base);
+ *base = alt;
+ return true;
+ }
+
+ /*
+ * We detected *two* initial GICv2 pages in a
+ * row. Could be a GICv2 aliased over two 64kB
+ * pages. Update the resource, map the iospace, and
+ * pray.
+ */
+ iounmap(alt);
+ alt = ioremap(cpuif_res.start, SZ_128K);
+ if (!alt)
+ return false;
+ pr_warn("GIC: Aliased GICv2 at %pa, trying to find the canonical range over 128kB\n",
+ &cpuif_res.start);
+ cpuif_res.end = cpuif_res.start + SZ_128K -1;
+ iounmap(*base);
+ *base = alt;
+ }
+ if (resource_size(&cpuif_res) == SZ_128K) {
/*
- * Verify that we have the first 4kB of a GIC400
+ * Verify that we have the first 4kB of a GICv2
* aliased over the first 64kB by checking the
* GICC_IIDR register on both ends.
*/
- val_low = readl_relaxed(*base + GIC_CPU_IDENT);
- val_high = readl_relaxed(*base + GIC_CPU_IDENT + 0xf000);
- if ((val_low & 0xffff0fff) != 0x0202043B ||
- val_low != val_high)
+ if (!gic_check_gicv2(*base) ||
+ !gic_check_gicv2(*base + 0xf000))
return false;
/*