[PATCH v4 13/21] arm/gic-v2: Add ACPI boot support for GICv2

[Shannon Zhao <zhaoshenglong@huawei.com>]

From: Parth Dixit <parth.dixit@linaro.org>

ACPI on Xen hypervisor uses MADT table for proper GIC initialization.
First get the GIC version from GIC Distributor. Then parse GIC related
subtables, collect CPU interface and distributor addresses and call
driver initialization function (which is hardware abstraction agnostic).
In a similar way, FDT initialize GICv2.

Signed-off-by: Parth Dixit <parth.dixit@linaro.org>
Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
---
V4: use container_of and fix coding style
---
 xen/arch/arm/gic-v2.c | 120 +++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 119 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/gic-v2.c b/xen/arch/arm/gic-v2.c
index 668b863..7e46ee9 100644
--- a/xen/arch/arm/gic-v2.c
+++ b/xen/arch/arm/gic-v2.c
@@ -29,6 +29,8 @@
 #include <xen/device_tree.h>
 #include <xen/libfdt/libfdt.h>
 #include <xen/sizes.h>
+#include <xen/acpi.h>
+#include <acpi/actables.h>
 #include <asm/p2m.h>
 #include <asm/domain.h>
 #include <asm/platform.h>
@@ -36,6 +38,7 @@
 
 #include <asm/io.h>
 #include <asm/gic.h>
+#include <asm/acpi.h>
 
 /*
  * LR register definitions are GIC v2 specific.
@@ -681,11 +684,111 @@ static void __init gicv2_dt_init(void)
                csize, vsize);
 }
 
+#ifdef CONFIG_ACPI
+static int __init
+gic_acpi_parse_madt_cpu(struct acpi_subtable_header *header,
+                        const unsigned long end)
+{
+    static int cpu_base_assigned = 0;
+    struct acpi_madt_generic_interrupt *processor =
+               container_of(header, struct acpi_madt_generic_interrupt, header);
+
+    if ( BAD_MADT_ENTRY(processor, end) )
+        return -EINVAL;
+
+    /* Read from APIC table and fill up the GIC variables */
+    if ( cpu_base_assigned == 0 )
+    {
+        cbase = processor->base_address;
+        csize = SZ_8K;
+        hbase = processor->gich_base_address;
+        vbase = processor->gicv_base_address;
+        gicv2_info.maintenance_irq = processor->vgic_interrupt;
+
+        if( processor->flags & ACPI_MADT_VGIC_IRQ_MODE )
+            irq_set_type(gicv2_info.maintenance_irq, IRQ_TYPE_EDGE_BOTH);
+        else
+            irq_set_type(gicv2_info.maintenance_irq, IRQ_TYPE_LEVEL_MASK);
+
+        cpu_base_assigned = 1;
+    }
+    else
+    {
+        if ( cbase != processor->base_address
+             || hbase != processor->gich_base_address
+             || vbase != processor->gicv_base_address
+             || gicv2_info.maintenance_irq != processor->vgic_interrupt )
+        {
+            printk("GICv2: GICC entries are not same in MADT table\n");
+            return -EINVAL;
+        }
+    }
+
+    return 0;
+}
+
+static int __init
+gic_acpi_parse_madt_distributor(struct acpi_subtable_header *header,
+                                const unsigned long end)
+{
+    struct acpi_madt_generic_distributor *dist =
+             container_of(header, struct acpi_madt_generic_distributor, header);
+
+    if ( BAD_MADT_ENTRY(dist, end) )
+        return -EINVAL;
+
+    dbase = dist->base_address;
+
+    return 0;
+}
+
+static void __init gicv2_acpi_init(void)
+{
+    acpi_status status;
+    struct acpi_table_header *table;
+    int count;
+
+    status = acpi_get_table(ACPI_SIG_MADT, 0, &table);
+
+    if ( ACPI_FAILURE(status) )
+    {
+        const char *msg = acpi_format_exception(status);
+
+        panic("GICv2: Failed to get MADT table, %s", msg);
+    }
+
+    /* Collect CPU base addresses */
+    count = acpi_parse_entries(ACPI_SIG_MADT, sizeof(struct acpi_table_madt),
+                               gic_acpi_parse_madt_cpu, table,
+                               ACPI_MADT_TYPE_GENERIC_INTERRUPT, 0);
+    if ( count <= 0 )
+        panic("GICv2: No valid GICC entries exists");
+
+    /*
+     * Find distributor base address. We expect one distributor entry since
+     * ACPI 5.0 spec neither support multi-GIC instances nor GIC cascade.
+     */
+    count = acpi_parse_entries(ACPI_SIG_MADT, sizeof(struct acpi_table_madt),
+                               gic_acpi_parse_madt_distributor, table,
+                               ACPI_MADT_TYPE_GENERIC_DISTRIBUTOR, 0);
+    if ( count <= 0 )
+        panic("GICv2: No valid GICD entries exists");
+}
+#else
+static void __init gicv2_acpi_init(void)
+{
+/* Should never reach here */
+}
+#endif
+
 static int __init gicv2_init(void)
 {
     uint32_t aliased_offset = 0;
 
-    gicv2_dt_init();
+    if ( acpi_disabled )
+        gicv2_dt_init();
+    else
+        gicv2_acpi_init();
 
     printk("GICv2 initialization:\n"
               "        gic_dist_addr=%"PRIpaddr"\n"
@@ -793,6 +896,21 @@ DT_DEVICE_START(gicv2, "GICv2", DEVICE_GIC)
         .init = gicv2_dt_preinit,
 DT_DEVICE_END
 
+#ifdef CONFIG_ACPI
+/* Set up the GIC */
+static int __init gicv2_acpi_preinit(const void *data)
+{
+    gicv2_info.hw_version = GIC_V2;
+    register_gic_ops(&gicv2_ops);
+
+    return 0;
+}
+
+ACPI_DEVICE_START(agicv2, "GICv2", DEVICE_GIC)
+        .class_type = ACPI_MADT_GIC_VERSION_V2,
+        .init = gicv2_acpi_preinit,
+ACPI_DEVICE_END
+#endif
 /*
  * Local variables:
  * mode: C
-- 
2.0.4