[RFC part2 PATCH 9/9] ACPI / GIC: Initialize GIC using the information in MADT

[Hanjun Guo]

In MADT table, there are GIC cpu interface base address and
GIC distributor base address, use them to convert GIC to ACPI.

Signed-off-by: Hanjun Guo <hanjun.guo at linaro.org>
---
 arch/arm64/kernel/irq.c      |    5 ++++
 drivers/acpi/plat/arm-core.c |   66 ++++++++++++++++++++++++++++++++++++------
 include/linux/acpi.h         |    6 ++++
 3 files changed, 68 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
index 473e5db..a9e68bf 100644
--- a/arch/arm64/kernel/irq.c
+++ b/arch/arm64/kernel/irq.c
@@ -25,6 +25,7 @@
 #include <linux/irq.h>
 #include <linux/smp.h>
 #include <linux/init.h>
+#include <linux/acpi.h>
 #include <linux/irqchip.h>
 #include <linux/seq_file.h>
 #include <linux/ratelimit.h>
@@ -78,6 +79,10 @@ void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
 void __init init_IRQ(void)
 {
 	irqchip_init();
+
+	if (!handle_arch_irq)
+		acpi_gic_init();
+
 	if (!handle_arch_irq)
 		panic("No interrupt controller found.");
 }
diff --git a/drivers/acpi/plat/arm-core.c b/drivers/acpi/plat/arm-core.c
index 17c99e1..509b847 100644
--- a/drivers/acpi/plat/arm-core.c
+++ b/drivers/acpi/plat/arm-core.c
@@ -29,6 +29,7 @@
 #include <linux/module.h>
 #include <linux/irq.h>
 #include <linux/irqdomain.h>
+#include <linux/irqchip/arm-gic.h>
 #include <linux/slab.h>
 #include <linux/bootmem.h>
 #include <linux/ioport.h>
@@ -211,11 +212,21 @@ acpi_parse_gic(struct acpi_subtable_header *header, const unsigned long end)
 	return 0;
 }
 
+#ifdef CONFIG_ARM_GIC
+/*
+ * Hard code here, we can not get memory size from MADT (but FDT does),
+ * this size is described in ARMv8 foudation model's User Guide
+ */
+#define GIC_DISTRIBUTOR_MEMORY_SIZE (SZ_8K)
+#define GIC_CPU_INTERFACE_MEMORY_SIZE (SZ_4K)
+
 static int __init
 acpi_parse_gic_distributor(struct acpi_subtable_header *header,
 				const unsigned long end)
 {
 	struct acpi_madt_generic_distributor *distributor = NULL;
+	void __iomem *dist_base = NULL;
+	void __iomem *cpu_base = NULL;
 
 	distributor = (struct acpi_madt_generic_distributor *)header;
 
@@ -224,8 +235,43 @@ acpi_parse_gic_distributor(struct acpi_subtable_header *header,
 
 	acpi_table_print_madt_entry(header);
 
+	/* GIC is initialised after page_init(), no need for early_ioremap */
+	dist_base = ioremap(distributor->base_address,
+				GIC_CPU_INTERFACE_MEMORY_SIZE);
+	if (!dist_base) {
+		pr_warn(PREFIX "unable to map gic dist registers\n");
+		return -ENOMEM;
+	}
+
+	/*
+	 * acpi_lapic_addr is stored in acpi_parse_madt(),
+	 * so we can use it here for GIC init
+	 */
+	if (acpi_lapic_addr) {
+		iounmap(dist_base);
+		pr_warn(PREFIX "Invalid GIC cpu interface base address\n");
+		return -EINVAL;
+	}
+
+	cpu_base = ioremap(acpi_lapic_addr, GIC_CPU_INTERFACE_MEMORY_SIZE);
+	if (!cpu_base) {
+		iounmap(dist_base);
+		pr_warn(PREFIX "unable to map gic cpu registers\n");
+		return -ENOMEM;
+	}
+
+	gic_init(distributor->gic_id, -1, dist_base, cpu_base);
+
 	return 0;
 }
+#else
+static int __init
+acpi_parse_gic_distributor(struct acpi_subtable_header *header,
+				const unsigned long end)
+{
+	return -ENODEV;
+}
+#endif /* CONFIG_ARM_GIC */
 
 /*
  * Parse GIC cpu interface related entries in MADT
@@ -234,7 +280,7 @@ acpi_parse_gic_distributor(struct acpi_subtable_header *header,
 static int __init acpi_parse_madt_gic_entries(void)
 {
 	int count;
-
+ 
 	/*
 	 * do a partial walk of MADT to determine how many CPUs
 	 * we have including disabled CPUs
@@ -468,19 +514,21 @@ static void __init acpi_process_madt(void)
 		 * Parse MADT GIC cpu interface entries
 		 */
 		error = acpi_parse_madt_gic_entries();
-		if (!error) {
-			/*
-			 * Parse MADT GIC distributor entries
-			 */
-			acpi_parse_madt_gic_distributor_entries();
-		}
+		if (!error)
+			pr_info("Using ACPI for processor (GIC) configuration information\n");
 	}
 
-	pr_info("Using ACPI for processor (GIC) configuration information\n");
-
 	return;
 }
 
+int __init acpi_gic_init(void)
+{
+	/*
+	 * Parse MADT GIC distributor entries
+	 */
+	return acpi_parse_madt_gic_distributor_entries();
+}
+
 /*
  * acpi_boot_table_init() and acpi_boot_init()
  *  called from setup_arch(), always.
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index edd5806..58a4bf4 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -112,6 +112,7 @@ char * __acpi_map_table (unsigned long phys_addr, unsigned long size);
 void __acpi_unmap_table(char *map, unsigned long size);
 int early_acpi_boot_init(void);
 int acpi_boot_init (void);
+int acpi_gic_init(void);
 void acpi_boot_table_init (void);
 int acpi_mps_check (void);
 int acpi_numa_init (void);
@@ -444,6 +445,11 @@ static inline int acpi_boot_init(void)
 	return 0;
 }
 
+static inline int acpi_gic_init(void)
+{
+	return -ENODEV;
+}
+
 static inline void acpi_boot_table_init(void)
 {
 	return;
-- 
1.7.9.5