[PATCH v3 13/17] ARM64 / ACPI: Add GICv2 specific ACPI boot support

[Hanjun Guo <hanjun.guo@linaro.org>]

From: Tomasz Nowicki <tomasz.nowicki@linaro.org>

ACPI kernel uses MADT table for proper GIC initialization. It needs to
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 GICv1/2.

NOTE: This commit allow to initialize GICv1/2 only.

Signed-off-by: Tomasz Nowicki <tomasz.nowicki@linaro.org>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
---
 arch/arm64/include/asm/acpi.h        |    2 -
 arch/arm64/kernel/acpi.c             |   23 +++++++
 arch/arm64/kernel/irq.c              |    5 ++
 drivers/irqchip/irq-gic.c            |  114 ++++++++++++++++++++++++++++++++++
 include/linux/irqchip/arm-gic-acpi.h |   33 ++++++++++
 5 files changed, 175 insertions(+), 2 deletions(-)
 create mode 100644 include/linux/irqchip/arm-gic-acpi.h

diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index a867467..5d2ab63 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -97,8 +97,6 @@ void __init acpi_smp_init_cpus(void);
 extern int (*acpi_suspend_lowlevel)(void);
 #define acpi_wakeup_address 0
 
-#define ACPI_MAX_GIC_CPU_INTERFACE_ENTRIES 65535
-
 #else
 
 static inline bool acpi_psci_present(void) { return false; }
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index 354b912..b3b82b0 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -23,6 +23,7 @@
 #include <linux/irqdomain.h>
 #include <linux/bootmem.h>
 #include <linux/smp.h>
+#include <linux/irqchip/arm-gic-acpi.h>
 
 #include <asm/cputype.h>
 #include <asm/cpu_ops.h>
@@ -313,6 +314,28 @@ void __init acpi_boot_table_init(void)
 		pr_err("Can't find FADT or error happened during parsing FADT\n");
 }
 
+void __init acpi_gic_init(void)
+{
+	struct acpi_table_header *table;
+	acpi_status status;
+	acpi_size tbl_size;
+	int err;
+
+	status = acpi_get_table_with_size(ACPI_SIG_MADT, 0, &table, &tbl_size);
+	if (ACPI_FAILURE(status)) {
+		const char *msg = acpi_format_exception(status);
+
+		pr_err("Failed to get MADT table, %s\n", msg);
+		return;
+	}
+
+	err = gic_v2_acpi_init(table);
+	if (err)
+		pr_err("Failed to initialize GIC IRQ controller");
+
+	early_acpi_os_unmap_memory((char *)table, tbl_size);
+}
+
 /*
  * acpi_suspend_lowlevel() - save kernel state and suspend.
  *
diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
index 0f08dfd..c074d60 100644
--- a/arch/arm64/kernel/irq.c
+++ b/arch/arm64/kernel/irq.c
@@ -28,6 +28,7 @@
 #include <linux/irqchip.h>
 #include <linux/seq_file.h>
 #include <linux/ratelimit.h>
+#include <linux/irqchip/arm-gic-acpi.h>
 
 unsigned long irq_err_count;
 
@@ -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/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index 4b959e6..85cbf43 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -33,12 +33,14 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
+#include <linux/acpi.h>
 #include <linux/irqdomain.h>
 #include <linux/interrupt.h>
 #include <linux/percpu.h>
 #include <linux/slab.h>
 #include <linux/irqchip/chained_irq.h>
 #include <linux/irqchip/arm-gic.h>
+#include <linux/irqchip/arm-gic-acpi.h>
 
 #include <asm/cputype.h>
 #include <asm/irq.h>
@@ -1029,3 +1031,115 @@ IRQCHIP_DECLARE(msm_8660_qgic, "qcom,msm-8660-qgic", gic_of_init);
 IRQCHIP_DECLARE(msm_qgic2, "qcom,msm-qgic2", gic_of_init);
 
 #endif
+
+#ifdef CONFIG_ACPI
+static u64 dist_phy_base, cpu_phy_base = ULONG_MAX;
+
+static int __init
+gic_acpi_parse_madt_cpu(struct acpi_subtable_header *header,
+			const unsigned long end)
+{
+	struct acpi_madt_generic_interrupt *processor;
+	u64 gic_cpu_base;
+
+	processor = (struct acpi_madt_generic_interrupt *)header;
+
+	if (BAD_MADT_ENTRY(processor, end))
+		return -EINVAL;
+
+	gic_cpu_base = processor->base_address;
+	if (!gic_cpu_base)
+		return -EFAULT;
+
+	/*
+	 * There is no support for non-banked GICv1/2 register in ACPI spec.
+	 * All CPU interface addresses have to be the same.
+	 */
+	if (cpu_phy_base != ULONG_MAX && gic_cpu_base != cpu_phy_base)
+		return -EFAULT;
+
+	cpu_phy_base = gic_cpu_base;
+	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;
+
+	dist = (struct acpi_madt_generic_distributor *)header;
+
+	if (BAD_MADT_ENTRY(dist, end))
+		return -EINVAL;
+
+	dist_phy_base = dist->base_address;
+	if (!dist_phy_base)
+		return -EFAULT;
+
+	return 0;
+}
+
+int __init
+gic_v2_acpi_init(struct acpi_table_header *table)
+{
+	void __iomem *cpu_base, *dist_base;
+	int count;
+
+	/* Collect CPU base addresses */
+	count = acpi_parse_entries(sizeof(struct acpi_table_madt),
+				   gic_acpi_parse_madt_cpu, table,
+				   ACPI_MADT_TYPE_GENERIC_INTERRUPT,
+				   ACPI_MAX_GIC_CPU_INTERFACE_ENTRIES);
+	if (count < 0) {
+		pr_err("Error during GICC entries parsing\n");
+		return -EFAULT;
+	} else if (!count) {
+		/* No GICC entries provided, use address from MADT header */
+		struct acpi_table_madt *madt = (struct acpi_table_madt *)table;
+
+		if (!madt->address)
+			return -EFAULT;
+
+		cpu_phy_base = (u64)madt->address;
+	}
+
+	/*
+	 * Find distributor base address. We expect one distributor entry since
+	 * ACPI 5.1 spec neither support multi-GIC instances nor GIC cascade.
+	 */
+	count = acpi_parse_entries(sizeof(struct acpi_table_madt),
+				   gic_acpi_parse_madt_distributor, table,
+				   ACPI_MADT_TYPE_GENERIC_DISTRIBUTOR,
+				   ACPI_MAX_GIC_DISTRIBUTOR_ENTRIES);
+	if (count <= 0) {
+		pr_err("Error during GICD entries parsing\n");
+		return -EFAULT;
+	} else if (count > 1) {
+		pr_err("More than one GICD entry detected\n");
+		return -EINVAL;
+	}
+
+	cpu_base = ioremap(cpu_phy_base, ACPI_GIC_CPU_IF_MEM_SIZE);
+	if (!cpu_base) {
+		pr_err("Unable to map GICC registers\n");
+		return -ENOMEM;
+	}
+
+	dist_base = ioremap(dist_phy_base, ACPI_GIC_DIST_MEM_SIZE);
+	if (!dist_base) {
+		pr_err("Unable to map GICD registers\n");
+		iounmap(cpu_base);
+		return -ENOMEM;
+	}
+
+	/*
+	 * Initialize zero GIC instance (no multi-GIC support). Also, set GIC
+	 * as default IRQ domain to allow for GSI registration and GSI to IRQ
+	 * number translation (see acpi_register_gsi() and acpi_gsi_to_irq()).
+	 */
+	gic_init_bases(0, -1, dist_base, cpu_base, 0, NULL);
+	irq_set_default_host(gic_data[0].domain);
+	return 0;
+}
+#endif
diff --git a/include/linux/irqchip/arm-gic-acpi.h b/include/linux/irqchip/arm-gic-acpi.h
new file mode 100644
index 0000000..ce2ae1a8
--- /dev/null
+++ b/include/linux/irqchip/arm-gic-acpi.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2014, Linaro Ltd.
+ *	Author: Tomasz Nowicki <tomasz.nowicki@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef ARM_GIC_ACPI_H_
+#define ARM_GIC_ACPI_H_
+
+#include <linux/acpi.h>
+
+#ifdef CONFIG_ACPI
+#define ACPI_MAX_GIC_CPU_INTERFACE_ENTRIES	65535
+#define ACPI_MAX_GIC_DISTRIBUTOR_ENTRIES	1
+
+/*
+ * Hard code here, we can not get memory size from MADT (but FDT does),
+ * Actually no need to do that, because this size can be inferred
+ * from GIC spec.
+ */
+#define ACPI_GIC_DIST_MEM_SIZE		(SZ_64K)
+#define ACPI_GIC_CPU_IF_MEM_SIZE	(SZ_8K)
+
+void acpi_gic_init(void);
+int gic_v2_acpi_init(struct acpi_table_header *table);
+#else
+static inline void acpi_gic_init(void) { }
+#endif
+
+#endif /* ARM_GIC_ACPI_H_ */
-- 
1.7.9.5