[RFC PATCH 4/7] irqchip/apple-aic: Add support for Apple AIC

Mohamed Mediouni mohamed.mediouni at caramail.com
Wed Jan 20 08:27:14 EST 2021


From: Stan Skowronek <stan at corellium.com>

Apple SoCs use the Apple AIC interrupt controller.
The Arm architectural timers is wired over FIQ on that hardware.

Signed-off-by: Stan Skowronek <stan at corellium.com>
Signed-off-by: Mohamed Mediouni <mohamed.mediouni at caramail.com>
---
 .../interrupt-controller/apple,aic.yaml       |  49 ++++
 MAINTAINERS                                   |   6 +
 drivers/irqchip/Kconfig                       |   6 +
 drivers/irqchip/Makefile                      |   1 +
 drivers/irqchip/irq-apple-aic.c               | 211 ++++++++++++++++++
 5 files changed, 273 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/interrupt-controller/apple,aic.yaml
 create mode 100644 drivers/irqchip/irq-apple-aic.c

diff --git a/Documentation/devicetree/bindings/interrupt-controller/apple,aic.yaml b/Documentation/devicetree/bindings/interrupt-controller/apple,aic.yaml
new file mode 100644
index 000000000000..e615eaaca869
--- /dev/null
+++ b/Documentation/devicetree/bindings/interrupt-controller/apple,aic.yaml
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/interrupt-controller/apple,aic.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Apple Advanced Interrupt Controller (AIC)
+
+description:
+  Interrupt controller present on Apple processors. AIC
+  is used by Apple on their AArch64 SoCs since the Apple A7.
+
+maintainers:
+  - Stan Skowronek <stan at corellium.com>
+
+properties:
+  compatible:
+    items:
+      - const: apple,aic
+
+  reg:
+    maxItems: 1
+
+  '#interrupt-cells':
+    const: 3
+
+  interrupt-controller: true
+
+  fast-ipi:
+    description:
+      Fast IPI support.
+
+required:
+  - compatible
+  - '#interrupt-cells'
+  - interrupt-controller
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+        aic: interrupt-controller at 23b100000 {
+             compatible = "apple,aic";
+             #interrupt-cells = <3>;
+             interrupt-controller;
+             reg = <0x2 0x3b100000 0x0 0x8000>;
+             fast-ipi;
+         };
diff --git a/MAINTAINERS b/MAINTAINERS
index 00836f6452f0..e609ede99dd4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1218,6 +1218,12 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor
 F:	Documentation/admin-guide/LSM/apparmor.rst
 F:	security/apparmor/

+APPLE ADVANCED INTERRUPT CONTROLLER DRIVER
+M:	Stan Skowronek <stan at corellium.com>
+L:	linux-arm-kernel at lists.infradead.org
+S:	Maintained
+F:	drivers/irqchip/irq-apple-aic.c
+
 APPLE BCM5974 MULTITOUCH DRIVER
 M:	Henrik Rydberg <rydberg at bitmath.org>
 L:	linux-input at vger.kernel.org
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 94920a51c628..3aa9e711324b 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -56,6 +56,12 @@ config ARM_GIC_V3_ITS_FSL_MC
 	depends on FSL_MC_BUS
 	default ARM_GIC_V3_ITS

+config APPLE_AIC
+	bool
+	select IRQ_DOMAIN_HIERARCHY
+	select GENERIC_IRQ_MULTI_HANDLER
+	select GENERIC_IRQ_EFFECTIVE_AFF_MASK
+
 config ARM_NVIC
 	bool
 	select IRQ_DOMAIN_HIERARCHY
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 0ac93bfaec61..2f5a9a0cf40f 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_ARM_GIC_V3)		+= irq-gic-v3.o irq-gic-v3-mbi.o irq-gic-common.o
 obj-$(CONFIG_ARM_GIC_V3_ITS)		+= irq-gic-v3-its.o irq-gic-v3-its-platform-msi.o irq-gic-v4.o
 obj-$(CONFIG_ARM_GIC_V3_ITS_PCI)	+= irq-gic-v3-its-pci-msi.o
 obj-$(CONFIG_ARM_GIC_V3_ITS_FSL_MC)	+= irq-gic-v3-its-fsl-mc-msi.o
+obj-$(CONFIG_APPLE_AIC)			+= irq-apple-aic.o
 obj-$(CONFIG_PARTITION_PERCPU)		+= irq-partition-percpu.o
 obj-$(CONFIG_HISILICON_IRQ_MBIGEN)	+= irq-mbigen.o
 obj-$(CONFIG_ARM_NVIC)			+= irq-nvic.o
diff --git a/drivers/irqchip/irq-apple-aic.c b/drivers/irqchip/irq-apple-aic.c
new file mode 100644
index 000000000000..c601bc4b501a
--- /dev/null
+++ b/drivers/irqchip/irq-apple-aic.c
@@ -0,0 +1,211 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Apple chip interrupt controller
+ *
+ * Copyright (C) 2020 Corellium LLC
+ * Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
+ *
+ */
+
+#include <linux/interrupt.h>
+#include <linux/err.h>
+#include <linux/irqdomain.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#include <asm/exception.h>
+#include <asm/irq.h>
+
+#define REG_ID_REVISION 0x0000
+#define REG_ID_CONFIG 0x0004
+#define REG_GLOBAL_CFG 0x0010
+#define REG_TIME_LO 0x0020
+#define REG_TIME_HI 0x0028
+#define REG_ID_CPUID 0x2000
+#define REG_IRQ_ACK 0x2004
+#define REG_IRQ_ACK_TYPE_MASK (15 << 16)
+#define REG_IRQ_ACK_TYPE_NONE (0 << 16)
+#define REG_IRQ_ACK_TYPE_IRQ (1 << 16)
+#define REG_IRQ_ACK_TYPE_IPI (4 << 16)
+#define REG_IRQ_ACK_IPI_OTHER 0x40001
+#define REG_IRQ_ACK_IPI_SELF 0x40002
+#define REG_IRQ_ACK_NUM_MASK (4095)
+#define REG_IPI_SET 0x2008
+#define REG_IPI_FLAG_SELF (1 << 31)
+#define REG_IPI_FLAG_OTHER (1 << 0)
+#define REG_IPI_CLEAR 0x200C
+#define REG_IPI_DISABLE 0x2024
+#define REG_IPI_ENABLE 0x2028
+#define REG_IPI_DEFER_SET 0x202C
+#define REG_IPI_DEFER_CLEAR 0x2030
+#define REG_TSTAMP_CTRL 0x2040
+#define REG_TSTAMP_LO 0x2048
+#define REG_TSTAMP_HI 0x204C
+#define REG_IRQ_AFFINITY(i) (0x3000 + ((i) << 2))
+#define REG_IRQ_DISABLE(i) (0x4100 + (((i) >> 5) << 2))
+#define REG_IRQ_xABLE_MASK(i) (1 << ((i)&31))
+#define REG_IRQ_ENABLE(i) (0x4180 + (((i) >> 5) << 2))
+#define REG_CPU_REGION 0x5000
+#define REG_CPU_LOCAL 0x2000
+#define REG_CPU_SHIFT 7
+#define REG_PERCPU(r, c)                                                       \
+	((r) + REG_CPU_REGION - REG_CPU_LOCAL + ((c) << REG_CPU_SHIFT))
+
+static struct aic_chip_data {
+	void __iomem *base;
+	struct irq_domain *domain;
+	unsigned int num_irqs;
+} aic;
+
+static void apple_aic_irq_mask(struct irq_data *d)
+{
+	writel(REG_IRQ_xABLE_MASK(d->hwirq),
+	       aic.base + REG_IRQ_DISABLE(d->hwirq));
+}
+
+static void apple_aic_irq_unmask(struct irq_data *d)
+{
+	writel(REG_IRQ_xABLE_MASK(d->hwirq),
+	       aic.base + REG_IRQ_ENABLE(d->hwirq));
+}
+
+static struct irq_chip apple_aic_irq_chip = {
+	.name = "apple_aic",
+	.irq_mask = apple_aic_irq_mask,
+	.irq_mask_ack = apple_aic_irq_mask,
+	.irq_unmask = apple_aic_irq_unmask,
+};
+
+static void apple_aic_fiq_mask(struct irq_data *d)
+{
+}
+
+static void apple_aic_fiq_unmask(struct irq_data *d)
+{
+}
+
+static struct irq_chip apple_aic_irq_chip_fiq = {
+	.name = "apple_aic_fiq",
+	.irq_mask = apple_aic_fiq_mask,
+	.irq_unmask = apple_aic_fiq_unmask,
+};
+
+static int apple_aic_irq_domain_xlate(struct irq_domain *d,
+				      struct device_node *ctrlr,
+				      const u32 *intspec, unsigned int intsize,
+				      unsigned long *out_hwirq,
+				      unsigned int *out_type)
+{
+	if (intspec[0]) { /* FIQ */
+		if (intspec[1] >= 2)
+			return -EINVAL;
+		if (out_hwirq)
+			*out_hwirq = aic.num_irqs + intspec[1];
+	} else {
+		if (intspec[1] >= aic.num_irqs)
+			return -EINVAL;
+		if (out_hwirq)
+			*out_hwirq = intspec[1];
+	}
+
+	if (out_type)
+		*out_type = intspec[2] & IRQ_TYPE_SENSE_MASK;
+	return 0;
+}
+
+static int apple_aic_irq_domain_map(struct irq_domain *d, unsigned int virq,
+				    irq_hw_number_t hw)
+{
+	if (hw >= aic.num_irqs) {
+		irq_set_percpu_devid(virq);
+		irq_domain_set_info(d, virq, hw, &apple_aic_irq_chip_fiq,
+				    d->host_data, handle_percpu_devid_irq, NULL,
+				    NULL);
+		irq_set_status_flags(virq, IRQ_NOAUTOEN);
+	} else {
+		irq_domain_set_info(d, virq, hw, &apple_aic_irq_chip,
+				    d->host_data, handle_level_irq, NULL, NULL);
+		irq_set_probe(virq);
+		irqd_set_single_target(
+			irq_desc_get_irq_data(irq_to_desc(virq)));
+	}
+	return 0;
+}
+
+static const struct irq_domain_ops apple_aic_irq_domain_ops = {
+	.xlate = apple_aic_irq_domain_xlate,
+	.map = apple_aic_irq_domain_map,
+};
+
+static void __exception_irq_entry apple_aic_handle_irq(struct pt_regs *regs)
+{
+	uint32_t ack;
+	unsigned done = 0;
+
+	while (1) {
+		ack = readl(aic.base + REG_IRQ_ACK);
+		switch (ack & REG_IRQ_ACK_TYPE_MASK) {
+		case REG_IRQ_ACK_TYPE_NONE:
+			done = 1;
+			break;
+		case REG_IRQ_ACK_TYPE_IRQ:
+			handle_domain_irq(aic.domain,
+					  ack & REG_IRQ_ACK_NUM_MASK, regs);
+			break;
+		}
+		if (done)
+			break;
+	}
+}
+
+static void __exception_irq_entry apple_aic_handle_fiq(struct pt_regs *regs)
+{
+	handle_domain_irq(aic.domain, aic.num_irqs, regs);
+}
+
+void apple_aic_cpu_prepare(unsigned int cpu)
+{
+	unsigned i;
+
+	for (i = 0; i < aic.num_irqs; i++)
+		writel(readl(aic.base + REG_IRQ_AFFINITY(i)) | (1u << cpu),
+		       aic.base + REG_IRQ_AFFINITY(i));
+}
+
+static int __init apple_aic_init(struct device_node *node,
+				 struct device_node *interrupt_parent)
+{
+	unsigned i;
+
+	if (!node)
+		return -ENODEV;
+
+	aic.base = of_iomap(node, 0);
+	if (WARN(!aic.base, "unable to map aic registers\n"))
+		return -EINVAL;
+
+	aic.num_irqs = readl(aic.base + REG_ID_CONFIG) & 0xFFFF;
+	pr_info("Apple AIC: %d IRQs + 1 FIQ + 1 dummy\n", aic.num_irqs);
+
+	for (i = 0; i < aic.num_irqs; i++)
+		writel(1, aic.base + REG_IRQ_AFFINITY(i));
+	for (i = 0; i < aic.num_irqs; i += 32)
+		writel(-1u, aic.base + REG_IRQ_DISABLE(i));
+	writel((readl(aic.base + REG_GLOBAL_CFG) & ~0xF00000) | 0x700000,
+	       aic.base + REG_GLOBAL_CFG);
+
+	set_handle_irq(apple_aic_handle_irq);
+	set_handle_fiq(apple_aic_handle_fiq);
+
+	apple_aic_cpu_prepare(0);
+
+	aic.domain = irq_domain_add_linear(node, aic.num_irqs + 2,
+					   &apple_aic_irq_domain_ops,
+					   &apple_aic_irq_chip);
+	irq_set_default_host(aic.domain);
+	return 0;
+}
+
+IRQCHIP_DECLARE(apple_aic_irq_chip, "apple,aic", apple_aic_init);
--
2.29.2




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