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[PATCH v12 2/3] irqchip/irq-goldfish-pic: Add Goldfish PIC driver

To: linux-mips@linux-mips.org
Subject: [PATCH v12 2/3] irqchip/irq-goldfish-pic: Add Goldfish PIC driver
From: Aleksandar Markovic <aleksandar.markovic@rt-rk.com>
Date: Fri, 29 Dec 2017 16:41:46 +0100
Cc: Miodrag Dinic <miodrag.dinic@mips.com>, Goran Ferenc <goran.ferenc@mips.com>, Aleksandar Markovic <aleksandar.markovic@mips.com>, "David S. Miller" <davem@davemloft.net>, Douglas Leung <douglas.leung@mips.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, James Hogan <james.hogan@mips.com>, Jason Cooper <jason@lakedaemon.net>, linux-kernel@vger.kernel.org, Marc Zyngier <marc.zyngier@arm.com>, Mauro Carvalho Chehab <mchehab@kernel.org>, Paul Burton <paul.burton@mips.com>, Petar Jovanovic <petar.jovanovic@mips.com>, Raghu Gandham <raghu.gandham@mips.com>, Randy Dunlap <rdunlap@infradead.org>, Thomas Gleixner <tglx@linutronix.de>
In-reply-to: <1514562138-13774-1-git-send-email-aleksandar.markovic@rt-rk.com>
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From: Miodrag Dinic <miodrag.dinic@mips.com>

Add device driver for a virtual programmable interrupt controller

The virtual PIC is designed as a device tree-based interrupt controller.

The compatible string used by OS for binding the driver is
"google,goldfish-pic".

Signed-off-by: Miodrag Dinic <miodrag.dinic@mips.com>
Signed-off-by: Goran Ferenc <goran.ferenc@mips.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@mips.com>
---
 MAINTAINERS                        |   1 +
 drivers/irqchip/Kconfig            |   8 +++
 drivers/irqchip/Makefile           |   1 +
 drivers/irqchip/irq-goldfish-pic.c | 139 +++++++++++++++++++++++++++++++++++++
 4 files changed, 149 insertions(+)
 create mode 100644 drivers/irqchip/irq-goldfish-pic.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 7152b90..e163873 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -871,6 +871,7 @@ ANDROID GOLDFISH PIC DRIVER
 M:     Miodrag Dinic <miodrag.dinic@mips.com>
 S:     Supported
 F:     
Documentation/devicetree/bindings/interrupt-controller/google,goldfish-pic.txt
+F:     drivers/irqchip/irq-goldfish-pic.c
 
 ANDROID GOLDFISH RTC DRIVER
 M:     Miodrag Dinic <miodrag.dinic@mips.com>
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index c70476b..d913aec 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -343,4 +343,12 @@ config MESON_IRQ_GPIO
        help
          Support Meson SoC Family GPIO Interrupt Multiplexer
 
+config GOLDFISH_PIC
+       bool "Goldfish programmable interrupt controller"
+       depends on MIPS && (GOLDFISH || COMPILE_TEST)
+       select IRQ_DOMAIN
+       help
+         Say yes here to enable Goldfish interrupt controller driver used
+         for Goldfish based virtual platforms.
+
 endmenu
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index d2df34a..d27e3e3 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -84,3 +84,4 @@ obj-$(CONFIG_QCOM_IRQ_COMBINER)               += 
qcom-irq-combiner.o
 obj-$(CONFIG_IRQ_UNIPHIER_AIDET)       += irq-uniphier-aidet.o
 obj-$(CONFIG_ARCH_SYNQUACER)           += irq-sni-exiu.o
 obj-$(CONFIG_MESON_IRQ_GPIO)           += irq-meson-gpio.o
+obj-$(CONFIG_GOLDFISH_PIC)             += irq-goldfish-pic.o
diff --git a/drivers/irqchip/irq-goldfish-pic.c 
b/drivers/irqchip/irq-goldfish-pic.c
new file mode 100644
index 0000000..2a92f03
--- /dev/null
+++ b/drivers/irqchip/irq-goldfish-pic.c
@@ -0,0 +1,139 @@
+/*
+ * Driver for MIPS Goldfish Programmable Interrupt Controller.
+ *
+ * Author: Miodrag Dinic <miodrag.dinic@mips.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#define GFPIC_NR_IRQS                  32
+
+/* 8..39 Cascaded Goldfish PIC interrupts */
+#define GFPIC_IRQ_BASE                 8
+
+#define GFPIC_REG_IRQ_PENDING          0x04
+#define GFPIC_REG_IRQ_DISABLE_ALL      0x08
+#define GFPIC_REG_IRQ_DISABLE          0x0c
+#define GFPIC_REG_IRQ_ENABLE           0x10
+
+struct goldfish_pic_data {
+       void __iomem *base;
+       struct irq_domain *irq_domain;
+};
+
+static void goldfish_pic_cascade(struct irq_desc *desc)
+{
+       struct goldfish_pic_data *gfpic = irq_desc_get_handler_data(desc);
+       struct irq_chip *host_chip = irq_desc_get_chip(desc);
+       u32 pending, hwirq, virq;
+
+       chained_irq_enter(host_chip, desc);
+
+       pending = readl(gfpic->base + GFPIC_REG_IRQ_PENDING);
+       while (pending) {
+               hwirq = __fls(pending);
+               virq = irq_linear_revmap(gfpic->irq_domain, hwirq);
+               generic_handle_irq(virq);
+               pending &= ~(1 << hwirq);
+       }
+
+       chained_irq_exit(host_chip, desc);
+}
+
+static const struct irq_domain_ops goldfish_irq_domain_ops = {
+       .xlate = irq_domain_xlate_onecell,
+};
+
+static int __init goldfish_pic_of_init(struct device_node *of_node,
+                                      struct device_node *parent)
+{
+       struct goldfish_pic_data *gfpic;
+       struct irq_chip_generic *gc;
+       struct irq_chip_type *ct;
+       unsigned int parent_irq;
+       int ret = 0;
+
+       gfpic = kzalloc(sizeof(*gfpic), GFP_KERNEL);
+       if (!gfpic) {
+               ret = -ENOMEM;
+               goto out_err;
+       }
+
+       parent_irq = irq_of_parse_and_map(of_node, 0);
+       if (!parent_irq) {
+               pr_err("Failed to map parent IRQ!\n");
+               ret = -EINVAL;
+               goto out_free;
+       }
+
+       gfpic->base = of_iomap(of_node, 0);
+       if (!gfpic->base) {
+               pr_err("Failed to map base address!\n");
+               ret = -ENOMEM;
+               goto out_unmap_irq;
+       }
+
+       /* Mask interrupts. */
+       writel(1, gfpic->base + GFPIC_REG_IRQ_DISABLE_ALL);
+
+       gc = irq_alloc_generic_chip("GFPIC", 1, GFPIC_IRQ_BASE, gfpic->base,
+                                   handle_level_irq);
+       if (!gc) {
+               pr_err("Failed to allocate chip structures!\n");
+               ret = -ENOMEM;
+               goto out_iounmap;
+       }
+
+       ct = gc->chip_types;
+       ct->regs.enable = GFPIC_REG_IRQ_ENABLE;
+       ct->regs.disable = GFPIC_REG_IRQ_DISABLE;
+       ct->chip.irq_unmask = irq_gc_unmask_enable_reg;
+       ct->chip.irq_mask = irq_gc_mask_disable_reg;
+
+       irq_setup_generic_chip(gc, IRQ_MSK(GFPIC_NR_IRQS), 0,
+                              IRQ_NOPROBE | IRQ_LEVEL, 0);
+
+       gfpic->irq_domain = irq_domain_add_legacy(of_node, GFPIC_NR_IRQS,
+                                                 GFPIC_IRQ_BASE, 0,
+                                                 &goldfish_irq_domain_ops,
+                                                 NULL);
+       if (!gfpic->irq_domain) {
+               pr_err("Failed to add irqdomain!\n");
+               ret = -ENOMEM;
+               goto out_destroy_generic_chip;
+       }
+
+       irq_set_chained_handler_and_data(parent_irq,
+                                        goldfish_pic_cascade, gfpic);
+
+       pr_info("Successfully registered.\n");
+       return 0;
+
+out_destroy_generic_chip:
+       irq_destroy_generic_chip(gc, IRQ_MSK(GFPIC_NR_IRQS),
+                                IRQ_NOPROBE | IRQ_LEVEL, 0);
+out_iounmap:
+       iounmap(gfpic->base);
+out_unmap_irq:
+       irq_dispose_mapping(parent_irq);
+out_free:
+       kfree(gfpic);
+out_err:
+       pr_err("Failed to initialize! (errno = %d)\n", ret);
+       return ret;
+}
+
+IRQCHIP_DECLARE(google_gf_pic, "google,goldfish-pic", goldfish_pic_of_init);
-- 
2.7.4


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