1 files changed, 223 insertions, 0 deletions

diff --git a/drivers/irqchip/irq-bcm2835.c b/drivers/irqchip/irq-bcm2835.c
new file mode 100644
index 000000000000..dc670ccc6978
--- /dev/null
+++ b/drivers/irqchip/irq-bcm2835.c
@@ -0,0 +1,223 @@
+/*
+ * Copyright 2010 Broadcom
+ * Copyright 2012 Simon Arlott, Chris Boot, Stephen Warren
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Quirk 1: Shortcut interrupts don't set the bank 1/2 register pending bits
+ *
+ * If an interrupt fires on bank 1 that isn't in the shortcuts list, bit 8
+ * on bank 0 is set to signify that an interrupt in bank 1 has fired, and
+ * to look in the bank 1 status register for more information.
+ *
+ * If an interrupt fires on bank 1 that _is_ in the shortcuts list, its
+ * shortcut bit in bank 0 is set as well as its interrupt bit in the bank 1
+ * status register, but bank 0 bit 8 is _not_ set.
+ *
+ * Quirk 2: You can't mask the register 1/2 pending interrupts
+ *
+ * In a proper cascaded interrupt controller, the interrupt lines with
+ * cascaded interrupt controllers on them are just normal interrupt lines.
+ * You can mask the interrupts and get on with things. With this controller
+ * you can't do that.
+ *
+ * Quirk 3: The shortcut interrupts can't be (un)masked in bank 0
+ *
+ * Those interrupts that have shortcuts can only be masked/unmasked in
+ * their respective banks' enable/disable registers. Doing so in the bank 0
+ * enable/disable registers has no effect.
+ *
+ * The FIQ control register:
+ *  Bits 0-6: IRQ (index in order of interrupts from banks 1, 2, then 0)
+ *  Bit    7: Enable FIQ generation
+ *  Bits  8+: Unused
+ *
+ * An interrupt must be disabled before configuring it for FIQ generation
+ * otherwise both handlers will fire at the same time!
+ */
+
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/irqchip/bcm2835.h>
+
+#include <asm/exception.h>
+
+/* Put the bank and irq (32 bits) into the hwirq */
+#define MAKE_HWIRQ(b, n)        ((b << 5) | (n))
+#define HWIRQ_BANK(i)           (i >> 5)
+#define HWIRQ_BIT(i)            BIT(i & 0x1f)
+
+#define NR_IRQS_BANK0           8
+#define BANK0_HWIRQ_MASK        0xff
+/* Shortcuts can't be disabled so any unknown new ones need to be masked */
+#define SHORTCUT1_MASK          0x00007c00
+#define SHORTCUT2_MASK          0x001f8000
+#define SHORTCUT_SHIFT          10
+#define BANK1_HWIRQ             BIT(8)
+#define BANK2_HWIRQ             BIT(9)
+#define BANK0_VALID_MASK        (BANK0_HWIRQ_MASK | BANK1_HWIRQ | BANK2_HWIRQ \
+                                        | SHORTCUT1_MASK | SHORTCUT2_MASK)
+
+#define REG_FIQ_CONTROL         0x0c
+
+#define NR_BANKS                3
+#define IRQS_PER_BANK           32
+
+static int reg_pending[] __initconst = { 0x00, 0x04, 0x08 };
+static int reg_enable[] __initconst = { 0x18, 0x10, 0x14 };
+static int reg_disable[] __initconst = { 0x24, 0x1c, 0x20 };
+static int bank_irqs[] __initconst = { 8, 32, 32 };
+
+static const int shortcuts[] = {
+        7, 9, 10, 18, 19,               /* Bank 1 */
+        21, 22, 23, 24, 25, 30          /* Bank 2 */
+};
+
+struct armctrl_ic {
+        void __iomem *base;
+        void __iomem *pending[NR_BANKS];
+        void __iomem *enable[NR_BANKS];
+        void __iomem *disable[NR_BANKS];
+        struct irq_domain *domain;
+};
+
+static struct armctrl_ic intc __read_mostly;
+
+static void armctrl_mask_irq(struct irq_data *d)
+{
+        writel_relaxed(HWIRQ_BIT(d->hwirq), intc.disable[HWIRQ_BANK(d->hwirq)]);
+}
+
+static void armctrl_unmask_irq(struct irq_data *d)
+{
+        writel_relaxed(HWIRQ_BIT(d->hwirq), intc.enable[HWIRQ_BANK(d->hwirq)]);
+}
+
+static struct irq_chip armctrl_chip = {
+        .name = "ARMCTRL-level",
+        .irq_mask = armctrl_mask_irq,
+        .irq_unmask = armctrl_unmask_irq
+};
+
+static int armctrl_xlate(struct irq_domain *d, struct device_node *ctrlr,
+        const u32 *intspec, unsigned int intsize,
+        unsigned long *out_hwirq, unsigned int *out_type)
+{
+        if (WARN_ON(intsize != 2))
+                return -EINVAL;
+
+        if (WARN_ON(intspec[0] >= NR_BANKS))
+                return -EINVAL;
+
+        if (WARN_ON(intspec[1] >= IRQS_PER_BANK))
+                return -EINVAL;
+
+        if (WARN_ON(intspec[0] == 0 && intspec[1] >= NR_IRQS_BANK0))
+                return -EINVAL;
+
+        *out_hwirq = MAKE_HWIRQ(intspec[0], intspec[1]);
+        *out_type = IRQ_TYPE_NONE;
+        return 0;
+}
+
+static struct irq_domain_ops armctrl_ops = {
+        .xlate = armctrl_xlate
+};
+
+static int __init armctrl_of_init(struct device_node *node,
+        struct device_node *parent)
+{
+        void __iomem *base;
+        int irq, b, i;
+
+        base = of_iomap(node, 0);
+        if (!base)
+                panic("%s: unable to map IC registers\n",
+                        node->full_name);
+
+        intc.domain = irq_domain_add_linear(node, MAKE_HWIRQ(NR_BANKS, 0),
+                        &armctrl_ops, NULL);
+        if (!intc.domain)
+                panic("%s: unable to create IRQ domain\n", node->full_name);
+
+        for (b = 0; b < NR_BANKS; b++) {
+                intc.pending[b] = base + reg_pending[b];
+                intc.enable[b] = base + reg_enable[b];
+                intc.disable[b] = base + reg_disable[b];
+
+                for (i = 0; i < bank_irqs[b]; i++) {
+                        irq = irq_create_mapping(intc.domain, MAKE_HWIRQ(b, i));
+                        BUG_ON(irq <= 0);
+                        irq_set_chip_and_handler(irq, &armctrl_chip,
+                                handle_level_irq);
+                        set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
+                }
+        }
+        return 0;
+}
+
+static struct of_device_id irq_of_match[] __initconst = {
+        { .compatible = "brcm,bcm2835-armctrl-ic", .data = armctrl_of_init }
+};
+
+void __init bcm2835_init_irq(void)
+{
+        of_irq_init(irq_of_match);
+}
+
+/*
+ * Handle each interrupt across the entire interrupt controller.  This reads the
+ * status register before handling each interrupt, which is necessary given that
+ * handle_IRQ may briefly re-enable interrupts for soft IRQ handling.
+ */
+
+static void armctrl_handle_bank(int bank, struct pt_regs *regs)
+{
+        u32 stat, irq;
+
+        while ((stat = readl_relaxed(intc.pending[bank]))) {
+                irq = MAKE_HWIRQ(bank, ffs(stat) - 1);
+                handle_IRQ(irq_linear_revmap(intc.domain, irq), regs);
+        }
+}
+
+static void armctrl_handle_shortcut(int bank, struct pt_regs *regs,
+        u32 stat)
+{
+        u32 irq = MAKE_HWIRQ(bank, shortcuts[ffs(stat >> SHORTCUT_SHIFT) - 1]);
+        handle_IRQ(irq_linear_revmap(intc.domain, irq), regs);
+}
+
+asmlinkage void __exception_irq_entry bcm2835_handle_irq(
+        struct pt_regs *regs)
+{
+        u32 stat, irq;
+
+        while ((stat = readl_relaxed(intc.pending[0]) & BANK0_VALID_MASK)) {
+                if (stat & BANK0_HWIRQ_MASK) {
+                        irq = MAKE_HWIRQ(0, ffs(stat & BANK0_HWIRQ_MASK) - 1);
+                        handle_IRQ(irq_linear_revmap(intc.domain, irq), regs);
+                } else if (stat & SHORTCUT1_MASK) {
+                        armctrl_handle_shortcut(1, regs, stat & SHORTCUT1_MASK);
+                } else if (stat & SHORTCUT2_MASK) {
+                        armctrl_handle_shortcut(2, regs, stat & SHORTCUT2_MASK);
+                } else if (stat & BANK1_HWIRQ) {
+                        armctrl_handle_bank(1, regs);
+                } else if (stat & BANK2_HWIRQ) {
+                        armctrl_handle_bank(2, regs);
+                } else {
+                        BUG();
+                }
+        }
+}