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