1 files changed, 263 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-bcm2835.c b/drivers/irqchip/irq-bcm2835.c
new file mode 100644
index 0000000000..e94e288228
--- /dev/null
+++ b/drivers/irqchip/irq-bcm2835.c
@@ -0,0 +1,263 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2010 Broadcom
+ * Copyright 2012 Simon Arlott, Chris Boot, Stephen Warren
+ *
+ * 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/irqchip.h>
+#include <linux/irqdomain.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 FIQ_CONTROL_ENABLE	BIT(7)
+
+#define NR_BANKS		3
+#define IRQS_PER_BANK		32
+
+static const int reg_pending[] __initconst = { 0x00, 0x04, 0x08 };
+static const int reg_enable[] __initconst = { 0x18, 0x10, 0x14 };
+static const int reg_disable[] __initconst = { 0x24, 0x1c, 0x20 };
+static const 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 __exception_irq_entry bcm2835_handle_irq(
+	struct pt_regs *regs);
+static void bcm2836_chained_handle_irq(struct irq_desc *desc);
+
+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 const struct irq_domain_ops armctrl_ops = {
+	.xlate = armctrl_xlate
+};
+
+static int __init armctrl_of_init(struct device_node *node,
+				  struct device_node *parent,
+				  bool is_2836)
+{
+	void __iomem *base;
+	int irq, b, i;
+	u32 reg;
+
+	base = of_iomap(node, 0);
+	if (!base)
+		panic("%pOF: unable to map IC registers\n", node);
+
+	intc.domain = irq_domain_add_linear(node, MAKE_HWIRQ(NR_BANKS, 0),
+			&armctrl_ops, NULL);
+	if (!intc.domain)
+		panic("%pOF: unable to create IRQ domain\n", node);
+
+	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);
+			irq_set_probe(irq);
+		}
+
+		reg = readl_relaxed(intc.enable[b]);
+		if (reg) {
+			writel_relaxed(reg, intc.disable[b]);
+			pr_err(FW_BUG "Bootloader left irq enabled: "
+			       "bank %d irq %*pbl\n", b, IRQS_PER_BANK, &reg);
+		}
+	}
+
+	reg = readl_relaxed(base + REG_FIQ_CONTROL);
+	if (reg & FIQ_CONTROL_ENABLE) {
+		writel_relaxed(0, base + REG_FIQ_CONTROL);
+		pr_err(FW_BUG "Bootloader left fiq enabled\n");
+	}
+
+	if (is_2836) {
+		int parent_irq = irq_of_parse_and_map(node, 0);
+
+		if (!parent_irq) {
+			panic("%pOF: unable to get parent interrupt.\n",
+			      node);
+		}
+		irq_set_chained_handler(parent_irq, bcm2836_chained_handle_irq);
+	} else {
+		set_handle_irq(bcm2835_handle_irq);
+	}
+
+	return 0;
+}
+
+static int __init bcm2835_armctrl_of_init(struct device_node *node,
+					  struct device_node *parent)
+{
+	return armctrl_of_init(node, parent, false);
+}
+
+static int __init bcm2836_armctrl_of_init(struct device_node *node,
+					  struct device_node *parent)
+{
+	return armctrl_of_init(node, parent, true);
+}
+
+
+/*
+ * 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 u32 armctrl_translate_bank(int bank)
+{
+	u32 stat = readl_relaxed(intc.pending[bank]);
+
+	return MAKE_HWIRQ(bank, ffs(stat) - 1);
+}
+
+static u32 armctrl_translate_shortcut(int bank, u32 stat)
+{
+	return MAKE_HWIRQ(bank, shortcuts[ffs(stat >> SHORTCUT_SHIFT) - 1]);
+}
+
+static u32 get_next_armctrl_hwirq(void)
+{
+	u32 stat = readl_relaxed(intc.pending[0]) & BANK0_VALID_MASK;
+
+	if (stat == 0)
+		return ~0;
+	else if (stat & BANK0_HWIRQ_MASK)
+		return MAKE_HWIRQ(0, ffs(stat & BANK0_HWIRQ_MASK) - 1);
+	else if (stat & SHORTCUT1_MASK)
+		return armctrl_translate_shortcut(1, stat & SHORTCUT1_MASK);
+	else if (stat & SHORTCUT2_MASK)
+		return armctrl_translate_shortcut(2, stat & SHORTCUT2_MASK);
+	else if (stat & BANK1_HWIRQ)
+		return armctrl_translate_bank(1);
+	else if (stat & BANK2_HWIRQ)
+		return armctrl_translate_bank(2);
+	else
+		BUG();
+}
+
+static void __exception_irq_entry bcm2835_handle_irq(
+	struct pt_regs *regs)
+{
+	u32 hwirq;
+
+	while ((hwirq = get_next_armctrl_hwirq()) != ~0)
+		generic_handle_domain_irq(intc.domain, hwirq);
+}
+
+static void bcm2836_chained_handle_irq(struct irq_desc *desc)
+{
+	u32 hwirq;
+
+	while ((hwirq = get_next_armctrl_hwirq()) != ~0)
+		generic_handle_domain_irq(intc.domain, hwirq);
+}
+
+IRQCHIP_DECLARE(bcm2835_armctrl_ic, "brcm,bcm2835-armctrl-ic",
+		bcm2835_armctrl_of_init);
+IRQCHIP_DECLARE(bcm2836_armctrl_ic, "brcm,bcm2836-armctrl-ic",
+		bcm2836_armctrl_of_init);