irqchip: move IRQ driver for Armada 370/XP

When the Marvell Armada 370/XP support was included in the kernel, the
drivers/irqchip/ directory didn't exist and the minimal infrastructure
in it also didn't exist. Now that we have those things in place, we
move the Armada 370/XP IRQ controller driver from
arch/arm/mach-mvebu/irq-armada-370-xp.c to
drivers/irqchip/irq-armada-370-xp.c.

Note in order to reduce code movement and therefore ease the review of
this patch, we intentionally introduce a forward declaration of
armada_370_xp_handle_irq(). It is in fact not needed because this
handler can now simply be implemented before
armada_370_xp_mpic_of_init(). That will be done in the next commit.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

2 files changed, 295 insertions, 0 deletions

diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 98e3b87..dae27a7 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -2,6 +2,7 @@ obj-$(CONFIG_IRQCHIP)			+= irqchip.o
 
 obj-$(CONFIG_ARCH_BCM2835)		+= irq-bcm2835.o
 obj-$(CONFIG_ARCH_EXYNOS)		+= exynos-combiner.o
+obj-$(CONFIG_ARCH_MVEBU)		+= irq-armada-370-xp.o
 obj-$(CONFIG_METAG)			+= irq-metag-ext.o
 obj-$(CONFIG_METAG_PERFCOUNTER_IRQS)	+= irq-metag.o
 obj-$(CONFIG_ARCH_SUNXI)		+= irq-sunxi.o
diff --git a/drivers/irqchip/irq-armada-370-xp.c b/drivers/irqchip/irq-armada-370-xp.c
new file mode 100644
index 0000000..d20a832
--- /dev/null
+++ b/drivers/irqchip/irq-armada-370-xp.c
@@ -0,0 +1,294 @@
+/*
+ * Marvell Armada 370 and Armada XP SoC IRQ handling
+ *
+ * Copyright (C) 2012 Marvell
+ *
+ * Lior Amsalem <alior@marvell.com>
+ * Gregory CLEMENT <gregory.clement@free-electrons.com>
+ * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+ * Ben Dooks <ben.dooks@codethink.co.uk>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/irqdomain.h>
+#include <asm/mach/arch.h>
+#include <asm/exception.h>
+#include <asm/smp_plat.h>
+#include <asm/mach/irq.h>
+
+#include "irqchip.h"
+
+/* Interrupt Controller Registers Map */
+#define ARMADA_370_XP_INT_SET_MASK_OFFS		(0x48)
+#define ARMADA_370_XP_INT_CLEAR_MASK_OFFS	(0x4C)
+
+#define ARMADA_370_XP_INT_CONTROL		(0x00)
+#define ARMADA_370_XP_INT_SET_ENABLE_OFFS	(0x30)
+#define ARMADA_370_XP_INT_CLEAR_ENABLE_OFFS	(0x34)
+#define ARMADA_370_XP_INT_SOURCE_CTL(irq)	(0x100 + irq*4)
+
+#define ARMADA_370_XP_CPU_INTACK_OFFS		(0x44)
+
+#define ARMADA_370_XP_SW_TRIG_INT_OFFS           (0x4)
+#define ARMADA_370_XP_IN_DRBEL_MSK_OFFS          (0xc)
+#define ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS        (0x8)
+
+#define ARMADA_370_XP_MAX_PER_CPU_IRQS		(28)
+
+#define ARMADA_370_XP_TIMER0_PER_CPU_IRQ	(5)
+
+#define ACTIVE_DOORBELLS			(8)
+
+static DEFINE_RAW_SPINLOCK(irq_controller_lock);
+
+static void __iomem *per_cpu_int_base;
+static void __iomem *main_int_base;
+static struct irq_domain *armada_370_xp_mpic_domain;
+
+/*
+ * In SMP mode:
+ * For shared global interrupts, mask/unmask global enable bit
+ * For CPU interrtups, mask/unmask the calling CPU's bit
+ */
+static void armada_370_xp_irq_mask(struct irq_data *d)
+{
+#ifdef CONFIG_SMP
+	irq_hw_number_t hwirq = irqd_to_hwirq(d);
+
+	if (hwirq != ARMADA_370_XP_TIMER0_PER_CPU_IRQ)
+		writel(hwirq, main_int_base +
+				ARMADA_370_XP_INT_CLEAR_ENABLE_OFFS);
+	else
+		writel(hwirq, per_cpu_int_base +
+				ARMADA_370_XP_INT_SET_MASK_OFFS);
+#else
+	writel(irqd_to_hwirq(d),
+	       per_cpu_int_base + ARMADA_370_XP_INT_SET_MASK_OFFS);
+#endif
+}
+
+static void armada_370_xp_irq_unmask(struct irq_data *d)
+{
+#ifdef CONFIG_SMP
+	irq_hw_number_t hwirq = irqd_to_hwirq(d);
+
+	if (hwirq != ARMADA_370_XP_TIMER0_PER_CPU_IRQ)
+		writel(hwirq, main_int_base +
+				ARMADA_370_XP_INT_SET_ENABLE_OFFS);
+	else
+		writel(hwirq, per_cpu_int_base +
+				ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
+#else
+	writel(irqd_to_hwirq(d),
+	       per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
+#endif
+}
+
+#ifdef CONFIG_SMP
+static int armada_xp_set_affinity(struct irq_data *d,
+				  const struct cpumask *mask_val, bool force)
+{
+	unsigned long reg;
+	unsigned long new_mask = 0;
+	unsigned long online_mask = 0;
+	unsigned long count = 0;
+	irq_hw_number_t hwirq = irqd_to_hwirq(d);
+	int cpu;
+
+	for_each_cpu(cpu, mask_val) {
+		new_mask |= 1 << cpu_logical_map(cpu);
+		count++;
+	}
+
+	/*
+	 * Forbid mutlicore interrupt affinity
+	 * This is required since the MPIC HW doesn't limit
+	 * several CPUs from acknowledging the same interrupt.
+	 */
+	if (count > 1)
+		return -EINVAL;
+
+	for_each_cpu(cpu, cpu_online_mask)
+		online_mask |= 1 << cpu_logical_map(cpu);
+
+	raw_spin_lock(&irq_controller_lock);
+
+	reg = readl(main_int_base + ARMADA_370_XP_INT_SOURCE_CTL(hwirq));
+	reg = (reg & (~online_mask)) | new_mask;
+	writel(reg, main_int_base + ARMADA_370_XP_INT_SOURCE_CTL(hwirq));
+
+	raw_spin_unlock(&irq_controller_lock);
+
+	return 0;
+}
+#endif
+
+static struct irq_chip armada_370_xp_irq_chip = {
+	.name		= "armada_370_xp_irq",
+	.irq_mask       = armada_370_xp_irq_mask,
+	.irq_mask_ack   = armada_370_xp_irq_mask,
+	.irq_unmask     = armada_370_xp_irq_unmask,
+#ifdef CONFIG_SMP
+	.irq_set_affinity = armada_xp_set_affinity,
+#endif
+};
+
+static int armada_370_xp_mpic_irq_map(struct irq_domain *h,
+				      unsigned int virq, irq_hw_number_t hw)
+{
+	armada_370_xp_irq_mask(irq_get_irq_data(virq));
+	writel(hw, main_int_base + ARMADA_370_XP_INT_SET_ENABLE_OFFS);
+	irq_set_status_flags(virq, IRQ_LEVEL);
+
+	if (hw == ARMADA_370_XP_TIMER0_PER_CPU_IRQ) {
+		irq_set_percpu_devid(virq);
+		irq_set_chip_and_handler(virq, &armada_370_xp_irq_chip,
+					handle_percpu_devid_irq);
+
+	} else {
+		irq_set_chip_and_handler(virq, &armada_370_xp_irq_chip,
+					handle_level_irq);
+	}
+	set_irq_flags(virq, IRQF_VALID | IRQF_PROBE);
+
+	return 0;
+}
+
+#ifdef CONFIG_SMP
+void armada_mpic_send_doorbell(const struct cpumask *mask, unsigned int irq)
+{
+	int cpu;
+	unsigned long map = 0;
+
+	/* Convert our logical CPU mask into a physical one. */
+	for_each_cpu(cpu, mask)
+		map |= 1 << cpu_logical_map(cpu);
+
+	/*
+	 * Ensure that stores to Normal memory are visible to the
+	 * other CPUs before issuing the IPI.
+	 */
+	dsb();
+
+	/* submit softirq */
+	writel((map << 8) | irq, main_int_base +
+		ARMADA_370_XP_SW_TRIG_INT_OFFS);
+}
+
+void armada_xp_mpic_smp_cpu_init(void)
+{
+	/* Clear pending IPIs */
+	writel(0, per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);
+
+	/* Enable first 8 IPIs */
+	writel((1 << ACTIVE_DOORBELLS) - 1, per_cpu_int_base +
+		ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
+
+	/* Unmask IPI interrupt */
+	writel(0, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
+}
+#endif /* CONFIG_SMP */
+
+static struct irq_domain_ops armada_370_xp_mpic_irq_ops = {
+	.map = armada_370_xp_mpic_irq_map,
+	.xlate = irq_domain_xlate_onecell,
+};
+
+static asmlinkage void __exception_irq_entry
+armada_370_xp_handle_irq(struct pt_regs *regs);
+
+static int __init armada_370_xp_mpic_of_init(struct device_node *node,
+					     struct device_node *parent)
+{
+	u32 control;
+
+	main_int_base = of_iomap(node, 0);
+	per_cpu_int_base = of_iomap(node, 1);
+
+	BUG_ON(!main_int_base);
+	BUG_ON(!per_cpu_int_base);
+
+	control = readl(main_int_base + ARMADA_370_XP_INT_CONTROL);
+
+	armada_370_xp_mpic_domain =
+		irq_domain_add_linear(node, (control >> 2) & 0x3ff,
+				&armada_370_xp_mpic_irq_ops, NULL);
+
+	if (!armada_370_xp_mpic_domain)
+		panic("Unable to add Armada_370_Xp MPIC irq domain (DT)\n");
+
+	irq_set_default_host(armada_370_xp_mpic_domain);
+
+#ifdef CONFIG_SMP
+	armada_xp_mpic_smp_cpu_init();
+
+	/*
+	 * Set the default affinity from all CPUs to the boot cpu.
+	 * This is required since the MPIC doesn't limit several CPUs
+	 * from acknowledging the same interrupt.
+	 */
+	cpumask_clear(irq_default_affinity);
+	cpumask_set_cpu(smp_processor_id(), irq_default_affinity);
+
+#endif
+
+	set_handle_irq(armada_370_xp_handle_irq);
+
+	return 0;
+}
+
+static asmlinkage void __exception_irq_entry
+armada_370_xp_handle_irq(struct pt_regs *regs)
+{
+	u32 irqstat, irqnr;
+
+	do {
+		irqstat = readl_relaxed(per_cpu_int_base +
+					ARMADA_370_XP_CPU_INTACK_OFFS);
+		irqnr = irqstat & 0x3FF;
+
+		if (irqnr > 1022)
+			break;
+
+		if (irqnr > 0) {
+			irqnr =	irq_find_mapping(armada_370_xp_mpic_domain,
+					irqnr);
+			handle_IRQ(irqnr, regs);
+			continue;
+		}
+#ifdef CONFIG_SMP
+		/* IPI Handling */
+		if (irqnr == 0) {
+			u32 ipimask, ipinr;
+
+			ipimask = readl_relaxed(per_cpu_int_base +
+						ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS)
+				& 0xFF;
+
+			writel(0x0, per_cpu_int_base +
+				ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);
+
+			/* Handle all pending doorbells */
+			for (ipinr = 0; ipinr < ACTIVE_DOORBELLS; ipinr++) {
+				if (ipimask & (0x1 << ipinr))
+					handle_IPI(ipinr, regs);
+			}
+			continue;
+		}
+#endif
+
+	} while (1);
+}
+
+IRQCHIP_DECLARE(armada_370_xp_mpic, "marvell,mpic", armada_370_xp_mpic_of_init);