[PATCH 01/18] irqchip: vf610-gpc: add Vybrid GPC IRQ controller

[Stefan Agner]

This patch introduces a driver for Vybrids GPC (Global Power
Controller). Vybrids GPC IP is simpler than the one found in
i.MX 6: There is no power gating control (GPC) and the GPC INTC
does not need to clear IRQ masks for an interrupt to get routed
to the GIC (the mask only applys for wake-up control).

Signed-off-by: Stefan Agner <stefan at agner.ch>
---
 drivers/irqchip/Makefile        |   1 +
 drivers/irqchip/irq-vf610-gpc.c | 138 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 139 insertions(+)
 create mode 100644 drivers/irqchip/irq-vf610-gpc.c

diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 18caacb..0a77ac6 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -45,6 +45,7 @@ obj-$(CONFIG_TS4800_IRQ)		+= irq-ts4800.o
 obj-$(CONFIG_XTENSA)			+= irq-xtensa-pic.o
 obj-$(CONFIG_XTENSA_MX)			+= irq-xtensa-mx.o
 obj-$(CONFIG_IRQ_CROSSBAR)		+= irq-crossbar.o
+obj-$(CONFIG_SOC_VF610)			+= irq-vf610-gpc.o
 obj-$(CONFIG_SOC_VF610)			+= irq-vf610-mscm-ir.o
 obj-$(CONFIG_BCM7038_L1_IRQ)		+= irq-bcm7038-l1.o
 obj-$(CONFIG_BCM7120_L2_IRQ)		+= irq-bcm7120-l2.o
diff --git a/drivers/irqchip/irq-vf610-gpc.c b/drivers/irqchip/irq-vf610-gpc.c
new file mode 100644
index 0000000..2c6a043
--- /dev/null
+++ b/drivers/irqchip/irq-vf610-gpc.c
@@ -0,0 +1,138 @@
+/*
+ * Copyright (C) 2016 Toradex AG
+ * Author: Stefan Agner <stefan at agner.ch>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ *
+ * The GPC (General Power Controller) irqchip driver takes care of the
+ * interrupt wakeup functionality.
+ *
+ * o All peripheral interrupts of the Vybrid SoC can be used as wakeup
+ *   source from STOP mode. In LPSTOP mode however, the GPC is unpowered
+ *   too and cannot be used to as a wakeup source. The WKPU (Wakeup Unit)
+ *   is responsible for wakeups from LPSTOP modes.
+ */
+
+#include <linux/cpu_pm.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/mfd/syscon.h>
+#include <dt-bindings/interrupt-controller/arm-gic.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+#include <linux/regmap.h>
+
+#define IMR_NUM			4
+#define VF610_GPC_IMR1		0x044
+#define VF610_GPC_MAX_IRQS	(IMR_NUM * 32)
+
+static void __iomem *gpc_base;
+
+static int vf610_gpc_irq_set_wake(struct irq_data *d, unsigned int on)
+{
+	unsigned int idx = d->hwirq / 32;
+	void __iomem *reg_imr = gpc_base + VF610_GPC_IMR1 + (idx * 4);
+	u32 mask = 1 << d->hwirq % 32;
+
+	if (on)
+		writel_relaxed(readl_relaxed(reg_imr) & ~mask, reg_imr);
+	else
+		writel_relaxed(readl_relaxed(reg_imr) | mask, reg_imr);
+
+	/*
+	 * Do *not* call into the parent, as the GIC doesn't have any
+	 * wake-up facility...
+	 */
+	return 0;
+}
+
+static struct irq_chip vf610_gpc_chip = {
+	.name			= "vf610-gpc",
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+	.irq_enable		= irq_chip_enable_parent,
+	.irq_disable		= irq_chip_disable_parent,
+	.irq_eoi		= irq_chip_eoi_parent,
+	.irq_retrigger		= irq_chip_retrigger_hierarchy,
+	.irq_set_wake		= vf610_gpc_irq_set_wake,
+};
+
+static int vf610_gpc_domain_alloc(struct irq_domain *domain, unsigned int virq,
+				  unsigned int nr_irqs, void *arg)
+{
+	int i;
+	irq_hw_number_t hwirq;
+	struct irq_fwspec *fwspec = arg;
+	struct irq_fwspec parent_fwspec;
+
+	if (!irq_domain_get_of_node(domain->parent))
+		return -EINVAL;
+
+	if (fwspec->param_count != 2)
+		return -EINVAL;
+
+	hwirq = fwspec->param[0];
+	for (i = 0; i < nr_irqs; i++)
+		irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
+					      &vf610_gpc_chip, NULL);
+
+	parent_fwspec = *fwspec;
+	parent_fwspec.fwnode = domain->parent->fwnode;
+	return irq_domain_alloc_irqs_parent(domain, virq, nr_irqs,
+					    &parent_fwspec);
+}
+
+static int vf610_gpc_domain_translate(struct irq_domain *d,
+					  struct irq_fwspec *fwspec,
+					  unsigned long *hwirq,
+					  unsigned int *type)
+{
+	if (WARN_ON(fwspec->param_count < 2))
+		return -EINVAL;
+	*hwirq = fwspec->param[0];
+	*type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
+	return 0;
+}
+
+static const struct irq_domain_ops gpc_irq_domain_ops = {
+	.translate = vf610_gpc_domain_translate,
+	.alloc = vf610_gpc_domain_alloc,
+	.free = irq_domain_free_irqs_common,
+};
+
+static int __init vf610_gpc_of_init(struct device_node *node,
+			       struct device_node *parent)
+{
+	struct irq_domain *domain, *domain_parent;
+	int i;
+
+	domain_parent = irq_find_host(parent);
+	if (!domain_parent) {
+		pr_err("vf610_gpc: interrupt-parent not found\n");
+		return -EINVAL;
+	}
+
+	gpc_base = of_io_request_and_map(node, 0, "gpc");
+	if (WARN_ON(!gpc_base))
+		return PTR_ERR(gpc_base);
+
+	domain = irq_domain_add_hierarchy(domain_parent, 0, VF610_GPC_MAX_IRQS,
+					  node, &gpc_irq_domain_ops, NULL);
+	if (!domain) {
+		iounmap(gpc_base);
+		return -ENOMEM;
+	}
+
+	/* Initially mask all interrupts for wakeup */
+	for (i = 0; i < IMR_NUM; i++)
+		writel_relaxed(~0, gpc_base + VF610_GPC_IMR1 + i * 4);
+
+	return 0;
+}
+IRQCHIP_DECLARE(vf610_gpc, "fsl,vf610-gpc", vf610_gpc_of_init);
-- 
2.7.2