irq-imgpdc: add ImgTec PDC irqchip driver

Add irqchip driver for the ImgTec PowerDown Controller (PDC) as found in
the TZ1090. The PDC has a number of general system wakeup (SysWake)
interrupts (which would for example be connected to a power button or an
external peripheral), and a number of peripheral interrupts which can
also wake the system but are connected straight to specific low-power
peripherals (such as RTC or Infrared). It has a single interrupt output
for SysWakes, and individual interrupt outputs for each peripheral.

The driver demuxes the SysWake interrupt line, and passes the peripheral
interrupts straight through. It also handles the set_wake interrupt
operation to enable/disable the appropriate wake event bits.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Rob Landley <rob@landley.net>
Cc: linux-metag@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: devicetree-discuss@lists.ozlabs.org

3 files changed, 505 insertions, 0 deletions

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 1fea003ed33..3792a1aa52b 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -30,6 +30,11 @@ config ARM_VIC_NR
 	  The maximum number of VICs available in the system, for
 	  power management.
 
+config IMGPDC_IRQ
+	bool
+	select GENERIC_IRQ_CHIP
+	select IRQ_DOMAIN
+
 config ORION_IRQCHIP
 	bool
 	select IRQ_DOMAIN
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index e65c41a7366..81e8cd49ae7 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_ARCH_SPEAR3XX)		+= spear-shirq.o
 obj-$(CONFIG_ARM_GIC)			+= irq-gic.o
 obj-$(CONFIG_ARM_NVIC)			+= irq-nvic.o
 obj-$(CONFIG_ARM_VIC)			+= irq-vic.o
+obj-$(CONFIG_IMGPDC_IRQ)		+= irq-imgpdc.o
 obj-$(CONFIG_SIRF_IRQ)			+= irq-sirfsoc.o
 obj-$(CONFIG_RENESAS_INTC_IRQPIN)	+= irq-renesas-intc-irqpin.o
 obj-$(CONFIG_RENESAS_IRQC)		+= irq-renesas-irqc.o
diff --git a/drivers/irqchip/irq-imgpdc.c b/drivers/irqchip/irq-imgpdc.c
new file mode 100644
index 00000000000..8071c2eb024
--- /dev/null
+++ b/drivers/irqchip/irq-imgpdc.c
@@ -0,0 +1,499 @@
+/*
+ * IMG PowerDown Controller (PDC)
+ *
+ * Copyright 2010-2013 Imagination Technologies Ltd.
+ *
+ * Exposes the syswake and PDC peripheral wake interrupts to the system.
+ *
+ */
+
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
+#include <linux/irqdomain.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+/* PDC interrupt register numbers */
+
+#define PDC_IRQ_STATUS			0x310
+#define PDC_IRQ_ENABLE			0x314
+#define PDC_IRQ_CLEAR			0x318
+#define PDC_IRQ_ROUTE			0x31c
+#define PDC_SYS_WAKE_BASE		0x330
+#define PDC_SYS_WAKE_STRIDE		0x8
+#define PDC_SYS_WAKE_CONFIG_BASE	0x334
+#define PDC_SYS_WAKE_CONFIG_STRIDE	0x8
+
+/* PDC interrupt register field masks */
+
+#define PDC_IRQ_SYS3			0x08
+#define PDC_IRQ_SYS2			0x04
+#define PDC_IRQ_SYS1			0x02
+#define PDC_IRQ_SYS0			0x01
+#define PDC_IRQ_ROUTE_WU_EN_SYS3	0x08000000
+#define PDC_IRQ_ROUTE_WU_EN_SYS2	0x04000000
+#define PDC_IRQ_ROUTE_WU_EN_SYS1	0x02000000
+#define PDC_IRQ_ROUTE_WU_EN_SYS0	0x01000000
+#define PDC_IRQ_ROUTE_WU_EN_WD		0x00040000
+#define PDC_IRQ_ROUTE_WU_EN_IR		0x00020000
+#define PDC_IRQ_ROUTE_WU_EN_RTC		0x00010000
+#define PDC_IRQ_ROUTE_EXT_EN_SYS3	0x00000800
+#define PDC_IRQ_ROUTE_EXT_EN_SYS2	0x00000400
+#define PDC_IRQ_ROUTE_EXT_EN_SYS1	0x00000200
+#define PDC_IRQ_ROUTE_EXT_EN_SYS0	0x00000100
+#define PDC_IRQ_ROUTE_EXT_EN_WD		0x00000004
+#define PDC_IRQ_ROUTE_EXT_EN_IR		0x00000002
+#define PDC_IRQ_ROUTE_EXT_EN_RTC	0x00000001
+#define PDC_SYS_WAKE_RESET		0x00000010
+#define PDC_SYS_WAKE_INT_MODE		0x0000000e
+#define PDC_SYS_WAKE_INT_MODE_SHIFT	1
+#define PDC_SYS_WAKE_PIN_VAL		0x00000001
+
+/* PDC interrupt constants */
+
+#define PDC_SYS_WAKE_INT_LOW		0x0
+#define PDC_SYS_WAKE_INT_HIGH		0x1
+#define PDC_SYS_WAKE_INT_DOWN		0x2
+#define PDC_SYS_WAKE_INT_UP		0x3
+#define PDC_SYS_WAKE_INT_CHANGE		0x6
+#define PDC_SYS_WAKE_INT_NONE		0x4
+
+/**
+ * struct pdc_intc_priv - private pdc interrupt data.
+ * @nr_perips:		Number of peripheral interrupt signals.
+ * @nr_syswakes:	Number of syswake signals.
+ * @perip_irqs:		List of peripheral IRQ numbers handled.
+ * @syswake_irq:	Shared PDC syswake IRQ number.
+ * @domain:		IRQ domain for PDC peripheral and syswake IRQs.
+ * @pdc_base:		Base of PDC registers.
+ * @irq_route:		Cached version of PDC_IRQ_ROUTE register.
+ * @lock:		Lock to protect the PDC syswake registers and the cached
+ *			values of those registers in this struct.
+ */
+struct pdc_intc_priv {
+	unsigned int		nr_perips;
+	unsigned int		nr_syswakes;
+	unsigned int		*perip_irqs;
+	unsigned int		syswake_irq;
+	struct irq_domain	*domain;
+	void __iomem		*pdc_base;
+
+	u32			irq_route;
+	raw_spinlock_t		lock;
+};
+
+static void pdc_write(struct pdc_intc_priv *priv, unsigned int reg_offs,
+		      unsigned int data)
+{
+	iowrite32(data, priv->pdc_base + reg_offs);
+}
+
+static unsigned int pdc_read(struct pdc_intc_priv *priv,
+			     unsigned int reg_offs)
+{
+	return ioread32(priv->pdc_base + reg_offs);
+}
+
+/* Generic IRQ callbacks */
+
+#define SYS0_HWIRQ	8
+
+static unsigned int hwirq_is_syswake(irq_hw_number_t hw)
+{
+	return hw >= SYS0_HWIRQ;
+}
+
+static unsigned int hwirq_to_syswake(irq_hw_number_t hw)
+{
+	return hw - SYS0_HWIRQ;
+}
+
+static irq_hw_number_t syswake_to_hwirq(unsigned int syswake)
+{
+	return SYS0_HWIRQ + syswake;
+}
+
+static struct pdc_intc_priv *irqd_to_priv(struct irq_data *data)
+{
+	return (struct pdc_intc_priv *)data->domain->host_data;
+}
+
+/*
+ * perip_irq_mask() and perip_irq_unmask() use IRQ_ROUTE which also contains
+ * wake bits, therefore we cannot use the generic irqchip mask callbacks as they
+ * cache the mask.
+ */
+
+static void perip_irq_mask(struct irq_data *data)
+{
+	struct pdc_intc_priv *priv = irqd_to_priv(data);
+
+	raw_spin_lock(&priv->lock);
+	priv->irq_route &= ~data->mask;
+	pdc_write(priv, PDC_IRQ_ROUTE, priv->irq_route);
+	raw_spin_unlock(&priv->lock);
+}
+
+static void perip_irq_unmask(struct irq_data *data)
+{
+	struct pdc_intc_priv *priv = irqd_to_priv(data);
+
+	raw_spin_lock(&priv->lock);
+	priv->irq_route |= data->mask;
+	pdc_write(priv, PDC_IRQ_ROUTE, priv->irq_route);
+	raw_spin_unlock(&priv->lock);
+}
+
+static int syswake_irq_set_type(struct irq_data *data, unsigned int flow_type)
+{
+	struct pdc_intc_priv *priv = irqd_to_priv(data);
+	unsigned int syswake = hwirq_to_syswake(data->hwirq);
+	unsigned int irq_mode;
+	unsigned int soc_sys_wake_regoff, soc_sys_wake;
+
+	/* translate to syswake IRQ mode */
+	switch (flow_type) {
+	case IRQ_TYPE_EDGE_BOTH:
+		irq_mode = PDC_SYS_WAKE_INT_CHANGE;
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		irq_mode = PDC_SYS_WAKE_INT_UP;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		irq_mode = PDC_SYS_WAKE_INT_DOWN;
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		irq_mode = PDC_SYS_WAKE_INT_HIGH;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		irq_mode = PDC_SYS_WAKE_INT_LOW;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	raw_spin_lock(&priv->lock);
+
+	/* set the IRQ mode */
+	soc_sys_wake_regoff = PDC_SYS_WAKE_BASE + syswake*PDC_SYS_WAKE_STRIDE;
+	soc_sys_wake = pdc_read(priv, soc_sys_wake_regoff);
+	soc_sys_wake &= ~PDC_SYS_WAKE_INT_MODE;
+	soc_sys_wake |= irq_mode << PDC_SYS_WAKE_INT_MODE_SHIFT;
+	pdc_write(priv, soc_sys_wake_regoff, soc_sys_wake);
+
+	/* and update the handler */
+	irq_setup_alt_chip(data, flow_type);
+
+	raw_spin_unlock(&priv->lock);
+
+	return 0;
+}
+
+/* applies to both peripheral and syswake interrupts */
+static int pdc_irq_set_wake(struct irq_data *data, unsigned int on)
+{
+	struct pdc_intc_priv *priv = irqd_to_priv(data);
+	irq_hw_number_t hw = data->hwirq;
+	unsigned int mask = (1 << 16) << hw;
+	unsigned int dst_irq;
+
+	raw_spin_lock(&priv->lock);
+	if (on)
+		priv->irq_route |= mask;
+	else
+		priv->irq_route &= ~mask;
+	pdc_write(priv, PDC_IRQ_ROUTE, priv->irq_route);
+	raw_spin_unlock(&priv->lock);
+
+	/* control the destination IRQ wakeup too for standby mode */
+	if (hwirq_is_syswake(hw))
+		dst_irq = priv->syswake_irq;
+	else
+		dst_irq = priv->perip_irqs[hw];
+	irq_set_irq_wake(dst_irq, on);
+
+	return 0;
+}
+
+static void pdc_intc_perip_isr(unsigned int irq, struct irq_desc *desc)
+{
+	struct pdc_intc_priv *priv;
+	unsigned int i, irq_no;
+
+	priv = (struct pdc_intc_priv *)irq_desc_get_handler_data(desc);
+
+	/* find the peripheral number */
+	for (i = 0; i < priv->nr_perips; ++i)
+		if (irq == priv->perip_irqs[i])
+			goto found;
+
+	/* should never get here */
+	return;
+found:
+
+	/* pass on the interrupt */
+	irq_no = irq_linear_revmap(priv->domain, i);
+	generic_handle_irq(irq_no);
+}
+
+static void pdc_intc_syswake_isr(unsigned int irq, struct irq_desc *desc)
+{
+	struct pdc_intc_priv *priv;
+	unsigned int syswake, irq_no;
+	unsigned int status;
+
+	priv = (struct pdc_intc_priv *)irq_desc_get_handler_data(desc);
+
+	status = pdc_read(priv, PDC_IRQ_STATUS) &
+		 pdc_read(priv, PDC_IRQ_ENABLE);
+	status &= (1 << priv->nr_syswakes) - 1;
+
+	for (syswake = 0; status; status >>= 1, ++syswake) {
+		/* Has this sys_wake triggered? */
+		if (!(status & 1))
+			continue;
+
+		irq_no = irq_linear_revmap(priv->domain,
+					   syswake_to_hwirq(syswake));
+		generic_handle_irq(irq_no);
+	}
+}
+
+static void pdc_intc_setup(struct pdc_intc_priv *priv)
+{
+	int i;
+	unsigned int soc_sys_wake_regoff;
+	unsigned int soc_sys_wake;
+
+	/*
+	 * Mask all syswake interrupts before routing, or we could receive an
+	 * interrupt before we're ready to handle it.
+	 */
+	pdc_write(priv, PDC_IRQ_ENABLE, 0);
+
+	/*
+	 * Enable routing of all syswakes
+	 * Disable all wake sources
+	 */
+	priv->irq_route = ((PDC_IRQ_ROUTE_EXT_EN_SYS0 << priv->nr_syswakes) -
+				PDC_IRQ_ROUTE_EXT_EN_SYS0);
+	pdc_write(priv, PDC_IRQ_ROUTE, priv->irq_route);
+
+	/* Initialise syswake IRQ */
+	for (i = 0; i < priv->nr_syswakes; ++i) {
+		/* set the IRQ mode to none */
+		soc_sys_wake_regoff = PDC_SYS_WAKE_BASE + i*PDC_SYS_WAKE_STRIDE;
+		soc_sys_wake = PDC_SYS_WAKE_INT_NONE
+				<< PDC_SYS_WAKE_INT_MODE_SHIFT;
+		pdc_write(priv, soc_sys_wake_regoff, soc_sys_wake);
+	}
+}
+
+static int pdc_intc_probe(struct platform_device *pdev)
+{
+	struct pdc_intc_priv *priv;
+	struct device_node *node = pdev->dev.of_node;
+	struct resource *res_regs;
+	struct irq_chip_generic *gc;
+	unsigned int i;
+	int irq, ret;
+	u32 val;
+
+	if (!node)
+		return -ENOENT;
+
+	/* Get registers */
+	res_regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (res_regs == NULL) {
+		dev_err(&pdev->dev, "cannot find registers resource\n");
+		return -ENOENT;
+	}
+
+	/* Allocate driver data */
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv) {
+		dev_err(&pdev->dev, "cannot allocate device data\n");
+		return -ENOMEM;
+	}
+	raw_spin_lock_init(&priv->lock);
+	platform_set_drvdata(pdev, priv);
+
+	/* Ioremap the registers */
+	priv->pdc_base = devm_ioremap(&pdev->dev, res_regs->start,
+				      res_regs->end - res_regs->start);
+	if (!priv->pdc_base)
+		return -EIO;
+
+	/* Get number of peripherals */
+	ret = of_property_read_u32(node, "num-perips", &val);
+	if (ret) {
+		dev_err(&pdev->dev, "No num-perips node property found\n");
+		return -EINVAL;
+	}
+	if (val > SYS0_HWIRQ) {
+		dev_err(&pdev->dev, "num-perips (%u) out of range\n", val);
+		return -EINVAL;
+	}
+	priv->nr_perips = val;
+
+	/* Get number of syswakes */
+	ret = of_property_read_u32(node, "num-syswakes", &val);
+	if (ret) {
+		dev_err(&pdev->dev, "No num-syswakes node property found\n");
+		return -EINVAL;
+	}
+	if (val > SYS0_HWIRQ) {
+		dev_err(&pdev->dev, "num-syswakes (%u) out of range\n", val);
+		return -EINVAL;
+	}
+	priv->nr_syswakes = val;
+
+	/* Get peripheral IRQ numbers */
+	priv->perip_irqs = devm_kzalloc(&pdev->dev, 4 * priv->nr_perips,
+					GFP_KERNEL);
+	if (!priv->perip_irqs) {
+		dev_err(&pdev->dev, "cannot allocate perip IRQ list\n");
+		return -ENOMEM;
+	}
+	for (i = 0; i < priv->nr_perips; ++i) {
+		irq = platform_get_irq(pdev, 1 + i);
+		if (irq < 0) {
+			dev_err(&pdev->dev, "cannot find perip IRQ #%u\n", i);
+			return irq;
+		}
+		priv->perip_irqs[i] = irq;
+	}
+	/* check if too many were provided */
+	if (platform_get_irq(pdev, 1 + i) >= 0) {
+		dev_err(&pdev->dev, "surplus perip IRQs detected\n");
+		return -EINVAL;
+	}
+
+	/* Get syswake IRQ number */
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "cannot find syswake IRQ\n");
+		return irq;
+	}
+	priv->syswake_irq = irq;
+
+	/* Set up an IRQ domain */
+	priv->domain = irq_domain_add_linear(node, 16, &irq_generic_chip_ops,
+					     priv);
+	if (unlikely(!priv->domain)) {
+		dev_err(&pdev->dev, "cannot add IRQ domain\n");
+		return -ENOMEM;
+	}
+
+	/*
+	 * Set up 2 generic irq chips with 2 chip types.
+	 * The first one for peripheral irqs (only 1 chip type used)
+	 * The second one for syswake irqs (edge and level chip types)
+	 */
+	ret = irq_alloc_domain_generic_chips(priv->domain, 8, 2, "pdc",
+					     handle_level_irq, 0, 0,
+					     IRQ_GC_INIT_NESTED_LOCK);
+	if (ret)
+		goto err_generic;
+
+	/* peripheral interrupt chip */
+
+	gc = irq_get_domain_generic_chip(priv->domain, 0);
+	gc->unused	= ~(BIT(priv->nr_perips) - 1);
+	gc->reg_base	= priv->pdc_base;
+	/*
+	 * IRQ_ROUTE contains wake bits, so we can't use the generic versions as
+	 * they cache the mask
+	 */
+	gc->chip_types[0].regs.mask		= PDC_IRQ_ROUTE;
+	gc->chip_types[0].chip.irq_mask		= perip_irq_mask;
+	gc->chip_types[0].chip.irq_unmask	= perip_irq_unmask;
+	gc->chip_types[0].chip.irq_set_wake	= pdc_irq_set_wake;
+
+	/* syswake interrupt chip */
+
+	gc = irq_get_domain_generic_chip(priv->domain, 8);
+	gc->unused	= ~(BIT(priv->nr_syswakes) - 1);
+	gc->reg_base	= priv->pdc_base;
+
+	/* edge interrupts */
+	gc->chip_types[0].type			= IRQ_TYPE_EDGE_BOTH;
+	gc->chip_types[0].handler		= handle_edge_irq;
+	gc->chip_types[0].regs.ack		= PDC_IRQ_CLEAR;
+	gc->chip_types[0].regs.mask		= PDC_IRQ_ENABLE;
+	gc->chip_types[0].chip.irq_ack		= irq_gc_ack_set_bit;
+	gc->chip_types[0].chip.irq_mask		= irq_gc_mask_clr_bit;
+	gc->chip_types[0].chip.irq_unmask	= irq_gc_mask_set_bit;
+	gc->chip_types[0].chip.irq_set_type	= syswake_irq_set_type;
+	gc->chip_types[0].chip.irq_set_wake	= pdc_irq_set_wake;
+	/* for standby we pass on to the shared syswake IRQ */
+	gc->chip_types[0].chip.flags		= IRQCHIP_MASK_ON_SUSPEND;
+
+	/* level interrupts */
+	gc->chip_types[1].type			= IRQ_TYPE_LEVEL_MASK;
+	gc->chip_types[1].handler		= handle_level_irq;
+	gc->chip_types[1].regs.ack		= PDC_IRQ_CLEAR;
+	gc->chip_types[1].regs.mask		= PDC_IRQ_ENABLE;
+	gc->chip_types[1].chip.irq_ack		= irq_gc_ack_set_bit;
+	gc->chip_types[1].chip.irq_mask		= irq_gc_mask_clr_bit;
+	gc->chip_types[1].chip.irq_unmask	= irq_gc_mask_set_bit;
+	gc->chip_types[1].chip.irq_set_type	= syswake_irq_set_type;
+	gc->chip_types[1].chip.irq_set_wake	= pdc_irq_set_wake;
+	/* for standby we pass on to the shared syswake IRQ */
+	gc->chip_types[1].chip.flags		= IRQCHIP_MASK_ON_SUSPEND;
+
+	/* Set up the hardware to enable interrupt routing */
+	pdc_intc_setup(priv);
+
+	/* Setup chained handlers for the peripheral IRQs */
+	for (i = 0; i < priv->nr_perips; ++i) {
+		irq = priv->perip_irqs[i];
+		irq_set_handler_data(irq, priv);
+		irq_set_chained_handler(irq, pdc_intc_perip_isr);
+	}
+
+	/* Setup chained handler for the syswake IRQ */
+	irq_set_handler_data(priv->syswake_irq, priv);
+	irq_set_chained_handler(priv->syswake_irq, pdc_intc_syswake_isr);
+
+	dev_info(&pdev->dev,
+		 "PDC IRQ controller initialised (%u perip IRQs, %u syswake IRQs)\n",
+		 priv->nr_perips,
+		 priv->nr_syswakes);
+
+	return 0;
+err_generic:
+	irq_domain_remove(priv->domain);
+	return ret;
+}
+
+static int pdc_intc_remove(struct platform_device *pdev)
+{
+	struct pdc_intc_priv *priv = platform_get_drvdata(pdev);
+
+	irq_domain_remove(priv->domain);
+	return 0;
+}
+
+static const struct of_device_id pdc_intc_match[] = {
+	{ .compatible = "img,pdc-intc" },
+	{}
+};
+
+static struct platform_driver pdc_intc_driver = {
+	.driver = {
+		.name		= "pdc-intc",
+		.of_match_table	= pdc_intc_match,
+	},
+	.probe = pdc_intc_probe,
+	.remove = pdc_intc_remove,
+};
+
+static int __init pdc_intc_init(void)
+{
+	return platform_driver_register(&pdc_intc_driver);
+}
+core_initcall(pdc_intc_init);