msm: Add QPNP interrupt support

QPNP is a Qualcomm SPMI based implementation that specifies 256
devices per SPMI slave ID, with up to 8 interrupts per device.
This brings the theoretical max interrupt support to 32768 per
bus for this architecture.

This driver implements the standard irq chip interfaces to
support QPNP. The chip driver is informed of Device Tree
configuration through a notifier interface. Once informed of an
interrupt, it will allocate resources on the fly. In order to
support this large logical interrupt range, we require SPARSE_IRQ
to be enabled.

This driver supports Device Tree interrupt specs with a cell size
of three. These are comprised of the the slave ID, peripheral ID
and irq number.

Change-Id: Ic7847bafe6598a84ab3650df7c95bb605aefbe62
Signed-off-by: Michael Bohan <mbohan@codeaurora.org>
diff --git a/drivers/spmi/Kconfig b/drivers/spmi/Kconfig
index 7768eed..6d12c7e 100644
--- a/drivers/spmi/Kconfig
+++ b/drivers/spmi/Kconfig
@@ -25,5 +25,13 @@
 	bool "MSM QPNP"
 	help
 	  Say 'y' here to include support for the Qualcomm QPNP
+
+config MSM_QPNP_INT
+	depends on SPARSE_IRQ
+	depends on ARCH_MSMCOPPER
+	depends on OF_SPMI
+	bool "MSM QPNP INT"
+	help
+	  Say 'y' here to include support for the Qualcomm QPNP interrupt
 	  support. QPNP is a SPMI based PMIC implementation.
 endif
diff --git a/drivers/spmi/Makefile b/drivers/spmi/Makefile
index 659e886..d59a610 100644
--- a/drivers/spmi/Makefile
+++ b/drivers/spmi/Makefile
@@ -4,3 +4,4 @@
 obj-$(CONFIG_SPMI)			+= spmi.o
 obj-$(CONFIG_SPMI_MSM_PMIC_ARB)		+= spmi-pmic-arb.o
 obj-$(CONFIG_MSM_QPNP)                  += qpnp.o
+obj-$(CONFIG_MSM_QPNP_INT)		+= qpnp-int.o
diff --git a/drivers/spmi/qpnp-int.c b/drivers/spmi/qpnp-int.c
new file mode 100644
index 0000000..2998c01
--- /dev/null
+++ b/drivers/spmi/qpnp-int.c
@@ -0,0 +1,510 @@
+/* Copyright (c) 2012, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/interrupt.h>
+#include <linux/spmi.h>
+#include <linux/radix-tree.h>
+#include <linux/slab.h>
+#include <linux/printk.h>
+
+#include <asm/irq.h>
+#include <asm/mach/irq.h>
+#include <mach/qpnp-int.h>
+
+#define QPNPINT_MAX_BUSSES 1
+
+/* 16 slave_ids, 256 per_ids per slave, and 8 ints per per_id */
+#define QPNPINT_NR_IRQS (16 * 256 * 8)
+
+enum qpnpint_regs {
+	QPNPINT_REG_RT_STS		= 0x10,
+	QPNPINT_REG_SET_TYPE		= 0x11,
+	QPNPINT_REG_POLARITY_HIGH	= 0x12,
+	QPNPINT_REG_POLARITY_LOW	= 0x13,
+	QPNPINT_REG_LATCHED_CLR		= 0x14,
+	QPNPINT_REG_EN_SET		= 0x15,
+	QPNPINT_REG_EN_CLR		= 0x16,
+	QPNPINT_REG_LATCHED_STS		= 0x18,
+};
+
+struct q_perip_data {
+	uint8_t type;	    /* bitmap */
+	uint8_t pol_high;   /* bitmap */
+	uint8_t pol_low;    /* bitmap */
+	uint8_t int_en;     /* bitmap */
+	uint8_t use_count;
+};
+
+struct q_irq_data {
+	uint32_t priv_d; /* data to optimize arbiter interactions */
+	struct q_chip_data *chip_d;
+	struct q_perip_data *per_d;
+	uint8_t mask_shift;
+	uint8_t spmi_slave;
+	uint16_t spmi_offset;
+};
+
+struct q_chip_data {
+	int bus_nr;
+	struct irq_domain domain;
+	struct qpnp_local_int cb;
+	struct spmi_controller *spmi_ctrl;
+	struct radix_tree_root per_tree;
+};
+
+static struct q_chip_data chip_data[QPNPINT_MAX_BUSSES] __read_mostly;
+
+/**
+ * qpnpint_encode_hwirq - translate between qpnp_irq_spec and
+ *			  hwirq representation.
+ *
+ * slave_offset = (addr->slave * 256 * 8);
+ * perip_offset = slave_offset + (addr->perip * 8);
+ * return perip_offset + addr->irq;
+ */
+static inline int qpnpint_encode_hwirq(struct qpnp_irq_spec *spec)
+{
+	uint32_t hwirq;
+
+	if (spec->slave > 15 || spec->irq > 7)
+		return -EINVAL;
+
+	hwirq = (spec->slave << 11);
+	hwirq |= (spec->per << 3);
+	hwirq |= spec->irq;
+
+	return hwirq;
+}
+/**
+ * qpnpint_decode_hwirq - translate between hwirq and
+ *			  qpnp_irq_spec representation.
+ */
+static inline int qpnpint_decode_hwirq(unsigned long hwirq,
+					struct qpnp_irq_spec *spec)
+{
+	if (hwirq > 65535)
+		return -EINVAL;
+
+	spec->slave = (hwirq >> 11) & 0xF;
+	spec->per = (hwirq >> 3) & 0xFF;
+	spec->irq = hwirq & 0x7;
+	return 0;
+}
+
+static int qpnpint_spmi_write(struct q_irq_data *irq_d, uint8_t reg,
+			      void *buf, uint32_t len)
+{
+	struct q_chip_data *chip_d = irq_d->chip_d;
+	int rc;
+
+	if (!chip_d->spmi_ctrl)
+		return -ENODEV;
+
+	rc = spmi_ext_register_writel(chip_d->spmi_ctrl, irq_d->spmi_slave,
+				      irq_d->spmi_offset + reg, buf, len);
+	return rc;
+}
+
+static void qpnpint_irq_mask(struct irq_data *d)
+{
+	struct q_irq_data *irq_d = irq_data_get_irq_chip_data(d);
+	struct q_chip_data *chip_d = irq_d->chip_d;
+	struct q_perip_data *per_d = irq_d->per_d;
+	struct qpnp_irq_spec q_spec;
+	int rc;
+
+	pr_debug("hwirq %lu irq: %d\n", d->hwirq, d->irq);
+
+	if (chip_d->cb.mask) {
+		rc = qpnpint_decode_hwirq(d->hwirq, &q_spec);
+		if (rc)
+			pr_err("%s: decode failed on hwirq %lu\n",
+						 __func__, d->hwirq);
+		else
+			chip_d->cb.mask(chip_d->spmi_ctrl, &q_spec,
+								irq_d->priv_d);
+	}
+
+	per_d->int_en &= ~irq_d->mask_shift;
+
+	rc = qpnpint_spmi_write(irq_d, QPNPINT_REG_EN_CLR,
+					(u8 *)&irq_d->mask_shift, 1);
+	if (rc)
+		pr_err("%s: spmi failure on irq %d\n",
+						 __func__, d->irq);
+}
+
+static void qpnpint_irq_mask_ack(struct irq_data *d)
+{
+	struct q_irq_data *irq_d = irq_data_get_irq_chip_data(d);
+	struct q_chip_data *chip_d = irq_d->chip_d;
+	struct q_perip_data *per_d = irq_d->per_d;
+	struct qpnp_irq_spec q_spec;
+	int rc;
+
+	pr_debug("hwirq %lu irq: %d mask: 0x%x\n", d->hwirq, d->irq,
+							irq_d->mask_shift);
+
+	if (chip_d->cb.mask) {
+		rc = qpnpint_decode_hwirq(d->hwirq, &q_spec);
+		if (rc)
+			pr_err("%s: decode failed on hwirq %lu\n",
+						 __func__, d->hwirq);
+		else
+			chip_d->cb.mask(chip_d->spmi_ctrl, &q_spec,
+								irq_d->priv_d);
+	}
+
+	per_d->int_en &= ~irq_d->mask_shift;
+
+	rc = qpnpint_spmi_write(irq_d, QPNPINT_REG_EN_CLR,
+							&irq_d->mask_shift, 1);
+	if (rc)
+		pr_err("%s: spmi failure on irq %d\n",
+						 __func__, d->irq);
+
+	rc = qpnpint_spmi_write(irq_d, QPNPINT_REG_LATCHED_CLR,
+							&irq_d->mask_shift, 1);
+	if (rc)
+		pr_err("%s: spmi failure on irq %d\n",
+						 __func__, d->irq);
+}
+
+static void qpnpint_irq_unmask(struct irq_data *d)
+{
+	struct q_irq_data *irq_d = irq_data_get_irq_chip_data(d);
+	struct q_chip_data *chip_d = irq_d->chip_d;
+	struct q_perip_data *per_d = irq_d->per_d;
+	struct qpnp_irq_spec q_spec;
+	int rc;
+
+	pr_debug("hwirq %lu irq: %d\n", d->hwirq, d->irq);
+
+	if (chip_d->cb.unmask) {
+		rc = qpnpint_decode_hwirq(d->hwirq, &q_spec);
+		if (rc)
+			pr_err("%s: decode failed on hwirq %lu\n",
+						 __func__, d->hwirq);
+		else
+			chip_d->cb.unmask(chip_d->spmi_ctrl, &q_spec,
+								irq_d->priv_d);
+	}
+
+	per_d->int_en |= irq_d->mask_shift;
+	rc = qpnpint_spmi_write(irq_d, QPNPINT_REG_EN_SET,
+					&irq_d->mask_shift, 1);
+	if (rc)
+		pr_err("%s: spmi failure on irq %d\n",
+						 __func__, d->irq);
+}
+
+static int qpnpint_irq_set_type(struct irq_data *d, unsigned int flow_type)
+{
+	struct q_irq_data *irq_d = irq_data_get_irq_chip_data(d);
+	struct q_perip_data *per_d = irq_d->per_d;
+	int rc;
+	u8 buf[3];
+
+	pr_debug("hwirq %lu irq: %d flow: 0x%x\n", d->hwirq,
+							d->irq, flow_type);
+
+	per_d->pol_high &= ~irq_d->mask_shift;
+	per_d->pol_low &= ~irq_d->mask_shift;
+	if (flow_type & (IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)) {
+		per_d->type |= irq_d->mask_shift; /* edge trig */
+		if (flow_type & IRQF_TRIGGER_RISING)
+			per_d->pol_high |= irq_d->mask_shift;
+		if (flow_type & IRQF_TRIGGER_FALLING)
+			per_d->pol_low |= irq_d->mask_shift;
+	} else {
+		if ((flow_type & IRQF_TRIGGER_HIGH) &&
+		    (flow_type & IRQF_TRIGGER_LOW))
+			return -EINVAL;
+		per_d->type &= ~irq_d->mask_shift; /* level trig */
+		if (flow_type & IRQF_TRIGGER_HIGH)
+			per_d->pol_high |= irq_d->mask_shift;
+		else
+			per_d->pol_high &= ~irq_d->mask_shift;
+	}
+
+	buf[0] = per_d->type;
+	buf[1] = per_d->pol_high;
+	buf[2] = per_d->pol_low;
+
+	rc = qpnpint_spmi_write(irq_d, QPNPINT_REG_SET_TYPE, &buf, 3);
+	if (rc)
+		pr_err("%s: spmi failure on irq %d\n",
+						 __func__, d->irq);
+	return rc;
+}
+
+static struct irq_chip qpnpint_chip = {
+	.name		= "qpnp-int",
+	.irq_mask	= qpnpint_irq_mask,
+	.irq_mask_ack	= qpnpint_irq_mask_ack,
+	.irq_unmask	= qpnpint_irq_unmask,
+	.irq_set_type	= qpnpint_irq_set_type,
+};
+
+static int qpnpint_init_irq_data(struct q_chip_data *chip_d,
+				 struct q_irq_data *irq_d,
+				 unsigned long hwirq)
+{
+	struct qpnp_irq_spec q_spec;
+	int rc;
+
+	irq_d->mask_shift = 1 << (hwirq & 0x7);
+	rc = qpnpint_decode_hwirq(hwirq, &q_spec);
+	if (rc < 0)
+		return rc;
+	irq_d->spmi_slave = q_spec.slave;
+	irq_d->spmi_offset = q_spec.per << 8;
+	irq_d->per_d->use_count++;
+	irq_d->chip_d = chip_d;
+
+	if (chip_d->cb.register_priv_data)
+		rc = chip_d->cb.register_priv_data(chip_d->spmi_ctrl, &q_spec,
+							&irq_d->priv_d);
+	return rc;
+}
+
+static struct q_irq_data *qpnpint_alloc_irq_data(
+					struct q_chip_data *chip_d,
+					unsigned long hwirq)
+{
+	struct q_irq_data *irq_d;
+	struct q_perip_data *per_d;
+
+	irq_d = kzalloc(sizeof(struct q_irq_data), GFP_KERNEL);
+	if (!irq_d)
+		return ERR_PTR(-ENOMEM);
+
+	/**
+	 * The Peripheral Tree is keyed from the slave + per_id. We're
+	 * ignoring the irq bits here since this peripheral structure
+	 * should be common for all irqs on the same peripheral.
+	 */
+	per_d = radix_tree_lookup(&chip_d->per_tree, (hwirq & ~0x7));
+	if (!per_d) {
+		per_d = kzalloc(sizeof(struct q_perip_data), GFP_KERNEL);
+		if (!per_d)
+			return ERR_PTR(-ENOMEM);
+		radix_tree_insert(&chip_d->per_tree,
+				  (hwirq & ~0x7), per_d);
+	}
+	irq_d->per_d = per_d;
+
+	return irq_d;
+}
+
+static int qpnpint_register_int(uint32_t busno, unsigned long hwirq)
+{
+	int irq, rc;
+	struct irq_domain *domain;
+	struct q_irq_data *irq_d;
+
+	pr_debug("busno = %u hwirq = %lu\n", busno, hwirq);
+
+	if (hwirq < 0 || hwirq >= 32768) {
+		pr_err("%s: hwirq %lu out of qpnp interrupt bounds\n",
+							__func__, hwirq);
+		return -EINVAL;
+	}
+
+	if (busno < 0 || busno > QPNPINT_MAX_BUSSES) {
+		pr_err("%s: invalid bus number %d\n", __func__, busno);
+		return -EINVAL;
+	}
+
+	domain = &chip_data[busno].domain;
+	irq = irq_domain_to_irq(domain, hwirq);
+
+	rc = irq_alloc_desc_at(irq, numa_node_id());
+	if (rc < 0) {
+		if (rc != -EEXIST)
+			pr_err("%s: failed to alloc irq at %d with "
+					"rc %d\n", __func__, irq, rc);
+		return rc;
+	}
+	irq_d = qpnpint_alloc_irq_data(&chip_data[busno], hwirq);
+	if (IS_ERR(irq_d)) {
+		pr_err("%s: failed to alloc irq data %d with "
+					"rc %d\n", __func__, irq, rc);
+		rc = PTR_ERR(irq_d);
+		goto register_err_cleanup;
+	}
+	rc = qpnpint_init_irq_data(&chip_data[busno], irq_d, hwirq);
+	if (rc) {
+		pr_err("%s: failed to init irq data %d with "
+					"rc %d\n", __func__, irq, rc);
+		goto register_err_cleanup;
+	}
+
+	irq_domain_register_irq(domain, hwirq);
+
+	irq_set_chip_and_handler(irq,
+			&qpnpint_chip,
+			handle_level_irq);
+	irq_set_chip_data(irq, irq_d);
+#ifdef CONFIG_ARM
+	set_irq_flags(irq, IRQF_VALID);
+#else
+	irq_set_noprobe(irq);
+#endif
+	return 0;
+
+register_err_cleanup:
+	irq_free_desc(irq);
+	if (!IS_ERR(irq_d)) {
+		if (irq_d->per_d->use_count == 1)
+			kfree(irq_d->per_d);
+		else
+			irq_d->per_d->use_count--;
+		kfree(irq_d);
+	}
+	return rc;
+}
+
+static int qpnpint_irq_domain_dt_translate(struct irq_domain *d,
+				       struct device_node *controller,
+				       const u32 *intspec, unsigned int intsize,
+				       unsigned long *out_hwirq,
+				       unsigned int *out_type)
+{
+	struct qpnp_irq_spec addr;
+	struct q_chip_data *chip_d = d->priv;
+	int ret;
+
+	pr_debug("%s: intspec[0] 0x%x intspec[1] 0x%x intspec[2] 0x%x\n",
+				__func__, intspec[0], intspec[1], intspec[2]);
+
+	if (d->of_node != controller)
+		return -EINVAL;
+	if (intsize != 3)
+		return -EINVAL;
+
+	addr.irq = intspec[2] & 0x7;
+	addr.per = intspec[1] & 0xFF;
+	addr.slave = intspec[0] & 0xF;
+
+	ret = qpnpint_encode_hwirq(&addr);
+	if (ret < 0) {
+		pr_err("%s: invalid intspec\n", __func__);
+		return ret;
+	}
+	*out_hwirq = ret;
+	*out_type = IRQ_TYPE_NONE;
+
+	/**
+	 * Register the interrupt if it's not already registered.
+	 * This implies that mapping a qpnp interrupt allocates
+	 * resources.
+	 */
+	ret = qpnpint_register_int(chip_d->bus_nr, *out_hwirq);
+	if (ret && ret != -EEXIST) {
+		pr_err("%s: Cannot register hwirq %lu\n", __func__, *out_hwirq);
+		return ret;
+	}
+
+	return 0;
+}
+
+const struct irq_domain_ops qpnpint_irq_domain_ops = {
+	.dt_translate = qpnpint_irq_domain_dt_translate,
+};
+
+int qpnpint_register_controller(unsigned int busno,
+				struct qpnp_local_int *li_cb)
+{
+	if (busno >= QPNPINT_MAX_BUSSES)
+		return -EINVAL;
+	chip_data[busno].cb = *li_cb;
+	chip_data[busno].spmi_ctrl = spmi_busnum_to_ctrl(busno);
+	if (!chip_data[busno].spmi_ctrl)
+		return -ENOENT;
+
+	return 0;
+}
+EXPORT_SYMBOL(qpnpint_register_controller);
+
+int qpnpint_handle_irq(struct spmi_controller *spmi_ctrl,
+		       struct qpnp_irq_spec *spec)
+{
+	struct irq_domain *domain;
+	unsigned long hwirq, busno;
+	int irq;
+
+	pr_debug("spec slave = %u per = %u irq = %u\n",
+					spec->slave, spec->per, spec->irq);
+
+	if (!spec || !spmi_ctrl)
+		return -EINVAL;
+
+	busno = spmi_ctrl->nr;
+	if (busno >= QPNPINT_MAX_BUSSES)
+		return -EINVAL;
+
+	hwirq = qpnpint_encode_hwirq(spec);
+	if (hwirq < 0) {
+		pr_err("%s: invalid irq spec passed\n", __func__);
+		return -EINVAL;
+	}
+
+	domain = &chip_data[busno].domain;
+	irq = irq_domain_to_irq(domain, hwirq);
+
+	generic_handle_irq(irq);
+
+	return 0;
+}
+EXPORT_SYMBOL(qpnpint_handle_irq);
+
+/**
+ * This assumes that there's a relationship between the order of the interrupt
+ * controllers specified to of_irq_match() is the SPMI device topology. If
+ * this ever turns out to be a bad assumption, then of_irq_init_cb_t should
+ * be modified to pass a parameter to this function.
+ */
+static int qpnpint_cnt __initdata;
+
+int __init qpnpint_of_init(struct device_node *node, struct device_node *parent)
+{
+	struct q_chip_data *chip_d = &chip_data[qpnpint_cnt];
+	struct irq_domain *domain = &chip_d->domain;
+
+	INIT_RADIX_TREE(&chip_d->per_tree, GFP_ATOMIC);
+
+	domain->irq_base = irq_domain_find_free_range(0, QPNPINT_NR_IRQS);
+	domain->nr_irq = QPNPINT_NR_IRQS;
+	domain->of_node = of_node_get(node);
+	domain->priv = chip_d;
+	domain->ops = &qpnpint_irq_domain_ops;
+	irq_domain_add(domain);
+
+	pr_info("irq_base = %d\n", domain->irq_base);
+
+	qpnpint_cnt++;
+
+	return 0;
+}
+EXPORT_SYMBOL(qpnpint_of_init);