Message-Id: <20211202122122.23548-4-shawn.guo@linaro.org>
Date:   Thu,  2 Dec 2021 20:21:22 +0800
From:   Shawn Guo <shawn.guo@...aro.org>
To:     Marc Zyngier <maz@...nel.org>, Thomas Gleixner <tglx@...utronix.de>
Cc:     Maulik Shah <quic_mkshah@...cinc.com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Loic Poulain <loic.poulain@...aro.org>,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Shawn Guo <shawn.guo@...aro.org>
Subject: [PATCH v3 3/3] irqchip: Add Qualcomm MPM controller driver

Qualcomm SoCs based on the RPM architecture have a MSM Power Manager (MPM)
in always-on domain. In addition to managing resources during sleep, the
hardware also has an interrupt controller that monitors the interrupts
when the system is asleep, wakes up the APSS when one of these interrupts
occur and replays it to GIC after it becomes operational.

It adds an irqchip driver for this interrupt controller, and here are
some notes about it.

- For given SoC, a fixed number of MPM pins are supported, e.g. 96 pins
  on QCM2290.  Each of these MPM pins can be either a MPM_GIC pin or
  a MPM_GPIO pin. The mapping between MPM_GIC pin and GIC interrupt
  is defined by SoC, as well as the mapping between MPM_GPIO pin and
  GPIO number.  The former mapping can be found as the SoC data in this
  MPM driver, while the latter can be found as the msm_gpio_wakeirq_map[]
  in TLMM driver.

- All the register settings are done by APSS on an internal memory
  region called vMPM, and RPM will flush them into hardware after it
  receives a mailbox/IPC notification from APSS.

- When SoC gets awake from sleep mode, the driver will receive an
  interrupt from RPM, so that it can replay interrupt for particular
  polarity.

Signed-off-by: Shawn Guo <shawn.guo@...aro.org>
---
 drivers/irqchip/Kconfig    |   8 +
 drivers/irqchip/Makefile   |   1 +
 drivers/irqchip/qcom-mpm.c | 481 +++++++++++++++++++++++++++++++++++++
 3 files changed, 490 insertions(+)
 create mode 100644 drivers/irqchip/qcom-mpm.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 7038957f4a77..680d2fcf2686 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -430,6 +430,14 @@ config QCOM_PDC
 	  Power Domain Controller driver to manage and configure wakeup
 	  IRQs for Qualcomm Technologies Inc (QTI) mobile chips.
 
+config QCOM_MPM
+	tristate "QCOM MPM"
+	depends on ARCH_QCOM
+	select IRQ_DOMAIN_HIERARCHY
+	help
+	  MSM Power Manager driver to manage and configure wakeup
+	  IRQs for Qualcomm Technologies Inc (QTI) mobile chips.
+
 config CSKY_MPINTC
 	bool
 	depends on CSKY
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index c1f611cbfbf8..0e2e10467e28 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -94,6 +94,7 @@ obj-$(CONFIG_MESON_IRQ_GPIO)		+= irq-meson-gpio.o
 obj-$(CONFIG_GOLDFISH_PIC) 		+= irq-goldfish-pic.o
 obj-$(CONFIG_NDS32)			+= irq-ativic32.o
 obj-$(CONFIG_QCOM_PDC)			+= qcom-pdc.o
+obj-$(CONFIG_QCOM_MPM)			+= qcom-mpm.o
 obj-$(CONFIG_CSKY_MPINTC)		+= irq-csky-mpintc.o
 obj-$(CONFIG_CSKY_APB_INTC)		+= irq-csky-apb-intc.o
 obj-$(CONFIG_RISCV_INTC)		+= irq-riscv-intc.o
diff --git a/drivers/irqchip/qcom-mpm.c b/drivers/irqchip/qcom-mpm.c
new file mode 100644
index 000000000000..4a0dac2e2c6e
--- /dev/null
+++ b/drivers/irqchip/qcom-mpm.c
@@ -0,0 +1,481 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2021, Linaro Limited
+ * Copyright (c) 2010-2020, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/atomic.h>
+#include <linux/cpu_pm.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/irqchip.h>
+#include <linux/irqchip/arm-gic-v3.h>
+#include <linux/irqdomain.h>
+#include <linux/mailbox_client.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/soc/qcom/irq.h>
+#include <linux/spinlock.h>
+
+/*
+ * vMPM register layout:
+ *
+ *    31                              0
+ *    +--------------------------------+
+ *    |            TIMER0              | 0x00
+ *    +--------------------------------+
+ *    |            TIMER1              | 0x04
+ *    +--------------------------------+
+ *    |            ENABLE0             | 0x08
+ *    +--------------------------------+
+ *    |              ...               | ...
+ *    +--------------------------------+
+ *    |            ENABLEn             |
+ *    +--------------------------------+
+ *    |          FALLING_EDGE0         |
+ *    +--------------------------------+
+ *    |              ...               |
+ *    +--------------------------------+
+ *    |            STATUSn             |
+ *    +--------------------------------+
+ *
+ * n = DIV_ROUND_UP(pin_num, 32)
+ *
+ */
+#define MPM_REG_ENABLE		0
+#define MPM_REG_FALLING_EDGE	1
+#define MPM_REG_RISING_EDGE	2
+#define MPM_REG_POLARITY	3
+#define MPM_REG_STATUS		4
+
+#define MPM_NO_PARENT_IRQ	~0UL
+
+/* MPM pin and its GIC hwirq */
+struct mpm_pin {
+	int pin;
+	irq_hw_number_t hwirq;
+};
+
+struct mpm_data {
+	unsigned int pin_num;
+	const struct mpm_pin *gic_pins;
+};
+
+struct qcom_mpm_priv {
+	void __iomem *base;
+	raw_spinlock_t lock;
+	struct mbox_client mbox_client;
+	struct mbox_chan *mbox_chan;
+	const struct mpm_data *data;
+	unsigned int reg_stride;
+	struct irq_domain *domain;
+	struct notifier_block pm_nb;
+	atomic_t cpus_in_pm;
+};
+
+static inline u32
+qcom_mpm_read(struct qcom_mpm_priv *priv, unsigned int reg, unsigned int index)
+{
+	unsigned int offset = (reg * priv->reg_stride + index + 2) * 4;
+
+	return readl_relaxed(priv->base + offset);
+}
+
+static inline void
+qcom_mpm_write(struct qcom_mpm_priv *priv, unsigned int reg,
+	       unsigned int index, u32 val)
+{
+	unsigned int offset = (reg * priv->reg_stride + index + 2) * 4;
+
+	writel_relaxed(val, priv->base + offset);
+
+	/* Ensure the write is completed */
+	wmb();
+}
+
+static inline void qcom_mpm_enable_irq(struct irq_data *d, bool en)
+{
+	struct qcom_mpm_priv *priv = d->chip_data;
+	int pin = d->hwirq;
+	unsigned int index = pin / 32;
+	unsigned int shift = pin % 32;
+	u32 val;
+
+	raw_spin_lock(&priv->lock);
+
+	val = qcom_mpm_read(priv, MPM_REG_ENABLE, index);
+	if (en)
+		val |= BIT(shift);
+	else
+		val &= ~BIT(shift);
+	qcom_mpm_write(priv, MPM_REG_ENABLE, index, val);
+
+	raw_spin_unlock(&priv->lock);
+}
+
+static void qcom_mpm_mask(struct irq_data *d)
+{
+	qcom_mpm_enable_irq(d, false);
+
+	if (d->parent_data)
+		irq_chip_mask_parent(d);
+}
+
+static void qcom_mpm_unmask(struct irq_data *d)
+{
+	qcom_mpm_enable_irq(d, true);
+
+	if (d->parent_data)
+		irq_chip_unmask_parent(d);
+}
+
+static inline void
+mpm_set_type(struct qcom_mpm_priv *priv, bool set, unsigned int reg,
+	     unsigned int index, unsigned int shift)
+{
+	u32 val;
+
+	raw_spin_lock(&priv->lock);
+
+	val = qcom_mpm_read(priv, reg, index);
+	if (set)
+		val |= BIT(shift);
+	else
+		val &= ~BIT(shift);
+	qcom_mpm_write(priv, reg, index, val);
+
+	raw_spin_unlock(&priv->lock);
+}
+
+static int qcom_mpm_set_type(struct irq_data *d, unsigned int type)
+{
+	struct qcom_mpm_priv *priv = d->chip_data;
+	int pin = d->hwirq;
+	unsigned int index = pin / 32;
+	unsigned int shift = pin % 32;
+
+	switch (type & IRQ_TYPE_SENSE_MASK) {
+	case IRQ_TYPE_EDGE_RISING:
+		mpm_set_type(priv, !!(type & IRQ_TYPE_EDGE_RISING),
+			     MPM_REG_RISING_EDGE, index, shift);
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		mpm_set_type(priv, !!(type & IRQ_TYPE_EDGE_FALLING),
+			     MPM_REG_FALLING_EDGE, index, shift);
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		mpm_set_type(priv, !!(type & IRQ_TYPE_LEVEL_HIGH),
+			     MPM_REG_POLARITY, index, shift);
+		break;
+	}
+
+	if (!d->parent_data)
+		return 0;
+
+	if (type & IRQ_TYPE_EDGE_BOTH)
+		type = IRQ_TYPE_EDGE_RISING;
+
+	if (type & IRQ_TYPE_LEVEL_MASK)
+		type = IRQ_TYPE_LEVEL_HIGH;
+
+	return irq_chip_set_type_parent(d, type);
+}
+
+static struct irq_chip qcom_mpm_chip = {
+	.name			= "mpm",
+	.irq_eoi		= irq_chip_eoi_parent,
+	.irq_mask		= qcom_mpm_mask,
+	.irq_unmask		= qcom_mpm_unmask,
+	.irq_retrigger		= irq_chip_retrigger_hierarchy,
+	.irq_set_type		= qcom_mpm_set_type,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+	.flags			= IRQCHIP_MASK_ON_SUSPEND |
+				  IRQCHIP_SKIP_SET_WAKE,
+};
+
+static irq_hw_number_t get_parent_hwirq(struct qcom_mpm_priv *priv, int pin)
+{
+	const struct mpm_pin *gic_pins = priv->data->gic_pins;
+	int i;
+
+	for (i = 0; gic_pins[i].pin >= 0; i++) {
+		int p = gic_pins[i].pin;
+
+		if (p < 0)
+			break;
+
+		if (p == pin)
+			return gic_pins[i].hwirq;
+	}
+
+	return MPM_NO_PARENT_IRQ;
+}
+
+static int qcom_mpm_alloc(struct irq_domain *domain, unsigned int virq,
+			  unsigned int nr_irqs, void *data)
+{
+	struct qcom_mpm_priv *priv = domain->host_data;
+	struct irq_fwspec *fwspec = data;
+	struct irq_fwspec parent_fwspec;
+	irq_hw_number_t parent_hwirq;
+	irq_hw_number_t hwirq;
+	unsigned int type;
+	int  ret;
+
+	ret = irq_domain_translate_twocell(domain, fwspec, &hwirq, &type);
+	if (ret)
+		return ret;
+
+	ret = irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
+					    &qcom_mpm_chip, priv);
+	if (ret)
+		return ret;
+
+	parent_hwirq = get_parent_hwirq(priv, hwirq);
+	if (parent_hwirq == MPM_NO_PARENT_IRQ)
+		return irq_domain_disconnect_hierarchy(domain->parent, virq);
+
+	if (type & IRQ_TYPE_EDGE_BOTH)
+		type = IRQ_TYPE_EDGE_RISING;
+
+	if (type & IRQ_TYPE_LEVEL_MASK)
+		type = IRQ_TYPE_LEVEL_HIGH;
+
+	parent_fwspec.fwnode = domain->parent->fwnode;
+	parent_fwspec.param_count = 3;
+	parent_fwspec.param[0] = 0;
+	parent_fwspec.param[1] = parent_hwirq;
+	parent_fwspec.param[2] = type;
+
+	return irq_domain_alloc_irqs_parent(domain, virq, nr_irqs,
+					    &parent_fwspec);
+}
+
+static const struct irq_domain_ops qcom_mpm_ops = {
+	.alloc		= qcom_mpm_alloc,
+	.free		= irq_domain_free_irqs_common,
+	.translate	= irq_domain_translate_twocell,
+};
+
+/* Triggered by RPM when system resumes from deep sleep */
+static irqreturn_t qcom_mpm_handler(int irq, void *dev_id)
+{
+	struct qcom_mpm_priv *priv = dev_id;
+	unsigned long enable, pending;
+	int i, j;
+
+	for (i = 0; i < priv->reg_stride; i++) {
+		enable = qcom_mpm_read(priv, MPM_REG_ENABLE, i);
+		pending = qcom_mpm_read(priv, MPM_REG_STATUS, i);
+		pending &= enable;
+
+		for_each_set_bit(j, &pending, 32) {
+			unsigned int pin = 32 * i + j;
+			struct irq_desc *desc =
+					irq_resolve_mapping(priv->domain, pin);
+			struct irq_data *d = &desc->irq_data;
+
+			if (!irqd_is_level_type(d))
+				irq_set_irqchip_state(d->irq,
+						IRQCHIP_STATE_PENDING, true);
+
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int qcom_mpm_enter_sleep(struct qcom_mpm_priv *priv)
+{
+	int i, ret;
+
+	for (i = 0; i < priv->reg_stride; i++)
+		qcom_mpm_write(priv, MPM_REG_STATUS, i, 0);
+
+	/* Notify RPM to write vMPM into HW */
+	ret = mbox_send_message(priv->mbox_chan, NULL);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int qcom_mpm_cpu_pm_callback(struct notifier_block *nb,
+				    unsigned long action, void *data)
+{
+	struct qcom_mpm_priv *priv = container_of(nb, struct qcom_mpm_priv,
+						  pm_nb);
+	int ret = NOTIFY_OK;
+	int cpus_in_pm;
+
+	switch (action) {
+	case CPU_PM_ENTER:
+		cpus_in_pm = atomic_inc_return(&priv->cpus_in_pm);
+		/*
+		 * NOTE: comments for num_online_cpus() point out that it's
+		 * only a snapshot so we need to be careful. It should be OK
+		 * for us to use, though.  It's important for us not to miss
+		 * if we're the last CPU going down so it would only be a
+		 * problem if a CPU went offline right after we did the check
+		 * AND that CPU was not idle AND that CPU was the last non-idle
+		 * CPU. That can't happen. CPUs would have to come out of idle
+		 * before the CPU could go offline.
+		 */
+		if (cpus_in_pm < num_online_cpus())
+			return NOTIFY_OK;
+		break;
+	case CPU_PM_ENTER_FAILED:
+	case CPU_PM_EXIT:
+		atomic_dec(&priv->cpus_in_pm);
+		return NOTIFY_OK;
+	default:
+		return NOTIFY_DONE;
+	}
+
+	/*
+	 * It's likely we're on the last CPU. Grab the lock and write MPM for
+	 * sleep. Grabbing the lock means that if we race with another CPU
+	 * coming up we are still guaranteed to be safe.
+	 */
+	if (raw_spin_trylock(&priv->lock)) {
+		if (qcom_mpm_enter_sleep(priv))
+			ret = NOTIFY_BAD;
+		raw_spin_unlock(&priv->lock);
+	} else {
+		/* Another CPU must be up */
+		return NOTIFY_OK;
+	}
+
+	if (ret == NOTIFY_BAD) {
+		/* Double-check if we're here because someone else is up */
+		if (cpus_in_pm < num_online_cpus())
+			ret = NOTIFY_OK;
+		else
+			/* We won't be called w/ CPU_PM_ENTER_FAILED */
+			atomic_dec(&priv->cpus_in_pm);
+	}
+
+	return ret;
+}
+
+static int qcom_mpm_init(struct platform_device *pdev,
+			 struct device_node *parent,
+			 const struct mpm_data *data)
+{
+	struct irq_domain *parent_domain;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct qcom_mpm_priv *priv;
+	unsigned int pin_num;
+	int irq;
+	int ret;
+
+	if (!data)
+		return -ENODEV;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->data = data;
+	pin_num = priv->data->pin_num;
+	priv->reg_stride = DIV_ROUND_UP(pin_num, 32);
+
+	raw_spin_lock_init(&priv->lock);
+
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
+	if (!priv->base)
+		return PTR_ERR(priv->base);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	priv->mbox_client.dev = dev;
+	priv->mbox_chan = mbox_request_channel(&priv->mbox_client, 0);
+	if (IS_ERR(priv->mbox_chan)) {
+		ret = PTR_ERR(priv->mbox_chan);
+		dev_err(dev, "failed to acquire IPC channel: %d\n", ret);
+		return ret;
+	}
+
+	parent_domain = irq_find_host(parent);
+	if (!parent_domain) {
+		dev_err(dev, "failed to find MPM parent domain\n");
+		ret = -ENXIO;
+		goto free_mbox;
+	}
+
+	priv->domain = irq_domain_create_hierarchy(parent_domain,
+				IRQ_DOMAIN_FLAG_QCOM_MPM_WAKEUP, pin_num,
+				of_node_to_fwnode(np), &qcom_mpm_ops, priv);
+	if (!priv->domain) {
+		dev_err(dev, "failed to create MPM domain\n");
+		ret = -ENOMEM;
+		goto free_mbox;
+	}
+
+	irq_domain_update_bus_token(priv->domain, DOMAIN_BUS_WAKEUP);
+
+	ret = devm_request_irq(dev, irq, qcom_mpm_handler,
+			       IRQF_TRIGGER_RISING | IRQF_NO_SUSPEND,
+			       "qcom_mpm", priv);
+	if (ret) {
+		dev_err(dev, "failed to request irq: %d\n", ret);
+		goto remove_domain;
+	}
+
+	priv->pm_nb.notifier_call = qcom_mpm_cpu_pm_callback;
+	cpu_pm_register_notifier(&priv->pm_nb);
+
+	dev_set_drvdata(dev, priv);
+
+	return 0;
+
+remove_domain:
+	irq_domain_remove(priv->domain);
+free_mbox:
+	mbox_free_channel(priv->mbox_chan);
+	return ret;
+}
+
+/*
+ * The mapping between MPM_GIC pin and GIC SPI number on QCM2290.  It's taken
+ * from downstream qcom-mpm-scuba.c with a little transform on the GIC
+ * SPI numbers (the second column).  Due to the binding difference from
+ * the downstream, where GIC SPI numbering starts from 32, we expect the
+ * numbering starts from 0 here, and that's why we have the number minus 32
+ * comparing to the downstream.
+ */
+const struct mpm_pin qcm2290_gic_pins[] = {
+	{ 2, 275 },	/* tsens0_tsens_upper_lower_int */
+	{ 5, 296 },	/* lpass_irq_out_sdc */
+	{ 12, 422 },	/* b3_lfps_rxterm_irq */
+	{ 24, 79 },	/* bi_px_lpi_1_aoss_mx */
+	{ 86, 183 },	/* mpm_wake,spmi_m */
+	{ 90, 260 },	/* eud_p0_dpse_int_mx */
+	{ 91, 260 },	/* eud_p0_dmse_int_mx */
+	{ -1 },
+};
+
+const struct mpm_data qcm2290_data = {
+	.pin_num = 96,
+	.gic_pins = qcm2290_gic_pins,
+};
+
+static int qcm2290_mpm_init(struct platform_device *pdev,
+			    struct device_node *parent)
+{
+	return qcom_mpm_init(pdev, parent, &qcm2290_data);
+}
+
+IRQCHIP_PLATFORM_DRIVER_BEGIN(qcom_mpm)
+IRQCHIP_MATCH("qcom,qcm2290-mpm", qcm2290_mpm_init)
+IRQCHIP_PLATFORM_DRIVER_END(qcom_mpm)
+MODULE_DESCRIPTION("Qualcomm Technologies, Inc. MSM Power Manager");
+MODULE_LICENSE("GPL v2");
-- 
2.17.1

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