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    Subject[PATCH 4/4] gpio: qcom-smp2p: Qualcomm Shared Memory Point to Point
    Date
    Introduce the Qualcomm Shard Memory Point to Point driver, exposing bits
    from the SMP2P protocol as gpio and interrupt controllers.

    Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
    ---
    drivers/gpio/Kconfig | 7 +
    drivers/gpio/Makefile | 1 +
    drivers/gpio/gpio-qcom-smp2p.c | 601 +++++++++++++++++++++++++++++++++++++++++
    3 files changed, 609 insertions(+)
    create mode 100644 drivers/gpio/gpio-qcom-smp2p.c

    diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
    index 0e57b60faae8..82c61ce5af8f 100644
    --- a/drivers/gpio/Kconfig
    +++ b/drivers/gpio/Kconfig
    @@ -354,6 +354,13 @@ config GPIO_PXA
    help
    Say yes here to support the PXA GPIO device

    +config GPIO_QCOM_SMP2P
    + bool "Qualcomm Shared Memory Point to Point support"
    + depends on QCOM_SMEM
    + help
    + Say yes here to support the Qualcomm Shared Memory Point to Point
    + protocol, exposed to the system as GPIOs.
    +
    config GPIO_QCOM_SMSM
    bool "Qualcomm Shared Memory State Machine"
    depends on QCOM_SMEM
    diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
    index 0fd213892403..fdab869a7212 100644
    --- a/drivers/gpio/Makefile
    +++ b/drivers/gpio/Makefile
    @@ -75,6 +75,7 @@ obj-$(CONFIG_GPIO_PCF857X) += gpio-pcf857x.o
    obj-$(CONFIG_GPIO_PCH) += gpio-pch.o
    obj-$(CONFIG_GPIO_PL061) += gpio-pl061.o
    obj-$(CONFIG_GPIO_PXA) += gpio-pxa.o
    +obj-$(CONFIG_GPIO_QCOM_SMP2P) += gpio-qcom-smp2p.o
    obj-$(CONFIG_GPIO_QCOM_SMSM) += gpio-qcom-smsm.o
    obj-$(CONFIG_GPIO_RC5T583) += gpio-rc5t583.o
    obj-$(CONFIG_GPIO_RDC321X) += gpio-rdc321x.o
    diff --git a/drivers/gpio/gpio-qcom-smp2p.c b/drivers/gpio/gpio-qcom-smp2p.c
    new file mode 100644
    index 000000000000..f2eb2f095cc0
    --- /dev/null
    +++ b/drivers/gpio/gpio-qcom-smp2p.c
    @@ -0,0 +1,601 @@
    +/*
    + * Copyright (c) 2015, Sony Mobile Communications AB.
    + * Copyright (c) 2012-2013, The Linux Foundation. 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.
    + */
    +
    +#include <linux/gpio.h>
    +#include <linux/interrupt.h>
    +#include <linux/list.h>
    +#include <linux/mfd/syscon.h>
    +#include <linux/module.h>
    +#include <linux/platform_device.h>
    +#include <linux/regmap.h>
    +#include <linux/soc/qcom/smem.h>
    +#include <linux/spinlock.h>
    +
    +/*
    + * The Shared Memory Point to Point (SMP2P) protocol facilitates communication
    + * of a single 32-bit value between two processors. Each value has a single
    + * writer (the local side) and a single reader (the remote side). Values are
    + * uniquely identified in the system by the directed edge (local processor ID
    + * to remote processor ID) and a string identifier.
    + *
    + * Each processor is responsible for creating the outgoing SMEM items and each
    + * item is writable by the local processor and readable by the remote
    + * processor. By using two separate SMEM items that are single-reader and
    + * single-writer, SMP2P does not require any remote locking mechanisms.
    + *
    + * The driver uses the Linux GPIO and interrupt framework to expose a virtual
    + * GPIO for each outbound entry and a virtual interrupt controller for each
    + * inbound entry.
    + */
    +
    +#define SMP2P_MAX_ENTRY 16
    +#define SMP2P_MAX_ENTRY_NAME 16
    +
    +#define SMP2P_FEATURE_SSR_ACK 0x1
    +
    +#define SMP2P_MAGIC 0x504d5324
    +
    +/**
    + * struct smp2p_smem_item - in memory communication structure
    + * @magic: magic number
    + * @version: version - must be 1
    + * @features: features flag - currently unused
    + * @local_pid: processor id of sending end
    + * @remote_pid: processor id of receiving end
    + * @total_entries: number of entries - always SMP2P_MAX_ENTRY
    + * @valid_entries: number of allocated entries
    + * @flags:
    + * @entries: individual communication entries
    + * @name: name of the entry
    + * @value: content of the entry
    + */
    +struct smp2p_smem_item {
    + u32 magic;
    + u8 version;
    + unsigned features:24;
    + u16 local_pid;
    + u16 remote_pid;
    + u16 total_entries;
    + u16 valid_entries;
    + u32 flags;
    +
    + struct {
    + u8 name[SMP2P_MAX_ENTRY_NAME];
    + u32 value;
    + } entries[SMP2P_MAX_ENTRY];
    +} __packed;
    +
    +/**
    + * struct smp2p_entry - driver context matching one entry
    + * @node: list entry to keep track of allocated entries
    + * @smp2p: reference to the device driver context
    + * @name: name of the entry, to match against smp2p_smem_item
    + * @value: pointer to smp2p_smem_item entry value
    + * @last_value: last handled value
    + * @domain: irq_domain for inbound entries
    + * @irq_enabled:bitmap to track enabled irq bits
    + * @irq_rising: bitmap to mark irq bits for rising detection
    + * @irq_falling:bitmap to mark irq bits for falling detection
    + * @chip: gpio_chip for outbound entries
    + * @lock: spinlock to protect read-modify-write of the value
    + */
    +struct smp2p_entry {
    + struct list_head node;
    + struct qcom_smp2p *smp2p;
    +
    + const char *name;
    + u32 *value;
    + u32 last_value;
    +
    + struct irq_domain *domain;
    + DECLARE_BITMAP(irq_enabled, 32);
    + DECLARE_BITMAP(irq_rising, 32);
    + DECLARE_BITMAP(irq_falling, 32);
    +
    + struct gpio_chip chip;
    +
    + spinlock_t lock;
    +};
    +
    +#define SMP2P_INBOUND 0
    +#define SMP2P_OUTBOUND 1
    +
    +/**
    + * struct qcom_smp2p - device driver context
    + * @dev: device driver handle
    + * @in: pointer to the inbound smem item
    + * @smem_items: ids of the two smem items
    + * @valid_entries: already scanned inbound entries
    + * @local_pid: processor id of the inbound edge
    + * @remote_pid: processor id of the outbound edge
    + * @ipc_regmap: regmap for the outbound ipc
    + * @ipc_offset: offset within the regmap
    + * @ipc_bit: bit in regmap@offset to kick to signal remote processor
    + * @inbound: list of inbound entries
    + * @outbound: list of outbound entries
    + */
    +struct qcom_smp2p {
    + struct device *dev;
    +
    + struct smp2p_smem_item *in;
    + struct smp2p_smem_item *out;
    +
    + unsigned smem_items[SMP2P_OUTBOUND + 1];
    +
    + unsigned valid_entries;
    +
    + unsigned local_pid;
    + unsigned remote_pid;
    +
    + struct regmap *ipc_regmap;
    + int ipc_offset;
    + int ipc_bit;
    +
    + struct list_head inbound;
    + struct list_head outbound;
    +};
    +
    +static void qcom_smp2p_kick(struct qcom_smp2p *smp2p)
    +{
    + /* Make sure any updated data is written before the kick */
    + wmb();
    + regmap_write(smp2p->ipc_regmap, smp2p->ipc_offset, BIT(smp2p->ipc_bit));
    +}
    +
    +/**
    + * qcom_smp2p_intr() - interrupt handler for incoming notifications
    + * @irq: unused
    + * @data: smp2p driver context
    + *
    + * Handle notifications from the remote side to handle newly allocated entries
    + * or any changes to the state bits of existing entries.
    + */
    +static irqreturn_t qcom_smp2p_intr(int irq, void *data)
    +{
    + struct smp2p_smem_item *in;
    + struct smp2p_entry *entry;
    + struct qcom_smp2p *smp2p = data;
    + unsigned smem_id = smp2p->smem_items[SMP2P_INBOUND];
    + unsigned pid = smp2p->remote_pid;
    + size_t size;
    + int irq_pin;
    + u32 status;
    + char buf[SMP2P_MAX_ENTRY_NAME];
    + u32 val;
    + int ret;
    + int i;
    +
    + in = smp2p->in;
    +
    + /* Acquire smem item, if not already found */
    + if (!in) {
    + ret = qcom_smem_get(pid, smem_id, (void **)&in, &size);
    + if (ret < 0) {
    + dev_err(smp2p->dev,
    + "Unable to acquire remote smp2p item\n");
    + return IRQ_HANDLED;
    + }
    +
    + smp2p->in = in;
    + }
    +
    + /* Match newly created entries */
    + for (i = smp2p->valid_entries; i < in->valid_entries; i++) {
    + list_for_each_entry(entry, &smp2p->inbound, node) {
    + memcpy_fromio(buf, in->entries[i].name, sizeof(buf));
    + if (!strcmp(buf, entry->name)) {
    + entry->value = &in->entries[i].value;
    + break;
    + }
    + }
    + }
    + smp2p->valid_entries = i;
    +
    + /* Fire interrupts based on any value changes */
    + list_for_each_entry(entry, &smp2p->inbound, node) {
    + /* Ignore entries not yet allocated by the remote side */
    + if (!entry->value)
    + continue;
    +
    + val = readl(entry->value);
    +
    + status = val ^ entry->last_value;
    + entry->last_value = val;
    +
    + /* No changes of this entry? */
    + if (!status)
    + continue;
    +
    + for_each_set_bit(i, entry->irq_enabled, 32) {
    + if (!(status & BIT(i)))
    + continue;
    +
    + if (val & BIT(i)) {
    + if (test_bit(i, entry->irq_rising)) {
    + irq_pin = irq_find_mapping(entry->domain, i);
    + handle_nested_irq(irq_pin);
    + }
    + } else {
    + if (test_bit(i, entry->irq_falling)) {
    + irq_pin = irq_find_mapping(entry->domain, i);
    + handle_nested_irq(irq_pin);
    + }
    + }
    +
    + }
    + }
    +
    + return IRQ_HANDLED;
    +}
    +
    +static void smp2p_mask_irq(struct irq_data *irqd)
    +{
    + struct smp2p_entry *entry = irq_data_get_irq_chip_data(irqd);
    + irq_hw_number_t irq = irqd_to_hwirq(irqd);
    +
    + clear_bit(irq, entry->irq_enabled);
    +}
    +
    +static void smp2p_unmask_irq(struct irq_data *irqd)
    +{
    + struct smp2p_entry *entry = irq_data_get_irq_chip_data(irqd);
    + irq_hw_number_t irq = irqd_to_hwirq(irqd);
    +
    + set_bit(irq, entry->irq_enabled);
    +}
    +
    +static int smp2p_set_irq_type(struct irq_data *irqd, unsigned int type)
    +{
    + struct smp2p_entry *entry = irq_data_get_irq_chip_data(irqd);
    + irq_hw_number_t irq = irqd_to_hwirq(irqd);
    +
    + if (!(type & IRQ_TYPE_EDGE_BOTH))
    + return -EINVAL;
    +
    + if (type & IRQ_TYPE_EDGE_RISING)
    + set_bit(irq, entry->irq_rising);
    + else
    + clear_bit(irq, entry->irq_rising);
    +
    + if (type & IRQ_TYPE_EDGE_FALLING)
    + set_bit(irq, entry->irq_falling);
    + else
    + clear_bit(irq, entry->irq_falling);
    +
    + return 0;
    +}
    +
    +static struct irq_chip smp2p_irq_chip = {
    + .name = "smp2p",
    + .irq_mask = smp2p_mask_irq,
    + .irq_unmask = smp2p_unmask_irq,
    + .irq_set_type = smp2p_set_irq_type,
    +};
    +
    +static int smp2p_irq_map(struct irq_domain *d,
    + unsigned int irq,
    + irq_hw_number_t hw)
    +{
    + struct smp2p_entry *entry = d->host_data;
    +
    + irq_set_chip_and_handler(irq, &smp2p_irq_chip, handle_level_irq);
    + irq_set_chip_data(irq, entry);
    + irq_set_nested_thread(irq, 1);
    + irq_set_noprobe(irq);
    +
    + return 0;
    +}
    +
    +static const struct irq_domain_ops smp2p_irq_ops = {
    + .map = smp2p_irq_map,
    + .xlate = irq_domain_xlate_twocell,
    +};
    +
    +static int smp2p_gpio_direction_output(struct gpio_chip *chip,
    + unsigned offset,
    + int value)
    +{
    + struct smp2p_entry *entry = container_of(chip, struct smp2p_entry, chip);
    + u32 val;
    +
    + spin_lock(&entry->lock);
    + val = readl(entry->value);
    + if (value)
    + val |= BIT(offset);
    + else
    + val &= ~BIT(offset);
    + writel(val, entry->value);
    + spin_unlock(&entry->lock);
    +
    + qcom_smp2p_kick(entry->smp2p);
    +
    + return 0;
    +}
    +
    +static void smp2p_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
    +{
    + smp2p_gpio_direction_output(chip, offset, value);
    +}
    +
    +static const struct gpio_chip smp2p_gpio_chip = {
    + .set = smp2p_gpio_set,
    + .direction_output = smp2p_gpio_direction_output,
    + .owner = THIS_MODULE,
    +};
    +
    +static int qcom_smp2p_inbound_entry(struct qcom_smp2p *smp2p,
    + struct smp2p_entry *entry,
    + struct device_node *node)
    +{
    + entry->domain = irq_domain_add_linear(node, 32, &smp2p_irq_ops, entry);
    + if (!entry->domain) {
    + dev_err(smp2p->dev, "failed to add irq_domain\n");
    + return -ENOMEM;
    + }
    +
    + return 0;
    +}
    +
    +static int qcom_smp2p_outbound_entry(struct qcom_smp2p *smp2p,
    + struct smp2p_entry *entry,
    + struct device_node *node)
    +{
    + struct smp2p_smem_item *out = smp2p->out;
    + char buf[SMP2P_MAX_ENTRY_NAME] = {};
    + int ret;
    +
    + /* Allocate an entry from the smem item */
    + strlcpy(buf, entry->name, SMP2P_MAX_ENTRY_NAME);
    + memcpy_toio(out->entries[out->valid_entries].name, buf, SMP2P_MAX_ENTRY_NAME);
    + out->valid_entries++;
    +
    + /* Make the logical entry reference the physical value */
    + entry->value = &out->entries[out->valid_entries].value;
    +
    + entry->chip = smp2p_gpio_chip;
    + entry->chip.base = -1;
    + entry->chip.ngpio = 32;
    + entry->chip.label = entry->name;
    + entry->chip.dev = smp2p->dev;
    + entry->chip.of_node = node;
    +
    + ret = gpiochip_add(&entry->chip);
    + if (ret)
    + dev_err(smp2p->dev, "failed register gpiochip\n");
    +
    + return 0;
    +}
    +
    +static int qcom_smp2p_alloc_outbound_item(struct qcom_smp2p *smp2p)
    +{
    + struct smp2p_smem_item *out;
    + unsigned smem_id = smp2p->smem_items[SMP2P_OUTBOUND];
    + unsigned pid = smp2p->remote_pid;
    + int ret;
    +
    + ret = qcom_smem_alloc(pid, smem_id, sizeof(*out));
    + if (ret < 0 && ret != -EEXIST) {
    + if (ret != -EPROBE_DEFER)
    + dev_err(smp2p->dev,
    + "unable to allocate local smp2p item\n");
    + return ret;
    + }
    +
    + ret = qcom_smem_get(pid, smem_id, (void **)&out, NULL);
    + if (ret < 0) {
    + dev_err(smp2p->dev, "Unable to acquire local smp2p item\n");
    + return ret;
    + }
    +
    + memset(out, 0, sizeof(*out));
    + out->magic = SMP2P_MAGIC;
    + out->local_pid = smp2p->local_pid;
    + out->remote_pid = smp2p->remote_pid;
    + out->total_entries = SMP2P_MAX_ENTRY;
    + out->valid_entries = 0;
    +
    + /*
    + * Make sure the rest of the header is written before we validate the
    + * item by writing a valid version number.
    + */
    + wmb();
    + out->version = 1;
    +
    + qcom_smp2p_kick(smp2p);
    +
    + smp2p->out = out;
    +
    + return 0;
    +}
    +
    +static int smp2p_parse_ipc(struct qcom_smp2p *smp2p)
    +{
    + struct device_node *syscon;
    + struct device *dev = smp2p->dev;
    + const char *key;
    + int ret;
    +
    + syscon = of_parse_phandle(dev->of_node, "qcom,ipc", 0);
    + if (!syscon) {
    + dev_err(dev, "no qcom,ipc node\n");
    + return -ENODEV;
    + }
    +
    + smp2p->ipc_regmap = syscon_node_to_regmap(syscon);
    + if (IS_ERR(smp2p->ipc_regmap))
    + return PTR_ERR(smp2p->ipc_regmap);
    +
    + key = "qcom,ipc";
    + ret = of_property_read_u32_index(dev->of_node, key, 1, &smp2p->ipc_offset);
    + if (ret < 0) {
    + dev_err(dev, "no offset in %s\n", key);
    + return -EINVAL;
    + }
    +
    + ret = of_property_read_u32_index(dev->of_node, key, 2, &smp2p->ipc_bit);
    + if (ret < 0) {
    + dev_err(dev, "no bit in %s\n", key);
    + return -EINVAL;
    + }
    +
    + return 0;
    +}
    +
    +static int qcom_smp2p_probe(struct platform_device *pdev)
    +{
    + struct smp2p_entry *entry;
    + struct device_node *node;
    + struct qcom_smp2p *smp2p;
    + const char *key;
    + int irq;
    + int ret;
    +
    + smp2p = devm_kzalloc(&pdev->dev, sizeof(*smp2p), GFP_KERNEL);
    + if (!smp2p)
    + return -ENOMEM;
    +
    + smp2p->dev = &pdev->dev;
    + INIT_LIST_HEAD(&smp2p->inbound);
    + INIT_LIST_HEAD(&smp2p->outbound);
    +
    + platform_set_drvdata(pdev, smp2p);
    +
    + ret = smp2p_parse_ipc(smp2p);
    + if (ret)
    + return ret;
    +
    + key = "qcom,smem";
    + ret = of_property_read_u32_array(pdev->dev.of_node, key,
    + smp2p->smem_items, 2);
    + if (ret)
    + return ret;
    +
    + key = "qcom,local-pid";
    + ret = of_property_read_u32(pdev->dev.of_node, key, &smp2p->local_pid);
    + if (ret < 0) {
    + dev_err(&pdev->dev, "failed to read %s\n", key);
    + return -EINVAL;
    + }
    +
    + key = "qcom,remote-pid";
    + ret = of_property_read_u32(pdev->dev.of_node, key, &smp2p->remote_pid);
    + if (ret < 0) {
    + dev_err(&pdev->dev, "failed to read %s\n", key);
    + return -EINVAL;
    + }
    +
    + irq = platform_get_irq(pdev, 0);
    + if (irq < 0) {
    + dev_err(&pdev->dev, "unable to acquire smp2p interrupt\n");
    + return irq;
    + }
    +
    + ret = qcom_smp2p_alloc_outbound_item(smp2p);
    + if (ret < 0)
    + return ret;
    +
    + for_each_available_child_of_node(pdev->dev.of_node, node) {
    + entry = devm_kzalloc(&pdev->dev, sizeof(*entry), GFP_KERNEL);
    + if (!entry) {
    + ret = -ENOMEM;
    + goto unwind_interfaces;
    + }
    +
    + entry->smp2p = smp2p;
    + spin_lock_init(&entry->lock);
    +
    + ret = of_property_read_string(node, "qcom,entry-name", &entry->name);
    + if (ret < 0)
    + goto unwind_interfaces;
    +
    + if (of_property_read_bool(node, "interrupt-controller")) {
    + ret = qcom_smp2p_inbound_entry(smp2p, entry, node);
    + if (ret < 0)
    + goto unwind_interfaces;
    +
    + list_add(&entry->node, &smp2p->inbound);
    + } else if (of_property_read_bool(node, "gpio-controller")) {
    + ret = qcom_smp2p_outbound_entry(smp2p, entry, node);
    + if (ret < 0)
    + goto unwind_interfaces;
    +
    + list_add(&entry->node, &smp2p->outbound);
    + } else {
    + dev_err(&pdev->dev, "neither inbound nor outbound\n");
    + ret = -EINVAL;
    + goto unwind_interfaces;
    + }
    + }
    +
    + /* Kick the outgoing edge after allocating entries */
    + qcom_smp2p_kick(smp2p);
    +
    + ret = devm_request_threaded_irq(&pdev->dev, irq,
    + NULL, qcom_smp2p_intr,
    + IRQF_ONESHOT,
    + "smp2p", (void *)smp2p);
    + if (ret) {
    + dev_err(&pdev->dev, "failed to request interrupt\n");
    + goto unwind_interfaces;
    + }
    +
    +
    + return 0;
    +
    +unwind_interfaces:
    + list_for_each_entry(entry, &smp2p->inbound, node)
    + irq_domain_remove(entry->domain);
    +
    + list_for_each_entry(entry, &smp2p->outbound, node)
    + gpiochip_remove(&entry->chip);
    +
    + smp2p->out->valid_entries = 0;
    +
    + return ret;
    +}
    +
    +static int qcom_smp2p_remove(struct platform_device *pdev)
    +{
    + struct qcom_smp2p *smp2p = platform_get_drvdata(pdev);
    + struct smp2p_entry *entry;
    +
    + list_for_each_entry(entry, &smp2p->inbound, node)
    + irq_domain_remove(entry->domain);
    +
    + list_for_each_entry(entry, &smp2p->outbound, node)
    + gpiochip_remove(&entry->chip);
    +
    + smp2p->out->valid_entries = 0;
    +
    + return 0;
    +}
    +
    +static const struct of_device_id qcom_smp2p_of_match[] = {
    + { .compatible = "qcom,smp2p" },
    + {}
    +};
    +MODULE_DEVICE_TABLE(of, qcom_smp2p_of_match);
    +
    +static struct platform_driver qcom_smp2p_driver = {
    + .probe = qcom_smp2p_probe,
    + .remove = qcom_smp2p_remove,
    + .driver = {
    + .name = "qcom_smp2p",
    + .of_match_table = qcom_smp2p_of_match,
    + },
    +};
    +module_platform_driver(qcom_smp2p_driver);
    +
    +MODULE_DESCRIPTION("Qualcomm Shared Memory Point to Point driver");
    +MODULE_LICENSE("GPL v2");
    --
    1.8.2.2


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