This driver exposed the Qualcomm Shared Memory State Machine bits as
GPIOs to the system.
Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxx>
---
drivers/gpio/gpio-qcom-smsm.c | 631 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 631 insertions(+)
create mode 100644 drivers/gpio/gpio-qcom-smsm.c
diff --git a/drivers/gpio/gpio-qcom-smsm.c b/drivers/gpio/gpio-qcom-smsm.c
new file mode 100644
index 000000000000..4b3f28c469b6
--- /dev/null
+++ b/drivers/gpio/gpio-qcom-smsm.c
@@ -0,0 +1,631 @@
+/*
+ * Copyright (c) 2015, Sony Mobile Communications Inc.
+ * 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/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/soc/qcom/smem.h>
+
+/*
+ * This driver implements the Qualcomm Shared Memory State Machine, a mechanism
+ * for communicating single bit state information to remote processors.
+ *
+ * The implementation is based on two sections of shared memory; the first
+ * holding the state bits and the second holding a matrix of subscription bits.
+ *
+ * The state bits are structured in entries of 32 bits, each belonging to one
+ * system in the SoC. The entry belonging to the local system is considered
+ * read-write, while the rest should be considered read-only.
+ *
+ * The subscription matrix consists of N bitmaps per entry, denoting interest
+ * in updates of the entry for each of the N hosts. Upon updating a state bit
+ * each host's subscription bitmap should be queried and the remote system
+ * should be interrupted if they request so.
+ *
+ * The subscription matrix is laid out in entry-major order:
+ * entry0: [host0 ... hostN]
+ * .
+ * .
+ * entryM: [host0 ... hostN]
+ *
+ * A third, optional, shared memory region might contain information regarding
+ * the number of entries in the state bitmap as well as number of columns in
+ * the subscription matrix.
+ */
+
+/*
+ * Shared memory identifiers, used to acquire handles to respective memory
+ * region.
+ */
+#define SMEM_SMSM_SHARED_STATE 85
+#define SMEM_SMSM_CPU_INTR_MASK 333
+#define SMEM_SMSM_SIZE_INFO 419
+
+/*
+ * Default sizes, in case SMEM_SMSM_SIZE_INFO is not found.
+ */
+#define SMSM_DEFAULT_NUM_ENTRIES 8
+#define SMSM_DEFAULT_NUM_HOSTS 3
+
+struct smsm_entry;
+struct smsm_host;
+
+/**
+ * struct qcom_smsm - smsm driver context
+ * @dev: smsm device pointer
+ * @local_host: column in the subscription matrix representing this system
+ * @num_hosts: number of columns in the subscription matrix
+ * @num_entries: number of entries in the state map and rows in the subscription
+ * matrix
+ * @local_state: pointer to the local processor's state bits
+ * @subscription: pointer to local processor's row in subscription matrix
+ * @chip: gpio_chip for interfacing the state bits
+ * @entries: context for each of the entries
+ * @hosts: context for each of the hosts
+ */
+struct qcom_smsm {
+ struct device *dev;
+
+ u32 local_host;
+
+ u32 num_hosts;
+ u32 num_entries;
+
+ u32 *local_state;
+ u32 *subscription;
+ struct gpio_chip chip;
+
+ struct smsm_entry *entries;
+ struct smsm_host *hosts;
+};
+
+/**
+ * struct smsm_entry - per remote processor entry context
+ * @smsm: back-reference to driver context
+ * @domain: IRQ domain for this entry, if representing a remote system
+ * @irq_enabled: bitmap of which state bits IRQs are enabled
+ * @irq_rising: bitmap tracking if rising bits should be propagated
+ * @irq_falling: bitmap tracking if falling bits should be propagated
+ * @last_value: snapshot of state bits last time the interrupts where propagated
+ * @remote_state: pointer to this entry's state bits
+ * @subscription: pointer to a row in the subscription matrix representing this
+ * entry
+ */
+struct smsm_entry {
+ struct qcom_smsm *smsm;
+
+ struct irq_domain *domain;
+ DECLARE_BITMAP(irq_enabled, 32);
+ DECLARE_BITMAP(irq_rising, 32);
+ DECLARE_BITMAP(irq_falling, 32);
+ u32 last_value;
+
+ u32 *remote_state;
+ u32 *subscription;
+};
+
+/**
+ * struct smsm_host - representation of a remote host
+ * @ipc_regmap: regmap for outgoing interrupt
+ * @ipc_offset: offset in @ipc_regmap for outgoing interrupt
+ * @ipc_bit: bit in @ipc_regmap + @ipc_offset for outgoing interrupt
+ */
+struct smsm_host {
+ struct regmap *ipc_regmap;
+ int ipc_offset;
+ int ipc_bit;
+};
+
+/**
+ * smsm_gpio_output() - change bit in outgoing entry and inform subscribers
+ * @chip: gpio_chip for the entry
+ * @offset: bit in the entry
+ * @value: new value
+ *
+ * Used to set and clear the bits in the outgoing/local entry and inform
+ * subscribers about the change.
+ */
+static int smsm_gpio_output(struct gpio_chip *chip, unsigned offset, int value)
+{
+ struct qcom_smsm *smsm = container_of(chip, struct qcom_smsm, chip);
+ struct smsm_host *hostp;
+ u32 host;
+ u32 orig;
+ u32 val;
+
+ /* Update the entry */
+ val = orig = readl(smsm->local_state);
+ if (value)
+ val |= BIT(offset);
+ else
+ val &= ~BIT(offset);
+
+ /* Don't signal if we didn't change the value */
+ if (val == orig)
+ goto done;
+
+ /* Write out the new value */
+ writel(val, smsm->local_state);
+
+ /* Make sure the value update is ordered before any kicks */
+ wmb();
+
+ /* Iterate over all hosts to check whom wants a kick */
+ for (host = 0; host < smsm->num_hosts; host++) {
+ hostp = &smsm->hosts[host];
+
+ val = readl(smsm->subscription + host);
+ if (val & BIT(offset) && hostp->ipc_regmap) {
+ regmap_write(hostp->ipc_regmap,
+ hostp->ipc_offset,
+ BIT(hostp->ipc_bit));
+ }
+ }
+
+done:
+ return 0;
+}
+
+static void smsm_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+ smsm_gpio_output(chip, offset, value);
+}
+
+static const struct gpio_chip smsm_gpio_chip = {
+ .direction_output = smsm_gpio_output,
+ .set = smsm_gpio_set,
+ .owner = THIS_MODULE,
+};
+
+/**
+ * smsm_intr() - cascading IRQ handler for SMSM
+ * @irq: unused
+ * @data: entry related to this IRQ
+ *
+ * This function cascades an incoming interrupt from a remote system, based on
+ * the state bits and configuration.
+ */
+static irqreturn_t smsm_intr(int irq, void *data)
+{
+ struct smsm_entry *entry = data;
+ unsigned i;
+ int irq_pin;
+ u32 changed;
+ u32 val;
+
+ val = readl(entry->remote_state);
+ changed = val ^ entry->last_value;
+ entry->last_value = val;
+
+ for_each_set_bit(i, entry->irq_enabled, 32) {
+ if (!(changed & 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;
+}
+
+/**
+ * smsm_mask_irq() - un-subscribe from cascades of IRQs of a certain staus bit
+ * @irqd: IRQ handle to be masked
+ *
+ * This un-subscribes the local CPU from interrupts upon changes to the defines
+ * status bit. The bit is also cleared from cascading.
+ */
+static void smsm_mask_irq(struct irq_data *irqd)
+{
+ struct smsm_entry *entry = irq_data_get_irq_chip_data(irqd);
+ irq_hw_number_t irq = irqd_to_hwirq(irqd);
+ struct qcom_smsm *smsm = entry->smsm;
+ u32 val;
+
+ if (entry->subscription) {
+ val = readl(entry->subscription + smsm->local_host);
+ val &= ~BIT(irq);
+ writel(val, entry->subscription + smsm->local_host);
+ }
+
+ clear_bit(irq, entry->irq_enabled);
+}
+
+/**
+ * smsm_unmask_irq() - subscribe to cascades of IRQs of a certain status bit
+ * @irqd: IRQ handle to be unmasked
+ *
+
+ * This subscribes the local CPU to interrupts upon changes to the defined
+ * status bit. The bit is also marked for cascading.
+
+ */
+static void smsm_unmask_irq(struct irq_data *irqd)
+{
+ struct smsm_entry *entry = irq_data_get_irq_chip_data(irqd);
+ irq_hw_number_t irq = irqd_to_hwirq(irqd);
+ struct qcom_smsm *smsm = entry->smsm;
+ u32 val;
+
+ set_bit(irq, entry->irq_enabled);
+
+ if (entry->subscription) {
+ val = readl(entry->subscription + smsm->local_host);
+ val |= BIT(irq);
+ writel(val, entry->subscription + smsm->local_host);
+ }
+}
+
+/**
+ * smsm_set_irq_type() - updates the requested IRQ type for the cascading
+ * @irqd: consumer interrupt handle
+ * @type: requested flags
+ */
+static int smsm_set_irq_type(struct irq_data *irqd, unsigned int type)
+{
+ struct smsm_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 smsm_irq_chip = {
+ .name = "smsm",
+ .irq_mask = smsm_mask_irq,
+ .irq_unmask = smsm_unmask_irq,
+ .irq_set_type = smsm_set_irq_type,
+};
+
+/**
+ * smsm_irq_map() - sets up a mapping for a cascaded IRQ
+ * @d: IRQ domain representing an entry
+ * @irq: IRQ to set up
+ * @hw: unused
+ */
+static int smsm_irq_map(struct irq_domain *d,
+ unsigned int irq,
+ irq_hw_number_t hw)
+{
+ struct smsm_entry *entry = d->host_data;
+
+ irq_set_chip_and_handler(irq, &smsm_irq_chip, handle_level_irq);
+ irq_set_chip_data(irq, entry);
+ irq_set_nested_thread(irq, 1);
+
+ return 0;
+}
+
+static const struct irq_domain_ops smsm_irq_ops = {
+ .map = smsm_irq_map,
+ .xlate = irq_domain_xlate_twocell,
+};
+
+/**
+ * smsm_parse_ipc() - parses a qcom,ipc-%d device tree property
+ * @smsm: smsm driver context
+ * @host_id: index of the remote host to be resolved
+ *
+ * Parses device tree to acquire the information needed for sending the
+ * outgoing interrupts to a remote host - identified by @host_id.
+ */
+static int smsm_parse_ipc(struct qcom_smsm *smsm, unsigned host_id)
+{
+ struct device_node *syscon;
+ struct device_node *node = smsm->dev->of_node;
+ struct smsm_host *host = &smsm->hosts[host_id];
+ char key[16];
+ int ret;
+
+ snprintf(key, sizeof(key), "qcom,ipc-%d", host_id);
+ syscon = of_parse_phandle(node, key, 0);
+ if (!syscon)
+ return 0;
+
+ host->ipc_regmap = syscon_node_to_regmap(syscon);
+ if (IS_ERR(host->ipc_regmap))
+ return PTR_ERR(host->ipc_regmap);
+
+ ret = of_property_read_u32_index(node, key, 1, &host->ipc_offset);
+ if (ret < 0) {
+ dev_err(smsm->dev, "no offset in %s\n", key);
+ return -EINVAL;
+ }
+
+ ret = of_property_read_u32_index(node, key, 2, &host->ipc_bit);
+ if (ret < 0) {
+ dev_err(smsm->dev, "no bit in %s\n", key);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/**
+ * smsm_inbound_entry() - parse DT and set up an entry representing a remote system
+ * @smsm: smsm driver context
+ * @entry: entry context to be set up
+ * @node: dt node containing the entry's properties
+ */
+static int smsm_inbound_entry(struct qcom_smsm *smsm,
+ struct smsm_entry *entry,
+ struct device_node *node)
+{
+ int ret;
+ int irq;
+
+ irq = irq_of_parse_and_map(node, 0);
+ if (!irq) {
+ dev_err(smsm->dev, "failed to parse smsm interrupt\n");
+ return -EINVAL;
+ }
+
+ ret = devm_request_threaded_irq(smsm->dev, irq,
+ NULL, smsm_intr,
+ IRQF_ONESHOT,
+ "smsm", (void *)entry);
+ if (ret) {
+ dev_err(smsm->dev, "failed to request interrupt\n");
+ return ret;
+ }
+
+ entry->domain = irq_domain_add_linear(node, 32, &smsm_irq_ops, entry);
+ if (!entry->domain) {
+ dev_err(smsm->dev, "failed to add irq_domain\n");
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+/**
+ * smsm_get_size_info() - parse the optional memory segment for sizes
+ * @smsm: smsm driver context
+ *
+ * Attempt to acquire the number of hosts and entries from the optional shared
+ * memory location. Not being able to find this segment should indicate that
+ * we're on a older system where these values was hard coded to
+ * SMSM_DEFAULT_NUM_ENTRIES and SMSM_DEFAULT_NUM_HOSTS.
+ *
+ * Returns 0 on success, negative errno on failure.
+ */
+static int smsm_get_size_info(struct qcom_smsm *smsm)
+{
+ size_t size;
+ int ret;
+ struct {
+ u32 num_hosts;
+ u32 num_entries;
+ u32 reserved0;
+ u32 reserved1;
+ } *info;
+
+ ret = qcom_smem_get(QCOM_SMEM_HOST_ANY, SMEM_SMSM_SIZE_INFO,
+ (void **)&info, &size);
+ if (ret == -ENOENT || size != sizeof(*info)) {
+ dev_warn(smsm->dev, "no smsm size info, using defaults\n");
+ smsm->num_entries = SMSM_DEFAULT_NUM_ENTRIES;
+ smsm->num_hosts = SMSM_DEFAULT_NUM_HOSTS;
+ return 0;
+ } else if (ret) {
+ dev_err(smsm->dev, "unable to retrieve smsm size info\n");
+ return ret;
+ }
+
+ smsm->num_entries = info->num_entries;
+ smsm->num_hosts = info->num_hosts;
+
+ dev_dbg(smsm->dev,
+ "found custom size of smsm: %d entries %d hosts\n",
+ smsm->num_entries, smsm->num_hosts);
+
+ return 0;
+}
+
+static int qcom_smsm_probe(struct platform_device *pdev)
+{
+ struct device_node *gpio_node;
+ struct device_node *node;
+ struct smsm_entry *entry;
+ struct qcom_smsm *smsm;
+ u32 *intr_mask;
+ size_t size;
+ u32 *states;
+ u32 id;
+ int ret;
+
+ smsm = devm_kzalloc(&pdev->dev, sizeof(*smsm), GFP_KERNEL);
+ if (!smsm)
+ return -ENOMEM;
+ smsm->dev = &pdev->dev;
+
+ ret = smsm_get_size_info(smsm);
+ if (ret)
+ return ret;
+
+ smsm->entries = devm_kcalloc(&pdev->dev,
+ smsm->num_entries,
+ sizeof(struct smsm_entry),
+ GFP_KERNEL);
+ if (!smsm->entries)
+ return -ENOMEM;
+
+ smsm->hosts = devm_kcalloc(&pdev->dev,
+ smsm->num_hosts,
+ sizeof(struct smsm_host),
+ GFP_KERNEL);
+ if (!smsm->hosts)
+ return -ENOMEM;
+
+ gpio_node = of_find_node_with_property(pdev->dev.of_node, "gpio-controller");
+ if (!gpio_node) {
+ dev_err(&pdev->dev, "no gpio-controller entry\n");
+ return -EINVAL;
+ }
+
+ of_property_read_u32(pdev->dev.of_node,
+ "qcom,local-host",
+ &smsm->local_host);
+
+ /* Parse the host properties */
+ for (id = 0; id < smsm->num_hosts; id++) {
+ ret = smsm_parse_ipc(smsm, id);
+ if (ret < 0)
+ return ret;
+ }
+
+ /* Acquire the main SMSM state vector */
+ ret = qcom_smem_alloc(QCOM_SMEM_HOST_ANY, SMEM_SMSM_SHARED_STATE,
+ smsm->num_entries * sizeof(u32));
+ if (ret < 0 && ret != -EEXIST) {
+ dev_err(&pdev->dev, "unable to allocate shared state entry\n");
+ return ret;
+ }
+
+ ret = qcom_smem_get(QCOM_SMEM_HOST_ANY, SMEM_SMSM_SHARED_STATE,
+ (void **)&states, NULL);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Unable to acquire shared state entry\n");
+ return ret;
+ }
+
+ /* Acquire the list of interrupt mask vectors */
+ size = smsm->num_entries * smsm->num_hosts * sizeof(u32);
+ ret = qcom_smem_alloc(QCOM_SMEM_HOST_ANY, SMEM_SMSM_CPU_INTR_MASK, size);
+ if (ret < 0 && ret != -EEXIST) {
+ dev_err(&pdev->dev, "unable to allocate smsm interrupt mask\n");
+ return ret;
+ }
+
+ ret = qcom_smem_get(QCOM_SMEM_HOST_ANY, SMEM_SMSM_CPU_INTR_MASK,
+ (void **)&intr_mask, NULL);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "unable to acquire shared memory interrupt mask\n");
+ return ret;
+ }
+
+ /* Setup the reference to the local state bits */
+ smsm->local_state = states + smsm->local_host;
+ smsm->subscription = intr_mask + smsm->local_host * smsm->num_hosts;
+
+ /* Register the gpio_chip */
+ smsm->chip = smsm_gpio_chip;
+ smsm->chip.base = -1;
+ smsm->chip.dev = &pdev->dev;
+ smsm->chip.label = gpio_node->name;
+ smsm->chip.ngpio = 32;
+ smsm->chip.of_node = gpio_node;
+ ret = gpiochip_add(&smsm->chip);
+ if (ret) {
+ dev_err(smsm->dev, "failed register gpiochip\n");
+ return ret;
+ }
+
+ /* Register handlers for remote processor entries of interest. */
+ for_each_available_child_of_node(pdev->dev.of_node, node) {
+ if (!of_property_read_bool(node, "interrupt-controller"))
+ continue;
+
+ ret = of_property_read_u32(node, "reg", &id);
+ if (ret || id >= smsm->num_entries) {
+ dev_err(&pdev->dev, "invalid reg of entry\n");
+ if (!ret)
+ ret = -EINVAL;
+ goto unwind_interfaces;
+ }
+ entry = &smsm->entries[id];
+
+ entry->smsm = smsm;
+ entry->remote_state = states + id;
+
+ /* Setup subscription pointers and unsubscribe to any kicks */
+ entry->subscription = intr_mask + id * smsm->num_hosts;
+ writel(0, entry->subscription + smsm->local_host);
+
+ ret = smsm_inbound_entry(smsm, entry, node);
+ if (ret < 0)
+ goto unwind_interfaces;
+ }
+
+ platform_set_drvdata(pdev, smsm);
+
+ return 0;
+
+unwind_interfaces:
+ for (id = 0; id < smsm->num_entries; id++)
+ if (smsm->entries[id].domain)
+ irq_domain_remove(smsm->entries[id].domain);
+
+ gpiochip_remove(&smsm->chip);
+
+ return ret;
+}
+
+static int qcom_smsm_remove(struct platform_device *pdev)
+{
+ struct qcom_smsm *smsm = platform_get_drvdata(pdev);
+ unsigned id;
+
+ for (id = 0; id < smsm->num_entries; id++)
+ if (smsm->entries[id].domain)
+ irq_domain_remove(smsm->entries[id].domain);
+
+ gpiochip_remove(&smsm->chip);
+
+ return 0;
+}
+
+static const struct of_device_id qcom_smsm_of_match[] = {
+ { .compatible = "qcom,smsm" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, qcom_smsm_of_match);
+
+static struct platform_driver qcom_smsm_driver = {
+ .probe = qcom_smsm_probe,
+ .remove = qcom_smsm_remove,
+ .driver = {
+ .name = "qcom-smsm",
+ .of_match_table = qcom_smsm_of_match,
+ },
+};
+module_platform_driver(qcom_smsm_driver);
+
+MODULE_DESCRIPTION("Qualcomm Shared Memory State Machine driver");
+MODULE_LICENSE("GPL v2");
--
1.8.2.2
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
