soc: qcom: smp2p: Qualcomm Shared Memory Point to Point

Introduce the Qualcomm Shard Memory Point to Point driver.

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: Andy Gross <agross@codeaurora.org>

3 files changed, 587 insertions, 0 deletions

diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 2b73f2e0cba3..b57be7ab50b6 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -53,6 +53,14 @@ config QCOM_SMD_RPM
 config QCOM_SMEM_STATE
         bool
 
+config QCOM_SMP2P
+        bool "Qualcomm Shared Memory Point to Point support"
+        depends on QCOM_SMEM
+        select QCOM_SMEM_STATE
+        help
+          Say yes here to support the Qualcomm Shared Memory Point to Point
+          protocol.
+
 config QCOM_SMSM
         bool "Qualcomm Shared Memory State Machine"
         depends on QCOM_SMEM
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index 452c505dafe4..69886e0f7ef8 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -4,4 +4,5 @@ obj-$(CONFIG_QCOM_SMD) +=	smd.o
 obj-$(CONFIG_QCOM_SMD_RPM)      += smd-rpm.o
 obj-$(CONFIG_QCOM_SMEM) +=      smem.o
 obj-$(CONFIG_QCOM_SMEM_STATE) += smem_state.o
+obj-$(CONFIG_QCOM_SMP2P)        += smp2p.o
 obj-$(CONFIG_QCOM_SMSM) += smsm.o
diff --git a/drivers/soc/qcom/smp2p.c b/drivers/soc/qcom/smp2p.c
new file mode 100644
index 000000000000..f1eed7f9dd67
--- /dev/null
+++ b/drivers/soc/qcom/smp2p.c
@@ -0,0 +1,578 @@
+/*
+ * 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/interrupt.h>
+#include <linux/list.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.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/soc/qcom/smem_state.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
+ * @state:      smem state handle
+ * @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 qcom_smem_state *state;
+
+        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 i;
+
+        in = smp2p->in;
+
+        /* Acquire smem item, if not already found */
+        if (!in) {
+                in = qcom_smem_get(pid, smem_id, &size);
+                if (IS_ERR(in)) {
+                        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) && test_bit(i, entry->irq_rising)) ||
+                            (!(val & BIT(i)) && 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 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 smp2p_update_bits(void *data, u32 mask, u32 value)
+{
+        struct smp2p_entry *entry = data;
+        u32 orig;
+        u32 val;
+
+        spin_lock(&entry->lock);
+        val = orig = readl(entry->value);
+        val &= ~mask;
+        val |= value;
+        writel(val, entry->value);
+        spin_unlock(&entry->lock);
+
+        if (val != orig)
+                qcom_smp2p_kick(entry->smp2p);
+
+        return 0;
+}
+
+static const struct qcom_smem_state_ops smp2p_state_ops = {
+        .update_bits = smp2p_update_bits,
+};
+
+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] = {};
+
+        /* 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->state = qcom_smem_state_register(node, &smp2p_state_ops, entry);
+        if (IS_ERR(entry->state)) {
+                dev_err(smp2p->dev, "failed to register qcom_smem_state\n");
+                return PTR_ERR(entry->state);
+        }
+
+        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;
+        }
+
+        out = qcom_smem_get(pid, smem_id, NULL);
+        if (IS_ERR(out)) {
+                dev_err(smp2p->dev, "Unable to acquire local smp2p item\n");
+                return PTR_ERR(out);
+        }
+
+        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  {
+                        ret = qcom_smp2p_outbound_entry(smp2p, entry, node);
+                        if (ret < 0)
+                                goto unwind_interfaces;
+
+                        list_add(&entry->node, &smp2p->outbound);
+                }
+        }
+
+        /* 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)
+                qcom_smem_state_unregister(entry->state);
+
+        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)
+                qcom_smem_state_unregister(entry->state);
+
+        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");