linux/drivers/soc/qcom/smp2p.c

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/*
* 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/mailbox_client.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
* @mbox_client: mailbox client handle
* @mbox_chan: apcs ipc mailbox channel handle
* @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 mbox_client mbox_client;
struct mbox_chan *mbox_chan;
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();
if (smp2p->mbox_chan) {
mbox_send_message(smp2p->mbox_chan, NULL);
mbox_client_txdone(smp2p->mbox_chan, 0);
} else {
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(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(out->entries[out->valid_entries].name, buf, SMP2P_MAX_ENTRY_NAME);
/* Make the logical entry reference the physical value */
entry->value = &out->entries[out->valid_entries].value;
out->valid_entries++;
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);
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)
goto report_read_failure;
key = "qcom,remote-pid";
ret = of_property_read_u32(pdev->dev.of_node, key, &smp2p->remote_pid);
if (ret)
goto report_read_failure;
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(&pdev->dev, "unable to acquire smp2p interrupt\n");
return irq;
}
smp2p->mbox_client.dev = &pdev->dev;
smp2p->mbox_client.knows_txdone = true;
smp2p->mbox_chan = mbox_request_channel(&smp2p->mbox_client, 0);
if (IS_ERR(smp2p->mbox_chan)) {
if (PTR_ERR(smp2p->mbox_chan) != -ENODEV)
return PTR_ERR(smp2p->mbox_chan);
smp2p->mbox_chan = NULL;
ret = smp2p_parse_ipc(smp2p);
if (ret)
return ret;
}
ret = qcom_smp2p_alloc_outbound_item(smp2p);
if (ret < 0)
goto release_mbox;
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;
release_mbox:
mbox_free_channel(smp2p->mbox_chan);
return ret;
report_read_failure:
dev_err(&pdev->dev, "failed to read %s\n", key);
return -EINVAL;
}
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);
mbox_free_channel(smp2p->mbox_chan);
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");