// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Generic driver for the OLPC Embedded Controller.
*
* Author: Andres Salomon <[email protected]>
*
* Copyright (C) 2011-2012 One Laptop per Child Foundation.
*/
#include <linux/completion.h>
#include <linux/debugfs.h>
#include <linux/spinlock.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/regulator/driver.h>
#include <linux/olpc-ec.h>
struct ec_cmd_desc {
u8 cmd;
u8 *inbuf, *outbuf;
size_t inlen, outlen;
int err;
struct completion finished;
struct list_head node;
void *priv;
};
struct olpc_ec_priv {
struct olpc_ec_driver *drv;
u8 version;
struct work_struct worker;
struct mutex cmd_lock;
/* DCON regulator */
bool dcon_enabled;
/* Pending EC commands */
struct list_head cmd_q;
spinlock_t cmd_q_lock;
struct dentry *dbgfs_dir;
/*
* EC event mask to be applied during suspend (defining wakeup
* sources).
*/
u16 ec_wakeup_mask;
/*
* Running an EC command while suspending means we don't always finish
* the command before the machine suspends. This means that the EC
* is expecting the command protocol to finish, but we after a period
* of time (while the OS is asleep) the EC times out and restarts its
* idle loop. Meanwhile, the OS wakes up, thinks it's still in the
* middle of the command protocol, starts throwing random things at
* the EC... and everyone's uphappy.
*/
bool suspended;
};
static struct olpc_ec_driver *ec_driver;
static struct olpc_ec_priv *ec_priv;
static void *ec_cb_arg;
void olpc_ec_driver_register(struct olpc_ec_driver *drv, void *arg)
{
ec_driver = drv;
ec_cb_arg = arg;
}
EXPORT_SYMBOL_GPL(olpc_ec_driver_register);
static void olpc_ec_worker(struct work_struct *w)
{
struct olpc_ec_priv *ec = container_of(w, struct olpc_ec_priv, worker);
struct ec_cmd_desc *desc = NULL;
unsigned long flags;
/* Grab the first pending command from the queue */
spin_lock_irqsave(&ec->cmd_q_lock, flags);
if (!list_empty(&ec->cmd_q)) {
desc = list_first_entry(&ec->cmd_q, struct ec_cmd_desc, node);
list_del(&desc->node);
}
spin_unlock_irqrestore(&ec->cmd_q_lock, flags);
/* Do we actually have anything to do? */
if (!desc)
return;
/* Protect the EC hw with a mutex; only run one cmd at a time */
mutex_lock(&ec->cmd_lock);
desc->err = ec_driver->ec_cmd(desc->cmd, desc->inbuf, desc->inlen,
desc->outbuf, desc->outlen, ec_cb_arg);
mutex_unlock(&ec->cmd_lock);
/* Finished, wake up olpc_ec_cmd() */
complete(&desc->finished);
/* Run the worker thread again in case there are more cmds pending */
schedule_work(&ec->worker);
}
/*
* Throw a cmd descripter onto the list. We now have SMP OLPC machines, so
* locking is pretty critical.
*/
static void queue_ec_descriptor(struct ec_cmd_desc *desc,
struct olpc_ec_priv *ec)
{
unsigned long flags;
INIT_LIST_HEAD(&desc->node);
spin_lock_irqsave(&ec->cmd_q_lock, flags);
list_add_tail(&desc->node, &ec->cmd_q);
spin_unlock_irqrestore(&ec->cmd_q_lock, flags);
schedule_work(&ec->worker);
}
int olpc_ec_cmd(u8 cmd, u8 *inbuf, size_t inlen, u8 *outbuf, size_t outlen)
{
struct olpc_ec_priv *ec = ec_priv;
struct ec_cmd_desc desc;
/* Driver not yet registered. */
if (!ec_driver)
return -EPROBE_DEFER;
if (WARN_ON(!ec_driver->ec_cmd))
return -ENODEV;
if (!ec)
return -ENOMEM;
/* Suspending in the middle of a command hoses things really badly */
if (WARN_ON(ec->suspended))
return -EBUSY;
might_sleep();
desc.cmd = cmd;
desc.inbuf = inbuf;
desc.outbuf = outbuf;
desc.inlen = inlen;
desc.outlen = outlen;
desc.err = 0;
init_completion(&desc.finished);
queue_ec_descriptor(&desc, ec);
/* Timeouts must be handled in the platform-specific EC hook */
wait_for_completion(&desc.finished);
/* The worker thread dequeues the cmd; no need to do anything here */
return desc.err;
}
EXPORT_SYMBOL_GPL(olpc_ec_cmd);
void olpc_ec_wakeup_set(u16 value)
{
struct olpc_ec_priv *ec = ec_priv;
if (WARN_ON(!ec))
return;
ec->ec_wakeup_mask |= value;
}
EXPORT_SYMBOL_GPL(olpc_ec_wakeup_set);
void olpc_ec_wakeup_clear(u16 value)
{
struct olpc_ec_priv *ec = ec_priv;
if (WARN_ON(!ec))
return;
ec->ec_wakeup_mask &= ~value;
}
EXPORT_SYMBOL_GPL(olpc_ec_wakeup_clear);
int olpc_ec_mask_write(u16 bits)
{
struct olpc_ec_priv *ec = ec_priv;
if (WARN_ON(!ec))
return -ENODEV;
/* EC version 0x5f adds support for wide SCI mask */
if (ec->version >= 0x5f) {
__be16 ec_word = cpu_to_be16(bits);
return olpc_ec_cmd(EC_WRITE_EXT_SCI_MASK, (void *)&ec_word, 2, NULL, 0);
} else {
u8 ec_byte = bits & 0xff;
return olpc_ec_cmd(EC_WRITE_SCI_MASK, &ec_byte, 1, NULL, 0);
}
}
EXPORT_SYMBOL_GPL(olpc_ec_mask_write);
/*
* Returns true if the compile and runtime configurations allow for EC events
* to wake the system.
*/
bool olpc_ec_wakeup_available(void)
{
if (WARN_ON(!ec_driver))
return false;
return ec_driver->wakeup_available;
}
EXPORT_SYMBOL_GPL(olpc_ec_wakeup_available);
int olpc_ec_sci_query(u16 *sci_value)
{
struct olpc_ec_priv *ec = ec_priv;
int ret;
if (WARN_ON(!ec))
return -ENODEV;
/* EC version 0x5f adds support for wide SCI mask */
if (ec->version >= 0x5f) {
__be16 ec_word;
ret = olpc_ec_cmd(EC_EXT_SCI_QUERY, NULL, 0, (void *)&ec_word, 2);
if (ret == 0)
*sci_value = be16_to_cpu(ec_word);
} else {
u8 ec_byte;
ret = olpc_ec_cmd(EC_SCI_QUERY, NULL, 0, &ec_byte, 1);
if (ret == 0)
*sci_value = ec_byte;
}
return ret;
}
EXPORT_SYMBOL_GPL(olpc_ec_sci_query);
#ifdef CONFIG_DEBUG_FS
/*
* debugfs support for "generic commands", to allow sending
* arbitrary EC commands from userspace.
*/
#define EC_MAX_CMD_ARGS (5 + 1) /* cmd byte + 5 args */
#define EC_MAX_CMD_REPLY (8)
static DEFINE_MUTEX(ec_dbgfs_lock);
static unsigned char ec_dbgfs_resp[EC_MAX_CMD_REPLY];
static unsigned int ec_dbgfs_resp_bytes;
static ssize_t ec_dbgfs_cmd_write(struct file *file, const char __user *buf,
size_t size, loff_t *ppos)
{
int i, m;
unsigned char ec_cmd[EC_MAX_CMD_ARGS];
unsigned int ec_cmd_int[EC_MAX_CMD_ARGS];
char cmdbuf[64] = "";
int ec_cmd_bytes;
mutex_lock(&ec_dbgfs_lock);
size = simple_write_to_buffer(cmdbuf, sizeof(cmdbuf), ppos, buf, size);
m = sscanf(cmdbuf, "%x:%u %x %x %x %x %x", &ec_cmd_int[0],
&ec_dbgfs_resp_bytes, &ec_cmd_int[1], &ec_cmd_int[2],
&ec_cmd_int[3], &ec_cmd_int[4], &ec_cmd_int[5]);
if (m < 2 || ec_dbgfs_resp_bytes > EC_MAX_CMD_REPLY) {
/* reset to prevent overflow on read */
ec_dbgfs_resp_bytes = 0;
pr_debug("olpc-ec: bad ec cmd: cmd:response-count [arg1 [arg2 ...]]\n");
size = -EINVAL;
goto out;
}
/* convert scanf'd ints to char */
ec_cmd_bytes = m - 2;
for (i = 0; i <= ec_cmd_bytes; i++)
ec_cmd[i] = ec_cmd_int[i];
pr_debug("olpc-ec: debugfs cmd 0x%02x with %d args %5ph, want %d returns\n",
ec_cmd[0], ec_cmd_bytes, ec_cmd + 1,
ec_dbgfs_resp_bytes);
olpc_ec_cmd(ec_cmd[0], (ec_cmd_bytes == 0) ? NULL : &ec_cmd[1],
ec_cmd_bytes, ec_dbgfs_resp, ec_dbgfs_resp_bytes);
pr_debug("olpc-ec: response %8ph (%d bytes expected)\n",
ec_dbgfs_resp, ec_dbgfs_resp_bytes);
out:
mutex_unlock(&ec_dbgfs_lock);
return size;
}
static ssize_t ec_dbgfs_cmd_read(struct file *file, char __user *buf,
size_t size, loff_t *ppos)
{
unsigned int i, r;
char *rp;
char respbuf[64];
mutex_lock(&ec_dbgfs_lock);
rp = respbuf;
rp += sprintf(rp, "%02x", ec_dbgfs_resp[0]);
for (i = 1; i < ec_dbgfs_resp_bytes; i++)
rp += sprintf(rp, ", %02x", ec_dbgfs_resp[i]);
mutex_unlock(&ec_dbgfs_lock);
rp += sprintf(rp, "\n");
r = rp - respbuf;
return simple_read_from_buffer(buf, size, ppos, respbuf, r);
}
static const struct file_operations ec_dbgfs_ops = {
.write = ec_dbgfs_cmd_write,
.read = ec_dbgfs_cmd_read,
};
static struct dentry *olpc_ec_setup_debugfs(void)
{
struct dentry *dbgfs_dir;
dbgfs_dir = debugfs_create_dir("olpc-ec", NULL);
debugfs_create_file("cmd", 0600, dbgfs_dir, NULL, &ec_dbgfs_ops);
return dbgfs_dir;
}
#else
static struct dentry *olpc_ec_setup_debugfs(void)
{
return NULL;
}
#endif /* CONFIG_DEBUG_FS */
static int olpc_ec_set_dcon_power(struct olpc_ec_priv *ec, bool state)
{
unsigned char ec_byte = state;
int ret;
if (ec->dcon_enabled == state)
return 0;
ret = olpc_ec_cmd(EC_DCON_POWER_MODE, &ec_byte, 1, NULL, 0);
if (ret)
return ret;
ec->dcon_enabled = state;
return 0;
}
static int dcon_regulator_enable(struct regulator_dev *rdev)
{
struct olpc_ec_priv *ec = rdev_get_drvdata(rdev);
return olpc_ec_set_dcon_power(ec, true);
}
static int dcon_regulator_disable(struct regulator_dev *rdev)
{
struct olpc_ec_priv *ec = rdev_get_drvdata(rdev);
return olpc_ec_set_dcon_power(ec, false);
}
static int dcon_regulator_is_enabled(struct regulator_dev *rdev)
{
struct olpc_ec_priv *ec = rdev_get_drvdata(rdev);
return ec->dcon_enabled ? 1 : 0;
}
static const struct regulator_ops dcon_regulator_ops = {
.enable = dcon_regulator_enable,
.disable = dcon_regulator_disable,
.is_enabled = dcon_regulator_is_enabled,
};
static const struct regulator_desc dcon_desc = {
.name = "dcon",
.id = 0,
.ops = &dcon_regulator_ops,
.type = REGULATOR_VOLTAGE,
.owner = THIS_MODULE,
.enable_time = 25000,
};
static int olpc_ec_probe(struct platform_device *pdev)
{
struct olpc_ec_priv *ec;
struct regulator_config config = { };
struct regulator_dev *regulator;
int err;
if (!ec_driver)
return -ENODEV;
ec = kzalloc(sizeof(*ec), GFP_KERNEL);
if (!ec)
return -ENOMEM;
ec->drv = ec_driver;
INIT_WORK(&ec->worker, olpc_ec_worker);
mutex_init(&ec->cmd_lock);
INIT_LIST_HEAD(&ec->cmd_q);
spin_lock_init(&ec->cmd_q_lock);
ec_priv = ec;
platform_set_drvdata(pdev, ec);
/* get the EC revision */
err = olpc_ec_cmd(EC_FIRMWARE_REV, NULL, 0, &ec->version, 1);
if (err)
goto error;
config.dev = pdev->dev.parent;
config.driver_data = ec;
ec->dcon_enabled = true;
regulator = devm_regulator_register(&pdev->dev, &dcon_desc, &config);
if (IS_ERR(regulator)) {
dev_err(&pdev->dev, "failed to register DCON regulator\n");
err = PTR_ERR(regulator);
goto error;
}
ec->dbgfs_dir = olpc_ec_setup_debugfs();
return 0;
error:
ec_priv = NULL;
kfree(ec);
return err;
}
static int olpc_ec_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct olpc_ec_priv *ec = platform_get_drvdata(pdev);
int err = 0;
olpc_ec_mask_write(ec->ec_wakeup_mask);
if (ec_driver->suspend)
err = ec_driver->suspend(pdev);
if (!err)
ec->suspended = true;
return err;
}
static int olpc_ec_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct olpc_ec_priv *ec = platform_get_drvdata(pdev);
ec->suspended = false;
return ec_driver->resume ? ec_driver->resume(pdev) : 0;
}
static const struct dev_pm_ops olpc_ec_pm_ops = {
.suspend_late = olpc_ec_suspend,
.resume_early = olpc_ec_resume,
};
static struct platform_driver olpc_ec_plat_driver = {
.probe = olpc_ec_probe,
.driver = {
.name = "olpc-ec",
.pm = &olpc_ec_pm_ops,
},
};
static int __init olpc_ec_init_module(void)
{
return platform_driver_register(&olpc_ec_plat_driver);
}
arch_initcall(olpc_ec_init_module);
Codebase Browser
linux