--- /dev/null
+/*
+ * Generic driver for the OLPC Embedded Controller.
+ *
+ * Copyright (C) 2011-2012 One Laptop per Child Foundation.
+ *
+ * Licensed under the GPL v2 or later.
+ */
+#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/module.h>
+#include <linux/list.h>
+#include <linux/olpc-ec.h>
+#include <asm/olpc.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;
+ struct work_struct worker;
+ struct mutex cmd_lock;
+
+ /* Pending EC commands */
+ struct list_head cmd_q;
+ spinlock_t cmd_q_lock;
+
+ struct dentry *dbgfs_dir;
+
+ /*
+ * 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;
+
+ /* Ensure a driver and ec hook have been registered */
+ if (WARN_ON(!ec_driver || !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);
+
+#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 %02x %02x %02x %02x %02x, want %d returns\n",
+ ec_cmd[0], ec_cmd_bytes, ec_cmd[1], ec_cmd[2],
+ ec_cmd[3], ec_cmd[4], ec_cmd[5], 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 %02x %02x %02x %02x %02x %02x %02x %02x (%d bytes expected)\n",
+ ec_dbgfs_resp[0], ec_dbgfs_resp[1], ec_dbgfs_resp[2],
+ ec_dbgfs_resp[3], ec_dbgfs_resp[4], ec_dbgfs_resp[5],
+ ec_dbgfs_resp[6], ec_dbgfs_resp[7],
+ 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);
+ if (IS_ERR_OR_NULL(dbgfs_dir))
+ return 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_probe(struct platform_device *pdev)
+{
+ struct olpc_ec_priv *ec;
+ 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);
+
+ err = ec_driver->probe ? ec_driver->probe(pdev) : 0;
+ if (err) {
+ ec_priv = NULL;
+ kfree(ec);
+ } else {
+ ec->dbgfs_dir = olpc_ec_setup_debugfs();
+ }
+
+ 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;
+
+ 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);
+
+MODULE_AUTHOR("Andres Salomon <dilinger@queued.net>");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff