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Platform: OLPC: add a suspended flag to the EC driver

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A problem we've noticed on XO-1.75 is when we suspend in the middle of
an EC command.  Don't allow that.

In the process, create a private object for the generic EC driver to use;
we have a framework for passing around a struct, use that rather than a
proliferation of global variables.

Signed-off-by: Andres Salomon <dilinger@queued.net>
Acked-by: Paul Fox <pgf@laptop.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Andres Salomon 2012-07-13 15:54:25 -07:00
parent ac2504151f
commit d278b7a2f9
1 changed files with 45 additions and 1 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

46
drivers/platform/olpc/olpc-ec.c
View file

@ -9,6 +9,7 @@
#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>
@ -27,6 +28,21 @@ struct ec_cmd_desc {
void *priv;
};
struct olpc_ec_priv {
struct olpc_ec_driver *drv;
/*
* 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 void olpc_ec_worker(struct work_struct *w);
static DECLARE_WORK(ec_worker, olpc_ec_worker);
@ -34,6 +50,7 @@ static LIST_HEAD(ec_cmd_q);
static DEFINE_SPINLOCK(ec_cmd_q_lock);
static struct olpc_ec_driver *ec_driver;
static struct olpc_ec_priv *ec_priv;
static void *ec_cb_arg;
static DEFINE_MUTEX(ec_cb_lock);
@ -93,6 +110,7 @@ static void queue_ec_descriptor(struct ec_cmd_desc *desc)
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;
/* XXX: this will be removed in later patches */
@ -104,6 +122,13 @@ int olpc_ec_cmd(u8 cmd, u8 *inbuf, size_t inlen, u8 *outbuf, size_t outlen)
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;
@ -126,11 +151,19 @@ EXPORT_SYMBOL_GPL(olpc_ec_cmd);
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;
ec_priv = ec;
platform_set_drvdata(pdev, ec);
err = ec_driver->probe ? ec_driver->probe(pdev) : 0;
return err;
@ -139,12 +172,23 @@ static int olpc_ec_probe(struct platform_device *pdev)
static int olpc_ec_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
return ec_driver->suspend ? ec_driver->suspend(pdev) : 0;
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;
}