[PATCH RESEND 5/9] Platform: OLPC: add a suspended flag to the ECdriver

From: Andres Salomon
Date: Thu Jul 19 2012 - 00:40:44 EST



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@xxxxxxxxxx>
---
drivers/platform/olpc/olpc-ec.c | 46 ++++++++++++++++++++++++++++++++++++++-
1 files changed, 45 insertions(+), 1 deletions(-)

diff --git a/drivers/platform/olpc/olpc-ec.c b/drivers/platform/olpc/olpc-ec.c
index d00523c..cfba41f 100644
--- a/drivers/platform/olpc/olpc-ec.c
+++ b/drivers/platform/olpc/olpc-ec.c
@@ -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;
}

--
1.7.2.5

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