wimax/i2400m: Implement pre/post reset support in the USB driver

The USB stack can callback a driver is about to be reset by an
external entity and right after it, so the driver can save state and
then restore it.

This commit implements said support; it is implemented actually in the
core, bus-generic driver [i2400m_{pre,post}_reset()] and used by the
bus-specific drivers. This way the SDIO driver can also use it once
said support is brought to the SDIO stack.

Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>

diff --git a/drivers/net/wimax/i2400m/driver.c b/drivers/net/wimax/i2400m/driver.c
index 4fcdb18..1f6aa2a 100644 (file)
--- a/drivers/net/wimax/i2400m/driver.c
+++ b/drivers/net/wimax/i2400m/driver.c
@@ -620,6 +620,87 @@ int i2400m_pm_notifier(struct notifier_block *notifier,
 
 
 /*
+ * pre-reset is called before a device is going on reset
+ *
+ * This has to be followed by a call to i2400m_post_reset(), otherwise
+ * bad things might happen.
+ */
+int i2400m_pre_reset(struct i2400m *i2400m)
+{
+       int result;
+       struct device *dev = i2400m_dev(i2400m);
+
+       d_fnstart(3, dev, "(i2400m %p)\n", i2400m);
+       d_printf(1, dev, "pre-reset shut down\n");
+
+       result = 0;
+       mutex_lock(&i2400m->init_mutex);
+       if (i2400m->updown) {
+               netif_tx_disable(i2400m->wimax_dev.net_dev);
+               __i2400m_dev_stop(i2400m);
+               result = 0;
+               /* down't set updown to zero -- this way
+                * post_reset can restore properly */
+       }
+       mutex_unlock(&i2400m->init_mutex);
+       if (i2400m->bus_release)
+               i2400m->bus_release(i2400m);
+       d_fnend(3, dev, "(i2400m %p) = %d\n", i2400m, result);
+       return result;
+}
+EXPORT_SYMBOL_GPL(i2400m_pre_reset);
+
+
+/*
+ * Restore device state after a reset
+ *
+ * Do the work needed after a device reset to bring it up to the same
+ * state as it was before the reset.
+ *
+ * NOTE: this requires i2400m->init_mutex taken
+ */
+int i2400m_post_reset(struct i2400m *i2400m)
+{
+       int result = 0;
+       struct device *dev = i2400m_dev(i2400m);
+
+       d_fnstart(3, dev, "(i2400m %p)\n", i2400m);
+       d_printf(1, dev, "post-reset start\n");
+       if (i2400m->bus_setup) {
+               result = i2400m->bus_setup(i2400m);
+               if (result < 0) {
+                       dev_err(dev, "bus-specific setup failed: %d\n",
+                               result);
+                       goto error_bus_setup;
+               }
+       }
+       mutex_lock(&i2400m->init_mutex);
+       if (i2400m->updown) {
+               result = __i2400m_dev_start(
+                       i2400m, I2400M_BRI_SOFT | I2400M_BRI_MAC_REINIT);
+               if (result < 0)
+                       goto error_dev_start;
+       }
+       mutex_unlock(&i2400m->init_mutex);
+       d_fnend(3, dev, "(i2400m %p) = %d\n", i2400m, result);
+       return result;
+
+error_dev_start:
+       if (i2400m->bus_release)
+               i2400m->bus_release(i2400m);
+error_bus_setup:
+       /* even if the device was up, it could not be recovered, so we
+        * mark it as down. */
+       i2400m->updown = 0;
+       wmb();          /* see i2400m->updown's documentation  */
+       mutex_unlock(&i2400m->init_mutex);
+       d_fnend(3, dev, "(i2400m %p) = %d\n", i2400m, result);
+       return result;
+}
+EXPORT_SYMBOL_GPL(i2400m_post_reset);
+
+
+/*
  * The device has rebooted; fix up the device and the driver
  *
  * Tear down the driver communication with the device, reload the

diff --git a/drivers/net/wimax/i2400m/i2400m.h b/drivers/net/wimax/i2400m/i2400m.h
index 1724955..8fc8a0c 100644 (file)
--- a/drivers/net/wimax/i2400m/i2400m.h
+++ b/drivers/net/wimax/i2400m/i2400m.h
@@ -817,6 +817,8 @@ void i2400m_put(struct i2400m *i2400m)
 }
 
 extern int i2400m_dev_reset_handle(struct i2400m *, const char *);
+extern int i2400m_pre_reset(struct i2400m *);
+extern int i2400m_post_reset(struct i2400m *);
 
 /*
  * _setup()/_release() are called by the probe/disconnect functions of

diff --git a/drivers/net/wimax/i2400m/usb.c b/drivers/net/wimax/i2400m/usb.c
index 7756797..8b246cc 100644 (file)
--- a/drivers/net/wimax/i2400m/usb.c
+++ b/drivers/net/wimax/i2400m/usb.c
@@ -637,6 +637,37 @@ int i2400mu_reset_resume(struct usb_interface *iface)
 }
 
 
+/*
+ * Another driver or user space is triggering a reset on the device
+ * which contains the interface passed as an argument. Cease IO and
+ * save any device state you need to restore.
+ *
+ * If you need to allocate memory here, use GFP_NOIO or GFP_ATOMIC, if
+ * you are in atomic context.
+ */
+static
+int i2400mu_pre_reset(struct usb_interface *iface)
+{
+       struct i2400mu *i2400mu = usb_get_intfdata(iface);
+       return i2400m_pre_reset(&i2400mu->i2400m);
+}
+
+
+/*
+ * The reset has completed.  Restore any saved device state and begin
+ * using the device again.
+ *
+ * If you need to allocate memory here, use GFP_NOIO or GFP_ATOMIC, if
+ * you are in atomic context.
+ */
+static
+int i2400mu_post_reset(struct usb_interface *iface)
+{
+       struct i2400mu *i2400mu = usb_get_intfdata(iface);
+       return i2400m_post_reset(&i2400mu->i2400m);
+}
+
+
 static
 struct usb_device_id i2400mu_id_table[] = {
        { USB_DEVICE(0x8086, USB_DEVICE_ID_I6050) },
@@ -660,6 +691,8 @@ struct usb_driver i2400mu_driver = {
        .reset_resume = i2400mu_reset_resume,
        .probe = i2400mu_probe,
        .disconnect = i2400mu_disconnect,
+       .pre_reset = i2400mu_pre_reset,
+       .post_reset = i2400mu_post_reset,
        .id_table = i2400mu_id_table,
        .supports_autosuspend = 1,
 };