wimax/i2400m: cache firmware on system suspend

In preparation for a reset_resume implementation, have the firmware
image be cached in memory when the system goes to suspend and released
when out.

This is needed in case the device resets during suspend; the driver
can't load firmware until resume is completed or bad deadlocks
happen.

The modus operandi for this was copied from the Orinoco USB driver.

The caching is done with a kobject to avoid race conditions when
releasing it. The fw loader path is altered only to first check for a
cached image before trying to load from disk. A Power Management event
notifier is register to call i2400m_fw_cache() or i2400m_fw_uncache()
which take care of the actual cache management.

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

1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/net/wimax/i2400m/i2400m.h b/drivers/net/wimax/i2400m/i2400m.h
index 0c165de89b2d..916b1d319299 100644
--- a/drivers/net/wimax/i2400m/i2400m.h
+++ b/drivers/net/wimax/i2400m/i2400m.h
@@ -424,11 +424,21 @@ struct i2400m_barker_db;
  * @fw_hdrs: NULL terminated array of pointers to the firmware
  *     headers. This is only available during firmware load time.
  *
+ * @fw_cached: Used to cache firmware when the system goes to
+ *     suspend/standby/hibernation (as on resume we can't read it). If
+ *     NULL, no firmware was cached, read it. If ~0, you can't read
+ *     any firmware files (the system still didn't come out of suspend
+ *     and failed to cache one), so abort; otherwise, a valid cached
+ *     firmware to be used. Access to this variable is protected by
+ *     the spinlock i2400m->rx_lock.
+ *
  * @barker: barker type that the device uses; this is initialized by
  *     i2400m_is_boot_barker() the first time it is called. Then it
  *     won't change during the life cycle of the device and everytime
  *     a boot barker is received, it is just verified for it being the
  *     same.
+ *
+ * @pm_notifier: used to register for PM events
  */
 struct i2400m {
         struct wimax_dev wimax_dev;     /* FIRST! See doc */
@@ -495,7 +505,10 @@ struct i2400m {
         const char *fw_name;            /* name of the current firmware image */
         unsigned long fw_version;       /* version of the firmware interface */
         const struct i2400m_bcf_hdr **fw_hdrs;
+        struct i2400m_fw *fw_cached;    /* protected by rx_lock */
         struct i2400m_barker_db *barker;
+
+        struct notifier_block pm_notifier;
 };
 
 
@@ -671,6 +684,9 @@ extern void i2400m_tx_release(struct i2400m *);
 extern int i2400m_rx_setup(struct i2400m *);
 extern void i2400m_rx_release(struct i2400m *);
 
+extern void i2400m_fw_cache(struct i2400m *);
+extern void i2400m_fw_uncache(struct i2400m *);
+
 extern void i2400m_net_rx(struct i2400m *, struct sk_buff *, unsigned,
                           const void *, int);
 extern void i2400m_net_erx(struct i2400m *, struct sk_buff *,