libertas: convert libertas driver to use an event/cmdresp queue
This patch (co-developed by Dan Williams and Holger Schurig) uses a kfifo
object for events and a swapping buffer scheme for the command response to
preserve the zero-copy semantics of the CF driver and keep memory usage low.
The main thread should only ever touch the buffer indexed by priv->resp_idx,
while the interface code is free to write to the second buffer, then swap
priv->resp_idx under the driver spinlock. The firmware specs only permit
one in-flight command, so there will only ever be one command response to
process at a time.
Signed-off-by: Holger Schurig <hs4233@mail.mn-solutions.de>
Signed-off-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/libertas/cmd.c b/drivers/net/wireless/libertas/cmd.c
index 4a82f51..49267ed 100644
--- a/drivers/net/wireless/libertas/cmd.c
+++ b/drivers/net/wireless/libertas/cmd.c
@@ -4,6 +4,7 @@
*/
#include <net/iw_handler.h>
+#include <linux/kfifo.h>
#include "host.h"
#include "hostcmd.h"
#include "decl.h"
@@ -1829,15 +1830,20 @@
ret = priv->hw_host_to_card(priv, MVMS_CMD, (u8 *) &confirm_sleep,
sizeof(confirm_sleep));
-
if (ret) {
lbs_pr_alert("confirm_sleep failed\n");
- } else {
- spin_lock_irqsave(&priv->driver_lock, flags);
- if (!priv->intcounter)
- priv->psstate = PS_STATE_SLEEP;
- spin_unlock_irqrestore(&priv->driver_lock, flags);
+ goto out;
}
+
+ spin_lock_irqsave(&priv->driver_lock, flags);
+
+ /* If nothing to do, go back to sleep (?) */
+ if (!__kfifo_len(priv->event_fifo) && !priv->resp_len[priv->resp_idx])
+ priv->psstate = PS_STATE_SLEEP;
+
+ spin_unlock_irqrestore(&priv->driver_lock, flags);
+
+out:
lbs_deb_leave(LBS_DEB_HOST);
}
@@ -1899,13 +1905,16 @@
}
spin_lock_irqsave(&priv->driver_lock, flags);
+ /* In-progress command? */
if (priv->cur_cmd) {
allowed = 0;
lbs_deb_host("cur_cmd was set\n");
}
- if (priv->intcounter > 0) {
+
+ /* Pending events or command responses? */
+ if (__kfifo_len(priv->event_fifo) || priv->resp_len[priv->resp_idx]) {
allowed = 0;
- lbs_deb_host("intcounter %d\n", priv->intcounter);
+ lbs_deb_host("pending events or command responses\n");
}
spin_unlock_irqrestore(&priv->driver_lock, flags);