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>

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 @@ static void lbs_send_confirmsleep(struct lbs_private *priv)
 
 	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 @@ void lbs_ps_confirm_sleep(struct lbs_private *priv)
 	}
 
 	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);
 

drivers/net/wireless/libertas/cmdresp.c

@@ -384,7 +384,7 @@ static inline int handle_cmd_response(struct lbs_private *priv,
 	return ret;
 }
 
-int lbs_process_rx_command(struct lbs_private *priv)
+int lbs_process_command_response(struct lbs_private *priv, u8 *data, u32 len)
 {
 	uint16_t respcmd, curcmd;
 	struct cmd_header *resp;
@@ -404,14 +404,14 @@ int lbs_process_rx_command(struct lbs_private *priv)
 		goto done;
 	}
 
-	resp = (void *)priv->upld_buf;
+	resp = (void *)data;
 	curcmd = le16_to_cpu(priv->cur_cmd->cmdbuf->command);
 	respcmd = le16_to_cpu(resp->command);
 	result = le16_to_cpu(resp->result);
 
 	lbs_deb_cmd("CMD_RESP: response 0x%04x, seq %d, size %d\n",
-		     respcmd, le16_to_cpu(resp->seqnum), priv->upld_len);
-	lbs_deb_hex(LBS_DEB_CMD, "CMD_RESP", (void *) resp, priv->upld_len);
+		     respcmd, le16_to_cpu(resp->seqnum), len);
+	lbs_deb_hex(LBS_DEB_CMD, "CMD_RESP", (void *) resp, len);
 
 	if (resp->seqnum != priv->cur_cmd->cmdbuf->seqnum) {
 		lbs_pr_info("Received CMD_RESP with invalid sequence %d (expected %d)\n",
@@ -569,18 +569,13 @@ static int lbs_send_confirmwake(struct lbs_private *priv)
 	return ret;
 }
 
-int lbs_process_event(struct lbs_private *priv)
+int lbs_process_event(struct lbs_private *priv, u32 event)
 {
 	int ret = 0;
-	u32 eventcause;
 
 	lbs_deb_enter(LBS_DEB_CMD);
 
-	spin_lock_irq(&priv->driver_lock);
-	eventcause = priv->eventcause >> SBI_EVENT_CAUSE_SHIFT;
-	spin_unlock_irq(&priv->driver_lock);
-
-	switch (eventcause) {
+	switch (event) {
 	case MACREG_INT_CODE_LINK_SENSED:
 		lbs_deb_cmd("EVENT: link sensed\n");
 		break;
@@ -696,14 +691,10 @@ int lbs_process_event(struct lbs_private *priv)
 		break;
 
 	default:
-		lbs_pr_alert("EVENT: unknown event id %d\n", eventcause);
+		lbs_pr_alert("EVENT: unknown event id %d\n", event);
 		break;
 	}
 
-	spin_lock_irq(&priv->driver_lock);
-	priv->eventcause = 0;
-	spin_unlock_irq(&priv->driver_lock);
-
 	lbs_deb_leave_args(LBS_DEB_CMD, "ret %d", ret);
 	return ret;
 }

drivers/net/wireless/libertas/debugfs.c

@@ -824,7 +824,6 @@ struct debug_data {
 /* To debug any member of struct lbs_private, simply add one line here.
  */
 static struct debug_data items[] = {
-	{"intcounter", item_size(intcounter), item_addr(intcounter)},
 	{"psmode", item_size(psmode), item_addr(psmode)},
 	{"psstate", item_size(psstate), item_addr(psstate)},
 };

drivers/net/wireless/libertas/decl.h

@@ -19,7 +19,7 @@ struct cmd_ds_command;
 
 void lbs_set_mac_control(struct lbs_private *priv);
 
-void lbs_send_tx_feedback(struct lbs_private *priv);
+void lbs_send_tx_feedback(struct lbs_private *priv, u32 try_count);
 
 int lbs_free_cmd_buffer(struct lbs_private *priv);
 
@@ -30,14 +30,16 @@ int lbs_prepare_and_send_command(struct lbs_private *priv,
 
 int lbs_allocate_cmd_buffer(struct lbs_private *priv);
 int lbs_execute_next_command(struct lbs_private *priv);
-int lbs_process_event(struct lbs_private *priv);
-void lbs_interrupt(struct lbs_private *priv);
+int lbs_process_event(struct lbs_private *priv, u32 event);
+void lbs_queue_event(struct lbs_private *priv, u32 event);
+void lbs_notify_command_response(struct lbs_private *priv, u8 resp_idx);
+
 int lbs_set_radio_control(struct lbs_private *priv);
 u32 lbs_fw_index_to_data_rate(u8 index);
 u8 lbs_data_rate_to_fw_index(u32 rate);
 
 /** The proc fs interface */
-int lbs_process_rx_command(struct lbs_private *priv);
+int lbs_process_command_response(struct lbs_private *priv, u8 *data, u32 len);
 void lbs_complete_command(struct lbs_private *priv, struct cmd_ctrl_node *cmd,
 			  int result);
 int lbs_hard_start_xmit(struct sk_buff *skb, struct net_device *dev);

drivers/net/wireless/libertas/defs.h

@@ -177,8 +177,6 @@ static inline void lbs_deb_hex(unsigned int grp, const char *prompt, u8 *buf, in
 #define MRVDRV_CMD_UPLD_RDY		0x0008
 #define MRVDRV_CARDEVENT		0x0010
 
-#define SBI_EVENT_CAUSE_SHIFT		3
-
 /** TxPD status */
 
 /*	Station firmware use TxPD status field to report final Tx transmit

drivers/net/wireless/libertas/dev.h

@@ -129,10 +129,6 @@ struct lbs_private {
 	u32 bbp_offset;
 	u32 rf_offset;
 
-	/** Upload length */
-	u32 upld_len;
-	/* Upload buffer */
-	u8 upld_buf[LBS_UPLD_SIZE];
 	/* Download sent:
 	   bit0 1/0=data_sent/data_tx_done,
 	   bit1 1/0=cmd_sent/cmd_tx_done,
@@ -155,21 +151,16 @@ struct lbs_private {
 
 	/** Hardware access */
 	int (*hw_host_to_card) (struct lbs_private *priv, u8 type, u8 *payload, u16 nb);
-	int (*hw_get_int_status) (struct lbs_private *priv, u8 *);
-	int (*hw_read_event_cause) (struct lbs_private *);
 
 	/* Wake On LAN */
 	uint32_t wol_criteria;
 	uint8_t wol_gpio;
 	uint8_t wol_gap;
 
-	/* was struct lbs_adapter from here... */
-
 	/** Wlan adapter data structure*/
 	/** STATUS variables */
 	u32 fwrelease;
 	u32 fwcapinfo;
-	/* protected with big lock */
 
 	struct mutex lock;
 
@@ -181,7 +172,6 @@ struct lbs_private {
 
 	/** command-related variables */
 	u16 seqnum;
-	/* protected by big lock */
 
 	struct cmd_ctrl_node *cmd_array;
 	/** Current command */
@@ -194,12 +184,17 @@ struct lbs_private {
 	struct list_head cmdpendingq;
 
 	wait_queue_head_t cmd_pending;
-	/* command related variables protected by priv->driver_lock */
 
-	/** Async and Sync Event variables */
-	u32 intcounter;
-	u32 eventcause;
-	u8 nodename[16];	/* nickname */
+	/* Command responses sent from the hardware to the driver */
+	u8 resp_idx;
+	u8 resp_buf[2][LBS_UPLD_SIZE];
+	u32 resp_len[2];
+
+	/* Events sent from hardware to driver */
+	struct kfifo *event_fifo;
+
+	/* nickname */
+	u8 nodename[16];
 
 	/** spin locks */
 	spinlock_t driver_lock;
@@ -209,8 +204,6 @@ struct lbs_private {
 	int nr_retries;
 	int cmd_timed_out;
 
-	u8 hisregcpy;
-
 	/** current ssid/bssid related parameters*/
 	struct current_bss_params curbssparams;