caif-hsi: Make inactivity timeout configurable.

CAIF HSI uses a timer for inactivity. Upon timeout HSI-wake signaling
is initiated to allow power-down of the HSI block.

Signed-off-by: Sjur Brændeland <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/caif/caif_hsi.c

···
 #define PAD_POW2(x, pow) ((((x)&((pow)-1)) == 0) ? 0 :\
 				(((pow)-((x)&((pow)-1)))))
 
+static int inactivity_timeout = 1000;
+module_param(inactivity_timeout, int, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(inactivity_timeout, "Inactivity timeout on HSI, ms.");
+
 /*
  * HSI padding options.
  * Warning: must be a base of 2 (& operation used) and can not be zero !
···
 	}
 	cfhsi->tx_state = CFHSI_TX_STATE_IDLE;
 	if (!test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
-		mod_timer(&cfhsi->timer, jiffies + CFHSI_INACTIVITY_TOUT);
+		mod_timer(&cfhsi->timer,
+			jiffies + cfhsi->inactivity_timeout);
 	spin_unlock_bh(&cfhsi->lock);
 }
 
···
 				cfhsi->tx_state = CFHSI_TX_STATE_IDLE;
 				/* Start inactivity timer. */
 				mod_timer(&cfhsi->timer,
-					jiffies + CFHSI_INACTIVITY_TOUT);
+					jiffies + cfhsi->inactivity_timeout);
 				spin_unlock_bh(&cfhsi->lock);
 				goto done;
 			}
···
 
 	/* Update inactivity timer if pending. */
 	spin_lock_bh(&cfhsi->lock);
-	mod_timer_pending(&cfhsi->timer, jiffies + CFHSI_INACTIVITY_TOUT);
+	mod_timer_pending(&cfhsi->timer,
+			jiffies + cfhsi->inactivity_timeout);
 	spin_unlock_bh(&cfhsi->lock);
 
 	if (cfhsi->rx_state.state == CFHSI_RX_STATE_DESC) {
···
 			__func__);
 		/* Start inactivity timer. */
 		mod_timer(&cfhsi->timer,
-				jiffies + CFHSI_INACTIVITY_TOUT);
+				jiffies + cfhsi->inactivity_timeout);
 		spin_unlock_bh(&cfhsi->lock);
 		return;
 	}
···
 		goto err_alloc_rx;
 	}
 
-	/* Initialize receive variables. */
+	/* Pre-calculate inactivity timeout. */
+	if (inactivity_timeout != -1) {
+		cfhsi->inactivity_timeout =
+				inactivity_timeout * HZ / 1000;
+		if (!cfhsi->inactivity_timeout)
+			cfhsi->inactivity_timeout = 1;
+		else if (cfhsi->inactivity_timeout > NEXT_TIMER_MAX_DELTA)
+			cfhsi->inactivity_timeout = NEXT_TIMER_MAX_DELTA;
+	} else {
+		cfhsi->inactivity_timeout = NEXT_TIMER_MAX_DELTA;
+	}
+
+	/* Initialize recieve vaiables. */
 	cfhsi->rx_ptr = cfhsi->rx_buf;
 	cfhsi->rx_len = CFHSI_DESC_SZ;
 

include/net/caif/caif_hsi.h

···
 	struct cfhsi_dev *dev;
 	int tx_state;
 	struct cfhsi_rx_state rx_state;
+	unsigned long inactivity_timeout;
 	int rx_len;
 	u8 *rx_ptr;
 	u8 *tx_buf;