From: hartkopp <hartkopp@030b6a49-0b11-0410-94ab-b0dab22257f2>
Date: Wed, 19 May 2010 16:21:00 +0000 (+0000)
Subject: Make protected command register access CONFIG_SMP unconditional.
X-Git-Url: https://rtime.felk.cvut.cz/gitweb/socketcan-devel.git/commitdiff_plain/37168324d75832e25bdb00cec96b383ea537a6be

Make protected command register access CONFIG_SMP unconditional.
Added missing spin_lock_init() for the defined locking variable.


git-svn-id: svn://svn.berlios.de//socketcan/trunk@1181 030b6a49-0b11-0410-94ab-b0dab22257f2
---

diff --git a/kernel/2.6/drivers/net/can/sja1000/sja1000.c b/kernel/2.6/drivers/net/can/sja1000/sja1000.c
index 5ba308d..59183cb 100644
--- a/kernel/2.6/drivers/net/can/sja1000/sja1000.c
+++ b/kernel/2.6/drivers/net/can/sja1000/sja1000.c
@@ -90,23 +90,16 @@ static struct can_bittiming_const sja1000_bittiming_const = {
 
 static void sja1000_write_cmdreg(struct sja1000_priv *priv, u8 val)
 {
-	/* the command register needs some locking on SMP systems */
-
-#ifdef CONFIG_SMP
-
 	unsigned long flags;
 
+	/*
+	 * The command register needs some locking and time to settle
+	 * the write_reg() operation - especially on SMP systems.
+	 */
 	spin_lock_irqsave(&priv->cmdreg_lock, flags);
 	priv->write_reg(priv, REG_CMR, val);
 	priv->read_reg(priv, REG_SR);
 	spin_unlock_irqrestore(&priv->cmdreg_lock, flags);
-
-#else
-
-	/* write to the command register without locking */
-	priv->write_reg(priv, REG_CMR, val);
-
-#endif
 }
 
 static int sja1000_probe_chip(struct net_device *dev)
@@ -644,6 +637,8 @@ struct net_device *alloc_sja1000dev(int sizeof_priv)
 	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |
 		CAN_CTRLMODE_BERR_REPORTING;
 
+	spin_lock_init(&priv->cmdreg_lock);
+
 	if (sizeof_priv)
 		priv->priv = (void *)priv + sizeof(struct sja1000_priv);
 
diff --git a/kernel/2.6/drivers/net/can/sja1000/sja1000.h b/kernel/2.6/drivers/net/can/sja1000/sja1000.h
index 6720b37..b9dfcb8 100644
--- a/kernel/2.6/drivers/net/can/sja1000/sja1000.h
+++ b/kernel/2.6/drivers/net/can/sja1000/sja1000.h
@@ -167,10 +167,8 @@ struct sja1000_priv {
 
 	void __iomem *reg_base;	 /* ioremap'ed address to registers */
 	unsigned long irq_flags; /* for request_irq() */
+	spinlock_t cmdreg_lock;  /* lock for concurrent cmd register writes */
 
-#ifdef CONFIG_SMP
-	spinlock_t cmdreg_lock; /* lock for concurrent cmd register writes */
-#endif
 
 	u16 flags;		/* custom mode flags */
 	u8 ocr;			/* output control register */