1 files changed, 39 insertions, 14 deletions

diff --git a/drivers/net/dm9000.c b/drivers/net/dm9000.c
index fa7eb39dbf3c..a769c89a3690 100644
--- a/drivers/net/dm9000.c
+++ b/drivers/net/dm9000.c
@@ -102,6 +102,24 @@ static int watchdog = 5000;
 module_param(watchdog, int, 0400);
 MODULE_PARM_DESC(watchdog, "transmit timeout in milliseconds");
 
+/* DM9000 register address locking.
+ *
+ * The DM9000 uses an address register to control where data written
+ * to the data register goes. This means that the address register
+ * must be preserved over interrupts or similar calls.
+ *
+ * During interrupt and other critical calls, a spinlock is used to
+ * protect the system, but the calls themselves save the address
+ * in the address register in case they are interrupting another
+ * access to the device.
+ *
+ * For general accesses a lock is provided so that calls which are
+ * allowed to sleep are serialised so that the address register does
+ * not need to be saved. This lock also serves to serialise access
+ * to the EEPROM and PHY access registers which are shared between
+ * these two devices.
+ */
+
 /* Structure/enum declaration ------------------------------- */
 typedef struct board_info {
 
@@ -132,6 +150,8 @@ typedef struct board_info {
         struct resource *data_req;
         struct resource *irq_res;
 
+        struct mutex     addr_lock;     /* phy and eeprom access lock */
+
         spinlock_t lock;
 
         struct mii_if_info mii;
@@ -365,26 +385,16 @@ static void dm9000_get_drvinfo(struct net_device *dev,
 static int dm9000_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
 {
         board_info_t *dm = to_dm9000_board(dev);
-        unsigned long flags;
 
-        spin_lock_irqsave(&dm->lock, flags);
         mii_ethtool_gset(&dm->mii, cmd);
-        spin_lock_irqsave(&dm->lock, flags);
-
         return 0;
 }
 
 static int dm9000_set_settings(struct net_device *dev, struct ethtool_cmd *cmd)
 {
         board_info_t *dm = to_dm9000_board(dev);
-        unsigned long flags;
-        int rc;
-
-        spin_lock_irqsave(&dm->lock, flags);
-        rc = mii_ethtool_sset(&dm->mii, cmd);
-        spin_lock_irqsave(&dm->lock, flags);
 
-        return rc;
+        return mii_ethtool_sset(&dm->mii, cmd);
 }
 
 static int dm9000_nway_reset(struct net_device *dev)
@@ -475,6 +485,7 @@ dm9000_probe(struct platform_device *pdev)
         db->dev = &pdev->dev;
 
         spin_lock_init(&db->lock);
+        mutex_init(&db->addr_lock);
 
         if (pdev->num_resources < 2) {
                 ret = -ENODEV;
@@ -997,8 +1008,10 @@ dm9000_rx(struct net_device *dev)
  *  Read a word data from EEPROM
  */
 static void
-dm9000_read_eeprom(board_info_t * db, int offset, unsigned char *to)
+dm9000_read_eeprom(board_info_t *db, int offset, unsigned char *to)
 {
+        mutex_lock(&db->addr_lock);
+
         iow(db, DM9000_EPAR, offset);
         iow(db, DM9000_EPCR, EPCR_ERPRR);
         mdelay(8);              /* according to the datasheet 200us should be enough,
@@ -1007,6 +1020,8 @@ dm9000_read_eeprom(board_info_t * db, int offset, unsigned char *to)
 
         to[0] = ior(db, DM9000_EPDRL);
         to[1] = ior(db, DM9000_EPDRH);
+
+        mutex_unlock(&db->addr_lock);
 }
 
 #ifdef DM9000_PROGRAM_EEPROM
@@ -1016,12 +1031,16 @@ dm9000_read_eeprom(board_info_t * db, int offset, unsigned char *to)
 static void
 write_srom_word(board_info_t * db, int offset, u16 val)
 {
+        mutex_lock(&db->addr_lock);
+
         iow(db, DM9000_EPAR, offset);
         iow(db, DM9000_EPDRH, ((val >> 8) & 0xff));
         iow(db, DM9000_EPDRL, (val & 0xff));
         iow(db, DM9000_EPCR, EPCR_WEP | EPCR_ERPRW);
         mdelay(8);              /* same shit */
         iow(db, DM9000_EPCR, 0);
+
+        mutex_unlock(&db->addr_lock);
 }
 
 /*
@@ -1129,6 +1148,8 @@ dm9000_phy_read(struct net_device *dev, int phy_reg_unused, int reg)
         unsigned int reg_save;
         int ret;
 
+        mutex_lock(&db->addr_lock);
+
         spin_lock_irqsave(&db->lock,flags);
 
         /* Save previous register address */
@@ -1156,6 +1177,7 @@ dm9000_phy_read(struct net_device *dev, int phy_reg_unused, int reg)
         writeb(reg_save, db->io_addr);
         spin_unlock_irqrestore(&db->lock,flags);
 
+        mutex_unlock(&db->addr_lock);
         return ret;
 }
 
@@ -1169,6 +1191,8 @@ dm9000_phy_write(struct net_device *dev, int phyaddr_unused, int reg, int value)
         unsigned long flags;
         unsigned long reg_save;
 
+        mutex_lock(&db->addr_lock);
+
         spin_lock_irqsave(&db->lock,flags);
 
         /* Save previous register address */
@@ -1184,7 +1208,7 @@ dm9000_phy_write(struct net_device *dev, int phyaddr_unused, int reg, int value)
         iow(db, DM9000_EPCR, 0xa);      /* Issue phyxcer write command */
 
         writeb(reg_save, db->io_addr);
-        spin_unlock_irqrestore(&db->lock,flags);
+        spin_unlock_irqrestore(&db->lock, flags);
 
         dm9000_msleep(db, 1);           /* Wait write complete */
 
@@ -1196,7 +1220,8 @@ dm9000_phy_write(struct net_device *dev, int phyaddr_unused, int reg, int value)
         /* restore the previous address */
         writeb(reg_save, db->io_addr);
 
-        spin_unlock_irqrestore(&db->lock,flags);
+        spin_unlock_irqrestore(&db->lock, flags);
+        mutex_unlock(&db->addr_lock);
 }
 
 static int