DM9000: Fix delays used by EEPROM read and write

The code was using a delay of 8ms, when it should have been
using the EEPROM status flag from the device to indicate the
EEPROM transaction had finished.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 51 insertions, 3 deletions

diff --git a/drivers/net/dm9000.c b/drivers/net/dm9000.c
index 851618338b2e..1d790a8e3a98 100644
--- a/drivers/net/dm9000.c
+++ b/drivers/net/dm9000.c
@@ -1048,6 +1048,50 @@ dm9000_rx(struct net_device *dev)
         } while (rxbyte == DM9000_PKT_RDY);
 }
 
+static unsigned int
+dm9000_read_locked(board_info_t *db, int reg)
+{
+        unsigned long flags;
+        unsigned int ret;
+
+        spin_lock_irqsave(&db->lock, flags);
+        ret = ior(db, reg);
+        spin_unlock_irqrestore(&db->lock, flags);
+
+        return ret;
+}
+
+static int dm9000_wait_eeprom(board_info_t *db)
+{
+        unsigned int status;
+        int timeout = 8;        /* wait max 8msec */
+
+        /* The DM9000 data sheets say we should be able to
+         * poll the ERRE bit in EPCR to wait for the EEPROM
+         * operation. From testing several chips, this bit
+         * does not seem to work. 
+         *
+         * We attempt to use the bit, but fall back to the
+         * timeout (which is why we do not return an error
+         * on expiry) to say that the EEPROM operation has
+         * completed.
+         */
+
+        while (1) {
+                status = dm9000_read_locked(db, DM9000_EPCR);
+
+                if ((status & EPCR_ERRE) == 0)
+                        break;
+
+                if (timeout-- < 0) {
+                        dev_dbg(db->dev, "timeout waiting EEPROM\n");
+                        break;
+                }
+        }
+
+        return 0;
+}
+
 /*
  *  Read a word data from EEPROM
  */
@@ -1065,8 +1109,10 @@ dm9000_read_eeprom(board_info_t *db, int offset, u8 *to)
 
         spin_unlock_irqrestore(&db->lock, flags);
 
-        mdelay(8);              /* according to the datasheet 200us should be enough,
-                                   but it doesn't work */
+        dm9000_wait_eeprom(db);
+
+        /* delay for at-least 150uS */
+        msleep(1);
 
         spin_lock_irqsave(&db->lock, flags);
 
@@ -1097,7 +1143,9 @@ dm9000_write_eeprom(board_info_t *db, int offset, u8 *data)
         iow(db, DM9000_EPCR, EPCR_WEP | EPCR_ERPRW);
         spin_unlock_irqrestore(&db->lock, flags);
 
-        mdelay(8);              /* same shit */
+        dm9000_wait_eeprom(db);
+
+        mdelay(1);      /* wait at least 150uS to clear */
 
         spin_lock_irqsave(&db->lock, flags);
         iow(db, DM9000_EPCR, 0);