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>
diff --git a/drivers/net/dm9000.c b/drivers/net/dm9000.c
index 8516183..1d790a8 100644
--- a/drivers/net/dm9000.c
+++ b/drivers/net/dm9000.c
@@ -1048,6 +1048,50 @@
} 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 @@
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 @@
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);