From 39c341a8dcf060b246b0beddac90cd7de11d4a20 Mon Sep 17 00:00:00 2001 From: Ben Dooks Date: Tue, 5 Feb 2008 00:02:17 +0000 Subject: [PATCH] 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 Signed-off-by: Jeff Garzik --- drivers/net/dm9000.c | 54 +++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 51 insertions(+), 3 deletions(-) diff --git a/drivers/net/dm9000.c b/drivers/net/dm9000.c index 851618338b..1d790a8e3a 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); -- 2.39.5