From patchwork Thu Mar 26 17:14:36 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steve Glendinning X-Patchwork-Id: 25161 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by ozlabs.org (Postfix) with ESMTP id 3422CDDE0E for ; Fri, 27 Mar 2009 04:14:47 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754414AbZCZROg (ORCPT ); Thu, 26 Mar 2009 13:14:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752532AbZCZROg (ORCPT ); Thu, 26 Mar 2009 13:14:36 -0400 Received: from drevil.shawell.net ([86.54.240.115]:33646 "EHLO drevil2.shawell.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751167AbZCZROf (ORCPT ); Thu, 26 Mar 2009 13:14:35 -0400 Received: from localhost.localdomain (kensington.shawell.net [10.0.20.15]) by drevil2.shawell.net (Postfix) with ESMTP id 2717D3789B; Thu, 26 Mar 2009 17:14:32 +0000 (GMT) From: Steve Glendinning To: netdev@vger.kernel.org Cc: Ian Saturley , David Miller , Steve Glendinning Subject: [PATCH] smsc911x: enforce read-after-write timing restriction on eeprom access Date: Thu, 26 Mar 2009 17:14:36 +0000 Message-Id: <1238087676-14194-1-git-send-email-steve.glendinning@smsc.com> X-Mailer: git-send-email 1.6.0.6 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The LAN911x datasheet specifies a minimum delay of 45ns between a write of E2P_DATA and any read. This patch adds a single dummy read of BYTE_TEST to enforce this timing constraint. Signed-off-by: Steve Glendinning --- drivers/net/smsc911x.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) diff --git a/drivers/net/smsc911x.c b/drivers/net/smsc911x.c index ad3cbc9..af8f60c 100644 --- a/drivers/net/smsc911x.c +++ b/drivers/net/smsc911x.c @@ -1680,6 +1680,7 @@ static int smsc911x_eeprom_write_location(struct smsc911x_data *pdata, u8 address, u8 data) { u32 op = E2P_CMD_EPC_CMD_ERASE_ | address; + u32 temp; int ret; SMSC_TRACE(DRV, "address 0x%x, data 0x%x", address, data); @@ -1688,6 +1689,10 @@ static int smsc911x_eeprom_write_location(struct smsc911x_data *pdata, if (!ret) { op = E2P_CMD_EPC_CMD_WRITE_ | address; smsc911x_reg_write(pdata, E2P_DATA, (u32)data); + + /* Workaround for hardware read-after-write restriction */ + temp = smsc911x_reg_read(pdata, BYTE_TEST); + ret = smsc911x_eeprom_send_cmd(pdata, op); }