From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757346AbYIDVti (ORCPT ); Thu, 4 Sep 2008 17:49:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755116AbYIDVso (ORCPT ); Thu, 4 Sep 2008 17:48:44 -0400 Received: from suva.vyatta.com ([69.59.150.140]:39264 "EHLO suva.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754875AbYIDVsl (ORCPT ); Thu, 4 Sep 2008 17:48:41 -0400 X-Greylist: delayed 2714 seconds by postgrey-1.27 at vger.kernel.org; Thu, 04 Sep 2008 17:48:36 EDT Message-Id: <20080904205718.543005986@vyatta.com> References: <20080904205636.130211023@vyatta.com> User-Agent: quilt/0.46-1 Date: Thu, 04 Sep 2008 13:56:37 -0700 From: Stephen Hemminger To: Jesse Barnes , Ben Hutchings Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/3] PCI: vpd handle longer delays in access Content-Disposition: inline; filename=vpd-delay.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Accessing the VPD area can take a long time. The existing VPD access code fails consistently on my hardware. There are comments in the SysKonnect vendor driver that it can take up to 13ms per word. Change the access routines to: * use a mutex rather than spinning with IRQ's disabled and lock held * have a longer timeout * call schedule while spinning to provide some responsivness Signed-off-by: Stephen Hemminger --- a/drivers/pci/access.c 2008-09-04 09:06:51.000000000 -0700 +++ b/drivers/pci/access.c 2008-09-04 10:16:52.000000000 -0700 @@ -133,7 +133,7 @@ PCI_USER_WRITE_CONFIG(dword, u32) struct pci_vpd_pci22 { struct pci_vpd base; - spinlock_t lock; /* controls access to hardware and the flags */ + struct mutex lock; u8 cap; bool busy; bool flag; /* value of F bit to wait for */ @@ -144,29 +144,33 @@ static int pci_vpd_pci22_wait(struct pci { struct pci_vpd_pci22 *vpd = container_of(dev->vpd, struct pci_vpd_pci22, base); - u16 flag, status; - int wait; + u16 flag = vpd->flag ? PCI_VPD_ADDR_F : 0; + unsigned long timeout = jiffies + (vpd->flag ? HZ/50 : HZ/10); + u16 status; int ret; if (!vpd->busy) return 0; - flag = vpd->flag ? PCI_VPD_ADDR_F : 0; - wait = vpd->flag ? 10 : 1000; /* read: 100 us; write: 10 ms */ for (;;) { - ret = pci_user_read_config_word(dev, - vpd->cap + PCI_VPD_ADDR, + ret = pci_user_read_config_word(dev, vpd->cap + PCI_VPD_ADDR, &status); if (ret < 0) - return ret; + break; + if ((status & PCI_VPD_ADDR_F) == flag) { vpd->busy = false; - return 0; + break; } - if (wait-- == 0) + + if (time_after(jiffies, timeout)) return -ETIMEDOUT; - udelay(10); + if (signal_pending(current)) + return -EINTR; + yield(); } + + return ret; } static int pci_vpd_pci22_read(struct pci_dev *dev, int pos, int size, @@ -183,7 +187,9 @@ static int pci_vpd_pci22_read(struct pci if (size == 0) return 0; - spin_lock_irq(&vpd->lock); + ret = mutex_lock_killable(&vpd->lock); + if (ret) + return ret; ret = pci_vpd_pci22_wait(dev); if (ret < 0) goto out; @@ -199,7 +205,7 @@ static int pci_vpd_pci22_read(struct pci ret = pci_user_read_config_dword(dev, vpd->cap + PCI_VPD_DATA, &val); out: - spin_unlock_irq(&vpd->lock); + mutex_unlock(&vpd->lock); if (ret < 0) return ret; @@ -231,7 +237,9 @@ static int pci_vpd_pci22_write(struct pc val |= ((u8) *buf++) << 16; val |= ((u32)(u8) *buf++) << 24; - spin_lock_irq(&vpd->lock); + ret = mutex_lock_killable(&vpd->lock); + if (ret) + return ret; ret = pci_vpd_pci22_wait(dev); if (ret < 0) goto out; @@ -247,7 +255,7 @@ static int pci_vpd_pci22_write(struct pc vpd->flag = 0; ret = pci_vpd_pci22_wait(dev); out: - spin_unlock_irq(&vpd->lock); + mutex_unlock(&vpd->lock); if (ret < 0) return ret; @@ -279,7 +287,7 @@ int pci_vpd_pci22_init(struct pci_dev *d vpd->base.len = PCI_VPD_PCI22_SIZE; vpd->base.ops = &pci_vpd_pci22_ops; - spin_lock_init(&vpd->lock); + mutex_init(&vpd->lock); vpd->cap = cap; vpd->busy = false; dev->vpd = &vpd->base; --