Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756625AbXLRV7o (ORCPT ); Tue, 18 Dec 2007 16:59:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754051AbXLRV7f (ORCPT ); Tue, 18 Dec 2007 16:59:35 -0500 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:35935 "EHLO ebiederm.dsl.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753691AbXLRV7e (ORCPT ); Tue, 18 Dec 2007 16:59:34 -0500 From: ebiederm@xmission.com (Eric W. Biederman) To: "peerchen" Cc: "linux-kernel" , "akpm" , "acurrid" , "pchen" Subject: Re: [PATCH] msi: set 'En' bit of MSI Mapping Capability References: <200712182300373901202@gmail.com> Date: Tue, 18 Dec 2007 14:59:08 -0700 In-Reply-To: <200712182300373901202@gmail.com> (peerchen@gmail.com's message of "Tue, 18 Dec 2007 23:00:52 +0800") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6060 Lines: 168 "peerchen" writes: > According to the HyperTransport spec, 'En' indicate if the MSI Mapping is > active. > Set the 'En' bit when setup pci and add the quirk for some nvidia devices. > > The patch base on kernel 2.6.24-rc5 Ok. This is starting to look good. > Signed-off-by: Andy Currid > Signed-off-by: Peer Chen > > --- > diff -uprN -X linux-2.6.24-rc5-vanilla/Documentation/dontdiff > linux-2.6.24-rc5-vanilla/drivers/pci/probe.c > linux-2.6.24-rc5/drivers/pci/probe.c > --- linux-2.6.24-rc5-vanilla/drivers/pci/probe.c 2007-12-18 14:35:46.000000000 > -0500 > +++ linux-2.6.24-rc5/drivers/pci/probe.c 2007-12-18 16:28:29.000000000 -0500 > @@ -721,6 +721,9 @@ static int pci_setup_device(struct pci_d > > /* "Unknown power state" */ > dev->current_state = PCI_UNKNOWN; > + > + /* Enable HT MSI mapping */ > + ht_enable_msi_mapping(dev); > > /* Early fixups, before probing the BARs */ > pci_fixup_device(pci_fixup_early, dev); > diff -uprN -X linux-2.6.24-rc5-vanilla/Documentation/dontdiff > linux-2.6.24-rc5-vanilla/drivers/pci/quirks.c > linux-2.6.24-rc5/drivers/pci/quirks.c > --- linux-2.6.24-rc5-vanilla/drivers/pci/quirks.c 2007-12-18 14:35:46.000000000 > -0500 > +++ linux-2.6.24-rc5/drivers/pci/quirks.c 2007-12-18 16:28:41.000000000 -0500 > @@ -1705,6 +1705,45 @@ static void __devinit quirk_nvidia_ck804 > DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_CK804_PCIE, > quirk_nvidia_ck804_msi_ht_cap); > > +static void __devinit quirk_msi_ht_cap_disable(struct pci_dev *dev) { > + struct pci_dev *host_bridge; > + int pos, ttl = 48; > + > + /* HT MSI mapping should be disabled on devices that are below > + * a non-Hypertransport host bridge. Locate the host bridge... > + */ > + > + if ((host_bridge = pci_get_bus_and_slot(0, PCI_DEVFN(0,0))) == NULL) { > + printk(KERN_WARNING > + "PCI: quirk_msi_ht_cap_disable didn't locate host bridge\n"); > + return; > + } > + > + if ((pos = pci_find_ht_capability(host_bridge, HT_CAPTYPE_SLAVE)) != 0) { > + /* Host bridge is to HT */ > + return; > + } > + > + /* Host bridge is not to HT, disable HT MSI mapping on this device */ > + > + pos = pci_find_ht_capability(dev, HT_CAPTYPE_MSI_MAPPING); > + while (pos && ttl--) { > + u8 flags; > + > + if (pci_read_config_byte(dev, pos + HT_MSI_FLAGS, &flags) == 0) { > + printk(KERN_INFO "PCI: Quirk disabling HT MSI mapping on %s\n", > + pci_name(dev)); > + > + pci_write_config_byte(dev, pos + HT_MSI_FLAGS, > + flags & ~HT_MSI_FLAGS_ENABLE); > + } > + pos = pci_find_next_ht_capability(dev, pos, > + HT_CAPTYPE_MSI_MAPPING); > + } > +} > +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID, > + quirk_msi_ht_cap_disable); Could you explain the need for this quirk? My expectation would be that if we turned an MSI interrupt into a hypertransport interrupt then if we hit a non-hyptransport bridge upstream it would just turn the hypertransport interrupts into whatever makes sense for the upstream bridge. I can see it being excess work and adding some latency but I don't see it being a correctness problem. Or are my expectations off and the NVIDIA chipsets do not handle hypertransport interrupts the way I would expect. Dropping them instead of converting when going to a non-hypertransport host bridge. > static void __devinit quirk_msi_intx_disable_bug(struct pci_dev *dev) > { > dev->dev_flags |= PCI_DEV_FLAGS_MSI_INTX_DISABLE_BUG; > diff -uprN -X linux-2.6.24-rc5-vanilla/Documentation/dontdiff > linux-2.6.24-rc5-vanilla/include/asm-generic/pci.h > linux-2.6.24-rc5/include/asm-generic/pci.h > --- linux-2.6.24-rc5-vanilla/include/asm-generic/pci.h 2007-12-18 > 14:35:52.000000000 -0500 > +++ linux-2.6.24-rc5/include/asm-generic/pci.h 2007-12-18 16:29:12.000000000 > -0500 > @@ -45,6 +45,10 @@ pcibios_select_root(struct pci_dev *pdev > > #define pcibios_scan_all_fns(a, b) 0 > > +#ifndef HAVE_ARCH_HT_ENABLE_MSI_MAPPING > +#define ht_enable_msi_mapping(a) 0 > +#endif /* HAVE_ARCH_HT_ENABLE_MSI_MAPPING */ > + > #ifndef HAVE_ARCH_PCI_GET_LEGACY_IDE_IRQ > static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel) > { > diff -uprN -X linux-2.6.24-rc5-vanilla/Documentation/dontdiff > linux-2.6.24-rc5-vanilla/include/asm-x86/pci.h > linux-2.6.24-rc5/include/asm-x86/pci.h > --- linux-2.6.24-rc5-vanilla/include/asm-x86/pci.h 2007-12-18 14:35:51.000000000 > -0500 > +++ linux-2.6.24-rc5/include/asm-x86/pci.h 2007-12-18 16:28:58.000000000 -0500 > @@ -75,6 +75,27 @@ static inline void pci_dma_burst_advice( > } > #endif > > +#ifdef CONFIG_PCI > +#define HAVE_ARCH_HT_ENABLE_MSI_MAPPING > +static inline void ht_enable_msi_mapping(struct pci_dev *dev) > +{ > + int pos, ttl = 48; > + > + pos = pci_find_ht_capability(dev, HT_CAPTYPE_MSI_MAPPING); > + while (pos && ttl--) { > + u8 flags; > + > + if (pci_read_config_byte(dev, pos + HT_MSI_FLAGS, &flags) == 0) { > + printk(KERN_INFO "PCI: Enabling HT MSI Mapping on %s\n", > + dev->dev.bus_id); > + > + pci_write_config_byte(dev, pos + HT_MSI_FLAGS, > + flags | HT_MSI_FLAGS_ENABLE); Here I see two things that we should do better. 1) If the BIOS has already properly enabled the capability we don't need to do anything or print any message. i.e. if (!(flags & HT_MSI_FLAGS_ENABLE)) { printk(...) pci_write_config_byte() } 2) The hypertransport specification allows for an optional register that specifies the address of the msi mapping window. If that register is present we should program it to the architectural defined address on x86 before enabling the device. > + } > + pos = pci_find_next_ht_capability(dev, pos, HT_CAPTYPE_MSI_MAPPING); > + } > +} > +#endif > > #endif /* __KERNEL__ */ > - -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/