From: David Daney Subject: Re: [PATCH 1/2] PCI/IOV: Add function to allow Function Dependency Link override. Date: Mon, 22 Aug 2016 07:49:09 -0700 Message-ID: <57BB10E5.1050506@caviumnetworks.com> References: <1471645933-3643-1-git-send-email-okhaliq@caviumnetworks.com> <1471645933-3643-2-git-send-email-okhaliq@caviumnetworks.com> <20160822143637.GA18628@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Cc: Omer Khaliq , , , , , , , , , To: Bjorn Helgaas Return-path: In-Reply-To: <20160822143637.GA18628@localhost> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org On 08/22/2016 07:36 AM, Bjorn Helgaas wrote: > Hi David & Omer, > > On Fri, Aug 19, 2016 at 03:32:12PM -0700, Omer Khaliq wrote: >> From: David Daney >> >> Some hardware presents an incorrect SR-IOV Function Dependency Link, >> add a function to allow this to be overridden in the PF driver for >> such devices. >> >> Signed-off-by: David Daney >> Signed-off-by: Omer Khaliq >> --- >> drivers/pci/iov.c | 14 ++++++++++++++ >> include/linux/pci.h | 1 + >> 2 files changed, 15 insertions(+) >> >> diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c >> index 2194b44..81f0672 100644 >> --- a/drivers/pci/iov.c >> +++ b/drivers/pci/iov.c >> @@ -640,6 +640,20 @@ int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn) >> EXPORT_SYMBOL_GPL(pci_enable_sriov); >> >> /** >> + * pci_sriov_fdl_override - fix incorrect Function Dependency Link >> + * @dev: the PCI device >> + * @fdl: the corrected Function Dependency Link value >> + * >> + * For hardware presenting an incorrect Function Dependency Link in >> + * the SR-IOV Extended Capability, allow a driver to override it. >> + */ >> +void pci_sriov_fdl_override(struct pci_dev *dev, u8 fdl) >> +{ >> + dev->sriov->link = fdl; >> +} >> +EXPORT_SYMBOL_GPL(pci_sriov_fdl_override); > > We usually use quirks to work around problems in config space. That's > a nice mechanism because we don't have to add new PCI core interfaces > and it makes it clear that we're working around a hardware problem. > > Can you use a quirk here? We allocate dev->sriov in the > pci_init_capabilities() path, so it looks like a pci_fixup_final quirk > should work. > The struct pci_sriov definition is private to drivers/pci, so in order to use a quirk to fix this, we would have to put it in drivers/pci/quirks.c. I was trying to keep this very device specific code in the driver, which requires an accessor to be able to manipulate the dev->sriov->link field. If you prefer a quirk in drivers/pci/quirks.c, we can certainly do that instead. Thanks for taking the time to look at this, David Daney >> + >> +/** >> * pci_disable_sriov - disable the SR-IOV capability >> * @dev: the PCI device >> */ >> diff --git a/include/linux/pci.h b/include/linux/pci.h >> index 2599a98..da8a5b3 100644 >> --- a/include/linux/pci.h >> +++ b/include/linux/pci.h >> @@ -1823,6 +1823,7 @@ int pci_num_vf(struct pci_dev *dev); >> int pci_vfs_assigned(struct pci_dev *dev); >> int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs); >> int pci_sriov_get_totalvfs(struct pci_dev *dev); >> +void pci_sriov_fdl_override(struct pci_dev *dev, u8 fdl); >> resource_size_t pci_iov_resource_size(struct pci_dev *dev, int resno); >> #else >> static inline int pci_iov_virtfn_bus(struct pci_dev *dev, int id) >> -- >> 1.9.1 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-pci" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html