From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.codeaurora.org ([198.145.29.96]:48396 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752395AbcKJSir (ORCPT ); Thu, 10 Nov 2016 13:38:47 -0500 Subject: Re: [PATCH V2 5/5] PCI: handle CRS returned by device after FLR To: linux-pci@vger.kernel.org, timur@codeaurora.org, cov@codeaurora.org, alex.williamson@redhat.com, vikrams@codeaurora.org References: <1474056395-21843-1-git-send-email-okaya@codeaurora.org> <1474056395-21843-6-git-send-email-okaya@codeaurora.org> Cc: linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org From: Sinan Kaya Message-ID: Date: Thu, 10 Nov 2016 13:38:43 -0500 MIME-Version: 1.0 In-Reply-To: <1474056395-21843-6-git-send-email-okaya@codeaurora.org> Content-Type: text/plain; charset=windows-1252 Sender: linux-pci-owner@vger.kernel.org List-ID: On 9/16/2016 4:06 PM, Sinan Kaya wrote: > An endpoint is allowed to issue CRS following an FLR request to indicate > that it is not ready to accept new requests. Changing the polling mechanism > in FLR wait function to go read the vendor ID instead of the command/status > register. A CRS indication will only be given if the address to be read is > vendor ID. > > Signed-off-by: Sinan Kaya > --- > drivers/pci/pci.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index e913467..1def11e 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -3729,7 +3729,8 @@ static void pci_flr_wait(struct pci_dev *dev) > > do { > msleep(100); > - pci_read_config_dword(dev, PCI_COMMAND, &id); > + pci_bus_read_dev_vendor_id(dev->bus, dev->devfn, &id, > + 60 * 1000); We found out during Mellanox CX3 testing that the card returns the vendor ID earlier during FLR while other cards are OK with this implementaiton. I think we need both of the reads to support the CRS for the endpoints and also the command id register read to make sure endpoint init is complete. > } while (i++ < 10 && id == ~0); > > if (id == ~0) > -- Sinan Kaya Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.