netdev - [PATCH v2 1/3] PCI: Disable parity checking if broken

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Message-ID: <ee1e400f-33b7-865c-2f6a-e77581e11f3f@gmail.com>
Date:   Wed, 6 Jan 2021 12:03:00 +0100
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Bjorn Helgaas <bhelgaas@...gle.com>,
        Russell King - ARM Linux <linux@...linux.org.uk>,
        Realtek linux nic maintainers <nic_swsd@...ltek.com>,
        David Miller <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Cc:     "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: [PATCH v2 1/3] PCI: Disable parity checking if broken_parity is set

If we know that a device has broken parity checking, then disable it.
This avoids quirks like in r8169 where on the first parity error
interrupt parity checking will be disabled if broken_parity_status
is set. Make pci_quirk_broken_parity() public so that it can be used
by platform code, e.g. for Thecus N2100.

Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
Reviewed-by: Leon Romanovsky <leonro@...dia.com>
---
 drivers/pci/quirks.c | 17 +++++++++++------
 include/linux/pci.h  |  2 ++
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 653660e3b..ab54e26b8 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -205,17 +205,22 @@ static void quirk_mmio_always_on(struct pci_dev *dev)
 DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_ANY_ID, PCI_ANY_ID,
 				PCI_CLASS_BRIDGE_HOST, 8, quirk_mmio_always_on);
 
+void pci_quirk_broken_parity(struct pci_dev *dev)
+{
+	u16 cmd;
+
+	dev->broken_parity_status = 1;	/* This device gives false positives */
+	pci_read_config_word(dev, PCI_COMMAND, &cmd);
+	pci_write_config_word(dev, PCI_COMMAND, cmd & ~PCI_COMMAND_PARITY);
+}
+
 /*
  * The Mellanox Tavor device gives false positive parity errors.  Mark this
  * device with a broken_parity_status to allow PCI scanning code to "skip"
  * this now blacklisted device.
  */
-static void quirk_mellanox_tavor(struct pci_dev *dev)
-{
-	dev->broken_parity_status = 1;	/* This device gives false positives */
-}
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_MELLANOX, PCI_DEVICE_ID_MELLANOX_TAVOR, quirk_mellanox_tavor);
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_MELLANOX, PCI_DEVICE_ID_MELLANOX_TAVOR_BRIDGE, quirk_mellanox_tavor);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_MELLANOX, PCI_DEVICE_ID_MELLANOX_TAVOR, pci_quirk_broken_parity);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_MELLANOX, PCI_DEVICE_ID_MELLANOX_TAVOR_BRIDGE, pci_quirk_broken_parity);
 
 /*
  * Deal with broken BIOSes that neglect to enable passive release,
diff --git a/include/linux/pci.h b/include/linux/pci.h
index b32126d26..161dcc474 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1916,6 +1916,8 @@ enum pci_fixup_pass {
 	pci_fixup_suspend_late,	/* pci_device_suspend_late() */
 };
 
+void pci_quirk_broken_parity(struct pci_dev *dev);
+
 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
 #define __DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class,	\
 				    class_shift, hook)			\
-- 
2.30.0