PCI: Add pci_disable_parity()

Add pci_disable_parity() to disable reporting of parity errors for a
device by clearing PCI_COMMAND_PARITY.

The device will still set PCI_STATUS_DETECTED_PARITY when it detects
a parity error or receives a Poisoned TLP, but it will not set
PCI_STATUS_PARITY, which means it will not assert PERR#
(conventional PCI) or report Poisoned TLPs (PCIe).

Based-on: https://lore.kernel.org/linux-arm-kernel/d375987c-ea4f-dd98-4ef8-99b2fbfe7c33@gmail.com/
Based-on-patch-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/20210330174318.1289680-2-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 16a17215f633ddc40d87faa4329bdfb20a7e2ed5..b1845e5e5c8f81a0f6c5396280bb6cd59e4bc3d5 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4453,6 +4453,23 @@ void pci_clear_mwi(struct pci_dev *dev)
 }
 EXPORT_SYMBOL(pci_clear_mwi);
 
+/**
+ * pci_disable_parity - disable parity checking for device
+ * @dev: the PCI device to operate on
+ *
+ * Disable parity checking for device @dev
+ */
+void pci_disable_parity(struct pci_dev *dev)
+{
+       u16 cmd;
+
+       pci_read_config_word(dev, PCI_COMMAND, &cmd);
+       if (cmd & PCI_COMMAND_PARITY) {
+               cmd &= ~PCI_COMMAND_PARITY;
+               pci_write_config_word(dev, PCI_COMMAND, cmd);
+       }
+}
+
 /**
  * pci_intx - enables/disables PCI INTx for device dev
  * @pdev: the PCI device to operate on

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 86c799c97b7796665524666dc4a73f12ab81cbb3..4eaa773115daab17b553f6927861ce92bc3b3197 100644 (file)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1201,6 +1201,7 @@ int __must_check pci_set_mwi(struct pci_dev *dev);
 int __must_check pcim_set_mwi(struct pci_dev *dev);
 int pci_try_set_mwi(struct pci_dev *dev);
 void pci_clear_mwi(struct pci_dev *dev);
+void pci_disable_parity(struct pci_dev *dev);
 void pci_intx(struct pci_dev *dev, int enable);
 bool pci_check_and_mask_intx(struct pci_dev *dev);
 bool pci_check_and_unmask_intx(struct pci_dev *dev);