Re: [PATCH v4 05/10] PCI: Add pci_status_get_and_clear_errors
From: Bjorn Helgaas <helgaas@kernel.org>
Date: 2020-03-04 13:43:22
Also in:
alsa-devel, linux-pci, lkml
On Sat, Feb 29, 2020 at 11:24:23PM +0100, Heiner Kallweit wrote:
Several drivers use the following code sequence: 1. Read PCI_STATUS 2. Mask out non-error bits 3. Action based on error bits set 4. Write back set error bits to clear them As this is a repeated pattern, add a helper to the PCI core. Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> Nit: if you have any reason to revise this, I would prefer "pci_status_get_and_clear_errors()" (with parens) in the subject.
quoted hunk ↗ jump to hunk
--- v4: - improve commit description --- drivers/pci/pci.c | 23 +++++++++++++++++++++++ include/linux/pci.h | 1 + 2 files changed, 24 insertions(+)diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index d828ca835..c16b0ba2a 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c@@ -173,6 +173,29 @@ unsigned char pci_bus_max_busnr(struct pci_bus *bus) } EXPORT_SYMBOL_GPL(pci_bus_max_busnr); +/** + * pci_status_get_and_clear_errors - return and clear error bits in PCI_STATUS + * @pdev: the PCI device + * + * Returns error bits set in PCI_STATUS and clears them. + */ +int pci_status_get_and_clear_errors(struct pci_dev *pdev) +{ + u16 status; + int ret; + + ret = pci_read_config_word(pdev, PCI_STATUS, &status); + if (ret != PCIBIOS_SUCCESSFUL) + return -EIO; + + status &= PCI_STATUS_ERROR_BITS; + if (status) + pci_write_config_word(pdev, PCI_STATUS, status); + + return status; +} +EXPORT_SYMBOL_GPL(pci_status_get_and_clear_errors); + #ifdef CONFIG_HAS_IOMEM void __iomem *pci_ioremap_bar(struct pci_dev *pdev, int bar) {diff --git a/include/linux/pci.h b/include/linux/pci.h index 101d71e0a..7beaf51e9 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h@@ -1210,6 +1210,7 @@ int pci_select_bars(struct pci_dev *dev, unsigned long flags); bool pci_device_is_present(struct pci_dev *pdev); void pci_ignore_hotplug(struct pci_dev *dev); struct pci_dev *pci_real_dma_dev(struct pci_dev *dev); +int pci_status_get_and_clear_errors(struct pci_dev *pdev); int __printf(6, 7) pci_request_irq(struct pci_dev *dev, unsigned int nr, irq_handler_t handler, irq_handler_t thread_fn, void *dev_id,-- 2.25.1