On Tue, 10 Oct 2023 15:44:31 -0500 Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > > Use FIELD_GET() to remove dependences on the field position, i.e., the > shift value. No functional change intended. > > Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> One trivial comment inline. Either way. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > --- > drivers/pci/ats.c | 7 ++----- > include/uapi/linux/pci_regs.h | 1 + > 2 files changed, 3 insertions(+), 5 deletions(-) > > diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c > index f9cc2e10b676..c570892b2090 100644 > --- a/drivers/pci/ats.c > +++ b/drivers/pci/ats.c > @@ -9,6 +9,7 @@ > * Copyright (C) 2011 Advanced Micro Devices, > */ > > +#include <linux/bitfield.h> > #include <linux/export.h> > #include <linux/pci-ats.h> > #include <linux/pci.h> > @@ -480,8 +481,6 @@ int pci_pasid_features(struct pci_dev *pdev) > } > EXPORT_SYMBOL_GPL(pci_pasid_features); > > -#define PASID_NUMBER_SHIFT 8 > -#define PASID_NUMBER_MASK (0x1f << PASID_NUMBER_SHIFT) > /** > * pci_max_pasids - Get maximum number of PASIDs supported by device > * @pdev: PCI device structure > @@ -503,9 +502,7 @@ int pci_max_pasids(struct pci_dev *pdev) > > pci_read_config_word(pdev, pasid + PCI_PASID_CAP, &supported); > > - supported = (supported & PASID_NUMBER_MASK) >> PASID_NUMBER_SHIFT; > - > - return (1 << supported); > + return (1 << FIELD_GET(PCI_PASID_CAP_WIDTH, supported)); Could drop the bonus set of brackets.. > } > EXPORT_SYMBOL_GPL(pci_max_pasids); > #endif /* CONFIG_PCI_PASID */ > diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h > index 6af1f8d53e97..833e5fb40ea5 100644 > --- a/include/uapi/linux/pci_regs.h > +++ b/include/uapi/linux/pci_regs.h > @@ -932,6 +932,7 @@ > #define PCI_PASID_CAP 0x04 /* PASID feature register */ > #define PCI_PASID_CAP_EXEC 0x0002 /* Exec permissions Supported */ > #define PCI_PASID_CAP_PRIV 0x0004 /* Privilege Mode Supported */ > +#define PCI_PASID_CAP_WIDTH 0x1f00 > #define PCI_PASID_CTRL 0x06 /* PASID control register */ > #define PCI_PASID_CTRL_ENABLE 0x0001 /* Enable bit */ > #define PCI_PASID_CTRL_EXEC 0x0002 /* Exec permissions Enable */
