[PATCH 05/10] PCI/ATS: Use FIELD_GET()

Bjorn Helgaas
2023-10-10T20:45:10Z

From: Bjorn Helgaas <bhelgaas@google.com>

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@google.com>
---
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));
}
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 */
--
2.34.1