Re: [PATCH 08/10] PCI/PTM: Use FIELD_GET()

Ilpo Järvinen
2023-10-11T11:16:29Z

On Tue, 10 Oct 2023, Bjorn Helgaas wrote:

> 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>

You seem to be using FIELD_PREP() too below.

> ---
> drivers/pci/pcie/ptm.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/pcie/ptm.c b/drivers/pci/pcie/ptm.c
> index b4e5f553467c..7cfb6c0d5dcb 100644
> --- a/drivers/pci/pcie/ptm.c
> +++ b/drivers/pci/pcie/ptm.c
> @@ -4,6 +4,7 @@
> * Copyright (c) 2016, Intel Corporation.
> */
>
> +#include <linux/bitfield.h>
> #include <linux/module.h>
> #include <linux/init.h>
> #include <linux/pci.h>
> @@ -53,7 +54,7 @@ void pci_ptm_init(struct pci_dev *dev)
> pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_PTM, sizeof(u32));
>
> pci_read_config_dword(dev, ptm + PCI_PTM_CAP, &cap);
> - dev->ptm_granularity = (cap & PCI_PTM_GRANULARITY_MASK) >> 8;
> + dev->ptm_granularity = FIELD_GET(PCI_PTM_GRANULARITY_MASK, cap);
>
> /*
> * Per the spec recommendation (PCIe r6.0, sec 7.9.15.3), select the
> @@ -146,7 +147,7 @@ static int __pci_enable_ptm(struct pci_dev *dev)
>
> ctrl |= PCI_PTM_CTRL_ENABLE;
> ctrl &= ~PCI_PTM_GRANULARITY_MASK;
> - ctrl |= dev->ptm_granularity << 8;
> + ctrl |= FIELD_PREP(PCI_PTM_GRANULARITY_MASK, dev->ptm_granularity);
> if (dev->ptm_root)
> ctrl |= PCI_PTM_CTRL_ROOT;
>
>

--
i.