Re: [RFC PATCH 04/14] PCI: refine and move pcie_cap_has_*() macros to include/linux/pci.h

[Bjorn Helgaas <bhelgaas@google.com>]

On Tue, Jul 10, 2012 at 9:54 AM, Jiang Liu <liuj97@gmail.com> wrote:
> From: Jiang Liu <jiang.liu@huawei.com>
>
> Move pcie_cap_has_*() macros to include/linux/pci.h, so they can be shared.
> Since pcie_flags was introduced, rework these macros to take a struct pci_dev *
> and use pcie_flags insead of type and flags.
>
> Signed-off-by: Jiang Liu <liuj97@gmail.com>
> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
> ---
>  drivers/pci/pci.c   |   50 ++++++++++++--------------------------------------
>  include/linux/pci.h |   43 +++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 55 insertions(+), 38 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 28eb55b..4c6ab70 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -272,15 +272,11 @@ int pci_bus_find_capability(struct pci_bus *bus, unsigned int devfn, int cap)
>   */
>  static int pci_pcie_cap2(struct pci_dev *dev)
>  {
> -       u16 flags;
>         int pos;
>
>         pos = pci_pcie_cap(dev);
> -       if (pos) {
> -               pci_read_config_word(dev, pos + PCI_EXP_FLAGS, &flags);
> -               if ((flags & PCI_EXP_FLAGS_VERS) < 2)
> -                       pos = 0;
> -       }
> +       if (pos && !pci_pcie_cap_has_cap2(dev))
> +               pos = 0;
>
>         return pos;
>  }
> @@ -854,21 +850,6 @@ EXPORT_SYMBOL(pci_choose_state);
>
>  #define PCI_EXP_SAVE_REGS      7
>
> -#define pcie_cap_has_devctl(type, flags)       1
> -#define pcie_cap_has_lnkctl(type, flags)               \
> -               ((flags & PCI_EXP_FLAGS_VERS) > 1 ||    \
> -                (type == PCI_EXP_TYPE_ROOT_PORT ||     \
> -                 type == PCI_EXP_TYPE_ENDPOINT ||      \
> -                 type == PCI_EXP_TYPE_LEG_END))
> -#define pcie_cap_has_sltctl(type, flags)               \
> -               ((flags & PCI_EXP_FLAGS_VERS) > 1 ||    \
> -                ((type == PCI_EXP_TYPE_ROOT_PORT) ||   \
> -                 (type == PCI_EXP_TYPE_DOWNSTREAM &&   \
> -                  (flags & PCI_EXP_FLAGS_SLOT))))
> -#define pcie_cap_has_rtctl(type, flags)                        \
> -               ((flags & PCI_EXP_FLAGS_VERS) > 1 ||    \
> -                (type == PCI_EXP_TYPE_ROOT_PORT ||     \
> -                 type == PCI_EXP_TYPE_RC_EC))
>
>  static struct pci_cap_saved_state *pci_find_saved_cap(
>         struct pci_dev *pci_dev, char cap)
> @@ -885,10 +866,9 @@ static struct pci_cap_saved_state *pci_find_saved_cap(
>
>  static int pci_save_pcie_state(struct pci_dev *dev)
>  {
> -       int type, pos, i = 0;
> +       int pos, i = 0;
>         struct pci_cap_saved_state *save_state;
>         u16 *cap;
> -       u16 flags;
>
>         pos = pci_pcie_cap(dev);
>         if (!pos)
> @@ -901,16 +881,14 @@ static int pci_save_pcie_state(struct pci_dev *dev)
>         }
>         cap = (u16 *)&save_state->cap.data[0];
>
> -       pci_read_config_word(dev, pos + PCI_EXP_FLAGS, &flags);
>
> -       type = pci_pcie_type(dev);
> -       if (pcie_cap_has_devctl(type, flags))
> +       if (pci_pcie_cap_has_devctl(dev))
>                 pci_read_config_word(dev, pos + PCI_EXP_DEVCTL, &cap[i++]);
> -       if (pcie_cap_has_lnkctl(type, flags))
> +       if (pci_pcie_cap_has_lnkctl(dev))
>                 pci_read_config_word(dev, pos + PCI_EXP_LNKCTL, &cap[i++]);
> -       if (pcie_cap_has_sltctl(type, flags))
> +       if (pci_pcie_cap_has_sltctl(dev))
>                 pci_read_config_word(dev, pos + PCI_EXP_SLTCTL, &cap[i++]);
> -       if (pcie_cap_has_rtctl(type, flags))
> +       if (pci_pcie_cap_has_rtctl(dev))
>                 pci_read_config_word(dev, pos + PCI_EXP_RTCTL, &cap[i++]);
>
>         pos = pci_pcie_cap2(dev);
> @@ -925,10 +903,9 @@ static int pci_save_pcie_state(struct pci_dev *dev)
>
>  static void pci_restore_pcie_state(struct pci_dev *dev)
>  {
> -       int i = 0, pos, type;
> +       int i = 0, pos;
>         struct pci_cap_saved_state *save_state;
>         u16 *cap;
> -       u16 flags;
>
>         save_state = pci_find_saved_cap(dev, PCI_CAP_ID_EXP);
>         pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
> @@ -936,16 +913,13 @@ static void pci_restore_pcie_state(struct pci_dev *dev)
>                 return;
>         cap = (u16 *)&save_state->cap.data[0];
>
> -       pci_read_config_word(dev, pos + PCI_EXP_FLAGS, &flags);
> -
> -       type = pci_pcie_type(dev);
> -       if (pcie_cap_has_devctl(type, flags))
> +       if (pci_pcie_cap_has_devctl(dev))
>                 pci_write_config_word(dev, pos + PCI_EXP_DEVCTL, cap[i++]);
> -       if (pcie_cap_has_lnkctl(type, flags))
> +       if (pci_pcie_cap_has_lnkctl(dev))
>                 pci_write_config_word(dev, pos + PCI_EXP_LNKCTL, cap[i++]);
> -       if (pcie_cap_has_sltctl(type, flags))
> +       if (pci_pcie_cap_has_sltctl(dev))
>                 pci_write_config_word(dev, pos + PCI_EXP_SLTCTL, cap[i++]);
> -       if (pcie_cap_has_rtctl(type, flags))
> +       if (pci_pcie_cap_has_rtctl(dev))
>                 pci_write_config_word(dev, pos + PCI_EXP_RTCTL, cap[i++]);
>
>         pos = pci_pcie_cap2(dev);
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 1837354..346b2d9 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1659,6 +1659,49 @@ static inline int pci_pcie_type(const struct pci_dev *dev)
>         return (dev->pcie_flags & PCI_EXP_FLAGS_TYPE) >> 4;
>  }
>
> +static inline int pci_pcie_cap_version(const struct pci_dev *pdev)
> +{
> +       return pdev->pcie_flags & PCI_EXP_FLAGS_VERS;
> +}
> +
> +static inline int pci_pcie_cap_has_cap2(const struct pci_dev *pdev)
> +{
> +       return pci_pcie_cap_version(pdev) > 1;
> +}

Do we need these (pci_pcie_cap_version() and pci_pcie_cap_has_cap2())
anywhere other than maybe in pci/access.c?  I hope not.

> +
> +static inline bool pci_pcie_cap_has_devctl(const struct pci_dev *pdev)
> +{
> +       return true;
> +}
> +
> +static inline bool pci_pcie_cap_has_lnkctl(const struct pci_dev *pdev)
> +{
> +       int type = pci_pcie_type(pdev);
> +
> +       return pci_pcie_cap_version(pdev) > 1 ||
> +              type == PCI_EXP_TYPE_ROOT_PORT ||
> +              type == PCI_EXP_TYPE_ENDPOINT ||
> +              type == PCI_EXP_TYPE_LEG_END;
> +}
> +
> +static inline bool pci_pcie_cap_has_sltctl(const struct pci_dev *pdev)
> +{
> +       int type = pci_pcie_type(pdev);
> +
> +       return pci_pcie_cap_version(pdev) > 1 ||
> +              type == PCI_EXP_TYPE_ROOT_PORT ||
> +              (type == PCI_EXP_TYPE_DOWNSTREAM &&
> +               pdev->pcie_flags & PCI_EXP_FLAGS_SLOT);
> +}
> +
> +static inline bool pci_pcie_cap_has_rtctl(const struct pci_dev *pdev)
> +{
> +       int type = pci_pcie_type(pdev);
> +
> +       return pci_pcie_cap_version(pdev) > 1 ||
> +              type == PCI_EXP_TYPE_ROOT_PORT ||
> +              type == PCI_EXP_TYPE_RC_EC;
> +}

I hope these are used only in pci_pcie_cap_read/write(), so maybe they
could just be moved to access.c along with them.  Maybe you can just
*add* definitions to pci/access.c (leaving pci/pci.c alone).  Then
you'd only have to touch the save/restore_pcie_state() functions once.

>  void pci_request_acs(void);
>  bool pci_acs_enabled(struct pci_dev *pdev, u16 acs_flags);
> --
> 1.7.9.5
>