cxgb4: Prefer pcie_capability_read_word()

Commit 8c0d3a02c130 ("PCI: Add accessors for PCI Express Capability")
added accessors for the PCI Express Capability so that drivers didn't
need to be aware of differences between v1 and v2 of the PCI
Express Capability.

Replace pci_read_config_word() and pci_write_config_word() calls with
pcie_capability_read_word() and pcie_capability_write_word().

Signed-off-by: Frederick Lawler <fred@fredlawl.com>
---
 drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c | 6 ++----
 drivers/net/ethernet/chelsio/cxgb4/t4_hw.c      | 9 +++------
 2 files changed, 5 insertions(+), 10 deletions(-)

On Wed, Jul 17, 2019 at 9:08 PM Frederick Lawler <fred@fredlawl.com> wrote:
>
> Commit 8c0d3a02c130 ("PCI: Add accessors for PCI Express Capability")
> added accessors for the PCI Express Capability so that drivers didn't
> need to be aware of differences between v1 and v2 of the PCI
> Express Capability.
>
> Replace pci_read_config_word() and pci_write_config_word() calls with
> pcie_capability_read_word() and pcie_capability_write_word().
>
> Signed-off-by: Frederick Lawler <fred@fredlawl.com>

Nice job on all these patches!  These all help avoid errors and
identify possibilities for refactoring.

If there were a cover letter for the series, I would have replied to
that, but for all of them:

Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>

If you post the series again for any reason, you can add that.
Otherwise, whoever applies them can add my reviewed-by.

> ---
>  drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c | 6 ++----
>  drivers/net/ethernet/chelsio/cxgb4/t4_hw.c      | 9 +++------
>  2 files changed, 5 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
> index 715e4edcf4a2..98ff71434673 100644
> --- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
> +++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
> @@ -5441,7 +5441,6 @@ static int cxgb4_iov_configure(struct pci_dev *pdev, int num_vfs)
>                 char name[IFNAMSIZ];
>                 u32 devcap2;
>                 u16 flags;
> -               int pos;
>
>                 /* If we want to instantiate Virtual Functions, then our
>                  * parent bridge's PCI-E needs to support Alternative Routing
> @@ -5449,9 +5448,8 @@ static int cxgb4_iov_configure(struct pci_dev *pdev, int num_vfs)
>                  * and above.
>                  */
>                 pbridge = pdev->bus->self;
> -               pos = pci_find_capability(pbridge, PCI_CAP_ID_EXP);
> -               pci_read_config_word(pbridge, pos + PCI_EXP_FLAGS, &flags);
> -               pci_read_config_dword(pbridge, pos + PCI_EXP_DEVCAP2, &devcap2);
> +               pcie_capability_read_word(pbridge, PCI_EXP_FLAGS, &flags);
> +               pcie_capability_read_dword(pbridge, PCI_EXP_DEVCAP2, &devcap2);
>
>                 if ((flags & PCI_EXP_FLAGS_VERS) < 2 ||
>                     !(devcap2 & PCI_EXP_DEVCAP2_ARI)) {
> diff --git a/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c b/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c
> index f9b70be59792..346d7b59c50b 100644
> --- a/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c
> +++ b/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c
> @@ -7267,7 +7267,6 @@ int t4_fixup_host_params(struct adapter *adap, unsigned int page_size,
>         } else {
>                 unsigned int pack_align;
>                 unsigned int ingpad, ingpack;
> -               unsigned int pcie_cap;
>
>                 /* T5 introduced the separation of the Free List Padding and
>                  * Packing Boundaries.  Thus, we can select a smaller Padding
> @@ -7292,8 +7291,7 @@ int t4_fixup_host_params(struct adapter *adap, unsigned int page_size,
>                  * multiple of the Maximum Payload Size.
>                  */
>                 pack_align = fl_align;
> -               pcie_cap = pci_find_capability(adap->pdev, PCI_CAP_ID_EXP);
> -               if (pcie_cap) {
> +               if (pci_is_pcie(adap->pdev)) {
>                         unsigned int mps, mps_log;
>                         u16 devctl;
>
> @@ -7301,9 +7299,8 @@ int t4_fixup_host_params(struct adapter *adap, unsigned int page_size,
>                          * [bits 7:5] encodes sizes as powers of 2 starting at
>                          * 128 bytes.
>                          */
> -                       pci_read_config_word(adap->pdev,
> -                                            pcie_cap + PCI_EXP_DEVCTL,
> -                                            &devctl);
> +                       pcie_capability_read_word(adap->pdev, PCI_EXP_DEVCTL,
> +                                                 &devctl);
>                         mps_log = ((devctl & PCI_EXP_DEVCTL_PAYLOAD) >> 5) + 7;
>                         mps = 1 << mps_log;
>                         if (mps > pack_align)
> --
> 2.17.1
>

From: Frederick Lawler <fred@fredlawl.com>
Date: Wed, 17 Jul 2019 21:07:36 -0500

> Commit 8c0d3a02c130 ("PCI: Add accessors for PCI Express Capability")
> added accessors for the PCI Express Capability so that drivers didn't
> need to be aware of differences between v1 and v2 of the PCI
> Express Capability.
> 
> Replace pci_read_config_word() and pci_write_config_word() calls with
> pcie_capability_read_word() and pcie_capability_write_word().
> 
> Signed-off-by: Frederick Lawler <fred@fredlawl.com>

Applied.