On Thu, 15 Feb 2024, Ilpo Järvinen wrote:
> Convert open coded RMW accesses for LNKCTL2 to use
> pcie_capability_clear_and_set_word() which makes its easier to
> understand what the code tries to do.
>
> LNKCTL2 is not really owned by any driver because it is a collection of
> control bits that PCI core might need to touch. RMW accessors already
> have support for proper locking for a selected set of registers
> (LNKCTL2 is not yet among them but likely will be in the future) to
> avoid losing concurrent updates.
>
> Suggested-by: Lukas Wunner <lukas@xxxxxxxxx>
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
> Reviewed-by: Dean Luick <dean.luick@xxxxxxxxxxxxxxxxxxxx>
I found out from Linux RDMA and InfiniBand patchwork that this patch had
been silently closed as "Not Applicable". Is there some reason for that?
I was sending this change independently out (among 2 similar ones that
already got applied) so I wouldn't need to keep carrying it within my PCIe
bandwidth controller series. It seemed useful enough as cleanups to stand
on its own legs w/o requiring it to be part of PCIe bw controller series.
Should I resend the patch or do RDMA/IB maintainers prefer it to remain
as a part of PCIe BW controller series?
--
i.
> ---
> drivers/infiniband/hw/hfi1/pcie.c | 30 ++++++++----------------------
> 1 file changed, 8 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/infiniband/hw/hfi1/pcie.c b/drivers/infiniband/hw/hfi1/pcie.c
> index 119ec2f1382b..7133964749f8 100644
> --- a/drivers/infiniband/hw/hfi1/pcie.c
> +++ b/drivers/infiniband/hw/hfi1/pcie.c
> @@ -1207,14 +1207,11 @@ int do_pcie_gen3_transition(struct hfi1_devdata *dd)
> (u32)lnkctl2);
> /* only write to parent if target is not as high as ours */
> if ((lnkctl2 & PCI_EXP_LNKCTL2_TLS) < target_vector) {
> - lnkctl2 &= ~PCI_EXP_LNKCTL2_TLS;
> - lnkctl2 |= target_vector;
> - dd_dev_info(dd, "%s: ..new link control2: 0x%x\n", __func__,
> - (u32)lnkctl2);
> - ret = pcie_capability_write_word(parent,
> - PCI_EXP_LNKCTL2, lnkctl2);
> + ret = pcie_capability_clear_and_set_word(parent, PCI_EXP_LNKCTL2,
> + PCI_EXP_LNKCTL2_TLS,
> + target_vector);
> if (ret) {
> - dd_dev_err(dd, "Unable to write to PCI config\n");
> + dd_dev_err(dd, "Unable to change parent PCI target speed\n");
> return_error = 1;
> goto done;
> }
> @@ -1223,22 +1220,11 @@ int do_pcie_gen3_transition(struct hfi1_devdata *dd)
> }
>
> dd_dev_info(dd, "%s: setting target link speed\n", __func__);
> - ret = pcie_capability_read_word(dd->pcidev, PCI_EXP_LNKCTL2, &lnkctl2);
> + ret = pcie_capability_clear_and_set_word(dd->pcidev, PCI_EXP_LNKCTL2,
> + PCI_EXP_LNKCTL2_TLS,
> + target_vector);
> if (ret) {
> - dd_dev_err(dd, "Unable to read from PCI config\n");
> - return_error = 1;
> - goto done;
> - }
> -
> - dd_dev_info(dd, "%s: ..old link control2: 0x%x\n", __func__,
> - (u32)lnkctl2);
> - lnkctl2 &= ~PCI_EXP_LNKCTL2_TLS;
> - lnkctl2 |= target_vector;
> - dd_dev_info(dd, "%s: ..new link control2: 0x%x\n", __func__,
> - (u32)lnkctl2);
> - ret = pcie_capability_write_word(dd->pcidev, PCI_EXP_LNKCTL2, lnkctl2);
> - if (ret) {
> - dd_dev_err(dd, "Unable to write to PCI config\n");
> + dd_dev_err(dd, "Unable to change device PCI target speed\n");
> return_error = 1;
> goto done;
> }
>
