On Tue, 15 May 2007, Andrew Morton wrote:
> On Tue, 15 May 2007 13:50:27 +0200
> "Peter Oruba" <[email protected]> wrote:
>
> > This patch set introduces a PCI-X / PCI-Express read byte count control
> > interface. Instead of letting every driver to directly read/write to PCI
> > config space for that, an interface is provided. The interface functions then
> > can be used for quirks since some PCI bridges require that read byte count
> > values are set by the BIOS and left unchanged by device drivers.
>
> Some of the patches were wordwrapped, which I fixed.
>
> The way we would merge a feature like this is
>
> - get maintainers to review-and-ack the change
This is definetly good cleanup, and I ACK the QLogic changes.
I do though have some questions on call prerequisites given the
driver-changes, most in the form of:
> diff -uprN -X linux-2.6.22-rc1.orig/Documentation/dontdiff
> linux-2.6.22-rc1.orig/drivers/infiniband/hw/mthca/mthca_main.c
> linux-2.6.22-rc1/drivers/infiniband/hw/mthca/mthca_main.c
> --- linux-2.6.22-rc1.orig/drivers/infiniband/hw/mthca/mthca_main.c 2007-05-14
> 11:29:29.358547000 +0200
> +++ linux-2.6.22-rc1/drivers/infiniband/hw/mthca/mthca_main.c 2007-05-15
> 10:55:24.954074000 +0200
> @@ -137,45 +137,27 @@ static const char mthca_version[] __devi
>
> static int mthca_tune_pci(struct mthca_dev *mdev)
> {
> - int cap;
> - u16 val;
> -
> if (!tune_pci)
> return 0;
>
> /* First try to max out Read Byte Count */
> - cap = pci_find_capability(mdev->pdev, PCI_CAP_ID_PCIX);
> - if (cap) {
> - if (pci_read_config_word(mdev->pdev, cap + PCI_X_CMD, &val)) {
> - mthca_err(mdev, "Couldn't read PCI-X command register, "
> - "aborting.\n");
> - return -ENODEV;
> - }
> - val = (val & ~PCI_X_CMD_MAX_READ) | (3 << 2);
> - if (pci_write_config_word(mdev->pdev, cap + PCI_X_CMD, val)) {
> - mthca_err(mdev, "Couldn't write PCI-X command register, "
> - "aborting.\n");
> + if (pci_find_capability(mdev->pdev, PCI_CAP_ID_PCIX)) {
> + if (pcix_set_mmrbc(mdev->pdev, pcix_get_max_mmrbc(mdev->pdev))) {
> + mthca_err(mdev, "Couldn't set PCI-X max read count, "
> + "aborting.\n");
...
> - cap = pci_find_capability(mdev->pdev, PCI_CAP_ID_EXP);
> - if (cap) {
> - if (pci_read_config_word(mdev->pdev, cap + PCI_EXP_DEVCTL, &val)) {
> - mthca_err(mdev, "Couldn't read PCI Express device control "
> - "register, aborting.\n");
> - return -ENODEV;
> - }
> - val = (val & ~PCI_EXP_DEVCTL_READRQ) | (5 << 12);
> - if (pci_write_config_word(mdev->pdev, cap + PCI_EXP_DEVCTL, val)) {
> - mthca_err(mdev, "Couldn't write PCI Express device control "
> - "register, aborting.\n");
> + if (pci_find_capability(mdev->pdev, PCI_CAP_ID_EXP)) {
> + if (pcie_set_readrq(mdev->pdev, 4096)) {
> + mthca_err(mdev, "Couldn't write PCI Express read request, "
> + "aborting.\n");
In general, if PCI-[Xe] capability structure exists do set-
mmrbc()/readrq(), yet each of those pre-condition checks are already
present in the pcix_set_mmrbc() and pcie_set_readrq().
At least for the qla2xxx case, the patch could easily distill down from:
...
/* PCIe -- adjust Maximum Read Request Size (2048). */
pcie_dctl_reg = pci_find_capability(ha->pdev, PCI_CAP_ID_EXP);
if (pcie_dctl_reg)
if (pcie_set_readrq(ha->pdev, 2048))
DEBUG2(printk("Couldn't write PCI Express read request\n"));
to:
...
pcie_set_readrq(ha->pdev, 2048);
Whatever the decision, I can fold this into my next patchset for
qla2xxx and submit.
-
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