IB/qib: Use pcie_set_mps() and pcie_get_mps() to simplify code

Refactor qib_tune_pcie_caps().  Use pcie_get_mps(), pcie_set_mps(),
pcie_get_readrq(), and pcie_set_readrq() to simplify the code.  The PCI
core caches the "PCIe Max Payload Size Supported" in pci_dev->pcie_mpss,
so use that instead of pcie_capability_read_word().  Remove the unused
val2fld() and fld2val().

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Mike Marciniszyn <mike.marciniszyn@intel.com>

diff --git a/drivers/infiniband/hw/qib/qib_pcie.c b/drivers/infiniband/hw/qib/qib_pcie.c
index 45e55ff..24973c8 100644 (file)
--- a/drivers/infiniband/hw/qib/qib_pcie.c
+++ b/drivers/infiniband/hw/qib/qib_pcie.c
@@ -476,30 +476,6 @@ void qib_pcie_reenable(struct qib_devdata *dd, u16 cmd, u8 iline, u8 cline)
                        "pci_enable_device failed after reset: %d\n", r);
 }
 
-/* code to adjust PCIe capabilities. */
-
-static int fld2val(int wd, int mask)
-{
-       int lsbmask;
-
-       if (!mask)
-               return 0;
-       wd &= mask;
-       lsbmask = mask ^ (mask & (mask - 1));
-       wd /= lsbmask;
-       return wd;
-}
-
-static int val2fld(int wd, int mask)
-{
-       int lsbmask;
-
-       if (!mask)
-               return 0;
-       lsbmask = mask ^ (mask & (mask - 1));
-       wd *= lsbmask;
-       return wd;
-}
 
 static int qib_pcie_coalesce;
 module_param_named(pcie_coalesce, qib_pcie_coalesce, int, S_IRUGO);
@@ -584,9 +560,8 @@ static int qib_tune_pcie_caps(struct qib_devdata *dd)
 {
        int ret = 1; /* Assume the worst */
        struct pci_dev *parent;
-       u16 pcaps, pctl, ecaps, ectl;
-       int rc_sup, ep_sup;
-       int rc_cur, ep_cur;
+       u16 rc_mpss, rc_mps, ep_mpss, ep_mps;
+       u16 rc_mrrs, ep_mrrs, max_mrrs;
 
        /* Find out supported and configured values for parent (root) */
        parent = dd->pcidev->bus->self;
@@ -597,38 +572,29 @@ static int qib_tune_pcie_caps(struct qib_devdata *dd)
 
        if (!pci_is_pcie(parent) || !pci_is_pcie(dd->pcidev))
                goto bail;
-       pcie_capability_read_word(parent, PCI_EXP_DEVCAP, &pcaps);
-       pcie_capability_read_word(parent, PCI_EXP_DEVCTL, &pctl);
+       rc_mpss = parent->pcie_mpss;
+       rc_mps = ffs(pcie_get_mps(parent)) - 8;
        /* Find out supported and configured values for endpoint (us) */
-       pcie_capability_read_word(dd->pcidev, PCI_EXP_DEVCAP, &ecaps);
-       pcie_capability_read_word(dd->pcidev, PCI_EXP_DEVCTL, &ectl);
+       ep_mpss = dd->pcidev->pcie_mpss;
+       ep_mps = ffs(pcie_get_mps(dd->pcidev)) - 8;
 
        ret = 0;
        /* Find max payload supported by root, endpoint */
-       rc_sup = fld2val(pcaps, PCI_EXP_DEVCAP_PAYLOAD);
-       ep_sup = fld2val(ecaps, PCI_EXP_DEVCAP_PAYLOAD);
-       if (rc_sup > ep_sup)
-               rc_sup = ep_sup;
-
-       rc_cur = fld2val(pctl, PCI_EXP_DEVCTL_PAYLOAD);
-       ep_cur = fld2val(ectl, PCI_EXP_DEVCTL_PAYLOAD);
+       if (rc_mpss > ep_mpss)
+               rc_mpss = ep_mpss;
 
        /* If Supported greater than limit in module param, limit it */
-       if (rc_sup > (qib_pcie_caps & 7))
-               rc_sup = qib_pcie_caps & 7;
+       if (rc_mpss > (qib_pcie_caps & 7))
+               rc_mpss = qib_pcie_caps & 7;
        /* If less than (allowed, supported), bump root payload */
-       if (rc_sup > rc_cur) {
-               rc_cur = rc_sup;
-               pctl = (pctl & ~PCI_EXP_DEVCTL_PAYLOAD) |
-                       val2fld(rc_cur, PCI_EXP_DEVCTL_PAYLOAD);
-               pcie_capability_write_word(parent, PCI_EXP_DEVCTL, pctl);
+       if (rc_mpss > rc_mps) {
+               rc_mps = rc_mpss;
+               pcie_set_mps(parent, 128 << rc_mps);
        }
        /* If less than (allowed, supported), bump endpoint payload */
-       if (rc_sup > ep_cur) {
-               ep_cur = rc_sup;
-               ectl = (ectl & ~PCI_EXP_DEVCTL_PAYLOAD) |
-                       val2fld(ep_cur, PCI_EXP_DEVCTL_PAYLOAD);
-               pcie_capability_write_word(dd->pcidev, PCI_EXP_DEVCTL, ectl);
+       if (rc_mpss > ep_mps) {
+               ep_mps = rc_mpss;
+               pcie_set_mps(dd->pcidev, 128 << ep_mps);
        }
 
        /*
@@ -636,23 +602,21 @@ static int qib_tune_pcie_caps(struct qib_devdata *dd)
         * No field for max supported, but PCIe spec limits it to 4096,
         * which is code '5' (log2(4096) - 7)
         */
-       rc_sup = 5;
-       if (rc_sup > ((qib_pcie_caps >> 4) & 7))
-               rc_sup = (qib_pcie_caps >> 4) & 7;
-       rc_cur = fld2val(pctl, PCI_EXP_DEVCTL_READRQ);
-       ep_cur = fld2val(ectl, PCI_EXP_DEVCTL_READRQ);
-
-       if (rc_sup > rc_cur) {
-               rc_cur = rc_sup;
-               pctl = (pctl & ~PCI_EXP_DEVCTL_READRQ) |
-                       val2fld(rc_cur, PCI_EXP_DEVCTL_READRQ);
-               pcie_capability_write_word(parent, PCI_EXP_DEVCTL, pctl);
+       max_mrrs = 5;
+       if (max_mrrs > ((qib_pcie_caps >> 4) & 7))
+               max_mrrs = (qib_pcie_caps >> 4) & 7;
+
+       max_mrrs = 128 << max_mrrs;
+       rc_mrrs = pcie_get_readrq(parent);
+       ep_mrrs = pcie_get_readrq(dd->pcidev);
+
+       if (max_mrrs > rc_mrrs) {
+               rc_mrrs = max_mrrs;
+               pcie_set_readrq(parent, rc_mrrs);
        }
-       if (rc_sup > ep_cur) {
-               ep_cur = rc_sup;
-               ectl = (ectl & ~PCI_EXP_DEVCTL_READRQ) |
-                       val2fld(ep_cur, PCI_EXP_DEVCTL_READRQ);
-               pcie_capability_write_word(dd->pcidev, PCI_EXP_DEVCTL, ectl);
+       if (max_mrrs > ep_mrrs) {
+               ep_mrrs = max_mrrs;
+               pcie_set_readrq(dd->pcidev, ep_mrrs);
        }
 bail:
        return ret;