PCI: enable MPS "performance" setting to properly handle bridge MPS

[pandora-kernel.git] / drivers / pci / probe.c

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 6ab6bd3..4829424 100644 (file)
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1363,31 +1363,25 @@ static int pcie_find_smpss(struct pci_dev *dev, void *data)
 
 static void pcie_write_mps(struct pci_dev *dev, int mps)
 {
-       int rc, dev_mpss;
-
-       dev_mpss = 128 << dev->pcie_mpss;
+       int rc;
 
        if (pcie_bus_config == PCIE_BUS_PERFORMANCE) {
-               if (dev->bus->self) {
-                       dev_dbg(&dev->bus->dev, "Bus MPSS %d\n",
-                               128 << dev->bus->self->pcie_mpss);
+               mps = 128 << dev->pcie_mpss;
 
-                       /* For "MPS Force Max", the assumption is made that
+               if (dev->pcie_type != PCI_EXP_TYPE_ROOT_PORT && dev->bus->self)
+                       /* For "Performance", the assumption is made that
                         * downstream communication will never be larger than
                         * the MRRS.  So, the MPS only needs to be configured
                         * for the upstream communication.  This being the case,
                         * walk from the top down and set the MPS of the child
                         * to that of the parent bus.
+                        *
+                        * Configure the device MPS with the smaller of the
+                        * device MPSS or the bridge MPS (which is assumed to be
+                        * properly configured at this point to the largest
+                        * allowable MPS based on its parent bus).
                         */
-                       mps = 128 << dev->bus->self->pcie_mpss;
-                       if (mps > dev_mpss)
-                               dev_warn(&dev->dev, "MPS configured higher than"
-                                        " maximum supported by the device.  If"
-                                        " a bus issue occurs, try running with"
-                                        " pci=pcie_bus_safe.\n");
-               }
-
-               dev->pcie_mpss = ffs(mps) - 8;
+                       mps = min(mps, pcie_get_mps(dev->bus->self));
        }
 
        rc = pcie_set_mps(dev, mps);
@@ -1395,25 +1389,22 @@ static void pcie_write_mps(struct pci_dev *dev, int mps)
                dev_err(&dev->dev, "Failed attempting to set the MPS\n");
 }
 
-static void pcie_write_mrrs(struct pci_dev *dev, int mps)
+static void pcie_write_mrrs(struct pci_dev *dev)
 {
-       int rc, mrrs, dev_mpss;
+       int rc, mrrs;
 
        /* In the "safe" case, do not configure the MRRS.  There appear to be
         * issues with setting MRRS to 0 on a number of devices.
         */
-
        if (pcie_bus_config != PCIE_BUS_PERFORMANCE)
                return;
 
-       dev_mpss = 128 << dev->pcie_mpss;
-
        /* For Max performance, the MRRS must be set to the largest supported
         * value.  However, it cannot be configured larger than the MPS the
-        * device or the bus can support.  This assumes that the largest MRRS
-        * available on the device cannot be smaller than the device MPSS.
+        * device or the bus can support.  This should already be properly
+        * configured by a prior call to pcie_write_mps.
         */
-       mrrs = min(mps, dev_mpss);
+       mrrs = pcie_get_mps(dev);
 
        /* MRRS is a R/W register.  Invalid values can be written, but a
         * subsequent read will verify if the value is acceptable or not.
@@ -1421,16 +1412,18 @@ static void pcie_write_mrrs(struct pci_dev *dev, int mps)
         * shrink the value until it is acceptable to the HW.
         */
        while (mrrs != pcie_get_readrq(dev) && mrrs >= 128) {
-               dev_warn(&dev->dev, "Attempting to modify the PCI-E MRRS value"
-                        " to %d.  If any issues are encountered, please try "
-                        "running with pci=pcie_bus_safe\n", mrrs);
                rc = pcie_set_readrq(dev, mrrs);
-               if (rc)
-                       dev_err(&dev->dev,
-                               "Failed attempting to set the MRRS\n");
+               if (!rc)
+                       break;
 
+               dev_warn(&dev->dev, "Failed attempting to set the MRRS\n");
                mrrs /= 2;
        }
+
+       if (mrrs < 128)
+               dev_err(&dev->dev, "MRRS was unable to be configured with a "
+                       "safe value.  If problems are experienced, try running "
+                       "with pci=pcie_bus_safe.\n");
 }
 
 static int pcie_bus_configure_set(struct pci_dev *dev, void *data)
@@ -1444,7 +1437,7 @@ static int pcie_bus_configure_set(struct pci_dev *dev, void *data)
                 pcie_get_mps(dev), 128<<dev->pcie_mpss, pcie_get_readrq(dev));
 
        pcie_write_mps(dev, mps);
-       pcie_write_mrrs(dev, mps);
+       pcie_write_mrrs(dev);
 
        dev_dbg(&dev->dev, "Dev MPS %d MPSS %d MRRS %d\n",
                 pcie_get_mps(dev), 128<<dev->pcie_mpss, pcie_get_readrq(dev));