pdev->pcie_cap = pos;
pci_read_config_word(pdev, pos + PCI_EXP_FLAGS, ®16);
pdev->pcie_type = (reg16 & PCI_EXP_FLAGS_TYPE) >> 4;
+ pci_read_config_word(pdev, pos + PCI_EXP_DEVCAP, ®16);
+ pdev->pcie_mpss = reg16 & PCI_EXP_DEVCAP_PAYLOAD;
}
void set_pcie_hotplug_bridge(struct pci_dev *pdev)
return nr;
}
+static int pcie_find_smpss(struct pci_dev *dev, void *data)
+{
+ u8 *smpss = data;
+
+ if (!pci_is_pcie(dev))
+ return 0;
+
+ /* For PCIE hotplug enabled slots not connected directly to a
+ * PCI-E root port, there can be problems when hotplugging
+ * devices. This is due to the possibility of hotplugging a
+ * device into the fabric with a smaller MPS that the devices
+ * currently running have configured. Modifying the MPS on the
+ * running devices could cause a fatal bus error due to an
+ * incoming frame being larger than the newly configured MPS.
+ * To work around this, the MPS for the entire fabric must be
+ * set to the minimum size. Any devices hotplugged into this
+ * fabric will have the minimum MPS set. If the PCI hotplug
+ * slot is directly connected to the root port and there are not
+ * other devices on the fabric (which seems to be the most
+ * common case), then this is not an issue and MPS discovery
+ * will occur as normal.
+ */
+ if (dev->is_hotplug_bridge && (!list_is_singular(&dev->bus->devices) ||
+ (dev->bus->self &&
+ dev->bus->self->pcie_type != PCI_EXP_TYPE_ROOT_PORT)))
+ *smpss = 0;
+
+ if (*smpss > dev->pcie_mpss)
+ *smpss = dev->pcie_mpss;
+
+ return 0;
+}
+
+static void pcie_write_mps(struct pci_dev *dev, int mps)
+{
+ int rc, dev_mpss;
+
+ dev_mpss = 128 << dev->pcie_mpss;
+
+ 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);
+
+ /* For "MPS Force Max", 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.
+ */
+ 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;
+ }
+
+ rc = pcie_set_mps(dev, mps);
+ if (rc)
+ dev_err(&dev->dev, "Failed attempting to set the MPS\n");
+}
+
+static void pcie_write_mrrs(struct pci_dev *dev, int mps)
+{
+ int rc, mrrs, dev_mpss;
+
+ /* 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.
+ */
+ mrrs = min(mps, dev_mpss);
+
+ /* MRRS is a R/W register. Invalid values can be written, but a
+ * subsequent read will verify if the value is acceptable or not.
+ * If the MRRS value provided is not acceptable (e.g., too large),
+ * 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");
+
+ mrrs /= 2;
+ }
+}
+
+static int pcie_bus_configure_set(struct pci_dev *dev, void *data)
+{
+ int mps = 128 << *(u8 *)data;
+
+ if (!pci_is_pcie(dev))
+ return 0;
+
+ dev_dbg(&dev->dev, "Dev MPS %d MPSS %d MRRS %d\n",
+ pcie_get_mps(dev), 128<<dev->pcie_mpss, pcie_get_readrq(dev));
+
+ pcie_write_mps(dev, mps);
+ pcie_write_mrrs(dev, mps);
+
+ dev_dbg(&dev->dev, "Dev MPS %d MPSS %d MRRS %d\n",
+ pcie_get_mps(dev), 128<<dev->pcie_mpss, pcie_get_readrq(dev));
+
+ return 0;
+}
+
+/* pcie_bus_configure_mps requires that pci_walk_bus work in a top-down,
+ * parents then children fashion. If this changes, then this code will not
+ * work as designed.
+ */
+void pcie_bus_configure_settings(struct pci_bus *bus, u8 mpss)
+{
+ u8 smpss = mpss;
+
+ if (!pci_is_pcie(bus->self))
+ return;
+
+ if (pcie_bus_config == PCIE_BUS_SAFE) {
+ pcie_find_smpss(bus->self, &smpss);
+ pci_walk_bus(bus, pcie_find_smpss, &smpss);
+ }
+
+ pcie_bus_configure_set(bus->self, &smpss);
+ pci_walk_bus(bus, pcie_bus_configure_set, &smpss);
+}
+EXPORT_SYMBOL_GPL(pcie_bus_configure_settings);
+
unsigned int __devinit pci_scan_child_bus(struct pci_bus *bus)
{
unsigned int devfn, pass, max = bus->secondary;
git.openpandora.org / pandora-kernel.git / blobdiff