* will occur as normal.
*/
if (dev->is_hotplug_bridge && (!list_is_singular(&dev->bus->devices) ||
- dev->bus->self->pcie_type != PCI_EXP_TYPE_ROOT_PORT))
+ (dev->bus->self &&
+ dev->bus->self->pcie_type != PCI_EXP_TYPE_ROOT_PORT)))
*smpss = 0;
if (*smpss > dev->pcie_mpss)
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);
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;
- if (pcie_bus_config == PCIE_BUS_PERFORMANCE) {
- int 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 = mps < dev_mpss ? mps : dev_mpss;
- } else
- /* In the "safe" case, configure the MRRS for fairness on the
- * bus by making all devices have the same size
- */
- mrrs = mps;
+ /* 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;
+ /* 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 should already be properly
+ * configured by a prior call to pcie_write_mps.
+ */
+ mrrs = pcie_get_mps(dev);
/* MRRS is a R/W register. Invalid values can be written, but a
- * subsiquent read will verify if the value is acceptable or not.
+ * 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) {
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)
{
- int mps = 128 << *(u8 *)data;
+ int mps, orig_mps;
if (!pci_is_pcie(dev))
return 0;
- dev_info(&dev->dev, "Dev MPS %d MPSS %d MRRS %d\n",
- pcie_get_mps(dev), 128<<dev->pcie_mpss, pcie_get_readrq(dev));
+ mps = 128 << *(u8 *)data;
+ orig_mps = pcie_get_mps(dev);
pcie_write_mps(dev, mps);
- pcie_write_mrrs(dev, mps);
+ pcie_write_mrrs(dev);
- dev_info(&dev->dev, "Dev MPS %d MPSS %d MRRS %d\n",
- pcie_get_mps(dev), 128<<dev->pcie_mpss, pcie_get_readrq(dev));
+ dev_info(&dev->dev, "PCI-E Max Payload Size set to %4d/%4d (was %4d), "
+ "Max Read Rq %4d\n", pcie_get_mps(dev), 128 << dev->pcie_mpss,
+ orig_mps, pcie_get_readrq(dev));
return 0;
}
-/* pcie_bus_configure_mps requires that pci_walk_bus work in a top-down,
+/* pcie_bus_configure_settings 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;
+ u8 smpss;
- if (!bus->self)
+ if (!pci_is_pcie(bus->self))
return;
- if (!pci_is_pcie(bus->self))
+ if (pcie_bus_config == PCIE_BUS_TUNE_OFF)
return;
+ /* FIXME - Peer to peer DMA is possible, though the endpoint would need
+ * to be aware to the MPS of the destination. To work around this,
+ * simply force the MPS of the entire system to the smallest possible.
+ */
+ if (pcie_bus_config == PCIE_BUS_PEER2PEER)
+ smpss = 0;
+
if (pcie_bus_config == PCIE_BUS_SAFE) {
+ smpss = mpss;
+
pcie_find_smpss(bus->self, &smpss);
pci_walk_bus(bus, pcie_find_smpss, &smpss);
}
projects / cascardo / linux.git / blobdiff