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-rw-r--r--arch/x86/pci/acpi.c9
-rw-r--r--drivers/pci/hotplug/pcihp_slot.c45
-rw-r--r--drivers/pci/pci.c67
-rw-r--r--drivers/pci/probe.c145
-rw-r--r--include/linux/pci.h15
5 files changed, 236 insertions, 45 deletions
diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index ae3cb23cd89..c95330267f0 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -360,6 +360,15 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)
}
}
+ /* After the PCI-E bus has been walked and all devices discovered,
+ * configure any settings of the fabric that might be necessary.
+ */
+ if (bus) {
+ struct pci_bus *child;
+ list_for_each_entry(child, &bus->children, node)
+ pcie_bus_configure_settings(child, child->self->pcie_mpss);
+ }
+
if (!bus)
kfree(sd);
diff --git a/drivers/pci/hotplug/pcihp_slot.c b/drivers/pci/hotplug/pcihp_slot.c
index 749fdf07031..753b21aaea6 100644
--- a/drivers/pci/hotplug/pcihp_slot.c
+++ b/drivers/pci/hotplug/pcihp_slot.c
@@ -158,47 +158,6 @@ static void program_hpp_type2(struct pci_dev *dev, struct hpp_type2 *hpp)
*/
}
-/* Program PCIE MaxPayload setting on device: ensure parent maxpayload <= device */
-static int pci_set_payload(struct pci_dev *dev)
-{
- int pos, ppos;
- u16 pctl, psz;
- u16 dctl, dsz, dcap, dmax;
- struct pci_dev *parent;
-
- parent = dev->bus->self;
- pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
- if (!pos)
- return 0;
-
- /* Read Device MaxPayload capability and setting */
- pci_read_config_word(dev, pos + PCI_EXP_DEVCTL, &dctl);
- pci_read_config_word(dev, pos + PCI_EXP_DEVCAP, &dcap);
- dsz = (dctl & PCI_EXP_DEVCTL_PAYLOAD) >> 5;
- dmax = (dcap & PCI_EXP_DEVCAP_PAYLOAD);
-
- /* Read Parent MaxPayload setting */
- ppos = pci_find_capability(parent, PCI_CAP_ID_EXP);
- if (!ppos)
- return 0;
- pci_read_config_word(parent, ppos + PCI_EXP_DEVCTL, &pctl);
- psz = (pctl & PCI_EXP_DEVCTL_PAYLOAD) >> 5;
-
- /* If parent payload > device max payload -> error
- * If parent payload > device payload -> set speed
- * If parent payload <= device payload -> do nothing
- */
- if (psz > dmax)
- return -1;
- else if (psz > dsz) {
- dev_info(&dev->dev, "Setting MaxPayload to %d\n", 128 << psz);
- pci_write_config_word(dev, pos + PCI_EXP_DEVCTL,
- (dctl & ~PCI_EXP_DEVCTL_PAYLOAD) +
- (psz << 5));
- }
- return 0;
-}
-
void pci_configure_slot(struct pci_dev *dev)
{
struct pci_dev *cdev;
@@ -210,9 +169,7 @@ void pci_configure_slot(struct pci_dev *dev)
(dev->class >> 8) == PCI_CLASS_BRIDGE_PCI)))
return;
- ret = pci_set_payload(dev);
- if (ret)
- dev_warn(&dev->dev, "could not set device max payload\n");
+ pcie_bus_configure_settings(dev->bus, dev->bus->self->pcie_mpss);
memset(&hpp, 0, sizeof(hpp));
ret = pci_get_hp_params(dev, &hpp);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 08a95b369d8..466fad6e6ee 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -77,6 +77,8 @@ unsigned long pci_cardbus_mem_size = DEFAULT_CARDBUS_MEM_SIZE;
unsigned long pci_hotplug_io_size = DEFAULT_HOTPLUG_IO_SIZE;
unsigned long pci_hotplug_mem_size = DEFAULT_HOTPLUG_MEM_SIZE;
+enum pcie_bus_config_types pcie_bus_config = PCIE_BUS_PERFORMANCE;
+
/*
* The default CLS is used if arch didn't set CLS explicitly and not
* all pci devices agree on the same value. Arch can override either
@@ -3223,6 +3225,67 @@ out:
EXPORT_SYMBOL(pcie_set_readrq);
/**
+ * pcie_get_mps - get PCI Express maximum payload size
+ * @dev: PCI device to query
+ *
+ * Returns maximum payload size in bytes
+ * or appropriate error value.
+ */
+int pcie_get_mps(struct pci_dev *dev)
+{
+ int ret, cap;
+ u16 ctl;
+
+ cap = pci_pcie_cap(dev);
+ if (!cap)
+ return -EINVAL;
+
+ ret = pci_read_config_word(dev, cap + PCI_EXP_DEVCTL, &ctl);
+ if (!ret)
+ ret = 128 << ((ctl & PCI_EXP_DEVCTL_PAYLOAD) >> 5);
+
+ return ret;
+}
+
+/**
+ * pcie_set_mps - set PCI Express maximum payload size
+ * @dev: PCI device to query
+ * @rq: maximum payload size in bytes
+ * valid values are 128, 256, 512, 1024, 2048, 4096
+ *
+ * If possible sets maximum payload size
+ */
+int pcie_set_mps(struct pci_dev *dev, int mps)
+{
+ int cap, err = -EINVAL;
+ u16 ctl, v;
+
+ if (mps < 128 || mps > 4096 || !is_power_of_2(mps))
+ goto out;
+
+ v = ffs(mps) - 8;
+ if (v > dev->pcie_mpss)
+ goto out;
+ v <<= 5;
+
+ cap = pci_pcie_cap(dev);
+ if (!cap)
+ goto out;
+
+ err = pci_read_config_word(dev, cap + PCI_EXP_DEVCTL, &ctl);
+ if (err)
+ goto out;
+
+ if ((ctl & PCI_EXP_DEVCTL_PAYLOAD) != v) {
+ ctl &= ~PCI_EXP_DEVCTL_PAYLOAD;
+ ctl |= v;
+ err = pci_write_config_word(dev, cap + PCI_EXP_DEVCTL, ctl);
+ }
+out:
+ return err;
+}
+
+/**
* pci_select_bars - Make BAR mask from the type of resource
* @dev: the PCI device for which BAR mask is made
* @flags: resource type mask to be selected
@@ -3505,6 +3568,10 @@ static int __init pci_setup(char *str)
pci_hotplug_io_size = memparse(str + 9, &str);
} else if (!strncmp(str, "hpmemsize=", 10)) {
pci_hotplug_mem_size = memparse(str + 10, &str);
+ } else if (!strncmp(str, "pcie_bus_safe", 13)) {
+ pcie_bus_config = PCIE_BUS_SAFE;
+ } else if (!strncmp(str, "pcie_bus_perf", 13)) {
+ pcie_bus_config = PCIE_BUS_PERFORMANCE;
} else {
printk(KERN_ERR "PCI: Unknown option `%s'\n",
str);
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 795c9026d55..5becf7cd50d 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -856,6 +856,8 @@ void set_pcie_port_type(struct pci_dev *pdev)
pdev->pcie_cap = pos;
pci_read_config_word(pdev, pos + PCI_EXP_FLAGS, &reg16);
pdev->pcie_type = (reg16 & PCI_EXP_FLAGS_TYPE) >> 4;
+ pci_read_config_word(pdev, pos + PCI_EXP_DEVCAP, &reg16);
+ pdev->pcie_mpss = reg16 & PCI_EXP_DEVCAP_PAYLOAD;
}
void set_pcie_hotplug_bridge(struct pci_dev *pdev)
@@ -1326,6 +1328,149 @@ int pci_scan_slot(struct pci_bus *bus, int devfn)
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->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;
+
+ 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;
+
+
+ /* MRRS is a R/W register. Invalid values can be written, but a
+ * subsiquent 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");
+
+ 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_info(&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_info(&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 (!bus->self)
+ return;
+
+ 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);
+}
+
unsigned int __devinit pci_scan_child_bus(struct pci_bus *bus)
{
unsigned int devfn, pass, max = bus->secondary;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index f27893b3b72..1ff9bbafd93 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -251,7 +251,8 @@ struct pci_dev {
u8 revision; /* PCI revision, low byte of class word */
u8 hdr_type; /* PCI header type (`multi' flag masked out) */
u8 pcie_cap; /* PCI-E capability offset */
- u8 pcie_type; /* PCI-E device/port type */
+ u8 pcie_type:4; /* PCI-E device/port type */
+ u8 pcie_mpss:3; /* PCI-E Max Payload Size Supported */
u8 rom_base_reg; /* which config register controls the ROM */
u8 pin; /* which interrupt pin this device uses */
@@ -617,6 +618,16 @@ struct pci_driver {
/* these external functions are only available when PCI support is enabled */
#ifdef CONFIG_PCI
+extern void pcie_bus_configure_settings(struct pci_bus *bus, u8 smpss);
+
+enum pcie_bus_config_types {
+ PCIE_BUS_PERFORMANCE,
+ PCIE_BUS_SAFE,
+ PCIE_BUS_PEER2PEER,
+};
+
+extern enum pcie_bus_config_types pcie_bus_config;
+
extern struct bus_type pci_bus_type;
/* Do NOT directly access these two variables, unless you are arch specific pci
@@ -796,6 +807,8 @@ int pcix_get_mmrbc(struct pci_dev *dev);
int pcix_set_mmrbc(struct pci_dev *dev, int mmrbc);
int pcie_get_readrq(struct pci_dev *dev);
int pcie_set_readrq(struct pci_dev *dev, int rq);
+int pcie_get_mps(struct pci_dev *dev);
+int pcie_set_mps(struct pci_dev *dev, int mps);
int __pci_reset_function(struct pci_dev *dev);
int pci_reset_function(struct pci_dev *dev);
void pci_update_resource(struct pci_dev *dev, int resno);