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path: root/drivers/pci/pci.c
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Diffstat (limited to 'drivers/pci/pci.c')
-rw-r--r--drivers/pci/pci.c67
1 files changed, 67 insertions, 0 deletions
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);