1 files changed, 25 insertions, 0 deletions
diff --git a/driver/pcibus.c b/driver/pcibus.c
new file mode 100644
index 0000000..f28f527
--- /dev/null
+++ b/driver/pcibus.c
@@ -0,0 +1,25 @@
+#include <linux/pci.h>
+
+int pcidriver_pcie_get_mps(struct pci_dev *dev)
+{
+    u16 ctl;
+
+    pcie_capability_read_word(dev, PCI_EXP_DEVCTL, &ctl);
+
+    return 128 << ((ctl & PCI_EXP_DEVCTL_PAYLOAD) >> 5);
+}
+
+int pcidriver_pcie_set_mps(struct pci_dev *dev, int mps)
+{
+    u16 v;
+
+    if (mps < 128 || mps > 4096 || !is_power_of_2(mps))
+        return -EINVAL;
+
+    v = ffs(mps) - 8;
+    if (v > dev->pcie_mpss)
+        return -EINVAL;
+    v <<= 5;
+
+    return pcie_capability_clear_and_set_word(dev, PCI_EXP_DEVCTL, PCI_EXP_DEVCTL_PAYLOAD, v);
+}