Support setting payload size

5 files changed, 62 insertions, 7 deletions

diff --git a/driver/Makefile b/driver/Makefile
index 3a242dd..83a8c46 100644
--- a/driver/Makefile
+++ b/driver/Makefile
@@ -1,6 +1,6 @@
 
 obj-m := pciDriver.o
-pciDriver-objs := base.o int.o umem.o kmem.o sysfs.o ioctl.o
+pciDriver-objs := base.o int.o umem.o kmem.o sysfs.o ioctl.o compat.o
 
 KERNELDIR ?= /lib/modules/$(shell uname -r)/build
 INSTALLDIR ?= /lib/modules/$(shell uname -r)/kernel/extra
diff --git a/driver/compat.c b/driver/compat.c
new file mode 100644
index 0000000..a632781
--- /dev/null
+++ b/driver/compat.c
@@ -0,0 +1,26 @@
+#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);
+}
diff --git a/driver/compat.h b/driver/compat.h
index 25e402a..fd3f188 100644
--- a/driver/compat.h
+++ b/driver/compat.h
@@ -195,4 +195,7 @@ static inline void set_pages_reserved_compat(unsigned long cpua, unsigned long s
 #endif
 }
 
+int pcidriver_pcie_get_mps(struct pci_dev *dev);
+int pcidriver_pcie_set_mps(struct pci_dev *dev, int mps);
+
 #endif
diff --git a/driver/ioctl.c b/driver/ioctl.c
index e003476..67cdc52 100644
--- a/driver/ioctl.c
+++ b/driver/ioctl.c
@@ -433,7 +433,6 @@ static int ioctl_version(pcidriver_privdata_t *privdata, unsigned long arg)
 	return 0;
 }
 
-
 /**
  *
  * Gets current device and driver configuration
@@ -448,6 +447,7 @@ static int ioctl_device_state(pcidriver_privdata_t *privdata, unsigned long arg)
 
 	info = (pcilib_device_state_t) {
 	    .iommu = iommu_present(privdata->pdev->dev.bus),
+	    .mps = pcidriver_pcie_get_mps(privdata->pdev),
 	    .dma_mask = privdata->pdev->dma_mask
 	};
 
@@ -468,7 +468,7 @@ static int ioctl_set_dma_mask(pcidriver_privdata_t *privdata, unsigned long arg)
 {
 	int err;
 
-	if ((arg < 24) && (arg > 63))
+	if ((arg < 24) || (arg > 64))
 		return -EINVAL;
 
 	err = pci_set_dma_mask(privdata->pdev, DMA_BIT_MASK(arg));
@@ -477,8 +477,29 @@ static int ioctl_set_dma_mask(pcidriver_privdata_t *privdata, unsigned long arg)
 	    return err;
 	}
 	
-	printk(KERN_ERR "pci_set_dma_mask(%lu) successeded\n", arg);
+	return 0;
+}
+
+/**
+ *
+ * Sets Max Payload Size.
+ *
+ * @param arg Not a pointer, but payload size in bits
+ *
+ */
+static int ioctl_set_mps(pcidriver_privdata_t *privdata, unsigned long arg)
+{
+	int err;
 
+	if ((arg != 128) && (arg != 256) && (arg != 512))
+		return -EINVAL;
+
+	err = pcidriver_pcie_set_mps(privdata->pdev, arg);
+	if (err < 0) {
+	    printk(KERN_ERR "pcie_set_mps(%lu) failed\n", arg);
+	    return err;
+	}
+	
 	return 0;
 }
 
@@ -551,6 +572,9 @@ long pcidriver_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		case PCIDRIVER_IOC_DMA_MASK:
 			return ioctl_set_dma_mask(privdata, arg);
 
+		case PCIDRIVER_IOC_MPS:
+			return ioctl_set_mps(privdata, arg);
+
 		default:
 			return -EINVAL;
 	}
diff --git a/driver/pciDriver.h b/driver/pciDriver.h
index d314952..2fda0ff 100644
--- a/driver/pciDriver.h
+++ b/driver/pciDriver.h
@@ -130,8 +130,9 @@ typedef struct {
 } pcilib_driver_version_t;
 
 typedef struct {
-    unsigned long iommu;
-    unsigned long dma_mask;
+    int iommu;						/**< Specifies if IOMMU is enabled or disabled */
+    int mps;						/**< Maximum payload size */
+    unsigned long dma_mask;				/**< DMA mask */
 } pcilib_device_state_t;
 
 typedef struct {
@@ -235,7 +236,8 @@ typedef struct {
 #define PCIDRIVER_IOC_VERSION		_IOR(  PCIDRIVER_IOC_MAGIC, PCIDRIVER_IOC_BASE + 14, pcilib_driver_version_t * )
 #define PCIDRIVER_IOC_DEVICE_STATE	_IOR(  PCIDRIVER_IOC_MAGIC, PCIDRIVER_IOC_BASE + 15, pcilib_device_state_t * )
 #define PCIDRIVER_IOC_DMA_MASK		_IO(   PCIDRIVER_IOC_MAGIC, PCIDRIVER_IOC_BASE + 16)
+#define PCIDRIVER_IOC_MPS		_IO(   PCIDRIVER_IOC_MAGIC, PCIDRIVER_IOC_BASE + 17)
 
-#define PCIDRIVER_IOC_MAX 16
+#define PCIDRIVER_IOC_MAX 17
 
 #endif