[dpdk-dev] [PATCH 19/22] igb_uio: add sys files to read/write specific bits in pci config space

[Helin Zhang]

Enabling 'Extended Tag' and resetting 'Max Read Request Size' in PCI config space
have big impacts to i40e performance. They cannot be changed on some BIOS
implementations, though can on others. Two sys files of 'extended_tag' and
'max_read_request_size' are added to support changing them by 'echo' in user space.

Signed-off-by: Helin Zhang <helin.zhang at intel.com>
Signed-off-by: Mark Chen <jing.d.chen at intel.com>
---
 lib/librte_eal/linuxapp/igb_uio/igb_uio.c | 105 ++++++++++++++++++++++++++++++
 1 file changed, 105 insertions(+)

diff --git a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
index 79fe97d..55e801d 100644
--- a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
+++ b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
@@ -47,6 +47,15 @@
 #define PCI_MSIX_ENTRY_CTRL_MASKBIT     1
 #endif
 
+#ifdef RTE_PCI_CONFIG
+#define PCI_SYS_FILE_BUF_SIZE      10
+#define PCI_DEV_CAP_REG            0xA4
+#define PCI_DEV_CTRL_REG           0xA8
+#define PCI_DEV_CAP_EXT_TAG_MASK   0x20
+#define PCI_DEV_CTRL_EXT_TAG_SHIFT 8
+#define PCI_DEV_CTRL_EXT_TAG_MASK  (1 << PCI_DEV_CTRL_EXT_TAG_SHIFT)
+#endif
+
 #define IGBUIO_NUM_MSI_VECTORS 1
 
 /* interrupt mode */
@@ -151,9 +160,105 @@ store_max_vfs(struct device *dev, struct device_attribute *attr,
 	return err ? err : count;							
 }
 
+#ifdef RTE_PCI_CONFIG
+static ssize_t
+show_extended_tag(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct pci_dev *pci_dev = container_of(dev, struct pci_dev, dev);
+	uint32_t val = 0;
+
+	pci_read_config_dword(pci_dev, PCI_DEV_CAP_REG, &val);
+	if (!(val & PCI_DEV_CAP_EXT_TAG_MASK)) /* Not supported */
+		return snprintf(buf, PCI_SYS_FILE_BUF_SIZE, "%s\n", "invalid");
+
+	val = 0;
+	pci_bus_read_config_dword(pci_dev->bus, pci_dev->devfn,
+					PCI_DEV_CTRL_REG, &val);
+
+	return snprintf(buf, PCI_SYS_FILE_BUF_SIZE, "%s\n",
+		(val & PCI_DEV_CTRL_EXT_TAG_MASK) ? "on" : "off");
+}
+
+static ssize_t
+store_extended_tag(struct device *dev,
+		   struct device_attribute *attr,
+		   const char *buf,
+		   size_t count)
+{
+	struct pci_dev *pci_dev = container_of(dev, struct pci_dev, dev);
+	uint32_t val = 0, enable;
+
+	if (strncmp(buf, "on", 2) == 0)
+		enable = 1;
+	else if (strncmp(buf, "off", 3) == 0)
+		enable = 0;
+	else
+		return -EINVAL;
+
+	pci_bus_read_config_dword(pci_dev->bus, pci_dev->devfn,
+					PCI_DEV_CAP_REG, &val);
+	if (!(val & PCI_DEV_CAP_EXT_TAG_MASK)) /* Not supported */
+		return -EPERM;
+
+	val = 0;
+	pci_bus_read_config_dword(pci_dev->bus, pci_dev->devfn,
+					PCI_DEV_CTRL_REG, &val);
+	if (enable)
+		val |= PCI_DEV_CTRL_EXT_TAG_MASK;
+	else
+		val &= ~PCI_DEV_CTRL_EXT_TAG_MASK;
+	pci_bus_write_config_dword(pci_dev->bus, pci_dev->devfn,
+					PCI_DEV_CTRL_REG, val);
+
+	return count;
+}
+
+static ssize_t
+show_max_read_request_size(struct device *dev,
+			   struct device_attribute *attr,
+			   char *buf)
+{
+	struct pci_dev *pci_dev = container_of(dev, struct pci_dev, dev);
+	int val = pcie_get_readrq(pci_dev);
+
+	return snprintf(buf, PCI_SYS_FILE_BUF_SIZE, "%d\n", val);
+}
+
+static ssize_t
+store_max_read_request_size(struct device *dev,
+			    struct device_attribute *attr,
+			    const char *buf,
+			    size_t count)
+{
+	struct pci_dev *pci_dev = container_of(dev, struct pci_dev, dev);
+	unsigned long size = 0;
+	int ret;
+
+	if (strict_strtoul(buf, 0, &size) != 0)
+		return -EINVAL;
+
+	ret = pcie_set_readrq(pci_dev, (int)size);
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+#endif
+
 static DEVICE_ATTR(max_vfs, S_IRUGO | S_IWUSR, show_max_vfs, store_max_vfs);
+#ifdef RTE_PCI_CONFIG
+static DEVICE_ATTR(extended_tag, S_IRUGO | S_IWUSR, show_extended_tag, \
+						store_extended_tag);
+static DEVICE_ATTR(max_read_request_size, S_IRUGO | S_IWUSR, \
+	show_max_read_request_size, store_max_read_request_size);
+#endif
+
 static struct attribute *dev_attrs[] = {
 	&dev_attr_max_vfs.attr,
+#ifdef RTE_PCI_CONFIG
+	&dev_attr_extended_tag.attr,
+	&dev_attr_max_read_request_size.attr,
+#endif
         NULL,
 };
 
-- 
1.8.1.4