[dpdk-dev] [PATCH] pci/uio: enable prefetchable resources mapping

[Changpeng Liu <changpeng.liu@intel.com>]

For PCI prefetchable resources, Linux will create a
write combined file as well, the library will try
to map resourceX_wc file first, if the file does
not exist, then it will map resourceX as usual.

Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
---
 drivers/bus/pci/linux/pci_uio.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/bus/pci/linux/pci_uio.c b/drivers/bus/pci/linux/pci_uio.c
index d423e4b..2957a5f 100644
--- a/drivers/bus/pci/linux/pci_uio.c
+++ b/drivers/bus/pci/linux/pci_uio.c
@@ -293,7 +293,7 @@
 
 	/* update devname for mmap  */
 	snprintf(devname, sizeof(devname),
-			"%s/" PCI_PRI_FMT "/resource%d",
+			"%s/" PCI_PRI_FMT "/resource%d_wc",
 			rte_pci_get_sysfs_path(),
 			loc->domain, loc->bus, loc->devid,
 			loc->function, res_idx);
@@ -307,13 +307,22 @@
 	}
 
 	/*
-	 * open resource file, to mmap it
+	 * open prefetchable resource file first, try to mmap it
 	 */
 	fd = open(devname, O_RDWR);
 	if (fd < 0) {
-		RTE_LOG(ERR, EAL, "Cannot open %s: %s\n",
-				devname, strerror(errno));
-		goto error;
+		snprintf(devname, sizeof(devname),
+				"%s/" PCI_PRI_FMT "/resource%d",
+				rte_pci_get_sysfs_path(),
+				loc->domain, loc->bus, loc->devid,
+				loc->function, res_idx);
+		/* then try to map resource file */
+		fd = open(devname, O_RDWR);
+		if (fd < 0) {
+			RTE_LOG(ERR, EAL, "Cannot open %s: %s\n",
+					devname, strerror(errno));
+			goto error;
+		}
 	}
 
 	/* try mapping somewhere close to the end of hugepages */
-- 
1.9.3