cns3xxx: set both MPS 'and' MRSS to 128

Fixes some DMA issues with this platform. Because this isn't currently accepted,
and can potentially disrupt other platforms (as read in commit log), I will
leave this cns3xxx specific.

Original Patch: https://patchwork.ozlabs.org/patch/600024/

Signed-off-by: Pushpal Sidhu <psidhu@gateworks.com>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@49249 3c298f89-4303-0410-b956-a3cf2f4a3e73

diff --git a/target/linux/cns3xxx/patches-4.4/130-Extend-PCIE_BUS_PEER2PEER-to-set-MRSS-128-to-fix-CNS3xxx-BM-DMA..patch b/target/linux/cns3xxx/patches-4.4/130-Extend-PCIE_BUS_PEER2PEER-to-set-MRSS-128-to-fix-CNS3xxx-BM-DMA..patch
new file mode 100644 (file)
index 0000000..208c80a
--- /dev/null
+++ b/target/linux/cns3xxx/patches-4.4/130-Extend-PCIE_BUS_PEER2PEER-to-set-MRSS-128-to-fix-CNS3xxx-BM-DMA..patch
@@ -0,0 +1,23 @@
+--- a/drivers/pci/probe.c
++++ b/drivers/pci/probe.c
+@@ -1924,7 +1924,8 @@ static void pcie_write_mrrs(struct pci_d
+       /* In the "safe" case, do not configure the MRRS.  There appear to be
+        * issues with setting MRRS to 0 on a number of devices.
+        */
+-      if (pcie_bus_config != PCIE_BUS_PERFORMANCE)
++      if (pcie_bus_config != PCIE_BUS_PERFORMANCE &&
++          pcie_bus_config != PCIE_BUS_PEER2PEER)
+               return;
+ 
+       /* For Max performance, the MRRS must be set to the largest supported
+--- a/include/linux/pci.h
++++ b/include/linux/pci.h
+@@ -756,7 +756,7 @@ enum pcie_bus_config_types {
+       PCIE_BUS_DEFAULT,       /* ensure MPS matches upstream bridge */
+       PCIE_BUS_SAFE,          /* use largest MPS boot-time devices support */
+       PCIE_BUS_PERFORMANCE,   /* use MPS and MRRS for best performance */
+-      PCIE_BUS_PEER2PEER,     /* set MPS = 128 for all devices */
++      PCIE_BUS_PEER2PEER,     /* set MPS and MRSS to 128 for all devices */
+ };
+ 
+ extern enum pcie_bus_config_types pcie_bus_config;