[OpenWrt-Devel] [PATCH 2/2] cns3xxx: set both MPS 'and' MRSS to 128

[Pushpal Sidhu]

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 at gateworks.com>
---
 ...ER-to-set-MRSS-128-to-fix-CNS3xxx-BM-DMA..patch | 23 ++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 target/linux/cns3xxx/patches-4.4/130-Extend-PCIE_BUS_PEER2PEER-to-set-MRSS-128-to-fix-CNS3xxx-BM-DMA..patch

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
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;
-- 
2.7.2
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