[PATCH] modify the IO_TLB_SEGSIZE to configtable as flexible requirement about IOMMU/SW-IOMMU.

[xiaomin1 <xiaoming.wang@intel.com>]

The maximum of SW-IOMMU is limited to 2^11*128 = 256K.
While in different platform and different requirements this seems improper.
So modify the IO_TLB_SEGSIZE to configtable is make sense.
Example:
If 1M bytes are requied. There has an error like.
[ 33.293120] DMA: Out of SW-IOMMU space for 1048576 bytes at device gadget

Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Zhang Dongxing <dongxing.zhang@intel.com>
Signed-off-by: xiaomin1 <xiaoming.wang@intel.com>
---
 include/linux/swiotlb.h |    2 +-
 lib/Kconfig             |    4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index e7a018e..5ab10b9 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -14,7 +14,7 @@ extern int swiotlb_force;
  * must be a power of 2.  What is the appropriate value ?
  * The complexity of {map,unmap}_single is linearly dependent on this value.
  */
-#define IO_TLB_SEGSIZE	128
+#define IO_TLB_SEGSIZE	CONFIG_DEFAULT_IO_TLB_SEGSIZE
 
 /*
  * log of the size of each IO TLB slab.  The number of slabs is command line
diff --git a/lib/Kconfig b/lib/Kconfig
index 54cf309..76f1108 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -518,4 +518,8 @@ source "lib/fonts/Kconfig"
 config ARCH_HAS_SG_CHAIN
 	def_bool n
 
+config DEFAULT_IO_TLB_SEGSIZE
+	int
+	default 128
+
 endmenu
-- 
1.7.9.5