lkml.org 
[lkml]   [2019]   [Jan]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 2/5] swiotlb: Add is_swiotlb_active() function
Date
From: Joerg Roedel <jroedel@suse.de>

This function will be used from dma_direct code to determine
the maximum segment size of a dma mapping.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
include/linux/swiotlb.h | 6 ++++++
kernel/dma/swiotlb.c | 9 +++++++++
2 files changed, 15 insertions(+)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 1c22d96e1742..e9e786b4b598 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -63,6 +63,7 @@ extern void swiotlb_tbl_sync_single(struct device *hwdev,
extern int
swiotlb_dma_supported(struct device *hwdev, u64 mask);
size_t swiotlb_max_mapping_size(struct device *dev);
+bool is_swiotlb_active(void);

#ifdef CONFIG_SWIOTLB
extern enum swiotlb_force swiotlb_force;
@@ -100,6 +101,11 @@ static inline size_t swiotlb_max_mapping_size(struct device *dev)
{
return SIZE_MAX;
}
+
+static inline bool is_swiotlb_active(void)
+{
+ return false;
+}
#endif /* CONFIG_SWIOTLB */

extern void swiotlb_print_info(void);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 9cb21259cb0b..c873f9cc2146 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -667,3 +667,12 @@ size_t swiotlb_max_mapping_size(struct device *dev)
{
return ((size_t)1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;
}
+
+bool is_swiotlb_active(void)
+{
+ /*
+ * When SWIOTLB is initialized, even if io_tlb_start points to physical
+ * address zero, io_tlb_end surely doesn't.
+ */
+ return io_tlb_end != 0;
+}
--
2.17.1
\
 
 \ /
  Last update: 2019-01-30 17:42    [W:0.091 / U:18.036 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site