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authorKieran Bingham <kieran.bingham+renesas@ideasonboard.com>2018-08-03 07:37:21 -0400
committerMauro Carvalho Chehab <mchehab+samsung@kernel.org>2018-08-03 15:55:49 -0400
commit3e737e394329564b70ceff8eb0c5f587904aa396 (patch)
treeee5e23f0acb51d1efccd665d0f24c747dac3ef5f /drivers/media
parent3c56b2cccbd1d66ab394ca73f4de48d8c98d923d (diff)
downloadlinux-3e737e394329564b70ceff8eb0c5f587904aa396.tar.bz2
media: vsp1: use kernel __packed for structures
The kernel provides a __packed definition to abstract away from the compiler specific attributes tag. Convert all packed structures in VSP1 to use it. The GCC documentation [0] describes this attribute as "the structure or union is placed to minimize the memory required". The Keil compiler documentation at [1] warns that the use of this attribute can cause a performance penalty in the event that the compiler can not deduce the allignment of each field. Careful examination of the object code generated both with and without this attribute shows that these structures are accessed identically and are not affected by any performance penalty. The structures are correctly aligned and padded to match the needs of the hardware already. This patch does not serve to make a decision as to the use of the attribute, but purely to clean up the code to use the kernel defined abstraction as per [2]. [0] https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-packed-type-attribute [1] http://www.keil.com/support/man/docs/armcc/armcc_chr1359124230195.htm [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/compiler-gcc.h?h=v4.16-rc5#n92 Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Diffstat (limited to 'drivers/media')
-rw-r--r--drivers/media/platform/vsp1/vsp1_dl.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/media/platform/vsp1/vsp1_dl.c b/drivers/media/platform/vsp1/vsp1_dl.c
index 10a24bde2299..e4aae334f047 100644
--- a/drivers/media/platform/vsp1/vsp1_dl.c
+++ b/drivers/media/platform/vsp1/vsp1_dl.c
@@ -25,19 +25,19 @@
struct vsp1_dl_header_list {
u32 num_bytes;
u32 addr;
-} __attribute__((__packed__));
+} __packed;
struct vsp1_dl_header {
u32 num_lists;
struct vsp1_dl_header_list lists[8];
u32 next_header;
u32 flags;
-} __attribute__((__packed__));
+} __packed;
struct vsp1_dl_entry {
u32 addr;
u32 data;
-} __attribute__((__packed__));
+} __packed;
/**
* struct vsp1_dl_body - Display list body