Add check_member macro to allow clean and easy struct offset checking

This patch adds a new static assertion macro that can be used to check
the offsets in structures that overlay register sets at compile time. It
uses the _Static_assert() declaration from the new ISO C11 standard,
which is supported (even without -std=c11) by GCC after version 4.6.
(There is supposedly also support in clang, although I haven't tried
it... let's deal with compiler issues when/if they turn up.)

I've added it to all structures for our current ARM SoCs for now, and I
think every new register overlay we add going forward should use them
(at least for the last member, but feel free to add more if you think
it's useful).

Change-Id: If32510e7049739ad05618d363a854dc372d64386
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/179412
Reviewed-by: David Hendricks <dhendrix@chromium.org>
Reviewed-by: Stefan Reinauer <reinauer@chromium.org>
(cherry picked from commit cef5fa13c31375a316ca4556c0039b17c8ea7900)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6905
Tested-by: build bot (Jenkins)

1 files changed, 2 insertions, 0 deletions

diff --git a/src/soc/nvidia/tegra124/dma.h b/src/soc/nvidia/tegra124/dma.h
index 557cead6be..e37bf743ad 100644
--- a/src/soc/nvidia/tegra124/dma.h
+++ b/src/soc/nvidia/tegra124/dma.h
@@ -70,6 +70,7 @@ struct apb_dma {
 	u32 chan_wr_reg3;	/* 0x50 */
 	u32 channel_swid1;	/* 0x54 */
 } __attribute__((packed));
+check_member(apb_dma, channel_swid1, 0x54);
 
 /*
  * Naming in the doc included a superfluous _CHANNEL_n_ for
@@ -167,6 +168,7 @@ struct apb_dma_channel_regs {
 	u32 wcount;		/* 0x20 */
 	u32 word_transfer;	/* 0x24 */
 } __attribute__((packed));
+check_member(apb_dma_channel_regs, word_transfer, 0x24);
 
 struct apb_dma_channel {
 	const int num;