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, 3 insertions, 1 deletions

diff --git a/src/soc/samsung/exynos5250/dmc.h b/src/soc/samsung/exynos5250/dmc.h
index 6388316c5e..acd9850a04 100644
--- a/src/soc/samsung/exynos5250/dmc.h
+++ b/src/soc/samsung/exynos5250/dmc.h
@@ -115,6 +115,7 @@ struct exynos5_dmc {
 	unsigned char res34[0xc];
 	unsigned int pmcnt3_ppc_a;
 };
+check_member(exynos5_dmc, pmcnt3_ppc_a, 0xe140);
 
 static struct exynos5_dmc * const exynos_dmc = (void *)EXYNOS5_DMC_CTRL_BASE;
 
@@ -136,7 +137,7 @@ struct exynos5_phy_control {
 	unsigned int phy_con14;
 	unsigned int phy_con15;
 	unsigned int phy_con16;
-	unsigned char res4[4];
+	unsigned char res4[4];	/* NOT a mistake. Yes, it doesn't make sense. */
 	unsigned int phy_con17;
 	unsigned int phy_con18;
 	unsigned int phy_con19;
@@ -164,6 +165,7 @@ struct exynos5_phy_control {
 	unsigned int phy_con41;
 	unsigned int phy_con42;
 };
+check_member(exynos5_phy_control, phy_con42, 0xac);
 
 static struct exynos5_phy_control * const exynos_phy0_control =
 		(void *)EXYNOS5_DMC_PHY0_BASE;