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, 1 insertions, 0 deletions

diff --git a/src/soc/nvidia/tegra/i2c.h b/src/soc/nvidia/tegra/i2c.h
index 997ec9c18f..5f299e8ac7 100644
--- a/src/soc/nvidia/tegra/i2c.h
+++ b/src/soc/nvidia/tegra/i2c.h
@@ -149,5 +149,6 @@ struct tegra_i2c_regs {
 	uint32_t bus_clear_status;
 	uint32_t spare;
 };
+check_member(tegra_i2c_regs, bus_clear_status, 0x88);
 
 #endif	/* __SOC_NVIDIA_TEGRA_I2C_H__ */