[PATCH] arm: omap3: am35x: Don't mark missing features as present

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From: "Mark A. Greer" <mgreer@xxxxxxxxxxxxxxx>

The Chip Identification register on the am35x family of SoCs
has bits 12, 7:5, and 3:2 marked as reserved and are read as
zeroes.  Unfortunately, on other omap SoCs, a 0 bit means a
feature is "Full Use" so the OMAP3_CHECK_FEATURE() macro
called by omap3_check_features() will incorrectly interpret
those zeroes to mean that a feature is present even though it
isn't.  To fix that, the feature bits that are incorrectly
set (namely, OMAP3_HAS_IVA and OMAP3_HAS_ISP) need to be
cleared after all of the calls to OMAP3_CHECK_FEATURE() in
omap3_check_features() are made.

Signed-off-by: Mark A. Greer <mgreer@xxxxxxxxxxxxxxx>
---
 arch/arm/mach-omap2/id.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/arm/mach-omap2/id.c b/arch/arm/mach-omap2/id.c
index 0e79b7b..9736049 100644
--- a/arch/arm/mach-omap2/id.c
+++ b/arch/arm/mach-omap2/id.c
@@ -248,6 +248,17 @@ void __init omap3xxx_check_features(void)
 	omap_features |= OMAP3_HAS_SDRC;
 
 	/*
+	 * am35x fixups:
+	 * - The am35x Chip ID register has bits 12, 7:5, and 3:2 marked as
+	 *   reserved and therefore return 0 when read.  Unfortunately,
+	 *   OMAP3_CHECK_FEATURE() will interpret some of those zeroes to
+	 *   mean that a feature is present even though it isn't so clear
+	 *   the incorrectly set feature bits.
+	 */
+	if (cpu_is_omap3505() || cpu_is_omap3517())
+		omap_features &= ~(OMAP3_HAS_IVA | OMAP3_HAS_ISP);
+
+	/*
 	 * TODO: Get additional info (where applicable)
 	 *       e.g. Size of L2 cache.
 	 */
-- 
1.7.9.4

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