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

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@animalcreek.com>
[khilman@ti.com: use soc_is_am35xx() instead of cpu_is_am35xx()]
Signed-off-by: Kevin Hilman <khilman@ti.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/id.c b/arch/arm/mach-omap2/id.c
index f611e3097157..38ae74f8e77a 100644
--- a/arch/arm/mach-omap2/id.c
+++ b/arch/arm/mach-omap2/id.c
@@ -247,6 +247,17 @@ 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 (soc_is_am35xx())
+                omap_features &= ~(OMAP3_HAS_IVA | OMAP3_HAS_ISP);
+
+        /*
          * TODO: Get additional info (where applicable)
          *       e.g. Size of L2 cache.
          */