Patchwork UBUNTU: SAUCE: IMX51: only export NEON flag to userspace on Freescale iMX51 rev3.x or later silicon

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Submitter Bryan Wu
Date Jan. 27, 2010, 5 a.m.
Message ID <1264568422-7809-1-git-send-email-bryan.wu@canonical.com>
Download mbox | patch
Permalink /patch/43769/
State Accepted
Delegated to: Andy Whitcroft
Headers show

Comments

Bryan Wu - Jan. 27, 2010, 5 a.m.
BugLink: http://bugs.launchpad.net/bugs/507416

NEON function is broken on old Freescale iMX51 silicons, such as rev1.x and
rev2.x. Since more and more iMX51 based products will move to rev3.x or later
silicon, we need to enable NEON on these newer silicons and disable NEON on
those old ones.

This patch will detect the silicon revision dynamically and only export NEON
flag to userspace on Freescale iMX51 rev3.x or later silicon. It was tested on
Babbage 3.0 board and Babbage 2.x board.

Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
---
 arch/arm/vfp/vfpmodule.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)
Andy Whitcroft - Jan. 27, 2010, 10:35 a.m.
Applied to Lucid.

-apw

Patch

diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 2d7423a..e0d6b01 100644
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -432,6 +432,10 @@  out:
 
 #include <linux/smp.h>
 
+#if defined(CONFIG_ARCH_MX51) && defined(CONFIG_NEON)
+#include <mach/hardware.h>
+#endif
+
 /*
  * VFP support code initialisation.
  */
@@ -498,7 +502,8 @@  static int __init vfp_init(void)
 		 * load/store instructions, integer and single
 		 * precision floating point operations.
 		 */
-		if ((fmrx(MVFR1) & 0x000fff00) == 0x00011100)
+		if (((fmrx(MVFR1) & 0x000fff00) == 0x00011100)
+			&& cpu_is_mx51_rev(CHIP_REV_3_0) > 0)
 			elf_hwcap |= HWCAP_NEON;
 #endif
 	}