Commit da0159fd authored Apr 22, 2014 by Joel Fernandes Committed by Tony Lindgren Apr 25, 2014

ARM: OMAP5: Switch to THUMB mode if needed on secondary CPU



On my DRA7 system, when the kernel is built in Thumb-2 mode, the secondary CPU
(Cortex A15) fails to come up causing SMP boot on second CPU to timeout. This
seems to be because the CPU is in ARM mode once the ROM hands over control to
the kernel.  Switch to Thumb-2 mode if required once the kernel is control of
secondary CPU. On OMAP4 on the other hand, it appears to be in Thumb-2 mode on
entry so this is not required and SMP boot works as is.

Also corrected a spurious '+' and updated copyright information.

Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Nishanth Menon <nm@ti.com>
Tested-by: Nishanth Menon <nm@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Joel Fernandes <joelf@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

parent 1ff3859e

arch/arm/mach-omap2/omap-headsmp.S

+6 −2

Original line number	Diff line number	Diff line
		/*
		* Secondary CPU startup routine source file.
		*
		* Copyright (C) 2009 Texas Instruments, Inc.
		* Copyright (C) 2009-2014 Texas Instruments, Inc.
		*
		* Author:
		* Santosh Shilimkar <santosh.shilimkar@ti.com>
		@@ -28,9 +28,13 @@
		* code. This routine also provides a holding flag into which
		* secondary core is held until we're ready for it to initialise.
		* The primary core will update this flag using a hardware
		+ * register AuxCoreBoot0.
		* register AuxCoreBoot0.
		*/
		ENTRY(omap5_secondary_startup)
		.arm
		THUMB( adr r9, BSYM(wait) ) @ CPU may be entered in ARM mode.
		THUMB( bx r9 ) @ If this is a Thumb-2 kernel,
		THUMB( .thumb ) @ switch to Thumb now.
		wait: ldr r2, =AUX_CORE_BOOT0_PA @ read from AuxCoreBoot0
		ldr r0, [r2]
		mov r0, r0, lsr #5