linux/arch/arm/mach-imx/headsmp.S

/*
 * Copyright 2011 Freescale Semiconductor, Inc.
 * Copyright 2011 Linaro Ltd.
 *
 * The code contained herein is licensed under the GNU General Public
 * License. You may obtain a copy of the GNU General Public License
 * Version 2 or later at the following locations:
 *
 * http://www.opensource.org/licenses/gpl-license.html
 * http://www.gnu.org/copyleft/gpl.html
 */

#include <linux/linkage.h>
#include <linux/init.h>
#include <asm/asm-offsets.h>
#include <asm/hardware/cache-l2x0.h>

	.section ".text.head", "ax"

/*
 * The secondary kernel init calls v7_flush_dcache_all before it enables
 * the L1; however, the L1 comes out of reset in an undefined state, so
 * the clean + invalidate performed by v7_flush_dcache_all causes a bunch
 * of cache lines with uninitialized data and uninitialized tags to get
 * written out to memory, which does really unpleasant things to the main
 * processor.  We fix this by performing an invalidate, rather than a
 * clean + invalidate, before jumping into the kernel.
 *
 * This funciton is cloned from arch/arm/mach-tegra/headsmp.S, and needs
 * to be called for both secondary cores startup and primary core resume
 * procedures.  Ideally, it should be moved into arch/arm/mm/cache-v7.S.
 */
ENTRY(v7_invalidate_l1)
	mov	r0, #0
	mcr	p15, 0, r0, c7, c5, 0	@ invalidate I cache
	mcr	p15, 2, r0, c0, c0, 0
	mrc	p15, 1, r0, c0, c0, 0

	ldr	r1, =0x7fff
	and	r2, r1, r0, lsr #13

	ldr	r1, =0x3ff

	and	r3, r1, r0, lsr #3	@ NumWays - 1
	add	r2, r2, #1		@ NumSets

	and	r0, r0, #0x7
	add	r0, r0, #4	@ SetShift

	clz	r1, r3		@ WayShift
	add	r4, r3, #1	@ NumWays
1:	sub	r2, r2, #1	@ NumSets--
	mov	r3, r4		@ Temp = NumWays
2:	subs	r3, r3, #1	@ Temp--
	mov	r5, r3, lsl r1
	mov	r6, r2, lsl r0
	orr	r5, r5, r6	@ Reg = (Temp<<WayShift)|(NumSets<<SetShift)
	mcr	p15, 0, r5, c7, c6, 2
	bgt	2b
	cmp	r2, #0
	bgt	1b
	dsb
	isb
	mov	pc, lr
ENDPROC(v7_invalidate_l1)

#ifdef CONFIG_SMP
ENTRY(v7_secondary_startup)
	bl	v7_invalidate_l1
	b	secondary_startup
ENDPROC(v7_secondary_startup)
#endif

#ifdef CONFIG_PM
/*
 * The following code is located into the .data section.  This is to
 * allow phys_l2x0_saved_regs to be accessed with a relative load
 * as we are running on physical address here.
 */
	.data
	.align

#ifdef CONFIG_CACHE_L2X0
	.macro	pl310_resume
	ldr	r2, phys_l2x0_saved_regs
	ldr	r0, [r2, #L2X0_R_PHY_BASE]	@ get physical base of l2x0
	ldr	r1, [r2, #L2X0_R_AUX_CTRL]	@ get aux_ctrl value
	str	r1, [r0, #L2X0_AUX_CTRL]	@ restore aux_ctrl
	mov	r1, #0x1
	str	r1, [r0, #L2X0_CTRL]		@ re-enable L2
	.endm

	.globl	phys_l2x0_saved_regs
phys_l2x0_saved_regs:
        .long   0
#else
	.macro	pl310_resume
	.endm
#endif

ENTRY(v7_cpu_resume)
	bl	v7_invalidate_l1
	pl310_resume
	b	cpu_resume
ENDPROC(v7_cpu_resume)
#endif