root/arch/powerpc/kernel/cpu_setup_44x.S
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * This file contains low level CPU setup functions.
 * Valentine Barshak <vbarshak@ru.mvista.com>
 * MontaVista Software, Inc (c) 2007
 *
 * Based on cpu_setup_6xx code by
 * Benjamin Herrenschmidt <benh@kernel.crashing.org>
 */

#include <asm/processor.h>
#include <asm/cputable.h>
#include <asm/ppc_asm.h>

_GLOBAL(__setup_cpu_440ep)
        b       __init_fpu_44x
_GLOBAL(__setup_cpu_440epx)
        mflr    r4
        bl      __init_fpu_44x
        bl      __plb_disable_wrp
        bl      __fixup_440A_mcheck
        mtlr    r4
        blr
_GLOBAL(__setup_cpu_440grx)
        mflr    r4
        bl      __plb_disable_wrp
        bl      __fixup_440A_mcheck
        mtlr    r4
        blr
_GLOBAL(__setup_cpu_460ex)
_GLOBAL(__setup_cpu_460gt)
_GLOBAL(__setup_cpu_460sx)
_GLOBAL(__setup_cpu_apm821xx)
        mflr    r4
        bl      __init_fpu_44x
        bl      __fixup_440A_mcheck
        mtlr    r4
        blr

_GLOBAL(__setup_cpu_440x5)
_GLOBAL(__setup_cpu_440gx)
_GLOBAL(__setup_cpu_440spe)
        b       __fixup_440A_mcheck

/* enable APU between CPU and FPU */
_GLOBAL(__init_fpu_44x)
        mfspr   r3,SPRN_CCR0
        /* Clear DAPUIB flag in CCR0 */
        rlwinm  r3,r3,0,12,10
        mtspr   SPRN_CCR0,r3
        isync
        blr

/*
 * Workaround for the incorrect write to DDR SDRAM errata.
 * The write address can be corrupted during writes to
 * DDR SDRAM when write pipelining is enabled on PLB0.
 * Disable write pipelining here.
 */
#define DCRN_PLB4A0_ACR 0x81

_GLOBAL(__plb_disable_wrp)
        mfdcr   r3,DCRN_PLB4A0_ACR
        /* clear WRP bit in PLB4A0_ACR */
        rlwinm  r3,r3,0,8,6
        mtdcr   DCRN_PLB4A0_ACR,r3
        isync
        blr