root/arch/powerpc/kernel/cpu_setup_44x.S

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * This file contains low level CPU setup functions.
   4  * Valentine Barshak <vbarshak@ru.mvista.com>
   5  * MontaVista Software, Inc (c) 2007
   6  *
   7  * Based on cpu_setup_6xx code by
   8  * Benjamin Herrenschmidt <benh@kernel.crashing.org>
   9  */
  10 
  11 #include <asm/processor.h>
  12 #include <asm/cputable.h>
  13 #include <asm/ppc_asm.h>
  14 
  15 _GLOBAL(__setup_cpu_440ep)
  16         b       __init_fpu_44x
  17 _GLOBAL(__setup_cpu_440epx)
  18         mflr    r4
  19         bl      __init_fpu_44x
  20         bl      __plb_disable_wrp
  21         bl      __fixup_440A_mcheck
  22         mtlr    r4
  23         blr
  24 _GLOBAL(__setup_cpu_440grx)
  25         mflr    r4
  26         bl      __plb_disable_wrp
  27         bl      __fixup_440A_mcheck
  28         mtlr    r4
  29         blr
  30 _GLOBAL(__setup_cpu_460ex)
  31 _GLOBAL(__setup_cpu_460gt)
  32 _GLOBAL(__setup_cpu_460sx)
  33 _GLOBAL(__setup_cpu_apm821xx)
  34         mflr    r4
  35         bl      __init_fpu_44x
  36         bl      __fixup_440A_mcheck
  37         mtlr    r4
  38         blr
  39 
  40 _GLOBAL(__setup_cpu_440x5)
  41 _GLOBAL(__setup_cpu_440gx)
  42 _GLOBAL(__setup_cpu_440spe)
  43         b       __fixup_440A_mcheck
  44 
  45 /* enable APU between CPU and FPU */
  46 _GLOBAL(__init_fpu_44x)
  47         mfspr   r3,SPRN_CCR0
  48         /* Clear DAPUIB flag in CCR0 */
  49         rlwinm  r3,r3,0,12,10
  50         mtspr   SPRN_CCR0,r3
  51         isync
  52         blr
  53 
  54 /*
  55  * Workaround for the incorrect write to DDR SDRAM errata.
  56  * The write address can be corrupted during writes to
  57  * DDR SDRAM when write pipelining is enabled on PLB0.
  58  * Disable write pipelining here.
  59  */
  60 #define DCRN_PLB4A0_ACR 0x81
  61 
  62 _GLOBAL(__plb_disable_wrp)
  63         mfdcr   r3,DCRN_PLB4A0_ACR
  64         /* clear WRP bit in PLB4A0_ACR */
  65         rlwinm  r3,r3,0,8,6
  66         mtdcr   DCRN_PLB4A0_ACR,r3
  67         isync
  68         blr
  69