arch/mips/dec/wbflush.c

   1 /*
   2  * Setup the right wbflush routine for the different DECstations.
   3  *
   4  * Created with information from:
   5  *      DECstation 3100 Desktop Workstation Functional Specification
   6  *      DECstation 5000/200 KN02 System Module Functional Specification
   7  *      mipsel-linux-objdump --disassemble vmunix | grep "wbflush" :-)
   8  *
   9  * This file is subject to the terms and conditions of the GNU General Public
  10  * License.  See the file "COPYING" in the main directory of this archive
  11  * for more details.
  12  *
  13  * Copyright (C) 1998 Harald Koerfgen
  14  * Copyright (C) 2002 Maciej W. Rozycki
  15  */
  16
  17 #include <linux/init.h>
  18
  19 #include <asm/bootinfo.h>
  20 #include <asm/wbflush.h>
  21 #include <asm/barrier.h>
  22
  23 static void wbflush_kn01(void);
  24 static void wbflush_kn210(void);
  25 static void wbflush_mips(void);
  26
  27 void (*__wbflush) (void);
  28
  29 void __init wbflush_setup(void)
  30 {
  31         switch (mips_machtype) {
  32         case MACH_DS23100:
  33         case MACH_DS5000_200:   /* DS5000 3max */
  34                 __wbflush = wbflush_kn01;
  35                 break;
  36         case MACH_DS5100:       /* DS5100 MIPSMATE */
  37                 __wbflush = wbflush_kn210;
  38                 break;
  39         case MACH_DS5000_1XX:   /* DS5000/100 3min */
  40         case MACH_DS5000_XX:    /* Personal DS5000/2x */
  41         case MACH_DS5000_2X0:   /* DS5000/240 3max+ */
  42         case MACH_DS5900:       /* DS5900 bigmax */
  43         default:
  44                 __wbflush = wbflush_mips;
  45                 break;
  46         }
  47 }
  48
  49 /*
  50  * For the DS3100 and DS5000/200 the R2020/R3220 writeback buffer functions
  51  * as part of Coprocessor 0.
  52  */
  53 static void wbflush_kn01(void)
  54 {
  55     asm(".set\tpush\n\t"
  56         ".set\tnoreorder\n\t"
  57         "1:\tbc0f\t1b\n\t"
  58         "nop\n\t"
  59         ".set\tpop");
  60 }
  61
  62 /*
  63  * For the DS5100 the writeback buffer seems to be a part of Coprocessor 3.
  64  * But CP3 has to enabled first.
  65  */
  66 static void wbflush_kn210(void)
  67 {
  68     asm(".set\tpush\n\t"
  69         ".set\tnoreorder\n\t"
  70         "mfc0\t$2,$12\n\t"
  71         "lui\t$3,0x8000\n\t"
  72         "or\t$3,$2,$3\n\t"
  73         "mtc0\t$3,$12\n\t"
  74         "nop\n"
  75         "1:\tbc3f\t1b\n\t"
  76         "nop\n\t"
  77         "mtc0\t$2,$12\n\t"
  78         "nop\n\t"
  79         ".set\tpop"
  80         : : : "$2", "$3");
  81 }
  82
  83 /*
  84  * I/O ASIC systems use a standard writeback buffer that gets flushed
  85  * upon an uncached read.
  86  */
  87 static void wbflush_mips(void)
  88 {
  89         __fast_iob();
  90 }
  91
  92 #include <linux/module.h>
  93
  94 EXPORT_SYMBOL(__wbflush);