root/arch/sparc/kernel/tadpole.c

/* */

DEFINITIONS

1. ldphys
2. clk_init
3. clk_slow
4. tsu_clockstop
5. swift_clockstop
6. clock_stop_probe

   1 /* tadpole.c: Probing for the tadpole clock stopping h/w at boot time.
   2  *
   3  * Copyright (C) 1996 David Redman (djhr@tadpole.co.uk)
   4  */
   5 
   6 #include <linux/string.h>
   7 
   8 #include <asm/asi.h>
   9 #include <asm/oplib.h>
  10 #include <asm/io.h>
  11 
  12 #define MACIO_SCSI_CSR_ADDR     0x78400000
  13 #define MACIO_EN_DMA            0x00000200
  14 #define CLOCK_INIT_DONE         1
  15 
  16 static int clk_state;
  17 static volatile unsigned char *clk_ctrl;
  18 void (*cpu_pwr_save)(void);
  19 
  20 static inline unsigned int ldphys(unsigned int addr)
     /*  */
  21 {
  22         unsigned long data;
  23     
  24         __asm__ __volatile__("\n\tlda [%1] %2, %0\n\t" : 
  25                              "=r" (data) :
  26                              "r" (addr), "i" (ASI_M_BYPASS));
  27         return data;
  28 }
  29 
  30 static void clk_init(void)
     /*  */
  31 {
  32         __asm__ __volatile__("mov 0x6c, %%g1\n\t"
  33                              "mov 0x4c, %%g2\n\t"
  34                              "mov 0xdf, %%g3\n\t"
  35                              "stb %%g1, [%0+3]\n\t"
  36                              "stb %%g2, [%0+3]\n\t"
  37                              "stb %%g3, [%0+3]\n\t" : :
  38                              "r" (clk_ctrl) :
  39                              "g1", "g2", "g3");
  40 }
  41 
  42 static void clk_slow(void)
     /*  */
  43 {
  44         __asm__ __volatile__("mov 0xcc, %%g2\n\t"
  45                              "mov 0x4c, %%g3\n\t"
  46                              "mov 0xcf, %%g4\n\t"
  47                              "mov 0xdf, %%g5\n\t"
  48                              "stb %%g2, [%0+3]\n\t"
  49                              "stb %%g3, [%0+3]\n\t"
  50                              "stb %%g4, [%0+3]\n\t"
  51                              "stb %%g5, [%0+3]\n\t" : :
  52                              "r" (clk_ctrl) :
  53                              "g2", "g3", "g4", "g5");
  54 }
  55 
  56 static void tsu_clockstop(void)
     /*  */
  57 {
  58         unsigned int mcsr;
  59         unsigned long flags;
  60 
  61         if (!clk_ctrl)
  62                 return;
  63         if (!(clk_state & CLOCK_INIT_DONE)) {
  64                 save_flags(flags); cli();
  65                 clk_init();
  66                 clk_state |= CLOCK_INIT_DONE;       /* all done */
  67                 restore_flags(flags);
  68                 return;
  69         }
  70         if (!(clk_ctrl[2] & 1))
  71                 return;               /* no speed up yet */
  72 
  73         save_flags(flags); cli();
  74 
  75         /* if SCSI DMA in progress, don't slow clock */
  76         mcsr = ldphys(MACIO_SCSI_CSR_ADDR);
  77         if ((mcsr&MACIO_EN_DMA) != 0) {
  78                 restore_flags(flags);
  79                 return;
  80         }
  81         /* TODO... the minimum clock setting ought to increase the
  82          * memory refresh interval..
  83          */
  84         clk_slow();
  85         restore_flags(flags);
  86 }
  87 
  88 static void swift_clockstop(void)
     /*  */
  89 {
  90         if (!clk_ctrl)
  91                 return;
  92         clk_ctrl[0] = 0;
  93 }
  94 
  95 void clock_stop_probe(void)
     /*  */
  96 {
  97         unsigned int node, clk_nd;
  98         char name[20];
  99     
 100         prom_getstring(prom_root_node, "name", name, sizeof(name));
 101         if (strncmp(name, "Tadpole", 7))
 102                 return;
 103         node = prom_getchild(prom_root_node);
 104         node = prom_searchsiblings(node, "obio");
 105         node = prom_getchild(node);
 106         clk_nd = prom_searchsiblings(node, "clk-ctrl");
 107         if (!clk_nd)
 108                 return;
 109         printk("Clock Stopping h/w detected... ");
 110         clk_ctrl = (char *) prom_getint(clk_nd, "address");
 111         clk_state = 0;
 112         if (name[10] == '\0') {
 113                 cpu_pwr_save = tsu_clockstop;
 114                 printk("enabled (S3)\n");
 115         } else if ((name[10] == 'X') || (name[10] == 'G')) {
 116                 cpu_pwr_save = swift_clockstop;
 117                 printk("enabled (%s)\n",name+7);
 118         } else
 119                 printk("disabled %s\n",name+7);
 120 }

/* */