Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm
[linux-2.6] / arch / sparc / kernel / tadpole.c
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 #include <linux/kernel.h>
8 #include <linux/sched.h>
9 #include <linux/init.h>
10
11 #include <asm/asi.h>
12 #include <asm/oplib.h>
13 #include <asm/io.h>
14
15 #define MACIO_SCSI_CSR_ADDR     0x78400000
16 #define MACIO_EN_DMA            0x00000200
17 #define CLOCK_INIT_DONE         1
18
19 static int clk_state;
20 static volatile unsigned char *clk_ctrl;
21 void (*cpu_pwr_save)(void);
22
23 static inline unsigned int ldphys(unsigned int addr)
24 {
25         unsigned long data;
26     
27         __asm__ __volatile__("\n\tlda [%1] %2, %0\n\t" : 
28                              "=r" (data) :
29                              "r" (addr), "i" (ASI_M_BYPASS));
30         return data;
31 }
32
33 static void clk_init(void)
34 {
35         __asm__ __volatile__("mov 0x6c, %%g1\n\t"
36                              "mov 0x4c, %%g2\n\t"
37                              "mov 0xdf, %%g3\n\t"
38                              "stb %%g1, [%0+3]\n\t"
39                              "stb %%g2, [%0+3]\n\t"
40                              "stb %%g3, [%0+3]\n\t" : :
41                              "r" (clk_ctrl) :
42                              "g1", "g2", "g3");
43 }
44
45 static void clk_slow(void)
46 {
47         __asm__ __volatile__("mov 0xcc, %%g2\n\t"
48                              "mov 0x4c, %%g3\n\t"
49                              "mov 0xcf, %%g4\n\t"
50                              "mov 0xdf, %%g5\n\t"
51                              "stb %%g2, [%0+3]\n\t"
52                              "stb %%g3, [%0+3]\n\t"
53                              "stb %%g4, [%0+3]\n\t"
54                              "stb %%g5, [%0+3]\n\t" : :
55                              "r" (clk_ctrl) :
56                              "g2", "g3", "g4", "g5");
57 }
58
59 /*
60  * Tadpole is guaranteed to be UP, using local_irq_save.
61  */
62 static void tsu_clockstop(void)
63 {
64         unsigned int mcsr;
65         unsigned long flags;
66
67         if (!clk_ctrl)
68                 return;
69         if (!(clk_state & CLOCK_INIT_DONE)) {
70                 local_irq_save(flags);
71                 clk_init();
72                 clk_state |= CLOCK_INIT_DONE;       /* all done */
73                 local_irq_restore(flags);
74                 return;
75         }
76         if (!(clk_ctrl[2] & 1))
77                 return;               /* no speed up yet */
78
79         local_irq_save(flags);
80
81         /* if SCSI DMA in progress, don't slow clock */
82         mcsr = ldphys(MACIO_SCSI_CSR_ADDR);
83         if ((mcsr&MACIO_EN_DMA) != 0) {
84                 local_irq_restore(flags);
85                 return;
86         }
87         /* TODO... the minimum clock setting ought to increase the
88          * memory refresh interval..
89          */
90         clk_slow();
91         local_irq_restore(flags);
92 }
93
94 static void swift_clockstop(void)
95 {
96         if (!clk_ctrl)
97                 return;
98         clk_ctrl[0] = 0;
99 }
100
101 void __init clock_stop_probe(void)
102 {
103         unsigned int node, clk_nd;
104         char name[20];
105     
106         prom_getstring(prom_root_node, "name", name, sizeof(name));
107         if (strncmp(name, "Tadpole", 7))
108                 return;
109         node = prom_getchild(prom_root_node);
110         node = prom_searchsiblings(node, "obio");
111         node = prom_getchild(node);
112         clk_nd = prom_searchsiblings(node, "clk-ctrl");
113         if (!clk_nd)
114                 return;
115         printk("Clock Stopping h/w detected... ");
116         clk_ctrl = (char *) prom_getint(clk_nd, "address");
117         clk_state = 0;
118         if (name[10] == '\0') {
119                 cpu_pwr_save = tsu_clockstop;
120                 printk("enabled (S3)\n");
121         } else if ((name[10] == 'X') || (name[10] == 'G')) {
122                 cpu_pwr_save = swift_clockstop;
123                 printk("enabled (%s)\n",name+7);
124         } else
125                 printk("disabled %s\n",name+7);
126 }