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 19static int clk_state; 20static volatile unsigned char *clk_ctrl; 21void (*cpu_pwr_save)(void); 22 23static 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 33static 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 45static 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 */ 62static 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 94static void swift_clockstop(void) 95{ 96 if (!clk_ctrl) 97 return; 98 clk_ctrl[0] = 0; 99} 100 101void __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} 127