arch/powerpc/platforms/powermac/time.c

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
pmac_time_init
smu_get_time
pmac_get_boot_time
pmac_get_rtc_time
pmac_set_rtc_time
via_calibrate_decr
pmac_calibrate_decr
   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Support for periodic interrupts (100 per second) and for getting
   4  * the current time from the RTC on Power Macintoshes.
   5  *
   6  * We use the decrementer register for our periodic interrupts.
   7  *
   8  * Paul Mackerras       August 1996.
   9  * Copyright (C) 1996 Paul Mackerras.
  10  * Copyright (C) 2003-2005 Benjamin Herrenschmidt.
  11  *
  12  */
  13 #include <linux/errno.h>
  14 #include <linux/sched.h>
  15 #include <linux/kernel.h>
  16 #include <linux/param.h>
  17 #include <linux/string.h>
  18 #include <linux/mm.h>
  19 #include <linux/init.h>
  20 #include <linux/time.h>
  21 #include <linux/adb.h>
  22 #include <linux/cuda.h>
  23 #include <linux/pmu.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/hardirq.h>
  26 #include <linux/rtc.h>
  27 
  28 #include <asm/sections.h>
  29 #include <asm/prom.h>
  30 #include <asm/io.h>
  31 #include <asm/pgtable.h>
  32 #include <asm/machdep.h>
  33 #include <asm/time.h>
  34 #include <asm/nvram.h>
  35 #include <asm/smu.h>
  36 
  37 #include "pmac.h"
  38 
  39 #undef DEBUG
  40 
  41 #ifdef DEBUG
  42 #define DBG(x...) printk(x)
  43 #else
  44 #define DBG(x...)
  45 #endif
  46 
  47 /*
  48  * Calibrate the decrementer frequency with the VIA timer 1.
  49  */
  50 #define VIA_TIMER_FREQ_6        4700000 /* time 1 frequency * 6 */
  51 
  52 /* VIA registers */
  53 #define RS              0x200           /* skip between registers */
  54 #define T1CL            (4*RS)          /* Timer 1 ctr/latch (low 8 bits) */
  55 #define T1CH            (5*RS)          /* Timer 1 counter (high 8 bits) */
  56 #define T1LL            (6*RS)          /* Timer 1 latch (low 8 bits) */
  57 #define T1LH            (7*RS)          /* Timer 1 latch (high 8 bits) */
  58 #define ACR             (11*RS)         /* Auxiliary control register */
  59 #define IFR             (13*RS)         /* Interrupt flag register */
  60 
  61 /* Bits in ACR */
  62 #define T1MODE          0xc0            /* Timer 1 mode */
  63 #define T1MODE_CONT     0x40            /*  continuous interrupts */
  64 
  65 /* Bits in IFR and IER */
  66 #define T1_INT          0x40            /* Timer 1 interrupt */
  67 
  68 long __init pmac_time_init(void)
  69 {
  70         s32 delta = 0;
  71 #if defined(CONFIG_NVRAM) && defined(CONFIG_PPC32)
  72         int dst;
  73         
  74         delta = ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x9)) << 16;
  75         delta |= ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xa)) << 8;
  76         delta |= pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xb);
  77         if (delta & 0x00800000UL)
  78                 delta |= 0xFF000000UL;
  79         dst = ((pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x8) & 0x80) != 0);
  80         printk("GMT Delta read from XPRAM: %d minutes, DST: %s\n", delta/60,
  81                 dst ? "on" : "off");
  82 #endif
  83         return delta;
  84 }
  85 
  86 #ifdef CONFIG_PMAC_SMU
  87 static time64_t smu_get_time(void)
  88 {
  89         struct rtc_time tm;
  90 
  91         if (smu_get_rtc_time(&tm, 1))
  92                 return 0;
  93         return rtc_tm_to_time64(&tm);
  94 }
  95 #endif
  96 
  97 /* Can't be __init, it's called when suspending and resuming */
  98 time64_t pmac_get_boot_time(void)
  99 {
 100         /* Get the time from the RTC, used only at boot time */
 101         switch (sys_ctrler) {
 102 #ifdef CONFIG_ADB_CUDA
 103         case SYS_CTRLER_CUDA:
 104                 return cuda_get_time();
 105 #endif
 106 #ifdef CONFIG_ADB_PMU
 107         case SYS_CTRLER_PMU:
 108                 return pmu_get_time();
 109 #endif
 110 #ifdef CONFIG_PMAC_SMU
 111         case SYS_CTRLER_SMU:
 112                 return smu_get_time();
 113 #endif
 114         default:
 115                 return 0;
 116         }
 117 }
 118 
 119 void pmac_get_rtc_time(struct rtc_time *tm)
 120 {
 121         /* Get the time from the RTC, used only at boot time */
 122         switch (sys_ctrler) {
 123 #ifdef CONFIG_ADB_CUDA
 124         case SYS_CTRLER_CUDA:
 125                 rtc_time64_to_tm(cuda_get_time(), tm);
 126                 break;
 127 #endif
 128 #ifdef CONFIG_ADB_PMU
 129         case SYS_CTRLER_PMU:
 130                 rtc_time64_to_tm(pmu_get_time(), tm);
 131                 break;
 132 #endif
 133 #ifdef CONFIG_PMAC_SMU
 134         case SYS_CTRLER_SMU:
 135                 smu_get_rtc_time(tm, 1);
 136                 break;
 137 #endif
 138         default:
 139                 ;
 140         }
 141 }
 142 
 143 int pmac_set_rtc_time(struct rtc_time *tm)
 144 {
 145         switch (sys_ctrler) {
 146 #ifdef CONFIG_ADB_CUDA
 147         case SYS_CTRLER_CUDA:
 148                 return cuda_set_rtc_time(tm);
 149 #endif
 150 #ifdef CONFIG_ADB_PMU
 151         case SYS_CTRLER_PMU:
 152                 return pmu_set_rtc_time(tm);
 153 #endif
 154 #ifdef CONFIG_PMAC_SMU
 155         case SYS_CTRLER_SMU:
 156                 return smu_set_rtc_time(tm, 1);
 157 #endif
 158         default:
 159                 return -ENODEV;
 160         }
 161 }
 162 
 163 #ifdef CONFIG_PPC32
 164 /*
 165  * Calibrate the decrementer register using VIA timer 1.
 166  * This is used both on powermacs and CHRP machines.
 167  */
 168 static int __init via_calibrate_decr(void)
 169 {
 170         struct device_node *vias;
 171         volatile unsigned char __iomem *via;
 172         int count = VIA_TIMER_FREQ_6 / 100;
 173         unsigned int dstart, dend;
 174         struct resource rsrc;
 175 
 176         vias = of_find_node_by_name(NULL, "via-cuda");
 177         if (vias == NULL)
 178                 vias = of_find_node_by_name(NULL, "via-pmu");
 179         if (vias == NULL)
 180                 vias = of_find_node_by_name(NULL, "via");
 181         if (vias == NULL || of_address_to_resource(vias, 0, &rsrc)) {
 182                 of_node_put(vias);
 183                 return 0;
 184         }
 185         of_node_put(vias);
 186         via = ioremap(rsrc.start, resource_size(&rsrc));
 187         if (via == NULL) {
 188                 printk(KERN_ERR "Failed to map VIA for timer calibration !\n");
 189                 return 0;
 190         }
 191 
 192         /* set timer 1 for continuous interrupts */
 193         out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT);
 194         /* set the counter to a small value */
 195         out_8(&via[T1CH], 2);
 196         /* set the latch to `count' */
 197         out_8(&via[T1LL], count);
 198         out_8(&via[T1LH], count >> 8);
 199         /* wait until it hits 0 */
 200         while ((in_8(&via[IFR]) & T1_INT) == 0)
 201                 ;
 202         dstart = get_dec();
 203         /* clear the interrupt & wait until it hits 0 again */
 204         in_8(&via[T1CL]);
 205         while ((in_8(&via[IFR]) & T1_INT) == 0)
 206                 ;
 207         dend = get_dec();
 208 
 209         ppc_tb_freq = (dstart - dend) * 100 / 6;
 210 
 211         iounmap(via);
 212 
 213         return 1;
 214 }
 215 #endif
 216 
 217 /*
 218  * Query the OF and get the decr frequency.
 219  */
 220 void __init pmac_calibrate_decr(void)
 221 {
 222         generic_calibrate_decr();
 223 
 224 #ifdef CONFIG_PPC32
 225         /* We assume MacRISC2 machines have correct device-tree
 226          * calibration. That's better since the VIA itself seems
 227          * to be slightly off. --BenH
 228          */
 229         if (!of_machine_is_compatible("MacRISC2") &&
 230             !of_machine_is_compatible("MacRISC3") &&
 231             !of_machine_is_compatible("MacRISC4"))
 232                 if (via_calibrate_decr())
 233                         return;
 234 
 235         /* Special case: QuickSilver G4s seem to have a badly calibrated
 236          * timebase-frequency in OF, VIA is much better on these. We should
 237          * probably implement calibration based on the KL timer on these
 238          * machines anyway... -BenH
 239          */
 240         if (of_machine_is_compatible("PowerMac3,5"))
 241                 if (via_calibrate_decr())
 242                         return;
 243 #endif
 244 }
/* [<][>][^][v][top][bottom][index][help] */
root/arch/powerpc/platforms/powermac/time.c

DEFINITIONS
