[PATCH] powerpc: trivial: modify comments to refer to new location of files

[~andy/linux] / arch / ppc / platforms / chrp_time.c

diff --git a/arch/ppc/platforms/chrp_time.c b/arch/ppc/platforms/chrp_time.c
index 29d074c305f05b532b4256b8ab8cb34b3df6480e..c8627770af139a9a0beddd844c2e9802fe93c465 100644 (file)
--- a/arch/ppc/platforms/chrp_time.c
+++ b/arch/ppc/platforms/chrp_time.c
@@ -1,6 +1,4 @@
 /*
- *  arch/ppc/platforms/chrp_time.c
- *
  *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
  *
  * Adapted for PowerPC (PReP) by Gary Thomas
@@ -163,13 +161,75 @@ unsigned long chrp_get_rtc_time(void)
        return mktime(year, mon, day, hour, min, sec);
 }
 
+/*
+ * Calibrate the decrementer frequency with the VIA timer 1.
+ */
+#define VIA_TIMER_FREQ_6       4700000 /* time 1 frequency * 6 */
+
+/* VIA registers */
+#define RS             0x200           /* skip between registers */
+#define T1CL           (4*RS)          /* Timer 1 ctr/latch (low 8 bits) */
+#define T1CH           (5*RS)          /* Timer 1 counter (high 8 bits) */
+#define T1LL           (6*RS)          /* Timer 1 latch (low 8 bits) */
+#define T1LH           (7*RS)          /* Timer 1 latch (high 8 bits) */
+#define ACR            (11*RS)         /* Auxiliary control register */
+#define IFR            (13*RS)         /* Interrupt flag register */
+
+/* Bits in ACR */
+#define T1MODE         0xc0            /* Timer 1 mode */
+#define T1MODE_CONT    0x40            /*  continuous interrupts */
+
+/* Bits in IFR and IER */
+#define T1_INT         0x40            /* Timer 1 interrupt */
+
+static int __init chrp_via_calibrate_decr(void)
+{
+       struct device_node *vias;
+       volatile unsigned char __iomem *via;
+       int count = VIA_TIMER_FREQ_6 / 100;
+       unsigned int dstart, dend;
+
+       vias = find_devices("via-cuda");
+       if (vias == 0)
+               vias = find_devices("via");
+       if (vias == 0 || vias->n_addrs == 0)
+               return 0;
+       via = ioremap(vias->addrs[0].address, vias->addrs[0].size);
+
+       /* set timer 1 for continuous interrupts */
+       out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT);
+       /* set the counter to a small value */
+       out_8(&via[T1CH], 2);
+       /* set the latch to `count' */
+       out_8(&via[T1LL], count);
+       out_8(&via[T1LH], count >> 8);
+       /* wait until it hits 0 */
+       while ((in_8(&via[IFR]) & T1_INT) == 0)
+               ;
+       dstart = get_dec();
+       /* clear the interrupt & wait until it hits 0 again */
+       in_8(&via[T1CL]);
+       while ((in_8(&via[IFR]) & T1_INT) == 0)
+               ;
+       dend = get_dec();
+
+       tb_ticks_per_jiffy = (dstart - dend) / ((6 * HZ)/100);
+       tb_to_us = mulhwu_scale_factor(dstart - dend, 60000);
+
+       printk(KERN_INFO "via_calibrate_decr: ticks per jiffy = %u (%u ticks)\n",
+              tb_ticks_per_jiffy, dstart - dend);
+
+       iounmap(via);
+       
+       return 1;
+}
 
 void __init chrp_calibrate_decr(void)
 {
        struct device_node *cpu;
        unsigned int freq, *fp;
 
-       if (via_calibrate_decr())
+       if (chrp_via_calibrate_decr())
                return;
 
        /*