Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * This file is subject to the terms and conditions of the GNU General Public |
| 3 | * License. See the file "COPYING" in the main directory of this archive |
| 4 | * for more details. |
| 5 | * |
| 6 | * Time operations for IP22 machines. Original code may come from |
| 7 | * Ralf Baechle or David S. Miller (sorry guys, i'm really not sure) |
| 8 | * |
| 9 | * Copyright (C) 2001 by Ladislav Michl |
Ralf Baechle | 54d0a21 | 2006-07-09 21:38:56 +0100 | [diff] [blame] | 10 | * Copyright (C) 2003, 06 Ralf Baechle (ralf@linux-mips.org) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 11 | */ |
| 12 | #include <linux/bcd.h> |
Ralf Baechle | 334955e | 2011-06-01 19:04:57 +0100 | [diff] [blame] | 13 | #include <linux/i8253.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 14 | #include <linux/init.h> |
Ralf Baechle | 046f8f7 | 2006-07-09 20:49:41 +0100 | [diff] [blame] | 15 | #include <linux/irq.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | #include <linux/kernel.h> |
| 17 | #include <linux/interrupt.h> |
| 18 | #include <linux/kernel_stat.h> |
| 19 | #include <linux/time.h> |
Wu Zhangjin | 8f99a16 | 2009-11-20 20:34:33 +0800 | [diff] [blame] | 20 | #include <linux/ftrace.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | |
| 22 | #include <asm/cpu.h> |
| 23 | #include <asm/mipsregs.h> |
| 24 | #include <asm/io.h> |
| 25 | #include <asm/irq.h> |
| 26 | #include <asm/time.h> |
| 27 | #include <asm/sgialib.h> |
| 28 | #include <asm/sgi/ioc.h> |
| 29 | #include <asm/sgi/hpc3.h> |
| 30 | #include <asm/sgi/ip22.h> |
| 31 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | static unsigned long dosample(void) |
| 33 | { |
| 34 | u32 ct0, ct1; |
Ralf Baechle | 6fd78fc | 2011-03-29 11:00:44 +0200 | [diff] [blame] | 35 | u8 msb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | |
| 37 | /* Start the counter. */ |
| 38 | sgint->tcword = (SGINT_TCWORD_CNT2 | SGINT_TCWORD_CALL | |
| 39 | SGINT_TCWORD_MRGEN); |
| 40 | sgint->tcnt2 = SGINT_TCSAMP_COUNTER & 0xff; |
| 41 | sgint->tcnt2 = SGINT_TCSAMP_COUNTER >> 8; |
| 42 | |
| 43 | /* Get initial counter invariant */ |
| 44 | ct0 = read_c0_count(); |
| 45 | |
| 46 | /* Latch and spin until top byte of counter2 is zero */ |
| 47 | do { |
Ralf Baechle | 78709b9d | 2007-04-26 15:46:24 +0100 | [diff] [blame] | 48 | writeb(SGINT_TCWORD_CNT2 | SGINT_TCWORD_CLAT, &sgint->tcword); |
Ralf Baechle | 6fd78fc | 2011-03-29 11:00:44 +0200 | [diff] [blame] | 49 | (void) readb(&sgint->tcnt2); |
Ralf Baechle | 78709b9d | 2007-04-26 15:46:24 +0100 | [diff] [blame] | 50 | msb = readb(&sgint->tcnt2); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 51 | ct1 = read_c0_count(); |
| 52 | } while (msb); |
| 53 | |
| 54 | /* Stop the counter. */ |
Thomas Bogendoerfer | 01e9943 | 2007-09-11 12:43:55 +0200 | [diff] [blame] | 55 | writeb(SGINT_TCWORD_CNT2 | SGINT_TCWORD_CALL | SGINT_TCWORD_MSWST, |
| 56 | &sgint->tcword); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 57 | /* |
| 58 | * Return the difference, this is how far the r4k counter increments |
| 59 | * for every 1/HZ seconds. We round off the nearest 1 MHz of master |
| 60 | * clock (= 1000000 / HZ / 2). |
| 61 | */ |
Ralf Baechle | 78709b9d | 2007-04-26 15:46:24 +0100 | [diff] [blame] | 62 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | return (ct1 - ct0) / (500000/HZ) * (500000/HZ); |
| 64 | } |
| 65 | |
| 66 | /* |
| 67 | * Here we need to calibrate the cycle counter to at least be close. |
| 68 | */ |
Ralf Baechle | 4b55048 | 2007-10-11 23:46:08 +0100 | [diff] [blame] | 69 | __init void plat_time_init(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 70 | { |
| 71 | unsigned long r4k_ticks[3]; |
| 72 | unsigned long r4k_tick; |
| 73 | |
Ralf Baechle | 42a3b4f | 2005-09-03 15:56:17 -0700 | [diff] [blame] | 74 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 75 | * Figure out the r4k offset, the algorithm is very simple and works in |
| 76 | * _all_ cases as long as the 8254 counter register itself works ok (as |
| 77 | * an interrupt driving timer it does not because of bug, this is why |
| 78 | * we are using the onchip r4k counter/compare register to serve this |
| 79 | * purpose, but for r4k_offset calculation it will work ok for us). |
| 80 | * There are other very complicated ways of performing this calculation |
| 81 | * but this one works just fine so I am not going to futz around. ;-) |
| 82 | */ |
| 83 | printk(KERN_INFO "Calibrating system timer... "); |
| 84 | dosample(); /* Prime cache. */ |
| 85 | dosample(); /* Prime cache. */ |
| 86 | /* Zero is NOT an option. */ |
| 87 | do { |
| 88 | r4k_ticks[0] = dosample(); |
| 89 | } while (!r4k_ticks[0]); |
| 90 | do { |
| 91 | r4k_ticks[1] = dosample(); |
| 92 | } while (!r4k_ticks[1]); |
| 93 | |
| 94 | if (r4k_ticks[0] != r4k_ticks[1]) { |
| 95 | printk("warning: timer counts differ, retrying... "); |
| 96 | r4k_ticks[2] = dosample(); |
| 97 | if (r4k_ticks[2] == r4k_ticks[0] |
| 98 | || r4k_ticks[2] == r4k_ticks[1]) |
| 99 | r4k_tick = r4k_ticks[2]; |
| 100 | else { |
| 101 | printk("disagreement, using average... "); |
| 102 | r4k_tick = (r4k_ticks[0] + r4k_ticks[1] |
| 103 | + r4k_ticks[2]) / 3; |
| 104 | } |
| 105 | } else |
| 106 | r4k_tick = r4k_ticks[0]; |
| 107 | |
| 108 | printk("%d [%d.%04d MHz CPU]\n", (int) r4k_tick, |
| 109 | (int) (r4k_tick / (500000 / HZ)), |
| 110 | (int) (r4k_tick % (500000 / HZ))); |
| 111 | |
| 112 | mips_hpt_frequency = r4k_tick * HZ; |
Ralf Baechle | d865bea | 2007-10-11 23:46:10 +0100 | [diff] [blame] | 113 | |
| 114 | if (ip22_is_fullhouse()) |
| 115 | setup_pit_timer(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 116 | } |
| 117 | |
| 118 | /* Generic SGI handler for (spurious) 8254 interrupts */ |
Wu Zhangjin | 8f99a16 | 2009-11-20 20:34:33 +0800 | [diff] [blame] | 119 | void __irq_entry indy_8254timer_irq(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | { |
| 121 | int irq = SGI_8254_0_IRQ; |
| 122 | ULONG cnt; |
| 123 | char c; |
| 124 | |
| 125 | irq_enter(); |
Mike Travis | d2287f5 | 2009-01-14 15:43:54 -0800 | [diff] [blame] | 126 | kstat_incr_irqs_this_cpu(irq, irq_to_desc(irq)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 127 | printk(KERN_ALERT "Oops, got 8254 interrupt.\n"); |
| 128 | ArcRead(0, &c, 1, &cnt); |
| 129 | ArcEnterInteractiveMode(); |
| 130 | irq_exit(); |
| 131 | } |