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csrc-sb1250.c
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1 /*
2  * Copyright (C) 2000, 2001 Broadcom Corporation
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License
6  * as published by the Free Software Foundation; either version 2
7  * of the License, or (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17  */
18 #include <linux/clocksource.h>
19 
20 #include <asm/addrspace.h>
21 #include <asm/io.h>
22 #include <asm/time.h>
23 
24 #include <asm/sibyte/sb1250.h>
25 #include <asm/sibyte/sb1250_regs.h>
26 #include <asm/sibyte/sb1250_int.h>
27 #include <asm/sibyte/sb1250_scd.h>
28 
29 #define SB1250_HPT_NUM 3
30 #define SB1250_HPT_VALUE M_SCD_TIMER_CNT /* max value */
31 
32 /*
33  * The HPT is free running from SB1250_HPT_VALUE down to 0 then starts over
34  * again.
35  */
36 static cycle_t sb1250_hpt_read(struct clocksource *cs)
37 {
38  unsigned int count;
39 
41 
42  return SB1250_HPT_VALUE - count;
43 }
44 
46  .name = "bcm1250-counter-3",
47  .rating = 200,
48  .read = sb1250_hpt_read,
49  .mask = CLOCKSOURCE_MASK(23),
51 };
52 
54 {
56 
57  /* Setup hpt using timer #3 but do not enable irq for it */
58  __raw_writeq(0,
60  R_SCD_TIMER_CFG)));
66  R_SCD_TIMER_CFG)));
67 
68  clocksource_register_hz(cs, V_SCD_TIMER_FREQ);
69 }