xref: /openbmc/linux/arch/mips/kernel/csrc-bcm1480.c (revision 2cf1c348)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2000,2001,2004 Broadcom Corporation
4  */
5 #include <linux/clocksource.h>
6 #include <linux/sched_clock.h>
7 
8 #include <asm/addrspace.h>
9 #include <asm/io.h>
10 #include <asm/time.h>
11 
12 #include <asm/sibyte/bcm1480_regs.h>
13 #include <asm/sibyte/sb1250_regs.h>
14 #include <asm/sibyte/bcm1480_int.h>
15 #include <asm/sibyte/bcm1480_scd.h>
16 
17 #include <asm/sibyte/sb1250.h>
18 
19 static u64 bcm1480_hpt_read(struct clocksource *cs)
20 {
21 	return (u64) __raw_readq(IOADDR(A_SCD_ZBBUS_CYCLE_COUNT));
22 }
23 
24 struct clocksource bcm1480_clocksource = {
25 	.name	= "zbbus-cycles",
26 	.rating = 200,
27 	.read	= bcm1480_hpt_read,
28 	.mask	= CLOCKSOURCE_MASK(64),
29 	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
30 };
31 
32 static u64 notrace sb1480_read_sched_clock(void)
33 {
34 	return __raw_readq(IOADDR(A_SCD_ZBBUS_CYCLE_COUNT));
35 }
36 
37 void __init sb1480_clocksource_init(void)
38 {
39 	struct clocksource *cs = &bcm1480_clocksource;
40 	unsigned int plldiv;
41 	unsigned long zbbus;
42 
43 	plldiv = G_BCM1480_SYS_PLL_DIV(__raw_readq(IOADDR(A_SCD_SYSTEM_CFG)));
44 	zbbus = ((plldiv >> 1) * 50000000) + ((plldiv & 1) * 25000000);
45 	clocksource_register_hz(cs, zbbus);
46 
47 	sched_clock_register(sb1480_read_sched_clock, 64, zbbus);
48 }
49