1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C) 2000, 2001 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/sb1250.h> 13 #include <asm/sibyte/sb1250_regs.h> 14 #include <asm/sibyte/sb1250_int.h> 15 #include <asm/sibyte/sb1250_scd.h> 16 17 #define SB1250_HPT_NUM 3 18 #define SB1250_HPT_VALUE M_SCD_TIMER_CNT /* max value */ 19 20 /* 21 * The HPT is free running from SB1250_HPT_VALUE down to 0 then starts over 22 * again. 23 */ 24 static inline u64 sb1250_hpt_get_cycles(void) 25 { 26 unsigned int count; 27 void __iomem *addr; 28 29 addr = IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CNT)); 30 count = G_SCD_TIMER_CNT(__raw_readq(addr)); 31 32 return SB1250_HPT_VALUE - count; 33 } 34 35 static u64 sb1250_hpt_read(struct clocksource *cs) 36 { 37 return sb1250_hpt_get_cycles(); 38 } 39 40 struct clocksource bcm1250_clocksource = { 41 .name = "bcm1250-counter-3", 42 .rating = 200, 43 .read = sb1250_hpt_read, 44 .mask = CLOCKSOURCE_MASK(23), 45 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 46 }; 47 48 static u64 notrace sb1250_read_sched_clock(void) 49 { 50 return sb1250_hpt_get_cycles(); 51 } 52 53 void __init sb1250_clocksource_init(void) 54 { 55 struct clocksource *cs = &bcm1250_clocksource; 56 57 /* Setup hpt using timer #3 but do not enable irq for it */ 58 __raw_writeq(0, 59 IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, 60 R_SCD_TIMER_CFG))); 61 __raw_writeq(SB1250_HPT_VALUE, 62 IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, 63 R_SCD_TIMER_INIT))); 64 __raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS, 65 IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, 66 R_SCD_TIMER_CFG))); 67 68 clocksource_register_hz(cs, V_SCD_TIMER_FREQ); 69 70 sched_clock_register(sb1250_read_sched_clock, 23, V_SCD_TIMER_FREQ); 71 } 72