| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame^] | 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 | #include <linux/clocksource.h> |
| 15 | #include <linux/sched_clock.h> |
| 16 | |
| 17 | #include <asm/addrspace.h> |
| 18 | #include <asm/io.h> |
| 19 | #include <asm/time.h> |
| 20 | |
| 21 | #include <asm/sibyte/sb1250.h> |
| 22 | #include <asm/sibyte/sb1250_regs.h> |
| 23 | #include <asm/sibyte/sb1250_int.h> |
| 24 | #include <asm/sibyte/sb1250_scd.h> |
| 25 | |
| 26 | #define SB1250_HPT_NUM 3 |
| 27 | #define SB1250_HPT_VALUE M_SCD_TIMER_CNT /* max value */ |
| 28 | |
| 29 | /* |
| 30 | * The HPT is free running from SB1250_HPT_VALUE down to 0 then starts over |
| 31 | * again. |
| 32 | */ |
| 33 | static inline u64 sb1250_hpt_get_cycles(void) |
| 34 | { |
| 35 | unsigned int count; |
| 36 | void __iomem *addr; |
| 37 | |
| 38 | addr = IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CNT)); |
| 39 | count = G_SCD_TIMER_CNT(__raw_readq(addr)); |
| 40 | |
| 41 | return SB1250_HPT_VALUE - count; |
| 42 | } |
| 43 | |
| 44 | static u64 sb1250_hpt_read(struct clocksource *cs) |
| 45 | { |
| 46 | return sb1250_hpt_get_cycles(); |
| 47 | } |
| 48 | |
| 49 | struct clocksource bcm1250_clocksource = { |
| 50 | .name = "bcm1250-counter-3", |
| 51 | .rating = 200, |
| 52 | .read = sb1250_hpt_read, |
| 53 | .mask = CLOCKSOURCE_MASK(23), |
| 54 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, |
| 55 | }; |
| 56 | |
| 57 | static u64 notrace sb1250_read_sched_clock(void) |
| 58 | { |
| 59 | return sb1250_hpt_get_cycles(); |
| 60 | } |
| 61 | |
| 62 | void __init sb1250_clocksource_init(void) |
| 63 | { |
| 64 | struct clocksource *cs = &bcm1250_clocksource; |
| 65 | |
| 66 | /* Setup hpt using timer #3 but do not enable irq for it */ |
| 67 | __raw_writeq(0, |
| 68 | IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, |
| 69 | R_SCD_TIMER_CFG))); |
| 70 | __raw_writeq(SB1250_HPT_VALUE, |
| 71 | IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, |
| 72 | R_SCD_TIMER_INIT))); |
| 73 | __raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS, |
| 74 | IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, |
| 75 | R_SCD_TIMER_CFG))); |
| 76 | |
| 77 | clocksource_register_hz(cs, V_SCD_TIMER_FREQ); |
| 78 | |
| 79 | sched_clock_register(sb1250_read_sched_clock, 23, V_SCD_TIMER_FREQ); |
| 80 | } |