1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2000, 2001 Broadcom Corporation
4  */
5 #include <linux/clockchips.h>
6 #include <linux/interrupt.h>
7 #include <linux/irq.h>
8 #include <linux/percpu.h>
9 #include <linux/smp.h>
10 
11 #include <asm/addrspace.h>
12 #include <asm/io.h>
13 #include <asm/time.h>
14 
15 #include <asm/sibyte/sb1250.h>
16 #include <asm/sibyte/sb1250_regs.h>
17 #include <asm/sibyte/sb1250_int.h>
18 #include <asm/sibyte/sb1250_scd.h>
19 
20 #define IMR_IP2_VAL	K_INT_MAP_I0
21 #define IMR_IP3_VAL	K_INT_MAP_I1
22 #define IMR_IP4_VAL	K_INT_MAP_I2
23 
24 /*
25  * The general purpose timer ticks at 1MHz independent if
26  * the rest of the system
27  */
28 
sibyte_shutdown(struct clock_event_device * evt)29 static int sibyte_shutdown(struct clock_event_device *evt)
30 {
31 	void __iomem *cfg;
32 
33 	cfg = IOADDR(A_SCD_TIMER_REGISTER(smp_processor_id(), R_SCD_TIMER_CFG));
34 
35 	/* Stop the timer until we actually program a shot */
36 	__raw_writeq(0, cfg);
37 
38 	return 0;
39 }
40 
sibyte_set_periodic(struct clock_event_device * evt)41 static int sibyte_set_periodic(struct clock_event_device *evt)
42 {
43 	unsigned int cpu = smp_processor_id();
44 	void __iomem *cfg, *init;
45 
46 	cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
47 	init = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT));
48 
49 	__raw_writeq(0, cfg);
50 	__raw_writeq((V_SCD_TIMER_FREQ / HZ) - 1, init);
51 	__raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS, cfg);
52 
53 	return 0;
54 }
55 
sibyte_next_event(unsigned long delta,struct clock_event_device * cd)56 static int sibyte_next_event(unsigned long delta, struct clock_event_device *cd)
57 {
58 	unsigned int cpu = smp_processor_id();
59 	void __iomem *cfg, *init;
60 
61 	cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
62 	init = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT));
63 
64 	__raw_writeq(0, cfg);
65 	__raw_writeq(delta - 1, init);
66 	__raw_writeq(M_SCD_TIMER_ENABLE, cfg);
67 
68 	return 0;
69 }
70 
sibyte_counter_handler(int irq,void * dev_id)71 static irqreturn_t sibyte_counter_handler(int irq, void *dev_id)
72 {
73 	unsigned int cpu = smp_processor_id();
74 	struct clock_event_device *cd = dev_id;
75 	void __iomem *cfg;
76 	unsigned long tmode;
77 
78 	if (clockevent_state_periodic(cd))
79 		tmode = M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS;
80 	else
81 		tmode = 0;
82 
83 	/* ACK interrupt */
84 	cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
85 	____raw_writeq(tmode, cfg);
86 
87 	cd->event_handler(cd);
88 
89 	return IRQ_HANDLED;
90 }
91 
92 static DEFINE_PER_CPU(struct clock_event_device, sibyte_hpt_clockevent);
93 static DEFINE_PER_CPU(char [18], sibyte_hpt_name);
94 
sb1250_clockevent_init(void)95 void sb1250_clockevent_init(void)
96 {
97 	unsigned int cpu = smp_processor_id();
98 	unsigned int irq = K_INT_TIMER_0 + cpu;
99 	struct clock_event_device *cd = &per_cpu(sibyte_hpt_clockevent, cpu);
100 	unsigned char *name = per_cpu(sibyte_hpt_name, cpu);
101 	unsigned long flags = IRQF_PERCPU | IRQF_TIMER;
102 
103 	/* Only have 4 general purpose timers, and we use last one as hpt */
104 	BUG_ON(cpu > 2);
105 
106 	sprintf(name, "sb1250-counter-%d", cpu);
107 	cd->name		= name;
108 	cd->features		= CLOCK_EVT_FEAT_PERIODIC |
109 				  CLOCK_EVT_FEAT_ONESHOT;
110 	clockevent_set_clock(cd, V_SCD_TIMER_FREQ);
111 	cd->max_delta_ns	= clockevent_delta2ns(0x7fffff, cd);
112 	cd->max_delta_ticks	= 0x7fffff;
113 	cd->min_delta_ns	= clockevent_delta2ns(2, cd);
114 	cd->min_delta_ticks	= 2;
115 	cd->rating		= 200;
116 	cd->irq			= irq;
117 	cd->cpumask		= cpumask_of(cpu);
118 	cd->set_next_event	= sibyte_next_event;
119 	cd->set_state_shutdown	= sibyte_shutdown;
120 	cd->set_state_periodic	= sibyte_set_periodic;
121 	cd->set_state_oneshot	= sibyte_shutdown;
122 	clockevents_register_device(cd);
123 
124 	sb1250_mask_irq(cpu, irq);
125 
126 	/*
127 	 * Map the timer interrupt to IP[4] of this cpu
128 	 */
129 	__raw_writeq(IMR_IP4_VAL,
130 		     IOADDR(A_IMR_REGISTER(cpu, R_IMR_INTERRUPT_MAP_BASE) +
131 			    (irq << 3)));
132 
133 	sb1250_unmask_irq(cpu, irq);
134 
135 	irq_set_affinity(irq, cpumask_of(cpu));
136 	if (request_irq(irq, sibyte_counter_handler, flags, name, cd))
137 		pr_err("Failed to request irq %d (%s)\n", irq, name);
138 }
139