1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2000, 2001, 2002, 2003 Broadcom Corporation
4  */
5 #include <linux/kernel.h>
6 #include <linux/init.h>
7 #include <linux/linkage.h>
8 #include <linux/interrupt.h>
9 #include <linux/spinlock.h>
10 #include <linux/smp.h>
11 #include <linux/mm.h>
12 #include <linux/kernel_stat.h>
13 
14 #include <asm/errno.h>
15 #include <asm/signal.h>
16 #include <asm/time.h>
17 #include <asm/io.h>
18 
19 #include <asm/sibyte/sb1250_regs.h>
20 #include <asm/sibyte/sb1250_int.h>
21 #include <asm/sibyte/sb1250_uart.h>
22 #include <asm/sibyte/sb1250_scd.h>
23 #include <asm/sibyte/sb1250.h>
24 
25 /*
26  * These are the routines that handle all the low level interrupt stuff.
27  * Actions handled here are: initialization of the interrupt map, requesting of
28  * interrupt lines by handlers, dispatching if interrupts to handlers, probing
29  * for interrupt lines
30  */
31 
32 #ifdef CONFIG_SIBYTE_HAS_LDT
33 extern unsigned long ldt_eoi_space;
34 #endif
35 
36 /* Store the CPU id (not the logical number) */
37 int sb1250_irq_owner[SB1250_NR_IRQS];
38 
39 static DEFINE_RAW_SPINLOCK(sb1250_imr_lock);
40 
sb1250_mask_irq(int cpu,int irq)41 void sb1250_mask_irq(int cpu, int irq)
42 {
43 	unsigned long flags;
44 	u64 cur_ints;
45 
46 	raw_spin_lock_irqsave(&sb1250_imr_lock, flags);
47 	cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
48 					R_IMR_INTERRUPT_MASK));
49 	cur_ints |= (((u64) 1) << irq);
50 	____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
51 					R_IMR_INTERRUPT_MASK));
52 	raw_spin_unlock_irqrestore(&sb1250_imr_lock, flags);
53 }
54 
sb1250_unmask_irq(int cpu,int irq)55 void sb1250_unmask_irq(int cpu, int irq)
56 {
57 	unsigned long flags;
58 	u64 cur_ints;
59 
60 	raw_spin_lock_irqsave(&sb1250_imr_lock, flags);
61 	cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
62 					R_IMR_INTERRUPT_MASK));
63 	cur_ints &= ~(((u64) 1) << irq);
64 	____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
65 					R_IMR_INTERRUPT_MASK));
66 	raw_spin_unlock_irqrestore(&sb1250_imr_lock, flags);
67 }
68 
69 #ifdef CONFIG_SMP
sb1250_set_affinity(struct irq_data * d,const struct cpumask * mask,bool force)70 static int sb1250_set_affinity(struct irq_data *d, const struct cpumask *mask,
71 			       bool force)
72 {
73 	int i = 0, old_cpu, cpu, int_on;
74 	unsigned int irq = d->irq;
75 	u64 cur_ints;
76 	unsigned long flags;
77 
78 	i = cpumask_first_and(mask, cpu_online_mask);
79 
80 	/* Convert logical CPU to physical CPU */
81 	cpu = cpu_logical_map(i);
82 
83 	/* Protect against other affinity changers and IMR manipulation */
84 	raw_spin_lock_irqsave(&sb1250_imr_lock, flags);
85 
86 	/* Swizzle each CPU's IMR (but leave the IP selection alone) */
87 	old_cpu = sb1250_irq_owner[irq];
88 	cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(old_cpu) +
89 					R_IMR_INTERRUPT_MASK));
90 	int_on = !(cur_ints & (((u64) 1) << irq));
91 	if (int_on) {
92 		/* If it was on, mask it */
93 		cur_ints |= (((u64) 1) << irq);
94 		____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(old_cpu) +
95 					R_IMR_INTERRUPT_MASK));
96 	}
97 	sb1250_irq_owner[irq] = cpu;
98 	if (int_on) {
99 		/* unmask for the new CPU */
100 		cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
101 					R_IMR_INTERRUPT_MASK));
102 		cur_ints &= ~(((u64) 1) << irq);
103 		____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
104 					R_IMR_INTERRUPT_MASK));
105 	}
106 	raw_spin_unlock_irqrestore(&sb1250_imr_lock, flags);
107 
108 	return 0;
109 }
110 #endif
111 
disable_sb1250_irq(struct irq_data * d)112 static void disable_sb1250_irq(struct irq_data *d)
113 {
114 	unsigned int irq = d->irq;
115 
116 	sb1250_mask_irq(sb1250_irq_owner[irq], irq);
117 }
118 
enable_sb1250_irq(struct irq_data * d)119 static void enable_sb1250_irq(struct irq_data *d)
120 {
121 	unsigned int irq = d->irq;
122 
123 	sb1250_unmask_irq(sb1250_irq_owner[irq], irq);
124 }
125 
126 
ack_sb1250_irq(struct irq_data * d)127 static void ack_sb1250_irq(struct irq_data *d)
128 {
129 	unsigned int irq = d->irq;
130 #ifdef CONFIG_SIBYTE_HAS_LDT
131 	u64 pending;
132 
133 	/*
134 	 * If the interrupt was an HT interrupt, now is the time to
135 	 * clear it.  NOTE: we assume the HT bridge was set up to
136 	 * deliver the interrupts to all CPUs (which makes affinity
137 	 * changing easier for us)
138 	 */
139 	pending = __raw_readq(IOADDR(A_IMR_REGISTER(sb1250_irq_owner[irq],
140 						    R_IMR_LDT_INTERRUPT)));
141 	pending &= ((u64)1 << (irq));
142 	if (pending) {
143 		int i;
144 		for (i=0; i<NR_CPUS; i++) {
145 			int cpu;
146 #ifdef CONFIG_SMP
147 			cpu = cpu_logical_map(i);
148 #else
149 			cpu = i;
150 #endif
151 			/*
152 			 * Clear for all CPUs so an affinity switch
153 			 * doesn't find an old status
154 			 */
155 			__raw_writeq(pending,
156 				     IOADDR(A_IMR_REGISTER(cpu,
157 						R_IMR_LDT_INTERRUPT_CLR)));
158 		}
159 
160 		/*
161 		 * Generate EOI.  For Pass 1 parts, EOI is a nop.  For
162 		 * Pass 2, the LDT world may be edge-triggered, but
163 		 * this EOI shouldn't hurt.  If they are
164 		 * level-sensitive, the EOI is required.
165 		 */
166 		*(uint32_t *)(ldt_eoi_space+(irq<<16)+(7<<2)) = 0;
167 	}
168 #endif
169 	sb1250_mask_irq(sb1250_irq_owner[irq], irq);
170 }
171 
172 static struct irq_chip sb1250_irq_type = {
173 	.name = "SB1250-IMR",
174 	.irq_mask_ack = ack_sb1250_irq,
175 	.irq_unmask = enable_sb1250_irq,
176 	.irq_mask = disable_sb1250_irq,
177 #ifdef CONFIG_SMP
178 	.irq_set_affinity = sb1250_set_affinity
179 #endif
180 };
181 
init_sb1250_irqs(void)182 void __init init_sb1250_irqs(void)
183 {
184 	int i;
185 
186 	for (i = 0; i < SB1250_NR_IRQS; i++) {
187 		irq_set_chip_and_handler(i, &sb1250_irq_type,
188 					 handle_level_irq);
189 		sb1250_irq_owner[i] = 0;
190 	}
191 }
192 
193 
194 /*
195  *  arch_init_irq is called early in the boot sequence from init/main.c via
196  *  init_IRQ.  It is responsible for setting up the interrupt mapper and
197  *  installing the handler that will be responsible for dispatching interrupts
198  *  to the "right" place.
199  */
200 /*
201  * For now, map all interrupts to IP[2].  We could save
202  * some cycles by parceling out system interrupts to different
203  * IP lines, but keep it simple for bringup.  We'll also direct
204  * all interrupts to a single CPU; we should probably route
205  * PCI and LDT to one cpu and everything else to the other
206  * to balance the load a bit.
207  *
208  * On the second cpu, everything is set to IP5, which is
209  * ignored, EXCEPT the mailbox interrupt.  That one is
210  * set to IP[2] so it is handled.  This is needed so we
211  * can do cross-cpu function calls, as required by SMP
212  */
213 
214 #define IMR_IP2_VAL	K_INT_MAP_I0
215 #define IMR_IP3_VAL	K_INT_MAP_I1
216 #define IMR_IP4_VAL	K_INT_MAP_I2
217 #define IMR_IP5_VAL	K_INT_MAP_I3
218 #define IMR_IP6_VAL	K_INT_MAP_I4
219 
arch_init_irq(void)220 void __init arch_init_irq(void)
221 {
222 
223 	unsigned int i;
224 	u64 tmp;
225 	unsigned int imask = STATUSF_IP4 | STATUSF_IP3 | STATUSF_IP2 |
226 		STATUSF_IP1 | STATUSF_IP0;
227 
228 	/* Default everything to IP2 */
229 	for (i = 0; i < SB1250_NR_IRQS; i++) {	/* was I0 */
230 		__raw_writeq(IMR_IP2_VAL,
231 			     IOADDR(A_IMR_REGISTER(0,
232 						   R_IMR_INTERRUPT_MAP_BASE) +
233 				    (i << 3)));
234 		__raw_writeq(IMR_IP2_VAL,
235 			     IOADDR(A_IMR_REGISTER(1,
236 						   R_IMR_INTERRUPT_MAP_BASE) +
237 				    (i << 3)));
238 	}
239 
240 	init_sb1250_irqs();
241 
242 	/*
243 	 * Map the high 16 bits of the mailbox registers to IP[3], for
244 	 * inter-cpu messages
245 	 */
246 	/* Was I1 */
247 	__raw_writeq(IMR_IP3_VAL,
248 		     IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MAP_BASE) +
249 			    (K_INT_MBOX_0 << 3)));
250 	__raw_writeq(IMR_IP3_VAL,
251 		     IOADDR(A_IMR_REGISTER(1, R_IMR_INTERRUPT_MAP_BASE) +
252 			    (K_INT_MBOX_0 << 3)));
253 
254 	/* Clear the mailboxes.	 The firmware may leave them dirty */
255 	__raw_writeq(0xffffffffffffffffULL,
256 		     IOADDR(A_IMR_REGISTER(0, R_IMR_MAILBOX_CLR_CPU)));
257 	__raw_writeq(0xffffffffffffffffULL,
258 		     IOADDR(A_IMR_REGISTER(1, R_IMR_MAILBOX_CLR_CPU)));
259 
260 	/* Mask everything except the mailbox registers for both cpus */
261 	tmp = ~((u64) 0) ^ (((u64) 1) << K_INT_MBOX_0);
262 	__raw_writeq(tmp, IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MASK)));
263 	__raw_writeq(tmp, IOADDR(A_IMR_REGISTER(1, R_IMR_INTERRUPT_MASK)));
264 
265 	/* Enable necessary IPs, disable the rest */
266 	change_c0_status(ST0_IM, imask);
267 }
268 
269 extern void sb1250_mailbox_interrupt(void);
270 
dispatch_ip2(void)271 static inline void dispatch_ip2(void)
272 {
273 	unsigned int cpu = smp_processor_id();
274 	unsigned long long mask;
275 
276 	/*
277 	 * Default...we've hit an IP[2] interrupt, which means we've got to
278 	 * check the 1250 interrupt registers to figure out what to do.	 Need
279 	 * to detect which CPU we're on, now that smp_affinity is supported.
280 	 */
281 	mask = __raw_readq(IOADDR(A_IMR_REGISTER(cpu,
282 				  R_IMR_INTERRUPT_STATUS_BASE)));
283 	if (mask)
284 		do_IRQ(fls64(mask) - 1);
285 }
286 
plat_irq_dispatch(void)287 asmlinkage void plat_irq_dispatch(void)
288 {
289 	unsigned int cpu = smp_processor_id();
290 	unsigned int pending;
291 
292 	/*
293 	 * What a pain. We have to be really careful saving the upper 32 bits
294 	 * of any * register across function calls if we don't want them
295 	 * trashed--since were running in -o32, the calling routing never saves
296 	 * the full 64 bits of a register across a function call.  Being the
297 	 * interrupt handler, we're guaranteed that interrupts are disabled
298 	 * during this code so we don't have to worry about random interrupts
299 	 * blasting the high 32 bits.
300 	 */
301 
302 	pending = read_c0_cause() & read_c0_status() & ST0_IM;
303 
304 	if (pending & CAUSEF_IP7) /* CPU performance counter interrupt */
305 		do_IRQ(MIPS_CPU_IRQ_BASE + 7);
306 	else if (pending & CAUSEF_IP4)
307 		do_IRQ(K_INT_TIMER_0 + cpu);	/* sb1250_timer_interrupt() */
308 
309 #ifdef CONFIG_SMP
310 	else if (pending & CAUSEF_IP3)
311 		sb1250_mailbox_interrupt();
312 #endif
313 
314 	else if (pending & CAUSEF_IP2)
315 		dispatch_ip2();
316 	else
317 		spurious_interrupt();
318 }
319