1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * ip22-int.c: Routines for generic manipulation of the INT[23] ASIC
4  *	       found on INDY and Indigo2 workstations.
5  *
6  * Copyright (C) 1996 David S. Miller (davem@davemloft.net)
7  * Copyright (C) 1997, 1998 Ralf Baechle (ralf@gnu.org)
8  * Copyright (C) 1999 Andrew R. Baker (andrewb@uab.edu)
9  *		      - Indigo2 changes
10  *		      - Interrupt handling fixes
11  * Copyright (C) 2001, 2003 Ladislav Michl (ladis@linux-mips.org)
12  */
13 #include <linux/types.h>
14 #include <linux/init.h>
15 #include <linux/kernel_stat.h>
16 #include <linux/interrupt.h>
17 #include <linux/ftrace.h>
18 
19 #include <asm/irq_cpu.h>
20 #include <asm/sgi/hpc3.h>
21 #include <asm/sgi/ip22.h>
22 
23 /* So far nothing hangs here */
24 #undef USE_LIO3_IRQ
25 
26 struct sgint_regs *sgint;
27 
28 static char lc0msk_to_irqnr[256];
29 static char lc1msk_to_irqnr[256];
30 static char lc2msk_to_irqnr[256];
31 static char lc3msk_to_irqnr[256];
32 
33 extern int ip22_eisa_init(void);
34 
enable_local0_irq(struct irq_data * d)35 static void enable_local0_irq(struct irq_data *d)
36 {
37 	/* don't allow mappable interrupt to be enabled from setup_irq,
38 	 * we have our own way to do so */
39 	if (d->irq != SGI_MAP_0_IRQ)
40 		sgint->imask0 |= (1 << (d->irq - SGINT_LOCAL0));
41 }
42 
disable_local0_irq(struct irq_data * d)43 static void disable_local0_irq(struct irq_data *d)
44 {
45 	sgint->imask0 &= ~(1 << (d->irq - SGINT_LOCAL0));
46 }
47 
48 static struct irq_chip ip22_local0_irq_type = {
49 	.name		= "IP22 local 0",
50 	.irq_mask	= disable_local0_irq,
51 	.irq_unmask	= enable_local0_irq,
52 };
53 
enable_local1_irq(struct irq_data * d)54 static void enable_local1_irq(struct irq_data *d)
55 {
56 	/* don't allow mappable interrupt to be enabled from setup_irq,
57 	 * we have our own way to do so */
58 	if (d->irq != SGI_MAP_1_IRQ)
59 		sgint->imask1 |= (1 << (d->irq - SGINT_LOCAL1));
60 }
61 
disable_local1_irq(struct irq_data * d)62 static void disable_local1_irq(struct irq_data *d)
63 {
64 	sgint->imask1 &= ~(1 << (d->irq - SGINT_LOCAL1));
65 }
66 
67 static struct irq_chip ip22_local1_irq_type = {
68 	.name		= "IP22 local 1",
69 	.irq_mask	= disable_local1_irq,
70 	.irq_unmask	= enable_local1_irq,
71 };
72 
enable_local2_irq(struct irq_data * d)73 static void enable_local2_irq(struct irq_data *d)
74 {
75 	sgint->imask0 |= (1 << (SGI_MAP_0_IRQ - SGINT_LOCAL0));
76 	sgint->cmeimask0 |= (1 << (d->irq - SGINT_LOCAL2));
77 }
78 
disable_local2_irq(struct irq_data * d)79 static void disable_local2_irq(struct irq_data *d)
80 {
81 	sgint->cmeimask0 &= ~(1 << (d->irq - SGINT_LOCAL2));
82 	if (!sgint->cmeimask0)
83 		sgint->imask0 &= ~(1 << (SGI_MAP_0_IRQ - SGINT_LOCAL0));
84 }
85 
86 static struct irq_chip ip22_local2_irq_type = {
87 	.name		= "IP22 local 2",
88 	.irq_mask	= disable_local2_irq,
89 	.irq_unmask	= enable_local2_irq,
90 };
91 
enable_local3_irq(struct irq_data * d)92 static void enable_local3_irq(struct irq_data *d)
93 {
94 	sgint->imask1 |= (1 << (SGI_MAP_1_IRQ - SGINT_LOCAL1));
95 	sgint->cmeimask1 |= (1 << (d->irq - SGINT_LOCAL3));
96 }
97 
disable_local3_irq(struct irq_data * d)98 static void disable_local3_irq(struct irq_data *d)
99 {
100 	sgint->cmeimask1 &= ~(1 << (d->irq - SGINT_LOCAL3));
101 	if (!sgint->cmeimask1)
102 		sgint->imask1 &= ~(1 << (SGI_MAP_1_IRQ - SGINT_LOCAL1));
103 }
104 
105 static struct irq_chip ip22_local3_irq_type = {
106 	.name		= "IP22 local 3",
107 	.irq_mask	= disable_local3_irq,
108 	.irq_unmask	= enable_local3_irq,
109 };
110 
indy_local0_irqdispatch(void)111 static void indy_local0_irqdispatch(void)
112 {
113 	u8 mask = sgint->istat0 & sgint->imask0;
114 	u8 mask2;
115 	int irq;
116 
117 	if (mask & SGINT_ISTAT0_LIO2) {
118 		mask2 = sgint->vmeistat & sgint->cmeimask0;
119 		irq = lc2msk_to_irqnr[mask2];
120 	} else
121 		irq = lc0msk_to_irqnr[mask];
122 
123 	/*
124 	 * workaround for INT2 bug; if irq == 0, INT2 has seen a fifo full
125 	 * irq, but failed to latch it into status register
126 	 */
127 	if (irq)
128 		do_IRQ(irq);
129 	else
130 		do_IRQ(SGINT_LOCAL0 + 0);
131 }
132 
indy_local1_irqdispatch(void)133 static void indy_local1_irqdispatch(void)
134 {
135 	u8 mask = sgint->istat1 & sgint->imask1;
136 	u8 mask2;
137 	int irq;
138 
139 	if (mask & SGINT_ISTAT1_LIO3) {
140 		mask2 = sgint->vmeistat & sgint->cmeimask1;
141 		irq = lc3msk_to_irqnr[mask2];
142 	} else
143 		irq = lc1msk_to_irqnr[mask];
144 
145 	/* if irq == 0, then the interrupt has already been cleared */
146 	if (irq)
147 		do_IRQ(irq);
148 }
149 
150 extern void ip22_be_interrupt(int irq);
151 
indy_buserror_irq(void)152 static void __irq_entry indy_buserror_irq(void)
153 {
154 	int irq = SGI_BUSERR_IRQ;
155 
156 	irq_enter();
157 	kstat_incr_irq_this_cpu(irq);
158 	ip22_be_interrupt(irq);
159 	irq_exit();
160 }
161 
162 #ifdef USE_LIO3_IRQ
163 #define SGI_INTERRUPTS	SGINT_END
164 #else
165 #define SGI_INTERRUPTS	SGINT_LOCAL3
166 #endif
167 
168 /*
169  * IRQs on the INDY look basically (barring software IRQs which we don't use
170  * at all) like:
171  *
172  *	MIPS IRQ	Source
173  *	--------	------
174  *	       0	Software (ignored)
175  *	       1	Software (ignored)
176  *	       2	Local IRQ level zero
177  *	       3	Local IRQ level one
178  *	       4	8254 Timer zero
179  *	       5	8254 Timer one
180  *	       6	Bus Error
181  *	       7	R4k timer (what we use)
182  *
183  * We handle the IRQ according to _our_ priority which is:
184  *
185  * Highest ----	    R4k Timer
186  *		    Local IRQ zero
187  *		    Local IRQ one
188  *		    Bus Error
189  *		    8254 Timer zero
190  * Lowest  ----	    8254 Timer one
191  *
192  * then we just return, if multiple IRQs are pending then we will just take
193  * another exception, big deal.
194  */
195 
plat_irq_dispatch(void)196 asmlinkage void plat_irq_dispatch(void)
197 {
198 	unsigned int pending = read_c0_status() & read_c0_cause();
199 
200 	/*
201 	 * First we check for r4k counter/timer IRQ.
202 	 */
203 	if (pending & CAUSEF_IP7)
204 		do_IRQ(SGI_TIMER_IRQ);
205 	else if (pending & CAUSEF_IP2)
206 		indy_local0_irqdispatch();
207 	else if (pending & CAUSEF_IP3)
208 		indy_local1_irqdispatch();
209 	else if (pending & CAUSEF_IP6)
210 		indy_buserror_irq();
211 	else if (pending & (CAUSEF_IP4 | CAUSEF_IP5))
212 		indy_8254timer_irq();
213 }
214 
arch_init_irq(void)215 void __init arch_init_irq(void)
216 {
217 	int i;
218 
219 	/* Init local mask --> irq tables. */
220 	for (i = 0; i < 256; i++) {
221 		if (i & 0x80) {
222 			lc0msk_to_irqnr[i] = SGINT_LOCAL0 + 7;
223 			lc1msk_to_irqnr[i] = SGINT_LOCAL1 + 7;
224 			lc2msk_to_irqnr[i] = SGINT_LOCAL2 + 7;
225 			lc3msk_to_irqnr[i] = SGINT_LOCAL3 + 7;
226 		} else if (i & 0x40) {
227 			lc0msk_to_irqnr[i] = SGINT_LOCAL0 + 6;
228 			lc1msk_to_irqnr[i] = SGINT_LOCAL1 + 6;
229 			lc2msk_to_irqnr[i] = SGINT_LOCAL2 + 6;
230 			lc3msk_to_irqnr[i] = SGINT_LOCAL3 + 6;
231 		} else if (i & 0x20) {
232 			lc0msk_to_irqnr[i] = SGINT_LOCAL0 + 5;
233 			lc1msk_to_irqnr[i] = SGINT_LOCAL1 + 5;
234 			lc2msk_to_irqnr[i] = SGINT_LOCAL2 + 5;
235 			lc3msk_to_irqnr[i] = SGINT_LOCAL3 + 5;
236 		} else if (i & 0x10) {
237 			lc0msk_to_irqnr[i] = SGINT_LOCAL0 + 4;
238 			lc1msk_to_irqnr[i] = SGINT_LOCAL1 + 4;
239 			lc2msk_to_irqnr[i] = SGINT_LOCAL2 + 4;
240 			lc3msk_to_irqnr[i] = SGINT_LOCAL3 + 4;
241 		} else if (i & 0x08) {
242 			lc0msk_to_irqnr[i] = SGINT_LOCAL0 + 3;
243 			lc1msk_to_irqnr[i] = SGINT_LOCAL1 + 3;
244 			lc2msk_to_irqnr[i] = SGINT_LOCAL2 + 3;
245 			lc3msk_to_irqnr[i] = SGINT_LOCAL3 + 3;
246 		} else if (i & 0x04) {
247 			lc0msk_to_irqnr[i] = SGINT_LOCAL0 + 2;
248 			lc1msk_to_irqnr[i] = SGINT_LOCAL1 + 2;
249 			lc2msk_to_irqnr[i] = SGINT_LOCAL2 + 2;
250 			lc3msk_to_irqnr[i] = SGINT_LOCAL3 + 2;
251 		} else if (i & 0x02) {
252 			lc0msk_to_irqnr[i] = SGINT_LOCAL0 + 1;
253 			lc1msk_to_irqnr[i] = SGINT_LOCAL1 + 1;
254 			lc2msk_to_irqnr[i] = SGINT_LOCAL2 + 1;
255 			lc3msk_to_irqnr[i] = SGINT_LOCAL3 + 1;
256 		} else if (i & 0x01) {
257 			lc0msk_to_irqnr[i] = SGINT_LOCAL0 + 0;
258 			lc1msk_to_irqnr[i] = SGINT_LOCAL1 + 0;
259 			lc2msk_to_irqnr[i] = SGINT_LOCAL2 + 0;
260 			lc3msk_to_irqnr[i] = SGINT_LOCAL3 + 0;
261 		} else {
262 			lc0msk_to_irqnr[i] = 0;
263 			lc1msk_to_irqnr[i] = 0;
264 			lc2msk_to_irqnr[i] = 0;
265 			lc3msk_to_irqnr[i] = 0;
266 		}
267 	}
268 
269 	/* Mask out all interrupts. */
270 	sgint->imask0 = 0;
271 	sgint->imask1 = 0;
272 	sgint->cmeimask0 = 0;
273 	sgint->cmeimask1 = 0;
274 
275 	/* init CPU irqs */
276 	mips_cpu_irq_init();
277 
278 	for (i = SGINT_LOCAL0; i < SGI_INTERRUPTS; i++) {
279 		struct irq_chip *handler;
280 
281 		if (i < SGINT_LOCAL1)
282 			handler		= &ip22_local0_irq_type;
283 		else if (i < SGINT_LOCAL2)
284 			handler		= &ip22_local1_irq_type;
285 		else if (i < SGINT_LOCAL3)
286 			handler		= &ip22_local2_irq_type;
287 		else
288 			handler		= &ip22_local3_irq_type;
289 
290 		irq_set_chip_and_handler(i, handler, handle_level_irq);
291 	}
292 
293 	/* vector handler. this register the IRQ as non-sharable */
294 	if (request_irq(SGI_LOCAL_0_IRQ, no_action, IRQF_NO_THREAD,
295 			"local0 cascade", NULL))
296 		pr_err("Failed to register local0 cascade interrupt\n");
297 	if (request_irq(SGI_LOCAL_1_IRQ, no_action, IRQF_NO_THREAD,
298 			"local1 cascade", NULL))
299 		pr_err("Failed to register local1 cascade interrupt\n");
300 	if (request_irq(SGI_BUSERR_IRQ, no_action, IRQF_NO_THREAD,
301 			"Bus Error", NULL))
302 		pr_err("Failed to register Bus Error interrupt\n");
303 
304 	/* cascade in cascade. i love Indy ;-) */
305 	if (request_irq(SGI_MAP_0_IRQ, no_action, IRQF_NO_THREAD,
306 			"mapable0 cascade", NULL))
307 		pr_err("Failed to register mapable0 cascade interrupt\n");
308 #ifdef USE_LIO3_IRQ
309 	if (request_irq(SGI_MAP_1_IRQ, no_action, IRQF_NO_THREAD,
310 			"mapable1 cascade", NULL))
311 		pr_err("Failed to register mapable1 cascade interrupt\n");
312 #endif
313 
314 #ifdef CONFIG_EISA
315 	if (ip22_is_fullhouse())	/* Only Indigo-2 has EISA stuff */
316 		ip22_eisa_init();
317 #endif
318 }
319