1 /*
2 * arch/m68k/atari/ataints.c -- Atari Linux interrupt handling code
3 *
4 * 5/2/94 Roman Hodek:
5 * Added support for TT interrupts; setup for TT SCU (may someone has
6 * twiddled there and we won't get the right interrupts :-()
7 *
8 * Major change: The device-independent code in m68k/ints.c didn't know
9 * about non-autovec ints yet. It hardcoded the number of possible ints to
10 * 7 (IRQ1...IRQ7). But the Atari has lots of non-autovec ints! I made the
11 * number of possible ints a constant defined in interrupt.h, which is
12 * 47 for the Atari. So we can call request_irq() for all Atari interrupts
13 * just the normal way. Additionally, all vectors >= 48 are initialized to
14 * call trap() instead of inthandler(). This must be changed here, too.
15 *
16 * 1995-07-16 Lars Brinkhoff <f93labr@dd.chalmers.se>:
17 * Corrected a bug in atari_add_isr() which rejected all SCC
18 * interrupt sources if there were no TT MFP!
19 *
20 * 12/13/95: New interface functions atari_level_triggered_int() and
21 * atari_register_vme_int() as support for level triggered VME interrupts.
22 *
23 * 02/12/96: (Roman)
24 * Total rewrite of Atari interrupt handling, for new scheme see comments
25 * below.
26 *
27 * 1996-09-03 lars brinkhoff <f93labr@dd.chalmers.se>:
28 * Added new function atari_unregister_vme_int(), and
29 * modified atari_register_vme_int() as well as IS_VALID_INTNO()
30 * to work with it.
31 *
32 * This file is subject to the terms and conditions of the GNU General Public
33 * License. See the file COPYING in the main directory of this archive
34 * for more details.
35 *
36 */
37
38 #include <linux/types.h>
39 #include <linux/kernel.h>
40 #include <linux/kernel_stat.h>
41 #include <linux/init.h>
42 #include <linux/seq_file.h>
43 #include <linux/module.h>
44
45 #include <asm/system.h>
46 #include <asm/traps.h>
47
48 #include <asm/atarihw.h>
49 #include <asm/atariints.h>
50 #include <asm/atari_stdma.h>
51 #include <asm/irq.h>
52 #include <asm/entry.h>
53
54
55 /*
56 * Atari interrupt handling scheme:
57 * --------------------------------
58 *
59 * All interrupt source have an internal number (defined in
60 * <asm/atariints.h>): Autovector interrupts are 1..7, then follow ST-MFP,
61 * TT-MFP, SCC, and finally VME interrupts. Vector numbers for the latter can
62 * be allocated by atari_register_vme_int().
63 *
64 * Each interrupt can be of three types:
65 *
66 * - SLOW: The handler runs with all interrupts enabled, except the one it
67 * was called by (to avoid reentering). This should be the usual method.
68 * But it is currently possible only for MFP ints, since only the MFP
69 * offers an easy way to mask interrupts.
70 *
71 * - FAST: The handler runs with all interrupts disabled. This should be used
72 * only for really fast handlers, that just do actions immediately
73 * necessary, and let the rest do a bottom half or task queue.
74 *
75 * - PRIORITIZED: The handler can be interrupted by higher-level ints
76 * (greater IPL, no MFP priorities!). This is the method of choice for ints
77 * which should be slow, but are not from a MFP.
78 *
79 * The feature of more than one handler for one int source is still there, but
80 * only applicable if all handers are of the same type. To not slow down
81 * processing of ints with only one handler by the chaining feature, the list
82 * calling function atari_call_irq_list() is only plugged in at the time the
83 * second handler is registered.
84 *
85 * Implementation notes: For fast-as-possible int handling, there are separate
86 * entry points for each type (slow/fast/prio). The assembler handler calls
87 * the irq directly in the usual case, no C wrapper is involved. In case of
88 * multiple handlers, atari_call_irq_list() is registered as handler and calls
89 * in turn the real irq's. To ease access from assembler level to the irq
90 * function pointer and accompanying data, these two are stored in a separate
91 * array, irq_handler[]. The rest of data (type, name) are put into a second
92 * array, irq_param, that is accessed from C only. For each slow interrupt (32
93 * in all) there are separate handler functions, which makes it possible to
94 * hard-code the MFP register address and value, are necessary to mask the
95 * int. If there'd be only one generic function, lots of calculations would be
96 * needed to determine MFP register and int mask from the vector number :-(
97 *
98 * Furthermore, slow ints may not lower the IPL below its previous value
99 * (before the int happened). This is needed so that an int of class PRIO, on
100 * that this int may be stacked, cannot be reentered. This feature is
101 * implemented as follows: If the stack frame format is 1 (throwaway), the int
102 * is not stacked, and the IPL is anded with 0xfbff, resulting in a new level
103 * 2, which still blocks the HSYNC, but no interrupts of interest. If the
104 * frame format is 0, the int is nested, and the old IPL value can be found in
105 * the sr copy in the frame.
106 */
107
108 #if 0
109
110 #define NUM_INT_SOURCES (8 + NUM_ATARI_SOURCES)
111
112 typedef void (*asm_irq_handler)(void);
113
114 struct irqhandler {
115 irqreturn_t (*handler)(int, void *, struct pt_regs *);
116 void *dev_id;
117 };
118
119 struct irqparam {
120 unsigned long flags;
121 const char *devname;
122 };
123
124 /*
125 * Array with irq's and their parameter data. This array is accessed from low
126 * level assembler code, so an element size of 8 allows usage of index scaling
127 * addressing mode.
128 */
129 static struct irqhandler irq_handler[NUM_INT_SOURCES];
130
131 /*
132 * This array hold the rest of parameters of int handlers: type
133 * (slow,fast,prio) and the name of the handler. These values are only
134 * accessed from C
135 */
136 static struct irqparam irq_param[NUM_INT_SOURCES];
137
138 /* check for valid int number (complex, sigh...) */
139 #define IS_VALID_INTNO(n) \
140 ((n) > 0 && \
141 /* autovec and ST-MFP ok anyway */ \
142 (((n) < TTMFP_SOURCE_BASE) || \
143 /* TT-MFP ok if present */ \
144 ((n) >= TTMFP_SOURCE_BASE && (n) < SCC_SOURCE_BASE && \
145 ATARIHW_PRESENT(TT_MFP)) || \
146 /* SCC ok if present and number even */ \
147 ((n) >= SCC_SOURCE_BASE && (n) < VME_SOURCE_BASE && \
148 !((n) & 1) && ATARIHW_PRESENT(SCC)) || \
149 /* greater numbers ok if they are registered VME vectors */ \
150 ((n) >= VME_SOURCE_BASE && (n) < VME_SOURCE_BASE + VME_MAX_SOURCES && \
151 free_vme_vec_bitmap & (1 << ((n) - VME_SOURCE_BASE)))))
152
153
154 /*
155 * Here start the assembler entry points for interrupts
156 */
157
158 #define IRQ_NAME(nr) atari_slow_irq_##nr##_handler(void)
159
160 #define BUILD_SLOW_IRQ(n) \
161 asmlinkage void IRQ_NAME(n); \
162 /* Dummy function to allow asm with operands. */ \
163 void atari_slow_irq_##n##_dummy (void) { \
164 __asm__ (__ALIGN_STR "\n" \
165 "atari_slow_irq_" #n "_handler:\t" \
166 " addl %6,%5\n" /* preempt_count() += HARDIRQ_OFFSET */ \
167 SAVE_ALL_INT "\n" \
168 GET_CURRENT(%%d0) "\n" \
169 " andb #~(1<<(%c3&7)),%a4:w\n" /* mask this interrupt */ \
170 /* get old IPL from stack frame */ \
171 " bfextu %%sp@(%c2){#5,#3},%%d0\n" \
172 " movew %%sr,%%d1\n" \
173 " bfins %%d0,%%d1{#21,#3}\n" \
174 " movew %%d1,%%sr\n" /* set IPL = previous value */ \
175 " addql #1,%a0\n" \
176 " lea %a1,%%a0\n" \
177 " pea %%sp@\n" /* push addr of frame */ \
178 " movel %%a0@(4),%%sp@-\n" /* push handler data */ \
179 " pea (%c3+8)\n" /* push int number */ \
180 " movel %%a0@,%%a0\n" \
181 " jbsr %%a0@\n" /* call the handler */ \
182 " addql #8,%%sp\n" \
183 " addql #4,%%sp\n" \
184 " orw #0x0600,%%sr\n" \
185 " andw #0xfeff,%%sr\n" /* set IPL = 6 again */ \
186 " orb #(1<<(%c3&7)),%a4:w\n" /* now unmask the int again */ \
187 " jbra ret_from_interrupt\n" \
188 : : "i" (&kstat_cpu(0).irqs[n+8]), "i" (&irq_handler[n+8]), \
189 "n" (PT_OFF_SR), "n" (n), \
190 "i" (n & 8 ? (n & 16 ? &tt_mfp.int_mk_a : &st_mfp.int_mk_a) \
191 : (n & 16 ? &tt_mfp.int_mk_b : &st_mfp.int_mk_b)), \
192 "m" (preempt_count()), "di" (HARDIRQ_OFFSET) \
193 ); \
194 for (;;); /* fake noreturn */ \
195 }
196
197 BUILD_SLOW_IRQ(0);
198 BUILD_SLOW_IRQ(1);
199 BUILD_SLOW_IRQ(2);
200 BUILD_SLOW_IRQ(3);
201 BUILD_SLOW_IRQ(4);
202 BUILD_SLOW_IRQ(5);
203 BUILD_SLOW_IRQ(6);
204 BUILD_SLOW_IRQ(7);
205 BUILD_SLOW_IRQ(8);
206 BUILD_SLOW_IRQ(9);
207 BUILD_SLOW_IRQ(10);
208 BUILD_SLOW_IRQ(11);
209 BUILD_SLOW_IRQ(12);
210 BUILD_SLOW_IRQ(13);
211 BUILD_SLOW_IRQ(14);
212 BUILD_SLOW_IRQ(15);
213 BUILD_SLOW_IRQ(16);
214 BUILD_SLOW_IRQ(17);
215 BUILD_SLOW_IRQ(18);
216 BUILD_SLOW_IRQ(19);
217 BUILD_SLOW_IRQ(20);
218 BUILD_SLOW_IRQ(21);
219 BUILD_SLOW_IRQ(22);
220 BUILD_SLOW_IRQ(23);
221 BUILD_SLOW_IRQ(24);
222 BUILD_SLOW_IRQ(25);
223 BUILD_SLOW_IRQ(26);
224 BUILD_SLOW_IRQ(27);
225 BUILD_SLOW_IRQ(28);
226 BUILD_SLOW_IRQ(29);
227 BUILD_SLOW_IRQ(30);
228 BUILD_SLOW_IRQ(31);
229
230 asm_irq_handler slow_handlers[32] = {
231 [0] = atari_slow_irq_0_handler,
232 [1] = atari_slow_irq_1_handler,
233 [2] = atari_slow_irq_2_handler,
234 [3] = atari_slow_irq_3_handler,
235 [4] = atari_slow_irq_4_handler,
236 [5] = atari_slow_irq_5_handler,
237 [6] = atari_slow_irq_6_handler,
238 [7] = atari_slow_irq_7_handler,
239 [8] = atari_slow_irq_8_handler,
240 [9] = atari_slow_irq_9_handler,
241 [10] = atari_slow_irq_10_handler,
242 [11] = atari_slow_irq_11_handler,
243 [12] = atari_slow_irq_12_handler,
244 [13] = atari_slow_irq_13_handler,
245 [14] = atari_slow_irq_14_handler,
246 [15] = atari_slow_irq_15_handler,
247 [16] = atari_slow_irq_16_handler,
248 [17] = atari_slow_irq_17_handler,
249 [18] = atari_slow_irq_18_handler,
250 [19] = atari_slow_irq_19_handler,
251 [20] = atari_slow_irq_20_handler,
252 [21] = atari_slow_irq_21_handler,
253 [22] = atari_slow_irq_22_handler,
254 [23] = atari_slow_irq_23_handler,
255 [24] = atari_slow_irq_24_handler,
256 [25] = atari_slow_irq_25_handler,
257 [26] = atari_slow_irq_26_handler,
258 [27] = atari_slow_irq_27_handler,
259 [28] = atari_slow_irq_28_handler,
260 [29] = atari_slow_irq_29_handler,
261 [30] = atari_slow_irq_30_handler,
262 [31] = atari_slow_irq_31_handler
263 };
264
265 asmlinkage void atari_fast_irq_handler( void );
266 asmlinkage void atari_prio_irq_handler( void );
267
268 /* Dummy function to allow asm with operands. */
269 void atari_fast_prio_irq_dummy (void) {
270 __asm__ (__ALIGN_STR "\n"
271 "atari_fast_irq_handler:\n\t"
272 "orw #0x700,%%sr\n" /* disable all interrupts */
273 "atari_prio_irq_handler:\n\t"
274 "addl %3,%2\n\t" /* preempt_count() += HARDIRQ_OFFSET */
275 SAVE_ALL_INT "\n\t"
276 GET_CURRENT(%%d0) "\n\t"
277 /* get vector number from stack frame and convert to source */
278 "bfextu %%sp@(%c1){#4,#10},%%d0\n\t"
279 "subw #(0x40-8),%%d0\n\t"
280 "jpl 1f\n\t"
281 "addw #(0x40-8-0x18),%%d0\n"
282 "1:\tlea %a0,%%a0\n\t"
283 "addql #1,%%a0@(%%d0:l:4)\n\t"
284 "lea irq_handler,%%a0\n\t"
285 "lea %%a0@(%%d0:l:8),%%a0\n\t"
286 "pea %%sp@\n\t" /* push frame address */
287 "movel %%a0@(4),%%sp@-\n\t" /* push handler data */
288 "movel %%d0,%%sp@-\n\t" /* push int number */
289 "movel %%a0@,%%a0\n\t"
290 "jsr %%a0@\n\t" /* and call the handler */
291 "addql #8,%%sp\n\t"
292 "addql #4,%%sp\n\t"
293 "jbra ret_from_interrupt"
294 : : "i" (&kstat_cpu(0).irqs), "n" (PT_OFF_FORMATVEC),
295 "m" (preempt_count()), "di" (HARDIRQ_OFFSET)
296 );
297 for (;;);
298 }
299 #endif
300
301 /*
302 * Bitmap for free interrupt vector numbers
303 * (new vectors starting from 0x70 can be allocated by
304 * atari_register_vme_int())
305 */
306 static int free_vme_vec_bitmap;
307
308 /* GK:
309 * HBL IRQ handler for Falcon. Nobody needs it :-)
310 * ++andreas: raise ipl to disable further HBLANK interrupts.
311 */
312 asmlinkage void falcon_hblhandler(void);
313 asm(".text\n"
314 __ALIGN_STR "\n\t"
315 "falcon_hblhandler:\n\t"
316 "orw #0x200,%sp@\n\t" /* set saved ipl to 2 */
317 "rte");
318
319 extern void atari_microwire_cmd(int cmd);
320
321 extern int atari_SCC_reset_done;
322
atari_startup_irq(unsigned int irq)323 static int atari_startup_irq(unsigned int irq)
324 {
325 m68k_irq_startup(irq);
326 atari_turnon_irq(irq);
327 atari_enable_irq(irq);
328 return 0;
329 }
330
atari_shutdown_irq(unsigned int irq)331 static void atari_shutdown_irq(unsigned int irq)
332 {
333 atari_disable_irq(irq);
334 atari_turnoff_irq(irq);
335 m68k_irq_shutdown(irq);
336
337 if (irq == IRQ_AUTO_4)
338 vectors[VEC_INT4] = falcon_hblhandler;
339 }
340
341 static struct irq_controller atari_irq_controller = {
342 .name = "atari",
343 .lock = __SPIN_LOCK_UNLOCKED(atari_irq_controller.lock),
344 .startup = atari_startup_irq,
345 .shutdown = atari_shutdown_irq,
346 .enable = atari_enable_irq,
347 .disable = atari_disable_irq,
348 };
349
350 /*
351 * void atari_init_IRQ (void)
352 *
353 * Parameters: None
354 *
355 * Returns: Nothing
356 *
357 * This function should be called during kernel startup to initialize
358 * the atari IRQ handling routines.
359 */
360
atari_init_IRQ(void)361 void __init atari_init_IRQ(void)
362 {
363 m68k_setup_user_interrupt(VEC_USER, NUM_ATARI_SOURCES - IRQ_USER, NULL);
364 m68k_setup_irq_controller(&atari_irq_controller, 1, NUM_ATARI_SOURCES - 1);
365
366 /* Initialize the MFP(s) */
367
368 #ifdef ATARI_USE_SOFTWARE_EOI
369 st_mfp.vec_adr = 0x48; /* Software EOI-Mode */
370 #else
371 st_mfp.vec_adr = 0x40; /* Automatic EOI-Mode */
372 #endif
373 st_mfp.int_en_a = 0x00; /* turn off MFP-Ints */
374 st_mfp.int_en_b = 0x00;
375 st_mfp.int_mk_a = 0xff; /* no Masking */
376 st_mfp.int_mk_b = 0xff;
377
378 if (ATARIHW_PRESENT(TT_MFP)) {
379 #ifdef ATARI_USE_SOFTWARE_EOI
380 tt_mfp.vec_adr = 0x58; /* Software EOI-Mode */
381 #else
382 tt_mfp.vec_adr = 0x50; /* Automatic EOI-Mode */
383 #endif
384 tt_mfp.int_en_a = 0x00; /* turn off MFP-Ints */
385 tt_mfp.int_en_b = 0x00;
386 tt_mfp.int_mk_a = 0xff; /* no Masking */
387 tt_mfp.int_mk_b = 0xff;
388 }
389
390 if (ATARIHW_PRESENT(SCC) && !atari_SCC_reset_done) {
391 atari_scc.cha_a_ctrl = 9;
392 MFPDELAY();
393 atari_scc.cha_a_ctrl = (char) 0xc0; /* hardware reset */
394 }
395
396 if (ATARIHW_PRESENT(SCU)) {
397 /* init the SCU if present */
398 tt_scu.sys_mask = 0x10; /* enable VBL (for the cursor) and
399 * disable HSYNC interrupts (who
400 * needs them?) MFP and SCC are
401 * enabled in VME mask
402 */
403 tt_scu.vme_mask = 0x60; /* enable MFP and SCC ints */
404 } else {
405 /* If no SCU and no Hades, the HSYNC interrupt needs to be
406 * disabled this way. (Else _inthandler in kernel/sys_call.S
407 * gets overruns)
408 */
409
410 vectors[VEC_INT2] = falcon_hblhandler;
411 vectors[VEC_INT4] = falcon_hblhandler;
412 }
413
414 if (ATARIHW_PRESENT(PCM_8BIT) && ATARIHW_PRESENT(MICROWIRE)) {
415 /* Initialize the LM1992 Sound Controller to enable
416 the PSG sound. This is misplaced here, it should
417 be in an atasound_init(), that doesn't exist yet. */
418 atari_microwire_cmd(MW_LM1992_PSG_HIGH);
419 }
420
421 stdma_init();
422
423 /* Initialize the PSG: all sounds off, both ports output */
424 sound_ym.rd_data_reg_sel = 7;
425 sound_ym.wd_data = 0xff;
426 }
427
428
429 /*
430 * atari_register_vme_int() returns the number of a free interrupt vector for
431 * hardware with a programmable int vector (probably a VME board).
432 */
433
atari_register_vme_int(void)434 unsigned long atari_register_vme_int(void)
435 {
436 int i;
437
438 for (i = 0; i < 32; i++)
439 if ((free_vme_vec_bitmap & (1 << i)) == 0)
440 break;
441
442 if (i == 16)
443 return 0;
444
445 free_vme_vec_bitmap |= 1 << i;
446 return VME_SOURCE_BASE + i;
447 }
448 EXPORT_SYMBOL(atari_register_vme_int);
449
450
atari_unregister_vme_int(unsigned long irq)451 void atari_unregister_vme_int(unsigned long irq)
452 {
453 if (irq >= VME_SOURCE_BASE && irq < VME_SOURCE_BASE + VME_MAX_SOURCES) {
454 irq -= VME_SOURCE_BASE;
455 free_vme_vec_bitmap &= ~(1 << irq);
456 }
457 }
458 EXPORT_SYMBOL(atari_unregister_vme_int);
459
460
461