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 
65 /*
66  * Bitmap for free interrupt vector numbers
67  * (new vectors starting from 0x70 can be allocated by
68  * atari_register_vme_int())
69  */
70 static int free_vme_vec_bitmap;
71 
72 /* GK:
73  * HBL IRQ handler for Falcon. Nobody needs it :-)
74  * ++andreas: raise ipl to disable further HBLANK interrupts.
75  */
76 asmlinkage void falcon_hblhandler(void);
77 asm(".text\n"
78 __ALIGN_STR "\n\t"
79 "falcon_hblhandler:\n\t"
80 	"orw	#0x200,%sp@\n\t"	/* set saved ipl to 2 */
81 	"rte");
82 
83 extern void atari_microwire_cmd(int cmd);
84 
atari_irq_startup(struct irq_data * data)85 static unsigned int atari_irq_startup(struct irq_data *data)
86 {
87 	unsigned int irq = data->irq;
88 
89 	m68k_irq_startup(data);
90 	atari_turnon_irq(irq);
91 	atari_enable_irq(irq);
92 	return 0;
93 }
94 
atari_irq_shutdown(struct irq_data * data)95 static void atari_irq_shutdown(struct irq_data *data)
96 {
97 	unsigned int irq = data->irq;
98 
99 	atari_disable_irq(irq);
100 	atari_turnoff_irq(irq);
101 	m68k_irq_shutdown(data);
102 
103 	if (irq == IRQ_AUTO_4)
104 	    vectors[VEC_INT4] = falcon_hblhandler;
105 }
106 
atari_irq_enable(struct irq_data * data)107 static void atari_irq_enable(struct irq_data *data)
108 {
109 	atari_enable_irq(data->irq);
110 }
111 
atari_irq_disable(struct irq_data * data)112 static void atari_irq_disable(struct irq_data *data)
113 {
114 	atari_disable_irq(data->irq);
115 }
116 
117 static struct irq_chip atari_irq_chip = {
118 	.name		= "atari",
119 	.irq_startup	= atari_irq_startup,
120 	.irq_shutdown	= atari_irq_shutdown,
121 	.irq_enable	= atari_irq_enable,
122 	.irq_disable	= atari_irq_disable,
123 };
124 
125 /*
126  * void atari_init_IRQ (void)
127  *
128  * Parameters:	None
129  *
130  * Returns:	Nothing
131  *
132  * This function should be called during kernel startup to initialize
133  * the atari IRQ handling routines.
134  */
135 
atari_init_IRQ(void)136 void __init atari_init_IRQ(void)
137 {
138 	m68k_setup_user_interrupt(VEC_USER, NUM_ATARI_SOURCES - IRQ_USER);
139 	m68k_setup_irq_controller(&atari_irq_chip, handle_simple_irq, 1,
140 				  NUM_ATARI_SOURCES - 1);
141 
142 	/* Initialize the MFP(s) */
143 
144 #ifdef ATARI_USE_SOFTWARE_EOI
145 	st_mfp.vec_adr  = 0x48;	/* Software EOI-Mode */
146 #else
147 	st_mfp.vec_adr  = 0x40;	/* Automatic EOI-Mode */
148 #endif
149 	st_mfp.int_en_a = 0x00;	/* turn off MFP-Ints */
150 	st_mfp.int_en_b = 0x00;
151 	st_mfp.int_mk_a = 0xff;	/* no Masking */
152 	st_mfp.int_mk_b = 0xff;
153 
154 	if (ATARIHW_PRESENT(TT_MFP)) {
155 #ifdef ATARI_USE_SOFTWARE_EOI
156 		tt_mfp.vec_adr  = 0x58;		/* Software EOI-Mode */
157 #else
158 		tt_mfp.vec_adr  = 0x50;		/* Automatic EOI-Mode */
159 #endif
160 		tt_mfp.int_en_a = 0x00;		/* turn off MFP-Ints */
161 		tt_mfp.int_en_b = 0x00;
162 		tt_mfp.int_mk_a = 0xff;		/* no Masking */
163 		tt_mfp.int_mk_b = 0xff;
164 	}
165 
166 	if (ATARIHW_PRESENT(SCC) && !atari_SCC_reset_done) {
167 		atari_scc.cha_a_ctrl = 9;
168 		MFPDELAY();
169 		atari_scc.cha_a_ctrl = (char) 0xc0; /* hardware reset */
170 	}
171 
172 	if (ATARIHW_PRESENT(SCU)) {
173 		/* init the SCU if present */
174 		tt_scu.sys_mask = 0x10;		/* enable VBL (for the cursor) and
175 									 * disable HSYNC interrupts (who
176 									 * needs them?)  MFP and SCC are
177 									 * enabled in VME mask
178 									 */
179 		tt_scu.vme_mask = 0x60;		/* enable MFP and SCC ints */
180 	} else {
181 		/* If no SCU and no Hades, the HSYNC interrupt needs to be
182 		 * disabled this way. (Else _inthandler in kernel/sys_call.S
183 		 * gets overruns)
184 		 */
185 
186 		vectors[VEC_INT2] = falcon_hblhandler;
187 		vectors[VEC_INT4] = falcon_hblhandler;
188 	}
189 
190 	if (ATARIHW_PRESENT(PCM_8BIT) && ATARIHW_PRESENT(MICROWIRE)) {
191 		/* Initialize the LM1992 Sound Controller to enable
192 		   the PSG sound.  This is misplaced here, it should
193 		   be in an atasound_init(), that doesn't exist yet. */
194 		atari_microwire_cmd(MW_LM1992_PSG_HIGH);
195 	}
196 
197 	stdma_init();
198 
199 	/* Initialize the PSG: all sounds off, both ports output */
200 	sound_ym.rd_data_reg_sel = 7;
201 	sound_ym.wd_data = 0xff;
202 }
203 
204 
205 /*
206  * atari_register_vme_int() returns the number of a free interrupt vector for
207  * hardware with a programmable int vector (probably a VME board).
208  */
209 
atari_register_vme_int(void)210 unsigned long atari_register_vme_int(void)
211 {
212 	int i;
213 
214 	for (i = 0; i < 32; i++)
215 		if ((free_vme_vec_bitmap & (1 << i)) == 0)
216 			break;
217 
218 	if (i == 16)
219 		return 0;
220 
221 	free_vme_vec_bitmap |= 1 << i;
222 	return VME_SOURCE_BASE + i;
223 }
224 EXPORT_SYMBOL(atari_register_vme_int);
225 
226 
atari_unregister_vme_int(unsigned long irq)227 void atari_unregister_vme_int(unsigned long irq)
228 {
229 	if (irq >= VME_SOURCE_BASE && irq < VME_SOURCE_BASE + VME_MAX_SOURCES) {
230 		irq -= VME_SOURCE_BASE;
231 		free_vme_vec_bitmap &= ~(1 << irq);
232 	}
233 }
234 EXPORT_SYMBOL(atari_unregister_vme_int);
235 
236 
237