xref: /openbmc/qemu/hw/m68k/q800-glue.c (revision bad5cfcd)
1 /*
2  * QEMU q800 logic GLUE (General Logic Unit)
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a copy
5  * of this software and associated documentation files (the "Software"), to deal
6  * in the Software without restriction, including without limitation the rights
7  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8  * copies of the Software, and to permit persons to whom the Software is
9  * furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
17  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
20  * THE SOFTWARE.
21  */
22 
23 #include "qemu/osdep.h"
24 #include "cpu.h"
25 #include "hw/m68k/q800-glue.h"
26 #include "hw/boards.h"
27 #include "hw/irq.h"
28 #include "hw/nmi.h"
29 #include "hw/qdev-properties.h"
30 #include "migration/vmstate.h"
31 
32 /*
33  * The GLUE (General Logic Unit) is an Apple custom integrated circuit chip
34  * that performs a variety of functions (RAM management, clock generation, ...).
35  * The GLUE chip receives interrupt requests from various devices,
36  * assign priority to each, and asserts one or more interrupt line to the
37  * CPU.
38  */
39 
40 /*
41  * The GLUE logic on the Quadra 800 supports 2 different IRQ routing modes
42  * controlled from the VIA1 auxmode GPIO (port B bit 6) which are documented
43  * in NetBSD as follows:
44  *
45  * A/UX mode (Linux, NetBSD, auxmode GPIO low)
46  *
47  *   Level 0:        Spurious: ignored
48  *   Level 1:        Software
49  *   Level 2:        VIA2 (except ethernet, sound)
50  *   Level 3:        Ethernet
51  *   Level 4:        Serial (SCC)
52  *   Level 5:        Sound
53  *   Level 6:        VIA1
54  *   Level 7:        NMIs: parity errors, RESET button, YANCC error
55  *
56  * Classic mode (default: used by MacOS, A/UX 3.0.1, auxmode GPIO high)
57  *
58  *   Level 0:        Spurious: ignored
59  *   Level 1:        VIA1 (clock, ADB)
60  *   Level 2:        VIA2 (NuBus, SCSI)
61  *   Level 3:
62  *   Level 4:        Serial (SCC)
63  *   Level 5:
64  *   Level 6:
65  *   Level 7:        Non-maskable: parity errors, RESET button
66  *
67  * Note that despite references to A/UX mode in Linux and NetBSD, at least
68  * A/UX 3.0.1 still uses Classic mode.
69  */
70 
71 static void GLUE_set_irq(void *opaque, int irq, int level)
72 {
73     GLUEState *s = opaque;
74     int i;
75 
76     if (s->auxmode) {
77         /* Classic mode */
78         switch (irq) {
79         case GLUE_IRQ_IN_VIA1:
80             irq = 0;
81             break;
82 
83         case GLUE_IRQ_IN_VIA2:
84             irq = 1;
85             break;
86 
87         case GLUE_IRQ_IN_SONIC:
88             /* Route to VIA2 instead */
89             qemu_set_irq(s->irqs[GLUE_IRQ_NUBUS_9], level);
90             return;
91 
92         case GLUE_IRQ_IN_ESCC:
93             irq = 3;
94             break;
95 
96         case GLUE_IRQ_IN_NMI:
97             irq = 6;
98             break;
99 
100         default:
101             g_assert_not_reached();
102         }
103     } else {
104         /* A/UX mode */
105         switch (irq) {
106         case GLUE_IRQ_IN_VIA1:
107             irq = 5;
108             break;
109 
110         case GLUE_IRQ_IN_VIA2:
111             irq = 1;
112             break;
113 
114         case GLUE_IRQ_IN_SONIC:
115             irq = 2;
116             break;
117 
118         case GLUE_IRQ_IN_ESCC:
119             irq = 3;
120             break;
121 
122         case GLUE_IRQ_IN_NMI:
123             irq = 6;
124             break;
125 
126         default:
127             g_assert_not_reached();
128         }
129     }
130 
131     if (level) {
132         s->ipr |= 1 << irq;
133     } else {
134         s->ipr &= ~(1 << irq);
135     }
136 
137     for (i = 7; i >= 0; i--) {
138         if ((s->ipr >> i) & 1) {
139             m68k_set_irq_level(s->cpu, i + 1, i + 25);
140             return;
141         }
142     }
143     m68k_set_irq_level(s->cpu, 0, 0);
144 }
145 
146 static void glue_auxmode_set_irq(void *opaque, int irq, int level)
147 {
148     GLUEState *s = GLUE(opaque);
149 
150     s->auxmode = level;
151 }
152 
153 static void glue_nmi(NMIState *n, int cpu_index, Error **errp)
154 {
155     GLUEState *s = GLUE(n);
156 
157     /* Hold NMI active for 100ms */
158     GLUE_set_irq(s, GLUE_IRQ_IN_NMI, 1);
159     timer_mod(s->nmi_release, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 100);
160 }
161 
162 static void glue_nmi_release(void *opaque)
163 {
164     GLUEState *s = GLUE(opaque);
165 
166     GLUE_set_irq(s, GLUE_IRQ_IN_NMI, 0);
167 }
168 
169 static void glue_reset(DeviceState *dev)
170 {
171     GLUEState *s = GLUE(dev);
172 
173     s->ipr = 0;
174     s->auxmode = 0;
175 
176     timer_del(s->nmi_release);
177 }
178 
179 static const VMStateDescription vmstate_glue = {
180     .name = "q800-glue",
181     .version_id = 0,
182     .minimum_version_id = 0,
183     .fields = (VMStateField[]) {
184         VMSTATE_UINT8(ipr, GLUEState),
185         VMSTATE_UINT8(auxmode, GLUEState),
186         VMSTATE_TIMER_PTR(nmi_release, GLUEState),
187         VMSTATE_END_OF_LIST(),
188     },
189 };
190 
191 /*
192  * If the m68k CPU implemented its inbound irq lines as GPIO lines
193  * rather than via the m68k_set_irq_level() function we would not need
194  * this cpu link property and could instead provide outbound IRQ lines
195  * that the board could wire up to the CPU.
196  */
197 static Property glue_properties[] = {
198     DEFINE_PROP_LINK("cpu", GLUEState, cpu, TYPE_M68K_CPU, M68kCPU *),
199     DEFINE_PROP_END_OF_LIST(),
200 };
201 
202 static void glue_finalize(Object *obj)
203 {
204     GLUEState *s = GLUE(obj);
205 
206     timer_free(s->nmi_release);
207 }
208 
209 static void glue_init(Object *obj)
210 {
211     DeviceState *dev = DEVICE(obj);
212     GLUEState *s = GLUE(dev);
213 
214     qdev_init_gpio_in(dev, GLUE_set_irq, 8);
215     qdev_init_gpio_in_named(dev, glue_auxmode_set_irq, "auxmode", 1);
216 
217     qdev_init_gpio_out(dev, s->irqs, 1);
218 
219     /* NMI release timer */
220     s->nmi_release = timer_new_ms(QEMU_CLOCK_VIRTUAL, glue_nmi_release, s);
221 }
222 
223 static void glue_class_init(ObjectClass *klass, void *data)
224 {
225     DeviceClass *dc = DEVICE_CLASS(klass);
226     NMIClass *nc = NMI_CLASS(klass);
227 
228     dc->vmsd = &vmstate_glue;
229     dc->reset = glue_reset;
230     device_class_set_props(dc, glue_properties);
231     nc->nmi_monitor_handler = glue_nmi;
232 }
233 
234 static const TypeInfo glue_info_types[] = {
235     {
236         .name = TYPE_GLUE,
237         .parent = TYPE_SYS_BUS_DEVICE,
238         .instance_size = sizeof(GLUEState),
239         .instance_init = glue_init,
240         .instance_finalize = glue_finalize,
241         .class_init = glue_class_init,
242         .interfaces = (InterfaceInfo[]) {
243              { TYPE_NMI },
244              { }
245         },
246     },
247 };
248 
249 DEFINE_TYPES(glue_info_types)
250