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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 | 2 | /* |
da3fb3c9 | 3 | * Operating System Services (OSS) chip handling |
1da177e4 LT |
4 | * Written by Joshua M. Thompson (funaho@jurai.org) |
5 | * | |
6 | * | |
7 | * This chip is used in the IIfx in place of VIA #2. It acts like a fancy | |
8 | * VIA chip with prorammable interrupt levels. | |
9 | * | |
10 | * 990502 (jmt) - Major rewrite for new interrupt architecture as well as some | |
11 | * recent insights into OSS operational details. | |
0c79cf6a | 12 | * 990610 (jmt) - Now taking full advantage of the OSS. Interrupts are mapped |
1da177e4 LT |
13 | * to mostly match the A/UX interrupt scheme supported on the |
14 | * VIA side. Also added support for enabling the ISM irq again | |
15 | * since we now have a functional IOP manager. | |
16 | */ | |
17 | ||
18 | #include <linux/types.h> | |
19 | #include <linux/kernel.h> | |
20 | #include <linux/mm.h> | |
21 | #include <linux/delay.h> | |
22 | #include <linux/init.h> | |
ddc7fd25 | 23 | #include <linux/irq.h> |
1da177e4 | 24 | |
1da177e4 LT |
25 | #include <asm/macintosh.h> |
26 | #include <asm/macints.h> | |
27 | #include <asm/mac_via.h> | |
28 | #include <asm/mac_oss.h> | |
29 | ||
30 | int oss_present; | |
31 | volatile struct mac_oss *oss; | |
32 | ||
1da177e4 LT |
33 | /* |
34 | * Initialize the OSS | |
1da177e4 LT |
35 | */ |
36 | ||
37 | void __init oss_init(void) | |
38 | { | |
39 | int i; | |
40 | ||
7a0bb442 FT |
41 | if (macintosh_config->ident != MAC_MODEL_IIFX) |
42 | return; | |
1da177e4 LT |
43 | |
44 | oss = (struct mac_oss *) OSS_BASE; | |
7a0bb442 FT |
45 | pr_debug("OSS detected at %p", oss); |
46 | oss_present = 1; | |
1da177e4 LT |
47 | |
48 | /* Disable all interrupts. Unlike a VIA it looks like we */ | |
49 | /* do this by setting the source's interrupt level to zero. */ | |
50 | ||
b24f670b | 51 | for (i = 0; i < OSS_NUM_SOURCES; i++) |
da3fb3c9 | 52 | oss->irq_level[i] = 0; |
1da177e4 LT |
53 | } |
54 | ||
1da177e4 | 55 | /* |
da3fb3c9 | 56 | * Handle miscellaneous OSS interrupts. |
1da177e4 LT |
57 | */ |
58 | ||
bd0b9ac4 | 59 | static void oss_irq(struct irq_desc *desc) |
9145db56 | 60 | { |
da3fb3c9 | 61 | int events = oss->irq_pending & |
625b86ad | 62 | (OSS_IP_IOPSCC | OSS_IP_SCSI | OSS_IP_IOPISM); |
9145db56 | 63 | |
da3fb3c9 FT |
64 | if (events & OSS_IP_IOPSCC) { |
65 | oss->irq_pending &= ~OSS_IP_IOPSCC; | |
66 | generic_handle_irq(IRQ_MAC_SCC); | |
67 | } | |
68 | ||
69 | if (events & OSS_IP_SCSI) { | |
9145db56 GU |
70 | oss->irq_pending &= ~OSS_IP_SCSI; |
71 | generic_handle_irq(IRQ_MAC_SCSI); | |
da3fb3c9 FT |
72 | } |
73 | ||
74 | if (events & OSS_IP_IOPISM) { | |
75 | oss->irq_pending &= ~OSS_IP_IOPISM; | |
76 | generic_handle_irq(IRQ_MAC_ADB); | |
9145db56 GU |
77 | } |
78 | } | |
1da177e4 LT |
79 | |
80 | /* | |
81 | * Nubus IRQ handler, OSS style | |
82 | * | |
83 | * Unlike the VIA/RBV this is on its own autovector interrupt level. | |
84 | */ | |
85 | ||
bd0b9ac4 | 86 | static void oss_nubus_irq(struct irq_desc *desc) |
9145db56 GU |
87 | { |
88 | int events, irq_bit, i; | |
89 | ||
90 | events = oss->irq_pending & OSS_IP_NUBUS; | |
91 | if (!events) | |
92 | return; | |
93 | ||
9145db56 GU |
94 | /* There are only six slots on the OSS, not seven */ |
95 | ||
96 | i = 6; | |
97 | irq_bit = 0x40; | |
98 | do { | |
99 | --i; | |
100 | irq_bit >>= 1; | |
101 | if (events & irq_bit) { | |
102 | oss->irq_pending &= ~irq_bit; | |
103 | generic_handle_irq(NUBUS_SOURCE_BASE + i); | |
104 | } | |
105 | } while(events & (irq_bit - 1)); | |
106 | } | |
9145db56 GU |
107 | |
108 | /* | |
109 | * Register the OSS and NuBus interrupt dispatchers. | |
da3fb3c9 FT |
110 | * |
111 | * This IRQ mapping is laid out with two things in mind: first, we try to keep | |
112 | * things on their own levels to avoid having to do double-dispatches. Second, | |
113 | * the levels match as closely as possible the alternate IRQ mapping mode (aka | |
114 | * "A/UX mode") available on some VIA machines. | |
9145db56 GU |
115 | */ |
116 | ||
da3fb3c9 FT |
117 | #define OSS_IRQLEV_IOPISM IRQ_AUTO_1 |
118 | #define OSS_IRQLEV_SCSI IRQ_AUTO_2 | |
119 | #define OSS_IRQLEV_NUBUS IRQ_AUTO_3 | |
120 | #define OSS_IRQLEV_IOPSCC IRQ_AUTO_4 | |
121 | #define OSS_IRQLEV_VIA1 IRQ_AUTO_6 | |
122 | ||
9145db56 GU |
123 | void __init oss_register_interrupts(void) |
124 | { | |
da3fb3c9 FT |
125 | irq_set_chained_handler(OSS_IRQLEV_IOPISM, oss_irq); |
126 | irq_set_chained_handler(OSS_IRQLEV_SCSI, oss_irq); | |
127 | irq_set_chained_handler(OSS_IRQLEV_NUBUS, oss_nubus_irq); | |
128 | irq_set_chained_handler(OSS_IRQLEV_IOPSCC, oss_irq); | |
129 | irq_set_chained_handler(OSS_IRQLEV_VIA1, via1_irq); | |
130 | ||
131 | /* OSS_VIA1 gets enabled here because it has no machspec interrupt. */ | |
132 | oss->irq_level[OSS_VIA1] = IRQ_AUTO_6; | |
9145db56 | 133 | } |
1da177e4 LT |
134 | |
135 | /* | |
136 | * Enable an OSS interrupt | |
137 | * | |
138 | * It looks messy but it's rather straightforward. The switch() statement | |
139 | * just maps the machspec interrupt numbers to the right OSS interrupt | |
140 | * source (if the OSS handles that interrupt) and then sets the interrupt | |
141 | * level for that source to nonzero, thus enabling the interrupt. | |
142 | */ | |
143 | ||
144 | void oss_irq_enable(int irq) { | |
1da177e4 | 145 | switch(irq) { |
80614e5a | 146 | case IRQ_MAC_SCC: |
1da177e4 | 147 | oss->irq_level[OSS_IOPSCC] = OSS_IRQLEV_IOPSCC; |
da3fb3c9 | 148 | return; |
1da177e4 LT |
149 | case IRQ_MAC_ADB: |
150 | oss->irq_level[OSS_IOPISM] = OSS_IRQLEV_IOPISM; | |
da3fb3c9 | 151 | return; |
1da177e4 LT |
152 | case IRQ_MAC_SCSI: |
153 | oss->irq_level[OSS_SCSI] = OSS_IRQLEV_SCSI; | |
da3fb3c9 | 154 | return; |
1da177e4 LT |
155 | case IRQ_NUBUS_9: |
156 | case IRQ_NUBUS_A: | |
157 | case IRQ_NUBUS_B: | |
158 | case IRQ_NUBUS_C: | |
159 | case IRQ_NUBUS_D: | |
160 | case IRQ_NUBUS_E: | |
161 | irq -= NUBUS_SOURCE_BASE; | |
162 | oss->irq_level[irq] = OSS_IRQLEV_NUBUS; | |
da3fb3c9 | 163 | return; |
1da177e4 | 164 | } |
da3fb3c9 FT |
165 | |
166 | if (IRQ_SRC(irq) == 1) | |
167 | via_irq_enable(irq); | |
1da177e4 LT |
168 | } |
169 | ||
170 | /* | |
171 | * Disable an OSS interrupt | |
172 | * | |
173 | * Same as above except we set the source's interrupt level to zero, | |
174 | * to disable the interrupt. | |
175 | */ | |
176 | ||
177 | void oss_irq_disable(int irq) { | |
1da177e4 | 178 | switch(irq) { |
80614e5a | 179 | case IRQ_MAC_SCC: |
da3fb3c9 FT |
180 | oss->irq_level[OSS_IOPSCC] = 0; |
181 | return; | |
1da177e4 | 182 | case IRQ_MAC_ADB: |
da3fb3c9 FT |
183 | oss->irq_level[OSS_IOPISM] = 0; |
184 | return; | |
1da177e4 | 185 | case IRQ_MAC_SCSI: |
da3fb3c9 FT |
186 | oss->irq_level[OSS_SCSI] = 0; |
187 | return; | |
1da177e4 LT |
188 | case IRQ_NUBUS_9: |
189 | case IRQ_NUBUS_A: | |
190 | case IRQ_NUBUS_B: | |
191 | case IRQ_NUBUS_C: | |
192 | case IRQ_NUBUS_D: | |
193 | case IRQ_NUBUS_E: | |
194 | irq -= NUBUS_SOURCE_BASE; | |
da3fb3c9 FT |
195 | oss->irq_level[irq] = 0; |
196 | return; | |
1da177e4 | 197 | } |
da3fb3c9 FT |
198 | |
199 | if (IRQ_SRC(irq) == 1) | |
200 | via_irq_disable(irq); | |
1da177e4 | 201 | } |