1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Apple Peripheral System Controller (PSC)
4 *
5 * The PSC is used on the AV Macs to control IO functions not handled
6 * by the VIAs (Ethernet, DSP, SCC).
7 *
8 * TO DO:
9 *
10 * Try to figure out what's going on in pIFR5 and pIFR6. There seem to be
11 * persisant interrupt conditions in those registers and I have no idea what
12 * they are. Granted it doesn't affect since we're not enabling any interrupts
13 * on those levels at the moment, but it would be nice to know. I have a feeling
14 * they aren't actually interrupt lines but data lines (to the DSP?)
15 */
16
17 #include <linux/types.h>
18 #include <linux/kernel.h>
19 #include <linux/mm.h>
20 #include <linux/delay.h>
21 #include <linux/init.h>
22 #include <linux/irq.h>
23
24 #include <asm/traps.h>
25 #include <asm/macintosh.h>
26 #include <asm/macints.h>
27 #include <asm/mac_psc.h>
28
29 #include "mac.h"
30
31 #define DEBUG_PSC
32
33 volatile __u8 *psc;
34 EXPORT_SYMBOL_GPL(psc);
35
36 /*
37 * Debugging dump, used in various places to see what's going on.
38 */
39
40 static void psc_debug_dump(void)
41 {
42 int i;
43
44 if (!psc)
45 return;
46
47 for (i = 0x30 ; i < 0x70 ; i += 0x10) {
48 printk(KERN_DEBUG "PSC #%d: IFR = 0x%02X IER = 0x%02X\n",
49 i >> 4,
50 (int) psc_read_byte(pIFRbase + i),
51 (int) psc_read_byte(pIERbase + i));
52 }
53 }
54
55 /*
56 * Try to kill all DMA channels on the PSC. Not sure how this his
57 * supposed to work; this is code lifted from macmace.c and then
58 * expanded to cover what I think are the other 7 channels.
59 */
60
61 static __init void psc_dma_die_die_die(void)
62 {
63 int i;
64
65 for (i = 0 ; i < 9 ; i++) {
66 psc_write_word(PSC_CTL_BASE + (i << 4), 0x8800);
67 psc_write_word(PSC_CTL_BASE + (i << 4), 0x1000);
68 psc_write_word(PSC_CMD_BASE + (i << 5), 0x1100);
69 psc_write_word(PSC_CMD_BASE + (i << 5) + 0x10, 0x1100);
70 }
71 }
72
73 /*
74 * Initialize the PSC. For now this just involves shutting down all
75 * interrupt sources using the IERs.
76 */
77
78 void __init psc_init(void)
79 {
80 int i;
81
82 if (macintosh_config->ident != MAC_MODEL_C660
83 && macintosh_config->ident != MAC_MODEL_Q840)
84 {
85 psc = NULL;
86 return;
87 }
88
89 /*
90 * The PSC is always at the same spot, but using psc
91 * keeps things consistent with the psc_xxxx functions.
92 */
93
94 psc = (void *) PSC_BASE;
95
96 pr_debug("PSC detected at %p\n", psc);
97
98 psc_dma_die_die_die();
99
100 #ifdef DEBUG_PSC
101 psc_debug_dump();
102 #endif
103 /*
104 * Mask and clear all possible interrupts
105 */
106
107 for (i = 0x30 ; i < 0x70 ; i += 0x10) {
108 psc_write_byte(pIERbase + i, 0x0F);
109 psc_write_byte(pIFRbase + i, 0x0F);
110 }
111 }
112
113 /*
114 * PSC interrupt handler. It's a lot like the VIA interrupt handler.
115 */
116
117 static void psc_irq(struct irq_desc *desc)
118 {
119 unsigned int offset = (unsigned int)irq_desc_get_handler_data(desc);
120 unsigned int irq = irq_desc_get_irq(desc);
121 int pIFR = pIFRbase + offset;
122 int pIER = pIERbase + offset;
123 int irq_num;
124 unsigned char irq_bit, events;
125
126 events = psc_read_byte(pIFR) & psc_read_byte(pIER) & 0xF;
127 if (!events)
128 return;
129
130 irq_num = irq << 3;
131 irq_bit = 1;
132 do {
133 if (events & irq_bit) {
134 psc_write_byte(pIFR, irq_bit);
135 generic_handle_irq(irq_num);
136 }
137 irq_num++;
138 irq_bit <<= 1;
139 } while (events >= irq_bit);
140 }
141
142 /*
143 * Register the PSC interrupt dispatchers for autovector interrupts 3-6.
144 */
145
146 void __init psc_register_interrupts(void)
147 {
148 irq_set_chained_handler_and_data(IRQ_AUTO_3, psc_irq, (void *)0x30);
149 irq_set_chained_handler_and_data(IRQ_AUTO_4, psc_irq, (void *)0x40);
150 irq_set_chained_handler_and_data(IRQ_AUTO_5, psc_irq, (void *)0x50);
151 irq_set_chained_handler_and_data(IRQ_AUTO_6, psc_irq, (void *)0x60);
152 }
153
154 void psc_irq_enable(int irq) {
155 int irq_src = IRQ_SRC(irq);
156 int irq_idx = IRQ_IDX(irq);
157 int pIER = pIERbase + (irq_src << 4);
158
159 psc_write_byte(pIER, (1 << irq_idx) | 0x80);
160 }
161
162 void psc_irq_disable(int irq) {
163 int irq_src = IRQ_SRC(irq);
164 int irq_idx = IRQ_IDX(irq);
165 int pIER = pIERbase + (irq_src << 4);
166
167 psc_write_byte(pIER, 1 << irq_idx);
168 }
169
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