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 #define DEBUG_PSC
30
31 volatile __u8 *psc;
32 EXPORT_SYMBOL_GPL(psc);
33
34 /*
35 * Debugging dump, used in various places to see what's going on.
36 */
37
psc_debug_dump(void)38 static void psc_debug_dump(void)
39 {
40 int i;
41
42 if (!psc)
43 return;
44
45 for (i = 0x30 ; i < 0x70 ; i += 0x10) {
46 printk(KERN_DEBUG "PSC #%d: IFR = 0x%02X IER = 0x%02X\n",
47 i >> 4,
48 (int) psc_read_byte(pIFRbase + i),
49 (int) psc_read_byte(pIERbase + i));
50 }
51 }
52
53 /*
54 * Try to kill all DMA channels on the PSC. Not sure how this his
55 * supposed to work; this is code lifted from macmace.c and then
56 * expanded to cover what I think are the other 7 channels.
57 */
58
psc_dma_die_die_die(void)59 static __init void psc_dma_die_die_die(void)
60 {
61 int i;
62
63 for (i = 0 ; i < 9 ; i++) {
64 psc_write_word(PSC_CTL_BASE + (i << 4), 0x8800);
65 psc_write_word(PSC_CTL_BASE + (i << 4), 0x1000);
66 psc_write_word(PSC_CMD_BASE + (i << 5), 0x1100);
67 psc_write_word(PSC_CMD_BASE + (i << 5) + 0x10, 0x1100);
68 }
69 }
70
71 /*
72 * Initialize the PSC. For now this just involves shutting down all
73 * interrupt sources using the IERs.
74 */
75
psc_init(void)76 void __init psc_init(void)
77 {
78 int i;
79
80 if (macintosh_config->ident != MAC_MODEL_C660
81 && macintosh_config->ident != MAC_MODEL_Q840)
82 {
83 psc = NULL;
84 return;
85 }
86
87 /*
88 * The PSC is always at the same spot, but using psc
89 * keeps things consistent with the psc_xxxx functions.
90 */
91
92 psc = (void *) PSC_BASE;
93
94 pr_debug("PSC detected at %p\n", psc);
95
96 psc_dma_die_die_die();
97
98 #ifdef DEBUG_PSC
99 psc_debug_dump();
100 #endif
101 /*
102 * Mask and clear all possible interrupts
103 */
104
105 for (i = 0x30 ; i < 0x70 ; i += 0x10) {
106 psc_write_byte(pIERbase + i, 0x0F);
107 psc_write_byte(pIFRbase + i, 0x0F);
108 }
109 }
110
111 /*
112 * PSC interrupt handler. It's a lot like the VIA interrupt handler.
113 */
114
psc_irq(struct irq_desc * desc)115 static void psc_irq(struct irq_desc *desc)
116 {
117 unsigned int offset = (unsigned int)irq_desc_get_handler_data(desc);
118 unsigned int irq = irq_desc_get_irq(desc);
119 int pIFR = pIFRbase + offset;
120 int pIER = pIERbase + offset;
121 int irq_num;
122 unsigned char irq_bit, events;
123
124 events = psc_read_byte(pIFR) & psc_read_byte(pIER) & 0xF;
125 if (!events)
126 return;
127
128 irq_num = irq << 3;
129 irq_bit = 1;
130 do {
131 if (events & irq_bit) {
132 psc_write_byte(pIFR, irq_bit);
133 generic_handle_irq(irq_num);
134 }
135 irq_num++;
136 irq_bit <<= 1;
137 } while (events >= irq_bit);
138 }
139
140 /*
141 * Register the PSC interrupt dispatchers for autovector interrupts 3-6.
142 */
143
psc_register_interrupts(void)144 void __init psc_register_interrupts(void)
145 {
146 irq_set_chained_handler_and_data(IRQ_AUTO_3, psc_irq, (void *)0x30);
147 irq_set_chained_handler_and_data(IRQ_AUTO_4, psc_irq, (void *)0x40);
148 irq_set_chained_handler_and_data(IRQ_AUTO_5, psc_irq, (void *)0x50);
149 irq_set_chained_handler_and_data(IRQ_AUTO_6, psc_irq, (void *)0x60);
150 }
151
psc_irq_enable(int irq)152 void psc_irq_enable(int irq) {
153 int irq_src = IRQ_SRC(irq);
154 int irq_idx = IRQ_IDX(irq);
155 int pIER = pIERbase + (irq_src << 4);
156
157 psc_write_byte(pIER, (1 << irq_idx) | 0x80);
158 }
159
psc_irq_disable(int irq)160 void psc_irq_disable(int irq) {
161 int irq_src = IRQ_SRC(irq);
162 int irq_idx = IRQ_IDX(irq);
163 int pIER = pIERbase + (irq_src << 4);
164
165 psc_write_byte(pIER, 1 << irq_idx);
166 }
167