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