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 int psc_present;
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_present) return;
43 for (i = 0x30 ; i < 0x70 ; i += 0x10) {
44 printk("PSC #%d: IFR = 0x%02X IER = 0x%02X\n",
45 i >> 4,
46 (int) psc_read_byte(pIFRbase + i),
47 (int) psc_read_byte(pIERbase + i));
48 }
49 }
50
51 /*
52 * Try to kill all DMA channels on the PSC. Not sure how this his
53 * supposed to work; this is code lifted from macmace.c and then
54 * expanded to cover what I think are the other 7 channels.
55 */
56
psc_dma_die_die_die(void)57 static __init void psc_dma_die_die_die(void)
58 {
59 int i;
60
61 printk("Killing all PSC DMA channels...");
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 printk("done!\n");
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 psc_present = 0;
85 return;
86 }
87
88 /*
89 * The PSC is always at the same spot, but using psc
90 * keeps things consistent with the psc_xxxx functions.
91 */
92
93 psc = (void *) PSC_BASE;
94 psc_present = 1;
95
96 printk("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
psc_irq(struct irq_desc * desc)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 #ifdef DEBUG_IRQS
127 printk("psc_irq: irq %u pIFR = 0x%02X pIER = 0x%02X\n",
128 irq, (int) psc_read_byte(pIFR), (int) psc_read_byte(pIER));
129 #endif
130
131 events = psc_read_byte(pIFR) & psc_read_byte(pIER) & 0xF;
132 if (!events)
133 return;
134
135 irq_num = irq << 3;
136 irq_bit = 1;
137 do {
138 if (events & irq_bit) {
139 psc_write_byte(pIFR, irq_bit);
140 generic_handle_irq(irq_num);
141 }
142 irq_num++;
143 irq_bit <<= 1;
144 } while (events >= irq_bit);
145 }
146
147 /*
148 * Register the PSC interrupt dispatchers for autovector interrupts 3-6.
149 */
150
psc_register_interrupts(void)151 void __init psc_register_interrupts(void)
152 {
153 irq_set_chained_handler_and_data(IRQ_AUTO_3, psc_irq, (void *)0x30);
154 irq_set_chained_handler_and_data(IRQ_AUTO_4, psc_irq, (void *)0x40);
155 irq_set_chained_handler_and_data(IRQ_AUTO_5, psc_irq, (void *)0x50);
156 irq_set_chained_handler_and_data(IRQ_AUTO_6, psc_irq, (void *)0x60);
157 }
158
psc_irq_enable(int irq)159 void psc_irq_enable(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 #ifdef DEBUG_IRQUSE
165 printk("psc_irq_enable(%d)\n", irq);
166 #endif
167 psc_write_byte(pIER, (1 << irq_idx) | 0x80);
168 }
169
psc_irq_disable(int irq)170 void psc_irq_disable(int irq) {
171 int irq_src = IRQ_SRC(irq);
172 int irq_idx = IRQ_IDX(irq);
173 int pIER = pIERbase + (irq_src << 4);
174
175 #ifdef DEBUG_IRQUSE
176 printk("psc_irq_disable(%d)\n", irq);
177 #endif
178 psc_write_byte(pIER, 1 << irq_idx);
179 }
180