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
30int psc_present;
31volatile __u8 *psc;
32
33/*
34 * Debugging dump, used in various places to see what's going on.
35 */
36
37static void psc_debug_dump(void)
38{
39	int	i;
40
41	if (!psc_present) return;
42	for (i = 0x30 ; i < 0x70 ; i += 0x10) {
43		printk("PSC #%d:  IFR = 0x%02X IER = 0x%02X\n",
44			i >> 4,
45			(int) psc_read_byte(pIFRbase + i),
46			(int) psc_read_byte(pIERbase + i));
47	}
48}
49
50/*
51 * Try to kill all DMA channels on the PSC. Not sure how this his
52 * supposed to work; this is code lifted from macmace.c and then
53 * expanded to cover what I think are the other 7 channels.
54 */
55
56static __init void psc_dma_die_die_die(void)
57{
58	int i;
59
60	printk("Killing all PSC DMA channels...");
61	for (i = 0 ; i < 9 ; i++) {
62		psc_write_word(PSC_CTL_BASE + (i << 4), 0x8800);
63		psc_write_word(PSC_CTL_BASE + (i << 4), 0x1000);
64		psc_write_word(PSC_CMD_BASE + (i << 5), 0x1100);
65		psc_write_word(PSC_CMD_BASE + (i << 5) + 0x10, 0x1100);
66	}
67	printk("done!\n");
68}
69
70/*
71 * Initialize the PSC. For now this just involves shutting down all
72 * interrupt sources using the IERs.
73 */
74
75void __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		psc_present = 0;
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	psc_present = 1;
94
95	printk("PSC detected at %p\n", psc);
96
97	psc_dma_die_die_die();
98
99#ifdef DEBUG_PSC
100	psc_debug_dump();
101#endif
102	/*
103	 * Mask and clear all possible interrupts
104	 */
105
106	for (i = 0x30 ; i < 0x70 ; i += 0x10) {
107		psc_write_byte(pIERbase + i, 0x0F);
108		psc_write_byte(pIFRbase + i, 0x0F);
109	}
110}
111
112/*
113 * PSC interrupt handler. It's a lot like the VIA interrupt handler.
114 */
115
116static void psc_irq(unsigned int irq, struct irq_desc *desc)
117{
118	unsigned int offset = (unsigned int)irq_desc_get_handler_data(desc);
119	int pIFR	= pIFRbase + offset;
120	int pIER	= pIERbase + offset;
121	int irq_num;
122	unsigned char irq_bit, events;
123
124#ifdef DEBUG_IRQS
125	printk("psc_irq: irq %u pIFR = 0x%02X pIER = 0x%02X\n",
126		irq, (int) psc_read_byte(pIFR), (int) psc_read_byte(pIER));
127#endif
128
129	events = psc_read_byte(pIFR) & psc_read_byte(pIER) & 0xF;
130	if (!events)
131		return;
132
133	irq_num = irq << 3;
134	irq_bit = 1;
135	do {
136		if (events & irq_bit) {
137			psc_write_byte(pIFR, irq_bit);
138			generic_handle_irq(irq_num);
139		}
140		irq_num++;
141		irq_bit <<= 1;
142	} while (events >= irq_bit);
143}
144
145/*
146 * Register the PSC interrupt dispatchers for autovector interrupts 3-6.
147 */
148
149void __init psc_register_interrupts(void)
150{
151	irq_set_chained_handler(IRQ_AUTO_3, psc_irq);
152	irq_set_handler_data(IRQ_AUTO_3, (void *)0x30);
153	irq_set_chained_handler(IRQ_AUTO_4, psc_irq);
154	irq_set_handler_data(IRQ_AUTO_4, (void *)0x40);
155	irq_set_chained_handler(IRQ_AUTO_5, psc_irq);
156	irq_set_handler_data(IRQ_AUTO_5, (void *)0x50);
157	irq_set_chained_handler(IRQ_AUTO_6, psc_irq);
158	irq_set_handler_data(IRQ_AUTO_6, (void *)0x60);
159}
160
161void psc_irq_enable(int irq) {
162	int irq_src	= IRQ_SRC(irq);
163	int irq_idx	= IRQ_IDX(irq);
164	int pIER	= pIERbase + (irq_src << 4);
165
166#ifdef DEBUG_IRQUSE
167	printk("psc_irq_enable(%d)\n", irq);
168#endif
169	psc_write_byte(pIER, (1 << irq_idx) | 0x80);
170}
171
172void psc_irq_disable(int irq) {
173	int irq_src	= IRQ_SRC(irq);
174	int irq_idx	= IRQ_IDX(irq);
175	int pIER	= pIERbase + (irq_src << 4);
176
177#ifdef DEBUG_IRQUSE
178	printk("psc_irq_disable(%d)\n", irq);
179#endif
180	psc_write_byte(pIER, 1 << irq_idx);
181}
182