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;
32EXPORT_SYMBOL_GPL(psc);
33
34/*
35 * Debugging dump, used in various places to see what's going on.
36 */
37
38static 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
57static __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
76void __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
117static 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
151void __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
159void 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
170void 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