psc.c

  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#include "mac.h"
 30
 31#define DEBUG_PSC
 32
 33volatile __u8 *psc;
 34EXPORT_SYMBOL_GPL(psc);
 35
 36/*
 37 * Debugging dump, used in various places to see what's going on.
 38 */
 39
 40static void psc_debug_dump(void)
 41{
 42	int	i;
 43
 44	if (!psc)
 45		return;
 46
 47	for (i = 0x30 ; i < 0x70 ; i += 0x10) {
 48		printk(KERN_DEBUG "PSC #%d:  IFR = 0x%02X IER = 0x%02X\n",
 49			i >> 4,
 50			(int) psc_read_byte(pIFRbase + i),
 51			(int) psc_read_byte(pIERbase + i));
 52	}
 53}
 54
 55/*
 56 * Try to kill all DMA channels on the PSC. Not sure how this his
 57 * supposed to work; this is code lifted from macmace.c and then
 58 * expanded to cover what I think are the other 7 channels.
 59 */
 60
 61static __init void psc_dma_die_die_die(void)
 62{
 63	int i;
 64
 65	for (i = 0 ; i < 9 ; i++) {
 66		psc_write_word(PSC_CTL_BASE + (i << 4), 0x8800);
 67		psc_write_word(PSC_CTL_BASE + (i << 4), 0x1000);
 68		psc_write_word(PSC_CMD_BASE + (i << 5), 0x1100);
 69		psc_write_word(PSC_CMD_BASE + (i << 5) + 0x10, 0x1100);
 70	}
 71}
 72
 73/*
 74 * Initialize the PSC. For now this just involves shutting down all
 75 * interrupt sources using the IERs.
 76 */
 77
 78void __init psc_init(void)
 79{
 80	int i;
 81
 82	if (macintosh_config->ident != MAC_MODEL_C660
 83	 && macintosh_config->ident != MAC_MODEL_Q840)
 84	{
 85		psc = NULL;
 86		return;
 87	}
 88
 89	/*
 90	 * The PSC is always at the same spot, but using psc
 91	 * keeps things consistent with the psc_xxxx functions.
 92	 */
 93
 94	psc = (void *) PSC_BASE;
 95
 96	pr_debug("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	events = psc_read_byte(pIFR) & psc_read_byte(pIER) & 0xF;
127	if (!events)
128		return;
129
130	irq_num = irq << 3;
131	irq_bit = 1;
132	do {
133		if (events & irq_bit) {
134			psc_write_byte(pIFR, irq_bit);
135			generic_handle_irq(irq_num);
136		}
137		irq_num++;
138		irq_bit <<= 1;
139	} while (events >= irq_bit);
140}
141
142/*
143 * Register the PSC interrupt dispatchers for autovector interrupts 3-6.
144 */
145
146void __init psc_register_interrupts(void)
147{
148	irq_set_chained_handler_and_data(IRQ_AUTO_3, psc_irq, (void *)0x30);
149	irq_set_chained_handler_and_data(IRQ_AUTO_4, psc_irq, (void *)0x40);
150	irq_set_chained_handler_and_data(IRQ_AUTO_5, psc_irq, (void *)0x50);
151	irq_set_chained_handler_and_data(IRQ_AUTO_6, psc_irq, (void *)0x60);
152}
153
154void psc_irq_enable(int irq) {
155	int irq_src	= IRQ_SRC(irq);
156	int irq_idx	= IRQ_IDX(irq);
157	int pIER	= pIERbase + (irq_src << 4);
158
159	psc_write_byte(pIER, (1 << irq_idx) | 0x80);
160}
161
162void psc_irq_disable(int irq) {
163	int irq_src	= IRQ_SRC(irq);
164	int irq_idx	= IRQ_IDX(irq);
165	int pIER	= pIERbase + (irq_src << 4);
166
167	psc_write_byte(pIER, 1 << irq_idx);
168}