1/*
2 * Basic EISA bus support for the SGI Indigo-2.
3 *
4 * (C) 2002 Pascal Dameme <netinet@freesurf.fr>
5 *	and Marc Zyngier <mzyngier@freesurf.fr>
6 *
7 * This code is released under both the GPL version 2 and BSD
8 * licenses.  Either license may be used.
9 *
10 * This code offers a very basic support for this EISA bus present in
11 * the SGI Indigo-2. It currently only supports PIO (forget about DMA
12 * for the time being). This is enough for a low-end ethernet card,
13 * but forget about your favorite SCSI card...
14 *
15 * TODO :
16 * - Fix bugs...
17 * - Add ISA support
18 * - Add DMA (yeah, right...).
19 * - Fix more bugs.
20 */
21
22#include <linux/eisa.h>
23#include <linux/types.h>
24#include <linux/init.h>
25#include <linux/irq.h>
26#include <linux/kernel_stat.h>
27#include <linux/signal.h>
28#include <linux/sched.h>
29#include <linux/interrupt.h>
30#include <linux/delay.h>
31#include <asm/io.h>
32#include <asm/irq.h>
33#include <asm/mipsregs.h>
34#include <asm/addrspace.h>
35#include <asm/processor.h>
36#include <asm/sgi/ioc.h>
37#include <asm/sgi/mc.h>
38#include <asm/sgi/ip22.h>
39#include <asm/i8259.h>
40
41/* I2 has four EISA slots. */
42#define IP22_EISA_MAX_SLOTS	  4
43#define EISA_MAX_IRQ		 16
44
45#define EIU_MODE_REG	 0x0001ffc0
46#define EIU_STAT_REG	 0x0001ffc4
47#define EIU_PREMPT_REG	 0x0001ffc8
48#define EIU_QUIET_REG	 0x0001ffcc
49#define EIU_INTRPT_ACK	 0x00010004
50
51static char __init *decode_eisa_sig(unsigned long addr)
52{
53	static char sig_str[EISA_SIG_LEN] __initdata;
54	u8 sig[4];
55	u16 rev;
56	int i;
57
58	for (i = 0; i < 4; i++) {
59		sig[i] = inb(addr + i);
60
61		if (!i && (sig[0] & 0x80))
62			return NULL;
63	}
64
65	sig_str[0] = ((sig[0] >> 2) & 0x1f) + ('A' - 1);
66	sig_str[1] = (((sig[0] & 3) << 3) | (sig[1] >> 5)) + ('A' - 1);
67	sig_str[2] = (sig[1] & 0x1f) + ('A' - 1);
68	rev = (sig[2] << 8) | sig[3];
69	sprintf(sig_str + 3, "%04X", rev);
70
71	return sig_str;
72}
73
74static irqreturn_t ip22_eisa_intr(int irq, void *dev_id)
75{
76	u8 eisa_irq = inb(EIU_INTRPT_ACK);
77
78	inb(EISA_DMA1_STATUS);
79	inb(EISA_DMA2_STATUS);
80
81	if (eisa_irq < EISA_MAX_IRQ) {
82		do_IRQ(eisa_irq);
83		return IRQ_HANDLED;
84	}
85
86	/* Oops, Bad Stuff Happened... */
87	printk(KERN_ERR "eisa_irq %d out of bound\n", eisa_irq);
88
89	outb(0x20, EISA_INT2_CTRL);
90	outb(0x20, EISA_INT1_CTRL);
91
92	return IRQ_NONE;
93}
94
95static struct irqaction eisa_action = {
96	.handler	= ip22_eisa_intr,
97	.name		= "EISA",
98};
99
100int __init ip22_eisa_init(void)
101{
102	int i, c;
103	char *str;
104
105	if (!(sgimc->systemid & SGIMC_SYSID_EPRESENT)) {
106		printk(KERN_INFO "EISA: bus not present.\n");
107		return 1;
108	}
109
110	printk(KERN_INFO "EISA: Probing bus...\n");
111	for (c = 0, i = 1; i <= IP22_EISA_MAX_SLOTS; i++) {
112		if ((str = decode_eisa_sig(0x1000 * i + EISA_VENDOR_ID_OFFSET))) {
113			printk(KERN_INFO "EISA: slot %d : %s detected.\n",
114			       i, str);
115			c++;
116		}
117	}
118	printk(KERN_INFO "EISA: Detected %d card%s.\n", c, c < 2 ? "" : "s");
119#ifdef CONFIG_ISA
120	printk(KERN_INFO "ISA support compiled in.\n");
121#endif
122
123	/* Warning : BlackMagicAhead(tm).
124	   Please wave your favorite dead chicken over the busses */
125
126	/* First say hello to the EIU */
127	outl(0x0000FFFF, EIU_PREMPT_REG);
128	outl(1, EIU_QUIET_REG);
129	outl(0x40f3c07F, EIU_MODE_REG);
130
131	/* Now be nice to the EISA chipset */
132	outb(1, EISA_EXT_NMI_RESET_CTRL);
133	udelay(50);	/* Wait long enough for the dust to settle */
134	outb(0, EISA_EXT_NMI_RESET_CTRL);
135	outb(0, EISA_DMA2_WRITE_SINGLE);
136
137	init_i8259_irqs();
138
139	/* Cannot use request_irq because of kmalloc not being ready at such
140	 * an early stage. Yes, I've been bitten... */
141	setup_irq(SGI_EISA_IRQ, &eisa_action);
142
143	EISA_bus = 1;
144	return 0;
145}
146