xref: /openbmc/linux/arch/mips/sgi-ip22/ip22-eisa.c (revision ac8fd122)
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 
decode_eisa_sig(unsigned long addr)51 static 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 
ip22_eisa_intr(int irq,void * dev_id)74 static 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 
ip22_eisa_init(void)95 int __init ip22_eisa_init(void)
96 {
97 	int i, c;
98 	char *str;
99 
100 	if (!(sgimc->systemid & SGIMC_SYSID_EPRESENT)) {
101 		printk(KERN_INFO "EISA: bus not present.\n");
102 		return 1;
103 	}
104 
105 	printk(KERN_INFO "EISA: Probing bus...\n");
106 	for (c = 0, i = 1; i <= IP22_EISA_MAX_SLOTS; i++) {
107 		if ((str = decode_eisa_sig(0x1000 * i + EISA_VENDOR_ID_OFFSET))) {
108 			printk(KERN_INFO "EISA: slot %d : %s detected.\n",
109 			       i, str);
110 			c++;
111 		}
112 	}
113 	printk(KERN_INFO "EISA: Detected %d card%s.\n", c, c < 2 ? "" : "s");
114 #ifdef CONFIG_ISA
115 	printk(KERN_INFO "ISA support compiled in.\n");
116 #endif
117 
118 	/* Warning : BlackMagicAhead(tm).
119 	   Please wave your favorite dead chicken over the busses */
120 
121 	/* First say hello to the EIU */
122 	outl(0x0000FFFF, EIU_PREMPT_REG);
123 	outl(1, EIU_QUIET_REG);
124 	outl(0x40f3c07F, EIU_MODE_REG);
125 
126 	/* Now be nice to the EISA chipset */
127 	outb(1, EISA_EXT_NMI_RESET_CTRL);
128 	udelay(50);	/* Wait long enough for the dust to settle */
129 	outb(0, EISA_EXT_NMI_RESET_CTRL);
130 	outb(0, EISA_DMA2_WRITE_SINGLE);
131 
132 	init_i8259_irqs();
133 
134 	if (request_irq(SGI_EISA_IRQ, ip22_eisa_intr, 0, "EISA", NULL))
135 		pr_err("Failed to request irq %d (EISA)\n", SGI_EISA_IRQ);
136 
137 	EISA_bus = 1;
138 	return 0;
139 }
140