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;
77 u8 dma1, dma2;
78
79 eisa_irq = inb(EIU_INTRPT_ACK);
80 dma1 = inb(EISA_DMA1_STATUS);
81 dma2 = inb(EISA_DMA2_STATUS);
82
83 if (eisa_irq < EISA_MAX_IRQ) {
84 do_IRQ(eisa_irq);
85 return IRQ_HANDLED;
86 }
87
88 /* Oops, Bad Stuff Happened... */
89 printk(KERN_ERR "eisa_irq %d out of bound\n", eisa_irq);
90
91 outb(0x20, EISA_INT2_CTRL);
92 outb(0x20, EISA_INT1_CTRL);
93
94 return IRQ_NONE;
95 }
96
97 static struct irqaction eisa_action = {
98 .handler = ip22_eisa_intr,
99 .name = "EISA",
100 };
101
ip22_eisa_init(void)102 int __init ip22_eisa_init(void)
103 {
104 int i, c;
105 char *str;
106
107 if (!(sgimc->systemid & SGIMC_SYSID_EPRESENT)) {
108 printk(KERN_INFO "EISA: bus not present.\n");
109 return 1;
110 }
111
112 printk(KERN_INFO "EISA: Probing bus...\n");
113 for (c = 0, i = 1; i <= IP22_EISA_MAX_SLOTS; i++) {
114 if ((str = decode_eisa_sig(0x1000 * i + EISA_VENDOR_ID_OFFSET))) {
115 printk(KERN_INFO "EISA: slot %d : %s detected.\n",
116 i, str);
117 c++;
118 }
119 }
120 printk(KERN_INFO "EISA: Detected %d card%s.\n", c, c < 2 ? "" : "s");
121 #ifdef CONFIG_ISA
122 printk(KERN_INFO "ISA support compiled in.\n");
123 #endif
124
125 /* Warning : BlackMagicAhead(tm).
126 Please wave your favorite dead chicken over the busses */
127
128 /* First say hello to the EIU */
129 outl(0x0000FFFF, EIU_PREMPT_REG);
130 outl(1, EIU_QUIET_REG);
131 outl(0x40f3c07F, EIU_MODE_REG);
132
133 /* Now be nice to the EISA chipset */
134 outb(1, EISA_EXT_NMI_RESET_CTRL);
135 udelay(50); /* Wait long enough for the dust to settle */
136 outb(0, EISA_EXT_NMI_RESET_CTRL);
137 outb(0, EISA_DMA2_WRITE_SINGLE);
138
139 init_i8259_irqs();
140
141 /* Cannot use request_irq because of kmalloc not being ready at such
142 * an early stage. Yes, I've been bitten... */
143 setup_irq(SGI_EISA_IRQ, &eisa_action);
144
145 EISA_bus = 1;
146 return 0;
147 }
148