1 /*
2 * udbg for zilog scc ports as found on Apple PowerMacs
3 *
4 * Copyright (C) 2001-2005 PPC 64 Team, IBM Corp
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11 #include <linux/types.h>
12 #include <asm/udbg.h>
13 #include <asm/processor.h>
14 #include <asm/io.h>
15 #include <asm/prom.h>
16 #include <asm/pmac_feature.h>
17
18 extern u8 real_readb(volatile u8 __iomem *addr);
19 extern void real_writeb(u8 data, volatile u8 __iomem *addr);
20
21 #define SCC_TXRDY 4
22 #define SCC_RXRDY 1
23
24 static volatile u8 __iomem *sccc;
25 static volatile u8 __iomem *sccd;
26
udbg_scc_putc(char c)27 static void udbg_scc_putc(char c)
28 {
29 if (sccc) {
30 while ((in_8(sccc) & SCC_TXRDY) == 0)
31 ;
32 out_8(sccd, c);
33 if (c == '\n')
34 udbg_scc_putc('\r');
35 }
36 }
37
udbg_scc_getc_poll(void)38 static int udbg_scc_getc_poll(void)
39 {
40 if (sccc) {
41 if ((in_8(sccc) & SCC_RXRDY) != 0)
42 return in_8(sccd);
43 else
44 return -1;
45 }
46 return -1;
47 }
48
udbg_scc_getc(void)49 static int udbg_scc_getc(void)
50 {
51 if (sccc) {
52 while ((in_8(sccc) & SCC_RXRDY) == 0)
53 ;
54 return in_8(sccd);
55 }
56 return -1;
57 }
58
59 static unsigned char scc_inittab[] = {
60 13, 0, /* set baud rate divisor */
61 12, 0,
62 14, 1, /* baud rate gen enable, src=rtxc */
63 11, 0x50, /* clocks = br gen */
64 5, 0xea, /* tx 8 bits, assert DTR & RTS */
65 4, 0x46, /* x16 clock, 1 stop */
66 3, 0xc1, /* rx enable, 8 bits */
67 };
68
udbg_scc_init(int force_scc)69 void udbg_scc_init(int force_scc)
70 {
71 const u32 *reg;
72 unsigned long addr;
73 struct device_node *stdout = NULL, *escc = NULL, *macio = NULL;
74 struct device_node *ch, *ch_def = NULL, *ch_a = NULL;
75 const char *path;
76 int i;
77
78 escc = of_find_node_by_name(NULL, "escc");
79 if (escc == NULL)
80 goto bail;
81 macio = of_get_parent(escc);
82 if (macio == NULL)
83 goto bail;
84 path = of_get_property(of_chosen, "linux,stdout-path", NULL);
85 if (path != NULL)
86 stdout = of_find_node_by_path(path);
87 for (ch = NULL; (ch = of_get_next_child(escc, ch)) != NULL;) {
88 if (ch == stdout)
89 ch_def = of_node_get(ch);
90 if (strcmp(ch->name, "ch-a") == 0)
91 ch_a = of_node_get(ch);
92 }
93 if (ch_def == NULL && !force_scc)
94 goto bail;
95
96 ch = ch_def ? ch_def : ch_a;
97
98 /* Get address within mac-io ASIC */
99 reg = of_get_property(escc, "reg", NULL);
100 if (reg == NULL)
101 goto bail;
102 addr = reg[0];
103
104 /* Get address of mac-io PCI itself */
105 reg = of_get_property(macio, "assigned-addresses", NULL);
106 if (reg == NULL)
107 goto bail;
108 addr += reg[2];
109
110 /* Lock the serial port */
111 pmac_call_feature(PMAC_FTR_SCC_ENABLE, ch,
112 PMAC_SCC_ASYNC | PMAC_SCC_FLAG_XMON, 1);
113
114 if (ch == ch_a)
115 addr += 0x20;
116 sccc = ioremap(addr & PAGE_MASK, PAGE_SIZE) ;
117 sccc += addr & ~PAGE_MASK;
118 sccd = sccc + 0x10;
119
120 mb();
121
122 for (i = 20000; i != 0; --i)
123 in_8(sccc);
124 out_8(sccc, 0x09); /* reset A or B side */
125 out_8(sccc, 0xc0);
126
127 /* If SCC was the OF output port, read the BRG value, else
128 * Setup for 38400 or 57600 8N1 depending on the machine
129 */
130 if (ch_def != NULL) {
131 out_8(sccc, 13);
132 scc_inittab[1] = in_8(sccc);
133 out_8(sccc, 12);
134 scc_inittab[3] = in_8(sccc);
135 } else if (of_machine_is_compatible("RackMac1,1")
136 || of_machine_is_compatible("RackMac1,2")
137 || of_machine_is_compatible("MacRISC4")) {
138 /* Xserves and G5s default to 57600 */
139 scc_inittab[1] = 0;
140 scc_inittab[3] = 0;
141 } else {
142 /* Others default to 38400 */
143 scc_inittab[1] = 0;
144 scc_inittab[3] = 1;
145 }
146
147 for (i = 0; i < sizeof(scc_inittab); ++i)
148 out_8(sccc, scc_inittab[i]);
149
150
151 udbg_putc = udbg_scc_putc;
152 udbg_getc = udbg_scc_getc;
153 udbg_getc_poll = udbg_scc_getc_poll;
154
155 udbg_puts("Hello World !\n");
156
157 bail:
158 of_node_put(macio);
159 of_node_put(escc);
160 of_node_put(stdout);
161 of_node_put(ch_def);
162 of_node_put(ch_a);
163 }
164
165 #ifdef CONFIG_PPC64
udbg_real_scc_putc(char c)166 static void udbg_real_scc_putc(char c)
167 {
168 while ((real_readb(sccc) & SCC_TXRDY) == 0)
169 ;
170 real_writeb(c, sccd);
171 if (c == '\n')
172 udbg_real_scc_putc('\r');
173 }
174
udbg_init_pmac_realmode(void)175 void __init udbg_init_pmac_realmode(void)
176 {
177 sccc = (volatile u8 __iomem *)0x80013020ul;
178 sccd = (volatile u8 __iomem *)0x80013030ul;
179
180 udbg_putc = udbg_real_scc_putc;
181 udbg_getc = NULL;
182 udbg_getc_poll = NULL;
183 }
184 #endif /* CONFIG_PPC64 */
185
