xref: /openbmc/linux/arch/powerpc/boot/serial.c (revision e01432ba)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Generic serial console support
4  *
5  * Author: Mark A. Greer <mgreer@mvista.com>
6  *
7  * Code in serial_edit_cmdline() copied from <file:arch/ppc/boot/simple/misc.c>
8  * and was written by Matt Porter <mporter@kernel.crashing.org>.
9  *
10  * 2001,2006 (c) MontaVista Software, Inc.
11  */
12 #include <stdarg.h>
13 #include <stddef.h>
14 #include "types.h"
15 #include "string.h"
16 #include "stdio.h"
17 #include "io.h"
18 #include "ops.h"
19 
serial_open(void)20 static int serial_open(void)
21 {
22 	struct serial_console_data *scdp = console_ops.data;
23 	return scdp->open();
24 }
25 
serial_write(const char * buf,int len)26 static void serial_write(const char *buf, int len)
27 {
28 	struct serial_console_data *scdp = console_ops.data;
29 
30 	while (*buf != '\0')
31 		scdp->putc(*buf++);
32 }
33 
serial_edit_cmdline(char * buf,int len,unsigned int timeout)34 static void serial_edit_cmdline(char *buf, int len, unsigned int timeout)
35 {
36 	int timer = 0, count;
37 	char ch, *cp;
38 	struct serial_console_data *scdp = console_ops.data;
39 
40 	cp = buf;
41 	count = strlen(buf);
42 	cp = &buf[count];
43 	count++;
44 
45 	do {
46 		if (scdp->tstc()) {
47 			while (((ch = scdp->getc()) != '\n') && (ch != '\r')) {
48 				/* Test for backspace/delete */
49 				if ((ch == '\b') || (ch == '\177')) {
50 					if (cp != buf) {
51 						cp--;
52 						count--;
53 						printf("\b \b");
54 					}
55 				/* Test for ^x/^u (and wipe the line) */
56 				} else if ((ch == '\030') || (ch == '\025')) {
57 					while (cp != buf) {
58 						cp--;
59 						count--;
60 						printf("\b \b");
61 					}
62 				} else if (count < len) {
63 						*cp++ = ch;
64 						count++;
65 						scdp->putc(ch);
66 				}
67 			}
68 			break;  /* Exit 'timer' loop */
69 		}
70 		udelay(1000);  /* 1 msec */
71 	} while (timer++ < timeout);
72 	*cp = 0;
73 }
74 
serial_close(void)75 static void serial_close(void)
76 {
77 	struct serial_console_data *scdp = console_ops.data;
78 
79 	if (scdp->close)
80 		scdp->close();
81 }
82 
serial_get_stdout_devp(void)83 static void *serial_get_stdout_devp(void)
84 {
85 	void *devp;
86 	char devtype[MAX_PROP_LEN];
87 	char path[MAX_PATH_LEN];
88 
89 	devp = finddevice("/chosen");
90 	if (devp == NULL)
91 		goto err_out;
92 
93 	if (getprop(devp, "linux,stdout-path", path, MAX_PATH_LEN) > 0 ||
94 		getprop(devp, "stdout-path", path, MAX_PATH_LEN) > 0) {
95 		devp = finddevice(path);
96 		if (devp == NULL)
97 			goto err_out;
98 
99 		if ((getprop(devp, "device_type", devtype, sizeof(devtype)) > 0)
100 				&& !strcmp(devtype, "serial"))
101 			return devp;
102 	}
103 err_out:
104 	return NULL;
105 }
106 
107 static struct serial_console_data serial_cd;
108 
109 /* Node's "compatible" property determines which serial driver to use */
serial_console_init(void)110 int serial_console_init(void)
111 {
112 	void *devp;
113 	int rc = -1;
114 
115 	devp = serial_get_stdout_devp();
116 	if (devp == NULL)
117 		goto err_out;
118 
119 	if (dt_is_compatible(devp, "ns16550") ||
120 	    dt_is_compatible(devp, "pnpPNP,501"))
121 		rc = ns16550_console_init(devp, &serial_cd);
122 #ifdef CONFIG_CPM
123 	else if (dt_is_compatible(devp, "fsl,cpm1-scc-uart") ||
124 	         dt_is_compatible(devp, "fsl,cpm1-smc-uart") ||
125 	         dt_is_compatible(devp, "fsl,cpm2-scc-uart") ||
126 	         dt_is_compatible(devp, "fsl,cpm2-smc-uart"))
127 		rc = cpm_console_init(devp, &serial_cd);
128 #endif
129 #ifdef CONFIG_PPC_MPC52xx
130 	else if (dt_is_compatible(devp, "fsl,mpc5200-psc-uart"))
131 		rc = mpc5200_psc_console_init(devp, &serial_cd);
132 #endif
133 #ifdef CONFIG_PPC_POWERNV
134 	else if (dt_is_compatible(devp, "ibm,opal-console-raw"))
135 		rc = opal_console_init(devp, &serial_cd);
136 #endif
137 
138 	/* Add other serial console driver calls here */
139 
140 	if (!rc) {
141 		console_ops.open = serial_open;
142 		console_ops.write = serial_write;
143 		console_ops.close = serial_close;
144 		console_ops.data = &serial_cd;
145 
146 		if (serial_cd.getc)
147 			console_ops.edit_cmdline = serial_edit_cmdline;
148 
149 		return 0;
150 	}
151 err_out:
152 	return -1;
153 }
154