1 /*
2 * Copyright 2008-2011, IBM Corporation
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 */
9
10 #include <linux/kernel.h>
11 #include <linux/of.h>
12 #include <linux/io.h>
13
14 #include "wsp.h"
15
16 /*
17 * The UART connection to the H8 is over ttyS1 which is just a 16550.
18 * We assume that FW has it setup right and no one messes with it.
19 */
20
21
22 static u8 __iomem *h8;
23
24 #define RBR 0 /* Receiver Buffer Register */
25 #define THR 0 /* Transmitter Holding Register */
26 #define LSR 5 /* Line Status Register */
27 #define LSR_DR 0x01 /* LSR value for Data-Ready */
28 #define LSR_THRE 0x20 /* LSR value for Transmitter-Holding-Register-Empty */
wsp_h8_putc(int c)29 static void wsp_h8_putc(int c)
30 {
31 u8 lsr;
32
33 do {
34 lsr = readb(h8 + LSR);
35 } while ((lsr & LSR_THRE) != LSR_THRE);
36 writeb(c, h8 + THR);
37 }
38
wsp_h8_getc(void)39 static int wsp_h8_getc(void)
40 {
41 u8 lsr;
42
43 do {
44 lsr = readb(h8 + LSR);
45 } while ((lsr & LSR_DR) != LSR_DR);
46
47 return readb(h8 + RBR);
48 }
49
wsp_h8_puts(const char * s,int sz)50 static void wsp_h8_puts(const char *s, int sz)
51 {
52 int i;
53
54 for (i = 0; i < sz; i++) {
55 wsp_h8_putc(s[i]);
56
57 /* no flow control so wait for echo */
58 wsp_h8_getc();
59 }
60 wsp_h8_putc('\r');
61 wsp_h8_putc('\n');
62 }
63
wsp_h8_terminal_cmd(const char * cmd,int sz)64 static void wsp_h8_terminal_cmd(const char *cmd, int sz)
65 {
66 hard_irq_disable();
67 wsp_h8_puts(cmd, sz);
68 /* should never return, but just in case */
69 for (;;)
70 continue;
71 }
72
73
wsp_h8_restart(char * cmd)74 void wsp_h8_restart(char *cmd)
75 {
76 static const char restart[] = "warm-reset";
77
78 (void)cmd;
79 wsp_h8_terminal_cmd(restart, sizeof(restart) - 1);
80 }
81
wsp_h8_power_off(void)82 void wsp_h8_power_off(void)
83 {
84 static const char off[] = "power-off";
85
86 wsp_h8_terminal_cmd(off, sizeof(off) - 1);
87 }
88
wsp_h8_getaddr(void)89 static void __iomem *wsp_h8_getaddr(void)
90 {
91 struct device_node *aliases;
92 struct device_node *uart;
93 struct property *path;
94 void __iomem *va = NULL;
95
96 /*
97 * there is nothing in the devtree to tell us which is mapped
98 * to the H8, but se know it is the second serial port.
99 */
100
101 aliases = of_find_node_by_path("/aliases");
102 if (aliases == NULL)
103 return NULL;
104
105 path = of_find_property(aliases, "serial1", NULL);
106 if (path == NULL)
107 goto out;
108
109 uart = of_find_node_by_path(path->value);
110 if (uart == NULL)
111 goto out;
112
113 va = of_iomap(uart, 0);
114
115 /* remove it so no one messes with it */
116 of_detach_node(uart);
117 of_node_put(uart);
118
119 out:
120 of_node_put(aliases);
121
122 return va;
123 }
124
wsp_setup_h8(void)125 void __init wsp_setup_h8(void)
126 {
127 h8 = wsp_h8_getaddr();
128
129 /* Devtree change? lets hard map it anyway */
130 if (h8 == NULL) {
131 pr_warn("UART to H8 could not be found");
132 h8 = ioremap(0xffc0008000ULL, 0x100);
133 }
134 }
135