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powerpc/powernv: Basic support for OPAL
[mirror_ubuntu-eoan-kernel.git] / arch / powerpc / platforms / powernv / opal.c
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1/*
2 * PowerNV OPAL high level interfaces
3 *
4 * Copyright 2011 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
12#undef DEBUG
13
14#include <linux/types.h>
15#include <linux/of.h>
16#include <linux/of_platform.h>
17#include <asm/opal.h>
18#include <asm/firmware.h>
19
20#include "powernv.h"
21
22struct opal {
23 u64 base;
24 u64 entry;
25} opal;
26
27static struct device_node *opal_node;
28static DEFINE_SPINLOCK(opal_write_lock);
29
30int __init early_init_dt_scan_opal(unsigned long node,
31 const char *uname, int depth, void *data)
32{
33 const void *basep, *entryp;
34 unsigned long basesz, entrysz;
35
36 if (depth != 1 || strcmp(uname, "ibm,opal") != 0)
37 return 0;
38
39 basep = of_get_flat_dt_prop(node, "opal-base-address", &basesz);
40 entryp = of_get_flat_dt_prop(node, "opal-entry-address", &entrysz);
41
42 if (!basep || !entryp)
43 return 1;
44
45 opal.base = of_read_number(basep, basesz/4);
46 opal.entry = of_read_number(entryp, entrysz/4);
47
48 pr_debug("OPAL Base = 0x%llx (basep=%p basesz=%ld)\n",
49 opal.base, basep, basesz);
50 pr_debug("OPAL Entry = 0x%llx (entryp=%p basesz=%ld)\n",
51 opal.entry, entryp, entrysz);
52
53 powerpc_firmware_features |= FW_FEATURE_OPAL;
54 if (of_flat_dt_is_compatible(node, "ibm,opal-v2")) {
55 powerpc_firmware_features |= FW_FEATURE_OPALv2;
56 printk("OPAL V2 detected !\n");
57 } else {
58 printk("OPAL V1 detected !\n");
59 }
60
61 return 1;
62}
63
64int opal_get_chars(uint32_t vtermno, char *buf, int count)
65{
66 s64 len, rc;
67 u64 evt;
68
69 if (!opal.entry)
70 return 0;
71 opal_poll_events(&evt);
72 if ((evt & OPAL_EVENT_CONSOLE_INPUT) == 0)
73 return 0;
74 len = count;
75 rc = opal_console_read(vtermno, &len, buf);
76 if (rc == OPAL_SUCCESS)
77 return len;
78 return 0;
79}
80
81int opal_put_chars(uint32_t vtermno, const char *data, int total_len)
82{
83 int written = 0;
84 s64 len, rc = OPAL_BUSY;
85 unsigned long flags;
86 u64 evt;
87
88 if (!opal.entry)
89 return 0;
90
91 /* We want put_chars to be atomic to avoid mangling of hvsi
92 * packets. To do that, we first test for room and return
93 * -EAGAIN if there isn't enough
94 */
95 spin_lock_irqsave(&opal_write_lock, flags);
96 rc = opal_console_write_buffer_space(vtermno, &len);
97 if (rc || len < total_len) {
98 spin_unlock_irqrestore(&opal_write_lock, flags);
99 /* Closed -> drop characters */
100 if (rc)
101 return total_len;
102 opal_poll_events(&evt);
103 return -EAGAIN;
104 }
105
106 /* We still try to handle partial completions, though they
107 * should no longer happen.
108 */
109 while(total_len > 0 && (rc == OPAL_BUSY ||
110 rc == OPAL_BUSY_EVENT || rc == OPAL_SUCCESS)) {
111 len = total_len;
112 rc = opal_console_write(vtermno, &len, data);
113 if (rc == OPAL_SUCCESS) {
114 total_len -= len;
115 data += len;
116 written += len;
117 }
118 /* This is a bit nasty but we need that for the console to
119 * flush when there aren't any interrupts. We will clean
120 * things a bit later to limit that to synchronous path
121 * such as the kernel console and xmon/udbg
122 */
123 do
124 opal_poll_events(&evt);
125 while(rc == OPAL_SUCCESS && (evt & OPAL_EVENT_CONSOLE_OUTPUT));
126 }
127 spin_unlock_irqrestore(&opal_write_lock, flags);
128 return written;
129}
130
131static int __init opal_init(void)
132{
133 struct device_node *np, *consoles;
134
135 opal_node = of_find_node_by_path("/ibm,opal");
136 if (!opal_node) {
137 pr_warn("opal: Node not found\n");
138 return -ENODEV;
139 }
140 if (firmware_has_feature(FW_FEATURE_OPALv2))
141 consoles = of_find_node_by_path("/ibm,opal/consoles");
142 else
143 consoles = of_node_get(opal_node);
144
145 /* Register serial ports */
146 for_each_child_of_node(consoles, np) {
147 if (strcmp(np->name, "serial"))
148 continue;
149 of_platform_device_create(np, NULL, NULL);
150 }
151 of_node_put(consoles);
152 return 0;
153}
154subsys_initcall(opal_init);