GNU Linux-libre 4.14.266-gnu1
[releases.git] / arch / powerpc / boot / opal.c
1 /*
2  * Copyright (c) 2016 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 "ops.h"
11 #include "stdio.h"
12 #include "io.h"
13 #include <libfdt.h>
14 #include "../include/asm/opal-api.h"
15
16 #ifdef CONFIG_PPC64_BOOT_WRAPPER
17
18 /* Global OPAL struct used by opal-call.S */
19 struct opal {
20         u64 base;
21         u64 entry;
22 } opal;
23
24 static u32 opal_con_id;
25
26 /* see opal-wrappers.S */
27 int64_t opal_console_write(int64_t term_number, u64 *length, const u8 *buffer);
28 int64_t opal_console_read(int64_t term_number, uint64_t *length, u8 *buffer);
29 int64_t opal_console_write_buffer_space(uint64_t term_number, uint64_t *length);
30 int64_t opal_console_flush(uint64_t term_number);
31 int64_t opal_poll_events(uint64_t *outstanding_event_mask);
32
33 void opal_kentry(unsigned long fdt_addr, void *vmlinux_addr);
34
35 static int opal_con_open(void)
36 {
37         /*
38          * When OPAL loads the boot kernel it stashes the OPAL base and entry
39          * address in r8 and r9 so the kernel can use the OPAL console
40          * before unflattening the devicetree. While executing the wrapper will
41          * probably trash r8 and r9 so this kentry hook restores them before
42          * entering the decompressed kernel.
43          */
44         platform_ops.kentry = opal_kentry;
45         return 0;
46 }
47
48 static void opal_con_putc(unsigned char c)
49 {
50         int64_t rc;
51         uint64_t olen, len;
52
53         do {
54                 rc = opal_console_write_buffer_space(opal_con_id, &olen);
55                 len = be64_to_cpu(olen);
56                 if (rc)
57                         return;
58                 opal_poll_events(NULL);
59         } while (len < 1);
60
61
62         olen = cpu_to_be64(1);
63         opal_console_write(opal_con_id, &olen, &c);
64 }
65
66 static void opal_con_close(void)
67 {
68         opal_console_flush(opal_con_id);
69 }
70
71 static void opal_init(void)
72 {
73         void *opal_node;
74
75         opal_node = finddevice("/ibm,opal");
76         if (!opal_node)
77                 return;
78         if (getprop(opal_node, "opal-base-address", &opal.base, sizeof(u64)) < 0)
79                 return;
80         opal.base = be64_to_cpu(opal.base);
81         if (getprop(opal_node, "opal-entry-address", &opal.entry, sizeof(u64)) < 0)
82                 return;
83         opal.entry = be64_to_cpu(opal.entry);
84 }
85
86 int opal_console_init(void *devp, struct serial_console_data *scdp)
87 {
88         opal_init();
89
90         if (devp) {
91                 int n = getprop(devp, "reg", &opal_con_id, sizeof(u32));
92                 if (n != sizeof(u32))
93                         return -1;
94                 opal_con_id = be32_to_cpu(opal_con_id);
95         } else
96                 opal_con_id = 0;
97
98         scdp->open = opal_con_open;
99         scdp->putc = opal_con_putc;
100         scdp->close = opal_con_close;
101
102         return 0;
103 }
104 #else
105 int opal_console_init(void *devp, struct serial_console_data *scdp)
106 {
107         return -1;
108 }
109 #endif /* __powerpc64__ */