treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
[muen/linux.git] / arch / powerpc / boot / opal.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (c) 2016 IBM Corporation.
4  */
5
6 #include "ops.h"
7 #include "stdio.h"
8 #include "io.h"
9 #include <libfdt.h>
10 #include "../include/asm/opal-api.h"
11
12 /* Global OPAL struct used by opal-call.S */
13 struct opal {
14         u64 base;
15         u64 entry;
16 } opal;
17
18 static u32 opal_con_id;
19
20 /* see opal-wrappers.S */
21 int64_t opal_console_write(int64_t term_number, u64 *length, const u8 *buffer);
22 int64_t opal_console_read(int64_t term_number, uint64_t *length, u8 *buffer);
23 int64_t opal_console_write_buffer_space(uint64_t term_number, uint64_t *length);
24 int64_t opal_console_flush(uint64_t term_number);
25 int64_t opal_poll_events(uint64_t *outstanding_event_mask);
26
27 void opal_kentry(unsigned long fdt_addr, void *vmlinux_addr);
28
29 static int opal_con_open(void)
30 {
31         /*
32          * When OPAL loads the boot kernel it stashes the OPAL base and entry
33          * address in r8 and r9 so the kernel can use the OPAL console
34          * before unflattening the devicetree. While executing the wrapper will
35          * probably trash r8 and r9 so this kentry hook restores them before
36          * entering the decompressed kernel.
37          */
38         platform_ops.kentry = opal_kentry;
39         return 0;
40 }
41
42 static void opal_con_putc(unsigned char c)
43 {
44         int64_t rc;
45         uint64_t olen, len;
46
47         do {
48                 rc = opal_console_write_buffer_space(opal_con_id, &olen);
49                 len = be64_to_cpu(olen);
50                 if (rc)
51                         return;
52                 opal_poll_events(NULL);
53         } while (len < 1);
54
55
56         olen = cpu_to_be64(1);
57         opal_console_write(opal_con_id, &olen, &c);
58 }
59
60 static void opal_con_close(void)
61 {
62         opal_console_flush(opal_con_id);
63 }
64
65 static void opal_init(void)
66 {
67         void *opal_node;
68
69         opal_node = finddevice("/ibm,opal");
70         if (!opal_node)
71                 return;
72         if (getprop(opal_node, "opal-base-address", &opal.base, sizeof(u64)) < 0)
73                 return;
74         opal.base = be64_to_cpu(opal.base);
75         if (getprop(opal_node, "opal-entry-address", &opal.entry, sizeof(u64)) < 0)
76                 return;
77         opal.entry = be64_to_cpu(opal.entry);
78 }
79
80 int opal_console_init(void *devp, struct serial_console_data *scdp)
81 {
82         opal_init();
83
84         if (devp) {
85                 int n = getprop(devp, "reg", &opal_con_id, sizeof(u32));
86                 if (n != sizeof(u32))
87                         return -1;
88                 opal_con_id = be32_to_cpu(opal_con_id);
89         } else
90                 opal_con_id = 0;
91
92         scdp->open = opal_con_open;
93         scdp->putc = opal_con_putc;
94         scdp->close = opal_con_close;
95
96         return 0;
97 }