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 }
98
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