1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * arch/powerpc/boot/ugecon.c
4 *
5 * USB Gecko bootwrapper console.
6 * Copyright (C) 2008-2009 The GameCube Linux Team
7 * Copyright (C) 2008,2009 Albert Herranz
8 */
9
10#include <stddef.h>
11#include "stdio.h"
12#include "types.h"
13#include "io.h"
14#include "ops.h"
15
16
17#define EXI_CLK_32MHZ           5
18
19#define EXI_CSR                 0x00
20#define   EXI_CSR_CLKMASK       (0x7<<4)
21#define     EXI_CSR_CLK_32MHZ   (EXI_CLK_32MHZ<<4)
22#define   EXI_CSR_CSMASK        (0x7<<7)
23#define     EXI_CSR_CS_0        (0x1<<7)  /* Chip Select 001 */
24
25#define EXI_CR                  0x0c
26#define   EXI_CR_TSTART         (1<<0)
27#define   EXI_CR_WRITE		(1<<2)
28#define   EXI_CR_READ_WRITE     (2<<2)
29#define   EXI_CR_TLEN(len)      (((len)-1)<<4)
30
31#define EXI_DATA                0x10
32
33
34/* virtual address base for input/output, retrieved from device tree */
35static void *ug_io_base;
36
37
38static u32 ug_io_transaction(u32 in)
39{
40	u32 *csr_reg = ug_io_base + EXI_CSR;
41	u32 *data_reg = ug_io_base + EXI_DATA;
42	u32 *cr_reg = ug_io_base + EXI_CR;
43	u32 csr, data, cr;
44
45	/* select */
46	csr = EXI_CSR_CLK_32MHZ | EXI_CSR_CS_0;
47	out_be32(csr_reg, csr);
48
49	/* read/write */
50	data = in;
51	out_be32(data_reg, data);
52	cr = EXI_CR_TLEN(2) | EXI_CR_READ_WRITE | EXI_CR_TSTART;
53	out_be32(cr_reg, cr);
54
55	while (in_be32(cr_reg) & EXI_CR_TSTART)
56		barrier();
57
58	/* deselect */
59	out_be32(csr_reg, 0);
60
61	data = in_be32(data_reg);
62	return data;
63}
64
65static int ug_is_txfifo_ready(void)
66{
67	return ug_io_transaction(0xc0000000) & 0x04000000;
68}
69
70static void ug_raw_putc(char ch)
71{
72	ug_io_transaction(0xb0000000 | (ch << 20));
73}
74
75static void ug_putc(char ch)
76{
77	int count = 16;
78
79	if (!ug_io_base)
80		return;
81
82	while (!ug_is_txfifo_ready() && count--)
83		barrier();
84	if (count >= 0)
85		ug_raw_putc(ch);
86}
87
88void ug_console_write(const char *buf, int len)
89{
90	char *b = (char *)buf;
91
92	while (len--) {
93		if (*b == '\n')
94			ug_putc('\r');
95		ug_putc(*b++);
96	}
97}
98
99static int ug_is_adapter_present(void)
100{
101	if (!ug_io_base)
102		return 0;
103	return ug_io_transaction(0x90000000) == 0x04700000;
104}
105
106static void *ug_grab_exi_io_base(void)
107{
108	u32 v;
109	void *devp;
110
111	devp = find_node_by_compatible(NULL, "nintendo,flipper-exi");
112	if (devp == NULL)
113		goto err_out;
114	if (getprop(devp, "virtual-reg", &v, sizeof(v)) != sizeof(v))
115		goto err_out;
116
117	return (void *)v;
118
119err_out:
120	return NULL;
121}
122
123void *ug_probe(void)
124{
125	void *exi_io_base;
126	int i;
127
128	exi_io_base = ug_grab_exi_io_base();
129	if (!exi_io_base)
130		return NULL;
131
132	/* look for a usbgecko on memcard slots A and B */
133	for (i = 0; i < 2; i++) {
134		ug_io_base = exi_io_base + 0x14 * i;
135		if (ug_is_adapter_present())
136			break;
137	}
138	if (i == 2)
139		ug_io_base = NULL;
140	return ug_io_base;
141}
142
143