1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * arch/powerpc/platforms/embedded6xx/usbgecko_udbg.c
4 *
5 * udbg serial input/output routines for the USB Gecko adapter.
6 * Copyright (C) 2008-2009 The GameCube Linux Team
7 * Copyright (C) 2008,2009 Albert Herranz
8 */
9
10 #include <mm/mmu_decl.h>
11
12 #include <asm/io.h>
13 #include <asm/prom.h>
14 #include <asm/udbg.h>
15 #include <asm/fixmap.h>
16
17 #include "usbgecko_udbg.h"
18
19
20 #define EXI_CLK_32MHZ 5
21
22 #define EXI_CSR 0x00
23 #define EXI_CSR_CLKMASK (0x7<<4)
24 #define EXI_CSR_CLK_32MHZ (EXI_CLK_32MHZ<<4)
25 #define EXI_CSR_CSMASK (0x7<<7)
26 #define EXI_CSR_CS_0 (0x1<<7) /* Chip Select 001 */
27
28 #define EXI_CR 0x0c
29 #define EXI_CR_TSTART (1<<0)
30 #define EXI_CR_WRITE (1<<2)
31 #define EXI_CR_READ_WRITE (2<<2)
32 #define EXI_CR_TLEN(len) (((len)-1)<<4)
33
34 #define EXI_DATA 0x10
35
36 #define UG_READ_ATTEMPTS 100
37 #define UG_WRITE_ATTEMPTS 100
38
39
40 static void __iomem *ug_io_base;
41
42 /*
43 * Performs one input/output transaction between the exi host and the usbgecko.
44 */
ug_io_transaction(u32 in)45 static u32 ug_io_transaction(u32 in)
46 {
47 u32 __iomem *csr_reg = ug_io_base + EXI_CSR;
48 u32 __iomem *data_reg = ug_io_base + EXI_DATA;
49 u32 __iomem *cr_reg = ug_io_base + EXI_CR;
50 u32 csr, data, cr;
51
52 /* select */
53 csr = EXI_CSR_CLK_32MHZ | EXI_CSR_CS_0;
54 out_be32(csr_reg, csr);
55
56 /* read/write */
57 data = in;
58 out_be32(data_reg, data);
59 cr = EXI_CR_TLEN(2) | EXI_CR_READ_WRITE | EXI_CR_TSTART;
60 out_be32(cr_reg, cr);
61
62 while (in_be32(cr_reg) & EXI_CR_TSTART)
63 barrier();
64
65 /* deselect */
66 out_be32(csr_reg, 0);
67
68 /* result */
69 data = in_be32(data_reg);
70
71 return data;
72 }
73
74 /*
75 * Returns true if an usbgecko adapter is found.
76 */
ug_is_adapter_present(void)77 static int ug_is_adapter_present(void)
78 {
79 if (!ug_io_base)
80 return 0;
81
82 return ug_io_transaction(0x90000000) == 0x04700000;
83 }
84
85 /*
86 * Returns true if the TX fifo is ready for transmission.
87 */
ug_is_txfifo_ready(void)88 static int ug_is_txfifo_ready(void)
89 {
90 return ug_io_transaction(0xc0000000) & 0x04000000;
91 }
92
93 /*
94 * Tries to transmit a character.
95 * If the TX fifo is not ready the result is undefined.
96 */
ug_raw_putc(char ch)97 static void ug_raw_putc(char ch)
98 {
99 ug_io_transaction(0xb0000000 | (ch << 20));
100 }
101
102 /*
103 * Transmits a character.
104 * It silently fails if the TX fifo is not ready after a number of retries.
105 */
ug_putc(char ch)106 static void ug_putc(char ch)
107 {
108 int count = UG_WRITE_ATTEMPTS;
109
110 if (!ug_io_base)
111 return;
112
113 if (ch == '\n')
114 ug_putc('\r');
115
116 while (!ug_is_txfifo_ready() && count--)
117 barrier();
118 if (count >= 0)
119 ug_raw_putc(ch);
120 }
121
122 /*
123 * Returns true if the RX fifo is ready for transmission.
124 */
ug_is_rxfifo_ready(void)125 static int ug_is_rxfifo_ready(void)
126 {
127 return ug_io_transaction(0xd0000000) & 0x04000000;
128 }
129
130 /*
131 * Tries to receive a character.
132 * If a character is unavailable the function returns -1.
133 */
ug_raw_getc(void)134 static int ug_raw_getc(void)
135 {
136 u32 data = ug_io_transaction(0xa0000000);
137 if (data & 0x08000000)
138 return (data >> 16) & 0xff;
139 else
140 return -1;
141 }
142
143 /*
144 * Receives a character.
145 * It fails if the RX fifo is not ready after a number of retries.
146 */
ug_getc(void)147 static int ug_getc(void)
148 {
149 int count = UG_READ_ATTEMPTS;
150
151 if (!ug_io_base)
152 return -1;
153
154 while (!ug_is_rxfifo_ready() && count--)
155 barrier();
156 return ug_raw_getc();
157 }
158
159 /*
160 * udbg functions.
161 *
162 */
163
164 /*
165 * Transmits a character.
166 */
ug_udbg_putc(char ch)167 static void ug_udbg_putc(char ch)
168 {
169 ug_putc(ch);
170 }
171
172 /*
173 * Receives a character. Waits until a character is available.
174 */
ug_udbg_getc(void)175 static int ug_udbg_getc(void)
176 {
177 int ch;
178
179 while ((ch = ug_getc()) == -1)
180 barrier();
181 return ch;
182 }
183
184 /*
185 * Receives a character. If a character is not available, returns -1.
186 */
ug_udbg_getc_poll(void)187 static int ug_udbg_getc_poll(void)
188 {
189 if (!ug_is_rxfifo_ready())
190 return -1;
191 return ug_getc();
192 }
193
194 /*
195 * Retrieves and prepares the virtual address needed to access the hardware.
196 */
ug_udbg_setup_exi_io_base(struct device_node * np)197 static void __iomem *ug_udbg_setup_exi_io_base(struct device_node *np)
198 {
199 void __iomem *exi_io_base = NULL;
200 phys_addr_t paddr;
201 const unsigned int *reg;
202
203 reg = of_get_property(np, "reg", NULL);
204 if (reg) {
205 paddr = of_translate_address(np, reg);
206 if (paddr)
207 exi_io_base = ioremap(paddr, reg[1]);
208 }
209 return exi_io_base;
210 }
211
212 /*
213 * Checks if a USB Gecko adapter is inserted in any memory card slot.
214 */
ug_udbg_probe(void __iomem * exi_io_base)215 static void __iomem *ug_udbg_probe(void __iomem *exi_io_base)
216 {
217 int i;
218
219 /* look for a usbgecko on memcard slots A and B */
220 for (i = 0; i < 2; i++) {
221 ug_io_base = exi_io_base + 0x14 * i;
222 if (ug_is_adapter_present())
223 break;
224 }
225 if (i == 2)
226 ug_io_base = NULL;
227 return ug_io_base;
228
229 }
230
231 /*
232 * USB Gecko udbg support initialization.
233 */
ug_udbg_init(void)234 void __init ug_udbg_init(void)
235 {
236 struct device_node *np;
237 void __iomem *exi_io_base;
238
239 if (ug_io_base)
240 udbg_printf("%s: early -> final\n", __func__);
241
242 np = of_find_compatible_node(NULL, NULL, "nintendo,flipper-exi");
243 if (!np) {
244 udbg_printf("%s: EXI node not found\n", __func__);
245 goto out;
246 }
247
248 exi_io_base = ug_udbg_setup_exi_io_base(np);
249 if (!exi_io_base) {
250 udbg_printf("%s: failed to setup EXI io base\n", __func__);
251 goto done;
252 }
253
254 if (!ug_udbg_probe(exi_io_base)) {
255 udbg_printf("usbgecko_udbg: not found\n");
256 iounmap(exi_io_base);
257 } else {
258 udbg_putc = ug_udbg_putc;
259 udbg_getc = ug_udbg_getc;
260 udbg_getc_poll = ug_udbg_getc_poll;
261 udbg_printf("usbgecko_udbg: ready\n");
262 }
263
264 done:
265 of_node_put(np);
266 out:
267 return;
268 }
269
270 #ifdef CONFIG_PPC_EARLY_DEBUG_USBGECKO
271
ug_early_grab_io_addr(void)272 static phys_addr_t __init ug_early_grab_io_addr(void)
273 {
274 #if defined(CONFIG_GAMECUBE)
275 return 0x0c000000;
276 #elif defined(CONFIG_WII)
277 return 0x0d000000;
278 #else
279 #error Invalid platform for USB Gecko based early debugging.
280 #endif
281 }
282
283 /*
284 * USB Gecko early debug support initialization for udbg.
285 */
udbg_init_usbgecko(void)286 void __init udbg_init_usbgecko(void)
287 {
288 void __iomem *early_debug_area;
289 void __iomem *exi_io_base;
290
291 /*
292 * At this point we have a BAT already setup that enables I/O
293 * to the EXI hardware.
294 *
295 * The BAT uses a virtual address range reserved at the fixmap.
296 * This must match the virtual address configured in
297 * head_32.S:setup_usbgecko_bat().
298 */
299 early_debug_area = (void __iomem *)__fix_to_virt(FIX_EARLY_DEBUG_BASE);
300 exi_io_base = early_debug_area + 0x00006800;
301
302 /* try to detect a USB Gecko */
303 if (!ug_udbg_probe(exi_io_base))
304 return;
305
306 /* we found a USB Gecko, load udbg hooks */
307 udbg_putc = ug_udbg_putc;
308 udbg_getc = ug_udbg_getc;
309 udbg_getc_poll = ug_udbg_getc_poll;
310
311 /*
312 * Prepare again the same BAT for MMU_init.
313 * This allows udbg I/O to continue working after the MMU is
314 * turned on for real.
315 * It is safe to continue using the same virtual address as it is
316 * a reserved fixmap area.
317 */
318 setbat(1, (unsigned long)early_debug_area,
319 ug_early_grab_io_addr(), 128*1024, PAGE_KERNEL_NCG);
320 }
321
322 #endif /* CONFIG_PPC_EARLY_DEBUG_USBGECKO */
323
324