1 /* 2 * arch/powerpc/platforms/embedded6xx/usbgecko_udbg.c 3 * 4 * udbg serial input/output routines for the USB Gecko adapter. 5 * Copyright (C) 2008-2009 The GameCube Linux Team 6 * Copyright (C) 2008,2009 Albert Herranz 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License 10 * as published by the Free Software Foundation; either version 2 11 * of the License, or (at your option) any later version. 12 * 13 */ 14 15 #include <mm/mmu_decl.h> 16 17 #include <asm/io.h> 18 #include <asm/prom.h> 19 #include <asm/udbg.h> 20 #include <asm/fixmap.h> 21 22 #include "usbgecko_udbg.h" 23 24 25 #define EXI_CLK_32MHZ 5 26 27 #define EXI_CSR 0x00 28 #define EXI_CSR_CLKMASK (0x7<<4) 29 #define EXI_CSR_CLK_32MHZ (EXI_CLK_32MHZ<<4) 30 #define EXI_CSR_CSMASK (0x7<<7) 31 #define EXI_CSR_CS_0 (0x1<<7) /* Chip Select 001 */ 32 33 #define EXI_CR 0x0c 34 #define EXI_CR_TSTART (1<<0) 35 #define EXI_CR_WRITE (1<<2) 36 #define EXI_CR_READ_WRITE (2<<2) 37 #define EXI_CR_TLEN(len) (((len)-1)<<4) 38 39 #define EXI_DATA 0x10 40 41 #define UG_READ_ATTEMPTS 100 42 #define UG_WRITE_ATTEMPTS 100 43 44 45 static void __iomem *ug_io_base; 46 47 /* 48 * Performs one input/output transaction between the exi host and the usbgecko. 49 */ 50 static u32 ug_io_transaction(u32 in) 51 { 52 u32 __iomem *csr_reg = ug_io_base + EXI_CSR; 53 u32 __iomem *data_reg = ug_io_base + EXI_DATA; 54 u32 __iomem *cr_reg = ug_io_base + EXI_CR; 55 u32 csr, data, cr; 56 57 /* select */ 58 csr = EXI_CSR_CLK_32MHZ | EXI_CSR_CS_0; 59 out_be32(csr_reg, csr); 60 61 /* read/write */ 62 data = in; 63 out_be32(data_reg, data); 64 cr = EXI_CR_TLEN(2) | EXI_CR_READ_WRITE | EXI_CR_TSTART; 65 out_be32(cr_reg, cr); 66 67 while (in_be32(cr_reg) & EXI_CR_TSTART) 68 barrier(); 69 70 /* deselect */ 71 out_be32(csr_reg, 0); 72 73 /* result */ 74 data = in_be32(data_reg); 75 76 return data; 77 } 78 79 /* 80 * Returns true if an usbgecko adapter is found. 81 */ 82 static int ug_is_adapter_present(void) 83 { 84 if (!ug_io_base) 85 return 0; 86 87 return ug_io_transaction(0x90000000) == 0x04700000; 88 } 89 90 /* 91 * Returns true if the TX fifo is ready for transmission. 92 */ 93 static int ug_is_txfifo_ready(void) 94 { 95 return ug_io_transaction(0xc0000000) & 0x04000000; 96 } 97 98 /* 99 * Tries to transmit a character. 100 * If the TX fifo is not ready the result is undefined. 101 */ 102 static void ug_raw_putc(char ch) 103 { 104 ug_io_transaction(0xb0000000 | (ch << 20)); 105 } 106 107 /* 108 * Transmits a character. 109 * It silently fails if the TX fifo is not ready after a number of retries. 110 */ 111 static void ug_putc(char ch) 112 { 113 int count = UG_WRITE_ATTEMPTS; 114 115 if (!ug_io_base) 116 return; 117 118 if (ch == '\n') 119 ug_putc('\r'); 120 121 while (!ug_is_txfifo_ready() && count--) 122 barrier(); 123 if (count >= 0) 124 ug_raw_putc(ch); 125 } 126 127 /* 128 * Returns true if the RX fifo is ready for transmission. 129 */ 130 static int ug_is_rxfifo_ready(void) 131 { 132 return ug_io_transaction(0xd0000000) & 0x04000000; 133 } 134 135 /* 136 * Tries to receive a character. 137 * If a character is unavailable the function returns -1. 138 */ 139 static int ug_raw_getc(void) 140 { 141 u32 data = ug_io_transaction(0xa0000000); 142 if (data & 0x08000000) 143 return (data >> 16) & 0xff; 144 else 145 return -1; 146 } 147 148 /* 149 * Receives a character. 150 * It fails if the RX fifo is not ready after a number of retries. 151 */ 152 static int ug_getc(void) 153 { 154 int count = UG_READ_ATTEMPTS; 155 156 if (!ug_io_base) 157 return -1; 158 159 while (!ug_is_rxfifo_ready() && count--) 160 barrier(); 161 return ug_raw_getc(); 162 } 163 164 /* 165 * udbg functions. 166 * 167 */ 168 169 /* 170 * Transmits a character. 171 */ 172 void ug_udbg_putc(char ch) 173 { 174 ug_putc(ch); 175 } 176 177 /* 178 * Receives a character. Waits until a character is available. 179 */ 180 static int ug_udbg_getc(void) 181 { 182 int ch; 183 184 while ((ch = ug_getc()) == -1) 185 barrier(); 186 return ch; 187 } 188 189 /* 190 * Receives a character. If a character is not available, returns -1. 191 */ 192 static int ug_udbg_getc_poll(void) 193 { 194 if (!ug_is_rxfifo_ready()) 195 return -1; 196 return ug_getc(); 197 } 198 199 /* 200 * Retrieves and prepares the virtual address needed to access the hardware. 201 */ 202 static void __iomem *ug_udbg_setup_exi_io_base(struct device_node *np) 203 { 204 void __iomem *exi_io_base = NULL; 205 phys_addr_t paddr; 206 const unsigned int *reg; 207 208 reg = of_get_property(np, "reg", NULL); 209 if (reg) { 210 paddr = of_translate_address(np, reg); 211 if (paddr) 212 exi_io_base = ioremap(paddr, reg[1]); 213 } 214 return exi_io_base; 215 } 216 217 /* 218 * Checks if a USB Gecko adapter is inserted in any memory card slot. 219 */ 220 static void __iomem *ug_udbg_probe(void __iomem *exi_io_base) 221 { 222 int i; 223 224 /* look for a usbgecko on memcard slots A and B */ 225 for (i = 0; i < 2; i++) { 226 ug_io_base = exi_io_base + 0x14 * i; 227 if (ug_is_adapter_present()) 228 break; 229 } 230 if (i == 2) 231 ug_io_base = NULL; 232 return ug_io_base; 233 234 } 235 236 /* 237 * USB Gecko udbg support initialization. 238 */ 239 void __init ug_udbg_init(void) 240 { 241 struct device_node *np; 242 void __iomem *exi_io_base; 243 244 if (ug_io_base) 245 udbg_printf("%s: early -> final\n", __func__); 246 247 np = of_find_compatible_node(NULL, NULL, "nintendo,flipper-exi"); 248 if (!np) { 249 udbg_printf("%s: EXI node not found\n", __func__); 250 goto out; 251 } 252 253 exi_io_base = ug_udbg_setup_exi_io_base(np); 254 if (!exi_io_base) { 255 udbg_printf("%s: failed to setup EXI io base\n", __func__); 256 goto done; 257 } 258 259 if (!ug_udbg_probe(exi_io_base)) { 260 udbg_printf("usbgecko_udbg: not found\n"); 261 iounmap(exi_io_base); 262 } else { 263 udbg_putc = ug_udbg_putc; 264 udbg_getc = ug_udbg_getc; 265 udbg_getc_poll = ug_udbg_getc_poll; 266 udbg_printf("usbgecko_udbg: ready\n"); 267 } 268 269 done: 270 of_node_put(np); 271 out: 272 return; 273 } 274 275 #ifdef CONFIG_PPC_EARLY_DEBUG_USBGECKO 276 277 static phys_addr_t __init ug_early_grab_io_addr(void) 278 { 279 #if defined(CONFIG_GAMECUBE) 280 return 0x0c000000; 281 #elif defined(CONFIG_WII) 282 return 0x0d000000; 283 #else 284 #error Invalid platform for USB Gecko based early debugging. 285 #endif 286 } 287 288 /* 289 * USB Gecko early debug support initialization for udbg. 290 */ 291 void __init udbg_init_usbgecko(void) 292 { 293 void __iomem *early_debug_area; 294 void __iomem *exi_io_base; 295 296 /* 297 * At this point we have a BAT already setup that enables I/O 298 * to the EXI hardware. 299 * 300 * The BAT uses a virtual address range reserved at the fixmap. 301 * This must match the virtual address configured in 302 * head_32.S:setup_usbgecko_bat(). 303 */ 304 early_debug_area = (void __iomem *)__fix_to_virt(FIX_EARLY_DEBUG_BASE); 305 exi_io_base = early_debug_area + 0x00006800; 306 307 /* try to detect a USB Gecko */ 308 if (!ug_udbg_probe(exi_io_base)) 309 return; 310 311 /* we found a USB Gecko, load udbg hooks */ 312 udbg_putc = ug_udbg_putc; 313 udbg_getc = ug_udbg_getc; 314 udbg_getc_poll = ug_udbg_getc_poll; 315 316 /* 317 * Prepare again the same BAT for MMU_init. 318 * This allows udbg I/O to continue working after the MMU is 319 * turned on for real. 320 * It is safe to continue using the same virtual address as it is 321 * a reserved fixmap area. 322 */ 323 setbat(1, (unsigned long)early_debug_area, 324 ug_early_grab_io_addr(), 128*1024, PAGE_KERNEL_NCG); 325 } 326 327 #endif /* CONFIG_PPC_EARLY_DEBUG_USBGECKO */ 328 329