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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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 271 272 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 */ 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