arch/powerpc/platforms/embedded6xx/usbgecko_udbg.c

   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 done;
 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         if (np)
 271                 of_node_put(np);
 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