arch/powerpc/boot/ugecon.c

   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 */
  35 static void *ug_io_base;
  36
  37
  38 static 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
  65 static int ug_is_txfifo_ready(void)
  66 {
  67         return ug_io_transaction(0xc0000000) & 0x04000000;
  68 }
  69
  70 static void ug_raw_putc(char ch)
  71 {
  72         ug_io_transaction(0xb0000000 | (ch << 20));
  73 }
  74
  75 static 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
  88 void 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
  99 static int ug_is_adapter_present(void)
 100 {
 101         if (!ug_io_base)
 102                 return 0;
 103         return ug_io_transaction(0x90000000) == 0x04700000;
 104 }
 105
 106 static 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
 119 err_out:
 120         return NULL;
 121 }
 122
 123 void *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