loader/usbgecko.c

   1 // Copyright 2008-2009  Segher Boessenkool  <segher@kernel.crashing.org>
   2 // This code is licensed to you under the terms of the GNU GPL, version 2;
   3 // see file COPYING or http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt
   4
   5 // Based on code:
   6 //      Copyright (c) 2008 - Nuke - <wiinuke@gmail.com>
   7
   8 #include "loader.h"
   9
  10
  11 static void exi_write(u32 addr, u32 x)
  12 {
  13         write32(0x0d006800 + addr, x);
  14 }
  15
  16 static u32 exi_read(u32 addr)
  17 {
  18         return read32(0x0d006800 + addr);
  19 }
  20
  21 #define EXI_CH1_STATUS  0x14
  22 #define EXI_CH1_CONTROL 0x20
  23 #define EXI_CH1_DATA    0x24
  24
  25
  26 static void usbgecko_deselect_device(void)
  27 {
  28         exi_write(EXI_CH1_STATUS, 0);
  29 }
  30
  31 static void usbgecko_select_device(void)
  32 {
  33         // device 0, 16MHz
  34         exi_write(EXI_CH1_STATUS, 0xc0);
  35 }
  36
  37 static void usbgecko_wait_for_transfer_complete(void)
  38 {
  39         while (exi_read(EXI_CH1_CONTROL) & 1)
  40                 ;
  41 }
  42
  43
  44 u8 usbgecko_flash_read8(u32 offset)
  45 {
  46         u8 x;
  47
  48         usbgecko_deselect_device();
  49
  50         usbgecko_select_device();
  51         exi_write(EXI_CH1_DATA, 0xf0000000 | (offset << 9));
  52         exi_write(EXI_CH1_CONTROL, 0x35); // 4 bytes immediate write
  53         usbgecko_wait_for_transfer_complete();
  54
  55         usbgecko_select_device();
  56         exi_write(EXI_CH1_CONTROL, 0x39); // 4 bytes immediate read/write
  57         usbgecko_wait_for_transfer_complete();
  58
  59         x = exi_read(EXI_CH1_DATA) >> 23;
  60
  61         usbgecko_deselect_device();
  62
  63         return x;
  64 }
  65
  66 u32 usbgecko_flash_read32(u32 offset)
  67 {
  68         u32 x, i;
  69
  70         x = 0;
  71         for (i = 0; i < 4; i++)
  72                 x = (x << 8) | usbgecko_flash_read8(offset++);
  73
  74         return x;
  75 }
  76
  77
  78
  79 static int usbgecko_console_enabled = 0;
  80
  81 static u32 usbgecko_command(u32 command)
  82 {
  83         u32 x;
  84
  85         usbgecko_select_device();
  86         exi_write(EXI_CH1_DATA, command);
  87         exi_write(EXI_CH1_CONTROL, 0x19); // 2 bytes immediate read/write
  88         usbgecko_wait_for_transfer_complete();
  89
  90         x = exi_read(EXI_CH1_DATA);
  91
  92         usbgecko_deselect_device();
  93
  94         return x;
  95 }
  96
  97 int usbgecko_checkgecko(void)
  98 {
  99         return usbgecko_command(0x90000000) == 0x04700000;
 100 }
 101
 102 void usbgecko_console_putc(u8 c)
 103 {
 104         u32 x;
 105
 106         if (!usbgecko_console_enabled)
 107                 return;
 108
 109         if (c == '\n')
 110                 usbgecko_console_putc('\r');
 111
 112         x = usbgecko_command(0xb0000000 | (c << 20));
 113 }
 114
 115 static void usbgecko_flush(void)
 116 {
 117         u32 x;
 118
 119         do {
 120                 x = usbgecko_command(0xa0000000);
 121         } while (x & 0x08000000);
 122 }
 123
 124 void usbgecko_init(void)
 125 {
 126         if (!usbgecko_checkgecko())
 127                 return;
 128
 129         usbgecko_console_enabled = 1;
 130         usbgecko_flush();
 131 }