hw/ds1225y.c

   1 /*
   2  * QEMU NVRAM emulation for DS1225Y chip
   3  *
   4  * Copyright (c) 2007 Hervé Poussineau
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24
  25 #include "hw.h"
  26 #include "mips.h"
  27 #include "nvram.h"
  28
  29 typedef enum
  30 {
  31     none = 0,
  32     readmode,
  33     writemode,
  34 } nvram_open_mode;
  35
  36 struct ds1225y_t
  37 {
  38     target_phys_addr_t mem_base;
  39     uint32_t capacity;
  40     const char *filename;
  41     QEMUFile *file;
  42     nvram_open_mode open_mode;
  43 };
  44
  45 static int ds1225y_set_to_mode(ds1225y_t *NVRAM, nvram_open_mode mode, const char *filemode)
  46 {
  47     if (NVRAM->open_mode != mode)
  48     {
  49         if (NVRAM->file)
  50             qemu_fclose(NVRAM->file);
  51         NVRAM->file = qemu_fopen(NVRAM->filename, filemode);
  52         NVRAM->open_mode = mode;
  53     }
  54     return (NVRAM->file != NULL);
  55 }
  56
  57 static uint32_t nvram_readb (void *opaque, target_phys_addr_t addr)
  58 {
  59     ds1225y_t *NVRAM = opaque;
  60     int64_t pos;
  61
  62     pos = addr - NVRAM->mem_base;
  63     if (addr >= NVRAM->capacity)
  64         addr -= NVRAM->capacity;
  65
  66     if (!ds1225y_set_to_mode(NVRAM, readmode, "rb"))
  67         return 0;
  68     qemu_fseek(NVRAM->file, pos, SEEK_SET);
  69     return (uint32_t)qemu_get_byte(NVRAM->file);
  70 }
  71
  72 static void nvram_writeb (void *opaque, target_phys_addr_t addr, uint32_t value)
  73 {
  74     ds1225y_t *NVRAM = opaque;
  75     int64_t pos;
  76
  77     pos = addr - NVRAM->mem_base;
  78     if (ds1225y_set_to_mode(NVRAM, writemode, "wb"))
  79     {
  80         qemu_fseek(NVRAM->file, pos, SEEK_SET);
  81         qemu_put_byte(NVRAM->file, (int)value);
  82     }
  83 }
  84
  85 static CPUReadMemoryFunc *nvram_read[] = {
  86     &nvram_readb,
  87     NULL,
  88     NULL,
  89 };
  90
  91 static CPUWriteMemoryFunc *nvram_write[] = {
  92     &nvram_writeb,
  93     NULL,
  94     NULL,
  95 };
  96
  97 static CPUWriteMemoryFunc *nvram_none[] = {
  98     NULL,
  99     NULL,
 100     NULL,
 101 };
 102
 103 /* Initialisation routine */
 104 ds1225y_t *ds1225y_init(target_phys_addr_t mem_base, const char *filename)
 105 {
 106     ds1225y_t *s;
 107     int mem_index1, mem_index2;
 108
 109     s = qemu_mallocz(sizeof(ds1225y_t));
 110     if (!s)
 111         return NULL;
 112     s->mem_base = mem_base;
 113     s->capacity = 0x2000; /* Fixed for ds1225y chip: 8K */
 114     s->filename = filename;
 115
 116     /* Read/write memory */
 117     mem_index1 = cpu_register_io_memory(0, nvram_read, nvram_write, s);
 118     cpu_register_physical_memory(mem_base, s->capacity, mem_index1);
 119     /* Read-only memory */
 120     mem_index2 = cpu_register_io_memory(0, nvram_read, nvram_none, s);
 121     cpu_register_physical_memory(mem_base + s->capacity, s->capacity, mem_index2);
 122     return s;
 123 }