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 "vl.h"
  26
  27 typedef enum
  28 {
  29     none = 0,
  30     readmode,
  31     writemode,
  32 } nvram_open_mode;
  33
  34 struct ds1225y_t
  35 {
  36     target_phys_addr_t mem_base;
  37     uint32_t capacity;
  38     const char *filename;
  39     QEMUFile *file;
  40     nvram_open_mode open_mode;
  41 };
  42
  43 static int ds1225y_set_to_mode(ds1225y_t *NVRAM, nvram_open_mode mode, const char *filemode)
  44 {
  45     if (NVRAM->open_mode != mode)
  46     {
  47         if (NVRAM->file)
  48             qemu_fclose(NVRAM->file);
  49         NVRAM->file = qemu_fopen(NVRAM->filename, filemode);
  50         NVRAM->open_mode = mode;
  51     }
  52     return (NVRAM->file != NULL);
  53 }
  54
  55 static uint32_t nvram_readb (void *opaque, target_phys_addr_t addr)
  56 {
  57     ds1225y_t *NVRAM = opaque;
  58     int64_t pos;
  59
  60     pos = addr - NVRAM->mem_base;
  61     if (addr >= NVRAM->capacity)
  62         addr -= NVRAM->capacity;
  63
  64     if (!ds1225y_set_to_mode(NVRAM, readmode, "rb"))
  65         return 0;
  66     qemu_fseek(NVRAM->file, pos, SEEK_SET);
  67     return (uint32_t)qemu_get_byte(NVRAM->file);
  68 }
  69
  70 static void nvram_writeb (void *opaque, target_phys_addr_t addr, uint32_t value)
  71 {
  72     ds1225y_t *NVRAM = opaque;
  73     int64_t pos;
  74
  75     pos = addr - NVRAM->mem_base;
  76     if (ds1225y_set_to_mode(NVRAM, writemode, "wb"))
  77     {
  78         qemu_fseek(NVRAM->file, pos, SEEK_SET);
  79         qemu_put_byte(NVRAM->file, (int)value);
  80     }
  81 }
  82
  83 static CPUReadMemoryFunc *nvram_read[] = {
  84     &nvram_readb,
  85     NULL,
  86     NULL,
  87 };
  88
  89 static CPUWriteMemoryFunc *nvram_write[] = {
  90     &nvram_writeb,
  91     NULL,
  92     NULL,
  93 };
  94
  95 static CPUWriteMemoryFunc *nvram_none[] = {
  96     NULL,
  97     NULL,
  98     NULL,
  99 };
 100
 101 /* Initialisation routine */
 102 ds1225y_t *ds1225y_init(target_phys_addr_t mem_base, const char *filename)
 103 {
 104     ds1225y_t *s;
 105     int mem_index1, mem_index2;
 106
 107     s = qemu_mallocz(sizeof(ds1225y_t));
 108     if (!s)
 109         return NULL;
 110     s->mem_base = mem_base;
 111     s->capacity = 0x2000; /* Fixed for ds1225y chip: 8K */
 112     s->filename = filename;
 113
 114     /* Read/write memory */
 115     mem_index1 = cpu_register_io_memory(0, nvram_read, nvram_write, s);
 116     cpu_register_physical_memory(mem_base, s->capacity, mem_index1);
 117     /* Read-only memory */
 118     mem_index2 = cpu_register_io_memory(0, nvram_read, nvram_none, s);
 119     cpu_register_physical_memory(mem_base + s->capacity, s->capacity, mem_index2);
 120     return s;
 121 }