Re: [Qemu-devel] [4/6] ds1225y nvram: Fix some bugs

[Aurelien Jarno <aurelien@aurel32.net>]

On Mon, Mar 03, 2008 at 11:45:28AM +0100, Hervé Poussineau wrote:
> Attached files fixes some problems with nvram emulation:
> - whole nvram was erased in some conditions
> - fix out of range accesses
> - improve speed by keeping contents in memory
>
> Sorry to not provide a patch for ds1225y.c, but it contains mixed  
> line-endings and my diff/patch tools doesn't like that.

I have fixed the line-terminators in the CVS. Please find below the
diff, with inline comments.

> diff --git a/hw/ds1225y.c b/hw/ds1225y.c
> index 2b3f02e..a0c52a8 100644
> --- a/hw/ds1225y.c
> +++ b/hw/ds1225y.c
> @@ -1,8 +1,8 @@
>  /*
>   * QEMU NVRAM emulation for DS1225Y chip
> - * 
> - * Copyright (c) 2007 Hervé Poussineau
> - * 
> + *
> + * Copyright (c) 2007-2008 Hervé Poussineau
> + *
>   * Permission is hereby granted, free of charge, to any person obtaining a copy
>   * of this software and associated documentation files (the "Software"), to deal
>   * in the Software without restriction, including without limitation the rights
> @@ -26,98 +26,167 @@
>  #include "mips.h"
>  #include "nvram.h"
>  
> -typedef enum
> -{
> -    none = 0,
> -    readmode,
> -    writemode,
> -} nvram_open_mode;
> +//#define DEBUG_NVRAM
>  
> -struct ds1225y_t
> +typedef struct ds1225y_t
>  {
>      target_phys_addr_t mem_base;
>      uint32_t capacity;
> -    const char *filename;
>      QEMUFile *file;
> -    nvram_open_mode open_mode;
> -};
> +    uint8_t *contents;
> +    uint8_t protection;
> +} ds1225y_t;
>  
> -static int ds1225y_set_to_mode(ds1225y_t *NVRAM, nvram_open_mode mode, const char *filemode)
> -{
> -    if (NVRAM->open_mode != mode)
> -    {
> -        if (NVRAM->file)
> -            qemu_fclose(NVRAM->file);
> -        NVRAM->file = qemu_fopen(NVRAM->filename, filemode);
> -        NVRAM->open_mode = mode;
> -    }
> -    return (NVRAM->file != NULL);
> -}
>  
>  static uint32_t nvram_readb (void *opaque, target_phys_addr_t addr)
>  {
> -    ds1225y_t *NVRAM = opaque;
> +    ds1225y_t *s = opaque;
>      int64_t pos;
> +    uint32_t val;
> +
> +    pos = addr - s->mem_base;
> +    if (pos >= s->capacity)
> +        pos -= s->capacity;
>  
> -    pos = addr - NVRAM->mem_base;
> -    if (addr >= NVRAM->capacity)
> -        addr -= NVRAM->capacity;
> +    val = s->contents[pos];
>  
> -    if (!ds1225y_set_to_mode(NVRAM, readmode, "rb"))
> -        return 0;
> -    qemu_fseek(NVRAM->file, pos, SEEK_SET);
> -    return (uint32_t)qemu_get_byte(NVRAM->file);
> +#ifdef DEBUG_NVRAM
> +    printf("nvram: read 0x%x at " TARGET_FMT_lx "\n", val, addr);
> +#endif
> +    return val;
> +}
> +
> +static uint32_t nvram_readw (void *opaque, target_phys_addr_t addr)
> +{
> +    uint32_t v;
> +    v = nvram_readb(opaque, addr);
> +    v |= nvram_readb(opaque, addr + 1) << 8;
> +    return v;
>  }
>  
> -static void nvram_writeb (void *opaque, target_phys_addr_t addr, uint32_t value)
> +static uint32_t nvram_readl (void *opaque, target_phys_addr_t addr)
>  {
> -    ds1225y_t *NVRAM = opaque;
> +    uint32_t v;
> +    v = nvram_readb(opaque, addr);
> +    v |= nvram_readb(opaque, addr + 1) << 8;
> +    v |= nvram_readb(opaque, addr + 2) << 16;
> +    v |= nvram_readb(opaque, addr + 3) << 24;
> +    return v;
> +}
> +
> +static void nvram_writeb (void *opaque, target_phys_addr_t addr, uint32_t val)
> +{
> +    ds1225y_t *s = opaque;
>      int64_t pos;
>  
> -    pos = addr - NVRAM->mem_base;
> -    if (ds1225y_set_to_mode(NVRAM, writemode, "wb"))
> -    {
> -        qemu_fseek(NVRAM->file, pos, SEEK_SET);
> -        qemu_put_byte(NVRAM->file, (int)value);
> +#ifdef DEBUG_NVRAM
> +    printf("nvram: write 0x%x at " TARGET_FMT_lx "\n", val, addr);
> +#endif
> +
> +    pos = addr - s->mem_base;
> +    s->contents[pos] = val & 0xff;
> +    if (s->file) {
> +        qemu_fseek(s->file, pos, SEEK_SET);
> +        qemu_put_byte(s->file, (int)val);
> +        qemu_fflush(s->file);
>      }
>  }
>  
> +static void nvram_writew (void *opaque, target_phys_addr_t addr, uint32_t val)
> +{
> +    nvram_writeb(opaque, addr, val & 0xff);
> +    nvram_writeb(opaque, addr + 1, (val >> 8) & 0xff);
> +}
> +
> +static void nvram_writel (void *opaque, target_phys_addr_t addr, uint32_t val)
> +{
> +    nvram_writeb(opaque, addr, val & 0xff);
> +    nvram_writeb(opaque, addr + 1, (val >> 8) & 0xff);
> +    nvram_writeb(opaque, addr + 2, (val >> 16) & 0xff);
> +    nvram_writeb(opaque, addr + 3, (val >> 24) & 0xff);
> +}
> +
> +static void nvram_writeb_protected (void *opaque, target_phys_addr_t addr, uint32_t val)
> +{
> +    ds1225y_t *s = opaque;
> +
> +    if (s->protection != 7) {
> +#ifdef DEBUG_NVRAM
> +    printf("nvram: prevent write of 0x%x at " TARGET_FMT_lx "\n", val, addr);
> +#endif
> +        return;
> +    }
> +
> +    nvram_writeb(opaque, addr - s->capacity, val);
> +}
> +
> +static void nvram_writew_protected (void *opaque, target_phys_addr_t addr, uint32_t val)
> +{
> +    nvram_writeb_protected(opaque, addr, val & 0xff);
> +    nvram_writeb_protected(opaque, addr + 1, (val >> 8) & 0xff);
> +}
> +
> +static void nvram_writel_protected (void *opaque, target_phys_addr_t addr, uint32_t val)
> +{
> +    nvram_writeb_protected(opaque, addr, val & 0xff);
> +    nvram_writeb_protected(opaque, addr + 1, (val >> 8) & 0xff);
> +    nvram_writeb_protected(opaque, addr + 2, (val >> 16) & 0xff);
> +    nvram_writeb_protected(opaque, addr + 3, (val >> 24) & 0xff);
> +}
> +
>  static CPUReadMemoryFunc *nvram_read[] = {
>      &nvram_readb,
> -    NULL,
> -    NULL,
> +    &nvram_readw,
> +    &nvram_readl,
>  };
>  
>  static CPUWriteMemoryFunc *nvram_write[] = {
>      &nvram_writeb,
> -    NULL,
> -    NULL,
> +    &nvram_writew,
> +    &nvram_writel,
>  };
>  
> -static CPUWriteMemoryFunc *nvram_none[] = {
> -    NULL,
> -    NULL,
> -    NULL,
> +static CPUWriteMemoryFunc *nvram_write_protected[] = {
> +    &nvram_writeb_protected,
> +    &nvram_writew_protected,
> +    &nvram_writel_protected,
>  };
>  
>  /* Initialisation routine */
> -ds1225y_t *ds1225y_init(target_phys_addr_t mem_base, const char *filename)
> +void *ds1225y_init(target_phys_addr_t mem_base, const char *filename)
>  {
>      ds1225y_t *s;
> -    int mem_index1, mem_index2;
> +    int mem_indexRW, mem_indexRP;
> +    QEMUFile *file;
>  
>      s = qemu_mallocz(sizeof(ds1225y_t));
>      if (!s)
>          return NULL;
> -    s->mem_base = mem_base;
>      s->capacity = 0x2000; /* Fixed for ds1225y chip: 8K */
> -    s->filename = filename;
> +    s->contents = qemu_mallocz(s->capacity);
> +    if (!s->contents) {
> +        return NULL;
> +    }
> +    s->mem_base = mem_base;
> +    s->protection = 7;
> +
> +    /* Read current file */
> +    file = qemu_fopen(filename, "rb");
> +    if (file) {
> +        qemu_get_buffer(file, s->contents, s->capacity);
> +        qemu_fclose(file);
> +    }
> +    s->file = qemu_fopen(filename, "wb");
> +    if (s->file) {
> +        qemu_put_buffer(s->file, s->contents, s->capacity);
> +        qemu_fflush(s->file);
> +    }

What's the point of writing the file with the exact content that has
just been read?

BTW "capacity" used that way is probably a frenglish word. "size" or
"chip_size" would probably be more correct here.

>      /* Read/write memory */
> -    mem_index1 = cpu_register_io_memory(0, nvram_read, nvram_write, s);
> -    cpu_register_physical_memory(mem_base, s->capacity, mem_index1);
> -    /* Read-only memory */
> -    mem_index2 = cpu_register_io_memory(0, nvram_read, nvram_none, s);
> -    cpu_register_physical_memory(mem_base + s->capacity, s->capacity, mem_index2);
> +    mem_indexRW = cpu_register_io_memory(0, nvram_read, nvram_write, s);
> +    cpu_register_physical_memory(mem_base, s->capacity, mem_indexRW);
> +    /* Read/write protected memory */
> +    mem_indexRP = cpu_register_io_memory(0, nvram_read, nvram_write_protected, s);
> +    cpu_register_physical_memory(mem_base + s->capacity, s->capacity, mem_indexRP);
>      return s;
>  }
> diff --git a/hw/mips.h b/hw/mips.h
> index 0196b6c..f4599a4 100644
> --- a/hw/mips.h
> +++ b/hw/mips.h
> @@ -6,8 +6,8 @@
>  PCIBus *pci_gt64120_init(qemu_irq *pic);
>  
>  /* ds1225y.c */
> -typedef struct ds1225y_t ds1225y_t;
> -ds1225y_t *ds1225y_init(target_phys_addr_t mem_base, const char *filename);
> +void *ds1225y_init(target_phys_addr_t mem_base, const char *filename);
> +void ds1225y_set_protection(void *opaque, int protection);
>  
>  /* mipsnet.c */
>  void mipsnet_init(int base, qemu_irq irq, NICInfo *nd);

-- 
  .''`.  Aurelien Jarno	            | GPG: 1024D/F1BCDB73
 : :' :  Debian developer           | Electrical Engineer
 `. `'   aurel32@debian.org         | aurelien@aurel32.net
   `-    people.debian.org/~aurel32 | www.aurel32.net