sysdep.h

本源码是将述嵌入式LINUX驱动程序例程

#  define cpu_to_le32p(addr) (cpu_to_le32(*(addr)))
#  define cpu_to_be16p(addr) (cpu_to_be16(*(addr)))
#  define cpu_to_be32p(addr) (cpu_to_be32(*(addr)))

   extern inline void cpu_to_le16s(__u16 *a) {*a = cpu_to_le16(*a);}
   extern inline void cpu_to_le32s(__u16 *a) {*a = cpu_to_le32(*a);}
   extern inline void cpu_to_be16s(__u16 *a) {*a = cpu_to_be16(*a);}
   extern inline void cpu_to_be32s(__u16 *a) {*a = cpu_to_be32(*a);}

#  define le16_to_cpup(x) cpu_to_le16p(x)
#  define le32_to_cpup(x) cpu_to_le32p(x)
#  define be16_to_cpup(x) cpu_to_be16p(x)
#  define be32_to_cpup(x) cpu_to_be32p(x)

#  define le16_to_cpus(x) cpu_to_le16s(x)
#  define le32_to_cpus(x) cpu_to_le32s(x)
#  define be16_to_cpus(x) cpu_to_be16s(x)
#  define be32_to_cpus(x) cpu_to_be32s(x)

#endif

#ifdef LINUX_20
#  define __USE_OLD_REBUILD_HEADER__
#endif

/*
 * 2.0 didn't include sema_init, so we make our own - but only if it
 * looks like semaphore.h got included.
 */
#ifdef LINUX_20
#  ifdef MUTEX_LOCKED   /* Only if semaphore.h included */
     extern inline void sema_init (struct semaphore *sem, int val)
     {
         sem->count = val;
         sem->waking = sem->lock = 0;
         sem->wait = NULL;
     }
#  endif
#endif /* LINUX_20 */

/*
 * In 2.0, there is no real need for spinlocks, and they weren't really
 * implemented anyway.
 *
 * XXX the _irqsave variant should be defined eventually to do the
 * right thing.
 */
#ifdef LINUX_20
typedef int spinlock_t;
#  define spin_lock(lock)
#  define spin_unlock(lock)
#  define spin_lock_init(lock)

#  define spin_lock_irqsave(lock,flags) do { \
        save_flags(flags); cli(); } while (0);
#  define spin_unlock_irqrestore(lock,flags) restore_flags(flags);
#endif

/*
 * 2.1 stuffed the "flush" method into the middle of the file_operations
 * structure.  The FOP_NO_FLUSH symbol is for drivers that do not implement
 * flush (most of them), it can be inserted in initializers for all 2.x
 * kernel versions.
 */
#ifdef LINUX_20
#  define FOP_NO_FLUSH   /* nothing */
#  define TAG_LLSEEK    lseek
#  define TAG_POLL      select
#else
#  define FOP_NO_FLUSH  NULL,
#  define TAG_LLSEEK    llseek
#  define TAG_POLL      poll
#endif



/*
 * fasync changed in 2.2.
 */
#ifdef LINUX_20
/*  typedef struct inode *fasync_file; */
#  define fasync_file struct inode *
#else
  typedef int fasync_file;
#endif

/* kill_fasync had less arguments, and a different indirection in the first */
#ifndef LINUX_24
#  define kill_fasync(ptrptr,sig,band)  kill_fasync(*(ptrptr),(sig))
#endif

/* other things that are virtualized: define the new functions for the old k */
#ifdef LINUX_20
#  define in_interrupt() (intr_count!=0)
#  define mdelay(x) udelay((x)*1000)
#  define signal_pending(current)  ((current)->signal & ~(current)->blocked)
#endif

#ifdef LINUX_PCI_H /* only if PCI stuff is being used */
#  ifdef LINUX_20
#    include "pci-compat.h" /* a whole set of replacement functions */
#  else
#    define  pci_release_device(d) /* placeholder, used in 2.0 to free stuff */
#  endif
#endif



/*
 * Some task state stuff
 */

#ifndef set_current_state
#  define set_current_state(s) current->state = (s);
#endif

#ifdef LINUX_20
extern inline void schedule_timeout(int timeout)
{
    current->timeout = jiffies + timeout;
    current->state = TASK_INTERRUPTIBLE;
    schedule();
    current->timeout = 0;
}

extern inline long sleep_on_timeout(wait_queue_head_t *q, signed long timeout)
{
    signed long early = 0;
        
    current->timeout = jiffies + timeout;
    sleep_on (q);
    if (current->timeout > 0) {
        early = current->timeout - jiffies;
        current->timeout = 0;
    }
    return early;
}


extern inline long interruptible_sleep_on_timeout(wait_queue_head_t *q,
                signed long timeout)
{
    signed long early = 0;
        
    current->timeout = jiffies + timeout;
    interruptible_sleep_on (q);
    if (current->timeout > 0) {
        early = current->timeout - jiffies;
        current->timeout = 0;
    }
    return early;
}

#endif /* LINUX_20 */

/*
 * Schedule_task was a late 2.4 addition.
 */
#ifndef LINUX_24
extern inline int schedule_task(struct tq_struct *task)
{
        queue_task(task, &tq_scheduler);
        return 1;
}
#endif


/*
 * Timing issues
 */
#ifdef LINUX_20
#  define get_fast_time do_gettimeofday
#endif

#ifdef _LINUX_DELAY_H /* only if linux/delay.h is included */
#  ifndef mdelay /* linux-2.0 */
#    ifndef MAX_UDELAY_MS
#      define MAX_UDELAY_MS   5
#    endif
#    define mdelay(n) (\
        (__builtin_constant_p(n) && (n)<=MAX_UDELAY_MS) ? udelay((n)*1000) : \
        ({unsigned long msec=(n); while (msec--) udelay(1000);}))
#  endif /* mdelay */
#endif /* _LINUX_DELAY_H */


/*
 * No del_timer_sync before 2.4
 */
#ifndef LINUX_24
#  define del_timer_sync(timer) del_timer(timer)  /* and hope */
#endif

/*
 * mod_timer wasn't present in 2.0
 */
#ifdef LINUX_20
static inline int mod_timer(struct timer_list *timer, unsigned long expires)
{
    int pending = del_timer(timer);
    if (pending) {
        timer->expires = expires;
        add_timer(timer);
    }
    return pending;
}
#endif
/*
 * Various changes in mmap and friends.
 */

#ifndef NOPAGE_SIGBUS
#  define NOPAGE_SIGBUS  NULL  /* return value of the nopage memory method */
#  define NOPAGE_OOM     NULL  /* No real equivalent in older kernels */
#endif

#ifndef VM_RESERVED            /* Added 2.4.0-test10 */
#  define VM_RESERVED 0
#endif

#ifdef LINUX_24 /* use "vm_pgoff" to get an offset */
#define VMA_OFFSET(vma)  ((vma)->vm_pgoff << PAGE_SHIFT)
#else /* use "vm_offset" */
#define VMA_OFFSET(vma)  ((vma)->vm_offset)
#endif

#ifdef MAP_NR
#define virt_to_page(page) (mem_map + MAP_NR(page))
#endif

#ifndef get_page
#  define get_page(p) atomic_inc(&(p)->count)
#endif

/*
 * No DMA lock in 2.0.
 */
#ifdef LINUX_20
static inline unsigned long claim_dma_lock(void)
{
    unsigned long flags;
    save_flags(flags);
    cli();
    return flags;
}

static inline void release_dma_lock(unsigned long flags)
{
    restore_flags(flags);
}
#endif


/*
 * I/O memory was not managed by ealier kernels, define them as success
 */

#if 0 /* FIXME: what is the right way to do request_mem_region? */
#ifndef LINUX_24
#  define check_mem_region(start, len)          0
#  define request_mem_region(start, len, name)  0
#  define release_mem_region(start, len)        0

   /*
    * Also, request_ and release_ region used to return void. Return 0 instead
    */
#  define request_region(s, l, n)  ({request_region((s),(l),(n));0;})
#  define release_region(s, l)     ({release_region((s),(l));0;})

#endif /* not LINUX_24 */
#endif

/*
 * Block layer stuff.
 */
#ifndef LINUX_24

/* BLK_DEFAULT_QUEUE for use with these macros only!!!! */
#define BLK_DEFAULT_QUEUE(major) blk_dev[(major)].request_fn
#define blk_init_queue(where,request_fn) where = request_fn;
#define blk_cleanup_queue(where) where = NULL;

/* No QUEUE_EMPTY in older kernels */
#ifndef QUEUE_EMPTY  /* Driver can redefine it too */
#  define QUEUE_EMPTY (CURRENT != NULL)
#endif

#ifdef RO_IOCTLS
static inline int blk_ioctl(kdev_t dev, unsigned int cmd, unsigned long arg)
{
    int err;

    switch (cmd) {
      case BLKRAGET: /* return the readahead value */
        if (!arg)  return -EINVAL;
        err = ! access_ok(VERIFY_WRITE, arg, sizeof(long));
        if (err) return -EFAULT;
        PUT_USER(read_ahead[MAJOR(dev)],(long *) arg);
        return 0;

      case BLKRASET: /* set the readahead value */
        if (!capable(CAP_SYS_ADMIN)) return -EACCES;
        if (arg > 0xff) return -EINVAL; /* limit it */
        read_ahead[MAJOR(dev)] = arg;
        return 0;

      case BLKFLSBUF: /* flush */
        if (! capable(CAP_SYS_ADMIN)) return -EACCES; /* only root */
        fsync_dev(dev);
        invalidate_buffers(dev);
        return 0;

        RO_IOCTLS(dev, arg);
    }
    return -ENOTTY;
}
#endif  /* RO_IOCTLS */

#ifdef LINUX_EXTENDED_PARTITION /* defined in genhd.h */
static inline void register_disk(struct gendisk *gdev, kdev_t dev,
                unsigned minors, struct file_operations *ops, long size)
{
    if (! gdev)
        return;
    resetup_one_dev(gdev, MINOR(dev) >> gdev->minor_shift);
}
#endif /* LINUX_EXTENDED_PARTITION */


#else  /* it is Linux 2.4 */
#define HAVE_BLKPG_H
#endif /* LINUX_24 */



#ifdef LINUX_20 /* physical and virtual addresses had the same value */
#  define __pa(a) (a)
#  define __va(a) (a)
#endif

/*
 * Network driver compatibility
 */

/*
 * 2.0 dev_kfree_skb had an extra arg.  The following is a little dangerous
 * in that it assumes that FREE_WRITE is always wanted.  Very few 2.0 drivers
 * use FREE_READ, but the number is *not* zero...
 *
 * Also: implement the non-checking versions of a couple skb functions -
 * but they still check in 2.0.
 */
#ifdef LINUX_20
#  define dev_kfree_skb(skb) dev_kfree_skb((skb), FREE_WRITE);

#  define __skb_push(skb, len) skb_push((skb), (len))
#  define __skb_put(skb, len)  skb_put((skb), (len))
#endif

/*
 * Softnet changes in 2.4
 */
#ifndef LINUX_24
#  ifdef _LINUX_NETDEVICE_H /* only if netdevice.h was included */
#  define netif_start_queue(dev) clear_bit(0, (void *) &(dev)->tbusy);
#  define netif_stop_queue(dev)  set_bit(0, (void *) &(dev)->tbusy);

static inline void netif_wake_queue(struct device *dev)
{
    clear_bit(0, (void *) &(dev)->tbusy);
    mark_bh(NET_BH);
}

/* struct device became struct net_device */
#  define net_device device
#  endif /* netdevice.h */
#endif /* ! LINUX_24 */

/*
 * Memory barrier stuff, define what's missing from older kernel versions
 */
#ifdef switch_to /* this is always a macro, defined in <asm/sysstem.h> */

#  ifndef set_mb
#    define set_mb(var, value) do {(var) = (value); mb();}  while 0
#  endif
#  ifndef set_rmb
#    define set_rmb(var, value) do {(var) = (value); rmb();}  while 0
#  endif
#  ifndef set_wmb
#    define set_wmb(var, value) do {(var) = (value); wmb();}  while 0
#  endif

/* The hw barriers are defined as sw barriers. A correct thing if this
   specific kernel/platform is supported but has no specific instruction */
#  ifndef mb
#    define mb barrier
#  endif
#  ifndef rmb
#    define rmb barrier
#  endif
#  ifndef wmb
#    define wmb barrier
#  endif

#endif /* switch to (i.e. <asm/system.h>) */


#endif /* _SYSDEP_H_ */