io.c

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/*
 * arch/parisc/lib/io.c
 *
 * Copyright (c) Matthew Wilcox 2001 for Hewlett-Packard
 * Copyright (c) Randolph Chung 2001 <[email protected]>
 *
 * IO accessing functions which shouldn't be inlined because they're too big
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <asm/io.h>

/* Copies a block of memory to a device in an efficient manner.
 * Assumes the device can cope with 32-bit transfers.  If it can't,
 * don't use this function.
 */
void memcpy_toio(volatile void __iomem *dst, const void *src, int count)
{
    if (((unsigned long)dst & 3) != ((unsigned long)src & 3))
        goto bytecopy;
    while ((unsigned long)dst & 3) {
        writeb(*(char *)src, dst++);
        src++;
        count--;
    }
    while (count > 3) {
        __raw_writel(*(u32 *)src, dst);
        src += 4;
        dst += 4;
        count -= 4;
    }
 bytecopy:
    while (count--) {
        writeb(*(char *)src, dst++);
        src++;
    }
}

/*
** Copies a block of memory from a device in an efficient manner.
** Assumes the device can cope with 32-bit transfers.  If it can't,
** don't use this function.
**
** CR16 counts on C3000 reading 256 bytes from Symbios 896 RAM:
**  27341/64    = 427 cyc per int
**  61311/128   = 478 cyc per short
**  122637/256  = 479 cyc per byte
** Ergo bus latencies dominant (not transfer size).
**      Minimize total number of transfers at cost of CPU cycles.
**  TODO: only look at src alignment and adjust the stores to dest.
*/
void memcpy_fromio(void *dst, const volatile void __iomem *src, int count)
{
    /* first compare alignment of src/dst */ 
    if ( (((unsigned long)dst ^ (unsigned long)src) & 1) || (count < 2) )
        goto bytecopy;

    if ( (((unsigned long)dst ^ (unsigned long)src) & 2) || (count < 4) )
        goto shortcopy;

    /* Then check for misaligned start address */
    if ((unsigned long)src & 1) {
        *(u8 *)dst = readb(src);
        src++;
        dst++;
        count--;
        if (count < 2) goto bytecopy;
    }

    if ((unsigned long)src & 2) {
        *(u16 *)dst = __raw_readw(src);
        src += 2;
        dst += 2;
        count -= 2;
    }

    while (count > 3) {
        *(u32 *)dst = __raw_readl(src);
        dst += 4;
        src += 4;
        count -= 4;
    }

 shortcopy:
    while (count > 1) {
        *(u16 *)dst = __raw_readw(src);
        src += 2;
        dst += 2;
        count -= 2;
    }

 bytecopy:
    while (count--) {
        *(char *)dst = readb(src);
        src++;
        dst++;
    }
}

/* Sets a block of memory on a device to a given value.
 * Assumes the device can cope with 32-bit transfers.  If it can't,
 * don't use this function.
 */
void memset_io(volatile void __iomem *addr, unsigned char val, int count)
{
    u32 val32 = (val << 24) | (val << 16) | (val << 8) | val;
    while ((unsigned long)addr & 3) {
        writeb(val, addr++);
        count--;
    }
    while (count > 3) {
        __raw_writel(val32, addr);
        addr += 4;
        count -= 4;
    }
    while (count--) {
        writeb(val, addr++);
    }
}

/*
 * Read COUNT 8-bit bytes from port PORT into memory starting at
 * SRC.
 */
void insb (unsigned long port, void *dst, unsigned long count)
{
    unsigned char *p;

    p = (unsigned char *)dst;

    while (((unsigned long)p) & 0x3) {
        if (!count)
            return;
        count--;
        *p = inb(port);
        p++;
    }

    while (count >= 4) {
        unsigned int w;
        count -= 4;
        w = inb(port) << 24;
        w |= inb(port) << 16;
        w |= inb(port) << 8;
        w |= inb(port);
        *(unsigned int *) p = w;
        p += 4;
    }

    while (count) {
        --count;
        *p = inb(port);
        p++;
    }
}


/*
 * Read COUNT 16-bit words from port PORT into memory starting at
 * SRC.  SRC must be at least short aligned.  This is used by the
 * IDE driver to read disk sectors.  Performance is important, but
 * the interfaces seems to be slow: just using the inlined version
 * of the inw() breaks things.
 */
void insw (unsigned long port, void *dst, unsigned long count)
{
    unsigned int l = 0, l2;
    unsigned char *p;

    p = (unsigned char *)dst;
    
    if (!count)
        return;
    
    switch (((unsigned long)p) & 0x3)
    {
     case 0x00:         /* Buffer 32-bit aligned */
        while (count>=2) {
            
            count -= 2;
            l = cpu_to_le16(inw(port)) << 16;
            l |= cpu_to_le16(inw(port));
            *(unsigned int *)p = l;
            p += 4;
        }
        if (count) {
            *(unsigned short *)p = cpu_to_le16(inw(port));
        }
        break;
    
     case 0x02:         /* Buffer 16-bit aligned */
        *(unsigned short *)p = cpu_to_le16(inw(port));
        p += 2;
        count--;
        while (count>=2) {
            
            count -= 2;
            l = cpu_to_le16(inw(port)) << 16;
            l |= cpu_to_le16(inw(port));
            *(unsigned int *)p = l;
            p += 4;
        }
        if (count) {
            *(unsigned short *)p = cpu_to_le16(inw(port));
        }
        break;
        
     case 0x01:         /* Buffer 8-bit aligned */
     case 0x03:
        /* I don't bother with 32bit transfers
         * in this case, 16bit will have to do -- DE */
        --count;
        
        l = cpu_to_le16(inw(port));
        *p = l >> 8;
        p++;
        while (count--)
        {
            l2 = cpu_to_le16(inw(port));
            *(unsigned short *)p = (l & 0xff) << 8 | (l2 >> 8);
            p += 2;
            l = l2;
        }
        *p = l & 0xff;
        break;
    }
}



/*
 * Read COUNT 32-bit words from port PORT into memory starting at
 * SRC. Now works with any alignment in SRC. Performance is important,
 * but the interfaces seems to be slow: just using the inlined version
 * of the inl() breaks things.
 */
void insl (unsigned long port, void *dst, unsigned long count)
{
    unsigned int l = 0, l2;
    unsigned char *p;

    p = (unsigned char *)dst;
    
    if (!count)
        return;
    
    switch (((unsigned long) dst) & 0x3)
    {
     case 0x00:         /* Buffer 32-bit aligned */
        while (count--)
        {
            *(unsigned int *)p = cpu_to_le32(inl(port));
            p += 4;
        }
        break;
    
     case 0x02:         /* Buffer 16-bit aligned */
        --count;
        
        l = cpu_to_le32(inl(port));
        *(unsigned short *)p = l >> 16;
        p += 2;
        
        while (count--)
        {
            l2 = cpu_to_le32(inl(port));
            *(unsigned int *)p = (l & 0xffff) << 16 | (l2 >> 16);
            p += 4;
            l = l2;
        }
        *(unsigned short *)p = l & 0xffff;
        break;
     case 0x01:         /* Buffer 8-bit aligned */
        --count;
        
        l = cpu_to_le32(inl(port));
        *(unsigned char *)p = l >> 24;
        p++;
        *(unsigned short *)p = (l >> 8) & 0xffff;
        p += 2;
        while (count--)
        {
            l2 = cpu_to_le32(inl(port));
            *(unsigned int *)p = (l & 0xff) << 24 | (l2 >> 8);
            p += 4;
            l = l2;
        }
        *p = l & 0xff;
        break;
     case 0x03:         /* Buffer 8-bit aligned */
        --count;
        
        l = cpu_to_le32(inl(port));
        *p = l >> 24;
        p++;
        while (count--)
        {
            l2 = cpu_to_le32(inl(port));
            *(unsigned int *)p = (l & 0xffffff) << 8 | l2 >> 24;
            p += 4;
            l = l2;
        }
        *(unsigned short *)p = (l >> 8) & 0xffff;
        p += 2;
        *p = l & 0xff;
        break;
    }
}


/*
 * Like insb but in the opposite direction.
 * Don't worry as much about doing aligned memory transfers:
 * doing byte reads the "slow" way isn't nearly as slow as
 * doing byte writes the slow way (no r-m-w cycle).
 */
void outsb(unsigned long port, const void * src, unsigned long count)
{
    const unsigned char *p;

    p = (const unsigned char *)src;
    while (count) {
        count--;
        outb(*p, port);
        p++;
    }
}

/*
 * Like insw but in the opposite direction.  This is used by the IDE
 * driver to write disk sectors.  Performance is important, but the
 * interfaces seems to be slow: just using the inlined version of the
 * outw() breaks things.
 */
void outsw (unsigned long port, const void *src, unsigned long count)
{
    unsigned int l = 0, l2;
    const unsigned char *p;

    p = (const unsigned char *)src;
    
    if (!count)
        return;
    
    switch (((unsigned long)p) & 0x3)
    {
     case 0x00:         /* Buffer 32-bit aligned */
        while (count>=2) {
            count -= 2;
            l = *(unsigned int *)p;
            p += 4;
            outw(le16_to_cpu(l >> 16), port);
            outw(le16_to_cpu(l & 0xffff), port);
        }
        if (count) {
            outw(le16_to_cpu(*(unsigned short*)p), port);
        }
        break;
    
     case 0x02:         /* Buffer 16-bit aligned */
        
        outw(le16_to_cpu(*(unsigned short*)p), port);
        p += 2;
        count--;
        
        while (count>=2) {
            count -= 2;
            l = *(unsigned int *)p;
            p += 4;
            outw(le16_to_cpu(l >> 16), port);
            outw(le16_to_cpu(l & 0xffff), port);
        }
        if (count) {
            outw(le16_to_cpu(*(unsigned short *)p), port);
        }
        break;
        
     case 0x01:         /* Buffer 8-bit aligned */  
        /* I don't bother with 32bit transfers
         * in this case, 16bit will have to do -- DE */
        
        l  = *p << 8;
        p++;
        count--;
        while (count)
        {
            count--;
            l2 = *(unsigned short *)p;
            p += 2;
            outw(le16_to_cpu(l | l2 >> 8), port);
                l = l2 << 8;
        }
        l2 = *(unsigned char *)p;
        outw (le16_to_cpu(l | l2>>8), port);
        break;
    
    }
}


/*
 * Like insl but in the opposite direction.  This is used by the IDE
 * driver to write disk sectors.  Works with any alignment in SRC.
 *  Performance is important, but the interfaces seems to be slow:
 * just using the inlined version of the outl() breaks things.
 */
void outsl (unsigned long port, const void *src, unsigned long count)
{
    unsigned int l = 0, l2;
    const unsigned char *p;

    p = (const unsigned char *)src;
    
    if (!count)
        return;
    
    switch (((unsigned long)p) & 0x3)
    {
     case 0x00:         /* Buffer 32-bit aligned */
        while (count--)
        {
            outl(le32_to_cpu(*(unsigned int *)p), port);
            p += 4;
        }
        break;
    
     case 0x02:         /* Buffer 16-bit aligned */
        --count;
        
        l = *(unsigned short *)p;
        p += 2;
        
        while (count--)
        {
            l2 = *(unsigned int *)p;
            p += 4;
            outl (le32_to_cpu(l << 16 | l2 >> 16), port);
            l = l2;
        }
        l2 = *(unsigned short *)p;
        outl (le32_to_cpu(l << 16 | l2), port);
        break;
     case 0x01:         /* Buffer 8-bit aligned */
        --count;

        l = *p << 24;
        p++;
        l |= *(unsigned short *)p << 8;
        p += 2;

        while (count--)
        {
            l2 = *(unsigned int *)p;
            p += 4;
            outl (le32_to_cpu(l | l2 >> 24), port);
            l = l2 << 8;
        }
        l2 = *p;
        outl (le32_to_cpu(l | l2), port);
        break;
     case 0x03:         /* Buffer 8-bit aligned */
        --count;
        
        l = *p << 24;
        p++;

        while (count--)
        {
            l2 = *(unsigned int *)p;
            p += 4;
            outl (le32_to_cpu(l | l2 >> 8), port);
            l = l2 << 24;
        }
        l2 = *(unsigned short *)p << 16;
        p += 2;
        l2 |= *p;
        outl (le32_to_cpu(l | l2), port);
        break;
    }
}

EXPORT_SYMBOL(insb);
EXPORT_SYMBOL(insw);
EXPORT_SYMBOL(insl);
EXPORT_SYMBOL(outsb);
EXPORT_SYMBOL(outsw);
EXPORT_SYMBOL(outsl);