idals.h

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/* 
 * Author(s)......: Holger Smolinski <[email protected]>
 *          Martin Schwidefsky <[email protected]>
 * Bugreports.to..: <[email protected]>
 * Copyright IBM Corp. 2000
 *
 * History of changes
 * 07/24/00 new file
 * 05/04/02 code restructuring.
 */

#ifndef _S390_IDALS_H
#define _S390_IDALS_H

#include <linux/errno.h>
#include <linux/err.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <asm/cio.h>
#include <asm/uaccess.h>

#ifdef CONFIG_64BIT
#define IDA_SIZE_LOG 12 /* 11 for 2k , 12 for 4k */
#else
#define IDA_SIZE_LOG 11 /* 11 for 2k , 12 for 4k */
#endif
#define IDA_BLOCK_SIZE (1L<<IDA_SIZE_LOG)

/*
 * Test if an address/length pair needs an idal list.
 */
static inline int
idal_is_needed(void *vaddr, unsigned int length)
{
#ifdef CONFIG_64BIT
    return ((__pa(vaddr) + length - 1) >> 31) != 0;
#else
    return 0;
#endif
}


/*
 * Return the number of idal words needed for an address/length pair.
 */
static inline unsigned int idal_nr_words(void *vaddr, unsigned int length)
{
    return ((__pa(vaddr) & (IDA_BLOCK_SIZE-1)) + length +
        (IDA_BLOCK_SIZE-1)) >> IDA_SIZE_LOG;
}

/*
 * Create the list of idal words for an address/length pair.
 */
static inline unsigned long *idal_create_words(unsigned long *idaws,
                           void *vaddr, unsigned int length)
{
    unsigned long paddr;
    unsigned int cidaw;

    paddr = __pa(vaddr);
    cidaw = ((paddr & (IDA_BLOCK_SIZE-1)) + length + 
         (IDA_BLOCK_SIZE-1)) >> IDA_SIZE_LOG;
    *idaws++ = paddr;
    paddr &= -IDA_BLOCK_SIZE;
    while (--cidaw > 0) {
        paddr += IDA_BLOCK_SIZE;
        *idaws++ = paddr;
    }
    return idaws;
}

/*
 * Sets the address of the data in CCW.
 * If necessary it allocates an IDAL and sets the appropriate flags.
 */
static inline int
set_normalized_cda(struct ccw1 * ccw, void *vaddr)
{
#ifdef CONFIG_64BIT
    unsigned int nridaws;
    unsigned long *idal;

    if (ccw->flags & CCW_FLAG_IDA)
        return -EINVAL;
    nridaws = idal_nr_words(vaddr, ccw->count);
    if (nridaws > 0) {
        idal = kmalloc(nridaws * sizeof(unsigned long),
                   GFP_ATOMIC | GFP_DMA );
        if (idal == NULL)
            return -ENOMEM;
        idal_create_words(idal, vaddr, ccw->count);
        ccw->flags |= CCW_FLAG_IDA;
        vaddr = idal;
    }
#endif
    ccw->cda = (__u32)(unsigned long) vaddr;
    return 0;
}

/*
 * Releases any allocated IDAL related to the CCW.
 */
static inline void
clear_normalized_cda(struct ccw1 * ccw)
{
#ifdef CONFIG_64BIT
    if (ccw->flags & CCW_FLAG_IDA) {
        kfree((void *)(unsigned long) ccw->cda);
        ccw->flags &= ~CCW_FLAG_IDA;
    }
#endif
    ccw->cda = 0;
}

/*
 * Idal buffer extension
 */
struct idal_buffer {
    size_t size;
    size_t page_order;
    void *data[0];
};

/*
 * Allocate an idal buffer
 */
static inline struct idal_buffer *
idal_buffer_alloc(size_t size, int page_order)
{
    struct idal_buffer *ib;
    int nr_chunks, nr_ptrs, i;

    nr_ptrs = (size + IDA_BLOCK_SIZE - 1) >> IDA_SIZE_LOG;
    nr_chunks = (4096 << page_order) >> IDA_SIZE_LOG;
    ib = kmalloc(sizeof(struct idal_buffer) + nr_ptrs*sizeof(void *),
             GFP_DMA | GFP_KERNEL);
    if (ib == NULL)
        return ERR_PTR(-ENOMEM);
    ib->size = size;
    ib->page_order = page_order;
    for (i = 0; i < nr_ptrs; i++) {
        if ((i & (nr_chunks - 1)) != 0) {
            ib->data[i] = ib->data[i-1] + IDA_BLOCK_SIZE;
            continue;
        }
        ib->data[i] = (void *)
            __get_free_pages(GFP_KERNEL, page_order);
        if (ib->data[i] != NULL)
            continue;
        // Not enough memory
        while (i >= nr_chunks) {
            i -= nr_chunks;
            free_pages((unsigned long) ib->data[i],
                   ib->page_order);
        }
        kfree(ib);
        return ERR_PTR(-ENOMEM);
    }
    return ib;
}

/*
 * Free an idal buffer.
 */
static inline void
idal_buffer_free(struct idal_buffer *ib)
{
    int nr_chunks, nr_ptrs, i;

    nr_ptrs = (ib->size + IDA_BLOCK_SIZE - 1) >> IDA_SIZE_LOG;
    nr_chunks = (4096 << ib->page_order) >> IDA_SIZE_LOG;
    for (i = 0; i < nr_ptrs; i += nr_chunks)
        free_pages((unsigned long) ib->data[i], ib->page_order);
    kfree(ib);
}

/*
 * Test if a idal list is really needed.
 */
static inline int
__idal_buffer_is_needed(struct idal_buffer *ib)
{
#ifdef CONFIG_64BIT
    return ib->size > (4096ul << ib->page_order) ||
        idal_is_needed(ib->data[0], ib->size);
#else
    return ib->size > (4096ul << ib->page_order);
#endif
}

/*
 * Set channel data address to idal buffer.
 */
static inline void
idal_buffer_set_cda(struct idal_buffer *ib, struct ccw1 *ccw)
{
    if (__idal_buffer_is_needed(ib)) {
        // setup idals;
        ccw->cda = (u32)(addr_t) ib->data;
        ccw->flags |= CCW_FLAG_IDA;
    } else
        // we do not need idals - use direct addressing
        ccw->cda = (u32)(addr_t) ib->data[0];
    ccw->count = ib->size;
}

/*
 * Copy count bytes from an idal buffer to user memory
 */
static inline size_t
idal_buffer_to_user(struct idal_buffer *ib, void __user *to, size_t count)
{
    size_t left;
    int i;

    BUG_ON(count > ib->size);
    for (i = 0; count > IDA_BLOCK_SIZE; i++) {
        left = copy_to_user(to, ib->data[i], IDA_BLOCK_SIZE);
        if (left)
            return left + count - IDA_BLOCK_SIZE;
        to = (void __user *) to + IDA_BLOCK_SIZE;
        count -= IDA_BLOCK_SIZE;
    }
    return copy_to_user(to, ib->data[i], count);
}

/*
 * Copy count bytes from user memory to an idal buffer
 */
static inline size_t
idal_buffer_from_user(struct idal_buffer *ib, const void __user *from, size_t count)
{
    size_t left;
    int i;

    BUG_ON(count > ib->size);
    for (i = 0; count > IDA_BLOCK_SIZE; i++) {
        left = copy_from_user(ib->data[i], from, IDA_BLOCK_SIZE);
        if (left)
            return left + count - IDA_BLOCK_SIZE;
        from = (void __user *) from + IDA_BLOCK_SIZE;
        count -= IDA_BLOCK_SIZE;
    }
    return copy_from_user(ib->data[i], from, count);
}

#endif