/*
* 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