sound/pci/emu10k1/memory.c - kernel/msm-4.19 - Gitiles

 /*
  *  Copyright (c) by Jaroslav Kysela <perex@suse.cz>
  *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
  *
  *  EMU10K1 memory page allocation (PTB area)
  *
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
  *   the Free Software Foundation; either version 2 of the License, or
  *   (at your option) any later version.
  *
  *   This program is distributed in the hope that it will be useful,
  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *   GNU General Public License for more details.
  *
  *   You should have received a copy of the GNU General Public License
  *   along with this program; if not, write to the Free Software
  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  *
  */

 #include <sound/driver.h>
 #include <linux/pci.h>
 #include <linux/time.h>
 #include <sound/core.h>
 #include <sound/emu10k1.h>

 /* page arguments of these two macros are Emu page (4096 bytes), not like
  * aligned pages in others
  */
 #define __set_ptb_entry(emu,page,addr) \
 	(((u32 *)(emu)->ptb_pages.area)[page] = cpu_to_le32(((addr) << 1) | (page)))

 #define UNIT_PAGES		(PAGE_SIZE / EMUPAGESIZE)
 #define MAX_ALIGN_PAGES		(MAXPAGES / UNIT_PAGES)
 /* get aligned page from offset address */
 #define get_aligned_page(offset)	((offset) >> PAGE_SHIFT)
 /* get offset address from aligned page */
 #define aligned_page_offset(page)	((page) << PAGE_SHIFT)

 #if PAGE_SIZE == 4096
 /* page size == EMUPAGESIZE */
 /* fill PTB entrie(s) corresponding to page with addr */
 #define set_ptb_entry(emu,page,addr)	__set_ptb_entry(emu,page,addr)
 /* fill PTB entrie(s) corresponding to page with silence pointer */
 #define set_silent_ptb(emu,page)	__set_ptb_entry(emu,page,emu->silent_page.addr)
 #else
 /* fill PTB entries -- we need to fill UNIT_PAGES entries */
 static inline void set_ptb_entry(struct snd_emu10k1 *emu, int page, dma_addr_t addr)
 {
 	int i;
 	page *= UNIT_PAGES;
 	for (i = 0; i < UNIT_PAGES; i++, page++) {
 		__set_ptb_entry(emu, page, addr);
 		addr += EMUPAGESIZE;
 	}
 }
 static inline void set_silent_ptb(struct snd_emu10k1 *emu, int page)
 {
 	int i;
 	page *= UNIT_PAGES;
 	for (i = 0; i < UNIT_PAGES; i++, page++)
 		/* do not increment ptr */
 		__set_ptb_entry(emu, page, emu->silent_page.addr);
 }
 #endif /* PAGE_SIZE */


 /*
  */
 static int synth_alloc_pages(struct snd_emu10k1 *hw, struct snd_emu10k1_memblk *blk);
 static int synth_free_pages(struct snd_emu10k1 *hw, struct snd_emu10k1_memblk *blk);

 #define get_emu10k1_memblk(l,member)	list_entry(l, struct snd_emu10k1_memblk, member)


 /* initialize emu10k1 part */
 static void emu10k1_memblk_init(struct snd_emu10k1_memblk *blk)
 {
 	blk->mapped_page = -1;
 	INIT_LIST_HEAD(&blk->mapped_link);
 	INIT_LIST_HEAD(&blk->mapped_order_link);
 	blk->map_locked = 0;

 	blk->first_page = get_aligned_page(blk->mem.offset);
 	blk->last_page = get_aligned_page(blk->mem.offset + blk->mem.size - 1);
 	blk->pages = blk->last_page - blk->first_page + 1;
 }

 /*
  * search empty region on PTB with the given size
  *
  * if an empty region is found, return the page and store the next mapped block
  * in nextp
  * if not found, return a negative error code.
  */
 static int search_empty_map_area(struct snd_emu10k1 *emu, int npages, struct list_head **nextp)
 {
 	int page = 0, found_page = -ENOMEM;
 	int max_size = npages;
 	int size;
 	struct list_head *candidate = &emu->mapped_link_head;
 	struct list_head *pos;

 	list_for_each (pos, &emu->mapped_link_head) {
 		struct snd_emu10k1_memblk *blk = get_emu10k1_memblk(pos, mapped_link);
 		snd_assert(blk->mapped_page >= 0, continue);
 		size = blk->mapped_page - page;
 		if (size == npages) {
 			*nextp = pos;
 			return page;
 		}
 		else if (size > max_size) {
 			/* we look for the maximum empty hole */
 			max_size = size;
 			candidate = pos;
 			found_page = page;
 		}
 		page = blk->mapped_page + blk->pages;
 	}
 	size = MAX_ALIGN_PAGES - page;
 	if (size >= max_size) {
 		*nextp = pos;
 		return page;
 	}
 	*nextp = candidate;
 	return found_page;
 }

 /*
  * map a memory block onto emu10k1's PTB
  *
  * call with memblk_lock held
  */
 static int map_memblk(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
 {
 	int page, pg;
 	struct list_head *next;

 	page = search_empty_map_area(emu, blk->pages, &next);
 	if (page < 0) /* not found */
 		return page;
 	/* insert this block in the proper position of mapped list */
 	list_add_tail(&blk->mapped_link, next);
 	/* append this as a newest block in order list */
 	list_add_tail(&blk->mapped_order_link, &emu->mapped_order_link_head);
 	blk->mapped_page = page;
 	/* fill PTB */
 	for (pg = blk->first_page; pg <= blk->last_page; pg++) {
 		set_ptb_entry(emu, page, emu->page_addr_table[pg]);
 		page++;
 	}
 	return 0;
 }

 /*
  * unmap the block
  * return the size of resultant empty pages
  *
  * call with memblk_lock held
  */
 static int unmap_memblk(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
 {
 	int start_page, end_page, mpage, pg;
 	struct list_head *p;
 	struct snd_emu10k1_memblk *q;

 	/* calculate the expected size of empty region */
 	if ((p = blk->mapped_link.prev) != &emu->mapped_link_head) {
 		q = get_emu10k1_memblk(p, mapped_link);
 		start_page = q->mapped_page + q->pages;
 	} else
 		start_page = 0;
 	if ((p = blk->mapped_link.next) != &emu->mapped_link_head) {
 		q = get_emu10k1_memblk(p, mapped_link);
 		end_page = q->mapped_page;
 	} else
 		end_page = MAX_ALIGN_PAGES;

 	/* remove links */
 	list_del(&blk->mapped_link);
 	list_del(&blk->mapped_order_link);
 	/* clear PTB */
 	mpage = blk->mapped_page;
 	for (pg = blk->first_page; pg <= blk->last_page; pg++) {
 		set_silent_ptb(emu, mpage);
 		mpage++;
 	}
 	blk->mapped_page = -1;
 	return end_page - start_page; /* return the new empty size */
 }

 /*
  * search empty pages with the given size, and create a memory block
  *
  * unlike synth_alloc the memory block is aligned to the page start
  */
 static struct snd_emu10k1_memblk *
 search_empty(struct snd_emu10k1 *emu, int size)
 {
 	struct list_head *p;
 	struct snd_emu10k1_memblk *blk;
 	int page, psize;

 	psize = get_aligned_page(size + PAGE_SIZE -1);
 	page = 0;
 	list_for_each(p, &emu->memhdr->block) {
 		blk = get_emu10k1_memblk(p, mem.list);
 		if (page + psize <= blk->first_page)
 			goto __found_pages;
 		page = blk->last_page + 1;
 	}
 	if (page + psize > emu->max_cache_pages)
 		return NULL;

 __found_pages:
 	/* create a new memory block */
 	blk = (struct snd_emu10k1_memblk *)__snd_util_memblk_new(emu->memhdr, psize << PAGE_SHIFT, p->prev);
 	if (blk == NULL)
 		return NULL;
 	blk->mem.offset = aligned_page_offset(page); /* set aligned offset */
 	emu10k1_memblk_init(blk);
 	return blk;
 }


 /*
  * check if the given pointer is valid for pages
  */
 static int is_valid_page(struct snd_emu10k1 *emu, dma_addr_t addr)
 {
 	if (addr & ~emu->dma_mask) {
 		snd_printk(KERN_ERR "max memory size is 0x%lx (addr = 0x%lx)!!\n", emu->dma_mask, (unsigned long)addr);
 		return 0;
 	}
 	if (addr & (EMUPAGESIZE-1)) {
 		snd_printk(KERN_ERR "page is not aligned\n");
 		return 0;
 	}
 	return 1;
 }

 /*
  * map the given memory block on PTB.
  * if the block is already mapped, update the link order.
  * if no empty pages are found, tries to release unsed memory blocks
  * and retry the mapping.
  */
 int snd_emu10k1_memblk_map(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
 {
 	int err;
 	int size;
 	struct list_head *p, *nextp;
 	struct snd_emu10k1_memblk *deleted;
 	unsigned long flags;

 	spin_lock_irqsave(&emu->memblk_lock, flags);
 	if (blk->mapped_page >= 0) {
 		/* update order link */
 		list_del(&blk->mapped_order_link);
 		list_add_tail(&blk->mapped_order_link, &emu->mapped_order_link_head);
 		spin_unlock_irqrestore(&emu->memblk_lock, flags);
 		return 0;
 	}
 	if ((err = map_memblk(emu, blk)) < 0) {
 		/* no enough page - try to unmap some blocks */
 		/* starting from the oldest block */
 		p = emu->mapped_order_link_head.next;
 		for (; p != &emu->mapped_order_link_head; p = nextp) {
 			nextp = p->next;
 			deleted = get_emu10k1_memblk(p, mapped_order_link);
 			if (deleted->map_locked)
 				continue;
 			size = unmap_memblk(emu, deleted);
 			if (size >= blk->pages) {
 				/* ok the empty region is enough large */
 				err = map_memblk(emu, blk);
 				break;
 			}
 		}
 	}
 	spin_unlock_irqrestore(&emu->memblk_lock, flags);
 	return err;
 }

 /*
  * page allocation for DMA
  */
 struct snd_util_memblk *
 snd_emu10k1_alloc_pages(struct snd_emu10k1 *emu, struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);
 	struct snd_util_memhdr *hdr;
 	struct snd_emu10k1_memblk *blk;
 	int page, err, idx;

 	snd_assert(emu, return NULL);
 	snd_assert(runtime->dma_bytes > 0 && runtime->dma_bytes < MAXPAGES * EMUPAGESIZE, return NULL);
 	hdr = emu->memhdr;
 	snd_assert(hdr, return NULL);

 	down(&hdr->block_mutex);
 	blk = search_empty(emu, runtime->dma_bytes);
 	if (blk == NULL) {
 		up(&hdr->block_mutex);
 		return NULL;
 	}
 	/* fill buffer addresses but pointers are not stored so that
 	 * snd_free_pci_page() is not called in in synth_free()
 	 */
 	idx = 0;
 	for (page = blk->first_page; page <= blk->last_page; page++, idx++) {
 		dma_addr_t addr;
 #ifdef CONFIG_SND_DEBUG
 		if (idx >= sgbuf->pages) {
 			printk(KERN_ERR "emu: pages overflow! (%d-%d) for %d\n",
 			       blk->first_page, blk->last_page, sgbuf->pages);
 			up(&hdr->block_mutex);
 			return NULL;
 		}
 #endif
 		addr = sgbuf->table[idx].addr;
 		if (! is_valid_page(emu, addr)) {
 			printk(KERN_ERR "emu: failure page = %d\n", idx);
 			up(&hdr->block_mutex);
 			return NULL;
 		}
 		emu->page_addr_table[page] = addr;
 		emu->page_ptr_table[page] = NULL;
 	}

 	/* set PTB entries */
 	blk->map_locked = 1; /* do not unmap this block! */
 	err = snd_emu10k1_memblk_map(emu, blk);
 	if (err < 0) {
 		__snd_util_mem_free(hdr, (struct snd_util_memblk *)blk);
 		up(&hdr->block_mutex);
 		return NULL;
 	}
 	up(&hdr->block_mutex);
 	return (struct snd_util_memblk *)blk;
 }


 /*
  * release DMA buffer from page table
  */
 int snd_emu10k1_free_pages(struct snd_emu10k1 *emu, struct snd_util_memblk *blk)
 {
 	snd_assert(emu && blk, return -EINVAL);
 	return snd_emu10k1_synth_free(emu, blk);
 }


 /*
  * memory allocation using multiple pages (for synth)
  * Unlike the DMA allocation above, non-contiguous pages are assined.
  */

 /*
  * allocate a synth sample area
  */
 struct snd_util_memblk *
 snd_emu10k1_synth_alloc(struct snd_emu10k1 *hw, unsigned int size)
 {
 	struct snd_emu10k1_memblk *blk;
 	struct snd_util_memhdr *hdr = hw->memhdr;

 	down(&hdr->block_mutex);
 	blk = (struct snd_emu10k1_memblk *)__snd_util_mem_alloc(hdr, size);
 	if (blk == NULL) {
 		up(&hdr->block_mutex);
 		return NULL;
 	}
 	if (synth_alloc_pages(hw, blk)) {
 		__snd_util_mem_free(hdr, (struct snd_util_memblk *)blk);
 		up(&hdr->block_mutex);
 		return NULL;
 	}
 	snd_emu10k1_memblk_map(hw, blk);
 	up(&hdr->block_mutex);
 	return (struct snd_util_memblk *)blk;
 }


 /*
  * free a synth sample area
  */
 int
 snd_emu10k1_synth_free(struct snd_emu10k1 *emu, struct snd_util_memblk *memblk)
 {
 	struct snd_util_memhdr *hdr = emu->memhdr;
 	struct snd_emu10k1_memblk *blk = (struct snd_emu10k1_memblk *)memblk;
 	unsigned long flags;

 	down(&hdr->block_mutex);
 	spin_lock_irqsave(&emu->memblk_lock, flags);
 	if (blk->mapped_page >= 0)
 		unmap_memblk(emu, blk);
 	spin_unlock_irqrestore(&emu->memblk_lock, flags);
 	synth_free_pages(emu, blk);
 	 __snd_util_mem_free(hdr, memblk);
 	up(&hdr->block_mutex);
 	return 0;
 }


 /* check new allocation range */
 static void get_single_page_range(struct snd_util_memhdr *hdr,
 				  struct snd_emu10k1_memblk *blk,
 				  int *first_page_ret, int *last_page_ret)
 {
 	struct list_head *p;
 	struct snd_emu10k1_memblk *q;
 	int first_page, last_page;
 	first_page = blk->first_page;
 	if ((p = blk->mem.list.prev) != &hdr->block) {
 		q = get_emu10k1_memblk(p, mem.list);
 		if (q->last_page == first_page)
 			first_page++;  /* first page was already allocated */
 	}
 	last_page = blk->last_page;
 	if ((p = blk->mem.list.next) != &hdr->block) {
 		q = get_emu10k1_memblk(p, mem.list);
 		if (q->first_page == last_page)
 			last_page--; /* last page was already allocated */
 	}
 	*first_page_ret = first_page;
 	*last_page_ret = last_page;
 }

 /*
  * allocate kernel pages
  */
 static int synth_alloc_pages(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
 {
 	int page, first_page, last_page;
 	struct snd_dma_buffer dmab;

 	emu10k1_memblk_init(blk);
 	get_single_page_range(emu->memhdr, blk, &first_page, &last_page);
 	/* allocate kernel pages */
 	for (page = first_page; page <= last_page; page++) {
 		if (snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, snd_dma_pci_data(emu->pci),
 					PAGE_SIZE, &dmab) < 0)
 			goto __fail;
 		if (! is_valid_page(emu, dmab.addr)) {
 			snd_dma_free_pages(&dmab);
 			goto __fail;
 		}
 		emu->page_addr_table[page] = dmab.addr;
 		emu->page_ptr_table[page] = dmab.area;
 	}
 	return 0;

 __fail:
 	/* release allocated pages */
 	last_page = page - 1;
 	for (page = first_page; page <= last_page; page++) {
 		dmab.area = emu->page_ptr_table[page];
 		dmab.addr = emu->page_addr_table[page];
 		dmab.bytes = PAGE_SIZE;
 		snd_dma_free_pages(&dmab);
 		emu->page_addr_table[page] = 0;
 		emu->page_ptr_table[page] = NULL;
 	}

 	return -ENOMEM;
 }

 /*
  * free pages
  */
 static int synth_free_pages(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
 {
 	int page, first_page, last_page;
 	struct snd_dma_buffer dmab;

 	get_single_page_range(emu->memhdr, blk, &first_page, &last_page);
 	dmab.dev.type = SNDRV_DMA_TYPE_DEV;
 	dmab.dev.dev = snd_dma_pci_data(emu->pci);
 	for (page = first_page; page <= last_page; page++) {
 		if (emu->page_ptr_table[page] == NULL)
 			continue;
 		dmab.area = emu->page_ptr_table[page];
 		dmab.addr = emu->page_addr_table[page];
 		dmab.bytes = PAGE_SIZE;
 		snd_dma_free_pages(&dmab);
 		emu->page_addr_table[page] = 0;
 		emu->page_ptr_table[page] = NULL;
 	}

 	return 0;
 }

 /* calculate buffer pointer from offset address */
 static inline void *offset_ptr(struct snd_emu10k1 *emu, int page, int offset)
 {
 	char *ptr;
 	snd_assert(page >= 0 && page < emu->max_cache_pages, return NULL);
 	ptr = emu->page_ptr_table[page];
 	if (! ptr) {
 		printk(KERN_ERR "emu10k1: access to NULL ptr: page = %d\n", page);
 		return NULL;
 	}
 	ptr += offset & (PAGE_SIZE - 1);
 	return (void*)ptr;
 }

 /*
  * bzero(blk + offset, size)
  */
 int snd_emu10k1_synth_bzero(struct snd_emu10k1 *emu, struct snd_util_memblk *blk,
 			    int offset, int size)
 {
 	int page, nextofs, end_offset, temp, temp1;
 	void *ptr;
 	struct snd_emu10k1_memblk *p = (struct snd_emu10k1_memblk *)blk;

 	offset += blk->offset & (PAGE_SIZE - 1);
 	end_offset = offset + size;
 	page = get_aligned_page(offset);
 	do {
 		nextofs = aligned_page_offset(page + 1);
 		temp = nextofs - offset;
 		temp1 = end_offset - offset;
 		if (temp1 < temp)
 			temp = temp1;
 		ptr = offset_ptr(emu, page + p->first_page, offset);
 		if (ptr)
 			memset(ptr, 0, temp);
 		offset = nextofs;
 		page++;
 	} while (offset < end_offset);
 	return 0;
 }

 /*
  * copy_from_user(blk + offset, data, size)
  */
 int snd_emu10k1_synth_copy_from_user(struct snd_emu10k1 *emu, struct snd_util_memblk *blk,
 				     int offset, const char __user *data, int size)
 {
 	int page, nextofs, end_offset, temp, temp1;
 	void *ptr;
 	struct snd_emu10k1_memblk *p = (struct snd_emu10k1_memblk *)blk;

 	offset += blk->offset & (PAGE_SIZE - 1);
 	end_offset = offset + size;
 	page = get_aligned_page(offset);
 	do {
 		nextofs = aligned_page_offset(page + 1);
 		temp = nextofs - offset;
 		temp1 = end_offset - offset;
 		if (temp1 < temp)
 			temp = temp1;
 		ptr = offset_ptr(emu, page + p->first_page, offset);
 		if (ptr && copy_from_user(ptr, data, temp))
 			return -EFAULT;
 		offset = nextofs;
 		data += temp;
 		page++;
 	} while (offset < end_offset);
 	return 0;
 }
	/*
	* Copyright (c) by Jaroslav Kysela <perex@suse.cz>
	* Copyright (c) by Takashi Iwai <tiwai@suse.de>
	*
	* EMU10K1 memory page allocation (PTB area)
	*
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*
	*/

	#include <sound/driver.h>
	#include <linux/pci.h>
	#include <linux/time.h>
	#include <sound/core.h>
	#include <sound/emu10k1.h>

	/* page arguments of these two macros are Emu page (4096 bytes), not like
	* aligned pages in others
	*/
	#define __set_ptb_entry(emu,page,addr) \
	(((u32 *)(emu)->ptb_pages.area)[page] = cpu_to_le32(((addr) << 1) \| (page)))

	#define UNIT_PAGES (PAGE_SIZE / EMUPAGESIZE)
	#define MAX_ALIGN_PAGES (MAXPAGES / UNIT_PAGES)
	/* get aligned page from offset address */
	#define get_aligned_page(offset) ((offset) >> PAGE_SHIFT)
	/* get offset address from aligned page */
	#define aligned_page_offset(page) ((page) << PAGE_SHIFT)

	#if PAGE_SIZE == 4096
	/* page size == EMUPAGESIZE */
	/* fill PTB entrie(s) corresponding to page with addr */
	#define set_ptb_entry(emu,page,addr) __set_ptb_entry(emu,page,addr)
	/* fill PTB entrie(s) corresponding to page with silence pointer */
	#define set_silent_ptb(emu,page) __set_ptb_entry(emu,page,emu->silent_page.addr)
	#else
	/* fill PTB entries -- we need to fill UNIT_PAGES entries */
	static inline void set_ptb_entry(struct snd_emu10k1 *emu, int page, dma_addr_t addr)
	{
	int i;
	page *= UNIT_PAGES;
	for (i = 0; i < UNIT_PAGES; i++, page++) {
	__set_ptb_entry(emu, page, addr);
	addr += EMUPAGESIZE;
	}
	}
	static inline void set_silent_ptb(struct snd_emu10k1 *emu, int page)
	{
	int i;
	page *= UNIT_PAGES;
	for (i = 0; i < UNIT_PAGES; i++, page++)
	/* do not increment ptr */
	__set_ptb_entry(emu, page, emu->silent_page.addr);
	}
	#endif /* PAGE_SIZE */


	/*
	*/
	static int synth_alloc_pages(struct snd_emu10k1 hw, struct snd_emu10k1_memblk blk);
	static int synth_free_pages(struct snd_emu10k1 hw, struct snd_emu10k1_memblk blk);

	#define get_emu10k1_memblk(l,member) list_entry(l, struct snd_emu10k1_memblk, member)


	/* initialize emu10k1 part */
	static void emu10k1_memblk_init(struct snd_emu10k1_memblk *blk)
	{
	blk->mapped_page = -1;
	INIT_LIST_HEAD(&blk->mapped_link);
	INIT_LIST_HEAD(&blk->mapped_order_link);
	blk->map_locked = 0;

	blk->first_page = get_aligned_page(blk->mem.offset);
	blk->last_page = get_aligned_page(blk->mem.offset + blk->mem.size - 1);
	blk->pages = blk->last_page - blk->first_page + 1;
	}

	/*
	* search empty region on PTB with the given size
	*
	* if an empty region is found, return the page and store the next mapped block
	* in nextp
	* if not found, return a negative error code.
	*/
	static int search_empty_map_area(struct snd_emu10k1 emu, int npages, struct list_head *nextp)
	{
	int page = 0, found_page = -ENOMEM;
	int max_size = npages;
	int size;
	struct list_head *candidate = &emu->mapped_link_head;
	struct list_head *pos;

	list_for_each (pos, &emu->mapped_link_head) {
	struct snd_emu10k1_memblk *blk = get_emu10k1_memblk(pos, mapped_link);
	snd_assert(blk->mapped_page >= 0, continue);
	size = blk->mapped_page - page;
	if (size == npages) {
	*nextp = pos;
	return page;
	}
	else if (size > max_size) {
	/* we look for the maximum empty hole */
	max_size = size;
	candidate = pos;
	found_page = page;
	}
	page = blk->mapped_page + blk->pages;
	}
	size = MAX_ALIGN_PAGES - page;
	if (size >= max_size) {
	*nextp = pos;
	return page;
	}
	*nextp = candidate;
	return found_page;
	}

	/*
	* map a memory block onto emu10k1's PTB
	*
	* call with memblk_lock held
	*/
	static int map_memblk(struct snd_emu10k1 emu, struct snd_emu10k1_memblk blk)
	{
	int page, pg;
	struct list_head *next;

	page = search_empty_map_area(emu, blk->pages, &next);
	if (page < 0) /* not found */
	return page;
	/* insert this block in the proper position of mapped list */
	list_add_tail(&blk->mapped_link, next);
	/* append this as a newest block in order list */
	list_add_tail(&blk->mapped_order_link, &emu->mapped_order_link_head);
	blk->mapped_page = page;
	/* fill PTB */
	for (pg = blk->first_page; pg <= blk->last_page; pg++) {
	set_ptb_entry(emu, page, emu->page_addr_table[pg]);
	page++;
	}
	return 0;
	}

	/*
	* unmap the block
	* return the size of resultant empty pages
	*
	* call with memblk_lock held
	*/
	static int unmap_memblk(struct snd_emu10k1 emu, struct snd_emu10k1_memblk blk)
	{
	int start_page, end_page, mpage, pg;
	struct list_head *p;
	struct snd_emu10k1_memblk *q;

	/* calculate the expected size of empty region */
	if ((p = blk->mapped_link.prev) != &emu->mapped_link_head) {
	q = get_emu10k1_memblk(p, mapped_link);
	start_page = q->mapped_page + q->pages;
	} else
	start_page = 0;
	if ((p = blk->mapped_link.next) != &emu->mapped_link_head) {
	q = get_emu10k1_memblk(p, mapped_link);
	end_page = q->mapped_page;
	} else
	end_page = MAX_ALIGN_PAGES;

	/* remove links */
	list_del(&blk->mapped_link);
	list_del(&blk->mapped_order_link);
	/* clear PTB */
	mpage = blk->mapped_page;
	for (pg = blk->first_page; pg <= blk->last_page; pg++) {
	set_silent_ptb(emu, mpage);
	mpage++;
	}
	blk->mapped_page = -1;
	return end_page - start_page; /* return the new empty size */
	}

	/*
	* search empty pages with the given size, and create a memory block
	*
	* unlike synth_alloc the memory block is aligned to the page start
	*/
	static struct snd_emu10k1_memblk *
	search_empty(struct snd_emu10k1 *emu, int size)
	{
	struct list_head *p;
	struct snd_emu10k1_memblk *blk;
	int page, psize;

	psize = get_aligned_page(size + PAGE_SIZE -1);
	page = 0;
	list_for_each(p, &emu->memhdr->block) {
	blk = get_emu10k1_memblk(p, mem.list);
	if (page + psize <= blk->first_page)
	goto __found_pages;
	page = blk->last_page + 1;
	}
	if (page + psize > emu->max_cache_pages)
	return NULL;

	__found_pages:
	/* create a new memory block */
	blk = (struct snd_emu10k1_memblk *)__snd_util_memblk_new(emu->memhdr, psize << PAGE_SHIFT, p->prev);
	if (blk == NULL)
	return NULL;
	blk->mem.offset = aligned_page_offset(page); /* set aligned offset */
	emu10k1_memblk_init(blk);
	return blk;
	}


	/*
	* check if the given pointer is valid for pages
	*/
	static int is_valid_page(struct snd_emu10k1 *emu, dma_addr_t addr)
	{
	if (addr & ~emu->dma_mask) {
	snd_printk(KERN_ERR "max memory size is 0x%lx (addr = 0x%lx)!!\n", emu->dma_mask, (unsigned long)addr);
	return 0;
	}
	if (addr & (EMUPAGESIZE-1)) {
	snd_printk(KERN_ERR "page is not aligned\n");
	return 0;
	}
	return 1;
	}

	/*
	* map the given memory block on PTB.
	* if the block is already mapped, update the link order.
	* if no empty pages are found, tries to release unsed memory blocks
	* and retry the mapping.
	*/
	int snd_emu10k1_memblk_map(struct snd_emu10k1 emu, struct snd_emu10k1_memblk blk)
	{
	int err;
	int size;
	struct list_head p, nextp;
	struct snd_emu10k1_memblk *deleted;
	unsigned long flags;

	spin_lock_irqsave(&emu->memblk_lock, flags);
	if (blk->mapped_page >= 0) {
	/* update order link */
	list_del(&blk->mapped_order_link);
	list_add_tail(&blk->mapped_order_link, &emu->mapped_order_link_head);
	spin_unlock_irqrestore(&emu->memblk_lock, flags);
	return 0;
	}
	if ((err = map_memblk(emu, blk)) < 0) {
	/* no enough page - try to unmap some blocks */
	/* starting from the oldest block */
	p = emu->mapped_order_link_head.next;
	for (; p != &emu->mapped_order_link_head; p = nextp) {
	nextp = p->next;
	deleted = get_emu10k1_memblk(p, mapped_order_link);
	if (deleted->map_locked)
	continue;
	size = unmap_memblk(emu, deleted);
	if (size >= blk->pages) {
	/* ok the empty region is enough large */
	err = map_memblk(emu, blk);
	break;
	}
	}
	}
	spin_unlock_irqrestore(&emu->memblk_lock, flags);
	return err;
	}

	/*
	* page allocation for DMA
	*/
	struct snd_util_memblk *
	snd_emu10k1_alloc_pages(struct snd_emu10k1 emu, struct snd_pcm_substream substream)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);
	struct snd_util_memhdr *hdr;
	struct snd_emu10k1_memblk *blk;
	int page, err, idx;

	snd_assert(emu, return NULL);
	snd_assert(runtime->dma_bytes > 0 && runtime->dma_bytes < MAXPAGES * EMUPAGESIZE, return NULL);
	hdr = emu->memhdr;
	snd_assert(hdr, return NULL);

	down(&hdr->block_mutex);
	blk = search_empty(emu, runtime->dma_bytes);
	if (blk == NULL) {
	up(&hdr->block_mutex);
	return NULL;
	}
	/* fill buffer addresses but pointers are not stored so that
	* snd_free_pci_page() is not called in in synth_free()
	*/
	idx = 0;
	for (page = blk->first_page; page <= blk->last_page; page++, idx++) {
	dma_addr_t addr;
	#ifdef CONFIG_SND_DEBUG
	if (idx >= sgbuf->pages) {
	printk(KERN_ERR "emu: pages overflow! (%d-%d) for %d\n",
	blk->first_page, blk->last_page, sgbuf->pages);
	up(&hdr->block_mutex);
	return NULL;
	}
	#endif
	addr = sgbuf->table[idx].addr;
	if (! is_valid_page(emu, addr)) {
	printk(KERN_ERR "emu: failure page = %d\n", idx);
	up(&hdr->block_mutex);
	return NULL;
	}
	emu->page_addr_table[page] = addr;
	emu->page_ptr_table[page] = NULL;
	}

	/* set PTB entries */
	blk->map_locked = 1; /* do not unmap this block! */
	err = snd_emu10k1_memblk_map(emu, blk);
	if (err < 0) {
	__snd_util_mem_free(hdr, (struct snd_util_memblk *)blk);
	up(&hdr->block_mutex);
	return NULL;
	}
	up(&hdr->block_mutex);
	return (struct snd_util_memblk *)blk;
	}


	/*
	* release DMA buffer from page table
	*/
	int snd_emu10k1_free_pages(struct snd_emu10k1 emu, struct snd_util_memblk blk)
	{
	snd_assert(emu && blk, return -EINVAL);
	return snd_emu10k1_synth_free(emu, blk);
	}


	/*
	* memory allocation using multiple pages (for synth)
	* Unlike the DMA allocation above, non-contiguous pages are assined.
	*/

	/*
	* allocate a synth sample area
	*/
	struct snd_util_memblk *
	snd_emu10k1_synth_alloc(struct snd_emu10k1 *hw, unsigned int size)
	{
	struct snd_emu10k1_memblk *blk;
	struct snd_util_memhdr *hdr = hw->memhdr;

	down(&hdr->block_mutex);
	blk = (struct snd_emu10k1_memblk *)__snd_util_mem_alloc(hdr, size);
	if (blk == NULL) {
	up(&hdr->block_mutex);
	return NULL;
	}
	if (synth_alloc_pages(hw, blk)) {
	__snd_util_mem_free(hdr, (struct snd_util_memblk *)blk);
	up(&hdr->block_mutex);
	return NULL;
	}
	snd_emu10k1_memblk_map(hw, blk);
	up(&hdr->block_mutex);
	return (struct snd_util_memblk *)blk;
	}


	/*
	* free a synth sample area
	*/
	int
	snd_emu10k1_synth_free(struct snd_emu10k1 emu, struct snd_util_memblk memblk)
	{
	struct snd_util_memhdr *hdr = emu->memhdr;
	struct snd_emu10k1_memblk blk = (struct snd_emu10k1_memblk )memblk;
	unsigned long flags;

	down(&hdr->block_mutex);
	spin_lock_irqsave(&emu->memblk_lock, flags);
	if (blk->mapped_page >= 0)
	unmap_memblk(emu, blk);
	spin_unlock_irqrestore(&emu->memblk_lock, flags);
	synth_free_pages(emu, blk);
	__snd_util_mem_free(hdr, memblk);
	up(&hdr->block_mutex);
	return 0;
	}


	/* check new allocation range */
	static void get_single_page_range(struct snd_util_memhdr *hdr,
	struct snd_emu10k1_memblk *blk,
	int first_page_ret, int last_page_ret)
	{
	struct list_head *p;
	struct snd_emu10k1_memblk *q;
	int first_page, last_page;
	first_page = blk->first_page;
	if ((p = blk->mem.list.prev) != &hdr->block) {
	q = get_emu10k1_memblk(p, mem.list);
	if (q->last_page == first_page)
	first_page++; /* first page was already allocated */
	}
	last_page = blk->last_page;
	if ((p = blk->mem.list.next) != &hdr->block) {
	q = get_emu10k1_memblk(p, mem.list);
	if (q->first_page == last_page)
	last_page--; /* last page was already allocated */
	}
	*first_page_ret = first_page;
	*last_page_ret = last_page;
	}

	/*
	* allocate kernel pages
	*/
	static int synth_alloc_pages(struct snd_emu10k1 emu, struct snd_emu10k1_memblk blk)
	{
	int page, first_page, last_page;
	struct snd_dma_buffer dmab;

	emu10k1_memblk_init(blk);
	get_single_page_range(emu->memhdr, blk, &first_page, &last_page);
	/* allocate kernel pages */
	for (page = first_page; page <= last_page; page++) {
	if (snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, snd_dma_pci_data(emu->pci),
	PAGE_SIZE, &dmab) < 0)
	goto __fail;
	if (! is_valid_page(emu, dmab.addr)) {
	snd_dma_free_pages(&dmab);
	goto __fail;
	}
	emu->page_addr_table[page] = dmab.addr;
	emu->page_ptr_table[page] = dmab.area;
	}
	return 0;

	__fail:
	/* release allocated pages */
	last_page = page - 1;
	for (page = first_page; page <= last_page; page++) {
	dmab.area = emu->page_ptr_table[page];
	dmab.addr = emu->page_addr_table[page];
	dmab.bytes = PAGE_SIZE;
	snd_dma_free_pages(&dmab);
	emu->page_addr_table[page] = 0;
	emu->page_ptr_table[page] = NULL;
	}

	return -ENOMEM;
	}

	/*
	* free pages
	*/
	static int synth_free_pages(struct snd_emu10k1 emu, struct snd_emu10k1_memblk blk)
	{
	int page, first_page, last_page;
	struct snd_dma_buffer dmab;

	get_single_page_range(emu->memhdr, blk, &first_page, &last_page);
	dmab.dev.type = SNDRV_DMA_TYPE_DEV;
	dmab.dev.dev = snd_dma_pci_data(emu->pci);
	for (page = first_page; page <= last_page; page++) {
	if (emu->page_ptr_table[page] == NULL)
	continue;
	dmab.area = emu->page_ptr_table[page];
	dmab.addr = emu->page_addr_table[page];
	dmab.bytes = PAGE_SIZE;
	snd_dma_free_pages(&dmab);
	emu->page_addr_table[page] = 0;
	emu->page_ptr_table[page] = NULL;
	}

	return 0;
	}

	/* calculate buffer pointer from offset address */
	static inline void offset_ptr(struct snd_emu10k1 emu, int page, int offset)
	{
	char *ptr;
	snd_assert(page >= 0 && page < emu->max_cache_pages, return NULL);
	ptr = emu->page_ptr_table[page];
	if (! ptr) {
	printk(KERN_ERR "emu10k1: access to NULL ptr: page = %d\n", page);
	return NULL;
	}
	ptr += offset & (PAGE_SIZE - 1);
	return (void*)ptr;
	}

	/*
	* bzero(blk + offset, size)
	*/
	int snd_emu10k1_synth_bzero(struct snd_emu10k1 emu, struct snd_util_memblk blk,
	int offset, int size)
	{
	int page, nextofs, end_offset, temp, temp1;
	void *ptr;
	struct snd_emu10k1_memblk p = (struct snd_emu10k1_memblk )blk;

	offset += blk->offset & (PAGE_SIZE - 1);
	end_offset = offset + size;
	page = get_aligned_page(offset);
	do {
	nextofs = aligned_page_offset(page + 1);
	temp = nextofs - offset;
	temp1 = end_offset - offset;
	if (temp1 < temp)
	temp = temp1;
	ptr = offset_ptr(emu, page + p->first_page, offset);
	if (ptr)
	memset(ptr, 0, temp);
	offset = nextofs;
	page++;
	} while (offset < end_offset);
	return 0;
	}

	/*
	* copy_from_user(blk + offset, data, size)
	*/
	int snd_emu10k1_synth_copy_from_user(struct snd_emu10k1 emu, struct snd_util_memblk blk,
	int offset, const char __user *data, int size)
	{
	int page, nextofs, end_offset, temp, temp1;
	void *ptr;
	struct snd_emu10k1_memblk p = (struct snd_emu10k1_memblk )blk;

	offset += blk->offset & (PAGE_SIZE - 1);
	end_offset = offset + size;
	page = get_aligned_page(offset);
	do {
	nextofs = aligned_page_offset(page + 1);
	temp = nextofs - offset;
	temp1 = end_offset - offset;
	if (temp1 < temp)
	temp = temp1;
	ptr = offset_ptr(emu, page + p->first_page, offset);
	if (ptr && copy_from_user(ptr, data, temp))
	return -EFAULT;
	offset = nextofs;
	data += temp;
	page++;
	} while (offset < end_offset);
	return 0;
	}