memory.c

linux2.6.16版本

/*
 *  Copyright (c) by Jaroslav Kysela <[e-mail]>
 *  Copyright (c) by Takashi Iwai <[e-mail]>
 *
 *  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;