10連休2日目は、TRIMコマンドについての勉強。
ソースコードは、Linux 2.6.39 baseで。
用語
/*
* Erase/trim/discard
*/
# define MMC_ERASE_ARG 0x00000000
# define MMC_SECURE_ERASE_ARG 0x80000000
# define MMC_TRIM_ARG 0x00000001
# define MMC_DISCARD_ARG 0x00000003
# define MMC_SECURE_TRIM1_ARG 0x80000001
# define MMC_SECURE_TRIM2_ARG 0x80008000
# define MMC_SECURE_ARGS 0x80000000
# define MMC_TRIM_ARGS 0x00008001
- SECURE_ERASE と、SECURE_TRIM については、 https://www.jedec.org/sites/default/files/Victor_Tsai.pdf の、Page 28-29を参照。
- DISCARDについては、SD 5.1から導入したらしい。 https://patchwork.kernel.org/patch/10830473/
ext3
ioctl.c
case FITRIM: {
struct super_block *sb = inode->i_sb;
struct fstrim_range range;
int ret = 0;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (copy_from_user(&range, (struct fstrim_range *)arg,
sizeof(range)))
return -EFAULT;
ret = ext3_trim_fs(sb, &range);
if (ret < 0)
return ret;
if (copy_to_user((struct fstrim_range *)arg, &range,
sizeof(range)))
return -EFAULT;
return 0;
}
balloc.c
/**
* ext3_trim_fs() -- trim ioctl handle function
* @sb: superblock for filesystem
* @start: First Byte to trim
* @len: number of Bytes to trim from start
* @minlen: minimum extent length in Bytes
*
* ext3_trim_fs goes through all allocation groups containing Bytes from
* start to start+len. For each such a group ext3_trim_all_free function
* is invoked to trim all free space.
*/
int ext3_trim_fs(struct super_block *sb, struct fstrim_range *range)
{
ext3_grpblk_t last_block, first_block, free_blocks;
unsigned long first_group, last_group;
unsigned long group, ngroups;
struct ext3_group_desc *gdp;
struct ext3_super_block *es = EXT3_SB(sb)->s_es;
uint64_t start, len, minlen, trimmed;
ext3_fsblk_t max_blks = le32_to_cpu(es->s_blocks_count);
int ret = 0;
start = (range->start >> sb->s_blocksize_bits) +
le32_to_cpu(es->s_first_data_block);
len = range->len >> sb->s_blocksize_bits;
minlen = range->minlen >> sb->s_blocksize_bits;
trimmed = 0;
if (unlikely(minlen > EXT3_BLOCKS_PER_GROUP(sb)))
return -EINVAL;
if (start >= max_blks)
goto out;
if (start + len > max_blks)
len = max_blks - start;
ngroups = EXT3_SB(sb)->s_groups_count;
smp_rmb();
/* Determine first and last group to examine based on start and len */
ext3_get_group_no_and_offset(sb, (ext3_fsblk_t) start,
&first_group, &first_block);
ext3_get_group_no_and_offset(sb, (ext3_fsblk_t) (start + len),
&last_group, &last_block);
last_group = (last_group > ngroups - 1) ? ngroups - 1 : last_group;
last_block = EXT3_BLOCKS_PER_GROUP(sb);
if (first_group > last_group)
return -EINVAL;
for (group = first_group; group <= last_group; group++) {
gdp = ext3_get_group_desc(sb, group, NULL);
if (!gdp)
break;
free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
if (free_blocks < minlen)
continue;
/*
* For all the groups except the last one, last block will
* always be EXT3_BLOCKS_PER_GROUP(sb), so we only need to
* change it for the last group in which case first_block +
* len < EXT3_BLOCKS_PER_GROUP(sb).
*/
if (first_block + len < EXT3_BLOCKS_PER_GROUP(sb))
last_block = first_block + len;
len -= last_block - first_block;
ret = ext3_trim_all_free(sb, group, first_block,
last_block, minlen);
if (ret < 0)
break;
trimmed += ret;
first_block = 0;
}
if (ret >= 0)
ret = 0;
out:
range->len = trimmed * sb->s_blocksize;
return ret;
}
balloc.c
/**
* ext3_trim_all_free -- function to trim all free space in alloc. group
* @sb: super block for file system
* @group: allocation group to trim
* @start: first group block to examine
* @max: last group block to examine
* @gdp: allocation group description structure
* @minblocks: minimum extent block count
*
* ext3_trim_all_free walks through group's block bitmap searching for free
* blocks. When the free block is found, it tries to allocate this block and
* consequent free block to get the biggest free extent possible, until it
* reaches any used block. Then issue a TRIM command on this extent and free
* the extent in the block bitmap. This is done until whole group is scanned.
*/
ext3_grpblk_t ext3_trim_all_free(struct super_block *sb, unsigned int group,
ext3_grpblk_t start, ext3_grpblk_t max,
ext3_grpblk_t minblocks)
{
handle_t *handle;
ext3_grpblk_t next, free_blocks, bit, freed, count = 0;
ext3_fsblk_t discard_block;
struct ext3_sb_info *sbi;
struct buffer_head *gdp_bh, *bitmap_bh = NULL;
struct ext3_group_desc *gdp;
int err = 0, ret = 0;
/*
* We will update one block bitmap, and one group descriptor
*/
handle = ext3_journal_start_sb(sb, 2);
if (IS_ERR(handle))
return PTR_ERR(handle);
bitmap_bh = read_block_bitmap(sb, group);
if (!bitmap_bh) {
err = -EIO;
goto err_out;
}
BUFFER_TRACE(bitmap_bh, "getting undo access");
err = ext3_journal_get_undo_access(handle, bitmap_bh);
if (err)
goto err_out;
gdp = ext3_get_group_desc(sb, group, &gdp_bh);
if (!gdp) {
err = -EIO;
goto err_out;
}
BUFFER_TRACE(gdp_bh, "get_write_access");
err = ext3_journal_get_write_access(handle, gdp_bh);
if (err)
goto err_out;
free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
sbi = EXT3_SB(sb);
/* Walk through the whole group */
while (start < max) {
start = bitmap_search_next_usable_block(start, bitmap_bh, max);
if (start < 0)
break;
next = start;
/*
* Allocate contiguous free extents by setting bits in the
* block bitmap
*/
while (next < max
&& claim_block(sb_bgl_lock(sbi, group),
next, bitmap_bh)) {
next++;
}
/* We did not claim any blocks */
if (next == start)
continue;
discard_block = (ext3_fsblk_t)start +
ext3_group_first_block_no(sb, group);
/* Update counters */
spin_lock(sb_bgl_lock(sbi, group));
le16_add_cpu(&gdp->bg_free_blocks_count, start - next);
spin_unlock(sb_bgl_lock(sbi, group));
percpu_counter_sub(&sbi->s_freeblocks_counter, next - start);
free_blocks -= next - start;
/* Do not issue a TRIM on extents smaller than minblocks */
if ((next - start) < minblocks)
goto free_extent;
/* Send the TRIM command down to the device */
err = sb_issue_discard(sb, discard_block, next - start,
GFP_NOFS, 0);
count += (next - start);
free_extent:
freed = 0;
/*
* Clear bits in the bitmap
*/
for (bit = start; bit < next; bit++) {
BUFFER_TRACE(bitmap_bh, "clear bit");
if (!ext3_clear_bit_atomic(sb_bgl_lock(sbi, group),
bit, bitmap_bh->b_data)) {
ext3_error(sb, __func__,
"bit already cleared for block "E3FSBLK,
(unsigned long)bit);
BUFFER_TRACE(bitmap_bh, "bit already cleared");
} else {
freed++;
}
}
/* Update couters */
spin_lock(sb_bgl_lock(sbi, group));
le16_add_cpu(&gdp->bg_free_blocks_count, freed);
spin_unlock(sb_bgl_lock(sbi, group));
percpu_counter_add(&sbi->s_freeblocks_counter, freed);
start = next;
if (err < 0) {
if (err != -EOPNOTSUPP)
ext3_warning(sb, __func__, "Discard command "
"returned error %d\n", err);
break;
}
if (fatal_signal_pending(current)) {
err = -ERESTARTSYS;
break;
}
cond_resched();
/* No more suitable extents */
if (free_blocks < minblocks)
break;
}
/* We dirtied the bitmap block */
BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
ret = ext3_journal_dirty_metadata(handle, bitmap_bh);
if (!err)
err = ret;
/* And the group descriptor block */
BUFFER_TRACE(gdp_bh, "dirtied group descriptor block");
ret = ext3_journal_dirty_metadata(handle, gdp_bh);
if (!err)
err = ret;
ext3_debug("trimmed %d blocks in the group %d\n",
count, group);
err_out:
if (err)
count = err;
ext3_journal_stop(handle);
brelse(bitmap_bh);
return count;
}
# block device
blkdev.h
static inline int sb_issue_discard(struct super_block *sb, sector_t block,
sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
{
return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
nr_blocks << (sb->s_blocksize_bits - 9),
gfp_mask, flags);
}
blk-lib.c
/**
* blkdev_issue_discard - queue a discard
* @bdev: blockdev to issue discard for
* @sector: start sector
* @nr_sects: number of sectors to discard
* @gfp_mask: memory allocation flags (for bio_alloc)
* @flags: BLKDEV_IFL_* flags to control behaviour
*
* Description:
* Issue a discard request for the sectors in question.
*/
int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
{
DECLARE_COMPLETION_ONSTACK(wait);
struct request_queue *q = bdev_get_queue(bdev);
int type = REQ_WRITE | REQ_DISCARD;
unsigned int max_discard_sectors;
struct bio *bio;
int ret = 0;
if (!q)
return -ENXIO;
if (!blk_queue_discard(q))
return -EOPNOTSUPP;
/*
* Ensure that max_discard_sectors is of the proper
* granularity
*/
max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);
if (q->limits.discard_granularity) {
unsigned int disc_sects = q->limits.discard_granularity >> 9;
max_discard_sectors &= ~(disc_sects - 1);
}
if (flags & BLKDEV_DISCARD_SECURE) {
if (!blk_queue_secdiscard(q))
return -EOPNOTSUPP;
type |= REQ_SECURE;
}
while (nr_sects && !ret) {
bio = bio_alloc(gfp_mask, 1);
if (!bio) {
ret = -ENOMEM;
break;
}
bio->bi_sector = sector;
bio->bi_end_io = blkdev_discard_end_io;
bio->bi_bdev = bdev;
bio->bi_private = &wait;
if (nr_sects > max_discard_sectors) {
bio->bi_size = max_discard_sectors << 9;
nr_sects -= max_discard_sectors;
sector += max_discard_sectors;
} else {
bio->bi_size = nr_sects << 9;
nr_sects = 0;
}
bio_get(bio);
submit_bio(type, bio);
wait_for_completion(&wait);
if (bio_flagged(bio, BIO_EOPNOTSUPP))
ret = -EOPNOTSUPP;
else if (!bio_flagged(bio, BIO_UPTODATE))
ret = -EIO;
bio_put(bio);
}
return ret;
}
EXPORT_SYMBOL(blkdev_issue_discard);
で、ここから先はここにまとまってる
ここまでのポイント。
- REQ_WRITE | REQ_DISCARD か、
- REQ_WRITE | REQ_DISCARD | REQ_SECURE で要求が来る。
mmc/card
block.c
module_init(mmc_blk_init);
module_exit(mmc_blk_exit);
static struct mmc_driver mmc_driver = {
.drv = {
.name = "mmcblk",
},
.probe = mmc_blk_probe,
.remove = mmc_blk_remove,
.suspend = mmc_blk_suspend,
.resume = mmc_blk_resume,
};
static int __init mmc_blk_init(void)
{
int res;
if (perdev_minors != CONFIG_MMC_BLOCK_MINORS)
pr_info("mmcblk: using %d minors per device\n", perdev_minors);
max_devices = 256 / perdev_minors;
res = register_blkdev(MMC_BLOCK_MAJOR, "mmc");
if (res)
goto out;
res = mmc_register_driver(&mmc_driver);
if (res)
goto out2;
return 0;
out2:
unregister_blkdev(MMC_BLOCK_MAJOR, "mmc");
out:
return res;
}
static int mmc_blk_probe(struct mmc_card *card)
{
struct mmc_blk_data *md;
int err;
char cap_str[10];
/*
* Check that the card supports the command class(es) we need.
*/
if (!(card->csd.cmdclass & CCC_BLOCK_READ))
return -ENODEV;
md = mmc_blk_alloc(card);
if (IS_ERR(md))
return PTR_ERR(md);
err = mmc_blk_set_blksize(md, card);
if (err)
goto out;
string_get_size((u64)get_capacity(md->disk) << 9, STRING_UNITS_2,
cap_str, sizeof(cap_str));
printk(KERN_INFO "%s: %s %s %s %s\n",
md->disk->disk_name, mmc_card_id(card), mmc_card_name(card),
cap_str, md->read_only ? "(ro)" : "");
mmc_set_drvdata(card, md);
add_disk(md->disk);
return 0;
out:
mmc_cleanup_queue(&md->queue);
mmc_blk_put(md);
return err;
}
static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card)
{
struct mmc_blk_data *md;
int devidx, ret;
devidx = find_first_zero_bit(dev_use, max_devices);
if (devidx >= max_devices)
return ERR_PTR(-ENOSPC);
__set_bit(devidx, dev_use);
md = kzalloc(sizeof(struct mmc_blk_data), GFP_KERNEL);
if (!md) {
ret = -ENOMEM;
goto out;
}
/*
* Set the read-only status based on the supported commands
* and the write protect switch.
*/
md->read_only = mmc_blk_readonly(card);
md->disk = alloc_disk(perdev_minors);
if (md->disk == NULL) {
ret = -ENOMEM;
goto err_kfree;
}
spin_lock_init(&md->lock);
md->usage = 1;
ret = mmc_init_queue(&md->queue, card, &md->lock);
if (ret)
goto err_putdisk;
md->queue.issue_fn = mmc_blk_issue_rq;
md->queue.data = md;
md->disk->major = MMC_BLOCK_MAJOR;
md->disk->first_minor = devidx * perdev_minors;
md->disk->fops = &mmc_bdops;
md->disk->private_data = md;
md->disk->queue = md->queue.queue;
md->disk->driverfs_dev = &card->dev;
set_disk_ro(md->disk, md->read_only);
/*
* As discussed on lkml, GENHD_FL_REMOVABLE should:
*
* - be set for removable media with permanent block devices
* - be unset for removable block devices with permanent media
*
* Since MMC block devices clearly fall under the second
* case, we do not set GENHD_FL_REMOVABLE. Userspace
* should use the block device creation/destruction hotplug
* messages to tell when the card is present.
*/
snprintf(md->disk->disk_name, sizeof(md->disk->disk_name),
"mmcblk%d", devidx);
blk_queue_logical_block_size(md->queue.queue, 512);
if (!mmc_card_sd(card) && mmc_card_blockaddr(card)) {
/*
* The EXT_CSD sector count is in number or 512 byte
* sectors.
*/
set_capacity(md->disk, card->ext_csd.sectors);
} else {
/*
* The CSD capacity field is in units of read_blkbits.
* set_capacity takes units of 512 bytes.
*/
set_capacity(md->disk,
card->csd.capacity << (card->csd.read_blkbits - 9));
}
return md;
err_putdisk:
put_disk(md->disk);
err_kfree:
kfree(md);
out:
return ERR_PTR(ret);
}
mmc_init_queue()
queue.c
/**
* mmc_init_queue - initialise a queue structure.
* @mq: mmc queue
* @card: mmc card to attach this queue
* @lock: queue lock
*
* Initialise a MMC card request queue.
*/
int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock)
{
struct mmc_host *host = card->host;
u64 limit = BLK_BOUNCE_HIGH;
int ret;
if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
limit = *mmc_dev(host)->dma_mask;
mq->card = card;
mq->queue = blk_init_queue(mmc_request, lock);
if (!mq->queue)
return -ENOMEM;
mq->queue->queuedata = mq;
mq->req = NULL;
blk_queue_prep_rq(mq->queue, mmc_prep_request);
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
if (mmc_can_erase(card)) {
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mq->queue);
mq->queue->limits.max_discard_sectors = UINT_MAX;
if (card->erased_byte == 0)
mq->queue->limits.discard_zeroes_data = 1;
if (!mmc_can_trim(card) && is_power_of_2(card->erase_size)) {
mq->queue->limits.discard_granularity =
card->erase_size << 9;
mq->queue->limits.discard_alignment =
card->erase_size << 9;
}
if (mmc_can_secure_erase_trim(card))
queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD,
mq->queue);
}
# ifdef CONFIG_MMC_BLOCK_BOUNCE
if (host->max_segs == 1) {
unsigned int bouncesz;
bouncesz = MMC_QUEUE_BOUNCESZ;
if (bouncesz > host->max_req_size)
bouncesz = host->max_req_size;
if (bouncesz > host->max_seg_size)
bouncesz = host->max_seg_size;
if (bouncesz > (host->max_blk_count * 512))
bouncesz = host->max_blk_count * 512;
if (bouncesz > 512) {
mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
if (!mq->bounce_buf) {
printk(KERN_WARNING "%s: unable to "
"allocate bounce buffer\n",
mmc_card_name(card));
}
}
if (mq->bounce_buf) {
blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
blk_queue_max_hw_sectors(mq->queue, bouncesz / 512);
blk_queue_max_segments(mq->queue, bouncesz / 512);
blk_queue_max_segment_size(mq->queue, bouncesz);
mq->sg = kmalloc(sizeof(struct scatterlist),
GFP_KERNEL);
if (!mq->sg) {
ret = -ENOMEM;
goto cleanup_queue;
}
sg_init_table(mq->sg, 1);
mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
bouncesz / 512, GFP_KERNEL);
if (!mq->bounce_sg) {
ret = -ENOMEM;
goto cleanup_queue;
}
sg_init_table(mq->bounce_sg, bouncesz / 512);
}
}
# endif
if (!mq->bounce_buf) {
blk_queue_bounce_limit(mq->queue, limit);
blk_queue_max_hw_sectors(mq->queue,
min(host->max_blk_count, host->max_req_size / 512));
blk_queue_max_segments(mq->queue, host->max_segs);
blk_queue_max_segment_size(mq->queue, host->max_seg_size);
mq->sg = kmalloc(sizeof(struct scatterlist) *
host->max_segs, GFP_KERNEL);
if (!mq->sg) {
ret = -ENOMEM;
goto cleanup_queue;
}
sg_init_table(mq->sg, host->max_segs);
}
sema_init(&mq->thread_sem, 1);
mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd/%d",
host->index);
if (IS_ERR(mq->thread)) {
ret = PTR_ERR(mq->thread);
goto free_bounce_sg;
}
return 0;
free_bounce_sg:
if (mq->bounce_sg)
kfree(mq->bounce_sg);
mq->bounce_sg = NULL;
cleanup_queue:
if (mq->sg)
kfree(mq->sg);
mq->sg = NULL;
if (mq->bounce_buf)
kfree(mq->bounce_buf);
mq->bounce_buf = NULL;
blk_cleanup_queue(mq->queue);
return ret;
}
static int mmc_queue_thread(void *d)
{
struct mmc_queue *mq = d;
struct request_queue *q = mq->queue;
current->flags |= PF_MEMALLOC;
down(&mq->thread_sem);
do {
struct request *req = NULL;
spin_lock_irq(q->queue_lock);
set_current_state(TASK_INTERRUPTIBLE);
req = blk_fetch_request(q);
mq->req = req;
spin_unlock_irq(q->queue_lock);
if (!req) {
if (kthread_should_stop()) {
set_current_state(TASK_RUNNING);
break;
}
up(&mq->thread_sem);
schedule();
down(&mq->thread_sem);
continue;
}
set_current_state(TASK_RUNNING);
mq->issue_fn(mq, req);
} while (1);
up(&mq->thread_sem);
return 0;
}
md->queue.issue_fn = mmc_blk_issue_rq;
mmc_queue->issue_fn(mq,req) が実行される
block.c
static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
{
if (req->cmd_flags & REQ_DISCARD) {
if (req->cmd_flags & REQ_SECURE)
return mmc_blk_issue_secdiscard_rq(mq, req);
else
return mmc_blk_issue_discard_rq(mq, req);
} else {
return mmc_blk_issue_rw_rq(mq, req);
}
}
static int mmc_blk_issue_discard_rq(struct mmc_queue *mq, struct request *req)
{
struct mmc_blk_data *md = mq->data;
struct mmc_card *card = md->queue.card;
unsigned int from, nr, arg;
int err = 0;
mmc_claim_host(card->host);
if (!mmc_can_erase(card)) {
err = -EOPNOTSUPP;
goto out;
}
from = blk_rq_pos(req);
nr = blk_rq_sectors(req);
if (mmc_can_trim(card))
arg = MMC_TRIM_ARG;
else
arg = MMC_ERASE_ARG;
err = mmc_erase(card, from, nr, arg);
out:
spin_lock_irq(&md->lock);
__blk_end_request(req, err, blk_rq_bytes(req));
spin_unlock_irq(&md->lock);
mmc_release_host(card->host);
return err ? 0 : 1;
}
static int mmc_blk_issue_secdiscard_rq(struct mmc_queue *mq,
struct request *req)
{
struct mmc_blk_data *md = mq->data;
struct mmc_card *card = md->queue.card;
unsigned int from, nr, arg;
int err = 0;
mmc_claim_host(card->host);
if (!mmc_can_secure_erase_trim(card)) {
err = -EOPNOTSUPP;
goto out;
}
from = blk_rq_pos(req);
nr = blk_rq_sectors(req);
if (mmc_can_trim(card) && !mmc_erase_group_aligned(card, from, nr))
arg = MMC_SECURE_TRIM1_ARG;
else
arg = MMC_SECURE_ERASE_ARG;
err = mmc_erase(card, from, nr, arg);
if (!err && arg == MMC_SECURE_TRIM1_ARG)
err = mmc_erase(card, from, nr, MMC_SECURE_TRIM2_ARG);
out:
spin_lock_irq(&md->lock);
__blk_end_request(req, err, blk_rq_bytes(req));
spin_unlock_irq(&md->lock);
mmc_release_host(card->host);
return err ? 0 : 1;
}
つまり、3パターンある。
- mmc_erase(card, from, nr, MMC_TRIM_ARG)
- mmc_erase(card, from, nr, MMC_ERASE_ARG)
- mmc_erase(card, from, nr, MMC_TRIM1_ARG) + mmc_erase(card, from, nr, MMC_TRIM2_ARG)
どれを使うのかは、下記による。
- mmc_can_trim()
- mmc_erase_group_aligned()
mmc/core
core.c
int mmc_can_trim(struct mmc_card *card)
{
if (card->ext_csd.sec_feature_support & EXT_CSD_SEC_GB_CL_EN)
return 1;
return 0;
}
/**
* mmc_erase - erase sectors.
* @card: card to erase
* @from: first sector to erase
* @nr: number of sectors to erase
* @arg: erase command argument (SD supports only %MMC_ERASE_ARG)
*
* Caller must claim host before calling this function.
*/
int mmc_erase(struct mmc_card *card, unsigned int from, unsigned int nr,
unsigned int arg)
{
unsigned int rem, to = from + nr;
if (!(card->host->caps & MMC_CAP_ERASE) ||
!(card->csd.cmdclass & CCC_ERASE))
return -EOPNOTSUPP;
if (!card->erase_size)
return -EOPNOTSUPP;
if (mmc_card_sd(card) && arg != MMC_ERASE_ARG)
return -EOPNOTSUPP;
if ((arg & MMC_SECURE_ARGS) &&
!(card->ext_csd.sec_feature_support & EXT_CSD_SEC_ER_EN))
return -EOPNOTSUPP;
if ((arg & MMC_TRIM_ARGS) &&
!(card->ext_csd.sec_feature_support & EXT_CSD_SEC_GB_CL_EN))
return -EOPNOTSUPP;
if (arg == MMC_SECURE_ERASE_ARG) {
if (from % card->erase_size || nr % card->erase_size)
return -EINVAL;
}
if (arg == MMC_ERASE_ARG) {
rem = from % card->erase_size;
if (rem) {
rem = card->erase_size - rem;
from += rem;
if (nr > rem)
nr -= rem;
else
return 0;
}
rem = nr % card->erase_size;
if (rem)
nr -= rem;
}
if (nr == 0)
return 0;
to = from + nr;
if (to <= from)
return -EINVAL;
/* 'from' and 'to' are inclusive */
to -= 1;
return mmc_do_erase(card, from, to, arg);
}
static int mmc_do_erase(struct mmc_card *card, unsigned int from,
unsigned int to, unsigned int arg)
{
struct mmc_command cmd;
unsigned int qty = 0;
int err;
/*
* qty is used to calculate the erase timeout which depends on how many
* erase groups (or allocation units in SD terminology) are affected.
* We count erasing part of an erase group as one erase group.
* For SD, the allocation units are always a power of 2. For MMC, the
* erase group size is almost certainly also power of 2, but it does not
* seem to insist on that in the JEDEC standard, so we fall back to
* division in that case. SD may not specify an allocation unit size,
* in which case the timeout is based on the number of write blocks.
*
* Note that the timeout for secure trim 2 will only be correct if the
* number of erase groups specified is the same as the total of all
* preceding secure trim 1 commands. Since the power may have been
* lost since the secure trim 1 commands occurred, it is generally
* impossible to calculate the secure trim 2 timeout correctly.
*/
if (card->erase_shift)
qty += ((to >> card->erase_shift) -
(from >> card->erase_shift)) + 1;
else if (mmc_card_sd(card))
qty += to - from + 1;
else
qty += ((to / card->erase_size) -
(from / card->erase_size)) + 1;
if (!mmc_card_blockaddr(card)) {
from <<= 9;
to <<= 9;
}
memset(&cmd, 0, sizeof(struct mmc_command));
if (mmc_card_sd(card))
cmd.opcode = SD_ERASE_WR_BLK_START;
else
cmd.opcode = MMC_ERASE_GROUP_START;
cmd.arg = from;
cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC;
err = mmc_wait_for_cmd(card->host, &cmd, 0);
if (err) {
printk(KERN_ERR "mmc_erase: group start error %d, "
"status %#x\n", err, cmd.resp[0]);
err = -EINVAL;
goto out;
}
memset(&cmd, 0, sizeof(struct mmc_command));
if (mmc_card_sd(card))
cmd.opcode = SD_ERASE_WR_BLK_END;
else
cmd.opcode = MMC_ERASE_GROUP_END;
cmd.arg = to;
cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC;
err = mmc_wait_for_cmd(card->host, &cmd, 0);
if (err) {
printk(KERN_ERR "mmc_erase: group end error %d, status %#x\n",
err, cmd.resp[0]);
err = -EINVAL;
goto out;
}
memset(&cmd, 0, sizeof(struct mmc_command));
cmd.opcode = MMC_ERASE;
cmd.arg = arg;
cmd.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
mmc_set_erase_timeout(card, &cmd, arg, qty);
err = mmc_wait_for_cmd(card->host, &cmd, 0);
if (err) {
printk(KERN_ERR "mmc_erase: erase error %d, status %#x\n",
err, cmd.resp[0]);
err = -EIO;
goto out;
}
if (mmc_host_is_spi(card->host))
goto out;
do {
memset(&cmd, 0, sizeof(struct mmc_command));
cmd.opcode = MMC_SEND_STATUS;
cmd.arg = card->rca << 16;
cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
/* Do not retry else we can't see errors */
err = mmc_wait_for_cmd(card->host, &cmd, 0);
if (err || (cmd.resp[0] & 0xFDF92000)) {
printk(KERN_ERR "error %d requesting status %#x\n",
err, cmd.resp[0]);
err = -EIO;
goto out;
}
} while (!(cmd.resp[0] & R1_READY_FOR_DATA) ||
R1_CURRENT_STATE(cmd.resp[0]) == 7);
out:
return err;
}
cmd.opcode = MMC_ERASE;
cmd.arg = arg;
err = mmc_wait_for_cmd(card->host, &cmd, 0);
/**
* mmc_wait_for_cmd - start a command and wait for completion
* @host: MMC host to start command
* @cmd: MMC command to start
* @retries: maximum number of retries
*
* Start a new MMC command for a host, and wait for the command
* to complete. Return any error that occurred while the command
* was executing. Do not attempt to parse the response.
*/
int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries)
{
struct mmc_request mrq;
WARN_ON(!host->claimed);
memset(&mrq, 0, sizeof(struct mmc_request));
memset(cmd->resp, 0, sizeof(cmd->resp));
cmd->retries = retries;
mrq.cmd = cmd;
cmd->data = NULL;
mmc_wait_for_req(host, &mrq);
return cmd->error;
}
/**
* mmc_wait_for_req - start a request and wait for completion
* @host: MMC host to start command
* @mrq: MMC request to start
*
* Start a new MMC custom command request for a host, and wait
* for the command to complete. Does not attempt to parse the
* response.
*/
void mmc_wait_for_req(struct mmc_host *host, struct mmc_request *mrq)
{
DECLARE_COMPLETION_ONSTACK(complete);
mrq->done_data = &complete;
mrq->done = mmc_wait_done;
mmc_start_request(host, mrq);
wait_for_completion(&complete);
}
static void
mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
{
# ifdef CONFIG_MMC_DEBUG
unsigned int i, sz;
struct scatterlist *sg;
# endif
pr_debug("%s: starting CMD%u arg %08x flags %08x\n",
mmc_hostname(host), mrq->cmd->opcode,
mrq->cmd->arg, mrq->cmd->flags);
if (mrq->data) {
pr_debug("%s: blksz %d blocks %d flags %08x "
"tsac %d ms nsac %d\n",
mmc_hostname(host), mrq->data->blksz,
mrq->data->blocks, mrq->data->flags,
mrq->data->timeout_ns / 1000000,
mrq->data->timeout_clks);
}
if (mrq->stop) {
pr_debug("%s: CMD%u arg %08x flags %08x\n",
mmc_hostname(host), mrq->stop->opcode,
mrq->stop->arg, mrq->stop->flags);
}
WARN_ON(!host->claimed);
mrq->cmd->error = 0;
mrq->cmd->mrq = mrq;
if (mrq->data) {
BUG_ON(mrq->data->blksz > host->max_blk_size);
BUG_ON(mrq->data->blocks > host->max_blk_count);
BUG_ON(mrq->data->blocks * mrq->data->blksz >
host->max_req_size);
# ifdef CONFIG_MMC_DEBUG
sz = 0;
for_each_sg(mrq->data->sg, sg, mrq->data->sg_len, i)
sz += sg->length;
BUG_ON(sz != mrq->data->blocks * mrq->data->blksz);
# endif
mrq->cmd->data = mrq->data;
mrq->data->error = 0;
mrq->data->mrq = mrq;
if (mrq->stop) {
mrq->data->stop = mrq->stop;
mrq->stop->error = 0;
mrq->stop->mrq = mrq;
}
}
mmc_host_clk_ungate(host);
led_trigger_event(host->led, LED_FULL);
host->ops->request(host, mrq);
}
ここでようやく、ホスト層に繋がる。
host->ops->request(host, mrq);
mmc/host
sdhci.c
static const struct mmc_host_ops sdhci_ops = {
.request = sdhci_request,
.set_ios = sdhci_set_ios,
.get_ro = sdhci_get_ro,
.enable_sdio_irq = sdhci_enable_sdio_irq,
};
/*****************************************************************************\
* *
* MMC callbacks *
* *
\*****************************************************************************/
static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
{
struct sdhci_host *host;
bool present;
unsigned long flags;
host = mmc_priv(mmc);
spin_lock_irqsave(&host->lock, flags);
WARN_ON(host->mrq != NULL);
# ifndef SDHCI_USE_LEDS_CLASS
sdhci_activate_led(host);
# endif
if (host->quirks & SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12) {
if (mrq->stop) {
mrq->data->stop = NULL;
mrq->stop = NULL;
}
}
host->mrq = mrq;
/* If polling, assume that the card is always present. */
if (host->quirks & SDHCI_QUIRK_BROKEN_CARD_DETECTION)
present = true;
else
present = sdhci_readl(host, SDHCI_PRESENT_STATE) &
SDHCI_CARD_PRESENT;
if (!present || host->flags & SDHCI_DEVICE_DEAD) {
host->mrq->cmd->error = -ENOMEDIUM;
tasklet_schedule(&host->finish_tasklet);
} else
sdhci_send_command(host, mrq->cmd);
mmiowb();
spin_unlock_irqrestore(&host->lock, flags);
}
static void sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
{
int flags;
u32 mask;
unsigned long timeout;
WARN_ON(host->cmd);
/* Wait max 10 ms */
timeout = 10;
mask = SDHCI_CMD_INHIBIT;
if ((cmd->data != NULL) || (cmd->flags & MMC_RSP_BUSY))
mask |= SDHCI_DATA_INHIBIT;
/* We shouldn't wait for data inihibit for stop commands, even
though they might use busy signaling */
if (host->mrq->data && (cmd == host->mrq->data->stop))
mask &= ~SDHCI_DATA_INHIBIT;
while (sdhci_readl(host, SDHCI_PRESENT_STATE) & mask) {
if (timeout == 0) {
printk(KERN_ERR "%s: Controller never released "
"inhibit bit(s).\n", mmc_hostname(host->mmc));
sdhci_dumpregs(host);
cmd->error = -EIO;
tasklet_schedule(&host->finish_tasklet);
return;
}
timeout--;
mdelay(1);
}
mod_timer(&host->timer, jiffies + 10 * HZ);
host->cmd = cmd;
sdhci_prepare_data(host, cmd->data);
sdhci_writel(host, cmd->arg, SDHCI_ARGUMENT);
sdhci_set_transfer_mode(host, cmd->data);
if ((cmd->flags & MMC_RSP_136) && (cmd->flags & MMC_RSP_BUSY)) {
printk(KERN_ERR "%s: Unsupported response type!\n",
mmc_hostname(host->mmc));
cmd->error = -EINVAL;
tasklet_schedule(&host->finish_tasklet);
return;
}
if (!(cmd->flags & MMC_RSP_PRESENT))
flags = SDHCI_CMD_RESP_NONE;
else if (cmd->flags & MMC_RSP_136)
flags = SDHCI_CMD_RESP_LONG;
else if (cmd->flags & MMC_RSP_BUSY)
flags = SDHCI_CMD_RESP_SHORT_BUSY;
else
flags = SDHCI_CMD_RESP_SHORT;
if (cmd->flags & MMC_RSP_CRC)
flags |= SDHCI_CMD_CRC;
if (cmd->flags & MMC_RSP_OPCODE)
flags |= SDHCI_CMD_INDEX;
if (cmd->data)
flags |= SDHCI_CMD_DATA;
sdhci_writew(host, SDHCI_MAKE_CMD(cmd->opcode, flags), SDHCI_COMMAND);
}
sdhci.h
struct sdhci_ops {
# ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS
u32 (*read_l)(struct sdhci_host *host, int reg);
u16 (*read_w)(struct sdhci_host *host, int reg);
u8 (*read_b)(struct sdhci_host *host, int reg);
void (*write_l)(struct sdhci_host *host, u32 val, int reg);
void (*write_w)(struct sdhci_host *host, u16 val, int reg);
void (*write_b)(struct sdhci_host *host, u8 val, int reg);
# endif
void (*set_clock)(struct sdhci_host *host, unsigned int clock);
int (*enable_dma)(struct sdhci_host *host);
unsigned int (*get_max_clock)(struct sdhci_host *host);
unsigned int (*get_min_clock)(struct sdhci_host *host);
unsigned int (*get_timeout_clock)(struct sdhci_host *host);
int (*platform_8bit_width)(struct sdhci_host *host,
int width);
void (*platform_send_init_74_clocks)(struct sdhci_host *host,
u8 power_mode);
unsigned int (*get_ro)(struct sdhci_host *host);
};
static inline void sdhci_writew(struct sdhci_host *host, u16 val, int reg)
{
if (unlikely(host->ops->write_w))
host->ops->write_w(host, val, reg);
else
writew(val, host->ioaddr + reg);
}
まとめ
・・・ていう流れで！！TRIMコマンドは実行されますと！！めでたしめでたし（調べたかったことはこれでOK)