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mmc: MMC boot partitions support.

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Allows device MMC boot partitions to be accessed. MMC partitions are
treated effectively as separate block devices on the same MMC card.

Signed-off-by: Andrei Warkentin <andreiw@motorola.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Andrei Warkentin 2011-04-11 18:10:25 -05:00 committed by Chris Ball
parent 1a258db6f3
commit 371a689f64
7 changed files with 311 additions and 48 deletions
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2
Documentation/mmc/00-INDEX
View File

@ -2,3 +2,5 @@
- this file
mmc-dev-attrs.txt
- info on SD and MMC device attributes
mmc-dev-parts.txt
- info on SD and MMC device partitions

10
Documentation/mmc/mmc-dev-attrs.txt
View File

@ -1,3 +1,13 @@
SD and MMC Block Device Attributes
==================================
These attributes are defined for the block devices associated with the
SD or MMC device.
The following attributes are read/write.
force_ro Enforce read-only access even if write protect switch is off.
SD and MMC Device Attributes
============================

27
Documentation/mmc/mmc-dev-parts.txt Normal file
View File

@ -0,0 +1,27 @@
SD and MMC Device Partitions
============================
Device partitions are additional logical block devices present on the
SD/MMC device.
As of this writing, MMC boot partitions as supported and exposed as
/dev/mmcblkXboot0 and /dev/mmcblkXboot1, where X is the index of the
parent /dev/mmcblkX.
MMC Boot Partitions
===================
Read and write access is provided to the two MMC boot partitions. Due to
the sensitive nature of the boot partition contents, which often store
a bootloader or bootloader configuration tables crucial to booting the
platform, write access is disabled by default to reduce the chance of
accidental bricking.
To enable write access to /dev/mmcblkXbootY, disable the forced read-only
access with:
echo 0 > /sys/block/mmcblkXbootY/force_ro
To re-enable read-only access:
echo 1 > /sys/block/mmcblkXbootY/force_ro

286
drivers/mmc/card/block.c
View File

@ -76,9 +76,19 @@ struct mmc_blk_data {
spinlock_t lock;
struct gendisk *disk;
struct mmc_queue queue;
struct list_head part;
unsigned int usage;
unsigned int read_only;
unsigned int part_type;
/*
* Only set in main mmc_blk_data associated
* with mmc_card with mmc_set_drvdata, and keeps
* track of the current selected device partition.
*/
unsigned int part_curr;
struct device_attribute force_ro;
};
static DEFINE_MUTEX(open_lock);
@ -101,17 +111,22 @@ static struct mmc_blk_data *mmc_blk_get(struct gendisk *disk)
return md;
}
static inline int mmc_get_devidx(struct gendisk *disk)
{
int devmaj = MAJOR(disk_devt(disk));
int devidx = MINOR(disk_devt(disk)) / perdev_minors;
if (!devmaj)
devidx = disk->first_minor / perdev_minors;
return devidx;
}
static void mmc_blk_put(struct mmc_blk_data *md)
{
mutex_lock(&open_lock);
md->usage--;
if (md->usage == 0) {
int devmaj = MAJOR(disk_devt(md->disk));
int devidx = MINOR(disk_devt(md->disk)) / perdev_minors;
if (!devmaj)
devidx = md->disk->first_minor / perdev_minors;
int devidx = mmc_get_devidx(md->disk);
blk_cleanup_queue(md->queue.queue);
__clear_bit(devidx, dev_use);
@ -122,6 +137,38 @@ static void mmc_blk_put(struct mmc_blk_data *md)
mutex_unlock(&open_lock);
}
static ssize_t force_ro_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
int ret;
struct mmc_blk_data *md = mmc_blk_get(dev_to_disk(dev));
ret = snprintf(buf, PAGE_SIZE, "%d",
get_disk_ro(dev_to_disk(dev)) ^
md->read_only);
mmc_blk_put(md);
return ret;
}
static ssize_t force_ro_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
int ret;
char *end;
struct mmc_blk_data *md = mmc_blk_get(dev_to_disk(dev));
unsigned long set = simple_strtoul(buf, &end, 0);
if (end == buf) {
ret = -EINVAL;
goto out;
}
set_disk_ro(dev_to_disk(dev), set || md->read_only);
ret = count;
out:
mmc_blk_put(md);
return ret;
}
static int mmc_blk_open(struct block_device *bdev, fmode_t mode)
{
struct mmc_blk_data *md = mmc_blk_get(bdev->bd_disk);
@ -176,6 +223,29 @@ struct mmc_blk_request {
struct mmc_data data;
};
static inline int mmc_blk_part_switch(struct mmc_card *card,
struct mmc_blk_data *md)
{
int ret;
struct mmc_blk_data *main_md = mmc_get_drvdata(card);
if (main_md->part_curr == md->part_type)
return 0;
if (mmc_card_mmc(card)) {
card->ext_csd.part_config &= ~EXT_CSD_PART_CONFIG_ACC_MASK;
card->ext_csd.part_config |= md->part_type;
ret = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
EXT_CSD_PART_CONFIG, card->ext_csd.part_config,
card->ext_csd.part_time);
if (ret)
return ret;
}
main_md->part_curr = md->part_type;
return 0;
}
static u32 mmc_sd_num_wr_blocks(struct mmc_card *card)
{
int err;
@ -620,6 +690,11 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
struct mmc_card *card = md->queue.card;
mmc_claim_host(card->host);
ret = mmc_blk_part_switch(card, md);
if (ret) {
ret = 0;
goto out;
}
if (req->cmd_flags & REQ_DISCARD) {
if (req->cmd_flags & REQ_SECURE)
@ -632,6 +707,7 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
ret = mmc_blk_issue_rw_rq(mq, req);
}
out:
mmc_release_host(card->host);
return ret;
}
@ -642,7 +718,11 @@ static inline int mmc_blk_readonly(struct mmc_card *card)
!(card->csd.cmdclass & CCC_BLOCK_WRITE);
}
static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card)
static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
struct device *parent,
sector_t size,
bool default_ro,
const char *subname)
{
struct mmc_blk_data *md;
int devidx, ret;
@ -658,7 +738,6 @@ static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card)
goto out;
}
/*
* Set the read-only status based on the supported commands
* and the write protect switch.
@ -672,6 +751,7 @@ static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card)
}
spin_lock_init(&md->lock);
INIT_LIST_HEAD(&md->part);
md->usage = 1;
ret = mmc_init_queue(&md->queue, card, &md->lock);
@ -686,8 +766,8 @@ static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card)
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);
md->disk->driverfs_dev = parent;
set_disk_ro(md->disk, md->read_only || default_ro);
if (REL_WRITES_SUPPORTED(card))
blk_queue_flush(md->queue.queue, REQ_FLUSH | REQ_FUA);
@ -703,25 +783,16 @@ static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card)
* messages to tell when the card is present.
*/
snprintf(md->disk->disk_name, sizeof(md->disk->disk_name),
"mmcblk%d", devidx);
if (subname)
snprintf(md->disk->disk_name, sizeof(md->disk->disk_name),
"mmcblk%d%s",
mmc_get_devidx(dev_to_disk(parent)), subname);
else
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));
}
set_capacity(md->disk, size);
return md;
err_putdisk:
@ -732,6 +803,79 @@ static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card)
return ERR_PTR(ret);
}
static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card)
{
sector_t size;
struct mmc_blk_data *md;
if (!mmc_card_sd(card) && mmc_card_blockaddr(card)) {
/*
* The EXT_CSD sector count is in number or 512 byte
* sectors.
*/
size = card->ext_csd.sectors;
} else {
/*
* The CSD capacity field is in units of read_blkbits.
* set_capacity takes units of 512 bytes.
*/
size = card->csd.capacity << (card->csd.read_blkbits - 9);
}
md = mmc_blk_alloc_req(card, &card->dev, size, false, NULL);
return md;
}
static int mmc_blk_alloc_part(struct mmc_card *card,
struct mmc_blk_data *md,
unsigned int part_type,
sector_t size,
bool default_ro,
const char *subname)
{
char cap_str[10];
struct mmc_blk_data *part_md;
part_md = mmc_blk_alloc_req(card, disk_to_dev(md->disk), size, default_ro,
subname);
if (IS_ERR(part_md))
return PTR_ERR(part_md);
part_md->part_type = part_type;
list_add(&part_md->part, &md->part);
string_get_size((u64)get_capacity(part_md->disk) << 9, STRING_UNITS_2,
cap_str, sizeof(cap_str));
printk(KERN_INFO "%s: %s %s partition %u %s\n",
part_md->disk->disk_name, mmc_card_id(card),
mmc_card_name(card), part_md->part_type, cap_str);
return 0;
}
static int mmc_blk_alloc_parts(struct mmc_card *card, struct mmc_blk_data *md)
{
int ret = 0;
if (!mmc_card_mmc(card))
return 0;
if (card->ext_csd.boot_size) {
ret = mmc_blk_alloc_part(card, md, EXT_CSD_PART_CONFIG_ACC_BOOT0,
card->ext_csd.boot_size >> 9,
true,
"boot0");
if (ret)
return ret;
ret = mmc_blk_alloc_part(card, md, EXT_CSD_PART_CONFIG_ACC_BOOT1,
card->ext_csd.boot_size >> 9,
true,
"boot1");
if (ret)
return ret;
}
return ret;
}
static int
mmc_blk_set_blksize(struct mmc_blk_data *md, struct mmc_card *card)
{
@ -750,9 +894,54 @@ mmc_blk_set_blksize(struct mmc_blk_data *md, struct mmc_card *card)
return 0;
}
static void mmc_blk_remove_req(struct mmc_blk_data *md)
{
if (md) {
if (md->disk->flags & GENHD_FL_UP) {
device_remove_file(disk_to_dev(md->disk), &md->force_ro);
/* Stop new requests from getting into the queue */
del_gendisk(md->disk);
}
/* Then flush out any already in there */
mmc_cleanup_queue(&md->queue);
mmc_blk_put(md);
}
}
static void mmc_blk_remove_parts(struct mmc_card *card,
struct mmc_blk_data *md)
{
struct list_head *pos, *q;
struct mmc_blk_data *part_md;
list_for_each_safe(pos, q, &md->part) {
part_md = list_entry(pos, struct mmc_blk_data, part);
list_del(pos);
mmc_blk_remove_req(part_md);
}
}
static int mmc_add_disk(struct mmc_blk_data *md)
{
int ret;
add_disk(md->disk);
md->force_ro.show = force_ro_show;
md->force_ro.store = force_ro_store;
md->force_ro.attr.name = "force_ro";
md->force_ro.attr.mode = S_IRUGO | S_IWUSR;
ret = device_create_file(disk_to_dev(md->disk), &md->force_ro);
if (ret)
del_gendisk(md->disk);
return ret;
}
static int mmc_blk_probe(struct mmc_card *card)
{
struct mmc_blk_data *md;
struct mmc_blk_data *md, *part_md;
int err;
char cap_str[10];
@ -776,14 +965,22 @@ static int mmc_blk_probe(struct mmc_card *card)
md->disk->disk_name, mmc_card_id(card), mmc_card_name(card),
cap_str, md->read_only ? "(ro)" : "");
if (mmc_blk_alloc_parts(card, md))
goto out;
mmc_set_drvdata(card, md);
add_disk(md->disk);
if (mmc_add_disk(md))
goto out;
list_for_each_entry(part_md, &md->part, part) {
if (mmc_add_disk(part_md))
goto out;
}
return 0;
out:
mmc_cleanup_queue(&md->queue);
mmc_blk_put(md);
mmc_blk_remove_parts(card, md);
mmc_blk_remove_req(md);
return err;
}
@ -791,36 +988,43 @@ static void mmc_blk_remove(struct mmc_card *card)
{
struct mmc_blk_data *md = mmc_get_drvdata(card);
if (md) {
/* Stop new requests from getting into the queue */
del_gendisk(md->disk);
/* Then flush out any already in there */
mmc_cleanup_queue(&md->queue);
mmc_blk_put(md);
}
mmc_blk_remove_parts(card, md);
mmc_blk_remove_req(md);
mmc_set_drvdata(card, NULL);
}
#ifdef CONFIG_PM
static int mmc_blk_suspend(struct mmc_card *card, pm_message_t state)
{
struct mmc_blk_data *part_md;
struct mmc_blk_data *md = mmc_get_drvdata(card);
if (md) {
mmc_queue_suspend(&md->queue);
list_for_each_entry(part_md, &md->part, part) {
mmc_queue_suspend(&part_md->queue);
}
}
return 0;
}
static int mmc_blk_resume(struct mmc_card *card)
{
struct mmc_blk_data *part_md;
struct mmc_blk_data *md = mmc_get_drvdata(card);
if (md) {
mmc_blk_set_blksize(md, card);
/*
* Resume involves the card going into idle state,
* so current partition is always the main one.
*/
md->part_curr = md->part_type;
mmc_queue_resume(&md->queue);
list_for_each_entry(part_md, &md->part, part) {
mmc_queue_resume(&part_md->queue);
}
}
return 0;
}

22
drivers/mmc/core/mmc.c
View File

@ -288,7 +288,10 @@ static int mmc_read_ext_csd(struct mmc_card *card)
if (card->ext_csd.rev >= 3) {
u8 sa_shift = ext_csd[EXT_CSD_S_A_TIMEOUT];
card->ext_csd.bootconfig = ext_csd[EXT_CSD_BOOT_CONFIG];
card->ext_csd.part_config = ext_csd[EXT_CSD_PART_CONFIG];
/* EXT_CSD value is in units of 10ms, but we store in ms */
card->ext_csd.part_time = 10 * ext_csd[EXT_CSD_PART_SWITCH_TIME];
/* Sleep / awake timeout in 100ns units */
if (sa_shift > 0 && sa_shift <= 0x17)
@ -302,6 +305,12 @@ static int mmc_read_ext_csd(struct mmc_card *card)
ext_csd[EXT_CSD_HC_ERASE_GRP_SIZE] << 10;
card->ext_csd.rel_sectors = ext_csd[EXT_CSD_REL_WR_SEC_C];
/*
* There are two boot regions of equal size, defined in
* multiples of 128K.
*/
card->ext_csd.boot_size = ext_csd[EXT_CSD_BOOT_MULT] << 17;
}
if (card->ext_csd.rev >= 4) {
@ -576,10 +585,13 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
/*
* Ensure eMMC user default partition is enabled
*/
if (card->ext_csd.bootconfig & 0x7) {
card->ext_csd.bootconfig &= ~0x7;
mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_BOOT_CONFIG,
card->ext_csd.bootconfig, 0);
if (card->ext_csd.part_config & EXT_CSD_PART_CONFIG_ACC_MASK) {
card->ext_csd.part_config &= ~EXT_CSD_PART_CONFIG_ACC_MASK;
err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_PART_CONFIG,
card->ext_csd.part_config,
card->ext_csd.part_time);
if (err && err != -EBADMSG)
goto free_card;
}
/*

4
include/linux/mmc/card.h
View File

@ -48,7 +48,8 @@ struct mmc_ext_csd {
u8 sec_feature_support;
u8 rel_sectors;
u8 rel_param;
u8 bootconfig;
u8 part_config;
unsigned int part_time; /* Units: ms */
unsigned int sa_timeout; /* Units: 100ns */
unsigned int hs_max_dtr;
unsigned int sectors;
@ -61,6 +62,7 @@ struct mmc_ext_csd {
bool enhanced_area_en; /* enable bit */
unsigned long long enhanced_area_offset; /* Units: Byte */
unsigned int enhanced_area_size; /* Units: KB */
unsigned int boot_size; /* in bytes */
};
struct sd_scr {

8
include/linux/mmc/mmc.h
View File

@ -257,19 +257,21 @@ struct _mmc_csd {
#define EXT_CSD_PARTITION_SUPPORT 160 /* RO */
#define EXT_CSD_WR_REL_PARAM 166 /* RO */
#define EXT_CSD_ERASE_GROUP_DEF 175 /* R/W */
#define EXT_CSD_BOOT_CONFIG 179 /* R/W */
#define EXT_CSD_PART_CONFIG 179 /* R/W */
#define EXT_CSD_ERASED_MEM_CONT 181 /* RO */
#define EXT_CSD_BUS_WIDTH 183 /* R/W */
#define EXT_CSD_HS_TIMING 185 /* R/W */
#define EXT_CSD_REV 192 /* RO */
#define EXT_CSD_STRUCTURE 194 /* RO */
#define EXT_CSD_CARD_TYPE 196 /* RO */
#define EXT_CSD_PART_SWITCH_TIME 199 /* RO */
#define EXT_CSD_SEC_CNT 212 /* RO, 4 bytes */
#define EXT_CSD_S_A_TIMEOUT 217 /* RO */
#define EXT_CSD_REL_WR_SEC_C 222 /* RO */
#define EXT_CSD_HC_WP_GRP_SIZE 221 /* RO */
#define EXT_CSD_ERASE_TIMEOUT_MULT 223 /* RO */
#define EXT_CSD_HC_ERASE_GRP_SIZE 224 /* RO */
#define EXT_CSD_BOOT_MULT 226 /* RO */
#define EXT_CSD_SEC_TRIM_MULT 229 /* RO */
#define EXT_CSD_SEC_ERASE_MULT 230 /* RO */
#define EXT_CSD_SEC_FEATURE_SUPPORT 231 /* RO */
@ -281,6 +283,10 @@ struct _mmc_csd {
#define EXT_CSD_WR_REL_PARAM_EN (1<<2)
#define EXT_CSD_PART_CONFIG_ACC_MASK (0x7)
#define EXT_CSD_PART_CONFIG_ACC_BOOT0 (0x1)
#define EXT_CSD_PART_CONFIG_ACC_BOOT1 (0x2)
#define EXT_CSD_CMD_SET_NORMAL (1<<0)
#define EXT_CSD_CMD_SET_SECURE (1<<1)
#define EXT_CSD_CMD_SET_CPSECURE (1<<2)