Create a sysfs interface that allows a user to manage an inserted
cards lock state. The sysfs attribute "lock" will be added to the
device's sysfs directory. The following commands are supported:
"setpw" - Set the cards password
"clearpw" - Clear the cards password
"lock" - Lock the card
"unlock" - Unlock the card
"erase" - Force erase the card, clear the password and unlock it
Commands that require a password will request the password through
the kernels KEYS subsystem.
Signed-off-by: Al Cooper <alcoop...@gmail.com>
---
drivers/mmc/core/mmc.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 81 insertions(+)
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index f36c76f..8e94eb8 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -697,6 +697,84 @@ static int mmc_compare_ext_csds(struct mmc_card *card,
unsigned bus_width)
return err;
}
+#ifdef CONFIG_MMC_LOCK
+
+ssize_t mmc_lock_show(struct device *dev, struct device_attribute *att,
+ char *buf)
+{
+ struct mmc_card *card = mmc_dev_to_card(dev);
+
+ if (!mmc_card_lockable(card))
+ return sprintf(buf, "unsupported\n");
+ else
+ return sprintf(buf, "%slocked\n", mmc_card_locked(card) ?
+ "" : "un");
+}
+
+
+static struct lock_cmd {
+ const char *name;
+ int io_cmd;
+ int locked_required;
+ int need_pw;
+} lock_cmds[] = {
+ { "erase", MMC_LOCK_MODE_ERASE, true, false },
+ { "clrpw", MMC_LOCK_MODE_CLR_PWD, false, true },
+ { "setpw", MMC_LOCK_MODE_SET_PWD, false, true },
+ { "lock", MMC_LOCK_MODE_LOCK, false, true },
+ { "unlock", MMC_LOCK_MODE_UNLOCK, true, true },
+};
+
+/*
+ * implement MMC password functions: force erase, set password,
+ * clear password, lock and unlock.
+ */
+ssize_t mmc_lock_store(struct device *dev, struct device_attribute *att,
+ const char *data, size_t len)
+{
+ struct mmc_card *card = mmc_dev_to_card(dev);
+ int res = -EINVAL;
+ int x;
+ struct mmc_password password;
+
+ mmc_claim_host(card->host);
+ if (!mmc_card_lockable(card))
+ goto out;
+ for (x = 0; x < ARRAY_SIZE(lock_cmds); x++) {
+ if (sysfs_streq(data, lock_cmds[x].name))
+ break;
+ }
+ if (x >= ARRAY_SIZE(lock_cmds))
+ goto out;
+
+ if ((lock_cmds[x].locked_required && !mmc_card_locked(card)) ||
+ (!lock_cmds[x].locked_required && mmc_card_locked(card))) {
+ dev_warn(dev, "%s requires %slocked card\n",
+ lock_cmds[x].name,
+ lock_cmds[x].locked_required ? "" : "un");
+ goto out;
+ }
+ if (lock_cmds[x].need_pw) {
+ res = mmc_get_password(card, &password);
+ if (res)
+ goto out;
+ }
+ res = mmc_lock_unlock(card, &password, lock_cmds[x].io_cmd);
+out:
+ mmc_release_host(card->host);
+ if (res == 0)
+ return len;
+ else
+ return res;
+}
+
+static DEVICE_ATTR(lock, S_IWUSR | S_IRUGO,
+ mmc_lock_show, mmc_lock_store);
+
+
+#endif /* CONFIG_MMC_LOCK */
+
+
MMC_DEV_ATTR(cid, "%08x%08x%08x%08x\n", card->raw_cid[0], card->raw_cid[1],
card->raw_cid[2], card->raw_cid[3]);
MMC_DEV_ATTR(csd, "%08x%08x%08x%08x\n", card->raw_csd[0], card->raw_csd[1],
@@ -751,6 +829,9 @@ static struct attribute *mmc_std_attrs[] = {
&dev_attr_enhanced_area_size.attr,
&dev_attr_raw_rpmb_size_mult.attr,
&dev_attr_rel_sectors.attr,
+#ifdef CONFIG_MMC_LOCK
+ &dev_attr_lock.attr,
+#endif /* CONFIG_MMC_LOCK */
NULL,
};
ATTRIBUTE_GROUPS(mmc_std);
--
1.9.0.138.g2de3478
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