[PATCH 4/4] drivers/mtd: docg3 add protection against concurrency
Robert Jarzmik
robert.jarzmik at free.fr
Mon Mar 19 18:32:22 EDT 2012
As docg3 is intolerant against reentrancy, especially
because of its weird register access (ie. a register read is
performed by a first register write), each access to the
docg3 IO space must be locked.
Lock the IO space with a mutex, shared by all chips on the
same cascade, as they all share the same IO space.
Signed-off-by: Robert Jarzmik <robert.jarzmik at free.fr>
---
drivers/mtd/devices/docg3.c | 60 +++++++++++++++++++++++++++++++++++--------
drivers/mtd/devices/docg3.h | 2 +
2 files changed, 51 insertions(+), 11 deletions(-)
diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
index 03c9c99..6703b6c 100644
--- a/drivers/mtd/devices/docg3.c
+++ b/drivers/mtd/devices/docg3.c
@@ -80,6 +80,16 @@ static struct nand_ecclayout docg3_oobinfo = {
.oobavail = 8,
};
+static void cascade_lock(struct docg3 *docg3)
+{
+ mutex_lock(&docg3->cascade->lock);
+}
+
+static void cascade_unlock(struct docg3 *docg3)
+{
+ mutex_unlock(&docg3->cascade->lock);
+}
+
static inline u8 doc_readb(struct docg3 *docg3, u16 reg)
{
u8 val = readb(docg3->cascade->base + reg);
@@ -875,6 +885,7 @@ static int doc_read_oob(struct mtd_info *mtd, loff_t from,
ops->retlen = 0;
ret = 0;
skip = from % DOC_LAYOUT_PAGE_SIZE;
+ cascade_lock(docg3);
while (!ret && (len > 0 || ooblen > 0)) {
calc_block_sector(from - skip, &block0, &block1, &page, &ofs,
docg3->reliable);
@@ -882,7 +893,7 @@ static int doc_read_oob(struct mtd_info *mtd, loff_t from,
nboob = min_t(size_t, ooblen, (size_t)DOC_LAYOUT_OOB_SIZE);
ret = doc_read_page_prepare(docg3, block0, block1, page, ofs);
if (ret < 0)
- goto err;
+ goto out;
ret = doc_read_page_ecc_init(docg3, DOC_ECC_BCH_TOTAL_BYTES);
if (ret < 0)
goto err_in_read;
@@ -949,11 +960,12 @@ static int doc_read_oob(struct mtd_info *mtd, loff_t from,
skip = 0;
}
+out:
+ cascade_unlock(docg3);
return ret;
err_in_read:
doc_read_page_finish(docg3);
-err:
- return ret;
+ goto out;
}
/**
@@ -1193,7 +1205,6 @@ static int doc_erase(struct mtd_info *mtd, struct erase_info *info)
int block0, block1, page, ret, ofs = 0;
doc_dbg("doc_erase(from=%lld, len=%lld\n", info->addr, info->len);
- doc_set_device_id(docg3, docg3->device_id);
info->state = MTD_ERASE_PENDING;
calc_block_sector(info->addr + info->len, &block0, &block1, &page,
@@ -1205,6 +1216,8 @@ static int doc_erase(struct mtd_info *mtd, struct erase_info *info)
ret = 0;
calc_block_sector(info->addr, &block0, &block1, &page, &ofs,
docg3->reliable);
+ cascade_lock(docg3);
+ doc_set_device_id(docg3, docg3->device_id);
doc_set_reliable_mode(docg3);
for (len = info->len; !ret && len > 0; len -= mtd->erasesize) {
info->state = MTD_ERASING;
@@ -1212,6 +1225,7 @@ static int doc_erase(struct mtd_info *mtd, struct erase_info *info)
block0 += 2;
block1 += 2;
}
+ cascade_unlock(docg3);
if (ret)
goto reset_err;
@@ -1398,7 +1412,7 @@ static int doc_write_oob(struct mtd_info *mtd, loff_t ofs,
struct mtd_oob_ops *ops)
{
struct docg3 *docg3 = mtd->priv;
- int block0, block1, page, ret, pofs = 0, autoecc, oobdelta;
+ int ret, autoecc, oobdelta;
u8 *oobbuf = ops->oobbuf;
u8 *buf = ops->datbuf;
size_t len, ooblen;
@@ -1450,6 +1464,7 @@ static int doc_write_oob(struct mtd_info *mtd, loff_t ofs,
if (autoecc < 0)
return autoecc;
+ cascade_lock(docg3);
while (!ret && len > 0) {
memset(oob, 0, sizeof(oob));
if (ofs == docg3->oob_write_ofs)
@@ -1470,8 +1485,9 @@ static int doc_write_oob(struct mtd_info *mtd, loff_t ofs,
}
ops->retlen += DOC_LAYOUT_PAGE_SIZE;
}
-err:
+
doc_set_device_id(docg3, 0);
+ cascade_unlock(docg3);
return ret;
}
@@ -1528,9 +1544,11 @@ static ssize_t dps0_is_key_locked(struct device *dev,
struct docg3 *docg3 = sysfs_dev2docg3(dev, attr);
int dps0;
+ cascade_lock(docg3);
doc_set_device_id(docg3, docg3->device_id);
dps0 = doc_register_readb(docg3, DOC_DPS0_STATUS);
doc_set_device_id(docg3, 0);
+ cascade_unlock(docg3);
return sprintf(buf, "%d\n", !(dps0 & DOC_DPS_KEY_OK));
}
@@ -1541,9 +1559,11 @@ static ssize_t dps1_is_key_locked(struct device *dev,
struct docg3 *docg3 = sysfs_dev2docg3(dev, attr);
int dps1;
+ cascade_lock(docg3);
doc_set_device_id(docg3, docg3->device_id);
dps1 = doc_register_readb(docg3, DOC_DPS1_STATUS);
doc_set_device_id(docg3, 0);
+ cascade_unlock(docg3);
return sprintf(buf, "%d\n", !(dps1 & DOC_DPS_KEY_OK));
}
@@ -1558,10 +1578,12 @@ static ssize_t dps0_insert_key(struct device *dev,
if (count != DOC_LAYOUT_DPS_KEY_LENGTH)
return -EINVAL;
+ cascade_lock(docg3);
doc_set_device_id(docg3, docg3->device_id);
for (i = 0; i < DOC_LAYOUT_DPS_KEY_LENGTH; i++)
doc_writeb(docg3, buf[i], DOC_DPS0_KEY);
doc_set_device_id(docg3, 0);
+ cascade_unlock(docg3);
return count;
}
@@ -1575,10 +1597,12 @@ static ssize_t dps1_insert_key(struct device *dev,
if (count != DOC_LAYOUT_DPS_KEY_LENGTH)
return -EINVAL;
+ cascade_lock(docg3);
doc_set_device_id(docg3, docg3->device_id);
for (i = 0; i < DOC_LAYOUT_DPS_KEY_LENGTH; i++)
doc_writeb(docg3, buf[i], DOC_DPS1_KEY);
doc_set_device_id(docg3, 0);
+ cascade_unlock(docg3);
return count;
}
@@ -1633,7 +1657,11 @@ static int dbg_flashctrl_show(struct seq_file *s, void *p)
struct docg3 *docg3 = (struct docg3 *)s->private;
int pos = 0;
- u8 fctrl = doc_register_readb(docg3, DOC_FLASHCONTROL);
+ u8 fctrl;
+
+ cascade_lock(docg3);
+ fctrl = doc_register_readb(docg3, DOC_FLASHCONTROL);
+ cascade_unlock(docg3);
pos += seq_printf(s,
"FlashControl : 0x%02x (%s,CE# %s,%s,%s,flash %s)\n",
@@ -1651,9 +1679,12 @@ static int dbg_asicmode_show(struct seq_file *s, void *p)
{
struct docg3 *docg3 = (struct docg3 *)s->private;
- int pos = 0;
- int pctrl = doc_register_readb(docg3, DOC_ASICMODE);
- int mode = pctrl & 0x03;
+ int pos = 0, pctrl, mode;
+
+ cascade_lock(docg3);
+ pctrl = doc_register_readb(docg3, DOC_ASICMODE);
+ mode = pctrl & 0x03;
+ cascade_unlock(docg3);
pos += seq_printf(s,
"%04x : RAM_WE=%d,RSTIN_RESET=%d,BDETCT_RESET=%d,WRITE_ENABLE=%d,POWERDOWN=%d,MODE=%d%d (",
@@ -1685,7 +1716,11 @@ static int dbg_device_id_show(struct seq_file *s, void *p)
{
struct docg3 *docg3 = (struct docg3 *)s->private;
int pos = 0;
- int id = doc_register_readb(docg3, DOC_DEVICESELECT);
+ int id;
+
+ cascade_lock(docg3);
+ id = doc_register_readb(docg3, DOC_DEVICESELECT);
+ cascade_unlock(docg3);
pos += seq_printf(s, "DeviceId = %d\n", id);
return pos;
@@ -1698,6 +1733,7 @@ static int dbg_protection_show(struct seq_file *s, void *p)
int pos = 0;
int protect, dps0, dps0_low, dps0_high, dps1, dps1_low, dps1_high;
+ cascade_lock(docg3);
protect = doc_register_readb(docg3, DOC_PROTECTION);
dps0 = doc_register_readb(docg3, DOC_DPS0_STATUS);
dps0_low = doc_register_readw(docg3, DOC_DPS0_ADDRLOW);
@@ -1705,6 +1741,7 @@ static int dbg_protection_show(struct seq_file *s, void *p)
dps1 = doc_register_readb(docg3, DOC_DPS1_STATUS);
dps1_low = doc_register_readw(docg3, DOC_DPS1_ADDRLOW);
dps1_high = doc_register_readw(docg3, DOC_DPS1_ADDRHIGH);
+ cascade_unlock(docg3);
pos += seq_printf(s, "Protection = 0x%02x (",
protect);
@@ -2021,6 +2058,7 @@ static int __init docg3_probe(struct platform_device *pdev)
if (!cascade)
goto nomem1;
cascade->base = base;
+ mutex_init(&cascade->lock);
cascade->bch = init_bch(DOC_ECC_BCH_M, DOC_ECC_BCH_T,
DOC_ECC_BCH_PRIMPOLY);
if (!cascade->bch)
diff --git a/drivers/mtd/devices/docg3.h b/drivers/mtd/devices/docg3.h
index 642e606..19fb93f 100644
--- a/drivers/mtd/devices/docg3.h
+++ b/drivers/mtd/devices/docg3.h
@@ -273,11 +273,13 @@
* @floors: floors (ie. one physical docg3 chip is one floor)
* @base: IO space to access all chips in the cascade
* @bch: the BCH correcting control structure
+ * @lock: lock to protect docg3 IO space from concurrent accesses
*/
struct docg3_cascade {
struct mtd_info *floors[DOC_MAX_NBFLOORS];
void __iomem *base;
struct bch_control *bch;
+ struct mutex lock;
};
/**
--
1.7.5.4
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