mtd: docg3 add protection against concurrency

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@free.fr>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
index 935d4c6e9321e728340af2a0688a3b3deef84224..8272c02668d6ebccf54ad75b71da07158fd617be 100644 (file)
--- a/drivers/mtd/devices/docg3.c
+++ b/drivers/mtd/devices/docg3.c
@@ -875,6 +875,7 @@ static int doc_read_oob(struct mtd_info *mtd, loff_t from,
        ops->retlen = 0;
        ret = 0;
        skip = from % DOC_LAYOUT_PAGE_SIZE;
+       mutex_lock(&docg3->cascade->lock);
        while (!ret && (len > 0 || ooblen > 0)) {
                calc_block_sector(from - skip, &block0, &block1, &page, &ofs,
                        docg3->reliable);
@@ -882,7 +883,7 @@ 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;
@@ -950,11 +951,12 @@ static int doc_read_oob(struct mtd_info *mtd, loff_t from,
                skip = 0;
        }
 
+out:
+       mutex_unlock(&docg3->cascade->lock);
        return ret;
 err_in_read:
        doc_read_page_finish(docg3);
-err:
-       return ret;
+       goto out;
 }
 
 /**
@@ -1194,7 +1196,6 @@ 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,
@@ -1206,6 +1207,8 @@ 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);
+       mutex_lock(&docg3->cascade->lock);
+       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;
@@ -1213,6 +1216,7 @@ static int doc_erase(struct mtd_info *mtd, struct erase_info *info)
                block0 += 2;
                block1 += 2;
        }
+       mutex_unlock(&docg3->cascade->lock);
 
        if (ret)
                goto reset_err;
@@ -1399,7 +1403,7 @@ 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;
@@ -1451,6 +1455,7 @@ static int doc_write_oob(struct mtd_info *mtd, loff_t ofs,
        if (autoecc < 0)
                return autoecc;
 
+       mutex_lock(&docg3->cascade->lock);
        while (!ret && len > 0) {
                memset(oob, 0, sizeof(oob));
                if (ofs == docg3->oob_write_ofs)
@@ -1471,8 +1476,9 @@ 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);
+       mutex_unlock(&docg3->cascade->lock);
        return ret;
 }
 
@@ -1529,9 +1535,11 @@ static ssize_t dps0_is_key_locked(struct device *dev,
        struct docg3 *docg3 = sysfs_dev2docg3(dev, attr);
        int dps0;
 
+       mutex_lock(&docg3->cascade->lock);
        doc_set_device_id(docg3, docg3->device_id);
        dps0 = doc_register_readb(docg3, DOC_DPS0_STATUS);
        doc_set_device_id(docg3, 0);
+       mutex_unlock(&docg3->cascade->lock);
 
        return sprintf(buf, "%d\n", !(dps0 & DOC_DPS_KEY_OK));
 }
@@ -1542,9 +1550,11 @@ static ssize_t dps1_is_key_locked(struct device *dev,
        struct docg3 *docg3 = sysfs_dev2docg3(dev, attr);
        int dps1;
 
+       mutex_lock(&docg3->cascade->lock);
        doc_set_device_id(docg3, docg3->device_id);
        dps1 = doc_register_readb(docg3, DOC_DPS1_STATUS);
        doc_set_device_id(docg3, 0);
+       mutex_unlock(&docg3->cascade->lock);
 
        return sprintf(buf, "%d\n", !(dps1 & DOC_DPS_KEY_OK));
 }
@@ -1559,10 +1569,12 @@ static ssize_t dps0_insert_key(struct device *dev,
        if (count != DOC_LAYOUT_DPS_KEY_LENGTH)
                return -EINVAL;
 
+       mutex_lock(&docg3->cascade->lock);
        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);
+       mutex_unlock(&docg3->cascade->lock);
        return count;
 }
 
@@ -1576,10 +1588,12 @@ static ssize_t dps1_insert_key(struct device *dev,
        if (count != DOC_LAYOUT_DPS_KEY_LENGTH)
                return -EINVAL;
 
+       mutex_lock(&docg3->cascade->lock);
        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);
+       mutex_unlock(&docg3->cascade->lock);
        return count;
 }
 
@@ -1634,7 +1648,11 @@ 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;
+
+       mutex_lock(&docg3->cascade->lock);
+       fctrl = doc_register_readb(docg3, DOC_FLASHCONTROL);
+       mutex_unlock(&docg3->cascade->lock);
 
        pos += seq_printf(s,
                 "FlashControl : 0x%02x (%s,CE# %s,%s,%s,flash %s)\n",
@@ -1652,9 +1670,12 @@ 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;
+
+       mutex_lock(&docg3->cascade->lock);
+       pctrl = doc_register_readb(docg3, DOC_ASICMODE);
+       mode = pctrl & 0x03;
+       mutex_unlock(&docg3->cascade->lock);
 
        pos += seq_printf(s,
                         "%04x : RAM_WE=%d,RSTIN_RESET=%d,BDETCT_RESET=%d,WRITE_ENABLE=%d,POWERDOWN=%d,MODE=%d%d (",
@@ -1686,7 +1707,11 @@ 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;
+
+       mutex_lock(&docg3->cascade->lock);
+       id = doc_register_readb(docg3, DOC_DEVICESELECT);
+       mutex_unlock(&docg3->cascade->lock);
 
        pos += seq_printf(s, "DeviceId = %d\n", id);
        return pos;
@@ -1699,6 +1724,7 @@ 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;
 
+       mutex_lock(&docg3->cascade->lock);
        protect = doc_register_readb(docg3, DOC_PROTECTION);
        dps0 = doc_register_readb(docg3, DOC_DPS0_STATUS);
        dps0_low = doc_register_readw(docg3, DOC_DPS0_ADDRLOW);
@@ -1706,6 +1732,7 @@ 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);
+       mutex_unlock(&docg3->cascade->lock);
 
        pos += seq_printf(s, "Protection = 0x%02x (",
                         protect);
@@ -2022,6 +2049,7 @@ 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 642e60667cfd183d1fa2d0835b95618ca371e2ef..19fb93f96a3a4eca50f4f8b6bb01728b48bb064f 100644 (file)
--- 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;
 };
 
 /**