[MTD] NAND: Check command timeout

Check timeout while we wait for the command to finish. No worry about a
false result. This prevents deadlocking when detecting an unknown number
of chips and is useful for removable media too.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 26 insertions, 11 deletions

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index acd5ec193ff1..4d7c916c74fc 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -59,7 +59,7 @@
  *      The AG-AND chips have nice features for speed improvement,
  *      which are not supported yet. Read / program 4 pages in one go.
  *
- * $Id: nand_base.c,v 1.133 2005/02/16 09:39:35 gleixner Exp $
+ * $Id: nand_base.c,v 1.134 2005/02/22 21:56:46 gleixner Exp $
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -509,6 +509,22 @@ static int nand_block_checkbad (struct mtd_info *mtd, loff_t ofs, int getchip, i
         return nand_isbad_bbt (mtd, ofs, allowbbt);
 }
 
+/* 
+ * Wait for the ready pin, after a command
+ * The timeout is catched later.
+ */
+static void nand_wait_ready(struct mtd_info *mtd)
+{
+        struct nand_chip *this = mtd->priv;
+        unsigned long   timeo = jiffies + 2;
+
+        /* wait until command is processed or timeout occures */
+        do {
+                if (this->dev_ready(mtd))
+                        return;
+        } while (time_before(jiffies, timeo));  
+}
+
 /**
  * nand_command - [DEFAULT] Send command to NAND device
  * @mtd:        MTD device structure
@@ -604,12 +620,11 @@ static void nand_command (struct mtd_info *mtd, unsigned command, int column, in
                         return;
                 }       
         }
-        
         /* Apply this short delay always to ensure that we do wait tWB in
          * any case on any machine. */
         ndelay (100);
-        /* wait until command is processed */
-        while (!this->dev_ready(mtd));
+
+        nand_wait_ready(mtd);
 }
 
 /**
@@ -720,12 +735,12 @@ static void nand_command_lp (struct mtd_info *mtd, unsigned command, int column,
                         return;
                 }       
         }
-        
+
         /* Apply this short delay always to ensure that we do wait tWB in
          * any case on any machine. */
         ndelay (100);
-        /* wait until command is processed */
-        while (!this->dev_ready(mtd));
+
+        nand_wait_ready(mtd);
 }
 
 /**
@@ -1011,7 +1026,7 @@ static int nand_verify_pages (struct mtd_info *mtd, struct nand_chip *this, int
                 if (!this->dev_ready) 
                         udelay (this->chip_delay);
                 else
-                        while (!this->dev_ready(mtd));  
+                        nand_wait_ready(mtd);
 
                 /* All done, return happy */
                 if (!numpages)
@@ -1302,7 +1317,7 @@ int nand_do_read_ecc (struct mtd_info *mtd, loff_t from, size_t len,
                 if (!this->dev_ready) 
                         udelay (this->chip_delay);
                 else
-                        while (!this->dev_ready(mtd));  
+                        nand_wait_ready(mtd);
                         
                 if (read == len)
                         break;  
@@ -1401,7 +1416,7 @@ static int nand_read_oob (struct mtd_info *mtd, loff_t from, size_t len, size_t
                 if (!this->dev_ready) 
                         udelay (this->chip_delay);
                 else
-                        while (!this->dev_ready(mtd));  
+                        nand_wait_ready(mtd);
 
                 /* Read more ? */
                 if (i < len) {
@@ -1481,7 +1496,7 @@ int nand_read_raw (struct mtd_info *mtd, uint8_t *buf, loff_t from, size_t len,
                 if (!this->dev_ready) 
                         udelay (this->chip_delay);
                 else
-                        while (!this->dev_ready(mtd));  
+                        nand_wait_ready(mtd);
                         
                 /* Check, if the chip supports auto page increment */ 
                 if (!NAND_CANAUTOINCR(this) || !(page & blockcheck))