[MTD NAND] Split nand_scan() into two parts; allow board driver to intervene

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

drivers/mtd/nand/nand_base.c

@@ -2289,40 +2289,22 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
 	return type;
 }
 
-/* module_text_address() isn't exported, and it's mostly a pointless
-   test if this is a module _anyway_ -- they'd have to try _really_ hard
-   to call us from in-kernel code if the core NAND support is modular. */
-#ifdef MODULE
-#define caller_is_module() (1)
-#else
-#define caller_is_module() \
-	module_text_address((unsigned long)__builtin_return_address(0))
-#endif
-
 /**
- * nand_scan - [NAND Interface] Scan for the NAND device
+ * nand_scan_ident - [NAND Interface] Scan for the NAND device
- * @mtd:	MTD device structure
+ * @mtd:	     MTD device structure
- * @maxchips:	Number of chips to scan for
+ * @maxchips:	     Number of chips to scan for
  *
- * This fills out all the uninitialized function pointers
+ * This is the first phase of the normal nand_scan() function. It
- * with the defaults.
+ * reads the flash ID and sets up MTD fields accordingly.
- * The flash ID is read and the mtd/chip structures are
- * filled with the appropriate values.
- * The mtd->owner field must be set to the module of the caller
  *
+ * The mtd->owner field must be set to the module of the caller.
  */
-int nand_scan(struct mtd_info *mtd, int maxchips)
+int nand_scan_ident(struct mtd_info *mtd, int maxchips)
 {
 	int i, busw, nand_maf_id;
 	struct nand_chip *chip = mtd->priv;
 	struct nand_flash_dev *type;
 
-	/* Many callers got this wrong, so check for it for a while... */
-	if (!mtd->owner && caller_is_module()) {
-		printk(KERN_CRIT "nand_scan() called with NULL mtd->owner!\n");
-		BUG();
-	}
-
 	/* Get buswidth to select the correct functions */
 	busw = chip->options & NAND_BUSWIDTH_16;
 	/* Set the default functions */
@@ -2354,6 +2336,24 @@ int nand_scan(struct mtd_info *mtd, int maxchips)
 	chip->numchips = i;
 	mtd->size = i * chip->chipsize;
 
+	return 0;
+}
+
+
+/**
+ * nand_scan_tail - [NAND Interface] Scan for the NAND device
+ * @mtd:	    MTD device structure
+ * @maxchips:	    Number of chips to scan for
+ *
+ * This is the second phase of the normal nand_scan() function. It
+ * fills out all the uninitialized function pointers with the defaults
+ * and scans for a bad block table if appropriate.
+ */
+int nand_scan_tail(struct mtd_info *mtd)
+{
+	int i;
+	struct nand_chip *chip = mtd->priv;
+
 	/* Preset the internal oob write buffer */
 	memset(chip->buffers.oobwbuf, 0xff, mtd->oobsize);
 
@@ -2504,6 +2504,44 @@ int nand_scan(struct mtd_info *mtd, int maxchips)
 	return chip->scan_bbt(mtd);
 }
 
+/* module_text_address() isn't exported, and it's mostly a pointless
+   test if this is a module _anyway_ -- they'd have to try _really_ hard
+   to call us from in-kernel code if the core NAND support is modular. */
+#ifdef MODULE
+#define caller_is_module() (1)
+#else
+#define caller_is_module() \
+	module_text_address((unsigned long)__builtin_return_address(0))
+#endif
+
+/**
+ * nand_scan - [NAND Interface] Scan for the NAND device
+ * @mtd:	MTD device structure
+ * @maxchips:	Number of chips to scan for
+ *
+ * This fills out all the uninitialized function pointers
+ * with the defaults.
+ * The flash ID is read and the mtd/chip structures are
+ * filled with the appropriate values.
+ * The mtd->owner field must be set to the module of the caller
+ *
+ */
+int nand_scan(struct mtd_info *mtd, int maxchips)
+{
+	int ret;
+
+	/* Many callers got this wrong, so check for it for a while... */
+	if (!mtd->owner && caller_is_module()) {
+		printk(KERN_CRIT "nand_scan() called with NULL mtd->owner!\n");
+		BUG();
+	}
+
+	ret = nand_scan_ident(mtd, maxchips);
+	if (!ret)
+		ret = nand_scan_tail(mtd);
+	return ret;
+}
+
 /**
  * nand_release - [NAND Interface] Free resources held by the NAND device
  * @mtd:	MTD device structure
@@ -2524,6 +2562,8 @@ void nand_release(struct mtd_info *mtd)
 }
 
 EXPORT_SYMBOL_GPL(nand_scan);
+EXPORT_SYMBOL_GPL(nand_scan_ident);
+EXPORT_SYMBOL_GPL(nand_scan_tail);
 EXPORT_SYMBOL_GPL(nand_release);
 
 static int __init nand_base_init(void)

include/linux/mtd/nand.h

@@ -27,6 +27,11 @@
 struct mtd_info;
 /* Scan and identify a NAND device */
 extern int nand_scan (struct mtd_info *mtd, int max_chips);
+/* Separate phases of nand_scan(), allowing board driver to intervene
+ * and override command or ECC setup according to flash type */
+extern int nand_scan_ident(struct mtd_info *mtd, int max_chips);
+extern int nand_scan_tail(struct mtd_info *mtd);
+
 /* Free resources held by the NAND device */
 extern void nand_release (struct mtd_info *mtd);