davinci_nand partition config handling

Update/bugfix partition config handling.  This removes some inlines in
the body of the driver, bugfixes cmdlinepart handling, bugfixes the
"no partitions" cases, and cleans up properly on driver removal.

Yes, these bugs are common in MTD drivers; I think the MTD framework
should eventually get help, maybe like this, to help un-obfuscate
drivers (which almost all have such #ifdeffery today).
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

drivers/mtd/nand/davinci_nand.c

@@ -53,6 +53,19 @@
 #include <asm/mach-types.h>
 #include <asm/mach/flash.h>
 
+
+#ifdef CONFIG_MTD_PARTITIONS
+static inline int mtd_has_partitions(void) { return 1; }
+#else
+static inline int mtd_has_partitions(void) { return 0; }
+#endif
+
+#ifdef CONFIG_MTD_CMDLINE_PARTS
+static inline int mtd_has_cmdlinepart(void) { return 1; }
+#else
+static inline int mtd_has_cmdlinepart(void) { return 0; }
+#endif
+
 #ifdef CONFIG_NAND_FLASH_HW_ECC
 #define DAVINCI_NAND_ECC_MODE NAND_ECC_HW3_512
 #else
@@ -67,6 +80,7 @@ struct davinci_nand_info {
 
 	struct device		*dev;
 	struct clk		*clk;
+	bool			partitioned;
 
 	void __iomem		*base;
 	void __iomem		*vaddr;
@@ -74,9 +88,6 @@ struct davinci_nand_info {
 
 #define to_davinci_nand(m) container_of(m, struct davinci_nand_info, mtd)
 
-#ifdef CONFIG_MTD_PARTITIONS
-const char *part_probes[] = { "cmdlinepart", NULL };
-#endif
 
 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
 
@@ -522,14 +533,8 @@ static int __init nand_davinci_probe(struct platform_device *pdev)
 	struct davinci_nand_info	*info;
 	struct resource			*res1;
 	struct resource			*res2;
-#ifdef CONFIG_MTD_CMDLINE_PARTS
-	struct mtd_partition		*mtd_parts = 0;
-	char				*master_name;
-	int				mtd_parts_nb = 0;
-#endif
 	void __iomem			*vaddr;
 	void __iomem			*base;
-
 	int				ret;
 	u32				rev;
 
@@ -624,24 +629,59 @@ static int __init nand_davinci_probe(struct platform_device *pdev)
 		goto err_scan;
 	}
 
-	/* Register the partitions */
-	add_mtd_partitions(&info->mtd, pdata->parts, pdata->nr_parts);
+	if (mtd_has_partitions()) {
+		struct mtd_partition	*mtd_parts = NULL;
+		int			mtd_parts_nb = 0;
 
-#ifdef CONFIG_MTD_CMDLINE_PARTS
-	/* Set info->mtd.name = 0 temporarily */
-	master_name		= info->mtd.name;
-	info->mtd.name		= (char *)0;
+		if (mtd_has_cmdlinepart()) {
+			static const char *probes[] __initconst =
+				{ "cmdlinepart", NULL };
 
-	/* info->mtd.name == 0, means: don't bother checking
-	   <mtd-id> */
-	mtd_parts_nb = parse_mtd_partitions(&info->mtd, part_probes,
-					    &mtd_parts, 0);
+			const char		*master_name;
 
-	/* Restore info->mtd.name */
-	info->mtd.name = master_name;
+			/* Set info->mtd.name = 0 temporarily */
+			master_name		= info->mtd.name;
+			info->mtd.name		= (char *)0;
 
-	add_mtd_partitions(&info->mtd, mtd_parts, mtd_parts_nb);
-#endif
+			/* info->mtd.name == 0, means: don't bother checking
+			   <mtd-id> */
+			mtd_parts_nb = parse_mtd_partitions(&info->mtd, probes,
+							    &mtd_parts, 0);
+
+			/* Restore info->mtd.name */
+			info->mtd.name = master_name;
+		}
+
+		if (mtd_parts_nb <= 0) {
+			mtd_parts = pdata->parts;
+			mtd_parts_nb = pdata->nr_parts;
+		}
+
+		/* Register any partitions */
+		if (mtd_parts_nb > 0) {
+			ret = add_mtd_partitions(&info->mtd,
+					mtd_parts, mtd_parts_nb);
+			if (ret == 0)
+				info->partitioned = true;
+		}
+
+	} else if (pdata->nr_parts) {
+		dev_warn(&pdev->dev, "ignoring %d default partitions on %s\n",
+				pdata->nr_parts, info->mtd.name);
+	}
+
+	/* If there's no partition info, just package the whole chip
+	 * as a single MTD device.
+	 *
+	 * NOTE:  When using the DM355 with large block NAND chips, don't
+	 * use this driver to change data the ROM Boot Loader (RBL) reads
+	 * from one of the first 24 blocks.  See DM355 errata for details.
+	 */
+	if (!info->partitioned)
+		ret = add_mtd_device(&info->mtd) ? -ENODEV : 0;
+
+	if (ret < 0)
+		goto err_scan;
 
 	rev = davinci_nand_readl(info, NRCSR_OFFSET);
 	dev_info(&pdev->dev, "controller rev. %d.%d\n",
@@ -668,6 +708,12 @@ err_pdata:
 static int __exit nand_davinci_remove(struct platform_device *pdev)
 {
 	struct davinci_nand_info *info = platform_get_drvdata(pdev);
+	int status;
+
+	if (mtd_has_partitions() && info->partitioned)
+		status = del_mtd_partitions(&info->mtd);
+	else
+		status = del_mtd_device(&info->mtd);
 
 	iounmap(info->base);
 	iounmap(info->vaddr);