mtd: rawnand: Add support for manufacturer specific suspend/resume operation

Patch nand_suspend() & nand_resume() to let manufacturers overwrite
suspend/resume operations.
Signed-off-by: NMason Yang <masonccyang@mxic.com.tw>
Reviewed-by: NMiquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: NMiquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/1584517348-14486-2-git-send-email-masonccyang@mxic.com.tw

drivers/mtd/nand/raw/nand_base.c

@@ -4326,16 +4326,22 @@ static int nand_block_markbad(struct mtd_info *mtd, loff_t ofs)
 /**
  * nand_suspend - [MTD Interface] Suspend the NAND flash
  * @mtd: MTD device structure
+ *
+ * Returns 0 for success or negative error code otherwise.
  */
 static int nand_suspend(struct mtd_info *mtd)
 {
 	struct nand_chip *chip = mtd_to_nand(mtd);
+	int ret = 0;
 
 	mutex_lock(&chip->lock);
-	chip->suspended = 1;
+	if (chip->suspend)
+		ret = chip->suspend(chip);
+	if (!ret)
+		chip->suspended = 1;
 	mutex_unlock(&chip->lock);
 
-	return 0;
+	return ret;
 }
 
 /**
@@ -4347,11 +4353,14 @@ static void nand_resume(struct mtd_info *mtd)
 	struct nand_chip *chip = mtd_to_nand(mtd);
 
 	mutex_lock(&chip->lock);
-	if (chip->suspended)
+	if (chip->suspended) {
+		if (chip->resume)
+			chip->resume(chip);
 		chip->suspended = 0;
-	else
+	} else {
 		pr_err("%s called for a chip which is not in suspended state\n",
 			__func__);
+	}
 	mutex_unlock(&chip->lock);
 }
 

include/linux/mtd/rawnand.h

@@ -1064,6 +1064,8 @@ struct nand_legacy {
  * @lock:		lock protecting the suspended field. Also used to
  *			serialize accesses to the NAND device.
  * @suspended:		set to 1 when the device is suspended, 0 when it's not.
+ * @suspend:		[REPLACEABLE] specific NAND device suspend operation
+ * @resume:		[REPLACEABLE] specific NAND device resume operation
  * @bbt:		[INTERN] bad block table pointer
  * @bbt_td:		[REPLACEABLE] bad block table descriptor for flash
  *			lookup.
@@ -1119,6 +1121,8 @@ struct nand_chip {
 
 	struct mutex lock;
 	unsigned int suspended : 1;
+	int (*suspend)(struct nand_chip *chip);
+	void (*resume)(struct nand_chip *chip);
 
 	uint8_t *oob_poi;
 	struct nand_controller *controller;