mtd: nand: Add a NAND page I/O request type

Use an enum to differentiate the type of I/O (reading or writing a
page). Also update the request iterator.
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://lore.kernel.org/linux-mtd/20200827085208.16276-5-miquel.raynal@bootlin.com

drivers/mtd/nand/spi/core.c

@@ -497,7 +497,7 @@ static int spinand_mtd_read(struct mtd_info *mtd, loff_t from,
 
 	mutex_lock(&spinand->lock);
 
-	nanddev_io_for_each_page(nand, from, ops, &iter) {
+	nanddev_io_for_each_page(nand, NAND_PAGE_READ, from, ops, &iter) {
 		ret = spinand_select_target(spinand, iter.req.pos.target);
 		if (ret)
 			break;
@@ -545,7 +545,7 @@ static int spinand_mtd_write(struct mtd_info *mtd, loff_t to,
 
 	mutex_lock(&spinand->lock);
 
-	nanddev_io_for_each_page(nand, to, ops, &iter) {
+	nanddev_io_for_each_page(nand, NAND_PAGE_WRITE, to, ops, &iter) {
 		ret = spinand_select_target(spinand, iter.req.pos.target);
 		if (ret)
 			break;

include/linux/mtd/nand.h

@@ -82,8 +82,19 @@ struct nand_pos {
 	unsigned int page;
 };
 
+/**
+ * enum nand_page_io_req_type - Direction of an I/O request
+ * @NAND_PAGE_READ: from the chip, to the controller
+ * @NAND_PAGE_WRITE: from the controller, to the chip
+ */
+enum nand_page_io_req_type {
+	NAND_PAGE_READ = 0,
+	NAND_PAGE_WRITE,
+};
+
 /**
  * struct nand_page_io_req - NAND I/O request object
+ * @type: the type of page I/O: read or write
  * @pos: the position this I/O request is targeting
  * @dataoffs: the offset within the page
  * @datalen: number of data bytes to read from/write to this page
@@ -99,6 +110,7 @@ struct nand_pos {
  * specific commands/operations.
  */
 struct nand_page_io_req {
+	enum nand_page_io_req_type type;
 	struct nand_pos pos;
 	unsigned int dataoffs;
 	unsigned int datalen;
@@ -638,11 +650,13 @@ static inline void nanddev_pos_next_page(struct nand_device *nand,
  * layer.
  */
 static inline void nanddev_io_iter_init(struct nand_device *nand,
+					enum nand_page_io_req_type reqtype,
 					loff_t offs, struct mtd_oob_ops *req,
 					struct nand_io_iter *iter)
 {
 	struct mtd_info *mtd = nanddev_to_mtd(nand);
 
+	iter->req.type = reqtype;
 	iter->req.mode = req->mode;
 	iter->req.dataoffs = nanddev_offs_to_pos(nand, offs, &iter->req.pos);
 	iter->req.ooboffs = req->ooboffs;
@@ -712,8 +726,8 @@ static inline bool nanddev_io_iter_end(struct nand_device *nand,
  *
  * Should be used for iterate over pages that are contained in an MTD request.
  */
-#define nanddev_io_for_each_page(nand, start, req, iter)		\
-	for (nanddev_io_iter_init(nand, start, req, iter);		\
+#define nanddev_io_for_each_page(nand, type, start, req, iter)		\
+	for (nanddev_io_iter_init(nand, type, start, req, iter);	\
 	     !nanddev_io_iter_end(nand, iter);				\
 	     nanddev_io_iter_next_page(nand, iter))