mtd: spi-nor: Use spi-mem dirmap API

This adds support for the dirmap API to the spi-nor subsystem, as
introduced in Linux commit df5c21002cf4  ("mtd: spi-nor: use
spi-mem dirmap API").

This patch is synchronize from the following patch
https://patchwork.ozlabs.org/project/uboot/patch/20210205043924.149504-4-seanga2@gmail.com/
The corresponding Linux kernel SHA1 is df5c21002cf4.

Signed-off-by: Chin-Ting Kuo <chin-ting_kuo@aspeedtech.com>
Signed-off-by: Sean Anderson <seanga2@gmail.com>
Acked-by: Pratyush Yadav <p.yadav@ti.com>
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 2595bad..638d807 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -11,6 +11,7 @@
 #include <linux/bitops.h>
 #include <linux/mtd/cfi.h>
 #include <linux/mtd/mtd.h>
+#include <spi-mem.h>
 
 /*
  * Manufacturer IDs
@@ -522,6 +523,7 @@
  * @quad_enable:	[FLASH-SPECIFIC] enables SPI NOR quad mode
  * @octal_dtr_enable:	[FLASH-SPECIFIC] enables SPI NOR octal DTR mode.
  * @ready:		[FLASH-SPECIFIC] check if the flash is ready
+ * @dirmap:		pointers to struct spi_mem_dirmap_desc for reads/writes.
  * @priv:		the private data
  */
 struct spi_nor {
@@ -572,6 +574,11 @@
 	int (*octal_dtr_enable)(struct spi_nor *nor);
 	int (*ready)(struct spi_nor *nor);
 
+	struct {
+		struct spi_mem_dirmap_desc *rdesc;
+		struct spi_mem_dirmap_desc *wdesc;
+	} dirmap;
+
 	void *priv;
 	char mtd_name[MTD_NAME_SIZE(MTD_DEV_TYPE_NOR)];
 /* Compatibility for spi_flash, remove once sf layer is merged with mtd */
@@ -596,6 +603,17 @@
 #endif /* __UBOOT__ */
 
 /**
+ * spi_nor_setup_op() - Set up common properties of a spi-mem op.
+ * @nor:		pointer to a 'struct spi_nor'
+ * @op:			pointer to the 'struct spi_mem_op' whose properties
+ *			need to be initialized.
+ * @proto:		the protocol from which the properties need to be set.
+ */
+void spi_nor_setup_op(const struct spi_nor *nor,
+		      struct spi_mem_op *op,
+		      const enum spi_nor_protocol proto);
+
+/**
  * spi_nor_scan() - scan the SPI NOR
  * @nor:	the spi_nor structure
  *