Add 'size' data variable in spi_device struct.
This is to save the size of the connected slave device.

After slave device scan, spi_nor_scan, size being assigned to this
from MTD layer.

SFDP read is being requested before completion of spi_nor_scan()
routine, thus populate device size before making read request
to the SPI controller.

Signed-off-by: Yogesh Gaur <redacted>
---
 drivers/mtd/devices/m25p80.c  | 6 ++++++
 drivers/mtd/spi-nor/spi-nor.c | 2 ++
 include/linux/spi/spi.h       | 2 ++
 3 files changed, 10 insertions(+)

diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index fe260cc..6c7ad86 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c

@@ -124,6 +124,10 @@ static ssize_t m25p80_read(struct spi_nor *nor, loff_t from, size_t len,
 	/* convert the dummy cycles to the number of bytes */
 	op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
 
+	/* for case of SFDP header read commands, populate spi device size */
+	if (flash->spimem->spi->size == 0)
+		flash->spimem->spi->size = nor->mtd.size;
+