[PATCH v8 3/8] mtd: spi-nor: Add parallel and stacked memories support in read_bar and write_bar

[Venkatesh Yadav Abbarapu]

From: Ashok Reddy Soma <ashok.reddy.soma at amd.com>

Add support for parallel memories and stacked memories configuration
in read_bar and write_bar functions.

Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma at amd.com>
Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu at amd.com>
---
 drivers/mtd/spi/spi-nor-core.c | 55 +++++++++++++++++++++++++++++-----
 1 file changed, 47 insertions(+), 8 deletions(-)

diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
index 6d1bd4d54a..6ca43aa6e8 100644
--- a/drivers/mtd/spi/spi-nor-core.c
+++ b/drivers/mtd/spi/spi-nor-core.c
@@ -885,12 +885,32 @@ static int clean_bar(struct spi_nor *nor)
 
 static int write_bar(struct spi_nor *nor, u32 offset)
 {
-	u8 cmd, bank_sel;
+	u8 cmd, bank_sel, upage_curr;
 	int ret;
+	struct mtd_info *mtd = &nor->mtd;
+
+	/* Wait until previous write command is finished */
+	if (spi_nor_wait_till_ready(nor))
+		return 1;
+
+	if (nor->flags & (SNOR_F_HAS_PARALLEL | SNOR_F_HAS_STACKED) &&
+	    mtd->size <= SZ_32M)
+		return 0;
+
+	if (mtd->size <= SZ_16M)
+		return 0;
+
+	offset = offset % (u32)mtd->size;
+	bank_sel = offset >> 24;
 
-	bank_sel = offset / SZ_16M;
-	if (bank_sel == nor->bank_curr)
-		goto bar_end;
+	upage_curr = nor->spi->flags & SPI_XFER_U_PAGE;
+
+	if (!(nor->flags & SNOR_F_HAS_STACKED) && bank_sel == nor->bank_curr)
+		return 0;
+	else if (upage_curr == nor->upage_prev && bank_sel == nor->bank_curr)
+		return 0;
+
+	nor->upage_prev = upage_curr;
 
 	cmd = nor->bank_write_cmd;
 	write_enable(nor);
@@ -900,15 +920,19 @@ static int write_bar(struct spi_nor *nor, u32 offset)
 		return ret;
 	}
 
-bar_end:
 	nor->bank_curr = bank_sel;
-	return nor->bank_curr;
+
+	return write_disable(nor);
 }
 
 static int read_bar(struct spi_nor *nor, const struct flash_info *info)
 {
 	u8 curr_bank = 0;
 	int ret;
+	struct mtd_info *mtd = &nor->mtd;
+
+	if (mtd->size <= SZ_16M)
+		return 0;
 
 	switch (JEDEC_MFR(info)) {
 	case SNOR_MFR_SPANSION:
@@ -920,15 +944,30 @@ static int read_bar(struct spi_nor *nor, const struct flash_info *info)
 		nor->bank_write_cmd = SPINOR_OP_WREAR;
 	}
 
+	if (nor->flags & SNOR_F_HAS_PARALLEL)
+		nor->spi->flags |= SPI_XFER_LOWER;
+
 	ret = nor->read_reg(nor, nor->bank_read_cmd,
-				    &curr_bank, 1);
+			    &curr_bank, 1);
 	if (ret) {
 		debug("SF: fail to read bank addr register\n");
 		return ret;
 	}
 	nor->bank_curr = curr_bank;
 
-	return 0;
+	// Make sure both chips use the same BAR
+	if (nor->flags & SNOR_F_HAS_PARALLEL) {
+		write_enable(nor);
+		ret = nor->write_reg(nor, nor->bank_write_cmd, &curr_bank, 1);
+		if (ret)
+			return ret;
+
+		ret = write_disable(nor);
+		if (ret)
+			return ret;
+	}
+
+	return ret;
 }
 #endif
 
-- 
2.25.1