[SRU][Artful][PATCH 2/2] spi-nor: intel-spi: Fix broken software sequencing codes

[Joseph Salisbury]

From: Bin Meng <bmeng.cn at gmail.com>

BugLink: http://bugs.launchpad.net/bugs/1742696

There are two bugs in current intel_spi_sw_cycle():

- The 'data byte count' field should be the number of bytes
  transferred minus 1
- SSFSTS_CTL is the offset from ispi->sregs, not ispi->base

Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
Cc: <stable at vger.kernel.org> # v4.11+
Acked-by: Mika Westerberg <mika.westerberg at linux.intel.com>
Signed-off-by: Cyrille Pitchen <cyrille.pitchen at wedev4u.fr>
(cherry picked from commit 9d63f17661e25fd28714dac94bdebc4ff5b75f09)
Signed-off-by: Joseph Salisbury <joseph.salisbury at canonical.com>
---
 drivers/mtd/spi-nor/intel-spi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/spi-nor/intel-spi.c b/drivers/mtd/spi-nor/intel-spi.c
index 8a596bf..7802ac3 100644
--- a/drivers/mtd/spi-nor/intel-spi.c
+++ b/drivers/mtd/spi-nor/intel-spi.c
@@ -422,7 +422,7 @@ static int intel_spi_sw_cycle(struct intel_spi *ispi, u8 opcode, u8 *buf,
 	if (ret < 0)
 		return ret;
 
-	val = (len << SSFSTS_CTL_DBC_SHIFT) | SSFSTS_CTL_DS;
+	val = ((len - 1) << SSFSTS_CTL_DBC_SHIFT) | SSFSTS_CTL_DS;
 	val |= ret << SSFSTS_CTL_COP_SHIFT;
 	val |= SSFSTS_CTL_FCERR | SSFSTS_CTL_FDONE;
 	val |= SSFSTS_CTL_SCGO;
@@ -432,7 +432,7 @@ static int intel_spi_sw_cycle(struct intel_spi *ispi, u8 opcode, u8 *buf,
 	if (ret)
 		return ret;
 
-	status = readl(ispi->base + SSFSTS_CTL);
+	status = readl(ispi->sregs + SSFSTS_CTL);
 	if (status & SSFSTS_CTL_FCERR)
 		return -EIO;
 	else if (status & SSFSTS_CTL_AEL)
-- 
2.7.4