From: Pratyush Yadav <p.yadav@ti.com>
To: Tudor Ambarus <tudor.ambarus@microchip.com>,
Miquel Raynal <miquel.raynal@bootlin.com>,
Richard Weinberger <richard@nod.at>,
Vignesh Raghavendra <vigneshr@ti.com>,
<linux-mtd@lists.infradead.org>, <linux-kernel@vger.kernel.org>
Cc: Boris Brezillon <boris.brezillon@collabora.com>,
Sekhar Nori <nsekhar@ti.com>, Pratyush Yadav <p.yadav@ti.com>
Subject: [PATCH v15 07/15] mtd: spi-nor: core: do 2 byte reads for SR and FSR in DTR mode
Date: Fri, 2 Oct 2020 01:50:37 +0530 [thread overview]
Message-ID: <20201001202045.21499-8-p.yadav@ti.com> (raw)
In-Reply-To: <20201001202045.21499-1-p.yadav@ti.com>
Some controllers, like the cadence qspi controller, have trouble reading
only 1 byte in DTR mode. So, do 2 byte reads for SR and FSR commands in
DTR mode, and then discard the second byte.
Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
---
drivers/mtd/spi-nor/core.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index b5bb4d6cffc1..b83bf5ed2b2d 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -370,7 +370,7 @@ int spi_nor_write_disable(struct spi_nor *nor)
* spi_nor_read_sr() - Read the Status Register.
* @nor: pointer to 'struct spi_nor'.
* @sr: pointer to a DMA-able buffer where the value of the
- * Status Register will be written.
+ * Status Register will be written. Should be at least 2 bytes.
*
* Return: 0 on success, -errno otherwise.
*/
@@ -388,6 +388,11 @@ static int spi_nor_read_sr(struct spi_nor *nor, u8 *sr)
if (nor->reg_proto == SNOR_PROTO_8_8_8_DTR) {
op.addr.nbytes = nor->params->rdsr_addr_nbytes;
op.dummy.nbytes = nor->params->rdsr_dummy;
+ /*
+ * We don't want to read only one byte in DTR mode. So,
+ * read 2 and then discard the second byte.
+ */
+ op.data.nbytes = 2;
}
spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
@@ -408,7 +413,8 @@ static int spi_nor_read_sr(struct spi_nor *nor, u8 *sr)
* spi_nor_read_fsr() - Read the Flag Status Register.
* @nor: pointer to 'struct spi_nor'
* @fsr: pointer to a DMA-able buffer where the value of the
- * Flag Status Register will be written.
+ * Flag Status Register will be written. Should be at least 2
+ * bytes.
*
* Return: 0 on success, -errno otherwise.
*/
@@ -426,6 +432,11 @@ static int spi_nor_read_fsr(struct spi_nor *nor, u8 *fsr)
if (nor->reg_proto == SNOR_PROTO_8_8_8_DTR) {
op.addr.nbytes = nor->params->rdsr_addr_nbytes;
op.dummy.nbytes = nor->params->rdsr_dummy;
+ /*
+ * We don't want to read only one byte in DTR mode. So,
+ * read 2 and then discard the second byte.
+ */
+ op.data.nbytes = 2;
}
spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
--
2.28.0
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next prev parent reply other threads:[~2020-10-01 20:22 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-01 20:20 [PATCH v15 00/15] mtd: spi-nor: add xSPI Octal DTR support Pratyush Yadav
2020-10-01 20:20 ` [PATCH v15 01/15] mtd: spi-nor: core: use EOPNOTSUPP instead of ENOTSUPP Pratyush Yadav
2020-10-01 20:20 ` [PATCH v15 02/15] mtd: spi-nor: add spi_nor_controller_ops_{read_reg, write_reg, erase}() Pratyush Yadav
2020-10-01 20:20 ` [PATCH v15 03/15] mtd: spi-nor: add support for DTR protocol Pratyush Yadav
2020-10-01 20:20 ` [PATCH v15 04/15] mtd: spi-nor: sfdp: get command opcode extension type from BFPT Pratyush Yadav
2020-10-01 20:20 ` [PATCH v15 05/15] mtd: spi-nor: sfdp: parse xSPI Profile 1.0 table Pratyush Yadav
2020-10-01 20:20 ` [PATCH v15 06/15] mtd: spi-nor: core: use dummy cycle and address width info from SFDP Pratyush Yadav
2020-10-01 20:20 ` Pratyush Yadav [this message]
2020-10-01 20:20 ` [PATCH v15 08/15] mtd: spi-nor: Introduce SNOR_F_IO_MODE_EN_VOLATILE Pratyush Yadav
2020-10-01 20:20 ` [PATCH v15 09/15] mtd: spi-nor: Parse SFDP SCCR Map Pratyush Yadav
2020-10-01 20:20 ` [PATCH v15 10/15] mtd: spi-nor: core: enable octal DTR mode when possible Pratyush Yadav
2020-10-02 9:47 ` Tudor.Ambarus
2020-10-01 20:20 ` [PATCH v15 11/15] mtd: spi-nor: sfdp: detect Soft Reset sequence support from BFPT Pratyush Yadav
2020-10-01 20:20 ` [PATCH v15 12/15] mtd: spi-nor: core: perform a Soft Reset on shutdown Pratyush Yadav
2020-10-01 20:20 ` [PATCH v15 13/15] mtd: spi-nor: core: disable Octal DTR mode on suspend Pratyush Yadav
2020-10-01 20:20 ` [PATCH v15 14/15] mtd: spi-nor: spansion: add support for Cypress Semper flash Pratyush Yadav
2020-10-03 11:40 ` Vignesh Raghavendra
2020-10-01 20:20 ` [PATCH v15 15/15] mtd: spi-nor: micron-st: allow using MT35XU512ABA in Octal DTR mode Pratyush Yadav
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