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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 12/15] mtd: spi-nor: core: perform a Soft Reset on shutdown
Date: Fri, 2 Oct 2020 01:50:42 +0530
Message-ID: <20201001202045.21499-13-p.yadav@ti.com> (raw)
In-Reply-To: <20201001202045.21499-1-p.yadav@ti.com>

Perform a Soft Reset on shutdown on flashes that support it so that the
flash can be reset to its initial state and any configurations made by
spi-nor (given that they're only done in volatile registers) will be
reset. This will hand back the flash in pristine state for any further
operations on it.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
---
 drivers/mtd/spi-nor/core.c  | 45 +++++++++++++++++++++++++++++++++++++
 include/linux/mtd/spi-nor.h |  2 ++
 2 files changed, 47 insertions(+)

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index cf6ada7c8a7b..feb4310ff6dc 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -40,6 +40,9 @@
 
 #define SPI_NOR_MAX_ADDR_WIDTH	4
 
+#define SPI_NOR_SRST_SLEEP_MIN 200
+#define SPI_NOR_SRST_SLEEP_MAX 400
+
 /**
  * spi_nor_get_cmd_ext() - Get the command opcode extension based on the
  *			   extension type.
@@ -3175,6 +3178,45 @@ static int spi_nor_init(struct spi_nor *nor)
 	return 0;
 }
 
+static void spi_nor_soft_reset(struct spi_nor *nor)
+{
+	struct spi_mem_op op;
+	int ret;
+
+	op = (struct spi_mem_op)SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_SRSTEN, 0),
+			SPI_MEM_OP_NO_DUMMY,
+			SPI_MEM_OP_NO_ADDR,
+			SPI_MEM_OP_NO_DATA);
+
+	spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
+
+	ret = spi_mem_exec_op(nor->spimem, &op);
+	if (ret) {
+		dev_warn(nor->dev, "Software reset failed: %d\n", ret);
+		return;
+	}
+
+	op = (struct spi_mem_op)SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_SRST, 0),
+			SPI_MEM_OP_NO_DUMMY,
+			SPI_MEM_OP_NO_ADDR,
+			SPI_MEM_OP_NO_DATA);
+
+	spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
+
+	ret = spi_mem_exec_op(nor->spimem, &op);
+	if (ret) {
+		dev_warn(nor->dev, "Software reset failed: %d\n", ret);
+		return;
+	}
+
+	/*
+	 * Software Reset is not instant, and the delay varies from flash to
+	 * flash. Looking at a few flashes, most range somewhere below 100
+	 * microseconds. So, sleep for a range of 200-400 us.
+	 */
+	usleep_range(SPI_NOR_SRST_SLEEP_MIN, SPI_NOR_SRST_SLEEP_MAX);
+}
+
 /* mtd resume handler */
 static void spi_nor_resume(struct mtd_info *mtd)
 {
@@ -3194,6 +3236,9 @@ void spi_nor_restore(struct spi_nor *nor)
 	if (nor->addr_width == 4 && !(nor->flags & SNOR_F_4B_OPCODES) &&
 	    nor->flags & SNOR_F_BROKEN_RESET)
 		nor->params->set_4byte_addr_mode(nor, false);
+
+	if (nor->flags & SNOR_F_SOFT_RESET)
+		spi_nor_soft_reset(nor);
 }
 EXPORT_SYMBOL_GPL(spi_nor_restore);
 
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index cd549042c53d..299685d15dc2 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -51,6 +51,8 @@
 #define SPINOR_OP_CLFSR		0x50	/* Clear flag status register */
 #define SPINOR_OP_RDEAR		0xc8	/* Read Extended Address Register */
 #define SPINOR_OP_WREAR		0xc5	/* Write Extended Address Register */
+#define SPINOR_OP_SRSTEN	0x66	/* Software Reset Enable */
+#define SPINOR_OP_SRST		0x99	/* Software Reset */
 
 /* 4-byte address opcodes - used on Spansion and some Macronix flashes. */
 #define SPINOR_OP_READ_4B	0x13	/* Read data bytes (low frequency) */
-- 
2.28.0


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  parent reply index

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 ` [PATCH v15 07/15] mtd: spi-nor: core: do 2 byte reads for SR and FSR in DTR mode Pratyush Yadav
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 ` Pratyush Yadav [this message]
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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