linux-kernel - [PATCH 7/7] mtd: spi-nor: Rework the disabling of write protection at init

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Message-ID: <20190731090315.26798-8-tudor.ambarus@microchip.com>
Date:   Wed, 31 Jul 2019 09:03:39 +0000
From:   <Tudor.Ambarus@...rochip.com>
To:     <boris.brezillon@...labora.com>, <marek.vasut@...il.com>,
        <vigneshr@...com>
CC:     <dwmw2@...radead.org>, <computersforpeace@...il.com>,
        <miquel.raynal@...tlin.com>, <richard@....at>,
        <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <Tudor.Ambarus@...rochip.com>
Subject: [PATCH 7/7] mtd: spi-nor: Rework the disabling of write protection at
 init

From: Tudor Ambarus <tudor.ambarus@...rochip.com>

Rename clear_sr_bp()/disable_write_protection() to better indicate
what the function does.

Get rid of MFR handling and implement specific manufacturer
default_init() fixup hooks.

Signed-off-by: Tudor Ambarus <tudor.ambarus@...rochip.com>
---
 drivers/mtd/spi-nor/spi-nor.c | 64 +++++++++++++++++++++++++++++--------------
 include/linux/mtd/spi-nor.h   |  6 ++--
 2 files changed, 46 insertions(+), 24 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 95ca5dd96403..9b9f9b530207 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -4282,6 +4282,16 @@ static int spi_nor_parse_sfdp(struct spi_nor *nor,
 	return err;
 }
 
+static void atmel_set_default_init(struct spi_nor *nor)
+{
+	nor->disable_write_protection = spi_nor_clear_sr_bp;
+}
+
+static void intel_set_default_init(struct spi_nor *nor)
+{
+	nor->disable_write_protection = spi_nor_clear_sr_bp;
+}
+
 static void macronix_set_default_init(struct spi_nor *nor)
 {
 	nor->quad_enable = macronix_quad_enable;
@@ -4303,6 +4313,14 @@ static void spi_nor_mfr_init_params(struct spi_nor *nor,
 				    struct spi_nor_flash_parameter *params)
 {
 	switch (JEDEC_MFR(nor->info)) {
+	case SNOR_MFR_ATMEL:
+		atmel_set_default_init(nor);
+		break;
+
+	case SNOR_MFR_INTEL:
+		intel_set_default_init(nor);
+		break;
+
 	case SNOR_MFR_MACRONIX:
 		macronix_set_default_init(nor);
 		break;
@@ -4649,6 +4667,23 @@ static int spi_nor_setup(struct spi_nor *nor,
 	return err;
 }
 
+static int spi_nor_disable_write_protection(struct spi_nor *nor)
+{
+	if (!nor->disable_write_protection)
+		return 0;
+
+	/*
+	 * In case of the legacy quad enable requirements are set, if the
+	 * configuration register Quad Enable bit is one, only the the
+	 * Write Status (01h) command with two data bytes may be used to clear
+	 * the block protection bits.
+	 */
+	if (nor->quad_enable == spansion_quad_enable)
+		nor->disable_write_protection = spi_nor_spansion_clear_sr_bp;
+
+	return nor->disable_write_protection(nor);
+}
+
 static int spi_nor_quad_enable(struct spi_nor *nor)
 {
 	if (!nor->quad_enable)
@@ -4665,16 +4700,11 @@ static int spi_nor_init(struct spi_nor *nor)
 {
 	int err;
 
-	if (nor->clear_sr_bp) {
-		if (nor->quad_enable == spansion_quad_enable)
-			nor->clear_sr_bp = spi_nor_spansion_clear_sr_bp;
-
-		err = nor->clear_sr_bp(nor);
-		if (err) {
-			dev_err(nor->dev,
-				"fail to clear block protection bits\n");
-			return err;
-		}
+	err = spi_nor_disable_write_protection(nor);
+	if (err) {
+		dev_err(nor->dev,
+			"fail to unlock the flash at init (err = %d)\n", err);
+		return err;
 	}
 
 	err = spi_nor_quad_enable(nor);
@@ -4797,23 +4827,15 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
 	if (info->flags & SPI_S3AN)
 		nor->flags |=  SNOR_F_READY_XSR_RDY;
 
-	/*
-	 * Atmel, SST, Intel/Numonyx, and others serial NOR tend to power up
-	 * with the software protection bits set.
-	 */
-	if (JEDEC_MFR(nor->info) == SNOR_MFR_ATMEL ||
-	    JEDEC_MFR(nor->info) == SNOR_MFR_INTEL ||
-	    JEDEC_MFR(nor->info) == SNOR_MFR_SST ||
-	    nor->info->flags & SPI_NOR_HAS_LOCK)
-		nor->clear_sr_bp = spi_nor_clear_sr_bp;
-
 	/* Kept only for backward compatibility purpose. */
 	nor->quad_enable = spansion_quad_enable;
 	nor->set_4byte = spansion_set_4byte;
 
 	/* Default locking operations. */
-	if (info->flags & SPI_NOR_HAS_LOCK)
+	if (info->flags & SPI_NOR_HAS_LOCK) {
 		nor->locking_ops = &stm_locking_ops;
+		nor->disable_write_protection = spi_nor_clear_sr_bp;
+	}
 
 	/* Init flash parameters based on flash_info struct and SFDP */
 	spi_nor_init_params(nor, &params);
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index bd68ec5a10e7..185ca11bfb63 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -380,8 +380,8 @@ struct flash_info;
  * @quad_enable:	[FLASH-SPECIFIC] enables SPI NOR quad mode
  * @set_4byte:		[FLASH-SPECIFIC] puts the SPI NOR in 4 byte addressing
  *                      mode
- * @clear_sr_bp:	[FLASH-SPECIFIC] clears the Block Protection Bits from
- *			the SPI NOR Status Register.
+ * @disable_write_protection: [FLASH-SPECIFIC] disable write protection during
+ *                            power-up
  *			completely locked
  * @priv:		the private data
  */
@@ -423,7 +423,7 @@ struct spi_nor {
 	int (*flash_is_locked)(struct spi_nor *nor, loff_t ofs, uint64_t len);
 	int (*quad_enable)(struct spi_nor *nor);
 	int (*set_4byte)(struct spi_nor *nor, bool enable);
-	int (*clear_sr_bp)(struct spi_nor *nor);
+	int (*disable_write_protection)(struct spi_nor *nor);
 
 	const struct spi_nor_locking_ops *locking_ops;
 
-- 
2.9.5