linux-kernel - [PATCH 4/5] mtd: spi-nor: Move clear_sr_bp() to 'struct spi_nor_flash

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Date:   Fri, 23 Aug 2019 15:53:41 +0000
From:   <Tudor.Ambarus@...rochip.com>
To:     <marek.vasut@...il.com>, <vigneshr@...com>,
        <boris.brezillon@...labora.com>, <miquel.raynal@...tlin.com>,
        <richard@....at>, <linux-mtd@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
CC:     <Tudor.Ambarus@...rochip.com>
Subject: [PATCH 4/5] mtd: spi-nor: Move clear_sr_bp() to 'struct
 spi_nor_flash_parameter'

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

All flash parameters and settings should reside inside
'struct spi_nor_flash_parameter'. Move clear_sr_bp() from
'struct spi_nor' to 'struct spi_nor_flash_parameter'.

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

Signed-off-by: Tudor Ambarus <tudor.ambarus@...rochip.com>
---
 drivers/mtd/spi-nor/spi-nor.c | 47 +++++++++++++++++++++++++++++++++----------
 include/linux/mtd/spi-nor.h   |  5 ++---
 2 files changed, 38 insertions(+), 14 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 6bd104c29cd9..15b0b1148bf3 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -4477,20 +4477,45 @@ static int spi_nor_quad_enable(struct spi_nor *nor)
 	return nor->params.quad_enable(nor);
 }
 
+/**
+ * spi_nor_disable_block_protection() - Disable the write block protection
+ * during power-up.
+ * @nor:                pointer to a 'struct spi_nor'
+ *
+ * Some spi-nor flashes are write protected by default after a power-on reset
+ * cycle, in order to avoid inadvertend writes during power-up. Backward
+ * compatibility imposes to disable the write block protection at power-up
+ * by default.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+static int spi_nor_disable_block_protection(struct spi_nor *nor)
+{
+	if (!nor->params.disable_block_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->params.quad_enable == spansion_quad_enable)
+		nor->params.disable_block_protection =
+			spi_nor_spansion_clear_sr_bp;
+
+	return nor->params.disable_block_protection(nor);
+}
+
 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_block_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);
@@ -4635,7 +4660,7 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
 	    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;
+		nor->params.disable_block_protection = spi_nor_clear_sr_bp;
 
 	/* Parse the Serial Flash Discoverable Parameters table. */
 	ret = spi_nor_init_params(nor);
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 17787238f0e9..399ac34a529d 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -480,6 +480,7 @@ struct spi_nor;
  * @page_programs:	page program capabilities ordered by priority: the
  *                      higher index in the array, the higher priority.
  * @quad_enable:	enables SPI NOR quad mode.
+ * @disable_block_protection: disables block protection during power-up.
  */
 struct spi_nor_flash_parameter {
 	u64				size;
@@ -490,6 +491,7 @@ struct spi_nor_flash_parameter {
 	struct spi_nor_pp_command	page_programs[SNOR_CMD_PP_MAX];
 
 	int (*quad_enable)(struct spi_nor *nor);
+	int (*disable_block_protection)(struct spi_nor *nor);
 };
 
 /**
@@ -535,8 +537,6 @@ struct flash_info;
  * @flash_unlock:	[FLASH-SPECIFIC] unlock a region of the SPI NOR
  * @flash_is_locked:	[FLASH-SPECIFIC] check if a region of the SPI NOR is
  *			completely locked
- * @clear_sr_bp:	[FLASH-SPECIFIC] clears the Block Protection Bits from
- *			the SPI NOR Status Register.
  * @params:		[FLASH-SPECIFIC] SPI-NOR flash parameters and settings.
  *                      The structure includes legacy flash parameters and
  *                      settings that can be overwritten by the spi_nor_fixups
@@ -578,7 +578,6 @@ struct spi_nor {
 	int (*flash_lock)(struct spi_nor *nor, loff_t ofs, uint64_t len);
 	int (*flash_unlock)(struct spi_nor *nor, loff_t ofs, uint64_t len);
 	int (*flash_is_locked)(struct spi_nor *nor, loff_t ofs, uint64_t len);
-	int (*clear_sr_bp)(struct spi_nor *nor);
 	struct spi_nor_flash_parameter params;
 
 	void *priv;
-- 
2.9.5