[PATCH 3/4] mtd: spinand: Enabled support to detect parameter page

[Shivamurthy Shastri (sshivamurthy)]

Some of the SPI NAND devices has parameter page which is similar to ONFI
table.

But, it may not be self sufficient to propagate all the required
parameters. Fixup function has been added in struct manufacturer to
accommodate this.

Signed-off-by: Shivamurthy Shastri <sshivamurthy@xxxxxxxxxx>
---
 drivers/mtd/nand/spi/core.c | 113 +++++++++++++++++++++++++++++++++++-
 include/linux/mtd/spinand.h |   5 ++
 2 files changed, 117 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
index 985ad52cdaa7..40882a1d2bc1 100644
--- a/drivers/mtd/nand/spi/core.c
+++ b/drivers/mtd/nand/spi/core.c
@@ -574,6 +574,108 @@ static int spinand_lock_block(struct spinand_device *spinand, u8 lock)
 	return spinand_write_reg_op(spinand, REG_BLOCK_LOCK, lock);
 }
 
+/**
+ * spinand_read_param_page_op - Read parameter page operation
+ * @spinand: the spinand device
+ * @page: page number where parameter page tables can be found
+ * @parameters: buffer used to store the parameter page
+ * @len: length of the buffer
+ *
+ * Read parameter page
+ *
+ * Returns 0 on success, a negative error code otherwise.
+ */
+static int spinand_parameter_page_read(struct nand_device *base,
+				       u8 page, void *buf, unsigned int len)
+{
+	struct spinand_device *spinand = nand_to_spinand(base);
+	struct spi_mem_op pread_op = SPINAND_PAGE_READ_OP(page);
+	struct spi_mem_op pread_cache_op =
+				SPINAND_PAGE_READ_FROM_CACHE_OP(false,
+								0,
+								1,
+								buf,
+								len);
+	u8 feature;
+	u8 status;
+	int ret;
+
+	if (len && !buf)
+		return -EINVAL;
+
+	ret = spinand_read_reg_op(spinand, REG_CFG,
+				  &feature);
+	if (ret)
+		return ret;
+
+	/* CFG_OTP_ENABLE is used to enable parameter page access */
+	feature |= CFG_OTP_ENABLE;
+
+	spinand_write_reg_op(spinand, REG_CFG, feature);
+
+	ret = spi_mem_exec_op(spinand->spimem, &pread_op);
+	if (ret)
+		return ret;
+
+	ret = spinand_wait(spinand, &status);
+	if (ret < 0)
+		return ret;
+
+	ret = spi_mem_exec_op(spinand->spimem, &pread_cache_op);
+	if (ret)
+		return ret;
+
+	ret = spinand_read_reg_op(spinand, REG_CFG,
+				  &feature);
+	if (ret)
+		return ret;
+
+	feature &= ~CFG_OTP_ENABLE;
+
+	spinand_write_reg_op(spinand, REG_CFG, feature);
+
+	return 1;
+}
+
+static int check_version(struct nand_device *base,
+			 struct nand_onfi_params *p, int *onfi_version)
+{
+	/**
+	 * SPI NAND do not support ONFI standard
+	 * But, parameter page looks same as ONFI table
+	 */
+	if (!le16_to_cpu(p->revision))
+		*onfi_version = 0;
+
+	return 1;
+}
+
+static int spinand_intf_data(struct nand_device *base,
+			     struct nand_onfi_params *p)
+{
+	struct spinand_device *spinand = nand_to_spinand(base);
+
+	/**
+	 *	Manufacturers may interpret the parameter page differently
+	 */
+	if (spinand->manufacturer->ops->fixup_param_page)
+		spinand->manufacturer->ops->fixup_param_page(spinand, p);
+
+	return 1;
+}
+
+static int spinand_param_page_detect(struct spinand_device *spinand)
+{
+	struct nand_device *base = spinand_to_nand(spinand);
+
+	base->helper.page = 0x01;
+	base->helper.check_revision = check_version;
+	base->helper.parameter_page_read = spinand_parameter_page_read;
+	base->helper.init_intf_data = spinand_intf_data;
+
+	return nand_onfi_detect(base);
+}
+
 static int spinand_read_page(struct spinand_device *spinand,
 			     const struct nand_page_io_req *req)
 {
@@ -896,7 +998,7 @@ static void spinand_manufacturer_cleanup(struct spinand_device *spinand)
 		return spinand->manufacturer->ops->cleanup(spinand);
 }
 
-static const struct spi_mem_op *
+const struct spi_mem_op *
 spinand_select_op_variant(struct spinand_device *spinand,
 			  const struct spinand_op_variants *variants)
 {
@@ -1012,6 +1114,15 @@ static int spinand_detect(struct spinand_device *spinand)
 		return ret;
 	}
 
+	if (!spinand->base.memorg.pagesize) {
+		ret = spinand_param_page_detect(spinand);
+		if (ret < 0) {
+			dev_err(dev, "no parameter page for %*phN\n",
+				SPINAND_MAX_ID_LEN, spinand->id.data);
+			return ret;
+		}
+	}
+
 	if (nand->memorg.ntargets > 1 && !spinand->select_target) {
 		dev_err(dev,
 			"SPI NANDs with more than one die must implement ->select_target()\n");
diff --git a/include/linux/mtd/spinand.h b/include/linux/mtd/spinand.h
index d093d237fba8..57b3b5b075f2 100644
--- a/include/linux/mtd/spinand.h
+++ b/include/linux/mtd/spinand.h
@@ -179,6 +179,8 @@ struct spinand_manufacturer_ops {
 	int (*detect)(struct spinand_device *spinand);
 	int (*init)(struct spinand_device *spinand);
 	void (*cleanup)(struct spinand_device *spinand);
+	void (*fixup_param_page)(struct spinand_device *spinand,
+				 struct nand_onfi_params *p);
 };
 
 /**
@@ -429,4 +431,7 @@ int spinand_match_and_init(struct spinand_device *dev,
 int spinand_upd_cfg(struct spinand_device *spinand, u8 mask, u8 val);
 int spinand_select_target(struct spinand_device *spinand, unsigned int target);
 
+const struct spi_mem_op *spinand_select_op_variant(struct spinand_device *spinand,
+	   const struct spinand_op_variants *variants);
+
 #endif /* __LINUX_MTD_SPINAND_H */
-- 
2.17.1