[PATCH v6 05/14] mtd: spi-nor-core: Add non-uniform erase for Spansion/Cypress

[tkuw584924 at gmail.com]

From: Takahiro Kuwano <Takahiro.Kuwano at infineon.com>

Some of Spansion/Cypress chips have overlaid 4KB sectors at top and/or
bottom, depending on the device configuration, while U-Boot supports
uniform sector layout only.

The spansion_erase_non_uniform()  erases overlaid 4KB sectors,
non-overlaid portion of normal sector, and remaining normal sectors, by
selecting correct erase command and size based on the address to erase
and size of overlaid portion in parameters. Since different Spansion
flashes can use different opcode for erasing the 4K sectors, the opcode
must be passed in as a parameter based on the flash being used.

Signed-off-by: Takahiro Kuwano <Takahiro.Kuwano at infineon.com>
Signed-off-by: Pratyush Yadav <p.yadav at ti.com>
[p.yadav at ti.com: Refactor the function to be compatible with nor->erase,
make 4K opcode customizable, call spi_nor_setup_op() before executing
the op.]
[Takahiro.Kuwano at infineon.com: Remove spi_nor_setup_op() and initialize
op.cmd.buswidth and op.addr.buswidth by 1]
---

Once Pratyush's patch [0] is accepted, I will rebase this series.

[0] https://patchwork.ozlabs.org/project/uboot/patch/20210401193133.18129-27-p.yadav@ti.com/

 drivers/mtd/spi/spi-nor-core.c | 59 ++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
index 829ad36903..1b84e389ad 100644
--- a/drivers/mtd/spi/spi-nor-core.c
+++ b/drivers/mtd/spi/spi-nor-core.c
@@ -739,6 +739,65 @@ erase_err:
 	return ret;
 }
 
+#ifdef CONFIG_SPI_FLASH_SPANSION
+/**
+ * spansion_erase_non_uniform() - erase non-uniform sectors for Spansion/Cypress
+ *                                chips
+ * @nor:	pointer to a 'struct spi_nor'
+ * @addr:	address of the sector to erase
+ * @opcode_4k:	opcode for 4K sector erase
+ * @ovlsz_top:	size of overlaid portion at the top address
+ * @ovlsz_btm:	size of overlaid portion at the bottom address
+ *
+ * Erase an address range on the nor chip that can contain 4KB sectors overlaid
+ * on top and/or bottom. The appropriate erase opcode and size are chosen by
+ * address to erase and size of overlaid portion.
+ *
+ * Return: number of bytes erased on success, -errno otherwise.
+ */
+static int spansion_erase_non_uniform(struct spi_nor *nor, u32 addr,
+				      u8 opcode_4k, u32 ovlsz_top,
+				      u32 ovlsz_btm)
+{
+	struct spi_mem_op op =
+		SPI_MEM_OP(SPI_MEM_OP_CMD(nor->erase_opcode, 1),
+			   SPI_MEM_OP_ADDR(nor->addr_width, addr, 1),
+			   SPI_MEM_OP_NO_DUMMY,
+			   SPI_MEM_OP_NO_DATA);
+	struct mtd_info *mtd = &nor->mtd;
+	u32 erasesize;
+	int ret;
+
+	/* 4KB sectors */
+	if (op.addr.val < ovlsz_btm ||
+	    op.addr.val >= mtd->size - ovlsz_top) {
+		op.cmd.opcode = opcode_4k;
+		erasesize = SZ_4K;
+
+	/* Non-overlaid portion in the normal sector at the bottom */
+	} else if (op.addr.val == ovlsz_btm) {
+		op.cmd.opcode = nor->erase_opcode;
+		erasesize = mtd->erasesize - ovlsz_btm;
+
+	/* Non-overlaid portion in the normal sector at the top */
+	} else if (op.addr.val == mtd->size - mtd->erasesize) {
+		op.cmd.opcode = nor->erase_opcode;
+		erasesize = mtd->erasesize - ovlsz_top;
+
+	/* Normal sectors */
+	} else {
+		op.cmd.opcode = nor->erase_opcode;
+		erasesize = mtd->erasesize;
+	}
+
+	ret = spi_mem_exec_op(nor->spi, &op);
+	if (ret)
+		return ret;
+
+	return erasesize;
+}
+#endif
+
 #if defined(CONFIG_SPI_FLASH_STMICRO) || defined(CONFIG_SPI_FLASH_SST)
 /* Write status register and ensure bits in mask match written values */
 static int write_sr_and_check(struct spi_nor *nor, u8 status_new, u8 mask)
-- 
2.25.1