mtd: spi-nor: add Kconfig option to disable 4K sectors (57cf26c1) · Commits · 戴 / test

Current situation with 4K sectors is quite messy. First of all, some MTD "users" don't work with such small size. An example may be UBIFS which requires 15 KiB erase blocks as a minimum. In theory spi-nor should provide multiple erase regions and MTD "users" should use the one they need. Unforunately that is not implemented. In the result our flashes database in spi-nor is hackish. For some flashes we pretend they don't support 4K sectors just because some distribution uses UBIFS on it. This ofc leads to conflicts, like Samsung using w25q128 with 4K sectors vs. OpenWrt requiring it to pretend it's 64 KiB blocks only. My idea (plan?) for fixing this situation: 1) Use real hw info (this requires a way for disabling 4K for now) 2) Provide detailed info about erase regions 3) Make UBIFS work with devices that support 4K sectors Signed-off-by:

Rafał Miłecki <zajec5@gmail.com> Signed-off-by:

Brian Norris <computersforpeace@gmail.com>

drivers/mtd/spi-nor/Kconfig

+14 −0

Original line number	Diff line number	Diff line
		@@ -7,6 +7,20 @@ menuconfig MTD_SPI_NOR

		if MTD_SPI_NOR

		config MTD_SPI_NOR_USE_4K_SECTORS
		bool "Use small 4096 B erase sectors"
		default y
		help
		Many flash memories support erasing small (4096 B) sectors. Depending
		on the usage this feature may provide performance gain in comparison
		to erasing whole blocks (32/64 KiB).
		Changing a small part of the flash's contents is usually faster with
		small sectors. On the other hand erasing should be faster when using
		64 KiB block instead of 16 × 4 KiB sectors.

		Please note that some tools/drivers/filesystems may not work with
		4096 B erase size (e.g. UBIFS requires 15 KiB as a minimum).

		config SPI_FSL_QUADSPI
		tristate "Freescale Quad SPI controller"
		depends on ARCH_MXC

drivers/mtd/spi-nor/spi-nor.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -1013,6 +1013,7 @@ int spi_nor_scan(struct spi_nor nor, const struct spi_device_id id,
		nor->wait_till_ready == spi_nor_wait_till_ready)
		nor->wait_till_ready = spi_nor_wait_till_fsr_ready;

		#ifdef CONFIG_MTD_SPI_NOR_USE_4K_SECTORS
		/* prefer "small sector" erase if possible */
		if (info->flags & SECT_4K) {
		nor->erase_opcode = SPINOR_OP_BE_4K;
		@@ -1020,7 +1021,9 @@ int spi_nor_scan(struct spi_nor nor, const struct spi_device_id id,
		} else if (info->flags & SECT_4K_PMC) {
		nor->erase_opcode = SPINOR_OP_BE_4K_PMC;
		mtd->erasesize = 4096;
		} else {
		} else
		#endif
		{
		nor->erase_opcode = SPINOR_OP_SE;
		mtd->erasesize = info->sector_size;
		}

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