kernel/linux.git/drivers/mtd/Kconfig, branch v6.12.80

mtdblock: Add comment about UBI block devices

2021-08-06T20:05:13+00:00

There is a surprisingly large number of tutorials that suggest using mtdblock to mount SquashFS filesystems on flash devices, including NAND devices. Given this approach is suboptimal than using UBI, and given the UBI block device layer was introduced many years ago specifically with this use case in mind, add a small comment inviting users and developers to consider UBI block. Signed-off-by: Ezequiel Garcia Signed-off-by: Miquel Raynal Link: https://lore.kernel.org/linux-mtd/20210801234509.18774-7-ezequiel@collabora.com

mtdblock: Update old JFFS2 mention in Kconfig

2021-08-06T20:05:10+00:00

JFFS2 can be mounted without 'mtdblock' since a really, really long time. Some git-log archaeology shows that in 2006 it was possible to use 'root=' to mount a JFFS2 rootfs: commit e9482b4374e2596e6f3f1ab30c4ea469f4ac6311 Author: Joern Engel Date: Tue May 30 14:25:46 2006 +0200 [MTD] Allow alternate JFFS2 mount variant for root filesystem. With this patch, "root=mtd3" and "root=mtd:foo" work for a JFFS2 rootfs. However, there are still plenty of tutorials that mention mtdblock, so users are still taking this route. Update the Kconfig to reflect this is no longer needed. Signed-off-by: Ezequiel Garcia Signed-off-by: Miquel Raynal Link: https://lore.kernel.org/linux-mtd/20210801234509.18774-6-ezequiel@collabora.com

mtd: nand: ecc-hamming: Move Hamming code to the generic NAND layer

2020-12-10T21:37:29+00:00

Hamming ECC code might be later re-used by the SPI NAND layer. Signed-off-by: Miquel Raynal Link: https://lore.kernel.org/linux-mtd/20200929230124.31491-12-miquel.raynal@bootlin.com

mtd: Support kmsg dumper based on pstore/blk

2020-06-01T02:49:01+00:00

This introduces mtdpstore, which is similar to mtdoops but more powerful. It uses pstore/blk, and aims to store panic and oops logs to a flash partition, where pstore can later read back and present as files in the mounted pstore filesystem. To make mtdpstore work, the "blkdev" of pstore/blk should be set as MTD device name or MTD device number. For more details, see Documentation/admin-guide/pstore-blk.rst This solves a number of issues: - Work duplication: both of pstore and mtdoops do the same job storing panic/oops log. They have very similar logic, registering to kmsg dumper and storing logs to several chunks one by one. - Layer violations: drivers should provides methods instead of polices. MTD should provide read/write/erase operations, and allow a higher level drivers to provide the chunk management, kmsg dump configuration, etc. - Missing features: pstore provides many additional features, including presenting the logs as files, logging dump time and count, and supporting other frontends like pmsg, console, etc. Signed-off-by: WeiXiong Liao Link: https://lore.kernel.org/lkml/20200511233229.27745-11-keescook@chromium.org/ Link: https://lore.kernel.org/r/1589266715-4168-1-git-send-email-liaoweixiong@allwinnertech.com Signed-off-by: Kees Cook

mtd: parsers: Move CMDLINE parser

2019-09-15T21:50:50+00:00

This moves the CMDLINE partition parser down into the parser subdirectory. No functional change. Signed-off-by: Linus Walleij Signed-off-by: Richard Weinberger

mtd: parsers: Move OF parser

2019-09-15T21:50:49+00:00

This moves the OF/device tree partition parser down into the parser subdirectory. No functional change. Signed-off-by: Linus Walleij Signed-off-by: Richard Weinberger

mtd: parsers: Move BCM63xx parser

2019-09-15T21:50:49+00:00

This moves the BCM63xx partition parser down into the parser subdirectory. No functional change. Signed-off-by: Linus Walleij Signed-off-by: Richard Weinberger

mtd: parsers: Move BCM47xx parser

2019-09-15T21:50:48+00:00

This moves the BCM47xx partition parser down into the parser subdirectory. No functional change. Signed-off-by: Linus Walleij Signed-off-by: Richard Weinberger

mtd: parsers: Move TI AR7 parser

2019-09-15T21:50:48+00:00

This moves the TI AR7 partition parser down into the parser subdirectory. No functional change. Signed-off-by: Linus Walleij Signed-off-by: Richard Weinberger

mtd: Add support for HyperBus memory devices

2019-06-27T17:47:58+00:00

Cypress' HyperBus is Low Signal Count, High Performance Double Data Rate Bus interface between a host system master and one or more slave interfaces. HyperBus is used to connect microprocessor, microcontroller, or ASIC devices with random access NOR flash memory (called HyperFlash) or self refresh DRAM (called HyperRAM). Its a 8-bit data bus (DQ[7:0]) with Read-Write Data Strobe (RWDS) signal and either Single-ended clock(3.0V parts) or Differential clock (1.8V parts). It uses ChipSelect lines to select b/w multiple slaves. At bus level, it follows a separate protocol described in HyperBus specification[1]. HyperFlash follows CFI AMD/Fujitsu Extended Command Set (0x0002) similar to that of existing parallel NORs. Since HyperBus is x8 DDR bus, its equivalent to x16 parallel NOR flash with respect to bits per clock cycle. But HyperBus operates at >166MHz frequencies. HyperRAM provides direct random read/write access to flash memory array. But, HyperBus memory controllers seem to abstract implementation details and expose a simple MMIO interface to access connected flash. Add support for registering HyperFlash devices with MTD framework. MTD maps framework along with CFI chip support framework are used to support communicating with flash. Framework is modelled along the lines of spi-nor framework. HyperBus memory controller (HBMC) drivers calls hyperbus_register_device() to register a single HyperFlash device. HyperFlash core parses MMIO access information from DT, sets up the map_info struct, probes CFI flash and registers it with MTD framework. Some HBMC masters need calibration/training sequence[3] to be carried out, in order for DLL inside the controller to lock, by reading a known string/pattern. This is done by repeatedly reading CFI Query Identification String. Calibration needs to be done before trying to detect flash as part of CFI flash probe. HyperRAM is not supported at the moment. HyperBus specification can be found at[1] HyperFlash datasheet can be found at[2] [1] https://www.cypress.com/file/213356/download [2] https://www.cypress.com/file/213346/download [3] http://www.ti.com/lit/ug/spruid7b/spruid7b.pdf Table 12-5741. HyperFlash Access Sequence Signed-off-by: Vignesh Raghavendra Signed-off-by: Miquel Raynal