According to the Denali NAND Flash Memory Controller User's Guide,
this IP has two reset signals.
rst_n: reset most of FFs in the controller core
reg_rst_n: reset all FFs in the register interface, and in the
initialization sequencer
This commit specifies these reset signals.
It is possible to control them separately from the IP point of view
although they might be often tied up together in actual SoC integration.
At least for the upstream platforms, Altera/Intel SOCFPGA and Socionext
UniPhier, the reset controller seems to provide only 1-bit control for
the NAND controller. If it is the case, the resets property should
reference to the same phandles for "nand" and "reg" resets, like this:
resets = <&nand_rst>, <&nand_rst>;
reset-names = "nand", "reg";
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
While my email address has changed for a while, all the schemas I
contributed still have the old one unfortunately. Update it.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: Rob Herring <robh@kernel.org>
Pull Devicetree updates from Rob Herring:
- DT schemas for PWM, syscon, power domains, SRAM, syscon-reboot,
syscon-poweroff, renesas-irqc, simple-pm-bus, renesas-bsc, pwm-rcar,
Renesas tpu, at24 eeprom, rtc-sh, Allwinner PS/2, sharp,ld-d5116z01b
panel, Arm SMMU, max77650, Meson CEC, Amlogic canvas and DWC3 glue,
Allwinner A10 mUSB and CAN, TI Davinci MDIO, QCom QCS404
interconnect, Unisoc/Spreadtrum SoCs and UART
- Convert a bunch of Samsung bindings to DT schema
- Convert a bunch of ST stm32 bindings to DT schema
- Realtek and Exynos additions to Arm Mali bindings
- Fix schema errors in RiscV CPU schema
- Various schema fixes from improved meta-schema checks
- Improve the handling of 'dma-ranges' and in particular fix DMA mask
setup on PCI bridges
- Fix a memory leak in add_changeset_property() and DT unit tests.
- Several documentation improvements for schema validation
- Rework build rules to improve schema validation errors
- Color output for dtx_diff
* tag 'devicetree-for-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (138 commits)
libfdt: define INT32_MAX and UINT32_MAX in libfdt_env.h
dt-bindings: arm: Remove leftover axentia.txt
of: unittest: fix memory leak in attach_node_and_children
of: overlay: add_changeset_property() memory leak
dt-bindings: interrupt-controller: arm,gic-v3: Add missing type to interrupt-partition-* nodes
dt-bindings: firmware: ixp4xx: Drop redundant minItems/maxItems
dt-bindings: power: Rename back power_domain.txt bindings to fix references
dt-bindings: i2c: stm32: Migrate i2c-stm32 documentation to yaml
dt-bindings: mtd: Convert stm32 fmc2-nand bindings to json-schema
dt-bindings: remoteproc: convert stm32-rproc to json-schema
dt-bindings: mailbox: convert stm32-ipcc to json-schema
dt-bindings: mfd: Convert stm32 low power timers bindings to json-schema
dt-bindings: interrupt-controller: Convert stm32-exti to json-schema
dt-bindings: crypto: Convert stm32 HASH bindings to json-schema
dt-bindings: rng: Convert stm32 RNG bindings to json-schema
dt-bindings: pwm: Convert Samsung PWM bindings to json-schema
dt-bindings: pwm: Convert PWM bindings to json-schema
dt-bindings: serial: Add a new compatible string for SC9863A
dt-bindings: serial: Convert sprd-uart to json-schema
dt-bindings: arm: Add bindings for Unisoc SC9863A
...
Raw NAND core
* Useless extra checks dropped.
* Updated the detection of the bad block markers position
Raw NAND controller drivers:
* Cadence : New driver
* Brcmnand: Support for flash-dma v0 + fixes
* Denali : Support for the legacy controller/chip DT representation
dropped
* Superfluous dev_err() calls removed
This adds device tree bindings for the Intel IXP4xx
flash controller, a simple physmap which however need a
specific big-endian or mixed-endian access pattern to the
memory.
Cc: devicetree@vger.kernel.org
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Pull MTD updates from Miquel Raynal:
"This contains the following changes for MTD:
MTD core changes:
- New Hyperbus framework
- New _is_locked (concat) implementation
- Various cleanups
NAND core changes:
- use longest matching pattern in ->exec_op() default parser
- export NAND operation tracer
- add flag to indicate panic_write in MTD
- use kzalloc() instead of kmalloc() and memset()
Raw NAND controller drivers changes:
- brcmnand:
- fix BCH ECC layout for large page NAND parts
- fallback to detected ecc-strength, ecc-step-size
- when oops in progress use pio and interrupt polling
- code refactor code to introduce helper functions
- add support for v7.3 controller
- FSMC:
- use nand_op_trace for operation tracing
- GPMI:
- move all driver code into single file
- various cleanups (including dmaengine changes)
- use runtime PM to manage clocks
- implement exec_op
- MTK:
- correct low level time calculation of r/w cycle
- improve data sampling timing for read cycle
- add validity check for CE# pin setting
- fix wrongly assigned OOB buffer pointer issue
- re-license MTK NAND driver as Dual MIT/GPL
- STM32:
- manage the get_irq error case
- increase DMA completion timeouts
Raw NAND chips drivers changes:
- Macronix: add read-retry support
Onenand driver changes:
- add support for 8Gb datasize chips
- avoid fall-through warnings
SPI-NAND changes:
- define macros for page-read ops with three-byte addresses
- add support for two-byte device IDs and then for GigaDevice
GD5F1GQ4UFxxG
- add initial support for Paragon PN26G0xA
- handle the case where the last page read has bitflips
SPI-NOR core changes:
- add support for the mt25ql02g and w25q16jv flashes
- print error in case of jedec read id fails
- is25lp256: add post BFPT fix to correct the addr_width
SPI NOR controller drivers changes:
- intel-spi: Add support for Intel Elkhart Lake SPI serial flash
- smt32: remove the driver as the driver was replaced by spi-stm32-qspi.c
- cadence-quadspi: add reset control"
* tag 'mtd/for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux: (60 commits)
mtd: concat: implement _is_locked mtd operation
mtd: concat: refactor concat_lock/concat_unlock
mtd: abi: do not use C++ style comments in uapi header
mtd: afs: remove unneeded NULL check
mtd: rawnand: stm32_fmc2: increase DMA completion timeouts
mtd: rawnand: Use kzalloc() instead of kmalloc() and memset()
mtd: hyperbus: Add driver for TI's HyperBus memory controller
mtd: spinand: read returns badly if the last page has bitflips
mtd: spinand: Add initial support for Paragon PN26G0xA
mtd: rawnand: mtk: Re-license MTK NAND driver as Dual MIT/GPL
mtd: rawnand: gpmi: remove double assignment to block_size
dt-bindings: mtd: brcmnand: Add brcmnand, brcmnand-v7.3 support
mtd: rawnand: brcmnand: Add support for v7.3 controller
mtd: rawnand: brcmnand: Refactored code to introduce helper functions
mtd: rawnand: brcmnand: When oops in progress use pio and interrupt polling
mtd: Add flag to indicate panic_write
mtd: rawnand: Add Macronix NAND read retry support
mtd: onenand: Avoid fall-through warnings
mtd: spinand: Add support for GigaDevice GD5F1GQ4UFxxG
mtd: spinand: Add support for two-byte device IDs
...
SPI-NOR core changes:
- add support for the mt25ql02g and w25q16jv flashes
- print error in case of jedec read id fails
- is25lp256: add post BFPT fix to correct the addr_width
SPI NOR controller drivers changes:
- intel-spi: Add support for Intel Elkhart Lake SPI serial flash
- smt32: remove the driver as the driver was replaced by spi-stm32-qspi.c
- cadence-quadspi: add reset control
NAND core changes:
- use longest matching pattern in ->exec_op() default parser
- export NAND operation tracer
- add flag to indicate panic_write in MTD
- use kzalloc() instead of kmalloc() and memset()
Raw NAND controller drivers changes:
- brcmnand:
* fix BCH ECC layout for large page NAND parts
* fallback to detected ecc-strength, ecc-step-size
* when oops in progress use pio and interrupt polling
* code refactor code to introduce helper functions
* add support for v7.3 controller
- FSMC:
* use nand_op_trace for operation tracing
- GPMI:
* move all driver code into single file
* various cleanups (including dmaengine changes)
* use runtime PM to manage clocks
* implement exec_op
- MTK:
* correct low level time calculation of r/w cycle
* improve data sampling timing for read cycle
* add validity check for CE# pin setting
* fix wrongly assigned OOB buffer pointer issue
* re-license MTK NAND driver as Dual MIT/GPL
- STM32:
* manage the get_irq error case
* increase DMA completion timeouts
Raw NAND chips drivers changes:
- Macronix: add read-retry support
Onenand driver changes:
- add support for 8Gb datasize chips
- avoid fall-through warnings
SPI-NAND changes:
- define macros for page-read ops with three-byte addresses
- add support for two-byte device IDs and then for GigaDevice
GD5F1GQ4UFxxG
- add initial support for Paragon PN26G0xA
- handle the case where the last page read has bitflips
Added brcm,brcmnand-v7.3 as possible compatible string to support
brcmnand controller v7.3.
Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
nand-ecc-strength and nand-ecc-step-size can be made optional as
brcmnand driver can support using raw NAND layer detected values.
Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
The QSPI module can have an optional reset signals that will hold the
module in a reset state.
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
There's a new driver using the SPI memory interface of the
SPI framework at spi/spi-stm32-qspi.c, which can be used
together with m25p80.c to replace the functionality of
this SPI NOR driver.
The "new" driver uses the same dt properties and not affects
the legacy compatibility.
Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
nand-controller.yaml replaced nand.txt however the references to it were
not updated. This change updates these references wherever it appears in
bindings documentation.
Fixes: 212e496935 ("dt-bindings: mtd: Add YAML schemas for the generic NAND options")
Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Describe how to use the BCM963XX ImageTag format in a mixed flash layout
environment.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Add binding documentation for the standard CFE based BCM963XX flash
layout, found in most devices using a BCM63XX SoC with NOR flash.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
The A23/A33 NAND controller is slightly different than the A10+ ones,
eg. DMA handling is a bit different and a few register offsets
changed.
Introduce a new compatible to represent this version of the IP.
Also append '-controller' to the new compatible (which is required for
new compatibles) as this is describing a NAND controller and not a
NAND chip.
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
The NAND chips in MTD have a bunch of generic options that are needed in a
device tree. Add a YAML schemas for those.
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Currently, this driver sticks to the legacy NAND model because it was
upstreamed before commit 2d472aba15 ("mtd: nand: document the NAND
controller/NAND chip DT representation"). However, relying on the
dummy_controller is already deprecated.
Switch over to the new controller/chip representation.
The struct denali_nand_info has been split into denali_controller
and denali_chip, to contain the controller data, per-chip data,
respectively.
One problem is, this commit changes the DT binding. So, as always,
the backward compatibility must be taken into consideration.
In the new binding, the controller node expects
#address-cells = <1>;
#size-cells = <0>;
... since the child nodes represent NAND chips.
In the old binding, the controller node may have subnodes, but they
are MTD partitions.
The denali_dt_is_legacy_binding() exploits it to distinguish old/new
platforms.
Going forward, the old binding is only allowed for existing DT files.
I updated the binding document.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
The 'ingenic,bch-controller' property is now deprecated and the
'ecc-engine' property should be used instead.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
The JZ4740 ECC hardware is not BCH but Reed-Solomon, so it makes more
sense to use the more generic ECC term.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Add compatible strings to probe the jz4780-nand and jz4780-bch drivers
from devicetree on the JZ4725B and JZ4740 SoCs from Ingenic.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Pull spi updates from Mark Brown:
"A fairly quiet release for SPI, the biggest thing is the conversion to
use GPIO descriptors which is now 90% done but still needs some
stragglers converting.
Summary:
- Support for inter-word delays
- Conversion of the core and most drivers to use GPIO descriptors for
GPIO controlled chip selects
- New drivers for NXP FlexSPI and QuadSPI, SiFive and Spreadtrum"
* tag 'spi-v5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: (104 commits)
spi: sh-msiof: Restrict bits per word to 8/16/24/32 on R-Car Gen2/3
spi: sifive: Remove redundant dev_err call in sifive_spi_probe()
spi: sifive: Remove spi_master_put in sifive_spi_remove()
spi: spi-gpio: fix SPI_CS_HIGH capability
spi: pxa2xx: Setup maximum supported DMA transfer length
spi: sifive: Add driver for the SiFive SPI controller
spi: sifive: Add DT documentation for SiFive SPI controller
spi: sprd: Add a prefix for SPI DMA channel macros
spi: sprd: spi: sprd: Add DMA mode support
dt-bindings: spi: Add the DMA properties for the SPI dma mode
spi: sprd: Add the SPI irq function for the SPI DMA mode
dt-bindings: spi: imx: Add an entry for the i.MX8QM compatible
spi: use gpio[d]_set_value_cansleep for setting chipselect GPIO
spi: gpio: Advertise support for SPI_CS_HIGH
spi: sh-msiof: Replace spi_master by spi_controller
spi: sh-hspi: Replace spi_master by spi_controller
spi: rspi: Replace spi_master by spi_controller
spi: atmel-quadspi: add support for sam9x60 qspi controller
dt-bindings: spi: atmel-quadspi: QuadSPI driver for Microchip SAM9X60
spi: atmel-quadspi: add support for named peripheral clock
...
NAND core changes:
- Fourth batch of fixes/cleanup to the raw NAND core impacting various
controller drivers (Sunxi, Marvell, MTK, TMIO, OMAP2).
- Checking the return code of nand_reset() and nand_readid_op().
- Removing ->legacy.erase and single_erase().
- Simplifying the locking.
- Several implicit fall through annotations.
Raw NAND controllers drivers changes:
- Fixing various possible object reference leaks (MTK, JZ4780, Atmel).
- ST:
* Adding support for STM32 FMC2 NAND flash controller.
- Meson:
* Adding support for Amlogic NAND flash controller.
- Denali:
* Several cleanup patches.
- Sunxi:
* Several cleanup patches.
- FSMC:
* Disabling NAND on remove().
* Resetting NAND timings on resume().
SPI-NAND drivers changes:
- Toshiba:
* Adding support for all Toshiba products.
- Macronix:
* Fixing ECC status read.
- Gigadevice:
* Adding support for GD5F1GQ4UExxG.
AM654 SoC has Cadence Octal SPI controller, which is similar to Cadence
QSPI controller but supports Octal IO(x8 data lines) and Double Data
Rate(DDR) mode. Add new compatible to support OSPI controller on TI's
AM654 SoCs.
Signed-off-by: Vignesh R <vigneshr@ti.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Move the documentation of the old SPI NOR driver to the place of the new
SPI memory interface based driver.
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Pull spi updates from Mark Brown:
"The main thing this release has been a lot of work on the integration
with SPI NOR flashes, there's been some specific support for a while
for controller features designed to make them perform better but it's
not worked out as well as hoped so the interface has been redesigned
in a way that will hopefully do better - it's already been adopted by
a number of additional controllers so things are looking good.
Otherwise most of the work has been driver specific:
- Support for better integration with NOR flashes from Boris
Brezillon and Yogesh Narayan Gaur plus usage of it in several
drivers.
- A big cleanup of the Rockchip driver from Emil Renner Berthing.
- Lots of performance improvements for bcm2835 from Lukas Wunner.
- Slave mode support for pxa2xx from Lubomir Rintel.
- Support for Macronix MXIC, Mediatek MT7629 and MT8183, NPCM PSPI,
and Renesas r8a77470"
* tag 'spi-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: (90 commits)
spi: sh-msiof: Reduce the number of times write to and perform the transmission from FIFO
spi: sh-msiof: Add r8a774c0 support
doc: lpspi: Document DT bindings for LPSPI slave mode
spi: lpspi: Let watermark change with send data length
spi: lpspi: Add slave mode support
spi: lpspi: Replace all "master" with "controller"
spi: imx: drop useless member speed_hz from driver data struct
spi: imx: rename config callback and add useful parameters
spi: imx: style fixes
spi: imx: mx51-ecspi: Move some initialisation to prepare_message hook.
spi: imx: add a device specific prepare_message callback
mtd: atmel-quadspi: disallow building on ebsa110
spi: Update NPCM PSPI controller documentation
spi: npcm: Modify pspi send function
spi: Use of_node_name_eq for node name comparisons
spi: dw-mmio: add ACPI support
spi: bcm2835: Synchronize with callback on DMA termination
spi: bcm2835: Speed up FIFO access if fill level is known
spi: bcm2835: Polish transfer of DMA prologue
spi: spi-mem: add support for octal mode I/O data transfer
...
Pull SPI NOR updates from Boris Brezillon:
"
Core changes:
- Apply reset hacks only when reset is explicitly marked as broken in
the DT
Driver changes:
- Minor cleanup/fixes in the m25p80 driver
- Release flash_np in the nxp-spifi driver
- Add suspend/resume hooks to the atmel-quadspi driver
- Include gpio/consumer.h instead of gpio.h in the atmel-quadspi driver
- Use %pK instead of %p in the stm32-quadspi driver
- Improve timeout handling in the cadence-quadspi driver
- Use mtd_device_register() instead of mtd_device_parse_register() in
the intel-spi driver
"
Pull NAND updates from Miquel Raynal:
"
NAND core changes:
- Add the SPI-NAND framework.
- Create a helper to find the best ECC configuration.
- Create NAND controller operations.
- Allocate dynamically ONFI parameters structure.
- Add defines for ONFI version bits.
- Add manufacturer fixup for ONFI parameter page.
- Add an option to specify NAND chip as a boot device.
- Add Reed-Solomon error correction algorithm.
- Better name for the controller structure.
- Remove unused caller_is_module() definition.
- Make subop helpers return unsigned values.
- Expose _notsupp() helpers for raw page accessors.
- Add default values for dynamic timings.
- Kill the chip->scan_bbt() hook.
- Rename nand_default_bbt() into nand_create_bbt().
- Start to clean the nand_chip structure.
- Remove stale prototype from rawnand.h.
Raw NAND controllers drivers changes:
- Qcom: structuring cleanup.
- Denali: use core helper to find the best ECC configuration.
- Possible build of almost all drivers by adding a dependency on
COMPILE_TEST for almost all of them in Kconfig, implies various
fixes, Kconfig cleanup, GPIO headers inclusion cleanup, and even
changes in sparc64 and ia64 architectures.
- Clean the ->probe() functions error path of a lot of drivers.
- Migrate all drivers to use nand_scan() instead of
nand_scan_ident()/nand_scan_tail() pair.
- Use mtd_device_register() where applicable to simplify the code.
- Marvell:
* Handle on-die ECC.
* Better clocks handling.
* Remove bogus comment.
* Add suspend and resume support.
- Tegra: add NAND controller driver.
- Atmel:
* Add module param to avoid using dma.
* Drop Wenyou Yang from MAINTAINERS.
- Denali: optimize timings handling.
- FSMC: Stop using chip->read_buf().
- FSL:
* Switch to SPDX license tag identifiers.
* Fix qualifiers in MXC init functions.
Raw NAND chip drivers changes:
- Micron:
* Add fixup for ONFI revision.
* Update ecc_stats.corrected.
* Make ECC activation stateful.
* Avoid enabling/disabling ECC when it can't be disabled.
* Get the actual number of bitflips.
* Allow forced on-die ECC.
* Support 8/512 on-die ECC.
* Fix on-die ECC detection logic.
- Hynix:
* Fix decoding the OOB size on H27UCG8T2BTR.
* Use ->exec_op() in hynix_nand_reg_write_op().
"
Commit 59b356ffd0 ("mtd: m25p80: restore the status of SPI flash when
exiting") is the latest from a long history of attempts to add reboot
handling to handle stateful addressing modes on SPI flash. Some prior
mostly-related discussions:
http://lists.infradead.org/pipermail/linux-mtd/2013-March/046343.html
[PATCH 1/3] mtd: m25p80: utilize dedicated 4-byte addressing commands
http://lists.infradead.org/pipermail/barebox/2014-September/020682.html
[RFC] MTD m25p80 3-byte addressing and boot problem
http://lists.infradead.org/pipermail/linux-mtd/2015-February/057683.html
[PATCH 2/2] m25p80: if supported put chip to deep power down if not used
Previously, attempts to add reboot-time software reset handling were
rejected, but the latest attempt was not.
Quick summary of the problem:
Some systems (e.g., boot ROM or bootloader) assume that they can read
initial boot code from their SPI flash using 3-byte addressing. If the
flash is left in 4-byte mode after reset, these systems won't boot. The
above patch provided a shutdown/remove hook to attempt to reset the
addressing mode before we reboot. Notably, this patch misses out on
huge classes of unexpected reboots (e.g., crashes, watchdog resets).
Unfortunately, it is essentially impossible to solve this problem 100%:
if your system doesn't know how to reset the SPI flash to power-on
defaults at initialization time, no amount of software can really rescue
you -- there will always be a chance of some unexpected reset that
leaves your flash in an addressing mode that your boot sequence didn't
expect.
While it is not directly harmful to perform hacks like the
aforementioned commit on all 4-byte addressing flash, a
properly-designed system should not need the hack -- and in fact,
providing this hack may mask the fact that a given system is indeed
broken. So this patch attempts to apply this unsound hack more narrowly,
providing a strong suggestion to developers and system designers that
this is truly a hack. With luck, system designers can catch their errors
early on in their development cycle, rather than applying this hack long
term. But apparently enough systems are out in the wild that we still
have to provide this hack.
Document a new device tree property to denote systems that do not have a
proper hardware (or software) reset mechanism, and apply the hack (with
a loud warning) only in this case.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
