nvmem: core: update raw_len if the bit reading is required

If NVMEM cell uses bit offset or specifies bit truncation, update
raw_len manually (following the cell->bytes update), ensuring that the
NV

nvmem: core: update raw_len if the bit reading is required

If NVMEM cell uses bit offset or specifies bit truncation, update
raw_len manually (following the cell->bytes update), ensuring that the
NVMEM access is still word-aligned.

Signed-off-by: Dmitry Baryshkov <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

nvmem: core: verify cell's raw_len

Check that the NVMEM cell's raw_len is a aligned to word_size. Otherwise
Otherwise drivers might face incomplete read while accessing the last
part of the NVMEM ce

nvmem: core: verify cell's raw_len

Check that the NVMEM cell's raw_len is a aligned to word_size. Otherwise
Otherwise drivers might face incomplete read while accessing the last
part of the NVMEM cell.

Signed-off-by: Dmitry Baryshkov <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

nvmem: core: fix bit offsets of more than one byte

If the NVMEM specifies a stride to access data, reading particular cell
might require bit offset that is bigger than one byte. Rework NVMEM core
co

nvmem: core: fix bit offsets of more than one byte

If the NVMEM specifies a stride to access data, reading particular cell
might require bit offset that is bigger than one byte. Rework NVMEM core
code to support bit offsets of more than 8 bits.

Signed-off-by: Dmitry Baryshkov <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

nvmem: core: improve range check for nvmem_cell_write()

When __nvmem_cell_entry_write() is called for an nvmem cell that does
not need bit shifting, it requires that the len parameter exactly
matche

nvmem: core: improve range check for nvmem_cell_write()

When __nvmem_cell_entry_write() is called for an nvmem cell that does
not need bit shifting, it requires that the len parameter exactly
matches the nvmem cell size. However, when the nvmem cell has a nonzero
bit_offset, it was skipping this check.

Accepting values of len larger than the cell size results in
nvmem_cell_prepare_write_buffer() trying to write past the end of a heap
buffer that it allocates. Add a check to avoid that problem and instead
return -EINVAL when len doesn't match the number of bits expected by the
nvmem cell when bit_offset is nonzero.

This check uses cell->nbits in order to allow providing the smaller size
to cells that are shifted into another byte by bit_offset. For example,
a cell with nbits=8 and nonzero bit_offset would have bytes=2 but should
accept a 1-byte write here, although no current callers depend on this.

Fixes: 69aba7948cbe ("nvmem: Add a simple NVMEM framework for consumers")
Cc: [email protected]
Signed-off-by: Jennifer Berringer <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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nvmem: core: constify 'struct bin_attribute'

The sysfs core now allows instances of 'struct bin_attribute' to be
moved into read-only memory. Make use of that to protect them against
accidental or m

nvmem: core: constify 'struct bin_attribute'

The sysfs core now allows instances of 'struct bin_attribute' to be
moved into read-only memory. Make use of that to protect them against
accidental or malicious modifications.

Also adapt the dynamic sysfs cell logic to handle the const attributes.

Signed-off-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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nvmem: core: Check read_only flag for force_ro in bin_attr_nvmem_write()

The bin_attr_nvmem_write() must check the read_only flag and block
writes on read-only devices, now that a nvmem device can b

nvmem: core: Check read_only flag for force_ro in bin_attr_nvmem_write()

The bin_attr_nvmem_write() must check the read_only flag and block
writes on read-only devices, now that a nvmem device can be switched
between read-write and read-only mode at runtime using the force_ro
attribute. Add the missing check.

Fixes: 9d7eb234ac7a ("nvmem: core: Implement force_ro sysfs attribute")
Cc: [email protected]
Signed-off-by: Marek Vasut <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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sysfs: treewide: constify attribute callback of bin_is_visible()

The is_bin_visible() callbacks should not modify the struct
bin_attribute passed as argument.
Enforce this by marking the argument as

sysfs: treewide: constify attribute callback of bin_is_visible()

The is_bin_visible() callbacks should not modify the struct
bin_attribute passed as argument.
Enforce this by marking the argument as const.

As there are not many callback implementers perform this change
throughout the tree at once.

Signed-off-by: Thomas Weißschuh <[email protected]>
Acked-by: Martin K. Petersen <[email protected]>
Acked-by: Jason Gunthorpe <[email protected]>
Acked-by: Ira Weiny <[email protected]>
Acked-by: Krzysztof Wilczyński <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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nvmem: core: calculate bin_attribute size through bin_size()

Stop abusing the is_bin_visible() callback to calculate the attribute
size. Instead use the new, dedicated bin_size() one.

Signed-off-by

nvmem: core: calculate bin_attribute size through bin_size()

Stop abusing the is_bin_visible() callback to calculate the attribute
size. Instead use the new, dedicated bin_size() one.

Signed-off-by: Thomas Weißschuh <[email protected]>
Acked-by: Krzysztof Wilczyński <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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nvmem: Correct some typos in comments

Fixed some confusing typos that were currently identified with codespell,
the details are as follows:

-in the code comments:
drivers/nvmem/brcm_nvram.c:25: und

nvmem: Correct some typos in comments

Fixed some confusing typos that were currently identified with codespell,
the details are as follows:

-in the code comments:
drivers/nvmem/brcm_nvram.c:25: underlaying ==> underlying
drivers/nvmem/core.c:1250: alredy ==> already
drivers/nvmem/core.c:1268: alredy ==> already
drivers/nvmem/lpc18xx_otp.c:24: reseverd ==> reserved
drivers/nvmem/microchip-otpc.c:159: devide ==> divide

Signed-off-by: Shen Lichuan <[email protected]>
Acked-by: Vladimir Zapolskiy <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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nvmem: Fix return type of devm_nvmem_device_get() in kerneldoc

devm_nvmem_device_get() returns an nvmem device, not an nvmem cell.

Fixes: e2a5402ec7c6d044 ("nvmem: Add nvmem_device based consumer a

nvmem: Fix return type of devm_nvmem_device_get() in kerneldoc

devm_nvmem_device_get() returns an nvmem device, not an nvmem cell.

Fixes: e2a5402ec7c6d044 ("nvmem: Add nvmem_device based consumer apis.")
Cc: stable <[email protected]>
Signed-off-by: Geert Uytterhoeven <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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nvmem: core: Implement force_ro sysfs attribute

Implement "force_ro" sysfs attribute to allow users to set read-write
devices as read-only and back to read-write from userspace. The choice
of the na

nvmem: core: Implement force_ro sysfs attribute

Implement "force_ro" sysfs attribute to allow users to set read-write
devices as read-only and back to read-write from userspace. The choice
of the name is based on MMC core 'force_ro' attribute.

This solves a situation where an AT24 I2C EEPROM with GPIO based nWP
signal may have to be occasionally updated. Such I2C EEPROM device is
usually set as read-only during most of the regular system operation,
but in case it has to be updated in a controlled manner, it could be
unlocked using this new "force_ro" sysfs attribute and then re-locked
again.

The "read-only" DT property and config->read_only configuration is
respected and is used to set default state of the device, read-only
or read-write, for devices which do implement .reg_write function.
For devices which do not implement .reg_write function, the device
is unconditionally read-only and the "force_ro" attribute is not
visible.

Signed-off-by: Marek Vasut <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

nvmem: Use sysfs_emit() for type attribute

Use sysfs_emit() instead of sprintf() to follow best practice per
Documentation/filesystems/sysfs.rst
"
show() should only use sysfs_emit()...
"

Signed-of

nvmem: Use sysfs_emit() for type attribute

Use sysfs_emit() instead of sprintf() to follow best practice per
Documentation/filesystems/sysfs.rst
"
show() should only use sysfs_emit()...
"

Signed-off-by: Marek Vasut <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

nvmem: core: drop unnecessary range checks in sysfs callbacks

The same checks have already been done in sysfs_kf_bin_write() and
sysfs_kf_bin_read() just before the callbacks are invoked.

Signed-of

nvmem: core: drop unnecessary range checks in sysfs callbacks

The same checks have already been done in sysfs_kf_bin_write() and
sysfs_kf_bin_read() just before the callbacks are invoked.

Signed-off-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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nvmem: core: remove global nvmem_cells_group

nvmem_cells_groups is a global variable that is also mutated.
This is complicated and error-prone.

Instead use a normal stack variable.

Signed-off-by:

nvmem: core: remove global nvmem_cells_group

nvmem_cells_groups is a global variable that is also mutated.
This is complicated and error-prone.

Instead use a normal stack variable.

Signed-off-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

nvmem: core: add single sysfs group

The sysfs core provides a function to easily register a single group.
Use it and remove the now unnecessary nvmem_cells_groups array.

Signed-off-by: Thomas Weißs

nvmem: core: add single sysfs group

The sysfs core provides a function to easily register a single group.
Use it and remove the now unnecessary nvmem_cells_groups array.

Signed-off-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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nvmem: core: limit cell sysfs permissions to main attribute ones

The cell sysfs attribute should not provide more access to the nvmem
data than the main attribute itself.
For example if nvme_config:

nvmem: core: limit cell sysfs permissions to main attribute ones

The cell sysfs attribute should not provide more access to the nvmem
data than the main attribute itself.
For example if nvme_config::root_only was set, the cell attribute
would still provide read access to everybody.

Mask out permissions not available on the main attribute.

Fixes: 0331c611949f ("nvmem: core: Expose cells through sysfs")
Cc: [email protected]
Signed-off-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

nvmem: core: only change name to fram for current attribute

bin_attr_nvmem_eeprom_compat is the template from which all future
compat attributes are created.
Changing it means to change all subsquen

nvmem: core: only change name to fram for current attribute

bin_attr_nvmem_eeprom_compat is the template from which all future
compat attributes are created.
Changing it means to change all subsquent compat attributes, too.

Instead only use the "fram" name for the currently registered attribute.

Fixes: fd307a4ad332 ("nvmem: prepare basics for FRAM support")
Cc: [email protected]
Signed-off-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

nvmem: core: switch to use device_add_groups()

devm_device_add_groups() is being removed from the kernel, so move the
nvmem driver to use device_add_groups() instead. The logic is
identical, when t

nvmem: core: switch to use device_add_groups()

devm_device_add_groups() is being removed from the kernel, so move the
nvmem driver to use device_add_groups() instead. The logic is
identical, when the device is removed the driver core will properly
clean up and remove the groups, and the memory used by the attribute
groups will be freed because it was created with dev_* calls, so this is
functionally identical overall.

Cc: Srinivas Kandagatla <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

nvmem: core: Print error on wrong bits DT property

The algorithms in nvmem core are built with the constraint that
bit_offset < 8. If bit_offset is greater the results are wrong. Print an
error if t

nvmem: core: Print error on wrong bits DT property

The algorithms in nvmem core are built with the constraint that
bit_offset < 8. If bit_offset is greater the results are wrong. Print an
error if the devicetree 'bits' property is outside of the valid range
and abort parsing.

Signed-off-by: Markus Schneider-Pargmann <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

nvmem: include bit index in cell sysfs file name

Creating sysfs files for all Cells caused a boot failure for linux-6.8-rc1 on
Apple M1, which (in downstream dts files) has multiple nvmem cells that

nvmem: include bit index in cell sysfs file name

Creating sysfs files for all Cells caused a boot failure for linux-6.8-rc1 on
Apple M1, which (in downstream dts files) has multiple nvmem cells that use the
same byte address. This causes the device probe to fail with

[ 0.605336] sysfs: cannot create duplicate filename '/devices/platform/soc@200000000/2922bc000.efuse/apple_efuses_nvmem0/cells/efuse@a10'
[ 0.605347] CPU: 7 PID: 1 Comm: swapper/0 Tainted: G S 6.8.0-rc1-arnd-5+ #133
[ 0.605355] Hardware name: Apple Mac Studio (M1 Ultra, 2022) (DT)
[ 0.605362] Call trace:
[ 0.605365] show_stack+0x18/0x2c
[ 0.605374] dump_stack_lvl+0x60/0x80
[ 0.605383] dump_stack+0x18/0x24
[ 0.605388] sysfs_warn_dup+0x64/0x80
[ 0.605395] sysfs_add_bin_file_mode_ns+0xb0/0xd4
[ 0.605402] internal_create_group+0x268/0x404
[ 0.605409] sysfs_create_groups+0x38/0x94
[ 0.605415] devm_device_add_groups+0x50/0x94
[ 0.605572] nvmem_populate_sysfs_cells+0x180/0x1b0
[ 0.605682] nvmem_register+0x38c/0x470
[ 0.605789] devm_nvmem_register+0x1c/0x6c
[ 0.605895] apple_efuses_probe+0xe4/0x120
[ 0.606000] platform_probe+0xa8/0xd0

As far as I can tell, this is a problem for any device with multiple cells on
different bits of the same address. Avoid the issue by changing the file name
to include the first bit number.

Fixes: 0331c611949f ("nvmem: core: Expose cells through sysfs")
Link: https://github.com/AsahiLinux/linux/blob/bd0a1a7d4/arch/arm64/boot/dts/apple/t600x-dieX.dtsi#L156
Cc: <[email protected]>
Cc: Miquel Raynal <[email protected]>
Cc: Rafał Miłecki <[email protected]>
Cc: Chen-Yu Tsai <[email protected]>
Cc: Srinivas Kandagatla <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: <[email protected]>
Cc: Sven Peter <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Reviewed-by: Eric Curtin <[email protected]>
Reviewed-by: Miquel Raynal <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

nvmem: core: add nvmem_dev_size() helper

This is required by layouts that need to read whole NVMEM content. It's
especially useful for NVMEM devices without hardcoded layout (like
U-Boot environment

nvmem: core: add nvmem_dev_size() helper

This is required by layouts that need to read whole NVMEM content. It's
especially useful for NVMEM devices without hardcoded layout (like
U-Boot environment data block).

Signed-off-by: Rafał Miłecki <[email protected]>
Reviewed-by: Miquel Raynal <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

nvmem: drop nvmem_layout_get_match_data()

Thanks for layouts refactoring we now have "struct device" associated
with layout. Also its OF pointer points directly to the "nvmem-layout"
DT node.

All i

nvmem: drop nvmem_layout_get_match_data()

Thanks for layouts refactoring we now have "struct device" associated
with layout. Also its OF pointer points directly to the "nvmem-layout"
DT node.

All it takes to get match data is a generic of_device_get_match_data().

Signed-off-by: Rafał Miłecki <[email protected]>
Reviewed-by: Miquel Raynal <[email protected]>
Reviewed-by: Michael Walle <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

nvmem: layouts: refactor .add_cells() callback arguments

Simply pass whole "struct nvmem_layout" instead of single variables.
There is nothing in "struct nvmem_layout" that we have to hide from
layo

nvmem: layouts: refactor .add_cells() callback arguments

Simply pass whole "struct nvmem_layout" instead of single variables.
There is nothing in "struct nvmem_layout" that we have to hide from
layout drivers. They also access it during .probe() and .remove().

Thanks to this change:

1. API gets more consistent
All layouts drivers callbacks get the same argument

2. Layouts get correct device
Before this change NVMEM core code was passing NVMEM device instead
of layout device. That resulted in:
* Confusing prints
* Calling devm_*() helpers on wrong device
* Helpers like of_device_get_match_data() dereferencing NULLs

3. It gets possible to get match data
First of all nvmem_layout_get_match_data() requires passing "struct
nvmem_layout" which .add_cells() callback didn't have before this. It
doesn't matter much as it's rather useless now anyway (and will be
dropped).
What's more important however is that of_device_get_match_data() can
be used now thanks to owning a proper device pointer.

Signed-off-by: Rafał Miłecki <[email protected]>
Reviewed-by: Miquel Raynal <[email protected]>
Reviewed-by: Michael Walle <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

nvmem: core: Expose cells through sysfs

The binary content of nvmem devices is available to the user so in the
easiest cases, finding the content of a cell is rather easy as it is
just a matter of l

nvmem: core: Expose cells through sysfs

The binary content of nvmem devices is available to the user so in the
easiest cases, finding the content of a cell is rather easy as it is
just a matter of looking at a known and fixed offset. However, nvmem
layouts have been recently introduced to cope with more advanced
situations, where the offset and size of the cells is not known in
advance or is dynamic. When using layouts, more advanced parsers are
used by the kernel in order to give direct access to the content of each
cell, regardless of its position/size in the underlying
device. Unfortunately, these information are not accessible by users,
unless by fully re-implementing the parser logic in userland.

Let's expose the cells and their content through sysfs to avoid these
situations. Of course the relevant NVMEM sysfs Kconfig option must be
enabled for this support to be available.

Not all nvmem devices expose cells. Indeed, the .bin_attrs attribute
group member will be filled at runtime only when relevant and will
remain empty otherwise. In this case, as the cells attribute group will
be empty, it will not lead to any additional folder/file creation.

Exposed cells are read-only. There is, in practice, everything in the
core to support a write path, but as I don't see any need for that, I
prefer to keep the interface simple (and probably safer). The interface
is documented as being in the "testing" state which means we can later
add a write attribute if though relevant.

Signed-off-by: Miquel Raynal <[email protected]>
Tested-by: Rafał Miłecki <[email protected]>
Tested-by: Chen-Yu Tsai <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

nvmem: core: Rework layouts to become regular devices

Current layout support was initially written without modules support in
mind. When the requirement for module support rose, the existing base
wa

nvmem: core: Rework layouts to become regular devices

Current layout support was initially written without modules support in
mind. When the requirement for module support rose, the existing base
was improved to adopt modularization support, but kind of a design flaw
was introduced. With the existing implementation, when a storage device
registers into NVMEM, the core tries to hook a layout (if any) and
populates its cells immediately. This means, if the hardware description
expects a layout to be hooked up, but no driver was provided for that,
the storage medium will fail to probe and try later from
scratch. Even if we consider that the hardware description shall be
correct, we could still probe the storage device (especially if it
contains the rootfs).

One way to overcome this situation is to consider the layouts as
devices, and leverage the native notifier mechanism. When a new NVMEM
device is registered, we can populate its nvmem-layout child, if any,
and wait for the matching to be done in order to get the cells (the
waiting can be easily done with the NVMEM notifiers). If the layout
driver is compiled as a module, it should automatically be loaded. This
way, there is no strong order to enforce, any NVMEM device creation
or NVMEM layout driver insertion will be observed as a new event which
may lead to the creation of additional cells, without disturbing the
probes with costly (and sometimes endless) deferrals.

In order to achieve that goal we create a new bus for the nvmem-layouts
with minimal logic to match nvmem-layout devices with nvmem-layout
drivers. All this infrastructure code is created in the layouts.c file.

Signed-off-by: Miquel Raynal <[email protected]>
Tested-by: Rafał Miłecki <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...