linux-stable.git/drivers/nvmem/core.c, branch linux-6.3.y

nvmem: core: return -ENOENT if nvmem cell is not found

2023-03-10T09:55:49+00:00

Prior to commit 5d8e6e6c10a3 ("nvmem: core: add an index parameter to
the cell") of_nvmem_cell_get() would return -ENOENT if the cell wasn't
found. Particularly, if of_property_match_string() returned -EINVAL,
that return code was passed as the index to of_parse_phandle(), which
then detected it as invalid and returned NULL. That led to an return
code of -ENOENT.

With the new code, the negative index will lead to an -EINVAL of
of_parse_phandle_with_optional_args() which pass straight to the
caller and break those who expect an -ENOENT.

Fix it by always returning -ENOENT.

Fixes: 5d8e6e6c10a3 ("nvmem: core: add an index parameter to the cell")
Reported-by: Alexander Stein 
Link: https://lore.kernel.org/r/2143916.GUh0CODmnK@steina-w/
Signed-off-by: Michael Walle 
Tested-by: Alexander Stein 
Signed-off-by: Srinivas Kandagatla 
Link: https://lore.kernel.org/r/20230310094845.139400-1-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman

nvmem: core: use nvmem_add_one_cell() in nvmem_add_cells_from_of()

2023-02-06T18:06:59+00:00

Convert nvmem_add_cells_from_of() to use the new nvmem_add_one_cell().
This will remove duplicate code and it will make it possible to add a
hook to a nvmem layout in between, which can change fields before the
cell is finally added.

Signed-off-by: Michael Walle 
Signed-off-by: Srinivas Kandagatla 
Link: https://lore.kernel.org/r/20230206134356.839737-17-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman

nvmem: core: add nvmem_add_one_cell()

2023-02-06T18:06:59+00:00

Add a new function to add exactly one cell. This will be used by the
nvmem layout drivers to add custom cells. In contrast to the
nvmem_add_cells(), this has the advantage that we don't have to assemble
a list of cells on runtime.

Signed-off-by: Michael Walle 
Signed-off-by: Srinivas Kandagatla 
Link: https://lore.kernel.org/r/20230206134356.839737-16-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman

nvmem: core: drop the removal of the cells in nvmem_add_cells()

2023-02-06T18:06:59+00:00

If nvmem_add_cells() fails, the whole nvmem_register() will fail
and the cells will then be removed anyway. This is a preparation
to introduce a nvmem_add_one_cell() which can then be used by
nvmem_add_cells().

This is then the same to what nvmem_add_cells_from_table() and
nvmem_add_cells_from_of() do.

Signed-off-by: Michael Walle 
Signed-off-by: Srinivas Kandagatla 
Link: https://lore.kernel.org/r/20230206134356.839737-15-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman

nvmem: core: add an index parameter to the cell

2023-02-06T18:06:59+00:00

Sometimes a cell can represend multiple values. For example, a base
ethernet address stored in the NVMEM can be expanded into multiple
discreet ones by adding an offset.

For this use case, introduce an index parameter which is then used to
distiguish between values. This parameter will then be passed to the
post process hook which can then use it to create different values
during reading.

At the moment, there is only support for the device tree path. You can
add the index to the phandle, e.g.

  &net {
          nvmem-cells = <&base_mac_address 2>;
          nvmem-cell-names = "mac-address";
  };

  &nvmem_provider {
          base_mac_address: base-mac-address@0 {
                  #nvmem-cell-cells = <1>;
                  reg = <0 6>;
          };
  };

Signed-off-by: Michael Walle 
Signed-off-by: Srinivas Kandagatla 
Link: https://lore.kernel.org/r/20230206134356.839737-13-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman

nvmem: core: remove spurious white space

2023-02-06T18:06:58+00:00

Remove a spurious white space in for the ida_alloc() call.

Signed-off-by: Russell King (Oracle) 
Signed-off-by: Srinivas Kandagatla 
Link: https://lore.kernel.org/r/20230206134356.839737-8-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman

nvmem: core: fix return value

2023-01-28T13:39:11+00:00

Dan Carpenter points out that the return code was not set in commit
60c8b4aebd8e ("nvmem: core: fix cleanup after dev_set_name()"), but
this is not the only issue - we also need to zero wp_gpio to prevent
gpiod_put() being called on an error value.

Fixes: 560181d3ace6 ("nvmem: core: fix cleanup after dev_set_name()")
Cc: stable@vger.kernel.org
Reported-by: kernel test robot 
Reported-by: Dan Carpenter 
Signed-off-by: Russell King (Oracle) 
Signed-off-by: Srinivas Kandagatla 
Link: https://lore.kernel.org/r/20230127104015.23839-10-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman

nvmem: core: fix cell removal on error

2023-01-28T13:38:49+00:00

nvmem_add_cells() could return an error after some cells are already
added to the provider. In this case, the added cells are not removed.
Remove any registered cells if nvmem_add_cells() fails.

Fixes: fa72d847d68d7 ("nvmem: check the return value of nvmem_add_cells()")
Cc: stable@vger.kernel.org
Signed-off-by: Michael Walle 
Signed-off-by: Srinivas Kandagatla 
Link: https://lore.kernel.org/r/20230127104015.23839-9-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman

nvmem: core: fix device node refcounting

2023-01-28T13:38:44+00:00

In of_nvmem_cell_get(), of_get_next_parent() is used on cell_np. This
will decrement the refcount on cell_np, but cell_np is still used later
in the code. Use of_get_parent() instead and of_node_put() in the
appropriate places.

Fixes: 69aba7948cbe ("nvmem: Add a simple NVMEM framework for consumers")
Fixes: 7ae6478b304b ("nvmem: core: rework nvmem cell instance creation")
Cc: stable@vger.kernel.org
Signed-off-by: Michael Walle 
Signed-off-by: Srinivas Kandagatla 
Link: https://lore.kernel.org/r/20230127104015.23839-8-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman

nvmem: core: fix registration vs use race

2023-01-28T13:36:29+00:00

The i.MX6 CPU frequency driver sometimes fails to register at boot time
due to nvmem_cell_read_u32() sporadically returning -ENOENT.

This happens because there is a window where __nvmem_device_get() in
of_nvmem_cell_get() is able to return the nvmem device, but as cells
have been setup, nvmem_find_cell_entry_by_node() returns NULL.

The occurs because the nvmem core registration code violates one of the
fundamental principles of kernel programming: do not publish data
structures before their setup is complete.

Fix this by making nvmem core code conform with this principle.

Fixes: eace75cfdcf7 ("nvmem: Add a simple NVMEM framework for nvmem providers")
Cc: stable@vger.kernel.org
Signed-off-by: Russell King (Oracle) 
Signed-off-by: Srinivas Kandagatla 
Link: https://lore.kernel.org/r/20230127104015.23839-7-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman