kernel/linux.git/drivers/nvmem/core.c, branch v4.14.85

nvmem: Don't let a NULL cell_id for nvmem_cell_get() crash us

2018-08-24T11:09:14+00:00

[ Upstream commit 87ed1405ef09d29a14df43295f7b6a93b63bfe6e ] In commit ca04d9d3e1b1 ("phy: qcom-qusb2: New driver for QUSB2 PHY on Qcom chips") you can see a call like: devm_nvmem_cell_get(dev, NULL); Note that the cell ID passed to the function is NULL. This is because the qcom-qusb2 driver is expected to work only on systems where the PHY node is hooked up via device-tree and is nameless. This works OK for the most part. The first thing nvmem_cell_get() does is to call of_nvmem_cell_get() and there it's documented that a NULL name is fine. The problem happens when the call to of_nvmem_cell_get() returns -EINVAL. In such a case we'll fall back to nvmem_cell_get_from_list() and eventually might (if nvmem_cells isn't an empty list) crash with something that looks like: strcmp nvmem_find_cell __nvmem_device_get nvmem_cell_get_from_list nvmem_cell_get devm_nvmem_cell_get qusb2_phy_probe There are several different ways we could fix this problem: One could argue that perhaps the qcom-qusb2 driver should be changed to use of_nvmem_cell_get() which is allowed to have a NULL name. In that case, we'd need to add a patche to introduce devm_of_nvmem_cell_get() since the qcom-qusb2 driver is using devm managed resources. One could also argue that perhaps we could just add a name to qcom-qusb2. That would be OK but I believe it effectively changes the device tree bindings, so maybe it's a no-go. In this patch I have chosen to fix the problem by simply not crashing when a NULL cell_id is passed to nvmem_cell_get(). NOTE: that for the qcom-qusb2 driver the "nvmem-cells" property is defined to be optional and thus it's expected to be a common case that we would hit this crash and this is more than just a theoretical fix. Fixes: ca04d9d3e1b1 ("phy: qcom-qusb2: New driver for QUSB2 PHY on Qcom chips") Signed-off-by: Douglas Anderson Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

nvmem: properly handle returned value nvmem_reg_read

2018-08-03T05:50:34+00:00

[ Upstream commit 50808bfcc14b854775a9f1d0abe3dac2babcf5c3 ] Function nvmem_reg_read can return a non zero value indicating an error. This returned value must be read and error propagated to nvmem_cell_prepare_write_buffer. Silence the following gcc warning (W=1): drivers/nvmem/core.c:1093:9: warning: variable 'rc' set but not used [-Wunused-but-set-variable] Signed-off-by: Mathieu Malaterre Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

nvmem: add missing of_node_put() in of_nvmem_cell_get()

2017-09-18T14:12:26+00:00

of_get_next_parent() increments the refcount of the returned node. It should be put when done. Signed-off-by: Masahiro Yamada Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman

nvmem: core: return EFBIG on out-of-range write

2017-09-18T14:12:26+00:00

When writing data that exceeds the nvmem size to a nvmem sysfs file using the sh redirection operator >, the shell hangs, trying to write the out-of-range bytes endlessly. Fix the problem by returning EFBIG described in man 2 write. Similar change was done for binary sysfs files on commit 0936896056365349afa867c16e9f9100a6707cbf Signed-off-by: Guy Shapiro Cc: linux-api@vger.kernel.org Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman

nvmem: core: remove unneeded NULL check

2017-08-28T15:33:23+00:00

"p" is the list iterator so it can't be NULL. Static checkers complain about this unnecessary check because we dereference the list iterator to get the next item in the list so we'd be in trouble if it really was NULL. I have removed the check. Signed-off-by: Dan Carpenter Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman

nvmem: core: Add nvmem_cell_read_u32

2017-08-28T15:33:23+00:00

This function does a quick and easy read of an u32 value without any kind of resource management code on the consumer side. Signed-off-by: Leonard Crestez Reviewed-by: Shawn Guo Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman

nvmem: Convert to using %pOF instead of full_name

2017-08-28T15:33:22+00:00

Now that we have a custom printf format specifier, convert users of full_name to use %pOF instead. This is preparation to remove storing of the full path string for each node. Signed-off-by: Rob Herring Cc: Srinivas Kandagatla Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman

nvmem: core: add locking to nvmem_find_cell

2017-06-09T10:08:27+00:00

Adding entries to nvmem_cells and deleting entries from it is protected by nvmem_cells_mutex. Therefore this mutex should also protect iterating over the list. Signed-off-by: Heiner Kallweit Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman

nvmem: core: Call put_device() in nvmem_unregister()

2017-06-09T10:08:27+00:00

Call put_device() in nvmem_unregister() to make sure nvmem_release gets called freeing up allocated resources. Cc: cphealy@gmail.com Cc: Srinivas Kandagatla Cc: Maxime Ripard Signed-off-by: Andrey Smirnov Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman

nvmem: core: fix leaks on registration errors

2017-06-09T10:08:27+00:00

Make sure to deregister and release the nvmem device and underlying memory on registration errors. Note that the private data must be freed using put_device() once the struct device has been initialised. Also note that there's a related reference leak in the deregistration function as reported by Mika Westerberg which is being fixed separately. Fixes: b6c217ab9be6 ("nvmem: Add backwards compatibility support for older EEPROM drivers.") Fixes: eace75cfdcf7 ("nvmem: Add a simple NVMEM framework for nvmem providers") Cc: stable # 4.3 Cc: Andrew Lunn Cc: Srinivas Kandagatla Cc: Mika Westerberg Signed-off-by: Johan Hovold Acked-by: Andrey Smirnov Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman