linux-stable.git/drivers/base/regmap/regmap.c, branch linux-6.5.y

regmap: prevent noinc writes from clobbering cache

2023-11-20T10:57:21+00:00

[ Upstream commit 984a4afdc87a1fc226fd657b1cd8255c13d3fc1a ]

Currently, noinc writes are cached as if they were standard incrementing
writes, overwriting unrelated register values in the cache. Instead, we
want to cache the last value written to the register, as is done in the
accelerated noinc handler (regmap_noinc_readwrite).

Fixes: cdf6b11daa77 ("regmap: Add regmap_noinc_write API")
Signed-off-by: Ben Wolsieffer 
Link: https://lore.kernel.org/r/20231101142926.2722603-2-ben.wolsieffer@hefring.com
Signed-off-by: Mark Brown 
Signed-off-by: Sasha Levin

regmap: fix NULL deref on lookup

2023-10-25T10:16:10+00:00

commit c6df843348d6b71ea986266c12831cb60c2cf325 upstream.

Not all regmaps have a name so make sure to check for that to avoid
dereferencing a NULL pointer when dev_get_regmap() is used to lookup a
named regmap.

Fixes: e84861fec32d ("regmap: dev_get_regmap_match(): fix string comparison")
Cc: stable@vger.kernel.org      # 5.8
Cc: Marc Kleine-Budde 
Signed-off-by: Johan Hovold 
Link: https://lore.kernel.org/r/20231006082104.16707-1-johan+linaro@kernel.org
Signed-off-by: Mark Brown 
Signed-off-by: Greg Kroah-Hartman

regmap: Drop initial version of maximum transfer length fixes

2023-07-17T05:15:14+00:00

When problems were noticed with the register address not being taken
into account when limiting raw transfers with I2C devices we fixed this
in the core.  Unfortunately it has subsequently been realised that a lot
of buses were relying on the prior behaviour, partly due to unclear
documentation not making it obvious what was intended in the core.  This
is all more involved to fix than is sensible for a fix commit so let's
just drop the original fixes, a separate commit will fix the originally
observed problem in an I2C specific way

Fixes: 3981514180c9 ("regmap: Account for register length when chunking")
Fixes: c8e796895e23 ("regmap: spi-avmm: Fix regmap_bus max_raw_write")
Signed-off-by: Mark Brown 
Reviewed-by: Xu Yilun 
Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20230712-regmap-max-transfer-v1-1-80e2aed22e83@kernel.org
Signed-off-by: Mark Brown

regmap: Drop early readability check

2023-06-16T11:56:13+00:00

We have some drivers that have a use case for cached write only
registers, doing read/modify/writes on read only registers in order to
work more easily with bitfields.  Go back to trying the cache before we
check if we can read from the device.

Fixes: eab5abdeb79f0 ("regmap: Check for register readability before checking cache during read")
Reported-by: Konrad Dybcio 
Signed-off-by: Mark Brown 
Link: https://lore.kernel.org/r/20230615-regmap-drop-early-readability-v1-1-8135094362de@kernel.org
Signed-off-by: Mark Brown

regmap: Check for register readability before checking cache during read

2023-06-14T11:27:16+00:00

Ensure that we don't return a spurious cache hit for unreadable registers
(eg, with the flat cache which doesn't understand sparseness) by checking
for readability before we do a cache lookup.

Signed-off-by: Mark Brown 
Link: https://lore.kernel.org/r/20230613-b4-regmap-check-readability-before-cache-v1-1-b144c0b01ed9@kernel.org
Signed-off-by: Mark Brown

regmap: Add debugfs file for forcing field writes

2023-06-13T12:15:04+00:00

`_regmap_update_bits()` checks if the current register value differs
from the new value, and only writes to the register if they differ. When
testing hardware drivers, it might be desirable to always force a
register write, for example when writing to a `regmap_field`. This
enables and simplifies testing and verification of the hardware
interaction. For example, when using a hardware mock/simulation model,
one can then more easily verify that the driver makes the correct
expected register writes during certain events.

Add a bool variable `force_write_field` and a corresponding debugfs
entry to enable this. Since this feature could interfere with driver
operation, guard it with a macro.

Signed-off-by: Waqar Hameed 
Link: https://lore.kernel.org/r/pnd1qifa7sj.fsf@axis.com
Signed-off-by: Mark Brown

regmap: Merge up v6.4-rc6

2023-06-12T13:50:15+00:00

The fix for maple tree RCU locking on sync is a dependency for the
block sync code for the maple tree.

regmap: Add missing cache_only checks

2023-06-01T11:32:53+00:00

The current behaviour around cache_only is slightly inconsistent,
most paths will only check cache_only if cache_bypass is false,
and will return -EBUSY if a read attempts to go to the hardware
whilst cache_only is true. However, a couple of paths will not check
cache_only at all.  The most notable of these being regmap_raw_read
which will check cache_only in the case it processes the transaction
one register at a time, but not in the case it handles them as a
block. In the typical case a device has been put into cache_only
whilst powered down this can cause physical reads to happen whilst the
device is unavailable.

Add a check in regmap_raw_read and move the check in regmap_noinc_read,
adding a check for cache_bypass, such that all paths are covered and
consistent.

Signed-off-by: Charles Keepax 
Link: https://lore.kernel.org/r/20230601101036.1499612-2-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown

regmap: Account for register length when chunking

2023-05-18T01:53:42+00:00

Currently, when regmap_raw_write() splits the data, it uses the
max_raw_write value defined for the bus.  For any bus that includes
the target register address in the max_raw_write value, the chunked
transmission will always exceed the maximum transmission length.
To avoid this problem, subtract the length of the register and the
padding from the maximum transmission.

Signed-off-by: Jim Wylder

regmap: allow upshifting register addresses before performing operations

2023-04-07T16:28:19+00:00

Similar to the existing reg_downshift mechanism, that is used to
translate register addresses on busses that have a smaller address
stride, it's also possible to want to upshift register addresses.

Such a case was encountered when network PHYs and PCS that usually sit
on a MDIO bus (16-bits register with a stride of 1) are integrated
directly as memory-mapped devices. Here, the same register layout
defined in 802.3 is used, but the register now have a larger stride.

Introduce a mechanism to also allow upshifting register addresses.
Re-purpose reg_downshift into a more generic, signed reg_shift, whose
sign indicates the direction of the shift. To avoid confusion, also
introduce macros to explicitly indicate if we want to downshift or
upshift.

For bisectability, change any use of reg_downshift to use reg_shift.

Signed-off-by: Maxime Chevallier 
Tested-by: Colin Foster 
Link: https://lore.kernel.org/r/20230407152604.105467-1-maxime.chevallier@bootlin.com
Signed-off-by: Mark Brown