We currently silently omit creating the debugfs entries when regmap
locking is disabled. Users may not be aware of the reason for which
regmap files don't show up in debugfs. Add a dev_dbg() message
explaining that.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: NMark Brown <broonie@kernel.org>

The recently added support for disabling the regmap internal locking left
debugfs enabled for devices with the locking disabled. This is a problem
since debugfs allows userspace to do things like initiate reads from the
hardware which will use the scratch buffers protected by the regmap locking
so could cause data corruption.

For safety address this by just disabling debugfs for these devices. That
is overly conservative since some of the debugfs files just read internal
data structures but it's much simpler to implmement and less likely to
lead to problems with tooling that works with debugfs.
Reported-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NMark Brown <broonie@kernel.org>

Add support for dumping write only device registers in debugfs. This is
useful for audio codecs that have write only registers (like WM8731).
The logic that decides if a value can be printed is moved to
regmap_printable() function to allow for easier future updates.
Signed-off-by: NCristian Birsan <cristian.birsan@microchip.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Unlike the registers file we don't have any substantial performance
concerns rendering the entire file (it involves no device accesses) so
just use seq_printf() to simplify the code.
Signed-off-by: NMark Brown <broonie@kernel.org>

By printing the newline character to entry, we can avoid accounting
for it manually in several places.
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: NMark Brown <broonie@kernel.org>

Since we know the length of entry and that there's room enough in the
output buffer, using memcpy instead of snprintf is simpler and
cheaper.
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: NMark Brown <broonie@kernel.org>

Calling strlen() no less than three times on entry is silly. Since
we're formatting into a buffer with plenty of room, there's no chance
of truncation, so snprintf() has actually returned the value we want,
meaning we don't even have to call strlen once.
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: NMark Brown <broonie@kernel.org>

Now we no longer use the scratch buffer for register length calculation
there is no need for callers to supply one.
Signed-off-by: NMark Brown <broonie@kernel.org>

The in kernel snprintf() will conveniently return the actual length of
the printed string even if not given an output beffer at all so just do
that rather than relying on the user to pass in a suitable buffer,
ensuring that we don't need to worry if the buffer was truncated due to
the size of the buffer passed in.
Reported-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: NMark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

If a read is attempted which is smaller than the line length then we may
underflow the subtraction we're doing with the unsigned size_t type so
move some of the calculation to be additions on the right hand side
instead in order to avoid this.
Reported-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: NMark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

IS_ENABLED should only be used for CONFIG_* symbols.

I have done a small test:
  #define REGMAP_ALLOW_WRITE_DEBUGFS
  IS_ENABLED(REGMAP_ALLOW_WRITE_DEBUGFS) returns 0.

  #define REGMAP_ALLOW_WRITE_DEBUGFS 0
  IS_ENABLED(REGMAP_ALLOW_WRITE_DEBUGFS) returns 0.

  #define REGMAP_ALLOW_WRITE_DEBUGFS 1
  IS_ENABLED(REGMAP_ALLOW_WRITE_DEBUGFS) returns 1.

  #define REGMAP_ALLOW_WRITE_DEBUGFS 2
  IS_ENABLED(REGMAP_ALLOW_WRITE_DEBUGFS) returns 0.

So fix the misuse of IS_ENABLED(REGMAP_ALLOW_WRITE_DEBUGFS) and switch to
use #if defined(REGMAP_ALLOW_WRITE_DEBUGFS) instead.
Signed-off-by: NAxel Lin <axel.lin@ingics.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Allow the user to write the cache_only and cache_bypass settings.
This can be useful for debugging.

Since this can lead to the hardware getting out-of-sync with the
cache, at least for the period that the cache state is forced, the
kernel is tainted and the action is recorded in the kernel log.

When disabling cache_only through debugfs a cache sync will be performed.
Signed-off-by: NRichard Fitzgerald <rf@opensource.wolfsonmicro.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

The macro "REGMAP_ALLOW_WRITE_DEBUGFS" can be used to enable write
support on the registers file in the debugfs. The mode of the file is
fixed to 0400 so it is not possible to write the file ever.

This patch fixes the mode by setting it to the correct value depending
on the macro.
Signed-off-by: NMarkus Pargmann <mpa@pengutronix.de>
Signed-off-by: NMark Brown <broonie@kernel.org>

If 'map->dev' is NULL and there will lead dev_name() to be NULL pointer
dereference. So before dev_name(), we need to have check of the map->dev
pionter.

We also should make sure that the 'name' pointer shouldn't be NULL for
debugfs_create_dir(). So here using one default "dummy" debugfs name when
the 'name' pointer and 'map->dev' are both NULL.
Signed-off-by: NXiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: NMark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

The macro "REGMAP_ALLOW_WRITE_DEBUGFS" can be used to enable write
support on the registers file in the debugfs. The mode of the file is
fixed to 0400 so it is not possible to write the file ever.

This patch fixes the mode by setting it to the correct value depending
on the macro.
Signed-off-by: NMarkus Pargmann <mpa@pengutronix.de>
Signed-off-by: NMark Brown <broonie@kernel.org>

Commit 6cfec04b ("regmap: Separate regmap dev initialization") moved the
regmap debugfs initialization after regcache initialization. This means
that the regmap debugfs directory is not created yet when the cache
initialization runs and so any debugfs files registered by the regcache are
created in the debugfs root directory rather than the debugfs directory of
the regmap instance. Fix this by adding a separate callback for the
regcache debugfs initialization which will be called after the parent
debugfs entry has been created.

Fixes: 6cfec04b (regmap: Separate regmap dev initialization)
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NMark Brown <broonie@linaro.org>
Cc: stable@vger.kernel.org

When a map covers a single register, max_register is equal
to 0, so the "registers" & "access" files were not created.
Now they will be, as register 0 must be readable for such
map to make sense.
Signed-off-by: NPawel Moll <pawel.moll@arm.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

If called early enough, regmap_debugfs_init causes a crash, if the
fs subsystem does not have its mount cache created yet. Even if this
would work, the root node for the regmap debugfs is still missing,
thus postpone the regmap_debugfs_init in this case until the root
node is created. A special regmap_debugfs_early list is created for
this purpose which is parsed later in the boot.
Signed-off-by: NTero Kristo <t-kristo@ti.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

The regmap_debugfs_get_dump_start() function maps from a file offset to the
register that can be found at that position in the file. This is done using a
look-up table. Commit d6814a7d ("regmap: debugfs: Suppress cache for partial
register files") added a check to bypass the look-up table for partial register
files, since the offsets in that table are only correct for the full register
file. The check incorrectly uses the file offset instead of the register base
address and returns it. This will cause the file offset to be interpreted as a
register address which will result in a incorrect output from the registers file
for all reads except at position 0.

The issue can easily be reproduced by doing small reads the registers file, e.g.
`dd if=registers bs=10 count=5`.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NMark Brown <broonie@linaro.org>
Cc: stable@vger.kernel.org

The usage of strict_strto*() is not preferred, because
strict_strto*() is obsolete. Thus, kstrto*() should be
used.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The cache is based on the full register map so confuses things if used
for a partial map.
Reported-by: NBard Liao <bardliao@realtek.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

regmap_debugfs_get_dump_start should return the offset of the register
it should start reading from, However in the current code at one point
the code does not return correct register offset.

With this patch all the returns from this function takes reg_stride in
to consideration to return correct offset.
Signed-off-by: NSrinivas Kandagatla <srinivas.kandagatla@st.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

A register write to hardware is reasonably unlikely to cause locking
dependency issues, the reason we're tainting is that unexpected changes
in the hardware configuration may confuse drivers.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

Signed-off-by: NDimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

This file lists the register ranges in the register map.  The condition
to split the range is based on whether the block is readable or not.

Ensure that we lock the `debugfs_off_cache' list whenever we access
and modify the list.  There is a possible race otherwise between the
read() operations of the `registers' file and the `range' file.
Signed-off-by: NDimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

We don't need to use any of the file position information
to calculate the base and max register of each block.  Just
use the counter directly.

Set `i = base' at the top to avoid GCC flow analysis bugs.  The
value of `i' can never be undefined or 0 in the if (c) { ... }.
Signed-off-by: NDimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

In preparation to support the regmap debugfs ranges functionality
factor this code out to a separate function.  We'll need to ensure
that the value has been correctly calculated from two separate places
in the code.
Signed-off-by: NDimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

Optimize this so that we can better guess where to start scanning
from.  We know the length of the register field format, therefore
given the file pointer position align to the nearest register
field and scan from there onwards.  We round down in this calculation
and we let the rest of the code figure out where to start scanning
from.
Signed-off-by: NDimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

We are keeping track of the maximum register as well, this will make
things easier for us in sharing this code with the code implementing
the register ranges functionality.  It also simplifies a bit the
calculations when looking for the relevant block:offset from within
the cache.
Signed-off-by: NDimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

At the moment, if the length of the register field format is
N bytes, we can only get anything meaningful back to userspace
by providing a buffer that is N + 2 bytes large.  Fix this
so we that we only need to provide a buffer of N bytes.
Signed-off-by: NDimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

Gcc warns about the case where regmap_read_debugfs tries to walk an
empty map->debugfs_off_cache list, which would results in uninitialized
variable getting returned, if we hadn't checked the same condition
just before that.

After an originally suggested inferior patch from Arnd Bergmann,
this is the solution that Russell King came up with, sidestepping
the problem by merging the error case for an empty list with the
normal path.

Without this patch, building mxs_defconfig results in:

drivers/base/regmap/regmap-debugfs.c: In function 'regmap_read_debugfs':
drivers/base/regmap/regmap-debugfs.c:147:9: : warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]
Reported-by: NVincent Stehle <v-stehle@ti.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

Fix up all callers as they were before, with make one change: an
unsigned module taints the kernel, but doesn't turn off lockdep.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

We don't want to bomb out early if we failed to get the cache any more,
just soldier on instead and we won't get confused and always return the
first block.

Reported-by: Philipp Zabel <p.zabel@pengutronix.de
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

This should never happen in the real world.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

Rather than trying to soldier on with a partially allocated cache just
throw the cache away and pretend we don't have one in case we can get a
full cache next time around.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

Check for the block we were asked to start from, not the position we're
in.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

Return the start of the last block we tried to read rather than a position,
and also make sure we update the byte position while we're at it.  Without
this reads that go into nonexistant areas get confused.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

Avoid doing a linear scan of the entire register map for each read() of
the debugfs register dump by recording the offsets where valid registers
exist when we first read the registers file. This assumes the set of
valid registers never changes, if this is not the case invalidation of
the cache will be required.

This could be further improved for large blocks of contiguous registers
by calculating the register we will read from within the block - currently
we do a linear scan of the block. An rbtree may also be worthwhile.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

In preparation for doing things a bit more quickly than a linear scan
factor out the initial seek from the debugfs register dump.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>