linux-stable.git/drivers/staging/comedi, branch v5.3

staging: comedi: dt3000: Fix rounding up of timer divisor

2019-08-12T14:46:12+00:00

`dt3k_ns_to_timer()` determines the prescaler and divisor to use to
produce a desired timing period.  It is influenced by a rounding mode
and can round the divisor up, down, or to the nearest value.  However,
the code for rounding up currently does the same as rounding down!  Fix
ir by using the `DIV_ROUND_UP()` macro to calculate the divisor when
rounding up.

Also, change the types of the `divider`, `base` and `prescale` variables
from `int` to `unsigned int` to avoid mixing signed and unsigned types
in the calculations.

Also fix a typo in a nearby comment: "improvment" => "improvement".

Signed-off-by: Ian Abbott 
Cc: stable 
Link: https://lore.kernel.org/r/20190812120814.21188-1-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman

staging: comedi: dt3000: Fix signed integer overflow 'divider * base'

2019-08-12T14:46:07+00:00

In `dt3k_ns_to_timer()` the following lines near the end of the function
result in a signed integer overflow:

	prescale = 15;
	base = timer_base * (1 << prescale);
	divider = 65535;
	*nanosec = divider * base;

(`divider`, `base` and `prescale` are type `int`, `timer_base` and
`*nanosec` are type `unsigned int`.  The value of `timer_base` will be
either 50 or 100.)

The main reason for the overflow is that the calculation for `base` is
completely wrong.  It should be:

	base = timer_base * (prescale + 1);

which matches an earlier instance of this calculation in the same
function.

Reported-by: David Binderman 
Cc: 
Signed-off-by: Ian Abbott 
Link: https://lore.kernel.org/r/20190812111517.26803-1-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman

staging: comedi: mite: Replace function mite_request_channel_in_range()

2019-07-03T16:28:28+00:00

Remove function mite_request_channel_in_range as all it does is call
__mite_request_channel.
Rename __mite_request_channel to mite_request_channel_in_range and
change its type from static to non-static to maintain compatibility with
call sites.
Change only remaining call site of __mite_request_channel to call
mite_request_channel_in_range_instead.
Issue found with Coccinelle.

Signed-off-by: Nishka Dasgupta 
Reviewed-by: Ian Abbott 
Link: https://lore.kernel.org/r/20190701070025.3838-3-nishkadg.linux@gmail.com
Signed-off-by: Greg Kroah-Hartman

staging: comedi: amplc_dio200: Remove function gat_sce()

2019-07-03T16:28:28+00:00

Remove function gat_sce as all it does is call clk_gat_sce.
Modify call sites of the former to call the latter directly.
Issue found with Coccinelle.

Signed-off-by: Nishka Dasgupta 
Reviewed-by: Ian Abbott 
Link: https://lore.kernel.org/r/20190701070025.3838-2-nishkadg.linux@gmail.com
Signed-off-by: Greg Kroah-Hartman

staging: comedi: amplc_dio200: Remove function clk_sce()

2019-07-03T16:28:28+00:00

Remove function clk_sce as all it does is call clk_gat_sce.
Modify call site of clk_sce to call clk_gat_sce instead.
Issue found with Coccinelle.

Signed-off-by: Nishka Dasgupta 
Reviewed-by: Ian Abbott 
Link: https://lore.kernel.org/r/20190701070025.3838-1-nishkadg.linux@gmail.com
Signed-off-by: Greg Kroah-Hartman

staging: comedi: dt282x: fix a null pointer deref on interrupt

2019-07-01T06:50:15+00:00

The interrupt handler `dt282x_interrupt()` causes a null pointer
dereference for those supported boards that have no analog output
support.  For these boards, `dev->write_subdev` will be `NULL` and
therefore the `s_ao` subdevice pointer variable will be `NULL`.  In that
case, the following call near the end of the interrupt handler results
in a null pointer dereference:

	comedi_handle_events(dev, s_ao);

Fix it by only calling the above function if `s_ao` is valid.

(There are other uses of `s_ao` by the interrupt handler that may or may
not be reached depending on values of hardware registers.  Trust that
they are reliable for now.)

Note:
commit 4f6f009b204f ("staging: comedi: dt282x: use comedi_handle_events()")
propagates an earlier error from
commit f21c74fa4cfe ("staging: comedi: dt282x: use cfc_handle_events()").

Fixes: 4f6f009b204f ("staging: comedi: dt282x: use comedi_handle_events()")
Cc:  # v3.19+
Signed-off-by: Ian Abbott 
Signed-off-by: Greg Kroah-Hartman

staging: comedi: amplc_pci230: fix null pointer deref on interrupt

2019-07-01T06:50:15+00:00

The interrupt handler `pci230_interrupt()` causes a null pointer
dereference for a PCI260 card.  There is no analog output subdevice for
a PCI260.  The `dev->write_subdev` subdevice pointer and therefore the
`s_ao` subdevice pointer variable will be `NULL` for a PCI260.  The
following call near the end of the interrupt handler results in the null
pointer dereference for a PCI260:

	comedi_handle_events(dev, s_ao);

Fix it by only calling the above function if `s_ao` is valid.

Note that the other uses of `s_ao` in the calls
`pci230_handle_ao_nofifo(dev, s_ao);` and `pci230_handle_ao_fifo(dev,
s_ao);` will never be reached for a PCI260, so they are safe.

Fixes: 39064f23284c ("staging: comedi: amplc_pci230: use comedi_handle_events()")
Cc:  # v3.19+
Signed-off-by: Ian Abbott 
Signed-off-by: Greg Kroah-Hartman

staging: comedi: use dma_mmap_coherent for DMA-able buffer mmap

2019-06-26T01:32:13+00:00

Comedi's acquisition buffer allocation code can allocate the buffer from
normal kernel memory or from DMA coherent memory depending on the
`dma_async_dir` value in the comedi subdevice.  (A value of `DMA_NONE`
causes the buffer to be allocated from normal kernel memory.  Other
values cause the buffer to be allocated from DMA coherent memory.)   The
buffer currently consists of a bunch of page-sized blocks that are
vmap'ed into a contiguous range of virtual addresses. The pages are also
mmap'able into user address space.  For DMA'able buffers, these
page-sized blocks are allocated by `dma_alloc_coherent()`.

For DMA-able buffers, the DMA API is currently abused in various ways,
the most serious abuse being the calling of `virt_to_page()` on the
blocks allocated by `dma_alloc_coherent()` and passing those pages to
`vmap()` (for mapping to the kernels vmalloc address space) and via
`page_to_pfn()` to `remap_pfn_range()` (for mmap'ing to user space).  it
also uses the `__GFP_COMP` flag when allocating the blocks, and marks
the allocated pages as reserved (which is unnecessary for DMA coherent
allocations).

The code can be changed to get rid of the vmap'ed address altogether if
necessary, since there are only a few places in the comedi code that use
the vmap'ed address directly and we also keep a list of the kernel
addresses for the individual pages prior to the vmap operation. This
would add some run-time overhead to buffer accesses.  The real killer is
the mmap operation.

For mmap, the address range specified in the VMA needs to be mmap'ed to
the individually allocated page-sized blocks.  That is not a problem
when the pages are allocated from normal kernel memory as the individual
pages can be remapped by `remap_pfn_range()`, but it is a problem when
the page-sized blocks are allocated by `dma_alloc_coherent()` because
the DMA API currently has no support for splitting a VMA across multiple
blocks of DMA coherent memory (or rather, no support for mapping part of
a VMA range to a single block of DMA coherent memory).

In order to comply with the DMA API and allow the buffer to be mmap'ed,
the buffer needs to be allocated as a single block by a single call to
`dma_alloc_coherent()`, freed by a single call to `dma_free_coherent()`,
and mmap'ed to user space by a single call to `dma_mmap_coherent()`.
This patch changes the buffer allocation, freeing, and mmap'ing code to
do that, with the unfortunate consequence that buffer allocation is more
likely to fail.  It also no longer uses the `__GFP_COMP` flag when
allocating DMA coherent memory, no longer marks the
allocated pages of DMA coherent memory as reserved, and no longer vmap's
the DMA coherent memory pages (since they are contiguous anyway).

Signed-off-by: Ian Abbott 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Greg Kroah-Hartman

staging: comedi: usbdux: remove redundant initialization of fx2delay

2019-06-18T06:59:40+00:00

Variable fx2delay is being initialized to a value that is never read
and is being re-assigned a few statements later. The initialization
is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King 
Reviewed-by: Ian Abbott 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'staging-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging

2019-05-07T20:31:29+00:00

Pull staging / IIO driver updates from Greg KH:
 "Here is the big staging and iio driver update for 5.2-rc1.

  Lots of tiny fixes all over the staging and IIO driver trees here,
  along with some new IIO drivers.

  The "counter" subsystem was added in here as well, as it is needed by
  the IIO drivers and subsystem.

  Also we ended up deleting two drivers, making this pull request remove
  a few hundred thousand lines of code, always a nice thing to see. Both
  of the drivers removed have been replaced with "real" drivers in their
  various subsystem directories, and they will be coming to you from
  those locations during this merge window.

  There are some core vt/selection changes in here, that was due to some
  cleanups needed for the speakup fixes. Those have all been acked by
  the various subsystem maintainers (i.e. me), so those are ok.

  We also added a few new drivers, for some odd hardware, giving new
  developers plenty to work on with basic coding style cleanups to come
  in the near future.

  Other than that, nothing unusual here.

  All of these have been in linux-next for a while with no reported
  issues, other than an odd gcc warning for one of the new drivers that
  should be fixed up soon"

[ I fixed up the warning myself  - Linus ]

* tag 'staging-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (663 commits)
  staging: kpc2000: kpc_spi: Fix build error for {read,write}q
  Staging: rtl8192e: Remove extra space before break statement
  Staging: rtl8192u: ieee80211: Fix if-else indentation warning
  Staging: rtl8192u: ieee80211: Fix indentation errors by removing extra spaces
  staging: most: cdev: fix chrdev_region leak in mod_exit
  staging: wlan-ng: Fix improper SPDX comment style
  staging: rtl8192u: ieee80211: Resolve ERROR reported by checkpatch
  staging: vc04_services: bcm2835-camera: Compress two lines into one line
  staging: rtl8723bs: core: Use !x in place of NULL comparison.
  staging: rtl8723bs: core: Prefer using the BIT Macro.
  staging: fieldbus: anybus-s: fix wait_for_completion_timeout return handling
  staging: kpc2000: fix up build problems with readq()
  staging: rtlwifi: move remaining phydm .h files
  staging: rtlwifi: strip down phydm .h files
  staging: rtlwifi: delete the staging driver
  staging: fieldbus: anybus-s: rename bus id field to avoid confusion
  staging: fieldbus: anybus-s: keep device bus id in bus endianness
  Staging: sm750fb: Change *array into *const array
  staging: rtl8192u: ieee80211: Fix spelling mistake
  staging: rtl8192u: ieee80211: Replace bit shifting with BIT macro
  ...