linux-toradex.git/drivers/spi/spi.c, branch v4.1.5

spi: fix race freeing dummy_tx/rx before it is unmapped

2015-07-21T17:10:04+00:00

commit 8e76ef88f607174082023f50b87fe12dcdbe5db5 upstream.

Fix a race (with some kernel configurations) where a queued
master->pump_messages runs and frees dummy_tx/rx before
spi_unmap_msg is running (or is finished).

This results in the following messages:
  BUG: Bad page state in process
  page:db7ba030 count:0 mapcount:0 mapping:  (null) index:0x0
  flags: 0x200(arch_1)
  page dumped because: PAGE_FLAGS_CHECK_AT_PREP flag set
  ...

Reported-by: Noralf Trønnes 
Suggested-by: Noralf Trønnes 
Tested-by: Noralf Trønnes 
Signed-off-by: Martin Sperl 
Signed-off-by: Mark Brown 
Signed-off-by: Greg Kroah-Hartman

spi: check tx_buf and rx_buf in spi_unmap_msg

2015-04-16T17:58:05+00:00

Some spi device drivers use the same tx_buf and rx_buf repeatly for better
performance such as driver/input/touchsreen/ads7846.c, but spi core grab tx_buf
/rx_buf of transfer and set them as dummy_tx/dummy_rx once they are NULL. Thus,
in the second time the tx_buf/rx_buf will be replaced by dummy_tx/dummy_rx and
the data which produced by the last tx or rx may be wrongly sent to the device
or handled by the upper level protocol. This patch just keep the orignal value
of tx_buf/rx_buf if they are NULL after this transfer processed.

Signed-off-by: Robin Gong 
Signed-off-by: Mark Brown

Merge remote-tracking branches 'spi/topic/omap-100k', 'spi/topic/omap-uwire', 'spi/topic/pl022', 'spi/topic/pm' and 'spi/topic/pxa2xx' into spi-next

2015-04-11T22:09:18+00:00

Merge remote-tracking branches 'spi/topic/blackfin', 'spi/topic/cadence', 'spi/topic/dw' and 'spi/topic/err' into spi-next

2015-04-11T22:09:09+00:00

Merge remote-tracking branches 'spi/topic/atmel', 'spi/topic/bcm2385', 'spi/topic/bcm2835', 'spi/topic/bcm53xx' and 'spi/topic/bitbang' into spi-next

2015-04-11T22:09:03+00:00

Merge remote-tracking branch 'spi/topic/core' into spi-next

2015-04-11T22:09:00+00:00

spi: Make master->handle_err() callback optional to avoid crashes

2015-04-07T18:41:32+00:00

If a driver doesn't implement the master->handle_err() callback and an
SPI transfer fails, the kernel will crash with a NULL pointer
dereference:

    Unable to handle kernel NULL pointer dereference at virtual address 00000000
    pgd = c0003000
    [00000000] *pgd=80000040004003, *pmd=00000000
    Internal error: Oops: 80000206 [#1] SMP ARM
    Modules linked in:
    CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.0.0-rc7-koelsch-05861-g1fc9fdd4add4f783 #1046
    Hardware name: Generic R8A7791 (Flattened Device Tree)
    task: eec359c0 ti: eec54000 task.ti: eec54000
    PC is at 0x0
    LR is at spi_transfer_one_message+0x1cc/0x1f0

Make the master->handle_err() callback optional to avoid the crash.

Also fix a spelling mistake in the callback documentation while we're at
it.

Fixes: b716c4ffc6a2b0bf ("spi: introduce master->handle_err() callback")
Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Mark Brown

spi: of: do explicitly request modules for of-registered devices

2015-03-25T21:34:52+00:00

Trying to register an SPI device asynchronously (via async_schedule() call)
results in an ugly complaint from request_module() warning about potential
deadlock (because request_module tries to wait for async works to
complete, the caller is also an async work in this case).

While we could try to switch to using request_module_nowait(), other buses,
as well as SPI itself when not using device tree, do not try to load
modules explicitly, but rather rely on the standard infrastructure (such as
udev) to execute module loading. There is no reason why SPI OF-described
devices should be treated differently.

Signed-off-by: Dmitry Torokhov 
Signed-off-by: Mark Brown

spi: trigger trace event for message-done before mesg->complete

2015-03-18T11:34:10+00:00

With spidev the mesg->complete callback points to spidev_complete.
Calling this unblocks spidev_sync and so spidev_sync_write finishes. As
the struct spi_message just read is a local variable in
spidev_sync_write and recording the trace event accesses this message
the recording is better done first. The same can happen for
spidev_sync_read.

This fixes an oops observed on a 3.14-rt system with spidev activity
after

	echo 1 > /sys/kernel/debug/tracing/events/spi/enable

.

Signed-off-by: Uwe Kleine-König 
Signed-off-by: Mark Brown 
Cc: stable@vger.kernel.org

spi: Ensure that CS line is in non-active state after spi_setup()

2015-03-16T14:06:48+00:00

Some devices samples state of the chip select signal during power up
and act differently based on this state, so SPI core should ensure
that CS line is driven in non-active state after spi_setup().

Signed-off-by: Ivan T. Ivanov 
Signed-off-by: Mark Brown