Implement the function which wait until a dma channel is stopped to have
a synchronization point.
This also protects the pxad_remove() from races, such as spurious
interrupts while removing the driver, because :
- as long as there is one dma channel requested, ie. dma_chan_get() but
no dma_chan_put(), the try_module_get() of dma_chan_get() prevents
the remove() routine from running
- when the last channel is released, ie. the last dma_chan_put() is
called, if there is a running DMA, pxad_synchronize() is called
- pxad_synchronize() waits for the channel to stop, which in turn
ensures on pxa architecture that the interrupt cannot be fired anymore
Reported-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
debugfs file operations owner is set by core, so remove
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
In the current state, upon bus error the driver will spin endlessly,
relaunching the last tx, which will fail again and again :
- a bus error happens
- pxad_chan_handler() is called
- as PXA_DCSR_STOPSTATE is true, the last non-terminated transaction is
lauched, which is the one triggering the bus error, as it didn't
terminate
- moreover, the STOP interrupt fires a new, as the STOPIRQEN is still
active
Break this logic by stopping the automatic relaunch of a dma channel
upon a bus error, even if there are still pending issued requests on it.
As dma_cookie_status() seems unable to return DMA_ERROR in its current
form, ie. there seems no way to mark a DMA_ERROR on a per-async-tx
basis, it is chosen in this patch to remember on the channel which
transaction failed, and report it in pxad_tx_status().
It's a bit misleading because if T1, T2, T3 and T4 were queued, and T1
was completed while T2 causes a bus error, the status of T3 and T4 will
be reported as DMA_IN_PROGRESS, while the channel is actually stopped.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Newly added support for additional SoCs:
- Axis Artpec-6 SoC family
- Allwinner A83T SoC
- Mediatek MT7623
- NXP i.MX6QP SoC
- ST Microelectronics stm32f469 microcontroller
New features:
- SMP support for Mediatek mt2701
- Big-endian support for NXP i.MX
- DaVinci now uses the new DMA engine dma_slave_map
- OMAP now uses the new DMA engine dma_slave_map
- earlyprintk support for palmchip uart on mach-tango
- delay timer support for orion
Other:
- Exynos PMU driver moved out to drivers/soc/
- Various smaller updates for Renesas, Xilinx, PXA, AT91, OMAP, uniphier
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Merge tag 'armsoc-soc' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC platform updates from Arnd Bergmann:
"Newly added support for additional SoCs:
- Axis Artpec-6 SoC family
- Allwinner A83T SoC
- Mediatek MT7623
- NXP i.MX6QP SoC
- ST Microelectronics stm32f469 microcontroller
New features:
- SMP support for Mediatek mt2701
- Big-endian support for NXP i.MX
- DaVinci now uses the new DMA engine dma_slave_map
- OMAP now uses the new DMA engine dma_slave_map
- earlyprintk support for palmchip uart on mach-tango
- delay timer support for orion
Other:
- Exynos PMU driver moved out to drivers/soc/
- Various smaller updates for Renesas, Xilinx, PXA, AT91, OMAP,
uniphier"
* tag 'armsoc-soc' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (83 commits)
ARM: uniphier: rework SMP code to support new System Bus binding
ARM: uniphier: add missing of_node_put()
ARM: at91: avoid defining CONFIG_* symbols in source code
ARM: DRA7: hwmod: Add data for eDMA tpcc, tptc0, tptc1
ARM: imx: Make reset_control_ops const
ARM: imx: Do L2 errata only if the L2 cache isn't enabled
ARM: imx: select ARM_CPU_SUSPEND only for imx6
dmaengine: pxa_dma: fix the maximum requestor line
ARM: alpine: select the Alpine MSI controller driver
ARM: pxa: add the number of DMA requestor lines
dmaengine: mmp-pdma: add number of requestors
dma: mmp_pdma: Add the #dma-requests DT property documentation
ARM: OMAP2+: Add rtc hwmod configuration for ti81xx
ARM: s3c24xx: Avoid warning for inb/outb
ARM: zynq: Move early printk virtual address to vmalloc area
ARM: DRA7: hwmod: Add custom reset handler for PCIeSS
ARM: SAMSUNG: Remove unused register offset definition
ARM: EXYNOS: Cleanup header files inclusion
drivers: soc: samsung: Enable COMPILE_TEST
MAINTAINERS: Add maintainers entry for drivers/soc/samsung
...
While testing audio with pxa2xx-ac97, underrun were happening while the
user application was correctly feeding the music. Debug proved that the
cyclic transfer is not cyclic, ie. the last descriptor did not loop on
the first.
Another issue is that the descriptor length was always set to 8192,
because of an trivial operator issue.
This was tested on a pxa27x platform.
Fixes: a57e16cf03 ("dmaengine: pxa: add pxa dmaengine driver")
Reported-by: Vasily Khoruzhick <anarsoul@gmail.com>
Tested-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
The current number of requestor lines is limited to 31. This was an
error of a previous commit, as this number is platform dependent, and is
actually :
- for pxa25x: 40 requestor lines
- for pxa27x: 75 requestor lines
- for pxa3xx: 100 requestor lines
The previous testing did not reveal the faulty constant as on pxa[23]xx
platforms, only camera, MSL and USB are above requestor 32, and in these
only the camera has a driver using dma.
Fixes: e87ffbdf06 ("dmaengine: pxa_dma: fix the no-requestor case")
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Acked-by: Vinod Koul <vinod.koul@intel.com>
As this driver provides a mechanism to reuse transfers, declare it in
its probe function.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
A very tiny temporal window exists in the residue calculation where :
- upon entering residue calculation, the transfer is ongoing
- when reading the current transfer pointer, it just changed to
the "finisher/linker" descriptor
In this case, the residue returned is the whole transfer length instead
of 0. Fix it.
This appears almost in one extreme case, where the driver is used
by older clients which inquire for residue in interrupt context, such
as the smsc91x ethernet driver, in a tight loop :
interrupt_handler()
dmaengine_submit()
do {
dmaengine_tx_status()
} while (residue > 0 || status != DMA_ERROR)
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
A very small number of devices don't use the flow control offered by
requestor lines. In these specific cases, the pxa dma driver should be
aware of that and not try to use a requestor line.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Since the commit to have an allocated list of virtual descriptors was
reverted, the pxa_dma driver is broken, as it assumes the descriptor is
placed on the allocated list upon allocation.
Fix the issue in pxa_dma by making an allocated virtual descriptor a
singleton.
Fixes: 8c8fe97b2b ("Revert "dmaengine: virt-dma: don't always free descriptor upon completion"")
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This fixes the following error:
drivers/dma/pxa_dma.c: In function ‘dbg_show_requester_chan’:
drivers/dma/pxa_dma.c:192:2: error: void value not ignored as it ought to be
pos += seq_printf(s, "DMA channel %d requester :\n", phy->idx);
^
drivers/dma/pxa_dma.c:197:8: error: void value not ignored as it ought to be
!!(drcmr & DRCMR_MAPVLD));
^
scripts/Makefile.build:258: recipe for target 'drivers/dma/pxa_dma.o' failed
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Don't use the direction passed in the configuration, and rely on each
transfer's direction to prepare the transfers. This will enable
future removal of direction parameter from dma_slave_config.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
In order to achieve smooth transition of pxa drivers from old legacy dma
handling to new dmaengine, introduce a function to "hide" dma physical
channels from dmaengine.
This is temporary situation where pxa dma will be handled in 2 places :
- arch/arm/plat-pxa/dma.c
- drivers/dma/pxa_dma.c
The resources, ie. dma channels, will be controlled by pxa_dma. The
legacy code will request or release a channel with
pxad_toggle_reserved_channel().
This is not very pretty, but it ensures both legacy and dmaengine
consumers can live in the same kernel until the conversion is done.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Reuse the debugging features which were available in pxa architecture.
This is a copy of the code from arch/arm/plat-pxa/dma, which is doomed
to disappear once the conversion is completed towards dmaengine.
This is a transfer of the commit "[ARM] pxa/dma: add debugfs
entries" (d294948c2c).
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This is a new driver for pxa SoCs, which is also compatible with the former
mmp_pdma.
The rationale behind a new driver (as opposed to incremental patching) was :
- the new driver relies on virt-dma, which obsoletes all the internal
structures of mmp_pdma (sw_desc, hw_desc, ...), and by consequence all the
functions
- mmp_pdma allocates dma coherent descriptors containing not only hardware
descriptors but linked list information
The new driver only puts the dma hardware descriptors (ie. 4 u32) into the
dma pool allocated memory. This changes completely the way descriptors are
handled
- the architecture behind the interrupt/tasklet management was rewritten to be
more conforming to virt-dma
- the buffers alignment is handled differently
The former driver assumed that the DMA channel stopped between each
descriptor. The new one chains descriptors to let the channel running. This
is a necessary guarantee for real-time high bandwidth usecases such as video
capture on "old" architectures such as pxa.
- hot chaining / cold chaining / no chaining
Whenever possible, submitting a descriptor "hot chains" it to a running
channel. There is still no guarantee that the descriptor will be issued, as
the channel might be stopped just before the descriptor is submitted. Yet
this allows to submit several video buffers, and resubmit a buffer while
another is under handling.
As before, dma_async_issue_pending() is the only guarantee to have all the
buffers issued.
When an alignment issue is detected (ie. one address in a descriptor is not
a multiple of 8), if the already running channel is in "aligned mode", the
channel will stop, and restarted in "misaligned mode" to finished the issued
list.
- descriptors reusing
A submitted, issued and completed descriptor can be reused, ie resubmitted if
it was prepared with the proper flag (DMA_PREP_ACK). Only a channel
resources release will in this case release that buffer.
This allows a rolling ring of buffers to be reused, where there are several
thousands of hardware descriptors used (video buffer for example).
Additionally, a set of more casual features is introduced :
- debugging traces
- lockless way to know if a descriptor is terminated or not
The driver was tested on zylonite board (pxa3xx) and mioa701 (pxa27x),
with dmatest, pxa_camera and pxamci.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
