linux-toradex.git/drivers/dma/dmaengine.c, branch v5.9-rc5

dmaengine: Introduce DMA-device device_caps callback

2020-07-27T09:00:55+00:00

There are DMA devices (like ours version of Synopsys DW DMAC) which have
DMA capabilities non-uniformly redistributed between the device channels.
In order to provide a way of exposing the channel-specific parameters to
the DMA engine consumers, we introduce a new DMA-device callback. In case
if provided it gets called from the dma_get_slave_caps() method and is
able to override the generic DMA-device capabilities.

Signed-off-by: Serge Semin 
Reviewed-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20200723005848.31907-6-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Vinod Koul

dmaengine: Introduce max SG burst capability

2020-07-27T09:00:54+00:00

Some devices may lack the support of the hardware accelerated SG list
entries automatic walking through and execution. In this case a burden of
the SG list traversal and DMA engine re-initialization lies on the
DMA engine driver (normally implemented by using a DMA transfer completion
IRQ to recharge the DMA device with a next SG list entry). But such
solution may not be suitable for some DMA consumers. In particular SPI
devices need both Tx and Rx DMA channels work synchronously in order
to avoid the Rx FIFO overflow. In case if Rx DMA channel is paused for
some time while the Tx DMA channel works implicitly pulling data into the
Rx FIFO, the later will be eventually overflown, which will cause the data
loss. So if SG list entries aren't automatically fetched by the DMA
engine, but are one-by-one manually selected for execution in the
ISRs/deferred work/etc., such problem will eventually happen due to the
non-deterministic latencies of the service execution.

In order to let the DMA consumer know about the DMA device capabilities
regarding the hardware accelerated SG list traversal we introduce the
max_sg_burst capability. It is supposed to be initialized by the DMA engine
driver with 0 if there is no limitation of the number of SG entries
atomically executed and with non-zero value if there is such constraints,
so the upper limit is determined by the number set to the property.

Suggested-by: Andy Shevchenko 
Signed-off-by: Serge Semin 
Reviewed-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20200723005848.31907-5-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Vinod Koul

dmaengine: Introduce min burst length capability

2020-07-27T09:00:54+00:00

Some hardware aside from default 0/1 may have greater minimum burst
transactions length constraints. Here we introduce the DMA device
and slave capability, which if required can be initialized by the DMA
engine driver with the device-specific value.

Signed-off-by: Serge Semin 
Reviewed-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20200723005848.31907-4-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Vinod Koul

Merge tag 'dmaengine-5.8-rc1' of git://git.infradead.org/users/vkoul/slave-dma

2020-06-10T18:03:04+00:00

Pull dmaengine updates from Vinod Koul:
 "A fairly small dmaengine update which includes mostly driver updates
  (dmatest, dw-edma, ioat, mmp-tdma and k3-udma) along with Renesas
  binding update to json-schema"

* tag 'dmaengine-5.8-rc1' of git://git.infradead.org/users/vkoul/slave-dma: (39 commits)
  dmaengine: imx-sdma: initialize all script addresses
  dmaengine: ti: k3-udma: Use proper return code in alloc_chan_resources
  dmaengine: ti: k3-udma: Remove udma_chan.in_ring_cnt
  dmaengine: ti: k3-udma: Add missing dma_sync call for rx flush descriptor
  dmaengine: at_xdmac: Replace zero-length array with flexible-array
  dmaengine: at_hdmac: Replace zero-length array with flexible-array
  dmaengine: qcom: bam_dma: Replace zero-length array with flexible-array
  dmaengine: ti: k3-udma: Use PTR_ERR_OR_ZERO() to simplify code
  dmaengine: moxart-dma: Drop pointless static qualifier in moxart_probe()
  dmaengine: sf-pdma: Simplify the error handling path in 'sf_pdma_probe()'
  dmaengine: qcom_hidma: use true,false for bool variable
  dmaengine: dw-edma: support local dma device transfer semantics
  dmaengine: Fix doc strings to satisfy validation script
  dmaengine: Include dmaengine.h into dmaengine.c
  dmaengine: dmatest: Describe members of struct dmatest_info
  dmaengine: dmatest: Describe members of struct dmatest_params
  dmaengine: dmatest: Allow negative timeout value to specify infinite wait
  Revert "dmaengine: dmatest: timeout value of -1 should specify infinite wait"
  dmaengine: stm32-dma: direct mode support through device tree
  dt-bindings: dma: add direct mode support through device tree in stm32-dma
  ...

dmaengine: Fix doc strings to satisfy validation script

2020-05-04T05:28:03+00:00

The validation kernel doc script complains about undescribed
function parameters

.../dmaengine.c:155: warning: Function parameter or member 'dev' not descr ibed in 'dev_to_dma_chan'
.../dmaengine.c:251: warning: cannot understand function prototype: 'dma_cap_mask_t dma_cap_mask_all; '
.../dmaengine.c:257: warning: cannot understand function prototype: 'struct dma_chan_tbl_ent '
.../dmaengine.c:264: warning: cannot understand function prototype: 'struct dma_chan_tbl_ent __percpu *channel_table[DMA_TX_TYPE_END]; '
.../dmaengine.c:304: warning: Function parameter or member 'chan' not described in 'dma_chan_is_local'
.../dmaengine.c:304: warning: Function parameter or member 'cpu' not described in 'dma_chan_is_local'
.../dmaengine.c:414: warning: Function parameter or member 'chan' not described in 'balance_ref_count'
.../dmaengine.c:447: warning: Function parameter or member 'chan' not described in 'dma_chan_get'
.../dmaengine.c:494: warning: Function parameter or member 'chan' not described in 'dma_chan_put'

Add descriptions to the function parameters and in some cases update
existing text as well.

Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20200429122151.50989-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Vinod Koul

dmaengine: Include dmaengine.h into dmaengine.c

2020-05-04T05:28:03+00:00

Compiler is not happy about non-static functions due to missed inclusion

.../dmaengine.c:682:18: warning: no previous prototype for ‘dma_get_slave_channel’ [-Wmissing-prototypes]
  682 | struct dma_chan *dma_get_slave_channel(struct dma_chan *chan)
      |                  ^~~~~~~~~~~~~~~~~~~~~
.../dmaengine.c:713:18: warning: no previous prototype for ‘dma_get_any_slave_channel’ [-Wmissing-prototypes]
  713 | struct dma_chan *dma_get_any_slave_channel(struct dma_device *device)
      |                  ^~~~~~~~~~~~~~~~~~~~~~~~~

Include missed header to satisfy compiler.

Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20200429122151.50989-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Vinod Koul

dmaengine: fix channel index enumeration

2020-04-27T15:56:23+00:00

When the channel register code was changed to allow hotplug operations,
dynamic indexing wasn't taken into account. When channels are randomly
plugged and unplugged out of order, the serial indexing breaks. Convert
channel indexing to using IDA tracking in order to allow dynamic
assignment. The previous code does not cause any regression bug for
existing channel allocation besides idxd driver since the hotplug usage
case is only used by idxd at this point.

With this change, the chan->idr_ref is also not needed any longer. We can
have a device with no channels registered due to hot plug. The channel
device release code no longer should attempt to free the dma device id on
the last channel release.

Fixes: e81274cd6b52 ("dmaengine: add support to dynamic register/unregister of channels")

Reported-by: Yixin Zhang 
Signed-off-by: Dave Jiang 
Tested-by: Yixin Zhang 
Link: https://lore.kernel.org/r/158679961260.7674.8485924270472851852.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul

Merge tag 'dmaengine-5.7-rc1' of git://git.infradead.org/users/vkoul/slave-dma

2020-04-02T23:04:42+00:00

Pull dmaengine updates from Vinod Koul:
 "Core:
   - Some code cleanup and optimization in core by Andy

   - Debugfs support for displaying dmaengine channels by Peter

  Drivers:
   - New driver for uniphier-xdmac controller

   - Updates to stm32 dma, mdma and dmamux drivers and PM support

   - More updates to idxd drivers

   - Bunch of changes in tegra-apb driver and cleaning up of pm
     functions

   - Bunch of spelling fixes and Replace zero-length array patches

   - Shutdown hook for fsl-dpaa2-qdma driver

   - Support for interleaved transfers for ti-edma and virtualization
     support for k3-dma driver

   - Support for reset and updates in xilinx_dma driver

   - Improvements and locking updates in at_hdma driver"

* tag 'dmaengine-5.7-rc1' of git://git.infradead.org/users/vkoul/slave-dma: (89 commits)
  dt-bindings: dma: renesas,usb-dmac: add r8a77961 support
  dmaengine: uniphier-xdmac: Remove redandant error log for platform_get_irq
  dmaengine: tegra-apb: Improve DMA synchronization
  dmaengine: tegra-apb: Don't save/restore IRQ flags in interrupt handler
  dmaengine: tegra-apb: mark PM functions as __maybe_unused
  dmaengine: fix spelling mistake "exceds" -> "exceeds"
  dmaengine: sprd: Set request pending flag when DMA controller is active
  dmaengine: ppc4xx: Use scnprintf() for avoiding potential buffer overflow
  dmaengine: idxd: remove global token limit check
  dmaengine: idxd: reflect shadow copy of traffic class programming
  dmaengine: idxd: Merge definition of dsa_batch_desc into dsa_hw_desc
  dmaengine: Create debug directories for DMA devices
  dmaengine: ti: k3-udma: Implement custom dbg_summary_show for debugfs
  dmaengine: Add basic debugfs support
  dmaengine: fsl-dpaa2-qdma: remove set but not used variable 'dpaa2_qdma'
  dmaengine: ti: edma: fix null dereference because of a typo in pointer name
  dmaengine: fsl-dpaa2-qdma: Adding shutdown hook
  dmaengine: uniphier-xdmac: Add UniPhier external DMA controller driver
  dt-bindings: dmaengine: Add UniPhier external DMA controller bindings
  dmaengine: ti: k3-udma: Implement support for atype (for virtualization)
  ...

dmaengine: Create debug directories for DMA devices

2020-03-11T09:26:14+00:00

Create a placeholder directory for each registered DMA device.

DMA drivers can use the dmaengine_get_debugfs_root() call to get their
debugfs root and can populate with custom files to aim debugging.

Signed-off-by: Peter Ujfalusi 
Link: https://lore.kernel.org/r/20200306142839.17910-4-peter.ujfalusi@ti.com
Signed-off-by: Vinod Koul

dmaengine: Add basic debugfs support

2020-03-11T09:25:10+00:00

Via the /sys/kernel/debug/dmaengine/summary users can get information
about the DMA devices and the used channels.

Example output on am654-evm with audio using two channels and after running
dmatest on 4 channels:

dma0 (285c0000.dma-controller): number of channels: 96

dma1 (31150000.dma-controller): number of channels: 267
 dma1chan0    | 2b00000.mcasp:tx
 dma1chan1    | 2b00000.mcasp:rx
 dma1chan2    | in-use
 dma1chan3    | in-use
 dma1chan4    | in-use
 dma1chan5    | in-use

For slave channels we can show the device and the channel name a given
channel is requested.
For non slave devices the only information we know is that the channel is
in use.

DMA drivers can implement the optional dbg_summary_show callback to
provide controller specific information instead of the generic one.

It is easy to extend the generic dmaengine_summary_show() to print
additional information about the used channels.

I have taken the idea from gpiolib and clk subsystems.

Signed-off-by: Peter Ujfalusi 
Link: https://lore.kernel.org/r/20200306142839.17910-2-peter.ujfalusi@ti.com
Signed-off-by: Vinod Koul