If two concurrent threads call pl330_get_desc() when DMAC descriptor
pool is empty it is possible that allocation for one of threads will fail
with message:

kernel: dma-pl330 20078000.dma-controller: pl330_get_desc:2469 ALERT!

Here how that can happen. Thread A calls pl330_get_desc() to get
descriptor. If DMAC descriptor pool is empty pl330_get_desc() allocates
new descriptor on shared pool using add_desc() and then get newly
allocated descriptor using pluck_desc(). At the same time thread B calls
pluck_desc() and take newly allocated descriptor. In that case descriptor
allocation for thread A will fail.

Using on-stack pool for new descriptor allow avoid the issue described.
The patch modify pl330_get_desc() to use on-stack pool for allocation
new descriptors.

Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

amba_id are not supposed to change at runtime. All functions
working with const amba_id. So mark the non-const structs as const.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

Pull dmaengine updates from Vinod Koul:

 - removal of AVR32 support in dw driver as AVR32 is gone

 - new driver for Broadcom stream buffer accelerator (SBA) RAID driver

 - add support for Faraday Technology FTDMAC020 in amba-pl08x driver

 - IOMMU support in pl330 driver

 - updates to bunch of drivers

* tag 'dmaengine-4.13-rc1' of git://git.infradead.org/users/vkoul/slave-dma: (36 commits)
  dmaengine: qcom_hidma: correct API violation for submit
  dmaengine: zynqmp_dma: Remove max len check in zynqmp_dma_prep_memcpy
  dmaengine: tegra-apb: Really fix runtime-pm usage
  dmaengine: fsl_raid: make of_device_ids const.
  dmaengine: qcom_hidma: allow ACPI/DT parameters to be overridden
  dmaengine: fsldma: set BWC, DAHTS and SAHTS values correctly
  dmaengine: Kconfig: Simplify the help text for MXS_DMA
  dmaengine: pl330: Delete unused functions
  dmaengine: Replace WARN_TAINT_ONCE() with pr_warn_once()
  dmaengine: Kconfig: Extend the dependency for MXS_DMA
  dmaengine: mxs: Use %zu for printing a size_t variable
  dmaengine: ste_dma40: Cleanup scatterlist layering violations
  dmaengine: imx-dma: cleanup scatterlist layering violations
  dmaengine: use proper name for the R-Car SoC
  dmaengine: imx-sdma: Fix compilation warning.
  dmaengine: imx-sdma: Handle return value of clk_prepare_enable
  dmaengine: pl330: Add IOMMU support to slave tranfers
  dmaengine: DW DMAC: Handle return value of clk_prepare_enable
  dmaengine: pl08x: use GENMASK() to create bitmasks
  dmaengine: pl08x: Add support for Faraday Technology FTDMAC020
  ...

The functions _queue_empty(), _emit_ADDH(), _emit_NOP(), _emit_STZ()
and _emit_WFE() are not used. Delete them.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

When removing a device with less than 9 IRQs (AMBA_NR_IRQS), we'll get a
big WARN_ON from devres.c because pl330_remove calls devm_free_irqs for
unallocated irqs. Similarly to pl330_probe, check that IRQ number is
present before calling devm_free_irq.

Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

Wire up dma_map_resource() for slave transfers, so that we can let the
PL330 use IOMMU-backed DMA mapping ops on systems with an appropriate
IOMMU and RAM above 4GB, to avoid CPU bounce buffering.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

This driver is now used only on platforms which support device tree, so
it is safe to remove legacy platform data based initialization code.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
For plat-samsung:
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

The static bug finder EBA (http://www.iagoabal.eu/eba/) reported the
following double-lock bug:

    Double lock:
    1. spin_lock_irqsave(pch->lock, flags) at pl330_free_chan_resources:2236;
    2. call to function `pl330_release_channel' immediately after;
    3. call to function `dma_pl330_rqcb' in line 1753;
    4. spin_lock_irqsave(pch->lock, flags) at dma_pl330_rqcb:1505.

I have fixed it as suggested by Marek Szyprowski.

First, I have replaced `pch->lock' with `pl330->lock' in functions
`pl330_alloc_chan_resources' and `pl330_free_chan_resources'. This avoids
the double-lock by acquiring a different lock than `dma_pl330_rqcb'.

NOTE that, as a result, `pl330_free_chan_resources' executes
`list_splice_tail_init' on `pch->work_list' under lock `pl330->lock',
whereas in the rest of the code `pch->work_list' is protected by
`pch->lock'. I don't know if this may cause race conditions. Similarly
`pch->cyclic' is written by `pl330_alloc_chan_resources' under
`pl330->lock' but read by `pl330_tx_submit' under `pch->lock'.

Second, I have removed locking from `pl330_request_channel' and
`pl330_release_channel' functions. Function `pl330_request_channel' is
only called from `pl330_alloc_chan_resources', so the lock is already
held. Function `pl330_release_channel' is called from
`pl330_free_chan_resources', which already holds the lock, and from
`pl330_del'. Function `pl330_del' is called in an error path of
`pl330_probe' and at the end of `pl330_remove', but I assume that there
cannot be concurrent accesses to the protected data at those points.

Signed-off-by: Iago Abal <mail@iagoabal.eu>
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>