linux-stable.git/drivers/dma/dw, branch linux-5.4.y Linux kernel stable tree dmaengine: dw: Make it dependent to HAS_IOMEM 2021-04-21T10:56:13+00:00 Andy Shevchenko andriy.shevchenko@linux.intel.com 2021-03-24T14:17:57+00:00 09db44ad36b0fce4a4c84607c32d1c613a5c7e4c [ Upstream commit 88cd1d6191b13689094310c2405394e4ce36d061 ] Some architectures do not provide devm_*() APIs. Hence make the driver dependent on HAVE_IOMEM. Fixes: dbde5c2934d1 ("dw_dmac: use devm_* functions to simplify code") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Link: https://lore.kernel.org/r/20210324141757.24710-1-andriy.shevchenko@linux.intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 88cd1d6191b13689094310c2405394e4ce36d061 ]

Some architectures do not provide devm_*() APIs. Hence make the driver
dependent on HAVE_IOMEM.

Fixes: dbde5c2934d1 ("dw_dmac: use devm_* functions to simplify code")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/20210324141757.24710-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
dmaengine: dw: Activate FIFO-mode for memory peripherals only 2020-10-29T08:58:09+00:00 Serge Semin Sergey.Semin@baikalelectronics.ru 2020-07-31T20:08:23+00:00 18ec92b1ce2975f8d27af868084c70835b86ace4 [ Upstream commit 6d9459d04081c796fc67c2bb771f4e4ebb5744c4 ] CFGx.FIFO_MODE field controls a DMA-controller "FIFO readiness" criterion. In other words it determines when to start pushing data out of a DW DMAC channel FIFO to a destination peripheral or from a source peripheral to the DW DMAC channel FIFO. Currently FIFO-mode is set to one for all DW DMAC channels. It means they are tuned to flush data out of FIFO (to a memory peripheral or by accepting the burst transaction requests) when FIFO is at least half-full (except at the end of the block transfer, when FIFO-flush mode is activated) and are configured to get data to the FIFO when it's at least half-empty. Such configuration is a good choice when there is no slave device involved in the DMA transfers. In that case the number of bursts per block is less than when CFGx.FIFO_MODE = 0 and, hence, the bus utilization will improve. But the latency of DMA transfers may increase when CFGx.FIFO_MODE = 1, since DW DMAC will wait for the channel FIFO contents to be either half-full or half-empty depending on having the destination or the source transfers. Such latencies might be dangerous in case if the DMA transfers are expected to be performed from/to a slave device. Since normally peripheral devices keep data in internal FIFOs, any latency at some critical moment may cause one being overflown and consequently losing data. This especially concerns a case when either a peripheral device is relatively fast or the DW DMAC engine is relatively slow with respect to the incoming data pace. In order to solve problems, which might be caused by the latencies described above, let's enable the FIFO half-full/half-empty "FIFO readiness" criterion only for DMA transfers with no slave device involved. Thanks to the commit 99ba8b9b0d97 ("dmaengine: dw: Initialize channel before each transfer") we can freely do that in the generic dw_dma_initialize_chan() method. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20200731200826.9292-3-Sergey.Semin@baikalelectronics.ru Signed-off-by: Vinod Koul <vkoul@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 6d9459d04081c796fc67c2bb771f4e4ebb5744c4 ]

CFGx.FIFO_MODE field controls a DMA-controller "FIFO readiness" criterion.
In other words it determines when to start pushing data out of a DW
DMAC channel FIFO to a destination peripheral or from a source
peripheral to the DW DMAC channel FIFO. Currently FIFO-mode is set to one
for all DW DMAC channels. It means they are tuned to flush data out of
FIFO (to a memory peripheral or by accepting the burst transaction
requests) when FIFO is at least half-full (except at the end of the block
transfer, when FIFO-flush mode is activated) and are configured to get
data to the FIFO when it's at least half-empty.

Such configuration is a good choice when there is no slave device involved
in the DMA transfers. In that case the number of bursts per block is less
than when CFGx.FIFO_MODE = 0 and, hence, the bus utilization will improve.
But the latency of DMA transfers may increase when CFGx.FIFO_MODE = 1,
since DW DMAC will wait for the channel FIFO contents to be either
half-full or half-empty depending on having the destination or the source
transfers. Such latencies might be dangerous in case if the DMA transfers
are expected to be performed from/to a slave device. Since normally
peripheral devices keep data in internal FIFOs, any latency at some
critical moment may cause one being overflown and consequently losing
data. This especially concerns a case when either a peripheral device is
relatively fast or the DW DMAC engine is relatively slow with respect to
the incoming data pace.

In order to solve problems, which might be caused by the latencies
described above, let's enable the FIFO half-full/half-empty "FIFO
readiness" criterion only for DMA transfers with no slave device involved.
Thanks to the commit 99ba8b9b0d97 ("dmaengine: dw: Initialize channel
before each transfer") we can freely do that in the generic
dw_dma_initialize_chan() method.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200731200826.9292-3-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
dmaengine: dw: Add DMA-channels mask cell support 2020-10-29T08:58:09+00:00 Serge Semin Sergey.Semin@baikalelectronics.ru 2020-07-31T20:08:26+00:00 190bce292b734de5f164515b587d352b9e26441f [ Upstream commit e8ee6c8cb61b676f1a2d6b942329e98224bd8ee9 ] DW DMA IP-core provides a way to synthesize the DMA controller with channels having different parameters like maximum burst-length, multi-block support, maximum data width, etc. Those parameters both explicitly and implicitly affect the channels performance. Since DMA slave devices might be very demanding to the DMA performance, let's provide a functionality for the slaves to be assigned with DW DMA channels, which performance according to the platform engineer fulfill their requirements. After this patch is applied it can be done by passing the mask of suitable DMA-channels either directly in the dw_dma_slave structure instance or as a fifth cell of the DMA DT-property. If mask is zero or not provided, then there is no limitation on the channels allocation. For instance Baikal-T1 SoC is equipped with a DW DMAC engine, which first two channels are synthesized with max burst length of 16, while the rest of the channels have been created with max-burst-len=4. It would seem that the first two channels must be faster than the others and should be more preferable for the time-critical DMA slave devices. In practice it turned out that the situation is quite the opposite. The channels with max-burst-len=4 demonstrated a better performance than the channels with max-burst-len=16 even when they both had been initialized with the same settings. The performance drop of the first two DMA-channels made them unsuitable for the DW APB SSI slave device. No matter what settings they are configured with, full-duplex SPI transfers occasionally experience the Rx FIFO overflow. It means that the DMA-engine doesn't keep up with incoming data pace even though the SPI-bus is enabled with speed of 25MHz while the DW DMA controller is clocked with 50MHz signal. There is no such problem has been noticed for the channels synthesized with max-burst-len=4. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200731200826.9292-6-Sergey.Semin@baikalelectronics.ru Signed-off-by: Vinod Koul <vkoul@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit e8ee6c8cb61b676f1a2d6b942329e98224bd8ee9 ]

DW DMA IP-core provides a way to synthesize the DMA controller with
channels having different parameters like maximum burst-length,
multi-block support, maximum data width, etc. Those parameters both
explicitly and implicitly affect the channels performance. Since DMA slave
devices might be very demanding to the DMA performance, let's provide a
functionality for the slaves to be assigned with DW DMA channels, which
performance according to the platform engineer fulfill their requirements.
After this patch is applied it can be done by passing the mask of suitable
DMA-channels either directly in the dw_dma_slave structure instance or as
a fifth cell of the DMA DT-property. If mask is zero or not provided, then
there is no limitation on the channels allocation.

For instance Baikal-T1 SoC is equipped with a DW DMAC engine, which first
two channels are synthesized with max burst length of 16, while the rest
of the channels have been created with max-burst-len=4. It would seem that
the first two channels must be faster than the others and should be more
preferable for the time-critical DMA slave devices. In practice it turned
out that the situation is quite the opposite. The channels with
max-burst-len=4 demonstrated a better performance than the channels with
max-burst-len=16 even when they both had been initialized with the same
settings. The performance drop of the first two DMA-channels made them
unsuitable for the DW APB SSI slave device. No matter what settings they
are configured with, full-duplex SPI transfers occasionally experience the
Rx FIFO overflow. It means that the DMA-engine doesn't keep up with
incoming data pace even though the SPI-bus is enabled with speed of 25MHz
while the DW DMA controller is clocked with 50MHz signal. There is no such
problem has been noticed for the channels synthesized with
max-burst-len=4.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200731200826.9292-6-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
dmaengine: dw: Initialize channel before each transfer 2020-07-22T07:33:02+00:00 Andy Shevchenko andriy.shevchenko@linux.intel.com 2020-07-05T11:56:20+00:00 e6b46f01d9951bce04ec87b8df92ee8bb48802cb [ Upstream commit 99ba8b9b0d9780e9937eb1d488d120e9e5c2533d ] In some cases DMA can be used only with a consumer which does runtime power management and on the platforms, that have DMA auto power gating logic (see comments in the drivers/acpi/acpi_lpss.c), may result in DMA losing its context. Simple mitigation of this issue is to initialize channel each time the consumer initiates a transfer. Fixes: cfdf5b6cc598 ("dw_dmac: add support for Lynxpoint DMA controllers") Reported-by: Tsuchiya Yuto <kitakar@gmail.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=206403 Link: https://lore.kernel.org/r/20200705115620.51929-1-andriy.shevchenko@linux.intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 99ba8b9b0d9780e9937eb1d488d120e9e5c2533d ]

In some cases DMA can be used only with a consumer which does runtime power
management and on the platforms, that have DMA auto power gating logic
(see comments in the drivers/acpi/acpi_lpss.c), may result in DMA losing
its context. Simple mitigation of this issue is to initialize channel
each time the consumer initiates a transfer.

Fixes: cfdf5b6cc598 ("dw_dmac: add support for Lynxpoint DMA controllers")
Reported-by: Tsuchiya Yuto <kitakar@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=206403
Link: https://lore.kernel.org/r/20200705115620.51929-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
dmaengine: dw: platform: Mark 'hclk' clock optional 2020-01-17T18:48:49+00:00 Andy Shevchenko andriy.shevchenko@linux.intel.com 2019-09-24T08:51:16+00:00 8fa2c2ca23579e299d4c38c0692877353c94e9d7 commit f27c22736d133baff0ab3fdc7b015d998267d817 upstream. On some platforms the clock can be fixed rate, always running one and there is no need to do anything with it. In order to support those platforms, switch to use optional clock. Fixes: f8d9ddbc2851 ("dmaengine: dw: platform: Enable iDMA 32-bit on Intel Elkhart Lake") Depends-on: 60b8f0ddf1a9 ("clk: Add (devm_)clk_get_optional() functions") Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Link: https://lore.kernel.org/r/20190924085116.83683-1-andriy.shevchenko@linux.intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit f27c22736d133baff0ab3fdc7b015d998267d817 upstream.

On some platforms the clock can be fixed rate, always running one and
there is no need to do anything with it.

In order to support those platforms, switch to use optional clock.

Fixes: f8d9ddbc2851 ("dmaengine: dw: platform: Enable iDMA 32-bit on Intel Elkhart Lake")
Depends-on: 60b8f0ddf1a9 ("clk: Add (devm_)clk_get_optional() functions")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/20190924085116.83683-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
dmaengine: dw: platform: Split OF helpers to separate module 2019-08-21T04:11:28+00:00 Andy Shevchenko andriy.shevchenko@linux.intel.com 2019-08-20T13:15:46+00:00 f5e84eae7956c694d27ddaba7113fe7d1174eff7 For better maintenance split OF helpers to the separate module. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20190820131546.75744-11-andriy.shevchenko@linux.intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org> 
For better maintenance split OF helpers to the separate module.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20190820131546.75744-11-andriy.shevchenko@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
dmaengine: dw: platform: Split ACPI helpers to separate module 2019-08-21T04:11:28+00:00 Andy Shevchenko andriy.shevchenko@linux.intel.com 2019-08-20T13:15:45+00:00 b685fe26e9af7318d73bf50af659a282d188a3e5 For better maintenance split ACPI helpers to the separate module. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20190820131546.75744-10-andriy.shevchenko@linux.intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org> 
For better maintenance split ACPI helpers to the separate module.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20190820131546.75744-10-andriy.shevchenko@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
dmaengine: dw: platform: Move handle check to dw_dma_acpi_controller_register() 2019-08-21T04:11:28+00:00 Andy Shevchenko andriy.shevchenko@linux.intel.com 2019-08-20T13:15:44+00:00 84da042e702347c186b84d9cc2e766f83e1814d6 Move ACPI handle check to the dw_dma_acpi_controller_register(). While here, convert it to has_acpi_companion() which is recommended way. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20190820131546.75744-9-andriy.shevchenko@linux.intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org> 
Move ACPI handle check to the dw_dma_acpi_controller_register().

While here, convert it to has_acpi_companion() which is recommended way.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20190820131546.75744-9-andriy.shevchenko@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
dmaengine: dw: platform: Switch to acpi_dma_controller_register() 2019-08-21T04:11:28+00:00 Andy Shevchenko andriy.shevchenko@linux.intel.com 2019-08-20T13:15:43+00:00 e7b8514e4d68bec21fc6385fa0a66797ddc34ac9 There is a possibility to have registered ACPI DMA controller while it has been gone already. To avoid the potential crash, move to non-managed acpi_dma_controller_register(). Fixes: 42c91ee71d6d ("dw_dmac: add ACPI support") Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20190820131546.75744-8-andriy.shevchenko@linux.intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org> 
There is a possibility to have registered ACPI DMA controller
while it has been gone already.

To avoid the potential crash, move to non-managed
acpi_dma_controller_register().

Fixes: 42c91ee71d6d ("dw_dmac: add ACPI support")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20190820131546.75744-8-andriy.shevchenko@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
dmaengine: dw: platform: Use devm_platform_ioremap_resource() 2019-08-21T04:11:28+00:00 Andy Shevchenko andriy.shevchenko@linux.intel.com 2019-08-20T13:15:42+00:00 a9c56721d6ae99b22e983d0722e6b1b53a11dd59 Use the new helper that wraps the calls to platform_get_resource() and devm_ioremap_resource() together. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20190820131546.75744-7-andriy.shevchenko@linux.intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org> 
Use the new helper that wraps the calls to platform_get_resource()
and devm_ioremap_resource() together.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20190820131546.75744-7-andriy.shevchenko@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>