Commit Graph

81 Commits

Author SHA1 Message Date
Vladimir Zapolskiy
10b4640833
spi: sh-msiof: Fix bit field overflow writes to TSCR/RSCR
The change fixes a bit field overflow which allows to write to higher
bits while calculating SPI transfer clock and setting BRPS and BRDV
bit fields, the problem is reproduced if 'parent_rate' to 'spi_hz'
ratio is greater than 1024, for instance

  p->min_div      = 2,
  MSO rate        = 33333333,
  SPI device rate = 10000

results in

  k          = 5, i.e. BRDV = 0b100 or 1/32 prescaler output,
  BRPS       = 105,
  TSCR value = 0x6804, thus MSSEL and MSIMM bit fields are non-zero.

Fixes: 65d5665bb2 ("spi: sh-msiof: Update calculation of frequency dividing")
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2018-04-16 15:52:44 +01:00
Geert Uytterhoeven
da779513d3
spi: sh-msiof: Use correct enum for DMA transfer direction
Use enum dma_transfer_direction as required by dmaengine_prep_slave_sg()
instead of enum dma_data_direction.  This won't change behavior in
practice as the enum values are equivalent.

This fixes two warnings when building with clang:
  drivers/spi/spi-sh-msiof.c:755:27: warning: implicit conversion from enumeration
      type 'enum dma_data_direction' to different enumeration type
      'enum dma_transfer_direction' [-Wenum-conversion]
					rx->sgl, rx->nents, DMA_FROM_DEVICE,
							    ^~~~~~~~~~~~~~~
  drivers/spi/spi-sh-msiof.c:772:27: warning: implicit conversion from enumeration
      type 'enum dma_data_direction' to different enumeration type
      'enum dma_transfer_direction' [-Wenum-conversion]
					tx->sgl, tx->nents, DMA_TO_DEVICE,
							    ^~~~~~~~~~~~~

Based on commit 768d59f5d0 ("spi: rspi: use correct enum for DMA
transfer direction").

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Mark Brown <broonie@kernel.org>
2018-03-22 09:38:53 +08:00
Mark Brown
977b06d0a4
Merge remote-tracking branches 'spi/topic/pxa2xx', 'spi/topic/s3c64xx', 'spi/topic/sh-msiof', 'spi/topic/sirf' and 'spi/topic/sun6i' into spi-next 2018-01-26 17:57:31 +00:00
Geert Uytterhoeven
89434c3c35
spi: sh-msiof: Fix timeout failures for TX-only DMA transfers
When using RX (with or without TX), the DMA interrupt triggers
completion when the RX FIFO has been emptied, i.e. after the full
transfer has finished.

However, when using TX without RX, the DMA interrupt triggers completion
as soon as the DMA engine has filled the TX FIFO, i.e. before the full
transfer has finished.  Then sh_msiof_modify_ctr_wait() will spin until
the transfer has really finished and the TFSE bit is cleared, for at
most 1 ms.  For slow speeds and/or large transfers, this may cause
timeouts and transfer failures:

    spi_sh_msiof e6e10000.spi: failed to shut down hardware
    74x164 spi2.0: SPI transfer failed: -110
    spi_master spi2: failed to transfer one message from queue
    74x164 spi2.0: Failed writing: -110

Fix this by waiting explicitly until the TX FIFO has been emptied.

Based on a patch in the BSP by Hiromitsu Yamasaki.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
2018-01-03 17:42:42 +00:00
Geert Uytterhoeven
b8761434bd
spi: sh-msiof: Implement cs-gpios configuration
The current support for GPIO chip selects assumes the GPIOs have been
configured by platform code or the boot loader.  This includes pinmux
setup and GPIO direction.  Hence it does not work as expected when just
described in DT using the "cs-gpios" property.

Fix this by:
  1. using devm_gpiod_get_index() to request the GPIO, and thus
     configure pinmux, if needed,
  2. configuring the GPIO direction is the spi_master.setup() callback.

Use gpio_is_valid() instead of a check on positive numbers.

Note that when using GPIO chip selects, at least one native chip select
must be left unused, as that native chip select will be driven anyway,
and (global) native chip select polarity must be taken into account.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
2017-12-14 11:46:14 +00:00
Geert Uytterhoeven
9cce882bed
spi: sh-msiof: Extend support to 3 native chip selects
Currently only the MSIOF_SYNC signal can be used as a native chip
select.  Extend support to up to 3 native chipselects using the
MSIOF_SS1 and MSIOF_SS2 signals.

Inspired by a patch in the BSP by Hiromitsu Yamasaki.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
2017-12-14 11:46:07 +00:00
Geert Uytterhoeven
7ff0b53c40
spi: sh-msiof: Avoid writing to registers from spi_master.setup()
The spi_master.setup() callback must not change configuration registers,
as that could corrupt I/O that is in progress for other SPI slaves.

The only exception is the configuration of the native chip select
polarity in SPI master mode, as a wrong chip select polarity will cause
havoc during all future transfers to any other SPI slave.

Hence stop writing to registers in sh_msiof_spi_setup(), unless it is
the first call for a controller using a native chip select, or unless
native chip select polarity has changed (note that you'll loose anyway
if I/O is in progress).  Even then, only do what is strictly necessary,
instead of calling sh_msiof_spi_set_pin_regs().

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
2017-12-14 11:46:02 +00:00
Geert Uytterhoeven
5d8e614f6c
spi: sh-msiof: Use dev_warn_once() instead of open-coding
Use the helper introduced by commit e135303bd5 ("device: Add
dev_<level>_once variants") instead of open-coding the same
functionality.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
2017-11-30 16:57:06 +00:00
Mark Brown
abbdb5ce31
Merge remote-tracking branches 'spi/topic/sh-msiof', 'spi/topic/slave', 'spi/topic/spreadtrum' and 'spi/topic/tegra114' into spi-next 2017-11-10 21:33:51 +00:00
Colin Ian King
6ae6678344
spi: sh-msiof: remove redundant pointer dev
The pointer dev is assigned but never read, hence it is redundant
and can be removed. Cleans up clang warning:

drivers/spi/spi-sh-msiof.c:1198:2: warning: Value stored to 'dev'
is never read

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2017-11-03 17:21:34 +00:00
Hiromitsu Yamasaki
36735783fd
spi: sh-msiof: Fix DMA transfer size check
DMA supports 32-bit words only,
even if BITLEN1 of SITMDR2 register is 16bit.

Fixes: b0d0ce8b6b ("spi: sh-msiof: Add DMA support")
Signed-off-by: Hiromitsu Yamasaki <hiromitsu.yamasaki.ym@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2017-11-02 11:25:44 +00:00
Geert Uytterhoeven
ecb1596aa2 spi: sh-msiof: Use of_device_get_match_data() helper
Use the of_device_get_match_data() helper instead of open coding.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
2017-10-04 15:48:20 +01:00
Fabrizio Castro
bdacfc7b62 spi: sh-msiof: Add compatible strings for r8a774[35]
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2017-09-25 17:13:34 +01:00
Geert Uytterhoeven
61a8dec502 spi: sh-msiof: Limit minimum divider on R-Car Gen3
On R-Car Gen3 SoCs (excluding R-Car H3 ES1.x, which cannot be used for
SPI due to a hardware erratum), BRPS x BRDV = 1/1 is an invalid divider
setting.
Implement this limitation using an SoC/family-specific minimum divider.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
2017-07-17 12:09:59 +01:00
Hisashi Nakamura
cf9e4784f3 spi: sh-msiof: Add slave mode support
Add slave mode support to the MSIOF driver, in both PIO and DMA mode.

For now this only supports the transmission of messages with a size
that is known in advance.

Signed-off-by: Hisashi Nakamura <hisashi.nakamura.ak@renesas.com>
Signed-off-by: Hiromitsu Yamasaki <hiromitsu.yamasaki.ym@renesas.com>
[geert: Timeout handling cleanup, spi core integration, cancellation,
	rewording]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
2017-05-26 13:11:54 +01:00
Geert Uytterhoeven
e7ad4a7336 spi: sh-msiof: Remove useless memory allocation failure message
Printing an error on memory allocation failure is unnecessary.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
2017-01-04 17:39:37 +00:00
Simon Horman
264c3e8de4 spi: sh-msiof: Do not use C++ style comment
4286db8456 ("spi: sh-msiof: Add R-Car Gen 2 and 3 fallback bindings")
added a C++ style comment. This is not in keeping with the style used
for comments elsewhere in this fine. Update it accordingly.

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Mark Brown <broonie@kernel.org>
2016-12-20 11:40:57 +00:00
Simon Horman
4286db8456 spi: sh-msiof: Add R-Car Gen 2 and 3 fallback bindings
In the case of Renesas R-Car hardware we know that there are generations of
SoCs, e.g. Gen 2 and Gen 3. But beyond that it's not clear what the
relationship between IP blocks might be. For example, I believe that
r8a7790 is older than r8a7791 but that doesn't imply that the latter is a
descendant of the former or vice versa.

We can, however, by examining the documentation and behaviour of the
hardware at run-time observe that the current driver implementation appears
to be compatible with the IP blocks on SoCs within a given generation.

For the above reasons and convenience when enabling new SoCs a
per-generation fallback compatibility string scheme is being adopted for
drivers for Renesas SoCs.

Also:
* Deprecate renesas,sh-msiof. It seems poorly named as it is only
  compatible with SH-Mobile. It also appears unused in mainline.

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
2016-12-14 17:38:18 +00:00
Geert Uytterhoeven
eb51cffa74 spi: sh-msiof: Add support for R-Car M3-W
MSIOF in R-Car M3-W (r8a7796) is handled fine by the existing driver.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
2016-11-21 18:30:36 +00:00
Geert Uytterhoeven
c3ccf357c3 spi: sh-msiof: Avoid invalid clock generator parameters
The conversion from a look-up table to a calculation for clock generator
parameters forgot to take into account that BRDV x 1/1 is valid only if
BRPS is x 1/1 or x 1/2, leading to undefined behavior (e.g. arbitrary
clock rates).

This limitation is documented for the MSIOF module in all supported
SH/R-Mobile and R-Car Gen2/Gen3 ARM SoCs.

Tested on r8a7791/koelsch and r8a7795/salvator-x.

Fixes: 65d5665bb2 ("spi: sh-msiof: Update calculation of frequency dividing")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
2016-08-05 11:46:07 +01:00
Geert Uytterhoeven
a6802cc05f spi: sh-msiof: Remove sh_msiof_spi_priv.chipdata
After probe time, the pointer to the sh_msiof_chipdata structure in the
sh_msiof_spi_priv structure is used only for checking the SPI master flags.
As these are also available in the spi_master structure, convert the
users to access those, and remove the pointer.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
2016-06-22 14:14:38 +01:00
Koji Matsuoka
fe78d0b769 spi: sh-msiof: Fix FIFO size to 64 word from 256 word
The upper limit of Tx/Rx FIFO size is 64 word by the
specification of H/W. This patch corrects to 64 word from 256 word.

Signed-off-by: Koji Matsuoka <koji.matsuoka.xm@renesas.com>
Signed-off-by: Yoshihiro Kaneko <ykaneko0929@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
2015-08-31 14:42:40 +01:00
Geert Uytterhoeven
f6d1b3e20a spi: sh-msiof: Remove obsolete spi_r8a779x_msiof platform_device_id entries
Since commit a483dcbfa2 ("ARM: shmobile: lager: Remove legacy
board support"), R-Car Gen2 SoCs are only supported in generic DT-only
ARM multi-platform builds.  The driver doesn't need to match platform
devices by name anymore, hence remove the corresponding
platform_device_id entry.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-07-07 13:16:47 +01:00
Krzysztof Kozlowski
3789c85206 spi: sh-msiof: Constify platform_device_id
The platform_device_id is not modified by the driver and core uses it as
const.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-05-01 17:38:58 +01:00
Arnd Bergmann
e95ddb5bda spi: sh-msiof: remove slave_id settings for DMAEngine
Current sh-msiof sets dma_slave_config :: slave_id field for DMAEngine,
but it is no longer needed. Let's remove it.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2015-02-23 16:13:18 +05:30
Nicholas Mc Guire
19f0ad0942 spi: sh-msiof: cleanup wait_for_completion return handling
return type of wait_for_completion_timeout is unsigned long not int, this
patch uses the return value of wait_for_completion_timeout in the condition
directly rather than assigning it to an incorrect type variable.

Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-02-04 20:52:53 +00:00
Nobuhiro Iwamatsu
65d5665bb2 spi: sh-msiof: Update calculation of frequency dividing
sh-msiof of frequency dividing does not perform the calculation, driver have
to manage setting value in the table. It is not possible to set frequency
dividing value close to the actual data in this way. This changes from
frequency dividing of table management to setting by calculation.
This driver is able to set a value close to the actual data.

Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-02-02 20:03:39 +00:00
Geert Uytterhoeven
c8935ef0f2 spi: sh-msiof: Use async pm_runtime_put() in sh_msiof_spi_setup()
There's no need to use the synchronous version.

Reported-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-07 17:30:25 +00:00
Mark Brown
1285c3fefa Linux 3.19-rc3
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Merge tag 'v3.19-rc3' into spi-sh-msiof

Linux 3.19-rc3
2015-01-07 17:30:17 +00:00
Mark Brown
6b038c8d2b Merge remote-tracking branch 'spi/fix/msiof' into spi-sh-msiof
Conflicts:
	drivers/spi/spi-sh-msiof.c
2015-01-06 11:06:46 +00:00
Yoshihiro Shimoda
6d40530e47 spi: sh-msiof: fix MDR1_FLD_MASK value
Since the FLD bit field is bit[3:2], the MDR1_FLD_MASK value should
be 0x0000000c.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-06 11:04:33 +00:00
Mark Brown
ee4629f5b2 Merge remote-tracking branches 'spi/fix/img-spfi' and 'spi/fix/msiof' into spi-linus 2014-12-24 12:57:54 +00:00
Yoshihiro Shimoda
3110628d89 spi: sh-msiof: Configure MSIOF sync signal timing in device tree
The MSIOF controller has DTDL and SYNCDL in SITMDR1 register. So,
this patch adds new properties like the following commit:
  d0fb47a523
  (spi: fsl-espi: Configure FSL eSPI CSBEF and CSAFT)

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2014-12-24 12:31:17 +00:00
Hisashi Nakamura
015760563e spi: sh-msiof: Add runtime PM lock in initializing
SH-MSIOF driver is enabled autosuspend API of spi framework.
But autosuspend framework doesn't work during initializing.
So runtime PM lock is added in SH-MSIOF driver initializing.

Fixes: e2a0ba547b (spi: sh-msiof: Convert to spi core auto_runtime_pm framework)
Signed-off-by: Hisashi Nakamura <hisashi.nakamura.ak@renesas.com>
Signed-off-by: Yoshihiro Kaneko <ykaneko0929@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
2014-12-15 17:36:45 +00:00
Wolfram Sang
14ac00e033 spi: drop owner assignment from platform_drivers
A platform_driver does not need to set an owner, it will be populated by the
driver core.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-10-20 16:21:36 +02:00
Geert Uytterhoeven
e221cc99be spi: sh-msiof: Add support for new R-Car Gen2 SoCs
Add support for MSIOF in:
  - r8a7792 (R-Car V2H)
  - r8a7793 (R-Car M2-N)
  - r8a7794 (R-Car E2)

r8a7791 is now called "R-Car M2-W".

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-08-28 19:17:46 +01:00
Geert Uytterhoeven
7a9f957b39 spi: sh-msiof: Fix transmit-only DMA transfers
Fix tx/rx mixup, which broke transmit-only transfers.

Introduced by commit 4240305f7cbdc7782aa8bc40cc702775d9ac0839
("spi: sh-msiof: Fix leaking of unused DMA descriptors").

Reported-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-08-16 17:14:30 -05:00
Geert Uytterhoeven
a5e7c719fe spi: sh-msiof: Return early in sh_msiof_dma_once() where possible
Reported-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-08-16 17:14:30 -05:00
Geert Uytterhoeven
a6be4de6a2 spi: sh-msiof: Add DT support to DMA setup
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-08-16 17:14:30 -05:00
Geert Uytterhoeven
52fba2b85d spi: sh-msiof: Configure DMA slave bus width
The new Renesas R-Car Gen2 DMA Controller driver (rcar-dmac) requires
explicit configuration of the DMA slave bus width.
Hardcode the DMA transfer size to 4 bytes, as MSIOF DMA is limited to
32-bit words.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-08-16 17:14:30 -05:00
Geert Uytterhoeven
3e81b59208 spi: sh-msiof: Fix leaking of unused DMA descriptors
If dmaengine_prep_slave_sg() or dmaengine_submit() fail, we may leak
unused DMA descriptors.

As per Documentation/dmaengine.txt, once a DMA descriptor has been
obtained, it must be submitted. Hence:
  - First prepare and submit all DMA descriptors,
  - Prepare the SPI controller for DMA,
  - Start DMA by calling dma_async_issue_pending(),
  - Make sure to call dmaengine_terminate_all() on all descriptors that
    haven't completed.

Reported-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-08-16 17:13:14 -05:00
Geert Uytterhoeven
5dabcf2f27 spi: sh-msiof: Use correct device for DMA mapping with IOMMU
To function correctly in the presence of an IOMMU, the DMA buffers must be
mapped using the DMA channel's device instead of the MSIOF platform
device's device.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-07-16 23:19:34 +01:00
Geert Uytterhoeven
279d2378c9 spi: sh-msiof: Handle dmaengine_prep_slave_single() failures gracefully
As typically a shmobile SoC has less DMA channels than devices that can use
DMA, we may want to prioritize access to the DMA channels in the future.
This means that dmaengine_prep_slave_single() may start failing
arbitrarily.

Handle dmaengine_prep_slave_single() failures gracefully by falling back to
PIO. This requires moving DMA-specific configuration of the MSIOF device
after the call(s) to dmaengine_prep_slave_single().

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-07-16 22:41:51 +01:00
Geert Uytterhoeven
b0d0ce8b6b spi: sh-msiof: Add DMA support
Add DMA support to the MSIOF driver using platform data.

As MSIOF DMA is limited to 32-bit words (requiring byte/wordswapping for
smaller wordsizes), and the group length is limited to 256 words, DMA is
performed on two fixed pages, allocated and mapped at driver initialization
time.

Performance figures (in Mbps) on r8a7791/koelsch at different SPI clock
frequencies for 1024-byte and 4096-byte transfers:

                   1024 bytes           4096 bytes
  -  3.25 MHz: PIO  2.1, DMA  2.6 | PIO  2.8, DMA  3.1
  -  6.5  MHz: PIO  3.2, DMA  4.4 | PIO  5.0, DMA  5.9
  - 13    MHz: PIO  4.2, DMA  6.6 | PIO  8.2, DMA 10.7
  - 26    MHz: PIO  5.9, DMA 10.4 | PIO 12.4, DMA 18.4

Note that DMA is only faster than PIO for transfers that exceed the FIFO
size (typically 64 words / 256 bytes).

Also note that large transfers (larger than the group length for DMA, or
larger than the FIFO size for PIO), should use cs-gpio (with the
appropriate pinmux setup), as the hardware chipselect will be deasserted in
between chunks.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-30 19:54:57 +01:00
Geert Uytterhoeven
0312d59130 spi: sh-msiof: Refactor sh_msiof_transfer_one()
- Move buffer pointer and length setup to the top,
  - Make unsigned values unsigned,
  - Loop over words and increment pointers instead of recalculating them,
    which allows to kill bytes_done.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-21 11:17:36 +01:00
Geert Uytterhoeven
75b82e23a4 spi: sh-msiof: Improve transfer error handling
- Add a timeout when waiting for the transfer complete interrupt,
  - If sh_msiof_spi_stop() fails, there's no need to clear IER, as the
    interrupt handler has already done that,
  - Propagate transfer failures in sh_msiof_transfer_one().

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-21 11:17:36 +01:00
Geert Uytterhoeven
76c02e7161 spi: sh-msiof: Extract sh_msiof_spi_{start,stop}() helpers
Based on an old patch by Guennadi Liakhovetski <g.liakhovetski@gmx.de>

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-21 11:17:35 +01:00
Geert Uytterhoeven
2e2b36872d spi: sh-msiof: Add more register documentation
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-21 11:17:34 +01:00
Jingoo Han
1e8231b79c spi: sh-msiof: remove unnecessary OOM messages
The site-specific OOM messages are unnecessary, because they
duplicate the MM subsystem generic OOM message.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-04-29 12:01:41 -07:00
Mark Brown
81235b4ea3 Merge remote-tracking branches 'spi/topic/s3c64xx', 'spi/topic/sc18is602', 'spi/topic/sh-hspi', 'spi/topic/sh-msiof', 'spi/topic/sh-sci', 'spi/topic/sirf' and 'spi/topic/spidev' into spi-next 2014-03-30 00:51:34 +00:00