There is no need to call spi_master_put() if spi_alloc_master()
failed, it should return -ENOMEM directly.
Signed-off-by: Peng Fan <fanpeng@loongson.cn>
Link: https://lore.kernel.org/r/1594111842-9468-1-git-send-email-fanpeng@loongson.cnSigned-off-by: Mark Brown <broonie@kernel.org>

Merge series "Add Renesas RPC-IF support" from Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>:

Hello!

Here's a set of 2 patches against Linus' repo. Renesas Reduced Pin Count
Interface (RPC-IF) allows a SPI flash or HyperFlash connected to the SoC
to be accessed via the external address space read mode or the manual mode.
The memory controller driver for RPC-IF registers either SPI or HyperFLash
subdevice, depending on the contents of the device tree subnode; it also
provides the abstract "back end" API that can be used by the "front end"
SPI/MTD drivers to talk to the real hardware...

Based on the original patch by Mason Yang <masonccyang@mxic.com.tw>.

[1/2] dt-bindings: memory: document Renesas RPC-IF bindings
[2/2] memory: add Renesas RPC-IF driver

MBR, Sergei

Merge series "spi: bcm2835: Interrupt-handling optimisations" from Robin Murphy <robin.murphy@arm.com>:

Hi all,

Although Florian was concerned about a trivial inline check to deal with
shared IRQs adding overhead, the reality is that it would be so small as
to not be worth even thinking about unless the driver was already tuned
to squeeze out every last cycle. And a brief look over the code shows
that that clearly isn't the case.

This is an example of some of the easy low-hanging fruit that jumps out
just from code inspection. Based on disassembly and ARM1176 cycle
timings, patch #2 should save the equivalent of 2-3 shared interrupt
checks off the critical path in all cases, and patch #3 possibly up to
about 100x more. I don't have any means to test these patches, let alone
measure performance, so they're only backed by the principle that less
code - and in particular fewer memory accesses - is almost always
better.

There is almost certainly a *lot* more to be had from careful use of
relaxed I/O accessors, not doing a read-modify-write of CS at every
reset, tweaking the loops further to avoid unnecessary writebacks to
variables, and so on. However since I'm not invested in this personally
I'm not going to pursue it any further; I'm throwing these patches out
as more of a demonstration to back up my original drive-by review
comments, so if anyone want to pick them up and run with them then
please do so.

Robin.

Robin Murphy (3):
  spi: bcm3835: Tidy up bcm2835_spi_reset_hw()
  spi: bcm2835: Micro-optimise IRQ handler
  spi: bcm2835: Micro-optimise FIFO loops

 drivers/spi/spi-bcm2835.c | 45 +++++++++++++++++++--------------------
 1 file changed, 22 insertions(+), 23 deletions(-)

--
2.23.0.dirty

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

This switches the Lantiq SSC driver over to use GPIO descriptor
handling in the core.

The driver was already utilizing the core to look up and request
GPIOs from the device tree so this is a pretty small change
just switching it over to use descriptors directly instead.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Link: https://lore.kernel.org/r/20200625202149.209276-1-linus.walleij@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>

This converts the IMG SPFI SPI driver to use GPIO descriptors
as obtained from the core instead of GPIO numbers.

The driver was already relying on the core code to look up
the GPIO numbers from the device tree and allocate memory for
storing state etc. By moving to use descriptors handled by
the core we can delete the setup/cleanup functions and
the device state handler that were only dealing with this.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Ionela Voinescu <ionela.voinescu@imgtec.com>
Cc: Sifan Naeem <sifan.naeem@imgtec.com>
Link: https://lore.kernel.org/r/20200625201422.208640-1-linus.walleij@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>

The Nuvoton PSPI driver already uses the core to handle GPIO
chip selects but is using the old GPIO number method and
retrieveing the GPIOs in the probe() call.

Switch it over to using GPIO descriptors saving a bunch of
code and modernizing it.

Compile tested med ARMv7 multiplatform config augmented
with the Nuvoton arch and this driver.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Tomer Maimon <tmaimon77@gmail.com>
Link: https://lore.kernel.org/r/20200625225759.273911-1-linus.walleij@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>

On some SPI controllers (like spi-geni-qcom) setting the chip select
is a heavy operation.  For instance on spi-geni-qcom, with the current
code, is was measured as taking upwards of 20 us.  Even on SPI
controllers that aren't as heavy, setting the chip select is at least
something like a MMIO operation over some peripheral bus which isn't
as fast as a RAM access.

While it would be good to find ways to mitigate problems like this in
the drivers for those SPI controllers, it can also be noted that the
SPI framework could also help out.  Specifically, in some situations,
we can see the SPI framework calling the driver's set_cs() with the
same parameter several times in a row.  This is specifically observed
when looking at the way the Chrome OS EC SPI driver (cros_ec_spi)
works but other drivers likely trip it to some extent.

Let's solve this by caching the chip select state in the core and only
calling into the controller if there was a change.  We check not only
the "enable" state but also the chip select mode (active high or
active low) since controllers may care about both the mode and the
enable flag in their callback.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200629164103.1.Ied8e8ad8bbb2df7f947e3bc5ea1c315e041785a2@changeidSigned-off-by: Mark Brown <broonie@kernel.org>

The field mspi->reg_base is annotated as an __iomem pointer. Good.

However, this field is often assigned to a temporary variable:
before being used. For example:
	struct fsl_spi_reg *reg_base = mspi->reg_base;

But this variable is missing the __iomem annotation.
So, add the missing __iomem and make sparse & the bot happier.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Link: https://lore.kernel.org/r/20200622162611.83694-1-luc.vanoostenryck@gmail.comSigned-off-by: Mark Brown <broonie@kernel.org>

Add the memory driver for Renesas RPC-IF which registers either SPI or
HyperFLash device depending on the contents of the device tree subnode.
It also provides the absract "back end" device APIs that can be used by
the "front end" SPI/MTD drivers to talk to the real hardware.

Based on the original patch by Mason Yang <masonccyang@mxic.com.tw>.
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Link: https://lore.kernel.org/r/9a3606ec-d4d0-c63a-4fb6-631ab38e621c@cogentembedded.comSigned-off-by: Mark Brown <broonie@kernel.org>

Renesas Reduced Pin Count Interface (RPC-IF) allows a SPI flash or
HyperFlash connected to the SoC to be accessed via the external address
space read mode or the manual mode.

Document the device tree bindings for the Renesas RPC-IF found in the R-Car
gen3 SoCs.

Based on the original patch by Mason Yang <masonccyang@mxic.com.tw>.
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Link: https://lore.kernel.org/r/54a84c75-fa17-9976-d9a6-a69ef67c418b@cogentembedded.comSigned-off-by: Mark Brown <broonie@kernel.org>

The blind and counted loops are always called with nonzero count, so
convert them to do-while loops that lead to slightly more efficient
code generation. With GCC 8.3 this shaves off 1-2 instructions per
iteration in each case.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/9242863077acf9a64e4b3720e479855b88d19e82.1592261248.git.robin.murphy@arm.comSigned-off-by: Mark Brown <broonie@kernel.org>

The IRQ handler only needs the struct spi_controller for the sake of
the completion at the end of a transfer. Passing the struct bcm2835_spi
directly as the IRQ data allows that level of indirection to be pushed
into the completion path for the reverse lookup, and avoided entirely
in all other cases.

This saves one explicit load in the critical path, plus (for a GCC 8.3
build) two registers worth of stack frame overhead.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/6b401cb521539caffab21f05b4c8cba6c9d27c6e.1592261248.git.robin.murphy@arm.comSigned-off-by: Mark Brown <broonie@kernel.org>

It doesn't need a struct spi_controller, and every callsite has
already retrieved the appropriate struct bcm2835_spi, so just pass
that directly.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/eca458ae1a0d3934d0627f90e25d294fefd4b13d.1592261248.git.robin.murphy@arm.comSigned-off-by: Mark Brown <broonie@kernel.org>

The OMAP2 MCSPI has some kind of half-baked GPIO CS support:
it includes code like this:

  if (gpio_is_valid(spi->cs_gpio)) {
        ret = gpio_request(spi->cs_gpio, dev_name(&spi->dev));
	(...)

But it doesn't parse the "cs-gpios" attribute in the device
tree to count the number of GPIOs or pick out the GPIO numbers
and put these in the SPI master's .cs_gpios property.

We complete the implementation of supporting CS GPIOs
from the device tree and switch it over to use the SPI core
for this.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20200625231257.280615-1-linus.walleij@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>

Setting the chip select on the Qualcomm geni SPI controller isn't
exactly cheap.  Let's cache the current setting and avoid setting the
chip select if it's already right.

Using "flashrom" to read or write the EC firmware on a Chromebook
shows roughly a 25% reduction in interrupts and a 15% speedup.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200626151946.1.I06134fd669bf91fd387dc6ecfe21d44c202bd412@changeidSigned-off-by: Mark Brown <broonie@kernel.org>

Add the MODULE_DEVICE_TABLE macro for the platform_device_id table to
allow proper creation of modalias strings and fix autoloading module for
this driver.
Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Signed-off-by: Russ Weight <russell.h.weight@intel.com>
Link: https://lore.kernel.org/r/1592962286-25752-3-git-send-email-yilun.xu@intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

The driver is expected to support device ID "spi_altera" for MMIO accessed
devices, device ID "subdev_spi_altera" for indirect accessed devices. But
the platform bus will not try driver name match anymore if the platform
driver has an id_table. So the "spi_altera" should also be added to
id_table.
Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Signed-off-by: Russ Weight <russell.h.weight@intel.com>
Link: https://lore.kernel.org/r/1592962286-25752-2-git-send-email-yilun.xu@intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

Add fallback pio feature in case  dma transfer failed before start.
Besides, another whole pio transfer including setup_transfer will be
issued by spi core, no need to restore jobs like commit bcd8e776 ("spi:
imx: fallback to PIO if dma setup failure").
Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Link: https://lore.kernel.org/r/1592347329-28363-3-git-send-email-yibin.gong@nxp.comSigned-off-by: Mark Brown <broonie@kernel.org>

Add fallback to pio mode in case dma transfer failed with error status
SPI_TRANS_FAIL_NO_START.
If spi client driver want to enable this feature please set xfer->error in
the proper place such as dmaengine_prep_slave_sg() failure detect(but no
any data put into spi bus yet). Besides, add master->fallback checking in
its can_dma() so that spi core could switch to pio next time. Please refer
to spi-imx.c.
Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Link: https://lore.kernel.org/r/1592347329-28363-2-git-send-email-yibin.gong@nxp.comSigned-off-by: Mark Brown <broonie@kernel.org>

To follow onto Doug's latest spi geni series[1] this simplifies and
reduces the code a little more.

[1] https://lore.kernel.org/r/20200618150626.237027-1-dianders@chromium.org

Stephen Boyd (2):
  spi: spi-geni-qcom: Simplify setup_fifo_xfer()
  spi: spi-geni-qcom: Don't set {tx,rx}_rem_bytes unnecessarily

 drivers/spi/spi-geni-qcom.c | 55 +++++++++++++++++--------------------
 1 file changed, 25 insertions(+), 30 deletions(-)

base-commit: 7ba9bdcb
--
Sent by a computer, using git, on the internet

We only need to test for these counters being non-zero when we see the
end of a transfer. If we're doing a CS change then they will already be
zero.  This implies that we don't need to set these to 0 if we're
cancelling an in flight transfer too, because we only care to test these
counters when the 'DONE' bit is set in the hardware and we've set them
to non-zero for a transfer.

This is a non-functional change, just cleanup to consolidate code.
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200620022233.64716-3-swboyd@chromium.orgSigned-off-by: Mark Brown <broonie@kernel.org>

The definition of SPI_FULL_DUPLEX (3) is really SPI_TX_ONLY (1) ORed
with SPI_RX_ONLY (2). Let's drop the define and simplify the code here a
bit by collapsing the setting of 'm_cmd' into conditions that are the
same.

This is a non-functional change, just cleanup to consolidate code.
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200620022233.64716-2-swboyd@chromium.orgSigned-off-by: Mark Brown <broonie@kernel.org>

The definition of SPI_FULL_DUPLEX (3) is really SPI_TX_ONLY (1) ORed
with SPI_RX_ONLY (2). Let's drop the define and simplify the code here a
bit by collapsing the setting of 'm_cmd' into conditions that are the
same.

This is a non-functional change, just cleanup to consolidate code.
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Cc: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200618233959.160032-1-swboyd@chromium.orgSigned-off-by: Mark Brown <broonie@kernel.org>

Merge series "mtd: spi-nor: Move cadence-qaudspi to spi-mem framework" from Vignesh Raghavendra <vigneshr@ti.com>:

This series is a subset of "[PATCH v12 0/4] spi: cadence-quadspi: Add
support for the Cadence QSPI controller" by Ramuthevar,Vadivel MuruganX
<vadivel.muruganx.ramuthevar@linux.intel.com> that intended to move
cadence-quadspi driver to spi-mem framework

Those patches were trying to accomplish too many things in a single set
of patches and need to split into smaller patches. This is reduced
version of above series.

Changes that are intended to make migration easy are split into separate
patches. Patches 1 to 3 drop features that cannot be supported under
spi-mem at the moment (backward compatibility is maintained).
Patch 4-5 are trivial cleanups. Patch 6 does the actual conversion to
spi-mem and patch 7 moves the driver to drivers/spi folder.

I have tested both INDAC mode (used by non TI platforms like Altera
SoCFPGA) and DAC mode (used by TI platforms) on TI EVMs.

Patches to move move bindings over to
"Documentation/devicetree/bindings/spi/" directory and also conversion
of bindig doc to YAML will be posted separately.  Support for Intel
platform would follow that.

Resend v3:
Rebased onto v5.7-c1

v3:
Split handling of probe deferral into separate patch (out of 5/6)
Split dropping of redundant WREN to separate patch (out of 5/6)
Fix a possible memleak due to lack of spi_master_put()
Parse all SPI slave nodes in cqspi_setup_flash()
Address misc comments from Tudor on v2
Rebase onto latest spi-nor/next

v2:
Rework patch 1/6 to keep "cdns,is-decoded-cs" property supported.

Ramuthevar Vadivel Murugan (2):
  mtd: spi-nor: Convert cadence-quadspi to use spi-mem framework
  spi: Move cadence-quadspi driver to drivers/spi/

Vignesh Raghavendra (6):
  mtd: spi-nor: cadence-quadspi: Make driver independent of flash
    geometry
  mtd: spi-nor: cadence-quadspi: Provide a way to disable DAC mode
  mtd: spi-nor: cadence-quadspi: Don't initialize rx_dma_complete on
    failure
  mtd: spi-nor: cadence-quadspi: Fix error path on failure to acquire
    reset lines
  mtd: spi-nor: cadence-quadspi: Handle probe deferral while requesting
    DMA channel
  mtd: spi-nor: cadence-quadspi: Drop redundant WREN in erase path

 drivers/mtd/spi-nor/controllers/Kconfig       |  11 -
 drivers/mtd/spi-nor/controllers/Makefile      |   1 -
 drivers/spi/Kconfig                           |  11 +
 drivers/spi/Makefile                          |   1 +
 .../spi-cadence-quadspi.c}                    | 541 +++++++-----------
 5 files changed, 222 insertions(+), 343 deletions(-)
 rename drivers/{mtd/spi-nor/controllers/cadence-quadspi.c => spi/spi-cadence-quadspi.c} (74%)

base-commit: b3a9e3b9

--
2.26.2

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Now that cadence-quadspi has been converted to use spi-mem framework,
move it under drivers/spi/

Update license header to match SPI subsystem style
Signed-off-by: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@linux.intel.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20200601070444.16923-9-vigneshr@ti.comSigned-off-by: Mark Brown <broonie@kernel.org>

Move cadence-quadspi driver to use spi-mem framework. This is required
to make the driver support for SPI NAND flashes in future.

Driver is feature compliant with existing SPI NOR version.
Signed-off-by: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@linux.intel.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20200601070444.16923-8-vigneshr@ti.comSigned-off-by: Mark Brown <broonie@kernel.org>

Drop redundant WREN command in cqspi_erase() as SPI NOR core takes care
of sending WREN command before sending erase command.
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20200601070444.16923-7-vigneshr@ti.comSigned-off-by: Mark Brown <broonie@kernel.org>

dma_request_chan_by_mask() can throw EPROBE_DEFER if DMA provider
is not yet probed. Currently driver just falls back to using PIO mode
(which is less efficient) in this case. Instead return probe deferral
error as is so that driver will be re probed once DMA provider is
available.
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20200601070444.16923-6-vigneshr@ti.comSigned-off-by: Mark Brown <broonie@kernel.org>

Make sure to undo the prior changes done by the driver when exiting due
to failure to acquire reset lines.
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20200601070444.16923-5-vigneshr@ti.comSigned-off-by: Mark Brown <broonie@kernel.org>

If driver fails to acquire DMA channel then don't initialize
rx_dma_complete struct as it won't be used.
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20200601070444.16923-4-vigneshr@ti.comSigned-off-by: Mark Brown <broonie@kernel.org>

Currently direct access mode is used on platforms that have AHB window
(memory mapped window) larger than flash size. This feature is limited
to TI platforms as non TI platforms have < 1MB of AHB window.
Therefore introduce a driver quirk to disable DAC mode and set it for
non TI compatibles. This is in preparation to move to spi-mem framework
where flash geometry cannot be known.
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20200601070444.16923-3-vigneshr@ti.comSigned-off-by: Mark Brown <broonie@kernel.org>

Drop configuration of Flash size, erase size and page size
configuration. Flash size is needed only if using AHB decoder (BIT 23 of
CONFIG_REG) which is not used by the driver.
Erase size and page size are needed if IP is configured to send WREN
automatically. But since SPI NOR layer takes care of sending WREN, there
is no need to configure these fields either.

Therefore drop these in preparation to move the driver to spi-mem
framework where flash geometry is not visible to controller driver.
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20200601070444.16923-2-vigneshr@ti.comSigned-off-by: Mark Brown <broonie@kernel.org>

Updated the regmap & indirect access support for spi-altera.

Patch #1 is an 1:1 replacement of of readl/writel with regmap_read/write
Patch #2 introduced a new platform_device_id to support indirect access as
         a sub device.
Patch #3 is a minor fix.

Main changes from v1:
 - Split the regmap supporting patch to 2 patches.
 - Add a new platform_device_id to support indirect access.
 - Removed the v1 patch "move driver name string to header file". Now we
   use driver name string directly.
 - Add Yilun's Signed-off-by for Patch #3.
 - Add Tom's Reviewed-by.

Matthew Gerlach (1):
  spi: altera: fix size mismatch on 64 bit processors

Xu Yilun (2):
  spi: altera: use regmap-mmio instead of direct mmio register access
  spi: altera: support indirect access to the registers

 drivers/spi/Kconfig      |   1 +
 drivers/spi/spi-altera.c | 127 +++++++++++++++++++++++++++++++++++++++--------
 2 files changed, 107 insertions(+), 21 deletions(-)

--
2.7.4

Merge series "spi: spi-geni-qcom: Fixes / perf improvements" from Douglas Anderson <dianders@chromium.org>:

This patch series is a new version of the previous patch posted:
  [PATCH v2] spi: spi-geni-qcom: Speculative fix of "nobody cared" about interrupt
  https://lore.kernel.org/r/20200317133653.v2.1.I752ebdcfd5e8bf0de06d66e767b8974932b3620e@changeid

At this point I've done enough tracing to know that there was a real
race in the old code (not just weakly ordered memory problems) and
that should be fixed with the locking patches.

While looking at this driver, I also noticed we weren't properly
noting error interrupts and also weren't actually using our FIFO
effectively, so I fixed those.

The last patch in the series addresses review feedback about dislike
for the "cur_mcmd" state variable.  It also could possibly make
"abort" work ever-so-slightly more reliably.

Changes in v4:
- Drop 'controller' in comment.
- Use Stephen's diagram to explain the race better.

Changes in v3:
- ("spi: spi-geni-qcom: No need for irqsave variant...") new for v3
- Split out some lock cleanup to previous patch.
- Don't need to read IRQ status register inside spinlock.
- Don't check for state CMD_NONE; later patch is removing state var.
- Don't hold the lock for all of setup_fifo_xfer().
- Comment about why it's safe to Ack interrupts at the end.
- Subject/desc changed since race is definitely there.
- ("spi: spi-geni-qcom: Check for error IRQs") new in v3.
- ("spi: spi-geni-qcom: Actually use our FIFO") new in v3.
- ("spi: spi-geni-qcom: Don't keep a local state variable") new in v3.

Changes in v2:
- Detect true spurious interrupt.
- Still return IRQ_NONE for state machine mismatch, but print warn.

Douglas Anderson (5):
  spi: spi-geni-qcom: No need for irqsave variant of spinlock calls
  spi: spi-geni-qcom: Mo' betta locking
  spi: spi-geni-qcom: Check for error IRQs
  spi: spi-geni-qcom: Actually use our FIFO
  spi: spi-geni-qcom: Don't keep a local state variable

 drivers/spi/spi-geni-qcom.c | 120 ++++++++++++++++++++++++------------
 1 file changed, 81 insertions(+), 39 deletions(-)

--
2.27.0.290.gba653c62da-goog

No need to redefine already existing definition.
So, replace custom by generic one.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200618170144.57433-1-andriy.shevchenko@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

The variable "cur_mcmd" kept track of our current state (idle, xfer,
cs, cancel).  We don't really need it, so get rid of it.  Instead:
* Use separate condition variables for "chip select done", "cancel
  done", and "abort done".  This is important so that if a "done"
  comes through (perhaps some previous interrupt finally came through)
  it can't confuse the cancel/abort function.
* Use the "done" interrupt only for when a chip select or transfer is
  done and we can tell the difference by looking at whether "cur_xfer"
  is NULL.

This is mostly a no-op change.  However, it is possible it could fix
an issue where a super delayed interrupt for a cancel command could
have confused our waiting for an abort command.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20200618080459.v4.5.Ib1e6855405fc9c99916ab7c7dee84d73a8bf3d68@changeidSigned-off-by: Mark Brown <broonie@kernel.org>

The geni hardware has a FIFO that can hold up to 64 bytes (it has 16
entries that can hold 4 bytes each), at least on the two SoCs I tested
(sdm845 and sc7180).  We configured our RX Watermark to 0, which
basically meant we got an interrupt as soon as the first 4 bytes
showed up in the FIFO.  Tracing the IRQ handler showed that we often
only read 4 or 8 bytes per IRQ handler.

I tried setting the RX Watermark to "fifo size - 2" but that just got
me a bunch of overrun errors reported.  Setting it to "fifo size - 3"
seemed to work great, though.  This made me worried that we'd start
getting overruns if we had long interrupt latency, but that doesn't
appear to be the case and delays inserted in the IRQ handler while
using "fifo size - 3" didn't cause any errors.  Presumably there is
some interaction with the poorly-documented RFR (ready for receive)
level means that "fifo size - 3" is the max.  We are the SPI master,
so it makes sense that there would be no problems with overruns, the
master should just stop clocking.

Despite "fifo size - 3" working, I chose "fifo size / 2" (8 entries =
32 bytes) which gives us a little extra time to get to the interrupt
handler and should reduce dead time on the SPI wires.  With this
setting, I often saw the IRQ handler handle 40 bytes but sometimes up
to 56 if we had bad interrupt latency.

Testing by running "flashrom -p ec -r" on a Chromebook saw interrupts
from the SPI driver cut roughly in half.  Time was roughly the same.

Fixes: 561de45f ("spi: spi-geni-qcom: Add SPI driver support for GENI based QUP")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20200618080459.v4.4.I988281f7c6ee0ed00325559bfce7539f403da69e@changeidSigned-off-by: Mark Brown <broonie@kernel.org>

>From reading the #defines it seems like we should shout if we ever see
one of these error bits.  Let's do so.  This doesn't do anything
functional except print a yell in the log if the error bits are seen.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20200618080459.v4.3.Id8bebdbdb4d2ed9468634343a7e6207d6cffff8a@changeidSigned-off-by: Mark Brown <broonie@kernel.org>

If you added a bit of a delay (like a trace_printk) into the ISR for
the spi-geni-qcom driver, you would suddenly start seeing some errors
spit out.  The problem was that, though the ISR itself held a lock,
other parts of the driver didn't always grab the lock.

One example race was this:
  CPU0                                         CPU1
  ----                                         ----
  spi_geni_set_cs()
   mas->cur_mcmd = CMD_CS;
   geni_se_setup_m_cmd(...)
   wait_for_completion_timeout(&xfer_done);
                                              <INTERRUPT>
                                               geni_spi_isr()
                                                complete(&xfer_done);
   <wakeup>
   pm_runtime_put(mas->dev);
  ... // back to SPI core
  spi_geni_transfer_one()
   setup_fifo_xfer()
    mas->cur_mcmd = CMD_XFER;
                                                mas->cur_cmd = CMD_NONE; // bad!
                                                return IRQ_HANDLED;

Let's fix this.  Before we start messing with hardware, we'll grab the
lock to make sure that the IRQ handler from some previous command has
really finished.  We don't need to hold the lock unless we're in a
state where more interrupts can come in, but we at least need to make
sure the previous IRQ is done.  This lock is used exclusively to
prevent the IRQ handler and non-IRQ from stomping on each other.  The
SPI core handles all other mutual exclusion.

As part of this, we change the way that the IRQ handler detects
spurious interrupts.  Previously we checked for our state variable
being set to IRQ_NONE, but that was done outside the spinlock.  We
could move it into the spinlock, but instead let's just change it to
look for the lack of any IRQ status bits being set.  This can be done
outside the lock--the hardware certainly isn't grabbing or looking at
the spinlock when it updates its status register.

It's possible that this will fix real (but very rare) errors seen in
the field that look like:
  irq ...: nobody cared (try booting with the "irqpoll" option)

NOTE: an alternate strategy considered here was to always make the
complete() / spi_finalize_current_transfer() the very last thing in
our IRQ handler.  With such a change you could consider that we could
be "lockless".  In that case, though, we'd have to be very careful w/
memory barriers so we made sure we didn't have any bugs with weakly
ordered memory.  Using spinlocks makes the driver much easier to
understand.

Fixes: 561de45f ("spi: spi-geni-qcom: Add SPI driver support for GENI based QUP")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20200618080459.v4.2.I752ebdcfd5e8bf0de06d66e767b8974932b3620e@changeidSigned-off-by: Mark Brown <broonie@kernel.org>

The spi-altera driver was originally written with a 32
bit processor, where sizeof(unsigned long) is 4.  On a
64 bit processor sizeof(unsigned long) is 8.  Change the structure
member to u32 to match the actual size of the control
register.
Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Reviewed-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/1592531021-11412-4-git-send-email-yilun.xu@intel.comSigned-off-by: Mark Brown <broonie@kernel.org>