gcc complains, rightfully so, I think:

drivers/i2c/busses/i2c-ocores.c:32: warning: Cannot understand  * @process_lock: protect I2C transfer process.
 on line 32 - I thought it was a doc line

Make it a simple comment.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

On most Intel Bay- and Cherry-Trail systems the PMIC is connected over I2C
and the PMIC is accessed through various means by the _PS0 and _PS3 ACPI
methods (power on / off methods) of various devices.

This leads to suspend/resume ordering problems where a device may be
resumed and get its _PS0 method executed before the I2C controller is
resumed. On Cherry Trail this leads to errors like these:

     i2c_designware 808622C1:06: controller timed out
     ACPI Error: AE_ERROR, Returned by Handler for [UserDefinedRegion]
     ACPI Error: Method parse/execution failed \_SB.P18W._ON, AE_ERROR
     video LNXVIDEO:00: Failed to change power state to D0

But on Bay Trail this caused I2C reads to seem to succeed, but they end
up returning wrong data, which ends up getting written back by the typical
read-modify-write cycle done to turn on various power-resources.

Debugging the problems caused by this silent data corruption is quite
nasty. This commit adds a check which disallows i2c_dw_xfer() calls to
happen until the controller's resume method has completed.

Which turns the silent data corruption into getting these errors in
dmesg instead:

    i2c_designware 80860F41:04: Error i2c_dw_xfer call while suspended
    ACPI Error: AE_ERROR, Returned by Handler for [UserDefinedRegion]
    ACPI Error: Method parse/execution failed \_SB.PCI0.GFX0._PS0, AE_ERROR

Which is much better.

Note the above errors are an example of issues which this patch will
help to debug, the actual fix requires fixing the suspend order and
this has been fixed by a different commit.

Note the setting / clearing of the suspended flag in the suspend / resume
methods is NOT protected by i2c_lock_bus(). This is intentional as these
methods get called from i2c_dw_xfer() (through pm_runtime_get/put) a nd
i2c_dw_xfer() is called with the i2c_bus_lock held, so otherwise we would
deadlock. This means that there is a theoretical race between a non runtime
suspend and the suspended check in i2c_dw_xfer(), this is not a problem
since normally we should not hit the race and this check is primarily a
debugging tool so hitting the check if there are suspend/resume ordering
problems does not need to be 100% reliable.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Commit 86c92b99 ("i2c: tegra: Add DMA support") added DMA support
to the Tegra I2C driver for Tegra devices that support the APB DMA
controller. One side-effect of this change is that even for Tegra
devices that do not have an APB DMA controller and hence, cannot
support DMA tranfers for I2C transactions, the following error messages
are still displayed ...

 ERR KERN tegra-i2c 31c0000.i2c: cannot use DMA: -19
 ERR KERN tegra-i2c 31c0000.i2c: falling back to PIO

There is no point displaying the above messages for devices that do not
have an APB DMA controller and so fix this by returning from the
tegra_i2c_init_dma() function if 'has_apb_dma' is not true.

Furthermore, if CONFIG_TEGRA20_APB_DMA is not set, then rather than
printing an error message, print an debug message as for whatever reason
this could be intentional.

Fixes: 86c92b99 ("i2c: tegra: Add DMA support")
Signed-off-by: NJonathan Hunter <jonathanh@nvidia.com>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Acked-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Add a fault injector simulating a Kernel panic happening after starting
a transfer. Read the docs for its usage.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Add a fault injector simulating 'arbitration lost' from multi-master
setups. Read the docs for its usage.

A helper function for future fault injectors using SCL interrupts is
created to achieve this.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Multi-master support is defeatured on Tegra210 and Tegra186 due to
known bugs.

This patch removes multi-master support for Tegra210 and Tegra186
I2C HW feature.
Acked-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Tegra186 does not have master FIFO  control register and instead
uses FIFO control register like prior Tegra chipset.

This patch fixes this and prevents crashing during boot when
accessing FIFO control registers.
Acked-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The phrasing in two dev_err messages is using fallbacking which
os less understandable than "falling back", so fix this up.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Actually, total amount of available minor number for a single major is
MINORMASK + 1. So expand minor range when registering chrdev region.
Signed-off-by: NChengguang Xu <cgxu519@gmx.com>
[wsa: fixed typo in commit message]
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

In multi-master environment, this driver's master cannot know
exactly when a peer master sends data to this driver's slave so
cases can be happened that this master tries sending data through
the master_xfer function but slave data from a peer master is still
being processed or slave xfer is started by a peer immediately
after it queues a master command. To support multi-master use cases
properly, this H/W provides arbitration in physical level and it
provides priority based command handling too to avoid conflicts in
multi-master environment, means that if a master and a slave events
happen at the same time, H/W will handle a higher priority event
first and a pending event will be handled when bus comes back to
the idle state.

To support this H/W feature properly, this patch adds the 'pending'
state of master and its handling code so that the pending master
xfer can be continued after slave operation properly.
Signed-off-by: NJae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
Reviewed-by: NBrendan Higgins <brendanhiggins@google.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Merge tag 'at24-5.1-updates-for-wolfram' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux into i2c/for-5.1

at24 updates for v5.1

- finally remove legacy platform data as all users have been switched
  to using device properties and nvmem notifier chain
- add support for the 'num-addresses' property

If an smbus transfer fails, there's no guarantee that the output
buffer was written.  So, avoid trying to show the output buffer when
tracing after an error.  This was 'mostly harmless', but would trip
up kasan checking if left-over cruft in byte 0 is a large length,
causing us to read from unwritten memory.
Signed-off-by: NJohn Sperbeck <jsperbeck@google.com>
Reviewed-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Add the I2C bus clock speed to the platform data structure.
If not set, default to 100KHz as before.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Some implementations of the OCORES i2c bus master use IO mapped
registers. Add support for getting the IO registers from the platform
data, and register accessor functions.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Miscellaneous style fixes from checkpatch
Signed-off-by: NFederico Vaga <federico.vaga@cern.ch>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

It adds the SPDX tag and it removes the old text about the GPLv2.
Signed-off-by: NFederico Vaga <federico.vaga@cern.ch>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This driver assumes that an interrupt line is always available for
the I2C master. This is not always the case and this patch adds support
for a polling version.

Report from Andrew Lunn:

  I did some timing tests for this. On my box, we request a udelay of
  80uS. The kernel actually delays for about 79uS. We then spin in
  ocores_wait() for an additional 10-11uS, which is 3 to 4 iterations.

  There are actually 9 bits on the wire, not 8, since there is an
  ACK/NACK bit after the actual data transfer. So i changed the delay to
  (9 * 1000) / i2c->bus_clock_khz. That resulted in ocores_wait() mostly
  not looping at all. But for reading an 4K AT24 EEPROM, it increased
  the read time by 10ms, from 424ms to 434ms. So we should probably keep
  with 8.
Signed-off-by: NFederico Vaga <federico.vaga@cern.ch>
Tested-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

If the Interrupt Flag (IF) is not set, we should not handle the IRQ:
- the line can be shared with other devices
- it can be a spurious interrupt

To avoid reading twice the status register, the ocores_process() function
expects it to be read by the caller.
Signed-off-by: NFederico Vaga <federico.vaga@cern.ch>
Acked-by: NPeter Korsgaard <peter@korsgaard.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Detecting a timeout is ok, but we also need to assert a STOP command on
the bus in order to prevent it from generating interrupts when there are
no on going transfers.

Example: very long transmission.

1. ocores_xfer: START a transfer
2. ocores_isr : handle byte by byte the transfer
3. ocores_xfer: goes in timeout [[bugfix here]]
4. ocores_xfer: return to I2C subsystem and to the I2C driver
5. I2C driver : it may clean up the i2c_msg memory
6. ocores_isr : receives another interrupt (pending bytes to be
                transferred) but the i2c_msg memory is invalid now

So, since the transfer was too long, we have to detect the timeout and
STOP the transfer.

Another point is that we have a critical region here. When handling the
timeout condition we may have a running IRQ handler. For this reason I
introduce a spinlock.

In order to make easier to understan locking I have:
- added a new function to handle timeout
- modified the current ocores_process() function in order to be protected
  by the new spinlock
Like this it is obvious at first sight that this locking serializes
the execution of ocores_process() and ocores_process_timeout()
Signed-off-by: NFederico Vaga <federico.vaga@cern.ch>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This patch adds I2C interface timing registers support for
proper bus rate configuration along with meeting the I2C spec
setup and hold times based on the tuning performed on Tegra210,
Tegra186 and Tegra194 platforms.

I2C_INTERFACE_TIMING_0 register contains TLOW and THIGH field
and Tegra I2C controller design uses them as a part of internal
clock divisor.

I2C_INTERFACE_TIMING_1 register contains the setup and hold times
for start and stop conditions.
Acked-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Tested-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Tegra194 allows max of 64K bytes and Tegra186 and prior allows
max of 4K bytes of transfer per packet.

one sec timeout is not enough for transfers more than 10K bytes
at STD bus rate.

This patch updates I2C transfer timeout based on the transfer size
and I2C bus rate to allow enough time during max transfer size at
lower bus speed.
Acked-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This patch adds DMA support for Tegra I2C.

Tegra I2C TX and RX FIFO depth is 8 words. PIO mode is used for
transfer size of the max FIFO depth and DMA mode is used for
transfer size higher than max FIFO depth to save CPU overhead.

PIO mode needs full intervention of CPU to fill or empty FIFO's
and also need to service multiple data requests interrupt for the
same transaction. This adds delay between data bytes of the same
transfer when CPU is fully loaded and some slave devices has
internal timeout for no bus activity and stops transaction to
avoid bus hang. DMA mode is helpful in such cases.

DMA mode is also helpful for Large transfers during downloading or
uploading FW over I2C to some external devices.

Tegra210 and prior Tegra chips use APBDMA driver which is replaced
with GPCDMA on Tegra186 and Tegra194.
This patch uses has_apb_dma flag in hw_feature to differentiate
DMA driver change between Tegra chipset.

APBDMA driver is registered from module-init level and this patch
also has a change to register I2C driver at module-init level
rather than subsys-init to avoid deferring I2C probe till APBDMA
driver is registered.
Acked-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Tested-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Tegra194 supports maximum 64K bytes per packet including 12 bytes of
packet header irrespective of PIO or DMA mode transfer.

This patch updates Tegra194 max write length to account for packet
header size for transfers.

Cc: stable@vger.kernel.org # 4.20+
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Tegra186 and prior supports maximum 4K bytes per packet transfer
including 12 bytes of packet header.

This patch fixes max write length limit to account packet header
size for transfers.

Cc: stable@vger.kernel.org # 4.4+
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Bus clear feature of Tegra I2C controller helps to recover from
bus hang when I2C master loses the bus arbitration due to the
slave device holding SDA LOW continuously for some unknown reasons.

Per I2C specification, the device that held the bus LOW should
release it within 9 clock pulses.

During bus clear operation, Tegra I2C controller sends 9 clock
pulses and terminates the transaction with STOP condition.
Upon successful bus clear operation, bus goes to idle state and
driver retries the transaction.
Acked-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This patch sorts all the include headers alphabetically for the
I2C Tegra driver.
Acked-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

If the device node defines 'num-addresses', let it override the default
behavior.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>

Currently the at24 driver only creates additional i2c dummies for
atmel,24c00 and it's hard-coded. Some other chips (like for example
Microchip's 24AA02T) also take more slave addresses despite being
otherwise compatible with already supported variants.

Add a new property to the device tree binding document that defines
the total number of i2c slave addresses taken by the device. The
addresses are counted starting from the one in the reg property.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>

There are no more users of at24_platform_data. Remove the relevant
header and modify the driver code to not use it anymore.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>

Merge branch 'v5.1/eeprom-for-bartosz' of git://git.kernel.org/pub/scm/linux/kernel/git/nsekhar/linux-davinci into at24/for-next

Pull dmaengine fixes from Vinod Koul:
 - Fix in at_xdmac fr wrongful channel state
 - Fix for imx driver for wrong callback invocation
 - Fix to bcm driver for interrupt race & transaction abort.
 - Fix in dmatest to abort in mapping error

* tag 'dmaengine-fix-5.0-rc6' of git://git.infradead.org/users/vkoul/slave-dma:
  dmaengine: dmatest: Abort test in case of mapping error
  dmaengine: bcm2835: Fix abort of transactions
  dmaengine: bcm2835: Fix interrupt race on RT
  dmaengine: imx-dma: fix wrong callback invoke
  dmaengine: at_xdmac: Fix wrongfull report of a channel as in use

Pull x86 fixes from Ingo Molnar:
 "A handful of fixes:

   - Fix an MCE corner case bug/crash found via MCE injection testing

   - Fix 5-level paging boot crash

   - Fix MCE recovery cache invalidation bug

   - Fix regression on Xen guests caused by a recent PMD level mremap
     speedup optimization"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Make set_pmd_at() paravirt aware
  x86/mm/cpa: Fix set_mce_nospec()
  x86/boot/compressed/64: Do not corrupt EDX on EFER.LME=1 setting
  x86/MCE: Initialize mce.bank in the case of a fatal error in mce_no_way_out()

Pull irq fixes from Ingo Molnar:
 "irqchip driver fixes: most of them are race fixes for ARM GIC (General
  Interrupt Controller) variants, but also a fix for the ARM MMP
  (Marvell PXA168 et al) irqchip affecting OLPC keyboards"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/gic-v3-its: Fix ITT_entry_size accessor
  irqchip/mmp: Only touch the PJ4 IRQ & FIQ bits on enable/disable
  irqchip/gic-v3-its: Gracefully fail on LPI exhaustion
  irqchip/gic-v3-its: Plug allocation race for devices sharing a DevID
  irqchip/gic-v4: Fix occasional VLPI drop

Pull perf fixes from Ingo Molnar:
 "A couple of kernel side fixes:

   - Fix the Intel uncore driver on certain hardware configurations

   - Fix a CPU hotplug related memory allocation bug

   - Remove a spurious WARN()

  ... plus also a handful of perf tooling fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf script python: Add Python3 support to tests/attr.py
  perf trace: Support multiple "vfs_getname" probes
  perf symbols: Filter out hidden symbols from labels
  perf symbols: Add fallback definitions for GELF_ST_VISIBILITY()
  tools headers uapi: Sync linux/in.h copy from the kernel sources
  perf clang: Do not use 'return std::move(something)'
  perf mem/c2c: Fix perf_mem_events to support powerpc
  perf tests evsel-tp-sched: Fix bitwise operator
  perf/core: Don't WARN() for impossible ring-buffer sizes
  perf/x86/intel: Delay memory deallocation until x86_pmu_dead_cpu()
  perf/x86/intel/uncore: Add Node ID mask

Pull locking fixes from Ingo Molnar:
 "An rtmutex (PI-futex) deadlock scenario fix, plus a locking
  documentation fix"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Handle early deadlock return correctly
  futex: Fix barrier comment

set_pmd_at() calls native_set_pmd() unconditionally on x86. This was
fine as long as only huge page entries were written via set_pmd_at(),
as Xen pv guests don't support those.

Commit 2c91bd4a ("mm: speed up mremap by 20x on large regions")
introduced a usage of set_pmd_at() possible on pv guests, leading to
failures like:

BUG: unable to handle kernel paging request at ffff888023e26778
#PF error: [PROT] [WRITE]
RIP: e030:move_page_tables+0x7c1/0xae0
move_vma.isra.3+0xd1/0x2d0
__se_sys_mremap+0x3c6/0x5b0
 do_syscall_64+0x49/0x100
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Make set_pmd_at() paravirt aware by just letting it use set_pmd().

Fixes: 2c91bd4a ("mm: speed up mremap by 20x on large regions")
Reported-by: NSander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: xen-devel@lists.xenproject.org
Cc: boris.ostrovsky@oracle.com
Cc: sstabellini@kernel.org
Cc: hpa@zytor.com
Cc: bp@alien8.de
Cc: torvalds@linux-foundation.org
Link: https://lkml.kernel.org/r/20190210074056.11842-1-jgross@suse.com

Pull i2c fixes from Wolfram Sang:
 "One PM related driver bugfix and a MAINTAINERS update"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  MAINTAINERS: Update the ocores i2c bus driver maintainer, etc
  i2c: omap: Use noirq system sleep pm ops to idle device for suspend

Pull MIPS fixes from Paul Burton:
 "A batch of MIPS fixes for 5.0, nothing too scary.

   - A workaround for a Loongson 3 CPU bug is the biggest change, but
     still fairly straightforward. It adds extra memory barriers (sync
     instructions) around atomics to avoid a CPU bug that can break
     atomicity.

   - Loongson64 also sees a fix for powering off some systems which
     would incorrectly reboot rather than waiting for the power down
     sequence to complete.

   - We have DT fixes for the Ingenic JZ4740 SoC & the JZ4780-based Ci20
     board, and a DT warning fix for the Nexsys4/MIPSfpga board.

   - The Cavium Octeon platform sees a further fix to the behaviour of
     the pcie_disable command line argument that was introduced in v3.3.

   - The VDSO, introduced in v4.4, sees build fixes for configurations
     of GCC that were built using the --with-fp-32= flag to specify a
     default 32-bit floating point ABI.

   - get_frame_info() sees a fix for configurations with
     CONFIG_KALLSYMS=n, for which it previously always returned an
     error.

   - If the MIPS Coherence Manager (CM) reports an error then we'll now
     clear that error correctly so that the GCR_ERROR_CAUSE register
     will be updated with information about any future errors"

* tag 'mips_fixes_5.0_3' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
  mips: cm: reprime error cause
  mips: loongson64: remove unreachable(), fix loongson_poweroff().
  MIPS: Remove function size check in get_frame_info()
  MIPS: Use lower case for addresses in nexys4ddr.dts
  MIPS: Loongson: Introduce and use loongson_llsc_mb()
  MIPS: VDSO: Include $(ccflags-vdso) in o32,n32 .lds builds
  MIPS: VDSO: Use same -m%-float cflag as the kernel proper
  MIPS: OCTEON: don't set octeon_dma_bar_type if PCI is disabled
  DTS: CI20: Fix bugs in ci20's device tree.
  MIPS: DTS: jz4740: Correct interrupt number of DMA core