Add an I2C bus driver for virtio para-virtualization.

The controller can be emulated by the backend driver in
any device model software by following the virtio protocol.

The device specification can be found on
https://lists.oasis-open.org/archives/virtio-comment/202101/msg00008.html.

By following the specification, people may implement different
backend drivers to emulate different controllers according to
their needs.
Co-developed-by: Conghui Chen <conghui.chen@intel.com>
Signed-off-by: Conghui Chen <conghui.chen@intel.com>
Signed-off-by: Jie Deng <jie.deng@intel.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Iff platform_get_irq() returns 0, the driver's probe() method will return 0
early (as if the method's call was successful).  Let's consider IRQ0 valid
for simplicity -- devm_request_irq() can always override that decision...

Fixes: 15ef2775 ("i2c: hix5hd2: add i2c controller driver")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Iff platform_get_irq() returns 0, the driver's probe() method will return 0
early (as if the method's call was successful).  Let's consider IRQ0 valid
for simplicity -- devm_request_irq() can always override that decision...

Fixes: e0d1ec97 ("i2c-s3c2410: Change IRQ to be plain integer.")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

When adding the code to handle platform_get_irq*() errors in the commit
48944738 ("handle errors returned by platform_get_irq*()"), the
actual error code was enforced to be -ENXIO in the driver for some
strange reason.  This didn't matter much until the deferred probing was
introduced -- which requires an actual error code to be propagated
upstream from the failure site.

While fixing this, also stop overriding the errors from request_irq() to
-EIO (done since the pre-git era).

Fixes: 48944738 ("[PATCH] handle errors returned by platform_get_irq*()")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

The driver overrides the error codes returned by platform_get_irq() to
-ENODEV, so if it returns -EPROBE_DEFER, the driver will fail the probe
permanently instead of the deferred probing. Switch to propagating the
error codes upstream.

Fixes: 0d676a6c ("i2c: add support for Socionext SynQuacer I2C controller")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omprussia.ru>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

strlcpy() reads the entire source buffer first. This read may exceed the
destination size limit. This is both inefficient and can lead to linear
read overflows if a source string is not NUL-terminated. The safe
replacement is strscpy().

This is a previous step in the path to remove the strlcpy() function
entirely from the kernel [1].

[1] https://github.com/KSPP/linux/issues/89Signed-off-by: Len Baker <len.baker@gmx.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Commit 1b00767f ("MIPS: Remove PMC MSP71xx platform") removes the
config PMC_MSP in ./arch/mips/Kconfig.

Hence, since then, the corresponding PMC MSP TWI/SMBus/I2C driver is
dead code. Remove this dead driver.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

The sysfs_emit() function was introduced to make it less ambiguous
which function is preferred when writing to the output buffer in
a "show" callback [1].

Convert the I²C device sysfs interface from sprintf() to sysfs_emit()
accordingly, as the latter is aware of the PAGE_SIZE buffer and correctly
returns the number of bytes written into the buffer.

No functional change intended.

[1] Documentation/filesystems/sysfs.rst
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Define pr_fmt() to print module name as prefix and at the same time
drop duplication substrings in the messages.

While at it, convert printk(<LEVEL>) to pr_<level>().
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

In couple of places the indentation makes harder to read the code.
Fix it to be sane.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Instead of open-coding DIV_ROUND_CLOSEST() and similar use the macros directly.
While at it, replace numbers with predefined SI metric prefixes.

No functional change intended.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Sometimes it's useful to have well-defined SI metric prefix to be used
to self-describe the formulas or equations.

List most popular ones in the units.h.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

The driver uses pm_ptr(), so the PM ops could be unused.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: dab4b0e8 ("i2c: at91: remove #define CONFIG_PM")
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Reviewed-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

dmaengine_terminate_all() is deprecated in favor of explicitly saying if
it should be sync or async. Here, we want dmaengine_terminate_sync()
because there is no other synchronization code in the driver to handle
an async case.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

dmaengine_terminate_all() is deprecated in favor of explicitly saying if
it should be sync or async. Here, we want dmaengine_terminate_sync()
because there is no other synchronization code in the driver to handle
an async case.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

dmaengine_terminate_all() is deprecated in favor of explicitly saying if
it should be sync or async. Here, we want dmaengine_terminate_sync()
because there is no other synchronization code in the driver to handle
an async case.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

dmaengine_terminate_all() is deprecated in favor of explicitly saying if
it should be sync or async. Here, we want dmaengine_terminate_sync()
because there is no other synchronization code in the driver to handle
an async case.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

dmaengine_terminate_all() is deprecated in favor of explicitly saying if
it should be sync or async. Here, we want dmaengine_terminate_sync()
because there is no other synchronization code in the driver to handle
an async case.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Remove #define CONFIG_PM and use __maybe_unused for PM functions and
pm_ptr() for PM ops.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Reviewed-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Switch to use module_parport_driver() to reduce boilerplate code.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

If a user is interested in such details he can enable smbus tracing.
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Tested-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

p2sb_spinlock is used in i801_add_tco_spt() only, and in process context
only. Therefore a mutex is sufficient, and we can make the definition
local to i801_add_tco_spt().
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Setting the autosuspend delay to a negative value disables runtime pm in
a little bit smarter way, because we need no cleanup when removing the
driver. Note that this is safe when reloading the driver, because the
call to pm_runtime_set_autosuspend_delay() in probe() will reverse the
effect. See update_autosuspend() for details.
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

The driver is written as if platform_get_irq() returns 0 on errors (while
actually it returns a negative error code), blithely passing these error
codes to request_irq() (which takes *unsigned* IRQ #) -- which fails with
-EINVAL. Add the necessary error check to the pre-existing *if* statement
forcing the driver into the polling mode...

Fixes: 4ad48e6a ("i2c: Renesas Highlander FPGA SMBus support")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Bit SMBHSTCNT_PEC_EN is used only if software calculates the CRC and
uses register SMBPEC. This is not supported by the driver, it supports
hw-calculation of CRC only (using bit SMBAUXSTS_CRCE). The chip spec
states the following, therefore never set bit SMBHSTCNT_PEC_EN.

Chapter SMBus CRC Generation and Checking
If the AAC bit is set in the Auxiliary Control register, the PCH
automatically calculates and drives CRC at the end of the transmitted
packet for write cycles, and will check the CRC for read cycles. It will
not transmit the contents of the PEC register for CRC. The PEC bit must
not be set in the Host Control register. If this bit is set, unspecified
behavior will result.

This patch is based solely on the specification and compile-tested only,
because I have no PEC-capable devices.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Tested-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

gcc doesn't care, but clang quite reasonably pointed out that the recent
commit e9ba16e6 ("smpboot: Mark idle_init() as __always_inlined to
work around aggressive compiler un-inlining") did some really odd
things:

    kernel/smpboot.c:50:20: warning: duplicate 'inline' declaration specifier [-Wduplicate-decl-specifier]
    static inline void __always_inline idle_init(unsigned int cpu)
                       ^

which not only has that duplicate inlining specifier, but the new
__always_inline was put in the wrong place of the function definition.

We put the storage class specifiers (ie things like "static" and
"extern") first, and the type information after that.  And while the
compiler may not care, we put the inline specifier before the types.

So it should be just

    static __always_inline void idle_init(unsigned int cpu)

instead.

Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull powerpc fixes from Michael Ellerman:

 - Fix guest to host memory corruption in H_RTAS due to missing nargs
   check.

 - Fix guest triggerable host crashes due to bad handling of nested
   guest TM state.

 - Fix possible crashes due to incorrect reference counting in
   kvm_arch_vcpu_ioctl().

 - Two commits fixing some regressions in KVM transactional memory
   handling introduced by the recent rework of the KVM code.

Thanks to Nicholas Piggin, Alexey Kardashevskiy, and Michael Neuling.

* tag 'powerpc-5.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  KVM: PPC: Book3S HV Nested: Sanitise H_ENTER_NESTED TM state
  KVM: PPC: Book3S: Fix H_RTAS rets buffer overflow
  KVM: PPC: Fix kvm_arch_vcpu_ioctl vcpu_load leak
  KVM: PPC: Book3S: Fix CONFIG_TRANSACTIONAL_MEM=n crash
  KVM: PPC: Book3S HV P9: Fix guest TM support

Pull timer fixes from Thomas Gleixner:
 "A small set of timer related fixes:

   - Plug a race between rearm and process tick in the posix CPU timers
     code

   - Make the optimization to avoid recalculation of the next timer
     interrupt work correctly when there are no timers pending"

* tag 'timers-urgent-2021-07-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timers: Fix get_next_timer_interrupt() with no timers pending
  posix-cpu-timers: Fix rearm racing against process tick

Pull x86 jump label fix from Thomas Gleixner:
 "A single fix for jump labels to prevent the compiler from agressive
  un-inlining which results in a section mismatch"

* tag 'locking-urgent-2021-07-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  jump_labels: Mark __jump_label_transform() as __always_inlined to work around aggressive compiler un-inlining

Pull EFI fixes from Thomas Gleixner:
 "A set of EFI fixes:

   - Prevent memblock and I/O reserved resources to get out of sync when
     EFI memreserve is in use.

   - Don't claim a non-existing table is invalid

   - Don't warn when firmware memory is already reserved correctly"

* tag 'efi-urgent-2021-07-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi/mokvar: Reserve the table only if it is in boot services data
  efi/libstub: Fix the efi_load_initrd function description
  firmware/efi: Tell memblock about EFI iomem reservations
  efi/tpm: Differentiate missing and invalid final event log table.

Pull core fix from Thomas Gleixner:
 "A single update for the boot code to prevent aggressive un-inlining
  which causes a section mismatch"

* tag 'core-urgent-2021-07-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  smpboot: Mark idle_init() as __always_inlined to work around aggressive compiler un-inlining

Pull dma-mapping fix from Christoph Hellwig:

 - handle vmalloc addresses in dma_common_{mmap,get_sgtable} (Roman
   Skakun)

* tag 'dma-mapping-5.14-1' of git://git.infradead.org/users/hch/dma-mapping:
  dma-mapping: handle vmalloc addresses in dma_common_{mmap,get_sgtable}

Pull cifs fixes from Steve French:
 "Five cifs/smb3 fixes, including a DFS failover fix, two fallocate
  fixes, and two trivial coverity cleanups"

* tag '5.14-rc2-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: fix fallocate when trying to allocate a hole.
  CIFS: Clarify SMB1 code for POSIX delete file
  CIFS: Clarify SMB1 code for POSIX Create
  cifs: support share failover when remounting
  cifs: only write 64kb at a time when fallocating a small region of a file

Pull RISC-V fixes from Palmer Dabbelt:

 - properly set the memory size, which fixes 32-bit systems

 - allow initrd to load anywhere in memory, rather that restricting it
   to the first 256MiB

 - fix the 'mem=' parameter on 64-bit systems to properly account for
   the maximum supported memory now that the kernel is outside the
   linear map

 - avoid installing mappings into the last 4KiB of memory, which
   conflicts with error values

 - avoid the stack from being freed while it is being walked

 - a handful of fixes to the new copy to/from user routines

* tag 'riscv-for-linus-5.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: __asm_copy_to-from_user: Fix: Typos in comments
  riscv: __asm_copy_to-from_user: Remove unnecessary size check
  riscv: __asm_copy_to-from_user: Fix: fail on RV32
  riscv: __asm_copy_to-from_user: Fix: overrun copy
  riscv: stacktrace: pin the task's stack in get_wchan
  riscv: Make sure the kernel mapping does not overlap with IS_ERR_VALUE
  riscv: Make sure the linear mapping does not use the kernel mapping
  riscv: Fix memory_limit for 64-bit kernel
  RISC-V: load initrd wherever it fits into memory
  riscv: Fix 32-bit RISC-V boot failure

Commit 71f64283 ("ACPI: utils: Fix reference counting in
for_each_acpi_dev_match()") started doing "acpi_dev_put()" on a pointer
that was possibly NULL.  That fails miserably, because that helper
inline function is not set up to handle that case.

Just make acpi_dev_put() silently accept a NULL pointer, rather than
calling down to put_device() with an invalid offset off that NULL
pointer.

Link: https://lore.kernel.org/lkml/a607c149-6bf6-0fd0-0e31-100378504da2@kernel.dk/Reported-and-tested-by: Jens Axboe <axboe@kernel.dk>
Tested-by: Daniel Scally <djrscally@gmail.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull SCSI fixes from James Bottomley:
 "Four fixes, all in drivers, all of which can lead to user visible
  problems in certain situations"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: target: Fix NULL dereference on XCOPY completion
  scsi: mpt3sas: Transition IOC to Ready state during shutdown
  scsi: target: Fix protect handling in WRITE SAME(32)
  scsi: iscsi: Fix iface sysfs attr detection

Pull io_uring fixes from Jens Axboe:

 - Fix a memory leak due to a race condition in io_init_wq_offload
   (Yang)

 - Poll error handling fixes (Pavel)

 - Fix early fdput() regression (me)

 - Don't reissue iopoll requests off release path (me)

 - Add a safety check for io-wq queue off wrong path (me)

* tag 'io_uring-5.14-2021-07-24' of git://git.kernel.dk/linux-block:
  io_uring: explicitly catch any illegal async queue attempt
  io_uring: never attempt iopoll reissue from release path
  io_uring: fix early fdput() of file
  io_uring: fix memleak in io_init_wq_offload()
  io_uring: remove double poll entry on arm failure
  io_uring: explicitly count entries for poll reqs

Pull block fixes from Jens Axboe:

 - NVMe pull request (Christoph):
    - tracing fix (Keith Busch)
    - fix multipath head refcounting (Hannes Reinecke)
    - Write Zeroes vs PI fix (me)
    - drop a bogus WARN_ON (Zhihao Cheng)

 - Increase max blk-cgroup policy size, now that mq-deadline
   uses it too (Oleksandr)

* tag 'block-5.14-2021-07-24' of git://git.kernel.dk/linux-block:
  nvme: set the PRACT bit when using Write Zeroes with T10 PI
  nvme: fix nvme_setup_command metadata trace event
  nvme: fix refcounting imbalance when all paths are down
  nvme-pci: don't WARN_ON in nvme_reset_work if ctrl.state is not RESETTING
  block: increase BLKCG_MAX_POLS

Pull i2c fixes from Wolfram Sang:
 "Two bugfixes for the I2C subsystem"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: mpc: Poll for MCF
  misc: eeprom: at24: Always append device id even if label property is set.