In the previous patch, we introduced tty_get_char_size() and
tty_get_frame_size() for computing character and frame sizes,
respectively. Here, we make use of them in various tty drivers where
applicable.

The stats look nice: 12 insertions, 169 deletions.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Lin <dtwlin@gmail.com>
Cc: Johan Hovold <johan@kernel.org>
Cc: Alex Elder <elder@kernel.org>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Andy Gross <agross@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Oliver Neukum <oneukum@suse.com>
Acked-by: NAlex Elder <elder@kernel.org>
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210610090247.2593-4-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Stop dmaengine transfer in sci_stop_tx(). Otherwise, the following
message is possible output when system enters suspend and while
transferring data, because clearing TIE bit in SCSCR is not able to
stop any dmaengine transfer.

    sh-sci e6550000.serial: ttySC1: Unable to drain transmitter

Note that this driver has already used some #ifdef in the .c file
so that this patch also uses #ifdef to fix the issue. Otherwise,
build errors happens if the CONFIG_SERIAL_SH_SCI_DMA is disabled.

Fixes: 73a19e4c ("serial: sh-sci: Add DMA support.")
Cc: <stable@vger.kernel.org> # v4.9+
Signed-off-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20210610110806.277932-1-yoshihiro.shimoda.uh@renesas.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The last user of the STEPFN() macro was removed in commit
d5cb1319 ("serial: sh-sci: Remove manual break debouncing").
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: NNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/970387d104dea5bb7ea674bb89229641467e629b.1623076891.git.geert+renesas@glider.beSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add serial support for RZ/G2L SoC with earlycon and
extended mode register support.
Signed-off-by: NBiju Das <biju.das.jz@bp.renesas.com>
Signed-off-by: NLad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20210603221758.10305-11-prabhakar.mahadev-lad.rj@bp.renesas.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 064b6e47 as it
wasn't quite ready yet :(

Cc: Biju Das <biju.das.jz@bp.renesas.com>
CC: Geert Uytterhoeven <geert+renesas@glider.be>
Reported-by: NLad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add serial support for RZ/G2L SoC with earlycon and
extended mode register support.
Signed-off-by: NBiju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: NLad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20210514192218.13022-11-prabhakar.mahadev-lad.rj@bp.renesas.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The Receive FIFO Data Count Trigger field (RTRG[6:0]) in the Receive
FIFO Data Count Trigger Register (HSRTRGR) of HSCIF can only hold values
ranging from 0-127.  As the FIFO size is equal to 128 on HSCIF, the user
can write an out-of-range value, touching reserved bits.

Fix this by limiting the trigger value to the FIFO size minus one.
Reverse the order of the checks, to avoid rx_trig becoming zero if the
FIFO size is one.

Note that this change has no impact on other SCIF variants, as their
maximum supported trigger value is lower than the FIFO size anyway, and
the code below takes care of enforcing these limits.

Fixes: a380ed46 ("serial: sh-sci: implement FIFO threshold register setting")
Reported-by: NLinh Phung <linh.phung.jy@renesas.com>
Reviewed-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NUlrich Hecht <uli+renesas@fpond.eu>
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/5eff320aef92ffb33d00e57979fd3603bbb4a70f.1620648218.git.geert+renesas@glider.beSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since the transition to hrtimers there is no more need to set a minimum
RX timeout to work around latency issues.
Reviewed-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: NUlrich Hecht <uli+renesas@fpond.eu>
Link: https://lore.kernel.org/r/20210415093547.21639-1-uli+renesas@fpond.euSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

wheter -> whether
Signed-off-by: NWang Qing <wangqing@vivo.com>
Link: https://lore.kernel.org/r/1615345622-2015-1-git-send-email-wangqing@vivo.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit f38278e9.

There has been a quick fix against uninitialised lock revealed by
the commit f743061a ("serial: core: Initialise spin lock before use
in uart_configure_port()"). Since we have now better fix in serial core,
this may be safely reverted.

Fixes: f38278e9 ("serial: sh-sci: Initialize spinlock for uart console")
Depends-on: f743061a ("serial: core: Initialise spin lock before use in uart_configure_port()")
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200711135346.71171-5-andriy.shevchenko@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

serial core expects the spinlock to be initialized by the controller
driver for serial console, this patch makes sure the spinlock is
initialized, fixing the below issue:

[    0.865928] BUG: spinlock bad magic on CPU#0, swapper/0/1
[    0.865945]  lock: sci_ports+0x0/0x4c80, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
[    0.865955] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.8.0-rc1+ #112
[    0.865961] Hardware name: HopeRun HiHope RZ/G2H with sub board (DT)
[    0.865968] Call trace:
[    0.865979]  dump_backtrace+0x0/0x1d8
[    0.865985]  show_stack+0x14/0x20
[    0.865996]  dump_stack+0xe8/0x130
[    0.866006]  spin_dump+0x6c/0x88
[    0.866012]  do_raw_spin_lock+0xb0/0xf8
[    0.866023]  _raw_spin_lock_irqsave+0x80/0xa0
[    0.866032]  uart_add_one_port+0x3a4/0x4e0
[    0.866039]  sci_probe+0x504/0x7c8
[    0.866048]  platform_drv_probe+0x50/0xa0
[    0.866059]  really_probe+0xdc/0x330
[    0.866066]  driver_probe_device+0x58/0xb8
[    0.866072]  device_driver_attach+0x6c/0x90
[    0.866078]  __driver_attach+0x88/0xd0
[    0.866085]  bus_for_each_dev+0x74/0xc8
[    0.866091]  driver_attach+0x20/0x28
[    0.866098]  bus_add_driver+0x14c/0x1f8
[    0.866104]  driver_register+0x60/0x110
[    0.866109]  __platform_driver_register+0x40/0x48
[    0.866119]  sci_init+0x2c/0x34
[    0.866127]  do_one_initcall+0x88/0x428
[    0.866137]  kernel_init_freeable+0x2c0/0x328
[    0.866143]  kernel_init+0x10/0x108
[    0.866150]  ret_from_fork+0x10/0x18
Signed-off-by: NLad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: NBiju Das <biju.das.jz@bp.renesas.com>
Fixes: a3cb39d2 ("serial: core: Allow detach and attach serial device for console")
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/1593618100-2151-1-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

For SCIF and HSCIF interfaces the SCxSR register holds the status of
data that is to be read next from SCxRDR register, But where as for
SCIFA and SCIFB interfaces SCxSR register holds status of data that is
previously read from SCxRDR register.

This patch makes sure the status register is read depending on the port
types so that errors are caught accordingly.

Cc: <stable@vger.kernel.org>
Signed-off-by: NKazuhiro Fujita <kazuhiro.fujita.jg@renesas.com>
Signed-off-by: NHao Bui <hao.bui.yg@renesas.com>
Signed-off-by: NKAZUMI HARADA <kazumi.harada.rh@renesas.com>
Signed-off-by: NLad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Tested-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/1585333048-31828-1-git-send-email-kazuhiro.fujita.jg@renesas.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

ioremap has provided non-cached semantics by default since the Linux 2.6
days, so remove the additional ioremap_nocache interface.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NArnd Bergmann <arnd@arndb.de>

The SUPPORT_SYSRQ ifdeffery is not nice as:
- May create misunderstanding about sizeof(struct uart_port) between
  different objects
- Prevents moving functions from serial_core.h
- Reduces readability (well, it's ifdeffery - it's hard to follow)

In order to remove SUPPORT_SYSRQ, has_sysrq variable has been added.
Initialise it in driver's probe and remove ifdeffery.
Signed-off-by: NDmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20191213000657.931618-42-dima@arista.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Old early platform device support is now sh-specific. Before moving on
to implementing new early platform framework based on real platform
devices, prefix all early platform symbols with 'sh_'.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Rich Felker <dalias@libc.org>
Link: https://lore.kernel.org/r/20191003092913.10731-3-brgl@bgdev.plSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

SuperH is the only user of the current implementation of early platform
device support. We want to introduce a more robust approach to early
probing. As the first step - move all the current early platform code
to arch/sh.

In order not to export internal drivers/base functions to arch code for
this temporary solution - copy the two needed routines for driver
matching from drivers/base/platform.c to arch/sh/drivers/platform_early.c.

Also: call early_platform_cleanup() from subsys_initcall() so that it's
called after all early devices are probed.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Rich Felker <dalias@libc.org>
Link: https://lore.kernel.org/r/20191003092913.10731-2-brgl@bgdev.plSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As platform_get_irq() now prints an error when the interrupt does not
exist, scary warnings may be printed for optional interrupts:

    sh-sci e6550000.serial: IRQ index 1 not found
    sh-sci e6550000.serial: IRQ index 2 not found
    sh-sci e6550000.serial: IRQ index 3 not found
    sh-sci e6550000.serial: IRQ index 4 not found
    sh-sci e6550000.serial: IRQ index 5 not found

Fix this by calling platform_get_irq_optional() instead for all but the
first interrupts, which are optional.

Fixes: 7723f4c5 ("driver core: platform: Add an error message to platform_get_irq*()")
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NStephen Boyd <swboyd@chromium.org>
Reviewed-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20191001180743.1041-1-geert+renesas@glider.beSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since commit 1d267ea6 ("serial: mctrl-gpio: simplify init
routine"), mctrl_gpio_init() returns failure if the assignment to any
member of the gpio array results in an error pointer.
Since commit c359522194593815 ("serial: mctrl_gpio: Avoid probe failures
in case of missing gpiolib"), mctrl_gpio_to_gpiod() returns NULL in the
!CONFIG_GPIOLIB case.
Hence there is no longer a need to check for mctrl_gpio_to_gpiod()
returning an error value.  A simple NULL check is sufficient.

This follows the spirit of commit 445df7ff ("serial: mctrl-gpio:
drop usages of IS_ERR_OR_NULL") in the mctrl-gpio core.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20190814092924.13857-4-geert+renesas@glider.beSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Now that the mctrl_gpio code returns NULL instead of ERR_PTR(-ENOSYS)
if CONFIG_GPIOLIB is disabled, we can safely remove this check.
Signed-off-by: NFrieder Schrempf <frieder.schrempf@kontron.de>
Acked-by: NUwe Kleine-Knig <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20190802100349.8659-3-frieder.schrempf@kontron.deSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

While commit b6b996b6 ("treewide: Use DEVICE_ATTR_RW") converted
the rx_fifo_timeout attribute, it forgot to convert rx_fifo_trigger due
to a slightly different function naming.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NUlrich Hecht <uli+renesas@fpond.eu>
Link: https://lore.kernel.org/r/20190731124555.14349-1-geert+renesas@glider.beSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This is a driver, do not call "raw" sysfs functions, instead call driver
core ones.  Specifically convert the use of sysfs_create_file() and
sysfs_remove_file() to use device_create_file() and device_remove_file()

Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org
Link: https://lore.kernel.org/r/20190704084617.3602-4-gregkh@linuxfoundation.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

While the .flush_buffer() callback clears sci_port.tx_dma_len since
commit 1cf4a7ef ("serial: sh-sci: Fix race condition causing
garbage during shutdown"), it does not terminate a transmit DMA
operation that may be in progress.

Fix this by terminating any pending DMA operations, and resetting the
corresponding cookie.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NEugeniu Rosca <erosca@de.adit-jv.com>
Tested-by: NEugeniu Rosca <erosca@de.adit-jv.com>

Link: https://lore.kernel.org/r/20190624123540.20629-3-geert+renesas@glider.beSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When uart_flush_buffer() is called, the .flush_buffer() callback zeroes
the tx_dma_len field.  This may race with the work queue function
handling transmit DMA requests:

  1. If the buffer is flushed before the first DMA API call,
     dmaengine_prep_slave_single() may be called with a zero length,
     causing the DMA request to never complete, leading to messages
     like:

        rcar-dmac e7300000.dma-controller: Channel Address Error happen

     and, with debug enabled:

	sh-sci e6e88000.serial: sci_dma_tx_work_fn: ffff800639b55000: 0...0, cookie 126

     and DMA timeouts.

  2. If the buffer is flushed after the first DMA API call, but before
     the second, dma_sync_single_for_device() may be called with a zero
     length, causing the transmit data not to be flushed to RAM, and
     leading to stale data being output.

Fix this by:
  1. Letting sci_dma_tx_work_fn() return immediately if the transmit
     buffer is empty,
  2. Extending the critical section to cover all DMA preparational work,
     so tx_dma_len stays consistent for all of it,
  3. Using local copies of circ_buf.head and circ_buf.tail, to make sure
     they match the actual operation above.
Reported-by: NEugeniu Rosca <erosca@de.adit-jv.com>
Suggested-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NEugeniu Rosca <erosca@de.adit-jv.com>
Tested-by: NEugeniu Rosca <erosca@de.adit-jv.com>
Link: https://lore.kernel.org/r/20190624123540.20629-2-geert+renesas@glider.beSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As noted in commit 84b40e3b ("serial: 8250: omap: Disable DMA for
console UART"), UART console lines use low-level PIO only access functions
which will conflict with use of the line when DMA is enabled, e.g. when
the console line is also used for systemd messages. So disable DMA
support for UART console lines.
Reported-by: NMichael Rodin <mrodin@de.adit-jv.com>
Link: https://patchwork.kernel.org/patch/10929511/Tested-by: NEugeniu Rosca <erosca@de.adit-jv.com>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Reviewed-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Cc: stable@vger.kernel.org
Signed-off-by: NGeorge G. Davis <george_davis@mentor.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The calculation of the sampling point has min() and max() exchanged.
Fix this by using the clamp() helper instead.

Fixes: 63ba1e00 ("serial: sh-sci: Support for HSCIF RX sampling point adjustment")
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NUlrich Hecht <uli+renesas@fpond.eu>
Reviewed-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NDirk Behme <dirk.behme@de.bosch.com>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There are several issues with the formula used for calculating the
deviation from the intended rate:
  1. While min_err and last_stop are signed, srr and baud are unsigned.
     Hence the signed values are promoted to unsigned, which will lead
     to a bogus value of deviation if min_err is negative,
  2. Srr is the register field value, which is one less than the actual
     sampling rate factor,
  3. The divisions do not use rounding.

Fix this by casting unsigned variables to int, adding one to srr, and
using a single DIV_ROUND_CLOSEST().

Fixes: 63ba1e00 ("serial: sh-sci: Support for HSCIF RX sampling point adjustment")
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NMukesh Ojha <mojha@codeaurora.org>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: NUlrich Hecht <uli+renesas@fpond.eu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We disable transmission interrupt (clear SCSCR_TIE) after all data has been transmitted
(if uart_circ_empty(xmit)). While transmitting, if the data is still in the tty buffer,
re-enable the SCSCR_TIE bit, which was done at sci_start_tx().
This is unnecessary processing, wasting CPU operation if the data transmission length is large.
And further, transmit end, FIFO empty bits disabling have also been performed in the step above.
Signed-off-by: NHoan Nguyen An <na-hoan@jinso.co.jp>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since IRQs might be muxed on some parts, we need to pay attention when we
are freeing them.
Otherwise we get the ugly WARNING "Trying to free already-free IRQ 20".

Fixes: 628c534a ("serial: sh-sci: Improve support for separate TEI and DRI interrupts")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NChris Brandt <chris.brandt@renesas.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Most RX/TX-specific DMA functions are prefixed with "sci_dma_[rt]x_".
Rename the exceptions to increase consistency.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When submitting a DMA request fails in sci_dma_rx_complete(), the driver
tries to fall back to PIO, but that does not work: no more data will be
received, or the kernel will even crash.

Fix this similar as in (but not identical to) sci_submit_rx():
  - On SCIF, PIO cannot take over if any DMA transactions are pending,
    hence they must be terminated first.
  - All active cookies must be invalidated, else rx_timer_fn() may
    trigger a NULL pointer dereference.
  - Restarting the port is not needed, as it is already running, but
    serial port interrupts must be directed back from the DMA engine to
    the CPU.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Extract the functionality to direct new serial port interrupts back to
the CPU into its own helper, to prepare for using it from a second
callsite.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The cookies and channel pointer for the DMA receive channel are
invalidated in two places, and one more is planned.
Extract this functionality in a common helper.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

On (H)SCIF, sci_submit_rx() is called in the receive interrupt handler.
Hence if DMA submission fails, the interrupt handler should resume
handling reception using PIO, else no more data is received.

Make sci_submit_rx() return an error indicator, so the receive interrupt
handler can act appropriately.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Acked-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When falling back to PIO, active_rx must be set to a different value
than cookie_rx[i], else sci_dma_rx_find_active() will incorrectly find a
match, leading to a NULL pointer dereference in rx_timer_fn() later.

Use zero instead, which is the same value as after driver
initialization.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Some callers of sci_submit_rx() hold the port spinlock, others don't.
During fallback to PIO, the driver needs to obtain the port spinlock.
If the lock was already held, spinlock recursion is detected, causing a
deadlock: BUG: spinlock recursion on CPU#0.

Fix this by adding a flag parameter to sci_submit_rx() for the caller to
indicate the port spinlock is already held, so spinlock recursion can be
avoided.

Move the spin_lock_irqsave() up, so all DMA disable steps are protected,
which is safe as the recently introduced dmaengine_terminate_async() can
be called in atomic context.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch fixes an issue that the sci_remove() could not remove
dev_attr_rx_fifo_timeout because uart_remove_one_port() set
the port->port.type to PORT_UNKNOWN.
Reported-by: NHiromitsu Yamasaki <hiromitsu.yamasaki.ym@renesas.com>
Fixes: 5d23188a ("serial: sh-sci: make RX FIFO parameters tunable via sysfs")
Cc: <stable@vger.kernel.org> # v4.11+
Signed-off-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: NUlrich Hecht <uli+renesas@fpond.eu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

While ptr and port both point to the uart_port structure, the former is
the untyped pointer cookie passed to interrupt handlers.
Use the correctly typed port variable instead, to improve type-safety.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NUlrich Hecht <uli+renesas@fpond.eu>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

On SCIFA and SCIFB serial ports with DMA support (i.e. some ports on
R-Car Gen2 and RZ/G1 SoCs), receive DMA operations are submitted before
the DMA channel pointer is initialized.  Hence this fails, and the
driver tries to fall back to PIO.  However, at this early phase in the
initialization sequence, fallback to PIO does not work, leading to a
serial port that cannot receive any data.

Fix this by calling sci_submit_rx() after initialization of the DMA
channel pointer.
Reported-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Fixes: 2c4ee235 ("serial: sh-sci: Postpone DMA release when falling back to PIO")
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Not all (H)SCIF devices support DMA, and failure to set it up is not
normally a cause for concern. This patch demotes the associated warning to
debug output.

Inspired by BSP patch "sci: sh-sci: Fix transfer sequence of unsupport DMA
transfer" (6beb1f98d3bd30) by Hiromitsu Yamasaki.
Signed-off-by: NUlrich Hecht <uli+renesas@fpond.eu>
Reviewed-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 2d4dd0da.

This broke earlycon on all Renesas ARM platforms using a SCIF port for the
serial console (R-Car, RZ/A1, RZ/G1, RZ/G2 SoCs), due to an incorrect value
of port->regshift.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NChris Brandt <chris.brandt@renesas.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>