linux-toradex.git/drivers/tty/serial/amba-pl011.c, branch v5.15-rc2

Revert "arm pl011 serial: support multi-irq request"

2021-08-16T16:52:08+00:00

This reverts commit b0819465be8be0c76af15436a9e6db4dab4c196e which
results in amba_device-specific code being called from
sbsa_uart_startup() and sbsa_uart_shutdown().

Signed-off-by: Qian Cai 
Link: https://lore.kernel.org/r/20210813163135.205-1-quic_qiancai@quicinc.com
Signed-off-by: Greg Kroah-Hartman

arm pl011 serial: support multi-irq request

2021-07-21T10:39:47+00:00

In order to make pl011 work better, multiple interrupts are
required, such as TXIM, RXIM, RTIM, error interrupt(FE/PE/BE/OE);
at the same time, pl011 to GIC does not merge the interrupt
lines(each serial-interrupt corresponding to different GIC hardware
interrupt), so need to enable and request multiple gic interrupt
numbers in the driver.

Signed-off-by: Bing Fan 
Link: https://lore.kernel.org/r/1625103512-30182-1-git-send-email-hptsfb@gmail.com
Signed-off-by: Greg Kroah-Hartman

serial: amba-pl011: add RS485 support

2021-07-21T10:39:21+00:00

Add basic support for RS485: Provide a callback to configure RS485
settings. Handle the RS485 specific part in the functions
pl011_rs485_tx_start() and pl011_rs485_tx_stop() which extend the generic
start/stop callbacks.
Beside via IOCTL from userspace RS485 can be enabled by means of the
device tree property "rs485-enabled-at-boot-time".

Signed-off-by: Lino Sanfilippo 
Link: https://lore.kernel.org/r/20210630225644.3744-1-LinoSanfilippo@gmx.de
Signed-off-by: Greg Kroah-Hartman

serial: drop irq-flags initialisations

2021-05-20T14:24:05+00:00

There's no need to initialise irq-flags variables before saving the
interrupt state.

Drop the redundant initialisations from drivers that got this wrong.

Acked-by: Uwe Kleine-König 
Signed-off-by: Johan Hovold 
Link: https://lore.kernel.org/r/20210519092541.10137-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman

serial: amba-pl011: drop low-latency workaround

2021-04-22T10:09:24+00:00

Commit ead76f329f77 ("ARM: 6763/1: pl011: add optional RX DMA to PL011
v2") added RX DMA support and also reproduced the workaround for the
infamous low_latency behaviour of tty_flip_buffer_push() by dropping and
reacquiring the port lock during receive processing.

Since commit a9c3f68f3cd8 ("tty: Fix low_latency BUG"),
tty_flip_buffer_push() always schedules a work item to push data to the
line discipline and there's no need to keep any low_latency hacks around.

Note that the port lock is also dropped in the PIO path
(see pl011_rx_chars), but it is not clear whether this is still needed
by the DMA code added by the aforementioned commit.

Cc: Linus Walleij 
Cc: Russell King 
Reviewed-by: Linus Walleij 
Signed-off-by: Johan Hovold 
Link: https://lore.kernel.org/r/20210421095509.3024-6-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman

amba: Make the remove callback return void

2021-02-02T13:25:50+00:00

All amba drivers return 0 in their remove callback. Together with the
driver core ignoring the return value anyhow, it doesn't make sense to
return a value here.

Change the remove prototype to return void, which makes it explicit that
returning an error value doesn't work as expected. This simplifies changing
the core remove callback to return void, too.

Reviewed-by: Ulf Hansson 
Reviewed-by: Arnd Bergmann 
Acked-by: Alexandre Belloni 
Acked-by: Dmitry Torokhov 
Acked-by: Krzysztof Kozlowski  # for drivers/memory
Acked-by: Mark Brown 
Acked-by: Linus Walleij 
Acked-by: Suzuki K Poulose  # for hwtracing/coresight
Acked-By: Vinod Koul  # for dmaengine
Acked-by: Guenter Roeck  # for watchdog
Acked-by: Wolfram Sang  # for I2C
Acked-by: Takashi Iwai  # for sound
Acked-by: Vladimir Zapolskiy  # for memory/pl172
Acked-by: Greg Kroah-Hartman 
Link: https://lore.kernel.org/r/20210126165835.687514-5-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König

tty: serial: amba-pl011: Mark 'sbsa_uart_acpi_match' as __maybe_unused

2020-11-06T09:54:04+00:00

When !ACPI 'sbsa_uart_acpi_match' is not referenced.

Fixes the following W=1 kernel build warning(s):

 drivers/tty/serial/amba-pl011.c:2792:36: warning: ‘sbsa_uart_acpi_match’ defined but not used [-Wunused-const-variable=]

Cc: Russell King 
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Cc: linux-serial@vger.kernel.org
Signed-off-by: Lee Jones 
Link: https://lore.kernel.org/r/20201104193549.4026187-18-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman

serial: pl011: Fix lockdep splat when handling magic-sysrq interrupt

2020-09-30T12:31:04+00:00

Issuing a magic-sysrq via the PL011 causes the following lockdep splat,
which is easily reproducible under QEMU:

  | sysrq: Changing Loglevel
  | sysrq: Loglevel set to 9
  |
  | ======================================================
  | WARNING: possible circular locking dependency detected
  | 5.9.0-rc7 #1 Not tainted
  | ------------------------------------------------------
  | systemd-journal/138 is trying to acquire lock:
  | ffffab133ad950c0 (console_owner){-.-.}-{0:0}, at: console_lock_spinning_enable+0x34/0x70
  |
  | but task is already holding lock:
  | ffff0001fd47b098 (&port_lock_key){-.-.}-{2:2}, at: pl011_int+0x40/0x488
  |
  | which lock already depends on the new lock.

  [...]

  |  Possible unsafe locking scenario:
  |
  |        CPU0                    CPU1
  |        ----                    ----
  |   lock(&port_lock_key);
  |                                lock(console_owner);
  |                                lock(&port_lock_key);
  |   lock(console_owner);
  |
  |  *** DEADLOCK ***

The issue being that CPU0 takes 'port_lock' on the irq path in pl011_int()
before taking 'console_owner' on the printk() path, whereas CPU1 takes
the two locks in the opposite order on the printk() path due to setting
the "console_owner" prior to calling into into the actual console driver.

Fix this in the same way as the msm-serial driver by dropping 'port_lock'
before handling the sysrq.

Cc:  # 4.19+
Cc: Russell King 
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Link: https://lore.kernel.org/r/20200811101313.GA6970@willie-the-truck
Signed-off-by: Peter Zijlstra 
Tested-by: Will Deacon 
Signed-off-by: Will Deacon 
Link: https://lore.kernel.org/r/20200930120432.16551-1-will@kernel.org
Signed-off-by: Greg Kroah-Hartman

serial: pl011: Fix oops on -EPROBE_DEFER

2020-08-18T11:32:27+00:00

If probing of a pl011 gets deferred until after free_initmem(), an oops
ensues because pl011_console_match() is called which has been freed.

Fix by removing the __init attribute from the function and those it
calls.

Commit 10879ae5f12e ("serial: pl011: add console matching function")
introduced pl011_console_match() not just for early consoles but
regular preferred consoles, such as those added by acpi_parse_spcr().
Regular consoles may be registered after free_initmem() for various
reasons, one being deferred probing, another being dynamic enablement
of serial ports using a DeviceTree overlay.

Thus, pl011_console_match() must not be declared __init and the
functions it calls mustn't either.

Stack trace for posterity:

Unable to handle kernel paging request at virtual address 80c38b58
Internal error: Oops: 8000000d [#1] PREEMPT SMP ARM
PC is at pl011_console_match+0x0/0xfc
LR is at register_console+0x150/0x468
[<80187004>] (register_console)
[<805a8184>] (uart_add_one_port)
[<805b2b68>] (pl011_register_port)
[<805b3ce4>] (pl011_probe)
[<80569214>] (amba_probe)
[<805ca088>] (really_probe)
[<805ca2ec>] (driver_probe_device)
[<805ca5b0>] (__device_attach_driver)
[<805c8060>] (bus_for_each_drv)
[<805c9dfc>] (__device_attach)
[<805ca630>] (device_initial_probe)
[<805c90a8>] (bus_probe_device)
[<805c95a8>] (deferred_probe_work_func)

Fixes: 10879ae5f12e ("serial: pl011: add console matching function")
Signed-off-by: Lukas Wunner 
Cc: stable@vger.kernel.org # v4.10+
Cc: Aleksey Makarov 
Cc: Peter Hurley 
Cc: Russell King 
Cc: Christopher Covington 
Link: https://lore.kernel.org/r/f827ff09da55b8c57d316a1b008a137677b58921.1597315557.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman

serial: pl011: Don't leak amba_ports entry on driver register error

2020-08-18T11:32:27+00:00

pl011_probe() calls pl011_setup_port() to reserve an amba_ports[] entry,
then calls pl011_register_port() to register the uart driver with the
tty layer.

If registration of the uart driver fails, the amba_ports[] entry is not
released.  If this happens 14 times (value of UART_NR macro), then all
amba_ports[] entries will have been leaked and driver probing is no
longer possible.  (To be fair, that can only happen if the DeviceTree
doesn't contain alias IDs since they cause the same entry to be used for
a given port.)   Fix it.

Fixes: ef2889f7ffee ("serial: pl011: Move uart_register_driver call to device")
Signed-off-by: Lukas Wunner 
Cc: stable@vger.kernel.org # v3.15+
Cc: Tushar Behera 
Link: https://lore.kernel.org/r/138f8c15afb2f184d8102583f8301575566064a6.1597316167.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman