Commit Graph

98 Commits

Author SHA1 Message Date
Graeme Gregory 3db9ab0b6d drivers: PL011: add ACPI probing for SBSA UART
Add the necessary driver boilerplate to let the driver be used when
the respective ACPI table is discovered by the ACPI subsystem.

[Andre: change table name, add MODULE_DEVICE_TABLE entry and improve
	commit message]

Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-24 13:08:51 -07:00
Andre Przywara 0dd1e247fd drivers: PL011: add support for the ARM SBSA generic UART
The ARM Server Base System Architecture[1] document describes a
generic UART which is a subset of the PL011 UART.
It lacks DMA support, baud rate control and modem status line
control, among other things.
The idea is to move the UART initialization and setup into the
firmware (which does this job today already) and let the kernel just
use the UART for sending and receiving characters.

We use the recent refactoring to build a new struct uart_ops
variable which points to some new functions avoiding access to the
missing registers. We reuse as much existing PL011 code as possible.

In contrast to the PL011 the SBSA UART does not define any AMBA or
PrimeCell relations, so we go with a pretty generic probe function
which only uses platform device functions.
A DT binding is provided with this patch, ACPI support is added in a
separate one.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-24 13:08:51 -07:00
Andre Przywara cefc2d1d66 drivers: PL011: allow to supply fixed option string
The SBSA UART has a fixed baud rate and flow control setting, which
cannot be changed or queried by software.
Add a vendor specific property to always return fixed values when
trying to read the console options.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-24 13:08:51 -07:00
Andre Przywara 71eec4836b drivers: PL011: allow avoiding UART enabling/disabling
The SBSA UART should not be enabled or disabled (it is always on),
and consequently the spec lacks the UART_CR register.
Add a vendor specific property to skip disabling or enabling of the
UART. This will be used later by the SBSA UART support.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-24 13:08:51 -07:00
Andre Przywara 9c4ef4b030 drivers: PL011: move cts_event workaround into separate function
To avoid lines with more than 80 characters and to make the
pl011_int() function more readable, move the workaround out into a
separate function.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-24 13:08:51 -07:00
Andre Przywara 075167ed71 drivers: PL011: replace UART_MIS reading with _RIS & _IMSC
The PL011 register UART_MIS is actually a bitwise AND of the
UART_RIS and the UART_MISC register.
Since the SBSA UART does not include the _MIS register, use the
two separate registers to get the same behaviour. Since we are
inside the spinlock and we read the _IMSC register only once, there
should be no race issue.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-24 13:08:51 -07:00
Andre Przywara 3873e2d7f6 drivers: PL011: refactor pl011_probe()
Currently the pl011_probe() function is relying on some AMBA IDs
and a device tree node to initialize the driver and a port.
Both features are not necessarily required for the driver:
- we lack AMBA IDs in the ARM SBSA generic UART and
- we lack a DT node in ACPI systems.
So lets refactor the function to ease later reuse.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-24 13:08:51 -07:00
Andre Przywara ef5a935884 drivers: PL011: refactor pl011_set_termios()
Split the pl011_set_termios() function into smaller chunks to allow
easier reuse later when adding SBSA support.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-24 13:08:51 -07:00
Andre Przywara 95166a3fd5 drivers: PL011: refactor pl011_shutdown()
Split the pl011_shutdown() function into smaller chunks to allow
easier reuse later when adding SBSA support.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-24 13:08:50 -07:00
Andre Przywara 867b8e8e89 drivers: PL011: refactor pl011_startup()
Split the pl011_startup() function into smaller chunks to allow
easier reuse later when adding SBSA support.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-24 13:08:50 -07:00
Andre Przywara 49bb3c862c drivers: PL011: avoid potential unregister_driver call
Although we care about not unregistering the driver if there are
still ports connected during the .remove callback, we do miss this
check in the pl011_probe function. So if the current port allocation
fails, but there are other ports already registered, we will kill
those.
So factor out the port removal into a separate function and use that
in the probe function, too.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-24 13:08:50 -07:00
Dave Martin fa8cd0f61f serial/amba-pl011: Fix mismerge between v4.1-rc4 and tty-next
In commit 02730d3c05
(Merge 4.1-rc4 into tty-next), git mismerged some lines,
reintroducing a reference to the removed field
uart_amba_port.tx_irq_seen.  This causes a build failure.

This patch removes the mismerged lines, restoring the code to what
was in tty-next (which was the intention).

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-19 16:42:10 -07:00
Greg Kroah-Hartman 02730d3c05 Merge 4.1-rc4 into tty-next
This resolves some tty driver merge issues.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-18 14:08:58 -07:00
Dave Martin ec61847855 Revert "serial/amba-pl011: Leave the TX IRQ alone when the UART is not open"
This reverts commit f2ee6dfa0e.

Jakub Kiciński observed that this patch can cause the pl011
driver to hang if if the only process with a pl011 port open is
killed by a signal, pl011_shutdown() can get called with an
arbitrary amount of data still in the FIFO.

Calling _shutdown() with the TX FIFO non-empty is questionable
behaviour and my itself be a bug.

Since the affected patch was speculative anyway, and brings limited
benefit, the simplest course is to remove the assumption that TXIS
will always be left asserted after the port is shut down.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-09 18:36:36 +02:00
Dave Martin 1e84d22322 serial/amba-pl011: Refactor and simplify TX FIFO handling
Commit 734745c serial/amba-pl011: Activate TX IRQ passively
adds some complexity and overhead in the form of a softirq
mechanism for transmitting in the absence of interrupts.

This patch simplifies the code flow to reduce the reliance on
subtle behaviour and avoid fragility under future maintenance.

To this end, the TX softirq mechanism is removed and instead
pl011_start_tx() will now simply stuff the FIFO until full
(guaranteeing future TX IRQs), or until there are no more chars
to write (in which case we don't care whether an IRQ happens).

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-06 22:26:56 +02:00
Dave Martin f28c1d0a78 Revert "serial/amba-pl011: Leave the TX IRQ alone when the UART is not open"
This reverts commit f2ee6dfa0e.

Jakub Kiciński observed that this patch can cause the pl011
driver to hang if if the only process with a pl011 port open is
killed by a signal, pl011_shutdown() can get called with an
arbitrary amount of data still in the FIFO.

Calling _shutdown() with the TX FIFO non-empty is questionable
behaviour and my itself be a bug.

Since the affected patch was speculative anyway, and brings limited
benefit, the simplest course is to remove the assumption that TXIS
will always be left asserted after the port is shut down.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-06 22:26:56 +02:00
Jorge Ramirez-Ortiz 48d7ff0eaa drivers/tty: serial: remove info message
Unacceptable levels of debug info will happen when the DMA driver defined in
the DT/ACPI is a blacklisted module.

Another cause for log polution would be the defer probing of the DMA driver
taking too long - in which case the message that this commit removes would be
cluttering the logs due to the init daemons activity.

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-11 16:38:25 +01:00
Jorge Ramirez-Ortiz 1c9be31015 drivers/tty: amba: defer DMA probe until the DMA channel is required.
Fix a race condition that happens when device_initcall(pl011_dma_initicall)
is executed before all the devices have been probed - this issue was observed on
a hisi_6220 SoC (HiKey board from Linaro).

The deferred driver probing framework relies on late_initcall to trigger
deferred probes so it is just possible that, even with a valid DMA driver ready
to be loaded, we fail to synchronize with it.

The proposed implementation delays probing the DMA until dma_startup.

As this is invoked on port startup and port resume - but DMA probing is only
required once - we avoid calling multiple times using a new field in
uart_amba_port to track this scenario.

This commit allows for subsequent attempts to associate an external DMA if the
DMA driver itself is not available (but present in the deferred probe pending
list).

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-07 03:50:30 +01:00
Dave Martin f2ee6dfa0e serial/amba-pl011: Leave the TX IRQ alone when the UART is not open
Getting the TX IRQ re-asserted from scratch can be inefficient in
some setups.

This patch avoids clearing the TX IRQ across pl011_shutdown()...
pl011_startup(), so that if the port is closed and reopened, the
IRQ will still work afterwards without having to bootstrap it again.

The TX IRQ continues to be masked in IMSC when the UART is not in
use.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Tested-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-07 03:48:50 +01:00
Dave Martin 734745caeb serial/amba-pl011: Activate TX IRQ passively
The current PL011 driver transmits a dummy character when the UART
is opened, to assert the TX IRQ for the first time
(see pl011_startup()).  The UART is put in loopback mode temporarily,
so the receiver presumably shouldn't see anything.

However...

At least some platforms containing a PL011 send characters down the
wire even when loopback mode is enabled.  This means that a
spurious NUL character may be seen at the receiver when the PL011 is
opened through the TTY layer.

The current code also temporarily sets the baud rate to maximum and
the character width to the minimum, to that the dummy TX completes
as quickly as possible.  If this is seen by the receiver it will
result in a framing error and can knock the receiver out of sync --
turning subsequent output into garbage until synchronisation
is reestablished.  (Particularly problematic during boot with systemd.)

To avoid spurious transmissions, this patch removes assumptions about
whether the TX IRQ will fire until at least one TX IRQ has been seen.

Instead, the UART will unmask the TX IRQ and then slow-start via
polling and timer-based soft IRQs initially.  If the TTY layer writes
enough data to fill the FIFO to the interrupt threshold in one go,
the TX IRQ should assert, at which point the driver changes to
fully interrupt-driven TX.

In this way, the TX IRQ is activated as a side-effect instead of
being done deliberately.

This should also mean that the driver works on the SBSA Generic
UART[1] (a cut-down PL011) without invasive changes.  The Generic
UART lacks some features needed for the dummy TX approach to work
(FIFO disabling and loopback).

[1] Server Base System Architecture (ARM-DEN-0029-v2.3)
    http://infocenter.arm.com/
    (click-thru required :/)

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Tested-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-07 03:48:50 +01:00
Andrew Jackson 98267d33e2 serial: pl011: Add device tree support for RX DMA polling
Add equivalent attributes to those provided in the platform data
for use when RX DMA is enabled.

Signed-off-by: Andrew Jackson <Andrew.Jackson@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-07 08:35:56 -08:00
Andrew Jackson 2d3b7d6e7d serial: pl011: Don't enable RX DMA if residue processing not supported
If the DMA engine doesn't support residue processing then the RX DMA
handling won't work terribly well if polling is enabled.  So, disable
RX DMA if residue handling isn't available.

Signed-off-by: Andrew Jackson <Andrew.Jackson@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-07 08:35:56 -08:00
Andrew Jackson c64be9231e serial: pl011: Set length of DMA transfer
The DMA engines on some systems require that the dma_length is set
when using scatter gather lists.

Signed-off-by: Andrew Jackson <Andrew.Jackson@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-07 08:35:55 -08:00
Andrew Jackson e2a545a6ae serial: pl011: Avoid assumptions about buffer size when refilling TX DMA
The existing code assumed that PL011_DMA_BUFFER_SIZE == UART_XMIT_SIZE,
which may not always be the case.  This allows for these two being
different sizes and not copying too much data.

Signed-off-by: Andrew Jackson <Andrew.Jackson@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-07 08:35:55 -08:00
Andrew Jackson 4c0be45b18 serial: pl011: Allocate TX DMA buffer from DMA capable memory
Allocating with __GFP_DMA avoids the need for bounce buffers

Signed-off-by: Andrew Jackson <Andrew.Jackson@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-07 08:35:55 -08:00
Peter Hurley 36f339d136 serial: pl011: Fix build breakage with !CONFIG_DMA_ENGINE
Commit 479e9b94fd ("serial: Refactor uart_flush_buffer() from
uart_close") refactored the uart_flush_buffer() in uart_close() into
those drivers that define a flush_buffer() method. However, in the
amba-pl011 driver configured without CONFIG_DMA_ENGINE, flush_buffer()
is a NULL method, so the direct call fails to compile.

Check and call the flush_buffer() method through the ops table instead.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-06 09:35:54 -08:00
Peter Hurley 479e9b94fd serial: Refactor uart_flush_buffer() from uart_close()
In the context of the final tty & port close, flushing the tx
ring buffer after the hardware has already been shutdown and
the ring buffer freed is neither required nor desirable.

uart_flush_buffer() performs 3 operations:
1. Resets tx ring buffer indices, but the tx ring buffer has
   already been freed and the indices are reset if the port is
   re-opened.
2. Calls uart driver's flush_buffer() method
   5 in-tree uart drivers define flush_buffer() methods:
     amba-pl011, atmel-serial, imx, serial-tegra, timbuart
   These have been refactored into the shutdown() method, if
   required.
3. Kicks the ldisc for more writing, but this is undesirable.
   The file handle is being released; any waiting writer will
   will be kicked out by tty_release() with a warning. Further,
   the N_TTY ldisc may generate SIGIO for a file handle which
   is no longer valid.

Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 18:53:54 -08:00
Daniel Thompson a5820c24a8 serial: amba-pl011: Use container_of() to get uart_amba_port
Universally adopt container_of() for all pointer conversion from
uart_port to uart_amba_port.

Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-serial@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-08 16:26:07 -07:00
Tushar Behera 7f6d942a81 serial: amba-pl011: Remove redundant label
The label 'out' is only used to return the error code. We can return the
error code directly and remove 'out' label.

Signed-off-by: Tushar Behera <tushar.b@samsung.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-09 17:13:54 -07:00
Peter Hurley ef8b9ddcb4 serial: Fix IGNBRK handling
If IGNBRK is set without either BRKINT or PARMRK set, some uart
drivers send a 0x00 byte for BREAK without the TTYBREAK flag to the
line discipline, when it should send either nothing or the TTYBREAK flag
set. This happens because the read_status_mask masks out the BI
condition, which uart_insert_char() then interprets as a normal 0x00 byte.

SUS v3 is clear regarding the meaning of IGNBRK; Section 11.2.2, General
Terminal Interface - Input Modes, states:
  "If IGNBRK is set, a break condition detected on input shall be ignored;
   that is, not put on the input queue and therefore not read by any
   process."

Fix read_status_mask to include the BI bit if IGNBRK is set; the
lsr status retains the BI bit if a BREAK is recv'd, which is
subsequently ignored in uart_insert_char() when masked with the
ignore_status_mask.

Affected drivers:
8250 - all
serial_txx9
mfd
amba-pl010
amba-pl011
atmel_serial
bfin_uart
dz
ip22zilog
max310x
mxs-auart
netx-serial
pnx8xxx_uart
pxa
sb1250-duart
sccnxp
serial_ks8695
sirfsoc_uart
st-asc
vr41xx_siu
zs
sunzilog
fsl_lpuart
sunsab
ucc_uart
bcm63xx_uart
sunsu
efm32-uart
pmac_zilog
mpsc
msm_serial
m32r_sio

Unaffected drivers:
omap-serial
rp2
sa1100
imx
icom

Annotated for fixes:
altera_uart
mcf

Drivers without break detection:
21285
xilinx-uartps
altera_jtaguart
apbuart
arc-uart
clps711x
max3100
uartlite
msm_serial_hs
nwpserial
lantiq
vt8500_serial

Unknown:
samsung
mpc52xx_uart
bfin_sport_uart
cpm_uart/core

Fixes: Bugzilla #71651, '8250_core.c incorrectly handles IGNBRK flag'
Reported-by: Ivan <athlon_@mail.ru>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-06-19 13:04:52 -07:00
Rob Herring 45e0f0f568 tty/serial: pl011: add DT based earlycon support
Enable DT based earlycon initialization for the pl011 uart.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Acked-by: Grant Likely <grant.likely@linaro.org>
2014-05-20 15:19:26 -05:00
Rob Herring 0d3c673e78 tty/serial: pl011: add generic earlycon support
Add earlycon support for the pl011 serial port. This allows enabling
the pl011 for console when early_params are processed. This is based
on the arm64 earlyprintk support and is intended to replace it.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-04-24 16:32:27 -07:00
Guennadi Liakhovetski 1e7da05304 serial: amba-pl011: fix regression, causing an Oops on rmmod
A recent commit ef2889f7ff "serial: pl011:
Move uart_register_driver call to device probe" introduced a regression,
causing the pl011 driver to Oops if more than 1 port have been probed. Fix
the Oops by only calling uart_unregister_driver() once after the last port
has been removed.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-04-16 14:31:13 -07:00
Guennadi Liakhovetski b2aeb775f8 serial: pl011: change Rx burst size to half of trigger level
The amba-pl011.c driver sets DMA burst size equal to FIFO trigger level.
If now exactly DMA burst size bytes are received, the DMAC will retrieve
them all and no Rx timeout interrupt will be generated. To fix that set
the burst size to half the FIFO trigger level.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-04-16 14:17:44 -07:00
Tushar Behera ef2889f7ff serial: pl011: Move uart_register_driver call to device probe
uart_register_driver call binds the driver to a specific device
node through tty_register_driver call. This should typically happen
during device probe call.

In a multiplatform scenario, it is possible that multiple serial
drivers are part of the kernel. Currently the driver registration fails
if multiple serial drivers with same default major/minor numbers are
included in the kernel.

A typical case is observed with amba-pl011 and samsung-uart drivers.

Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-02-13 10:33:00 -08:00
Guennadi Liakhovetski c25a1ad707 serial: pl011: fix fall back from DMA to interrupt mode
When falling back from DMA to interrupt mode the receive interrupt has to
be re-enabled to catch new incoming data.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-17 09:36:23 -08:00
Guennadi Liakhovetski 30ae585918 serial: pl011: (cosmetic) remove superfluous register write
In pl011_rx_chars() if pl011_dma_rx_trigger_dma() succeeds it will disable
the receive interrupt, no need to do this again.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-17 09:36:23 -08:00
Jon Medhurst 570d291048 serial: amba-pl011: preseserve hardware settings during initialisation
During initialisation, a UART may already be in use for a console, so
take care to preserve things like baud rate and data format to avoid
corrupting console output.

Signed-off-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-17 09:35:38 -08:00
Jon Medhurst b60f2f66a5 serial: amba-pl011: factor out code for writing LCR_H register
The code to cope with a split tx/rx LCR_H register is non-trivial
so put it into it's own function to avoid duplication.

Signed-off-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-17 09:35:37 -08:00
Jon Medhurst fe43390702 serial: amba-pl011: use port lock to guard control register access
When the pl011 is being used for a console, pl011_console_write forces
the control register (CR) to enable the UART for transmission and then
restores this to the original value afterwards. It does this while
holding the port lock.

Unfortunately, when the uart is started or shutdown - say in response to
userland using the serial device for a terminal - then this updates the
control register without any locking.

This means we can have

  pl011_console_write   Save CR
  pl011_startup         Initialise CR, e.g. enable receive
  pl011_console_write   Restore old CR with receive not enabled

this result is a serial port which doesn't respond to any input.

A similar race in reverse could happen when the device is shutdown.

We can fix these problems by taking the port lock when updating CR.

Signed-off-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-17 09:35:37 -08:00
Greg Kroah-Hartman 8f898bfd04 Revert "serial: pl011: use DMA RX polling by default"
This reverts commit 17438217a6 on request
of Linus Walleij:
	Greg can you please drop or revert
	commit 17438217a6
	"serial: pl011: use DMA RX polling by default"
	from the TTY tree until this has been sorted out?

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-17 09:33:18 -08:00
Linus Walleij 17438217a6 serial: pl011: use DMA RX polling by default
Making DMA RX polling optional when DMA is on was just
over-cautious: there is one single system in the kernel tree
using this facility, Ux500 and after some testing I turned
this on also for Ux500, which means it should simply be on
by default if DMA is enabled.

Cc: Jongsung Kim <neidhard.kim@lge.com>
Cc: Chanho Min <chanho.min@lge.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-08 17:09:07 -08:00
Ulf Hansson d0ce850d60 serial: pl011: Convert to modern PM ops
Convert to modern PM ops and use the SIMPLE_DEV_PM_OPS macro to set up
the PM callbacks.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-08 17:09:06 -08:00
Baruch Siach 187094feeb serial: pl011: remove redundant early amba_ports declaration
This early amba_ports declaration was introduced by commit c16d51a32 (amba
pl011: workaround for uart registers lockup) for use in the pl011_lockup_wa()
routine. This routine was later removed by commit 4fd0690bb (serial: pl011:
implement workaround for CTS clear event issue).

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-08 16:44:21 -08:00
Michal Simek 7ea816a0c3 serial: Remove unnecessary amba_set_drvdata()
Driver core clears the driver data to NULL after device_release
or on probe failure, so just remove it from here.

Driver core change:
"device-core: Ensure drvdata = NULL when no driver is bound"
(sha1: 0998d06310)

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-10-03 16:09:47 -07:00
Fabio Estevam b83286bfa8 serial: amba-pl011: Use __releases/__acquires annotations
Fix the following sparse warnings:

drivers/tty/serial/amba-pl011.c:687:20: warning: context imbalance in 'pl011_dma_flush_buffer' - unexpected unlock
drivers/tty/serial/amba-pl011.c:1200:13: warning: context imbalance in 'pl011_rx_chars' - unexpected unlock

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-08-12 11:37:48 -07:00
Jingoo Han 574de559c1 serial: use dev_get_platdata()
Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-31 17:56:15 -07:00
Linus Torvalds 3dbde57ad9 Pin control changes for the v3.11 kernel cycle:
- A large slew of improvements of the Genric pin configuration
   support, and deployment in four different platforms:
   Rockchip, Super-H PFC, ABx500 and TZ1090. Support BIAS_BUS_HOLD,
   get device tree parsing and debugfs support into shape.
 
 - We also have device tree support with generic naming conventions
   for the generic pin configuration.
 
 - Delete the unused and confusing direct pinconf API. Now state
   transitions is *the* way to control pins and multiplexing.
 
 - New drivers for Rockchip, TZ1090, and TZ1090 PDC.
 
 - Two pin control states related to power management are now
   handled in the device core: "sleep" and "idle", removing a lot
   of boilerplate code in drivers. We do not yet know if this is
   the final word for pin PM, but it already make things a lot
   easier to handle.
 
 - Handle sparse GPIO ranges passing a list of disparate pins, and
   utilize these in the new BayTrail (x86 Atom SoC) driver.
 
 - Make the sunxi (AllWinner) driver handle external interrupts.
 
 - Make it possible for pinctrl-single to handle the case where
   several pins are managed by a single register, and augment it to
   handle sleep modes.
 
 - Cleanups and improvements for the abx500 drivers.
 
 - Move Sirf pin control drivers to their own directory, support
   save/restore of context and add support for the SiRFatlas6 SoC.
 
 - PMU muxing for the Dove pinctrl driver.
 
 - Finalization and support for VF610 in the i.MX6 pinctrl driver.
 
 - Smoothen out various Exynos rough edges.
 
 - Generic cleanups of various kinds.
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Merge tag 'pinctrl-for-v3.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl

Pull pin control changes from Linus Walleij:

 - A large slew of improvements of the Genric pin configuration support,
   and deployment in four different platforms: Rockchip, Super-H PFC,
   ABx500 and TZ1090.  Support BIAS_BUS_HOLD, get device tree parsing
   and debugfs support into shape.

 - We also have device tree support with generic naming conventions for
   the generic pin configuration.

 - Delete the unused and confusing direct pinconf API.  Now state
   transitions is *the* way to control pins and multiplexing.

 - New drivers for Rockchip, TZ1090, and TZ1090 PDC.

 - Two pin control states related to power management are now handled in
   the device core: "sleep" and "idle", removing a lot of boilerplate
   code in drivers.  We do not yet know if this is the final word for
   pin PM, but it already make things a lot easier to handle.

 - Handle sparse GPIO ranges passing a list of disparate pins, and
   utilize these in the new BayTrail (x86 Atom SoC) driver.

 - Make the sunxi (AllWinner) driver handle external interrupts.

 - Make it possible for pinctrl-single to handle the case where several
   pins are managed by a single register, and augment it to handle sleep
   modes.

 - Cleanups and improvements for the abx500 drivers.

 - Move Sirf pin control drivers to their own directory, support
   save/restore of context and add support for the SiRFatlas6 SoC.

 - PMU muxing for the Dove pinctrl driver.

 - Finalization and support for VF610 in the i.MX6 pinctrl driver.

 - Smoothen out various Exynos rough edges.

 - Generic cleanups of various kinds.

* tag 'pinctrl-for-v3.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (82 commits)
  pinctrl: vt8500: wmt: remove redundant dev_err call in wmt_pinctrl_probe()
  pinctrl: remove bindings for pinconf options needing more thought
  pinctrl: remove slew-rate parameter from tz1090
  pinctrl: set unit for debounce time pinconfig to usec
  pinctrl: more clarifications for generic pull configs
  pinctrl: rip out the direct pinconf API
  pinctrl-tz1090-pdc: add TZ1090 PDC pinctrl driver
  pinctrl-tz1090: add TZ1090 pinctrl driver
  pinctrl: samsung: Staticize drvdata_list
  pinctrl: rockchip: Add missing irq_gc_unlock() call before return error
  pinctrl: abx500: rework error path
  pinctrl: abx500: suppress hardcoded value
  pinctrl: abx500: factorize code
  pinctrl: abx500: fix abx500_gpio_get()
  pinctrl: abx500: fix abx500_pin_config_set()
  pinctrl: abx500: Add device tree support
  sh-pfc: Guard DT parsing with #ifdef CONFIG_OF
  pinctrl: add Intel BayTrail GPIO/pinctrl support
  pinctrl: fix pinconf_ops::pin_config_dbg_parse_modify kerneldoc
  pinctrl: Staticize local symbols
  ...

Conflicts:
	drivers/net/ethernet/ti/davinci_mdio.c
	drivers/pinctrl/Makefile
2013-07-03 11:48:03 -07:00
Linus Walleij 2b996fc500 tty: serial: modify PL011 driver to use pinctrl PM helpers
This augments the PL011 UART driver to utilize the new pinctrl
core PM helpers to transition the driver to default and sleep
states, cutting away some boilerplate code.

Cc: Hebbar Gururaja <gururaja.hebbar@ti.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2013-06-16 11:56:52 +02:00
Greg Kroah-Hartman 8095e4e81b Merge 3.10-rc3 into tty-next
We want these fixes.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-05-27 10:57:53 +09:00