The following drivers: 8250_core, atmel_serial, max310x, mcf, omap-serial
and sci16is7xx implement code to handle RS485 ioctls.
In order to avoid code duplication, we implement a simple ioctl handler
on the serial_core layer.
This handler can be used by all the other drivers instead of duplicating
code.
Until this is the only RS485 ioctl handler, it will try first the
rs485_config callback and if it is not present it will call the driver
specific ioctl.
Peter Hurley [Wed, 5 Nov 2014 18:11:45 +0000 (13:11 -0500)]
serial: Test/disable MSIs if switching from N_PPS
Switching to the N_PPS line discipline may require enabling
modem status interrupts; conversely switching from N_PPS may
require disabling modem status interrupts.
Affected drivers:
8250
amba-pl010
atmel
Cc: Nicolas Ferre <nicolas.ferre@atmel.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>
Peter Hurley [Wed, 5 Nov 2014 18:11:43 +0000 (13:11 -0500)]
serial: core: Pass termios to set_ldisc() notifications
UART drivers which enable modem status interrupts when switching
to N_PPS line discipline need to determine if modem status
interrupts should be disabled when switching from N_PPS.
Specifically, the set_ldisc() notification needs to evaluate
UART_ENABLE_MS() which requires termios->c_cflag.
Convert in-tree UART drivers to new interface.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Wed, 5 Nov 2014 18:11:42 +0000 (13:11 -0500)]
serial: core: Claim port mutex for set_ldisc()
Three UART drivers (8250, atmel & amba-pl010) enable modem status
interrupts if the line discipline is changed to N_PPS. However,
the uart port flags may only be safely modified while holding the
port mutex.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Wed, 5 Nov 2014 18:11:41 +0000 (13:11 -0500)]
tty: Allow safe access to termios for set_ldisc() handlers
Allow a tty driver to safely access termios settings while handling
the set_ldisc() notification. UART drivers use the set_ldisc()
notification to check if the N_PPS line discipline is being enabled;
if so, modem status interrupts may also need to be enabled. Conversely,
modem status interrupts may need to be disabled if switching away
from the N_PPS line discipline.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Wed, 5 Nov 2014 17:40:05 +0000 (12:40 -0500)]
tty: Flush tty buffers after hardware shutdown
The line discipline buffer and the tty buffers must be flushed again
after hardware shutdown; otherwise, a brief window exists between the
ldisc flush in tty_port_close_start() and the subsequent
tty_port_shutdown(), during which more data could be received into the
tty buffers. A racing open might then be able to receive data from the
previous session.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Julien CHAUVEAU [Tue, 4 Nov 2014 10:45:55 +0000 (11:45 +0100)]
serial: 8250_dw: get index of serial line from DT aliases
Get index of serial line from device tree using function of_alias_get_id().
If no alias is found, the 8250 core takes care of incrementing the line number.
Lucas Stach [Mon, 3 Nov 2014 22:16:54 +0000 (23:16 +0100)]
serial: of-serial: fetch line number from DT
The general agreed way to specify a fixed line number
for a serial console is to provide a "serial" alias
in the devicetree. Start parsing this property in
of_serial.
Signed-off-by: Lucas Stach <dev@lynxeye.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Several init/setup functions passed the PCI BAR resource start address
to ioremap_nocache() via an unsigned long. This caused address truncation
for a 32-bit device mapped above 4 GiB (i.e. the CPU interacts with the
device via a translated address), which resulted in a kernel panic.
This patch replaces all of the instances of intermediate variable use
with pci_ioremap_bar() to ensure the full resource_size_t start address
is used and that ioremap_nocache() is still called.
The kernel panic (Exar XR17V358 PCIe device on a Freescale P2020 SBC):
In mtk8250_set_termios function, calculating quot value can not be zero,
otherwise, using DIV_ROUND_CLOSEST(port->uartclk, quot * baud) will fail due to
divisor is zero.
Signed-off-by: Eddie Huang <eddie.huang@mediatek.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We don't really need to perform the ioremap "on demand" so it's simpler
just to do it from the probe function. This also lets us eliminate the
UART_REG_SIZE constant and rely on the resource information passed in
from the DT or platform code.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Kevin Cernekee [Tue, 21 Oct 2014 22:23:02 +0000 (15:23 -0700)]
tty: serial: bcm63xx: Enable DT earlycon support
This enables early console output if there is a chosen/stdout-path
property referencing a UART node with the "brcm,bcm6345-uart" compatible
string. The bootloader sets up the pinmux and baud/parity/etc.
Tested on bcm3384 (MIPS, DT).
Signed-off-by: Kevin Cernekee <cernekee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Kevin Cernekee [Tue, 21 Oct 2014 22:22:58 +0000 (15:22 -0700)]
tty: serial: bcm63xx: Add support for unnamed clock outputs from DT
The original non-DT bcm63xx clk code ignores the struct device argument
and looks up a global clock name. DT platforms, by contrast, often just
use a phandle to reference a clock node with no "clock-output-names"
property. Modify the UART driver to support both schemes.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Kevin Cernekee [Tue, 21 Oct 2014 22:22:57 +0000 (15:22 -0700)]
tty: serial: bcm63xx: Allow bcm63xx_uart to be built on other platforms
This device was originally supported on bcm63xx only, but it shows up on
a wide variety of MIPS and ARM chipsets spanning multiple product lines.
Now that the driver has eliminated dependencies on bcm63xx-specific
header files, we can build it on any non-bcm63xx kernel.
Compile-tested on x86, both statically and as a module. Tested for
functionality on bcm3384 (a new MIPS platform under active development).
Daniel Thompson [Tue, 28 Oct 2014 08:28:07 +0000 (09:28 +0100)]
serial: imx: clean up imx_poll_put_char()
imx_put_poll_char() has been simplified to remove the code to disable
interrupts. The present code can corrupt register state when re-entered
from FIQ handler.
Switch to _relaxed() MMIO functions (which are safe for polled I/O and
needed to avoid taking spin locks).
Stephen Boyd [Thu, 23 Oct 2014 00:33:01 +0000 (17:33 -0700)]
tty: serial: msm_serial: Use DT aliases
We rely on probe order of this driver to determine the line number for
the uart port. This makes it impossible to know the line number
when these devices are populated via DT. Use the DT alias
mechanism to assign the line based on the aliases node.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stephen Boyd [Thu, 30 Oct 2014 01:47:01 +0000 (18:47 -0700)]
tty: serial: msm: Reset uartdm after baud rate change
We need to issue a reset if we ever change the value of the IPR
register on DM hardware. If we don't reset the hardware the RX
stale interrupt never triggers and the only way to trigger an RX
handling event is by filling up the fifo. This causes things like
getty to not work so well considering it might change the baud
rate a few times. Fix this by moving the reset on startup and any
reprogramming required after the reset to be after we change the
baud rate.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stephen Boyd [Wed, 29 Oct 2014 18:14:38 +0000 (11:14 -0700)]
tty: serial: msm: Support sysrq on uartDM devices
To properly support sysrq on uartDM hardware we need to properly
handle break characters. With the DM hardware the fifo can pack 4
characters at a time, where a break is indicated by an all zero
byte. Unfortunately, we can't differentiate between an all zero
byte for a break and an all zero byte of data, so try and do as
best we can. First unmask the RX break start interrupt and record
the interrupt when it arrives. Then while processing the fifo,
detect the break by searching for an all zero character as long
as we recently received an RX break start interrupt. This should
make sysrq work fairly well.
Cc: Frank Rowand <frank.rowand@sonymobile.com> Cc: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stephen Boyd [Wed, 29 Oct 2014 18:14:37 +0000 (11:14 -0700)]
tty: serial: msm: Fix sysrq spinlock recursion on non-DM
The handle_rx() path calls uart_handle_sysrq_char() with the port
lock held. This causes a spinlock recursion. Release and
reacquire the lock here to avoid this.
Janusz Uzycki [Fri, 10 Oct 2014 16:53:24 +0000 (18:53 +0200)]
serial: mxs-auart: clean get_mctrl and set_mctrl
Russell King:
The only thing which the .get_mctrl method is supposed to do is
to return the state of the /input/ lines, which are CTS, DCD, DSR, RI.
The output line state is stored in port->mctrl, and is added to
the returned value by serial_core when it's required.
RTS output state should not be returned from the .get_mctrl method.
This patch removes ctrl variable from mxs_auart_port
and removes useless reading back RTS line.
The ctrl variable in mxs_auart_port duplicated mctrl,
member of uart_port structure in serial_core.h.
The removed code from mxs_auart_set_mctrl() and mxs_auart_get_mctrl
duplicated uart_update_mctrl() and uart_tiocmget()
in serial_core.c.
Signed-off-by: Janusz Uzycki <j.uzycki@elproma.com.pl> Reviewed-by: Richard Genoud <richard.genoud@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cyrille Pitchen [Mon, 20 Oct 2014 17:12:20 +0000 (19:12 +0200)]
tty/serial: at91: fix rx ring buffer management
This patch swaps the use "tail" and "head" to fit the semantic of the linux
circular buffer documentation:
- head: the point at which the producer (the DMA controller) inserts items.
- tail: the point at which the consumer (the serial framework) finds the next
item.
Besides the former code of the rx ring buffer didn't manage the case where
head < tail, which might lead to loss of data. To fix this bug the data are now
sent from the DMA buffer to the serial framework in two steps:
1 - First, we test if head < tail. If so, we copy the data from tail to the end
of the DMA buffer then reset tail to zero.
2 - Finally, we copy data from tail to head then set tail to head.
In addition, since tty_insert_flip_string() may now be called twice,
atmel_flip_buffer_rx_dma() becomes less efficient than moving the calls
dma_sync_sg_for_cpu(), dma_sync_sg_for_device(), tty_insert_flip_string() and
tty_flip_buffer_push() directly into atmel_rx_from_dma().
John Crispin [Thu, 16 Oct 2014 19:48:21 +0000 (21:48 +0200)]
serial: of: add a PORT_RT2880 definition
The Ralink RT2880 SoC and its successors have an internal 8250 core. This core
needs the same quirks applied as the AMD AU1xxx uart. In addition to these
quirks, the ports memory region is only 0x100 unlike the AU1xxx which has a
size of 0x1000.
Signed-off-by: John Crispin <blogic@openwrt.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Nishanth Menon [Wed, 22 Oct 2014 12:46:50 +0000 (07:46 -0500)]
tty: serial: omap: Increase max consoles and add check to prevent crash
Increase the maximum number of consoles possible to 10 since DRA7 now
has the maximum number of consoles possible. without doing this, for
example, enabling DRA7 UART10 results in internal data structures and
console cannot match up and we endup with a crash as follows:
The final solution is to transition off to use 8250 driver and no
dependency on console structures and move away from omap-serial
driver, hence no major cleanups are done for this driver, so add a
simple check to prevent future crashes in a similar manner in case of
platform with additional ports.
Signed-off-by: Nishanth Menon <nm@ti.com> Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Thu, 6 Nov 2014 14:06:12 +0000 (09:06 -0500)]
serial: pl011: Fix build breakage with !CONFIG_DMA_ENGINE
Commit 479e9b94fdce7bc4 ("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>
Peter Hurley [Wed, 5 Nov 2014 17:26:31 +0000 (12:26 -0500)]
vt: Remove vt_get_kmsg_redirect() from uapi header
vt_get_kmsg_redirect() only has meaning to the console driver as
an alias for calling vt_kmsg_redirect(). Move the macro definition
to the only source file which uses it; remove from uapi/linux/vt.h
Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Wed, 5 Nov 2014 17:26:30 +0000 (12:26 -0500)]
tty: Document defunct ASYNC_SPLIT_TERMIOS flag in uapi header
The last vestige of ASYNC_SPLIT_TERMIOS was removed by commit
'cris: Remove obsolete ASYNC_SPLIT_TERMIOS behavior'. Mark the flag
as defunct in the uapi header.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial_console_init() is not defined by the tty core; remove
declaration.
Note that the powerpc arch boot code contains a serial_console_init()
declaration in arch/powerpc/boot/ops.h which is restricted to
the powerpc arch boot.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
,which misses printing the associated device address.
In order to fix this, register all the irqs inside the probe function via
devm_request_irq(), which will correctly report the serial interrupts associated
with their correspondent serial device and also helps simplyfing the code by
avoiding the calls to free_irq().
Commit e676253b19b2 ("serial/8250: Add support for RS485 IOCTLs") added
references to TIOC[SG]RS48 on 8250_core.c. This change triggered the
need to define them in all the arches that uses tty/serial.
Commit e676253b19b2 ("serial/8250: Add support for RS485 IOCTLs") added
references to TIOC[SG]RS48 on 8250_core.c. This change triggered the
need to define them in all the arches that uses tty/serial.
Ray Jui [Wed, 8 Oct 2014 00:35:47 +0000 (17:35 -0700)]
serial: 8250_dw: Add DMA support for non-ACPI platforms
The dma pointer under struct uart_8250_port is currently left
unassigned for non-ACPI platforms. It should be pointing to the dma
member in struct dw8250_data like how it was done for ACPI, so the core
8250 code will try to request for DMA when registering the port
If DMA is not enabled in device tree, request DMA will fail and the
driver will fall back to PIO
Signed-off-by: Ray Jui <rjui@broadcom.com> Reviewed-by: JD (Jiandong) Zheng <jdzheng@broadcom.com> Reviewed-by: Scott Branden <sbranden@broadcom.com> Tested-by: Scott Branden <sbranden@broadcom.com> Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
max310x: max3109_detect should use indirect addressing in SPI mode for REVID register
This patch allows to read the REV_ID register in SPI mode and consequently
to properly detect the max3109. Indeed in SPI mode, this register is only
accessible by using indirect addressing.
Paul Bolle [Mon, 6 Oct 2014 10:07:23 +0000 (12:07 +0200)]
serial: samsung: Remove checks for CONFIG_SAMSUNG_CLOCK
Commit 32726d2d5502 ("ARM: SAMSUNG: Remove legacy clock code") removed
the Kconfig symbol SAMSUNG_CLOCK. Remove the last checks for its macro,
and the dead code they hide, too.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: use container_of to resolve uart_sunzilog_port from uart_port
Use container_of instead of casting first structure member.
Signed-off-by: Fabian Frederick <fabf@skynet.be> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: sunsab: use container_of to resolve uart_sunsu_port from uart_port
Use container_of instead of casting first structure member.
Signed-off-by: Fabian Frederick <fabf@skynet.be> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: sunsu: use container_of to resolve uart_sunsu_port from uart_port
Use container_of instead of casting first structure member.
Signed-off-by: Fabian Frederick <fabf@skynet.be> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch adds the required pieces to 8250-OMAP UART driver for DMA
support. The TX burst size is set to 1 so we can send an arbitrary
amount of bytes.
The RX burst is currently set to 48 which means we receive an DMA
interrupt every 48 bytes and have to reprogram everything. Less bytes in
the RX-FIFO mean that no DMA transfer will happen and the UART will send a
RX-timeout _or_ RDI event at which point the FIFO will be manually purged.
There is a workaround for TX-DMA on AM33xx where we put the first byte
into the FIFO to kick start the DMA process. Haven't seen this problem on
OMAP36xx (beagle board xm) or DRA7xx.
On AM375x there is "Usage Note 2.7: UART: Cannot Acknowledge Idle
Requests in Smartidle Mode When Configured for DMA Operations" in the
errata document. This problem persists even after disabling DMA in the
UART and will be addressed in the HWMOD.
v10:
- delay update_registers() from set_termios() until TX-DMA is
done. It has been reported / proved that invoking
update_registers() while TX-DMA is in progress may stall the
DMA operation and it won't finish.
- use the new omap DMA-TX-RX hooks and DMA only interrupt
routine.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We have (or will have) custom DMA callbacks in the omap driver due to
the different behaviour in the RX and TX case. To make this work
we need a few changes in the IRQ handler to invoke the rx_handler again
after the "manual" mode or retry the tx_handler again before falling
back to the manual mode.
Heikki didn't want to see the extra hacks in the generic / default irq
handler and Peter wasn't too happy about an OMAP-only IRQ handler. The
way I planned it is to use this extra IRQ routine only in DMA case. If
Peter dislike this approach then I hope Heikki doesn't block changes in
the default IRQ handler :)
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The omap needs a DMA request pending right away. If it is
enqueued once the bytes are in the FIFO then nothing will happen
and the FIFO will be later purged via RX-timeout interrupt.
This patch enqueues RX-DMA request on completion but not if it
was aborted on error. The first enqueue will happen in the driver
in startup.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch provides mostly a copy of serial8250_tx_dma() +
__dma_tx_complete() with the following extensions:
- DMA bug
At least on AM335x the following problem exists: Even if the TX FIFO is
empty and a TX transfer is programmed (and started) the UART does not
trigger the DMA transfer.
After $TRESHOLD number of bytes have been written to the FIFO manually the
UART reevaluates the whole situation and decides that now there is enough
room in the FIFO and so the transfer begins.
This problem has not been seen on DRA7 or beagle board xm (OMAP3). I am not
sure if this is UART-IP core specific or DMA engine.
The workaround is to use a threshold of one byte, program the DMA
transfer minus one byte and then to put the first byte into the FIFO to
kick start the transfer.
- support for runtime PM
RPM is enabled on start_tx(). We can't disable RPM on DMA complete callback
because there is still data in the FIFO which is being sent. We have to wait
until the FIFO is empty before we disable it.
For this to happen we fake a TX sent error and enable THRI. Once the
FIFO is empty we receive an interrupt and since the TTY-buffer is still
empty we "put RPM" via __stop_tx(). Should it been filed then in the
start_tx() path we should program the DMA transfer and remove the error
flag and the THRI bit.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty: serial: 8250: allow to use custom DMA implementation
The OMAP has a few corner cases where it needs a share of kindness of
affection to do the right thing. Heikki Krogerus suggested that instead
adding the quirks into the default DMA implementation, OMAP could get
its own copy of the function. And Alan suggested the same thing so here
we go.
This patch provides callbacks for custom TX/RX DMA implementation. If
there are not setup / used, then the default (current) implementation is
used.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty: serial: 8250_dma: keep own book keeping about RX transfers
After dmaengine_terminate_all() has been invoked then both DMA drivers
(edma and omap-dma) do not invoke dma_cookie_complete() to mark the
transfer as complete. This dma_cookie_complete() is performed by the
Synopsys DesignWare driver which is probably the only one that is used
by omap8250-dma and hence don't see following problem…
…which is that once a RX transfer has been terminated then following
query of channel status reports DMA_IN_PROGRESS (again: the actual
transfer has been canceled, there is nothing going on anymore).
This means that serial8250_rx_dma() never enqueues another DMA transfer
because it (wrongly) assumes that there is a transer already pending.
Vinod Koul refuses to accept a patch which adds this
dma_cookie_complete() to both drivers and so dmaengine_tx_status() would
report DMA_COMPLETE instead (and behave like the Synopsys DesignWare
driver already does). He argues that I am not allowed to use the cookie
to query the status and that the driver already cleaned everything up after
the invokation of dmaengine_terminate_all().
To end this I add a bookkeeping whether or not a RX-transfer has been
started to the 8250-dma code. It has already been done for the TX side.
*Now* we learn about the RX status based on our bookkeeping and don't
need dmaengine_tx_status() for this anymore.
Cc: vinod.koul@intel.com Reviewed-by: Tony Lindgren <tony@atomide.com> Tested-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Right now it is possible that serial8250_tx_dma() fails and returns
-EBUSY. The caller (serial8250_start_tx()) will then enable
UART_IER_THRI which will generate an interrupt once the TX FIFO is
empty.
In serial8250_handle_irq() nothing will happen because up->dma is set
and so serial8250_tx_chars() won't be invoked. We end up with plenty of
interrupts and some "too much work for irq" output.
This patch introduces dma_tx_err in struct uart_8250_port to signal that
the last invocation of serial8250_tx_dma() failed so we can fill the TX
FIFO manually. Should the next invocation of serial8250_start_tx()
succeed then the dma_tx_err flag along with the THRI bit is removed and
DMA only usage may continue.
Reviewed-by: Tony Lindgren <tony@atomide.com> Tested-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch provides a 8250-core based UART driver for the internal OMAP
UART. The long term goal is to provide the same functionality as the
current OMAP uart driver and DMA support.
I tried to merge omap-serial code together with the 8250-core code.
There should should be hardly a noticable difference. The trigger levels
are different compared to omap-serial:
- omap serial
TX: Interrupt comes after TX FIFO has room for 16 bytes.
TX of 4096 bytes in one go results in 256 interrupts
RX: Interrupt comes after there is on byte in the FIFO.
RX of 4096 bytes results in 4096 interrupts.
- this driver
TX: Interrupt comes once the TX FIFO is empty.
TX of 4096 bytes results in 65 interrupts. That means there will
be gaps on the line while the driver reloads the FIFO.
RX: Interrupt comes once there are 48 bytes in the FIFO or less over
"longer" time frame. We have
1 / 11520 * 10^3 * 16 => 1.38… ms
1.38ms to react and purge the FIFO on 115200,8N1. Since the other
driver fired after each byte it had ~5.47ms time to react. This
_may_ cause problems if one relies on no missing bytes and has no
flow control. On the other hand we get only 85 interrupts for the
same amount of data.
It has been only tested as console UART on am335x-evm, dra7-evm and
beagle bone. I also did some longer raw-transfers to meassure the load.
The device name is ttyS based instead of ttyO. If a ttyO based node name
is required please ask udev for it. If both driver are activated (this
and omap-serial) then this serial driver will take control over the
device due to the link order
v9…v10:
- Tony noticed that omap3 won't show anything after waking up
from core off. In v9 I reworked the register restore and set
IER to 0 by accident. This went unnoticed because start_tx
usually sets ier (either due to DMA bug or due to TX-complete
IRQ).
- dropped EFR and SLEEP from capabilities. We do have both but
nobody should touch it. We already handle SLEEP ourself.
- make the private copy of the registers (like EFR) u8 instead
u32
- drop MDR1 & DL[ML] reset in restore registers. Does not look
required it is set to the required value later.
- update MDR1 & SCR only if changed.
- set MDR1 as the last thing. The errata says that we should
setup everything before MDR1 set.
- avoid div by 0 in omap_8250_get_divisor() if baud rate gets
very large (Frans Klaver fixed the same thing omap-serial)
- drop "is in early stage" from Kconfig.
v8…v9:
- less on a file seems to hang the am335x after a while. I
believe I introduce this bug a while ago since I can reproduce
this prior to v8. Fixed by redoing the omap8250_restore_regs()
v7…v8:
- redo the register write. There is now one function for that
which is used from set_termios() and runtime-resume.
- drop PORT_OMAP_16750 and move the setup to the omap file. We
have our own set termios function anyway (Heikki Krogerus)
- use MEM instead of MEM32. TRM of AM/DM37x says that 32bit
access on THR might result in data abort. We only need 32bit
access in the errata function which is before we use 8250's
read function so it doesn't matter.
v4…v7:
- change trigger levels after some tests with raw transfers.
v3…v4:
- drop RS485 support
- wire up ->throttle / ->unthrottle
v2…v3:
- wire up startup & shutdown for wakeup-irq handling.
- RS485 handling (well the core does).
v1…v2:
- added runtime PM. Could somebody could please double check
this?
- added omap_8250_set_termios()
Reviewed-by: Tony Lindgren <tony@atomide.com> Tested-by: Tony Lindgren <tony@atomide.com> Tested-by: Frans Klaver <frans.klaver@xsens.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty: serial: 8250: make serial8250_console_setup() non _init
if I boot with console=ttyS0 and the omap driver is module I end up with
| console [ttyS0] disabled
| omap8250 44e09000.serial: ttyS0 at MMIO 0x44e09000 (irq = 88, base_baud = 3000000) is a 8250
| Unable to handle kernel paging request at virtual address c07a9de0
| Modules linked in: 8250_omap(+)
| CPU: 0 PID: 908 Comm: modprobe Not tainted 3.17.0-rc5+ #1593
| PC is at serial8250_console_setup+0x0/0xc8
| LR is at register_console+0x13c/0x3a4
| [<c0078788>] (register_console) from [<c02d0340>] (uart_add_one_port+0x3cc/0x420)
| [<c02d0340>] (uart_add_one_port) from [<c02d38a4>] (serial8250_register_8250_port+0x298/0x39c)
| [<c02d38a4>] (serial8250_register_8250_port) from [<bf006274>] (omap8250_probe+0x218/0x3dc [8250_omap])
| [<bf006274>] (omap8250_probe [8250_omap]) from [<c02e3424>] (platform_drv_probe+0x2c/0x5c)
| [<c02e3424>] (platform_drv_probe) from [<c02e1eac>] (driver_probe_device+0x104/0x228)
…
| [<c009fa48>] (SyS_init_module) from [<c000e6e0>] (ret_fast_syscall+0x0/0x30)
| Code: 7823603bf8314620051b3013491ed416 (44792204)
because serial8250_console_setup() is already gone.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
projects / mirror_ubuntu-hirsute-kernel.git / log