The two callers to serial_out_sync() have a struct port right
there in scope, but then pass in a struct 8250_port which then
is locally resolved back to a struct port.
Delete the needless back and forth and just pass in the struct
port directly. Rename the function to have "_port" in its
name, so the name <--> args relationship is consistent with the
other serial_in/out vs serial_port_in/out function classes.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The serial_in and serial_out helpers are expecting to operate
on an 8250_port struct. These in turn go after the contained
normal port struct which actually has the actual in/out accessors.
But what is happening in some cases, is that a function is passed
in a port struct, and it runs container_of to get the 8250_port
struct, and then it uses serial_in/out helpers on that. But when
you do, it goes full circle, since it jumps back inside the 8250_port
to find the contained port struct (which we already knew!).
So, if we are operating in a scope where we know the struct port,
then use the serial_port_in/out helpers and avoid the bouncing
around. If we don't have the struct port handy, and it isn't
worth making a local for it, then just leave things as-is which
uses the serial_in/out helpers that will resolve the 8250_port
onto the struct port.
Mostly, gcc figures this out on its own -- so this doesn't bring to
the table any revolutionary runtime delta. However, it is somewhat
misleading to always hammer away on 8250 structs, when the actual
underlying property isn't at all 8250 specific -- and this change
makes that clear.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The serial_8250_port struct contains within a serial_port struct
and many times one or the other, or both are in scope within
functions via a passed in arg, or via container_of.
However there are a lot of cases where we have access directly
to the port pointer, but yet go through the parent 8250_port
structure instead to get it. These should just use the port
struct directly.
Similarly there are cases where it makes sense (from a code
cleanliness point of view) to declare a local for the port
struct, so we aren't going through the parent 8250_port struct
repeatedly to get to it.
We get a small reduction in text size, but it appears that
gcc was smart enough to internally be doing most of this
already, so the readability improvement is the larger gain.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
These might have worked some magic with an ancient gcc back in
1992, but "objdump --disassemble" on gcc 4.6 on x86-64 shows
identical output before and after this commit. Send the casts
and their hysterical rasins to the bitbucket.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently 8250.c has serial_in and serial_out as shortcuts
to doing the port I/O. They are implemented as macros a
ways down in the file. This isn't by accident, but is
implicitly required, so cpp doesn't mangle other instances
of the common string "serial_in", as it exists as a field
in the port struct itself.
The above mangling avoidance violates the principle of least
surprise, and it also prevents the shortcuts from being
relocated up to the top of file, or into 8250.h -- either
being a better location than the current one.
Move them to 8250.h so other 8250-like drivers can also use
the shortcuts, and in the process, make the conflicting
names go away by using static inlines instead of macros.
The object file size remains unchanged with this modification.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is the last traces of pausing I/O that we had back some
twenty years ago. Probably was only required for 8MHz ISA
cards running "on the edge" at 12MHz. Anyway it hasn't been
in use for years, so lets just bury it for good.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Rather than hardcode 9600, use the existing default_baud parameter (which
also defaults to 9600).
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
CC: Tomoya MORINAGA <tomoya.rohm@gmail.com>
CC: Feng Tang <feng.tang@intel.com>
CC: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For cases where boards with non-default clocks are not yet added to the kernel
or when the clock varies across hardware revisions, it is useful to be
able to specify the UART clock on the kernel command line.
Add the user_uartclk parameter and prefer it, if set, to the default and
board specific UART clock settings. Specify user_uartclock on the command-line
with "pch_uart.user_uartclk=48000000".
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
CC: Tomoya MORINAGA <tomoya.rohm@gmail.com>
CC: Feng Tang <feng.tang@intel.com>
CC: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add support for the Fish River Island II (FRI2) UART clock following the CM-iTC
quirk handling mechanism. Depending on the firmware installed on the device, the
FRI2 uses a 48MHz or a 64MHz UART clock. This is detected with DMI strings.
Add similar UART clock quirk handling to the pch_console_setup() function to
enable kernel messages on boards with non-standard UART clocks.
Per Alan's suggestion, abstract out UART clock selection into
pch_uart_get_uartclk() to avoid code duplication.
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
CC: Tomoya MORINAGA <tomoya.rohm@gmail.com>
CC: Feng Tang <feng.tang@intel.com>
CC: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The term "base baud" refers to the fastest baud rate the device can communicate
at. This is clock/16. pch_uart is using base_baud as the clock itself. Rename
the variables to be semantically correct.
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
CC: Tomoya MORINAGA <tomoya.rohm@gmail.com>
CC: Feng Tang <feng.tang@intel.com>
CC: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In addition to the /32 prescaler, the MPC5200B supports a second
baudrate prescaler /4 to reach higher baudrates.
The current calculation (introduced with commit 0d1f22e4) in the kernel
preferes this low prescaler as often as possible, but with some
imprecise counterparts the communication on low baudrates fails.
According a support-mail from freescale the low prescaler (/4) allows
just 1% tolerance in bittiming in contrast to 4% of the high prescaler
(/32). The prescaler not only affects the baudrate-calculation, but
also the sampling of the bits on the wire.
With this patch, we use the slightly less precise, but higher tolerant
prescaler calculation on low baudrates up to (and including) 115200 baud
and the more precise calculation above.
Tested on a custom MPC5200B board with "fsl,mpc5200b-psc-uart".
Calculation Examples with prescaler (PS) 4 and 32 and divisor (DIV) on
various baudrates. Real stands for the real baudrate generated and Diff
for the differences between:
50 Baud PS 32 DIV 0xa122 Real 50 Diff 0.00%
75 Baud PS 32 DIV 0x6b6c Real 75 Diff 0.00%
110 Baud PS 32 DIV 0x493e Real 110 Diff 0.00%
134 Baud PS 32 DIV 0x3c20 Real 133 Diff 0.75%
150 Baud PS 32 DIV 0x35b6 Real 150 Diff 0.00%
200 Baud PS 32 DIV 0x2849 Real 199 Diff 0.50%
300 Baud PS 4 DIV 0xd6d8 Real 300 Diff 0.00%
PS 32 DIV 0x1adb Real 300 Diff 0.00%
600 Baud PS 4 DIV 0x6b6c Real 600 Diff 0.00%
PS 32 DIV 0x0d6e Real 599 Diff 0.17%
1200 Baud PS 4 DIV 0x35b6 Real 1200 Diff 0.00%
PS 32 DIV 0x06b7 Real 1199 Diff 0.08%
1800 Baud PS 4 DIV 0x23cf Real 1799 Diff 0.06%
PS 32 DIV 0x047a Real 1799 Diff 0.06%
2400 Baud PS 4 DIV 0x1adb Real 2400 Diff 0.00%
PS 32 DIV 0x035b Real 2401 Diff - 0.04%
4800 Baud PS 4 DIV 0x0d6e Real 4799 Diff 0.02%
PS 32 DIV 0x01ae Real 4796 Diff 0.08%
9600 Baud PS 4 DIV 0x06b7 Real 9598 Diff 0.02%
PS 32 DIV 0x00d7 Real 9593 Diff 0.07%
19200 Baud PS 4 DIV 0x035b Real 19208 Diff - 0.04%
PS 32 DIV 0x006b Real 19275 Diff - 0.39%
38400 Baud PS 4 DIV 0x01ae Real 38372 Diff 0.07%
PS 32 DIV 0x0036 Real 38194 Diff 0.54%
57600 Baud PS 4 DIV 0x011e Real 57692 Diff - 0.16%
PS 32 DIV 0x0024 Real 57291 Diff 0.54%
76800 Baud PS 4 DIV 0x00d7 Real 76744 Diff 0.07%
PS 32 DIV 0x001b Real 76388 Diff 0.54%
115200 Baud PS 4 DIV 0x008f Real 115384 Diff - 0.16%
PS 32 DIV 0x0012 Real 114583 Diff 0.54%
153600 Baud PS 4 DIV 0x006b Real 154205 Diff - 0.39%
PS 32 DIV 0x000d Real 158653 Diff - 3.29%
230400 Baud PS 4 DIV 0x0048 Real 229166 Diff 0.54%
PS 32 DIV 0x0009 Real 229166 Diff 0.54%
307200 Baud PS 4 DIV 0x0036 Real 305555 Diff 0.54%
PS 32 DIV 0x0007 Real 294642 Diff 4.09%
460800 Baud PS 4 DIV 0x0024 Real 458333 Diff 0.54%
PS 32 DIV 0x0005 Real 412500 Diff 10.48%
500000 Baud PS 4 DIV 0x0021 Real 500000 Diff 0.00%
PS 32 DIV 0x0004 Real 515625 Diff - 3.13%
576000 Baud PS 4 DIV 0x001d Real 568965 Diff 1.22%
PS 32 DIV 0x0004 Real 515625 Diff 10.48%
614400 Baud PS 4 DIV 0x001b Real 611111 Diff 0.54%
PS 32 DIV 0x0003 Real 687500 Diff -11.90%
921600 Baud PS 4 DIV 0x0012 Real 916666 Diff 0.54%
PS 32 DIV 0x0002 Real 1031250 Diff -11.90%
1000000 Baud PS 4 DIV 0x0011 Real 970588 Diff 2.94%
PS 32 DIV 0x0002 Real 1031250 Diff - 3.13%
1152000 Baud PS 4 DIV 0x000e Real 1178571 Diff - 2.31%
PS 32 DIV 0x0002 Real 1031250 Diff 10.48%
1500000 Baud PS 4 DIV 0x000b Real 1500000 Diff 0.00%
PS 32 DIV 0x0001 Real 2062500 Diff -37.50%
2000000 Baud PS 4 DIV 0x0008 Real 2062500 Diff - 3.13%
PS 32 DIV 0x0001 Real 2062500 Diff - 3.13%
2500000 Baud PS 4 DIV 0x0007 Real 2357142 Diff 5.71%
PS 32 DIV 0x0001 Real 2062500 Diff 17.50%
3000000 Baud PS 4 DIV 0x0006 Real 2750000 Diff 8.33%
PS 32 DIV 0x0001 Real 2062500 Diff 31.25%
3500000 Baud PS 4 DIV 0x0005 Real 3300000 Diff 5.71%
PS 32 DIV 0x0001 Real 2062500 Diff 41.07%
4000000 Baud PS 4 DIV 0x0004 Real 4125000 Diff - 3.13%
PS 32 DIV 0x0001 Real 2062500 Diff 48.44%
Signed-off-by: Frank Benkert <frank.benkert@avat.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
All of them do not use the ugly interface defined in that header.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It uses pointers to pci_dev, but compiler complains it doesn't know
it:
In file included from .../m32r_sio.c:53:
.../m32r_sio.h:21: warning: "struct pci_dev" declared inside parameter list
.../m32r_sio.h:21: warning: its scope is only this definition or declaration, which is probably not what you want
.../m32r_sio.h:22: warning: "struct pci_dev" declared inside parameter list
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We want to know the value of the atomic variable in intr_connect after
the increment. But atomic_inc doesn't, per definition, return the
value. It is just a pure coincidence that ia64 defines atomic_inc as
atomic_inc_return.
So fix this mistake by using atomic_inc_return properly.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Checking if tty->index is in bounds is not needed. The tty has the
index set in the initial open. This is done in get_tty_driver. And it
can be only in interval <0,driver->num).
So remove the tests which check exactly this interval. Some are
left untouched as they check against the current backing device count.
(Leaving apart that the check is racy in most of the cases.)
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
All num, magic and owner are set by alloc_tty_driver. No need to
re-set them on each allocation site.
pti driver sets something different to what it passes to
alloc_tty_driver. It is not a bug, since we don't use the lines
parameter in any way. Anyway this is fixed, and now we do the right
thing.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The following commit: be4b028195
(tty: serial: OMAP: block idle while the UART is transferring data in PIO mode),
is introducing an oops if OMAP is booted using device tree blob because
the pdata will not be initialized.
Check if pdata is set before de-referencing it.
Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Reviewed-by: Paul Walmsley <paul@pwsan.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In DMA-operated uart, I found that rx data can be taken by the UART
interrupts during the DMA irq handler. pl011_int is occurred just
before it goes inside spin_lock_irq. When it returns to the callback,
DMA buffer already has been flushed. Then, pl011_dma_rx_chars gets
invalid data. So I add check for the residue as the patch bellow.
Signed-off-by: Chanho Min <chanho.min@lge.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Without that fix machines having a s3c2442 CPU have something
like that in dmesg:
samsung-uart s3c2440-uart.0: could not find driver data
samsung-uart s3c2440-uart.1: could not find driver data
samsung-uart s3c2440-uart.2: could not find driver data
And serial is never initialized.
The previous log was obtained trough early printk on the gta02
machine.
Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@no-log.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/tty/serial/mux.c included 'linux/tty.h' twice, remove
the duplicate.
Signed-off-by: Danny Kukawka <danny.kukawka@bisect.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There are multiple users of this file from different source
paths now, and rather than have ../ paths in include statements,
just move the file to the linux header dir.
Suggested-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The receive FIFO wakeup latency estimate in the omap-serial driver is
three orders of magnitude too small. This effectively prevents the
MPU from going to a low-power state when CONFIG_CPU_IDLE=y. This is a
major power management regression and masks some other FIFO-related
bugs in the driver.
Fix by correcting the most egregious problem in the RX wakeup latency
estimate. There are several other flaws in the estimator; these will
be fixed by a separate patch series intended for 3.4.
The difference in low-power states with this patch can be observed via
debugfs in pm_debug/count.
This estimate does not have any effect when CONFIG_CPU_IDLE=n.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Alan Cox <alan@linux.intel.com>
Acked-by: Govindraj.R <govindraj.raja@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Prevent OMAP UARTs from going idle while they are still transferring
data in PIO mode. This works around an oversight in the OMAP UART
hardware present in OMAP34xx and earlier: an idle UART won't send a
wakeup when the TX FIFO threshold is reached. This causes long delays
during data transmission when the MPU powerdomain enters a low-power
mode. The MPU interrupt controller is not able to respond to
interrupts when it's in a low-power state, so the TX buffer is not
refilled until another wakeup event occurs.
This fix changes the erratum i291 DMA idle workaround. Rather than
toggling between force-idle and no-idle, it will toggle between
smart-idle and no-idle. The important part of the workaround is the
no-idle part, so this shouldn't result in any change in behavior.
This fix should work on all OMAP UARTs. Future patches intended for
the 3.4 merge window will make this workaround conditional on a
"feature" flag, and will use the OMAP36xx+ TX event wakeup support.
Thanks to Kevin Hilman <khilman@ti.com> for mentioning the erratum i291
workaround, which led to the development of this approach.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: Govindraj.R <govindraj.raja@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In the (default) PIO mode, use a one-byte RX FIFO threshold. The OMAP
UART IP blocks do not appear to be capable of waking the system under
an RX timeout condition. Since the previous RX FIFO threshold was 16
bytes, this meant that omap-serial.c did not become aware of any
received data until all those bytes arrived or until another UART
interrupt occurred. This made the serial console and presumably other
serial applications (GPS, serial Bluetooth) unusable or extremely
slow. A 1-byte RX FIFO threshold also allows the MPU to enter a
low-power consumption state while waiting for the FIFO to fill.
This can be verified using the serial console by comparing the
behavior when "0123456789abcde" is pasted in from another window, with
the behavior when "0123456789abcdef" is pasted in. Since the former
string is less than sixteen bytes long, the string is not echoed for
some time, while the latter string is echoed immediately.
DMA operation is unaffected by this patch.
Thanks to Russell King - ARM Linux <linux@arm.linux.org.uk> for some
additional information on the standard behavior of the RX timeout
event, which was used to improve this commit description.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Govindraj Raja <govindraj.r@ti.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Russell King <linux@arm.linux.org.uk>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This allows altera_uart to be used for KGDB debugging over serial line.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The function has no users inside the tree and the nios2
(out-of-mainline) port doesn't use it either (anymore).
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pch_uart_hal_request() has parameters which it never uses, also
it is very short, so merge it with its caller to make code cleaner.
No functional changes at all.
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The short get_msr() has some unnecessary code and only used once,
so merge it with its caller to make code cleaner. No functional
change at all.
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This driver will be use as interfaces for multiple kinds of
devices like Bluetooth/GPS etc, this debug hook will make driver
debugging much easier.
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 9bef3d4197
"serial: group all the 8250 related code together"
inadvertently swept up the m32r driver in the move, because
it had comments mentioning 8250 registers within it. However
these are only there by nature of the driver being based off
the 8250 source code -- the hardware itself does not actually
have any relation to the original 8250 style UARTs.
Reported-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
On sparc, there is a build failure:
drivers/tty/serial/8250/8250.c:48:21: error: suncore.h: No such file or directory
drivers/tty/serial/8250/8250.c:3275: error: implicit declaration of function 'sunserial_register_minors'
drivers/tty/serial/8250/8250.c:3305: error: implicit declaration of function 'sunserial_unregister_minors'
this is due to commit 9bef3d4197
(serial: group all the 8250 related code together) moved these files
into 8250/ subdirectory, but forgot to change the reference
to drivers/tty/serial/suncore.h.
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This should be added for EXYNOS4212 and EXYNOS4412 SoCs.
Cc: Thomas Abraham <thomas.abraham@linaro.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The receive FIFO wakeup latency estimate in the omap-serial driver is
three orders of magnitude too small. This effectively prevents the
MPU from going to a low-power state when CONFIG_CPU_IDLE=y. This is a
major power management regression and masks some other FIFO-related
bugs in the driver.
Fix by correcting the most egregious problem in the RX wakeup latency
estimate. There are several other flaws in the estimator; these will
be fixed by a separate patch series intended for 3.4.
The difference in low-power states with this patch can be observed via
debugfs in pm_debug/count.
This estimate does not have any effect when CONFIG_CPU_IDLE=n.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Alan Cox <alan@linux.intel.com>
Acked-by: Govindraj.R <govindraj.raja@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Prevent OMAP UARTs from going idle while they are still transferring
data in PIO mode. This works around an oversight in the OMAP UART
hardware present in OMAP34xx and earlier: an idle UART won't send a
wakeup when the TX FIFO threshold is reached. This causes long delays
during data transmission when the MPU powerdomain enters a low-power
mode. The MPU interrupt controller is not able to respond to
interrupts when it's in a low-power state, so the TX buffer is not
refilled until another wakeup event occurs.
This fix changes the erratum i291 DMA idle workaround. Rather than
toggling between force-idle and no-idle, it will toggle between
smart-idle and no-idle. The important part of the workaround is the
no-idle part, so this shouldn't result in any change in behavior.
This fix should work on all OMAP UARTs. Future patches intended for
the 3.4 merge window will make this workaround conditional on a
"feature" flag, and will use the OMAP36xx+ TX event wakeup support.
Thanks to Kevin Hilman <khilman@ti.com> for mentioning the erratum i291
workaround, which led to the development of this approach.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: Govindraj.R <govindraj.raja@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In the (default) PIO mode, use a one-byte RX FIFO threshold. The OMAP
UART IP blocks do not appear to be capable of waking the system under
an RX timeout condition. Since the previous RX FIFO threshold was 16
bytes, this meant that omap-serial.c did not become aware of any
received data until all those bytes arrived or until another UART
interrupt occurred. This made the serial console and presumably other
serial applications (GPS, serial Bluetooth) unusable or extremely
slow. A 1-byte RX FIFO threshold also allows the MPU to enter a
low-power consumption state while waiting for the FIFO to fill.
This can be verified using the serial console by comparing the
behavior when "0123456789abcde" is pasted in from another window, with
the behavior when "0123456789abcdef" is pasted in. Since the former
string is less than sixteen bytes long, the string is not echoed for
some time, while the latter string is echoed immediately.
DMA operation is unaffected by this patch.
Thanks to Russell King - ARM Linux <linux@arm.linux.org.uk> for some
additional information on the standard behavior of the RX timeout
event, which was used to improve this commit description.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Govindraj Raja <govindraj.r@ti.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Russell King <linux@arm.linux.org.uk>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We transform the offenders into a test of irq <= 0 which will be ok while
the ARM people get their platform sorted. Once that is done (or in a while
if they don't do it anyway) then we will change them all to !irq checks.
For arch specific drivers that are already using NO_IRQ = 0 we just test
against zero so we don't need to re-review them later.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
All production devices operate in the Oaktrail configuration with legacy PC
elements present and an ACPI BIOS. Continue stripping out the Moorestown
elements from the tree leaving Medfield.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This reverts commit 0a697b2225 as Paul
wants to rework it.
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Govindraj Raja <govindraj.r@ti.com>
Cc: Kevin Hilman <khilman@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This reverts commit 43cf7c0beb as Paul
wants to redo it.
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Govindraj Raja <govindraj.r@ti.com>
Cc: Kevin Hilman <khilman@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The synchronize_rcu() call resulting from making every serial driver
wake-up capable (commit b3b708fa) slows boot down on my Tegra2x system
(with CONFIG_PREEMPT disabled).
But this is avoidable since it is the device_set_wakeup_enable() and then
subsequence disable which causes the delay. We might as well just make
the device wakeup capable but not actually enable it for wakeup until
needed.
Effectively the current code does this:
device_set_wakeup_capable(dev, 1);
device_set_wakeup_enable(dev, 1);
device_set_wakeup_enable(dev, 0);
We can just drop the last two lines.
Before this change my boot log says:
[ 0.227062] Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
[ 0.702928] serial8250.0: ttyS0 at MMIO 0x70006040 (irq = 69) is a Tegra
after:
[ 0.227264] Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
[ 0.227983] serial8250.0: ttyS0 at MMIO 0x70006040 (irq = 69) is a Tegra
for saving of 450ms.
Suggested-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Protect against pl011_console_write() and the interrupt for
the console UART running concurrently on different CPUs.
Otherwise the console_write could spin for a long time
waiting for the UART to become not busy, while the other
CPU continuously services UART interrupts and keeps the
UART busy.
The checks for sysrq and oops_in_progress are taken
from 8250.c.
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Reviewed-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Reviewed-by: Bibek Basu <bibek.basu@stericsson.com>
Reviewed-by: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
In present driver, shutdown clears RTS and DTR in CR register. But the
documentation "Documentation/serial/driver" suggests not to disable
RTS and DTR in shutdown(). Also RTS and DTR is preserved between shutdown
and startup calls, i.e. these are restored in startup if they were enabled
while doing shutdown. So that if RTS and DTR are set using pl011_set_mctrl
then it should continue even after shutdown->startup sequence.
For throttling/unthrottling user should call pl011_set_mctrl.
Signed-off-by: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
It seems that when the transmit FIFO threshold is reached on OMAP
UARTs, it does not result in a PRCM wakeup. This appears to be a
silicon bug. This means that if the MPU powerdomain is in a low-power
state, the MPU will not be awakened to refill the FIFO until the next
interrupt from another device.
The best solution, at least for the short term, would be for the OMAP
serial driver to call a OMAP subarchitecture function to prevent the
MPU powerdomain from entering a low power state while the FIFO has
data to transmit. However, we no longer have a clean way to do this,
since patches that add platform_data function pointers have been
deprecated by the OMAP maintainer. So we attempt to work around this
as well. The workarounds depend on the setting of CONFIG_CPU_IDLE.
When CONFIG_CPU_IDLE=n, the driver will now only transmit one byte at
a time. This causes the transmit FIFO threshold interrupt to stay
active until there is no more data to be sent. Thus, the MPU
powerdomain stays on during transmits. Aside from that energy
consumption penalty, each transmitted byte results in a huge number of
UART interrupts -- about five per byte. This wastes CPU time and is
quite inefficient, but is probably the most expedient workaround in
this case.
When CONFIG_CPU_IDLE=y, there is a slightly more direct workaround:
the PM QoS constraint can be abused to keep the MPU powerdomain on.
This results in a normal number of interrupts, but, similar to the
above workaround, wastes power by preventing the MPU from entering
WFI.
Future patches are planned for the 3.4 merge window to implement more
efficient, but also more disruptive, workarounds to these problems.
DMA operation is unaffected by this patch.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Govindraj Raja <govindraj.r@ti.com>
Cc: Kevin Hilman <khilman@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Ensure FIFO levels are set correctly in non-DMA mode (the default).
This patch will cause a receive FIFO threshold interrupt to be raised when
there is at least one byte in the RX FIFO. It will also cause a transmit
FIFO threshold interrupt when there is only one byte remaining in the TX
FIFO.
These changes fix the receive interrupt problem and part of the
transmit interrupt problem. A separate set of issues must be worked
around for the transmit path to have a basic level of functionality; a
subsequent patch will address these.
DMA operation is unaffected by this patch.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Govindraj Raja <govindraj.r@ti.com>
Cc: Kevin Hilman <khilman@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The function serial_omap_restore_context is called only from
serial_omap_runtime_resume which depends on CONFIG_PM_RUNTIME. Make
serial_omap_restore_context also compile conditionally.
if CONFIG_PM_RUNTIME is not defined below warn may be seen.
LD net/xfrm/built-in.o
drivers/tty/serial/omap-serial.c:1524: warning: 'serial_omap_restore_context' defined but not used
CC drivers/tty/vt/selection.o
Acked-by: Govindraj.R <govindraj.raja@ti.com>
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
