Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.
The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around. On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).
Where appropriate, an arch may override the generic storage facility and do
something different with the variable. On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.
Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions. Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller. A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.
I've build this code with allyesconfig for x86_64 and i386. I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.
This will affect all archs. Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:
struct pt_regs *old_regs = set_irq_regs(regs);
And put the old one back at the end:
set_irq_regs(old_regs);
Don't pass regs through to generic_handle_irq() or __do_IRQ().
In timer_interrupt(), this sort of change will be necessary:
- update_process_times(user_mode(regs));
- profile_tick(CPU_PROFILING, regs);
+ update_process_times(user_mode(get_irq_regs()));
+ profile_tick(CPU_PROFILING);
I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().
Some notes on the interrupt handling in the drivers:
(*) input_dev() is now gone entirely. The regs pointer is no longer stored in
the input_dev struct.
(*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does
something different depending on whether it's been supplied with a regs
pointer or not.
(*) Various IRQ handler function pointers have been moved to type
irq_handler_t.
Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
The at91_serial driver can be used with both AT32 and AT91 devices
from Atmel and has therefore been renamed atmel_serial. The only
thing left is to rename PORT_AT91 PORT_ATMEL.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make sysrq-K work on serial console by passing in the tty.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
A serial card might have been removed when the system is resumed.
This results in a suspended port being shut down, which results in
the ports shutdown method being called twice in a row. This causes
BUGs. Avoid this by tracking the suspended state separately from
the initialised state.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The following patch gets rid of CONFIG_TSI108_BRIDGE. I add UPIO_TSI to
handle IIR and IER register in serial_in and serial_out.
(1) the reason to rewrite serial_in:
TSI108 rev Z1 version ERRATA. Reading the UART's Interrupt
Identification Register (IIR) clears the Transmit Holding Register
Empty (THRE) and Transmit buffer Empty (TEMP) interrupts even if they
are not enabled in the Interrupt Enable Register (IER). This leads to
loss of the interrupts. Interrupts are not cleared when reading UART
registers as 32-bit word.
(2) the reason to rewrite serial_out:
Check for UART_IER_UUE bit in the autoconfig routine. This section
of autoconfig is excluded for Tsi108/109 because bits 7 and 6 are
reserved for internal use. They are R/W bits. In addition to
incorrect identification, changing these bits (from 00) will make
Tsi108/109 UART non-functional.
Signed-off-by: Roy Zang <tie-fei.zang@freescale.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* 'devel' of master.kernel.org:/home/rmk/linux-2.6-serial:
[SERIAL] Ensure 8250_pci quirks are not marked __devinit
[SERIAL] Convert fifosize to an unsigned int
Some UARTs have more than 255 bytes of FIFO, which can't be
represented by an unsigned char. Change the kernel's internal
structure to be an unsigned int, but still export an unsigned char
via the TIOCGSERIAL ioctl. If the TIOCSSERIAL ioctl provides a
fifo size of 0, assume this means "don't change" otherwise we'll
corrupt the larger fifo sizes.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Ben Dooks
Serial port support for the on-board UART blocks
on the Samsung S3C2412 and S3C2413 UARTs.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Andrew Victor
This patch includes a number of updates to the AT91RM9200 serial driver.
Changes include:
1. Conversion to a platform_driver. [Ivan Kokshaysky]
2. Replaced all references to AT91RM9200 with AT91. This driver can now
also be used for the AT91SAM9216.
3. Allow TIOCM_LOOP to configure local loopback mode.
4. Cleaned up the 'read_status_mask' usage and interrupt handler code.
[Chip Coldwell]
5. Suspend/resume support. [David Brownell]
There are a few 'unused variable' warning when compiling this - I
removed the new DMA support to keep this first patch simpler.
Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The locking for the uart_port is over complicated, and can be
simplified if we introduce a flag to indicate that a port is "dead"
and will be removed.
This also helps the validator because it removes a case of non-nested
unlock ordering.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
* master.kernel.org:/home/rmk/linux-2.6-serial:
[SERIAL] Merge avlab serial board entries in parport_serial
[SERIAL] kernel console should send CRLF not LFCR
Glen Turner reported that writing LFCR rather than the more
traditional CRLF causes issues with some terminals.
Since this aflicts many serial drivers, extract the common code
to a library function (uart_console_write) and arrange for each
driver to supply a "putchar" function.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Since it can do things like BREAK and HUP, we implement
this as a serial uart driver.
This still needs interrupt probing code, as I haven't figured
out how interrupts will work or be probed for on SUN4V yet.
Signed-off-by: David S. Miller <davem@davemloft.net>
Same reasoning as commit 747c8a5594
but this time we're making uart_port flags a bitwise type - not
all of these flags correspond with the old ASYNC_ flags, so there
is the possibility for bugs if the wrong ASYNC_* constants are
used. Always use UPF_* constants for uart_port->flags.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The previous change found a bug in the serial SAK handling - because
we were looking for UPF_SAK set in uart_info->flags, we would never
raise a SAK condition. UPF_SAK is in uart_port->flags.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The potential for confusing the flags is fairly high. Make
uart_info's flags a bitwise type so sparse can check that the
right flag definitions are used with the right structure.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The functionality UPF_BOOT_ONLYMCA provided has been replaced by
the 8250_mca module, which only registers MCA ports if MCA is
present.
UPF_AUTOPROBE has no functional effect - in fact, it's never
tested. Only ibmasm set the flag.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
semaphore to mutex conversion.
the conversion was generated via scripts, and the result was validated
automatically via a script as well.
build and boot tested.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Andrew Victor
This patch adds support to the 2.6 kernel series for the Atmel
AT91RM9200 processor.
This patch is the Serial driver.
This version uses the newly re-written GPL'ed hardware headers.
Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Sascha Hauer
This patch adds PORT_NETX for supporting the Hilscher netx embedded
UARTs.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The offsets of the registers are in a different place, and
some parts cannot handle a full set of modem control signals.
Signed-off-by: Pantelis Antoniou <pantelis@embeddedalley.ocm>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Proud member of Uglyhacks'R'US.
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Russell King <rmk+lkml@arm.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When SUPPORT_SYSRQ is false, gcc can emit warnings for
the uart_handle_sysrq_char() that results. Using an
empty inline returning zero kills the warning.
Signed-off-by: David S. Miller <davem@davemloft.net>
Patch from Sascha Hauer
This patch adds support for setting and getting RTS / CTS via
set_mtctrl / get_mctrl functions.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The start_tx and stop_tx methods were passed a flag to indicate
whether the start/stop was from the tty start/stop callbacks, and
some drivers used this flag to decide whether to ask the UART to
immediately stop transmission (where the UART supports such a
feature.)
There are other cases when we wish this to occur - when CTS is
lowered, or if we change from soft to hard flow control and CTS
is inactive. In these cases, this flag was false, and we would
allow the transmitter to drain before stopping.
There is really only one case where we want to let the transmitter
drain before disabling, and that's when we run out of characters
to send.
Hence, re-jig the start_tx and stop_tx methods to eliminate this
flag, and introduce new functions for the special "disable and
allow transmitter to drain" case.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Use tabs for formatting like anywhere else in this file.
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I think it's about time to make the build a little more vocal about the
expiry of these functions. Due to recent discussions with problems in
the console initialisation vs power manglement, I'd like to move the
date forward to September.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Add uart_insert_char(), which handles inserting characters into the
flip buffer. This helper function handles the correct semantics
for handling overrun in addition to inserting normal characters.
Signed-off-by: Russell King <rmk@arm.linux.org.uk>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
David Howells