The driver handles MPC83xx, MPC85xx and MPC86xx SPI controllers, so rename
the file for clarity.
Suggested-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch removes #if 0'ed code, and spi_mpc83xx->busy variable that is
used by that dead snippet only.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mpc83xx_spi_work() is quite large, with up to five indentation levels and
is quite difficult to read.
So, split the function in two parts:
1. mpc83xx_spi_work() now only traverse queued spi messages;
2. mpc83xx_spi_do_one_msg() only manages single messages.
There should be no functional changes.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Checkpatch is spitting errors when seeing the rename patch, so fix the
errors prior to moving.
Following errors and warnings were fixed:
WARNING: Use #include <linux/io.h> instead of <asm/io.h>
#1027: FILE: drivers/spi/spi_mpc8xxx.c:37:
+#include <asm/io.h>
ERROR: "foo * bar" should be "foo *bar"
#1111: FILE: drivers/spi/spi_mpc8xxx.c:121:
+static inline void mpc83xx_spi_write_reg(__be32 __iomem * reg, u32 val)
ERROR: "foo * bar" should be "foo *bar"
#1116: FILE: drivers/spi/spi_mpc8xxx.c:126:
+static inline u32 mpc83xx_spi_read_reg(__be32 __iomem * reg)
ERROR: "foo * bar" should be "foo *bar"
#1125: FILE: drivers/spi/spi_mpc8xxx.c:135:
+ type * rx = mpc83xx_spi->rx; \
ERROR: "foo * bar" should be "foo *bar"
#1135: FILE: drivers/spi/spi_mpc8xxx.c:145:
+ const type * tx = mpc83xx_spi->tx; \
WARNING: suspect code indent for conditional statements (16, 25)
#1504: FILE: drivers/spi/spi_mpc8xxx.c:514:
+ while (((event =
[...]
+ cpu_relax();
Following warnings were left over, since fixing them will hurt the
readability. We'd better fix them by lowering the indentation level by
splitting mpc83xx_spi_work function into two parts.
WARNING: line over 80 characters
#1371: FILE: drivers/spi/spi_mpc8xxx.c:381:
+ status = mpc83xx_spi_setup_transfer(spi, t);
WARNING: line over 80 characters
#1392: FILE: drivers/spi/spi_mpc8xxx.c:402:
+ mpc83xx_spi_chipselect(spi, BITBANG_CS_INACTIVE);
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is needed for some underlaying GPIO controllers that may be a bit
slow, or if chip-select signal need some time to stabilize.
For what it's worth, we already have the similar delay for chip-select
de-assertion case.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When a platform is running at high frequencies it's not always possible to
scale-down a frequency to a requested value, and using mmc_spi driver this
leads to the following printk flood during card polling:
...
mmc_spi spi32766.0: Requested speed is too low: 400000 Hz. Will use
520828 Hz instead.
mmc_spi spi32766.0: Requested speed is too low: 400000 Hz. Will use
520828 Hz instead.
...
Fix this by using WARN_ONCE(), it's better than the flood, and also better
than turning dev_err() into dev_dbg(), since we actually want to warn that
some things may not work correctly.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move some common spi_setup() error checks into the SPI framework from the
spi_master controller drivers:
- Add a new "mode_bits" field to spi_master
- Use that in spi_setup to validate the spi->mode value being
requested. Setting this new field is now mandatory for any
controller supporting more than vanilla SPI_MODE_0.
- Update all spi_master drivers to:
* Initialize that field
* Remove current spi_setup() checks using that value.
This is a net minor code shrink.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Start moving some spi_setup() functionality into the SPI core from the
various spi_master controller drivers:
- Make that function stop being an inline;
- Move two common idioms from drivers into that new function:
* Default bits_per_word to 8 if that field isn't set
* Issue a standardized dev_dbg() message
This is a net minor source code shrink, and supports enhancments found in
some follow-up patches.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Do not take the size of a pointer to determine the size of the pointed-to
type.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Acked-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@gate.crashing.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Implement full support for OF SPI bindings. Now the driver can manage its
own chip selects without any help from the board files and/or fsl_soc
constructors.
The "legacy" code is well isolated and could be removed as time goes by.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The main purpose of this patch is to pass 'struct spi_device' to the chip
select handling routines. This is needed so that we could implement
full-fledged OpenFirmware support for this driver.
While at it, also:
- Replace two {de,activate}_cs routines by single cs_contol().
- Don't duplicate platform data callbacks in mpc83xx_spi struct.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The patch fixes following sparse warnings:
CHECK spi_mpc83xx.c
spi_mpc83xx.c:145:1: warning: symbol 'mpc83xx_spi_rx_buf_u8' was not declared. Should it be static?
spi_mpc83xx.c:146:1: warning: symbol 'mpc83xx_spi_rx_buf_u16' was not declared. Should it be static?
spi_mpc83xx.c:147:1: warning: symbol 'mpc83xx_spi_rx_buf_u32' was not declared. Should it be static?
spi_mpc83xx.c:148:1: warning: symbol 'mpc83xx_spi_tx_buf_u8' was not declared. Should it be static?
spi_mpc83xx.c:149:1: warning: symbol 'mpc83xx_spi_tx_buf_u16' was not declared. Should it be static?
spi_mpc83xx.c:150:1: warning: symbol 'mpc83xx_spi_tx_buf_u32' was not declared. Should it be static?
spi_mpc83xx.c:175:32: warning: incorrect type in initializer (different address spaces)
spi_mpc83xx.c:175:32: expected void *tmp_ptr
spi_mpc83xx.c:175:32: got unsigned int [noderef] <asn:2>*<noident>
spi_mpc83xx.c:183:26: warning: incorrect type in argument 1 (different address spaces)
spi_mpc83xx.c:183:26: expected unsigned int [noderef] [usertype] <asn:2>*reg
spi_mpc83xx.c:183:26: got void *tmp_ptr
spi_mpc83xx.c:184:26: warning: incorrect type in argument 1 (different address spaces)
spi_mpc83xx.c:184:26: expected unsigned int [noderef] [usertype] <asn:2>*reg
spi_mpc83xx.c:184:26: got void *tmp_ptr
spi_mpc83xx.c:287:31: warning: incorrect type in initializer (different address spaces)
spi_mpc83xx.c:287:31: expected void *tmp_ptr
spi_mpc83xx.c:287:31: got unsigned int [noderef] <asn:2>*<noident>
spi_mpc83xx.c:295:25: warning: incorrect type in argument 1 (different address spaces)
spi_mpc83xx.c:295:25: expected unsigned int [noderef] [usertype] <asn:2>*reg
spi_mpc83xx.c:295:25: got void *tmp_ptr
spi_mpc83xx.c:296:25: warning: incorrect type in argument 1 (different address spaces)
spi_mpc83xx.c:296:25: expected unsigned int [noderef] [usertype] <asn:2>*reg
spi_mpc83xx.c:296:25: got void *tmp_ptr
spi_mpc83xx.c:486:13: warning: symbol 'mpc83xx_spi_irq' was not declared. Should it be static?
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Error out on transfer length != multiple of bytes per word with -EINVAL.
Fixes a buffer overrun crash if length < bytes per word.
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Acked-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit a61f5345 (spi_mpc83xx clockrate fixes) broke clockrate calculation
for low speeds. SPMODE_DIV16 should be set if the divider is higher than
64, not only if the divider gets clipped to 1024.
Furthermore, the clipping check was off by a factor 16 as well.
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This updates the SPI clock rate calculations for the spi_mpc83xx driver.
Some boundary conditions were wrong, and in several cases divide-by-16
wasn't always needed
Signed-off-by: Chen Gong <g.chen@freescale.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The current driver may cause glitches on SPI CLK line since one must disable
the SPI controller before changing any HW settings. Fix this by implementing
a local spi_transfer function that won't change speed and/or word size while
CS is active.
While doing that heavy lifting a few other issues were addressed too:
- Make word size 16 and 32 work too.
- Honor bits_per_word and speed_hz in spi transaction.
- Optimize the common path.
This also stops using the "bitbang" framework (except for a few constants).
[Roel Kluin <12o3l@tiscali.nl>: "irq" needs to be signed]
Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__FUNCTION__ is gcc-specific, use __func__
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since 43cc71eed1, the platform modalias is
prefixed with "platform:". Add MODULE_ALIAS() to the hotpluggable SPI
platform drivers, to allow module auto loading.
[dbrownell@users.sourceforge.net: more drivers: registration fixes]
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In case of QE we can use brg-frequency (which is qeclk/2).
Thus no need to divide sysclk in the spi_mpc83xx.
This patch also adds code to use get_brgfreq() on QE chips.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Shrink the runtime footprint of various SPI drivers:
- Move the probe() routine into the init section where practical,
using platform_driver_probe() to make that safe. This often saves
around 1KB. Using platform_driver_probe() can also be a correctness
fix, if the probe routine is already marked __init but the driver
struct keeps a dangling pointer to it after init section removal.
- Likewise move remove() routines into the exit sections.
These changes would be inappropriate iff the platform devices were
actually hotpluggable (e.g. they're found on optional addon cards,
or in an FPGA that's dynamically reprogrammed). In these cases,
that's not the situation; it's an SOC controller and the only device
is initialized before these drivers.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the spi_mpc83xx driver receives a tx_buf pointer which is NULL, it
only writes one zero filled word to the transmit register. If the driver
expects to receive more than one word it will wait forever for a second
receive interrupt. With this patch the controller will shift out zeroes
until all words have been received.
Signed-off-by: Jan Andersson <jan@gaisler.com>
Tested-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Update various SPI drivers so they properly support
- coldplug through "modprobe $(cat /sys/devices/.../modalias)"
- hotplug through "modprobe $(MODALIAS)"
The basic rule for platform, SPI, and (new style) I2C drivers is just
to make sure that modprobing the driver name works. In this case, all
the relevant drivers are platform drivers, and this patch either
(a) Changes the driver name, if no in-tree code would break;
this is simpler and thus preferable in the long term.
(b) Adds MODULE_ALIAS directives, when in-tree platforms declare
devices using the current driver name; less desirable.
Most systems will link SPI controller drivers statically, but
there's no point in being needlessly broken.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Jean Delvare <khali@linux-fr.org>
Acked-by: Andrei Konovalov <akonovalov@ru.mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Long ago I've noticed (but didn't pay much attention) that
spi_mpc83xx using PM calculations that differs from what
specs describe. I.e.
u8 pm = mpc83xx_spi->spibrg / (spi->max_speed_hz * 4);
While specs says: "The SPI baud rate generator clock source (either
system clock or system clock divided by 16, depending on DIV16 bit) is
divided by 4 * ([PM] + 1), a range from 4 to 64.".
Thus " - 1" is missing in the spi_mpc83xx's formula.
Why nobody noticed that bug? Probably because sysclk usually less then
user expects, e.g. you expect 200 MHz, but real clock is 198 MHz,
and integer rounding helps when this formula is used.
Suppose it's SPI in QE, SYSCLK at 198 MHz, thus SPIBRG at 99MHz, 25 MHz
requested.
PM = (99MHz / ( 25 MHz * 4 )), PM == 0, output SPICLK will be 24.75 MHz
At lower frequencies this bug is more noticeable, though.
And this bug shows itself in all its beauty if SYSCLK is equal or a bit
more than you expect (200 MHz SYSCLK, 100 MHz SPIBRG):
PM = (100MHz / ( 25 MHz * 4 )), PM == 1, output SPICLK will be 12.625 MHz!
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For MPC8349E input to the SPI Baud Rate Generator is SYSCLK, but it's
SYSCLK/2 for MPC8323E (SPI in QE). Fix this, and remove confusion by
renaming the mpc83xx_spi->sysclk member as mpc83xx_spi->spibrg.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This exposes the hardware loopback mode to drivers, primarily for testing.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
spi_mpc83xx should use other shifts when running in QE+LSB mode.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This controller supports LSB-first transfers; let drivers use them.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Documentation clearly states, that mode should not be changed till
SPMODE_ENABLE bit set. I've seen hangs w/o this patch.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Quicc Engine enabled mpc83xx CPU's has a somewhat different HW interface to
the SPI controller. This patch adds a qe_mode knob that sees to that
needed adaptions are performed.
Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The MPC83xx SPI controller clock divider can divide the system clock by not
more then 1024. The spi_mpc83xx driver does not check this and silently
writes garbage to the SPI controller registers when asked to run at lower
frequencies. I've tried to run the SPI on a 266MHz MPC8349E with 100kHz
for debugging a bus problem and suddenly was confronted with a 2nd problem
to debug.. ;-)
The patch adds an additional check which avoids writing garbage to the SPI
controller registers and warn the user about it. This might help others to
avoid simmilar problems.
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Minor SPI controller driver updates: make the setup() methods reject
spi->mode bits they don't support, by masking aginst the inverse of bits
they *do* support. This insures against misbehavior later when new mode
bits get added.
Most controllers can't support SPI_LSB_FIRST; more handle SPI_CS_HIGH.
Support for all four SPI clock/transfer modes is routine.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some issues were recently turned up with the current specification of what
it means for spi_transfer.tx_buf to be null, as part of transfers which are
(from the SPI protocol driver perspective) pure reads.
Specifically, that it seems better to change the TX behaviour there from
"undefined" to "will shift zeroes". This lets protocol drivers (like the
ads7846 driver) depend on that behavior. It's what most controller drivers
in the tree are already doing (with one exception and one case of driver
wanting-to-oops), it's what Microwire hardware will necessarily be doing,
and it removes an issue whereby certain security audits would need to
define such a value anyway as part of removing covert channels.
This patch changes the specification to require shifting zeroes, and
updates all currently merged SPI controller drivers to do so.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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)
This driver supports the SPI controller on the MPC83xx SoC devices from
Freescale. Note, this driver supports only the simple shift register SPI
controller and not the descriptor based CPM or QUICCEngine SPI controller.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
