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)
Some Ricoh controllers only respect a full reset when there is no card in the
slot. As we wait for the reset to complete, we must avoid even requesting
those resets on the buggy controllers.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Sprinkle some mmiowb() where needed (writeX() before unlock()).
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Clarify my (Pierre's) position on which GPL versions apply. The patch only
touches the source files where I am the only major author. The people who
have made the minor commits to the files have been contacted and have no
issues with this change.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Some MMC hosts can only handle log2 block sizes. Unfortunately,
the MMC password support needs to be able to send non-log2 block
sizes. Provide a capability so that the MMC password support can
decide whether it should use this support or not.
The unfortunate side effect of this host limitation is that any
MMC card protected by a password which is not a log2 block size
can not be accessed on a host which only allows a log2 block size.
This change just adds the flag. The MMC password support code
needs updating to use it (if and when it is finally submitted.)
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Add a capability flag for drivers to set when they can perform multi-
block transfers to cards _and_ correctly report the number of bytes
transferred should an error occur.
The last point is very important - if a driver reports more bytes than
were actually accepted by the card and an error occurs, there is the
possibility for data loss.
Pierre Ossman provided the patch for wbsd and sdhci.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
O2 Micro's controllers have a larger specification version value and are
therefore denied by the driver. When bypassing this check they seem to work
fine. This patch makes the code a bit more forgiving by changing the error
to a warning.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
There was a writel() being used on a 16-bit register.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
When there is remaining blocks untransferred, we get two error messages saying
almost the same thing. Make sure at most one is shown.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Some controllers incorrectly report that the cannot do DMA. Forcefully enable
it for those that we know it works fine on.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Some controllers fail to complete a reset unless you touch the clock register
first.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
New version number for sdhci driver.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
As some specific controllers will have bugs, we need a way to map special
behaviour to certain hardware.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Properly test for controller interface to see if it's DMA capable. As many
controllers are misconfigured in this regard, also add debug parameters to
force DMA support either way.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The specification states that the capabilities register might need a reset to
get correct values after boot up.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Check the interface version of the controller and bail out if it's an unknown
version.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Conform to the sdhci specification as to which inhibit bits should be checked
at different times.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The controller has an upper limit on the block size. Make sure we do not
cross it.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The sdhci controllers will issue an interrupt when a configurable number of
bytes have been transfered using DMA. The purpose is to handle multiple,
scattered memory pages.
Unfortunately, it requires that all transfers are completely aligned to
memory pages, which we cannot guarantee. So we just disable the function.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The sdhci controllers operate with blocks, not bytes. The PIO routines must
therefore make sure that the minimum unit transfered is a complete block.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The specification says that interrupts should be cleared before the source is
removed. We should also not set unknown bits.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The sdhci specification states that some registers must be written to in a
specific order.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Use the give timeout clock and calculate a proper timeout instead of using the
maximum at all times.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The reset register is automatically cleared when the reset has completed.
Hence, we should busy wait and not have a fixed delay.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The current timeout loop assume that jiffies are updated. This might not be
the case depending on locks and if the kernel is compiled without preemption.
Change the system to use a counter and fixed delays.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The sdhci controllers can support up to three voltage levels. Detect which
and report back to the MMC layer.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
As sdhci is a generic driver, it is helpful to see some more specific
identification of the actual hardware in dmesg. PCI vendor, device and
revision is sufficient in most cases.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
A base clock value of 0 means that the driver must get the base clock through
some other means. As we have no other way of getting it, we must abort.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The MMC specification allows non-power of two block sizes. As such,
we should not pass the log2 block size to host drivers, but instead
pass the byte size.
However, ARM MMCI can only work with log2 block size, so continue to
pass both the log2 block size and byte block size. This means that
for the moment, the byte block size must remain a power of two, but
this is the first stage of removing this restriction for other hosts.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
On 64-bit machines, we just lost the uppermost 32 bits.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Rather than having every driver duplicate the set_ios debugging,
provide a single version in mmc.c which can be expanded as we
add additional functionality.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Rather than each driver test MMC_DEBUG itself, and define DEBUG,
pass it in via the makefile instead.
Fix drivers to use pr_debug() where appropriate, and avoid defining
a DEBUG() macro.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Driver for the Secure Digital Host Controller Interface specification.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
David Howells
Pierre Ossman
Russell King
Linus Torvalds
Thomas Gleixner
Andrew Morton