Many struct file_operations in the kernel can be "const". Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data. In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ELAN's U132 is a USB to CardBus OHCI controller adapter,
designed specifically for CardBus 3G data cards to
function in machines without a CardBus slot.
The "ftdi-elan" module is a USB client driver, that detects
a supported CardBus OHCI controller plugged into the
U132 adapter and thereafter provides the conduit for
for access by the "u132-hcd" module.
The "u132-hcd" module is a (cut-down OHCI) host controller
that supports a single OHCI function of the CardBus
card inserted into the U132 adapter.
The problem with the initial implementation is that when
the CardBus card inserted into the U132 adapter has multiple
functions (and a CardBus card can support up to 4 functions),
it was the first function that was arbitrarily choosen.
The first batch of 3G cards tested, like the Merlin Qualcomm
V620, have two functions each supporting a seperate USB OHCI
host controller, of which it was that first function that is
wired up to the 3G modem.
Then along comes the Vodafone Mobile Connect 3G/GPRS data card,
aka "Option GT 3G Quad" as printed on it's rear or "Option N.V.
GlobeTrotter Fusion Quad Lite" as read with "lspci -v". And it
has the meaningful functionality in the second CardBus function.
That presents a problem because it was the "ftdi-elan" module
alone that knows how to communicate to the embedded CardBus slot
and the "u132-hcd" module alone that knows how to access the
pcmcia configuration and CardBus accessible memory space. And
of course, the information about attached (internally hardwired)
devices is contained within USB configuration embedded somewhere
within the CardBus card.
If only the "u132-hcd" module probe() interface could return a
result code that propagated back to the instigating function
platform_device_register() then the "ftdi-elan" module could
try an alternative CardBus function. However in spite of
the recent changes to the drivers/base/ routines that moved
device_attach() from bus_add_device() to bus_attach_device()
both of those routines lose the "failed to attach" 0 result
code and thus the calling routine, namely device_add() is
incapable of propaging the "failed to attach" condition back
to platform_device_add() and consequently back to the caller
of platform_device_register()
Experiments show that patching bus_attach_device() to return
ENODEV fails with the kernel locking up very early during
boot. But, however, if the patch is restricted to calls from
platform_device_add() then it does seem to work.
Unfortunately, until the kernel's drivers/base is properly
modified to propagate -ENODEV back to the caller of
platform_device_register(), it is necessary to "fix" the
"ftdi-elan" module by importing knowledge from the
"u132-hcd" module. This is the reason for the duplicated
functionality introduced in this patch.
Signed-off-by: Tony Olech <tony.olech@elandigitalsystems.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Conflicts:
drivers/infiniband/core/iwcm.c
drivers/net/chelsio/cxgb2.c
drivers/net/wireless/bcm43xx/bcm43xx_main.c
drivers/net/wireless/prism54/islpci_eth.c
drivers/usb/core/hub.h
drivers/usb/input/hid-core.c
net/core/netpoll.c
Fix up merge failures with Linus's head and fix new compilation failures.
Signed-Off-By: David Howells <dhowells@redhat.com>
This patch contains the following possible cleanups:
- make the needlessly global ftdi_release_platform_dev() static
- remove the unused usb_ftdi_elan_read_reg()
- proper prototypes for the following functions:
- usb_ftdi_elan_read_pcimem()
- usb_ftdi_elan_write_pcimem()
Note that the misplaced prototypes for the latter ones in
drivers/usb/host/u132-hcd.c were buggy. Depending on the calling
convention of the architecture calling one of them could have turned
your stack into garbage.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Deleted some unused code that could do bad things on non-x86 platforms.
Also fixed some minor formatting errors.
Thanks to Al Viro for pointing out the sparse errors.
Cc: Tony Olech <tony.olech@elandigitalsystems.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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 "ftdi-elan" module is one half of the "driver" for
ELAN's Uxxx series adapters which are USB to PCMCIA CardBus
adapters. Currently only the U132 adapter is available and
it's module is called "u132-hcd".
When the USB hot plug subsystem detects a Uxxx series adapter
it should load this module.
Upon a successful device probe() the jtag device file interface
is created and the status workqueue started up.
The jtag device file interface exists for the purpose of
updating the firmware in the Uxxx series adapter, but as
yet it had never been used.
The status workqueue initializes the Uxxx and then sits there
polling the Uxxx until a supported PCMCIA CardBus device is
detected it will start the command and respond workqueues
and then load the module that handles the device. This will
initially be only the u132-hcd module. The status workqueue
then just polls the Uxxx looking for card ejects.
The command and respond workqueues implement a command
sequencer for communicating with the firmware on the other
side of the FTDI chip in the Uxxx. This "ftdi-elan" module
exports some functions to interface with the sequencer.
Note that this module is a USB client driver.
Note that the "u132-hcd" module is a (cut-down OHCI)
host controller.
Thus we have a topology with the parent of a host controller
being a USB client! This really stresses the USB subsystem
semaphore/mutex handling in the module removal.
Signed-off-by: Tony Olech <tony.olech@elandigitalsystems.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Cyrill Gorcunov