XHCI debug capability (DbC) is an optional but standalone
functionality provided by an xHCI host controller. Software
learns this capability by walking through the extended
capability list of the host. XHCI specification describes
DbC in section 7.6.
This patch introduces the code to probe and initialize the
debug capability hardware during early boot. With hardware
initialized, the debug target (system on which this code is
running) will present a debug device through the debug port
(normally the first USB3 port). The debug device is fully
compliant with the USB framework and provides the equivalent
of a very high performance (USB3) full-duplex serial link
between the debug host and target. The DbC functionality is
independent of the xHCI host. There isn't any precondition
from the xHCI host side for the DbC to work.
One use for this feature is kernel debugging, for example
when your machine crashes very early before the regular
console code is initialized. Other uses include simpler,
lockless logging instead of a full-blown printk console
driver and klogd.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathias Nyman <mathias.nyman@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-usb@vger.kernel.org
Link: http://lkml.kernel.org/r/1490083293-3792-3-git-send-email-baolu.lu@linux.intel.com
[ Small fix to the Kconfig help text. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Remove this line of code because devnum is overwritten before it can be used.
This could happen if line of code 609 (goto try_again;) is executed. Otherwise,
devnum is never used again.
Addresses-Coverity-ID: 1226870
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Kernel source files need not include <linux/kconfig.h> explicitly
because the top Makefile forces to include it with:
-include $(srctree)/include/linux/kconfig.h
This commit removes explicit includes except the following:
* arch/s390/include/asm/facilities_src.h
* tools/testing/radix-tree/linux/kernel.h
These two are used for host programs.
Link: http://lkml.kernel.org/r/1473656164-11929-1-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The Kconfig currently controlling compilation of this code is:
arch/x86/Kconfig.debug:config EARLY_PRINTK_DBGP
arch/x86/Kconfig.debug: bool "Early printk via EHCI debug port"
...meaning that it currently is not being built as a module by anyone.
Lets remove the couple traces of modularity so that when reading the
driver there is no doubt it is builtin-only.
Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We can only reach this spot by breaking out of the scan loop,
so by construction ret > 0.
Found by Coverity, in a copy of this file in the Xen sources.
Signed-off-by: Tim Deegan <tim@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Relax condition of building the reset interface stubs in
drivers/usb/early/ehci-dbgp.c from USB_EHCI_HCD to just USB, to also
cover the chipidea driver re-using code from ehci-hcd.
Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since there's no possible caller of dbgp_external_startup() and
dbgp_reset_prep() when !USB_EHCI_HCD, there's no point in building and
exporting these functions in that case. This eliminates a build error
under the conditions listed in the subject, introduced with the merge
f1c6872e49.
Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Just like for the in-tree early console debug port driver, the
hypervisor - when using a debug port based console - also needs to be
told about controller resets, so it can suppress using and then
re-initialize the debug port accordingly.
Other than the in-tree driver, the hypervisor driver actually cares
about doing this only for the device where the debug is port actually
in use, i.e. it needs to be told the coordinates of the device being
reset (quite obviously, leveraging the addition done for that would
likely benefit the in-tree driver too).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb-dbgp - increase the controller wait time to come out of halt.
kdb - Remove unused KDB_FLAG_ONLY_DO_DUMP code and cpu in more prompt
debug core - pass NMI type on archs that provide NMI types
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (GNU/Linux)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=LAWq
-----END PGP SIGNATURE-----
Merge tag 'for_linux-3.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb
Pull KGDB/KDB/usb-dbgp fixes and cleanups from Jason Wessel:
"There are no new features, those will be delayed to the 3.7 window.
There are only fixes/cleanup against the usual kernel churn and we are
removing more lines than we add:
- usb-dbgp - increase the controller wait time to come out of halt.
- kdb - Remove unused KDB_FLAG_ONLY_DO_DUMP code and cpu in more prompt
- debug core - pass NMI type on archs that provide NMI types"
* tag 'for_linux-3.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb:
USB: echi-dbgp: increase the controller wait time to come out of halt.
kernel/debug: Make use of KGDB_REASON_NMI
kdb: Remove cpu from the more prompt
kdb: Remove unused KDB_FLAG_ONLY_DO_DUMP
The default 10 microsecond delay for the controller to come out of
halt in dbgp_ehci_startup is too short, so increase it to 1 millisecond.
This is based on emperical testing on various USB debug ports on
modern machines such as a Lenovo X220i and an Ivybridge development
platform that needed to wait ~450-950 microseconds.
Cc: <stable@vger.kernel.org>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Fixed a space issue relating to ":" operator found
by checkpatch.pl tool in drivers/usb/early/ehci-dbgp.c
Signed-off-by: Jeffrin Jose <ahiliation@yahoo.co.in>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The two first HC capability registers (CAPLENGTH and HCIVERSION)
are defined as one 8-bit and one 16-bit register. Most HC
implementations have selected to treat these registers as part
of a 32-bit register, giving the same layout for both big and
small endian systems.
This patch adds a new quirk, big_endian_capbase, to support
controllers with big endian register interfaces that treat
HCIVERSION and CAPLENGTH as individual registers.
Signed-off-by: Jan Andersson <jan@gaisler.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
For all modules, change <module>-objs to <module>-y; remove
if-statements and replace with lists using the kbuild idiom; move
flags to the top of the file; and fix alignment while trying to
maintain the original scheme in each file.
None of the dependencies are modified.
Signed-off-by: matt mooney <mfm@muteddisk.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch adds the capability to use the usb debug port with the
kernel debugger. It is also still possible to use this functionality
with or without the earlyprintk=dbgpX. It is possible to use the
kgdbwait boot argument to debug very early in the kernel start up code.
There are two ways to use this driver extension with a kernel boot argument.
1) kgdbdbgp=# -- Where # is the number of the usb debug controller
You must use sysrq-g to break into the kernel debugger on another
connection type other than the dbgp.
2) kgdbdbgp=#debugControlNum#,#Seconds#
In this mode, the usb debug port is polled every #Seconds# for
character input. It is possible to use gdb or press control-c to
break into the kernel debugger.
From the implementation perspective there are 3 high level changes.
1) Allow variable retries for the the hardware via dbgp_bulk_read().
The amount of retries for the dbgp_bulk_read() needed to be
variable instead of fixed. We do not want to poll at all when the
kernel is operating in interrupt driven mode. The polling only
occurs if the kernel was booted when specifying some number of
seconds via the kgdbdbgp boot argument (IE kgdbdbgp=0,1). In this
case the loop count is reduced to 1 so as introduce the smallest
amount of latency as possible.
2) Save the bulk IN endpoint address for use by the kgdb code.
3) The addition of the kgdb interface code.
This consisted of adding in a character read function for the dbgp
as well as a polling thread to allow the dbgp to interrupt the
kernel execution. The rest is the typical kgdb I/O api.
CC: Eric Biederman <ebiederm@xmission.com>
CC: Yinghai Lu <yhlu.kernel@gmail.com>
CC: linux-usb@vger.kernel.org
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch addresses two problems:
1) Bulk reads should always use the DATA0 for the pid, and the write
PID should toggle between DATA0 and DATA1. The fix is using
dbgp_pid_write_update() and dbgp_pid_read_update().
2) The delay loop for waiting for a transaction was not long enough to
always complete the initial handshake inside dbgp_wait_until_done().
After the initial handshake the maximum delay length is never reached.
The combined result of these two changes allows for the removal of the
forced resynchronization where a bulk write was issued with a dummy
data payload only to get the device to start accepting data writes
again.
CC: Eric Biederman <ebiederm@xmission.com>
CC: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Commit 917778267f removed __init from
ehci_wait_for_port(), but left it in place on ehci_reset_port(), which
is being called from the former function.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
On some EHCI debug controllers after the host controller driver is
activated, the debug controller will occasionally fail to submit a
bulk write URB. On controllers that exhibit this behavior a dummy
bulk write must get submitted to resynchronize the device.
The "dummy bulk write" does not get received by the host attached to
the other end of the usb debug device. The usb debug device simply
acknowledges the "dummy bulk write" and returns to a usable state.
The behavior, without this patch is that you see missing text from a
complete kernel boot when using the keep option to the earlyprintk
kernel argument.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
On some EHCI usb debug controllers, the EHCI debug device will fail to
be seen after a port reset, after a warm reset. Two options exist to
get the device to initialize correctly.
Option 1 is to unplug and plug in the device.
Option 2 is to use the EHCI port test to get the usb debug device to
start talking again. At that point the debug controller port reset
will succeed.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
CC: dbrownell@users.sourceforge.net
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
If the EHCI debug port is initialized and in use, the EHCI host
controller driver must follow two rules.
1) If the EHCI host driver issues a controller reset, the debug
controller driver re-initialization must get called after the reset
is completed.
2) The EHCI host driver should ignore any requests to the physical
EHCI debug port when the EHCI debug port is in use.
The code to check for the debug port was moved from ehci_pci_reinit()
to ehci_pci_setup because it must get called prior to ehci_reset()
which will clear the debug port registers.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: dbrownell@users.sourceforge.net
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch implements several changes:
1) Improve the capability to debug the dbgp driver
The dbgp_ehci_status() was added in a number of places to report
the critical ehci registers to diagnose the cause of a failure of
the ehci-dbgp driver.
2) Capability to survive the host controller initialization
The dbgp_external_startup(), dbgp_not_safe, and dbgp_phys_port were
added so as to allow the ehci-dbgp to re-initialize after the ehci
host controller is reset by the standard host controller driver.
This same routine is common for the early startup or
re-initialization.
This resulted in the need to move some of the initialization code
out of the __init section because the ehci driver has the
possibility to be loaded later on as a kernel module.
3) Stability improvements for device initialization
The device enumeration from 0 to 127 has the possibility to fail
the first time after a warm reset on some older EHCI debug
controllers. The enumeration will be tried up to 3 times to
account for this failure case.
The dbg_wait_until_complete() was changed to wait up to 250 ms
before failing which only comes into play during device
initialization. The maximum delay will never get hit during the
course of normal operation of the driver, unless the device got
unplugged or there was a ehci controller failure, in which case the
dbgp device driver will shut itself down.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: dbrownell@users.sourceforge.net
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When using the EHCI host controller as a polled device, a bit more
tolerance is required in terms of delays. On some 3+ghz systems the
cpu loops were faster than the EHCI device mmio and resulted in the
controller failing to initialize.
On at least one first generation EHCI controller when it was not
operating in interrupt mode, it would fail to report a port change
status, but executing the port reset allowed the debug controller to
work correctly anyway. This errata causes a one time 300ms delay in
the boot time, where as the typical delay is 1-5ms for an EHCI
controller that does not have this errata.
The debug printk's were fixed to have the correct state messages, and
there was a conversion from using early_printk to printk to avoid
calling the dbgp driver while debugging the initialization.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The PCI quirk code executes a BIOS hand off to obtain full control of
the EHCI host controller, the self contained ehci-dbgp driver must do
the same thing using the early PCI API, else the BIOS can cause a
fatal fault.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: dbrownell@users.sourceforge.net
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The rs232 drivers send a carriage return prior to a new line in the
early printk code.
The usb debug driver should do the same because you want to be able to
use the same terminal programs and tools for analysis of early printk
data.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Move the dbgp early printk driver in advance of refactoring and adding
new code, so the changes to this code are tracked separately from the
move of the code.
The drivers/usb/early directory will be the location of the current
and future early usb code for driving usb devices prior initializing
the standard interrupt driven USB drivers.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Lu Baolu