Ensure correct probing and pass though important configuration
options to the AB8500 CODEC driver when DT is enabled
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This patch contains a couple of general MSP clean-ups pertaining to
layout changes and changing functions to be void instead of int instead
of regardlessly returning '0'.
Acked-by: Ola Lilja <ola.o.lilja@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
There are four SDIs on the HREF, as opposed to the original two
enabled on Snowball. To get them working we have to pass their DMA
information in the same was as we need with the other two.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Here we add three nodes enabling UART support on the HREF hardware
reference board.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
First commit applying the new Device Tree for ST-Ericsson's u8500
based hardware reference board.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Since initial support was provided for the Nomadik I2C driver, it
has been converted to an AMBA device. AMBA devices are probed in
a slightly different way to other devices, so we have to identify
them using an "arm,primecell" compatible string. As well as doing
just that, this patch specifies which regulators the controller
should use and requests a clock-speed. The latter is provided as
more of an example, as it's the same as the recently changed
default configuration.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
All AB8500 devices are now registered via MFD core, so Device Tree
capability is no longer required for probing. Here we pull the DT
match table to ensure we're no longer probed during Device Tree
start-up.
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: rtc-linux@googlegroups.com
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
The compatible string found in the Power-On-Key's MFD cell matches
the device name provided in the driver. Keeping this naming convention
seems like a good idea, so we're changing the one found in the DTS
file to match.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This was left over during a recent clean-up which removed Device Tree
helper structs. There is no longer a requirement for it, so we can just
remove it.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This reverts commit ca3b3faf9b.
There was a plan to place ab8500_irq_get_virq() calls in each AB8500
child device prior to requesting an IRQ, but as we're no longer using
Device Tree to collect our IRQ numbers, it's actually better to allow
the core to do this during device registration time. So the IRQ number
we pull from its resource has already been converted to a virtual IRQ.
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
It's understood that the AB8500 should be subordinate to the DB8500;
however, the AB8500 uses the GIC as it's interrupt controller. If
we do not specify which IRQ controller to use the default is to use
the next encountered IRQ controller as we climb the tree. This would
be the DB8500. This patch ensures the AB8500 makes use of the correct
interrupt controller.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
We're just about to provide the DB8500-PRCMU with its own IRQ domain,
so that its subordinate drivers can use it as an interrupt controller.
It's obligatory for all IRQ controllers to reference themselves as
such from its own node in Device Tree. This patch does just that.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
of_irq_find_parent is a handy function to use outside the confines of
the Open Firmware subsystem. One such use-case is when the IRQ Domain
wishes to find an IRQ domain for a given device node. Currently it can
not take any notice of the 'interrupt-parent' property. Instead it
just uses the first IRQ controller as it climbs the Device Tree. If
we were to use this as a precursor the resultant controller is more
likely to be correct.
Acked-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Here we document the AB8500 Audio CODEC in the existing MFD AB8500 document.
CC: alsa-devel@alsa-project.org
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
When booting with Device Tree we need a way to call-back to the
DB8500 PMU IRQ handler. This is necessary because the two CPU
IRQ lines are muxed together on the DB8500 chip. The DB8500
PMU IRQ handler contains logic to pass over to the other core
in the case of IRQ_NONE. This patch allows the DB8500 PMU IRQ
handler to be passed to Perf through platform data.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Here we remove some of the extra overhead we introduced to make
DT:ing the Snowball platform easier.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
'ac' essentially reconstructs the 'access' variable we already
have, except for the PFERR_PRESENT_MASK and PFERR_RSVD_MASK. As
these are not used by callees, just use 'access' directly.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Keep track of accessed/dirty bits; if they are all set, do not
enter the accessed/dirty update loop.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
'eperm' is no longer used in the walker loop, so we can eliminate it.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Instead of branchy code depending on level, gpte.ps, and mmu configuration,
prepare everything in a bitmap during mode changes and look it up during
runtime.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
The page table walk is coded as an infinite loop, with a special
case on the last pte.
Code it as an ordinary loop with a termination condition on the last
pte (large page or walk length exhausted), and put the last pte handling
code after the loop where it belongs.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
walk_addr_generic() permission checks are a maze of branchy code, which is
performed four times per lookup. It depends on the type of access, efer.nxe,
cr0.wp, cr4.smep, and in the near future, cr4.smap.
Optimize this away by precalculating all variants and storing them in a
bitmap. The bitmap is recalculated when rarely-changing variables change
(cr0, cr4) and is indexed by the often-changing variables (page fault error
code, pte access permissions).
The permission check is moved to the end of the loop, otherwise an SMEP
fault could be reported as a false positive, when PDE.U=1 but PTE.U=0.
Noted by Xiao Guangrong.
The result is short, branch-free code.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
While unspecified, the behaviour of Intel processors is to first
perform the page table walk, then, if the walk was successful, to
atomically update the accessed and dirty bits of walked paging elements.
While we are not required to follow this exactly, doing so will allow us
to perform the access permissions check after the walk is complete, rather
than after each walk step.
(the tricky case is SMEP: a zero in any pte's U bit makes the referenced
page a supervisor page, so we can't fault on a one bit during the walk
itself).
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
We no longer rely on paging_tmpl.h defines; so we can move the function
to mmu.c.
Rely on zero extension to 64 bits to get the correct nx behaviour.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
If nx is disabled, then is gpte[63] is set we will hit a reserved
bit set fault before checking permissions; so we can ignore the
setting of efer.nxe.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
gpte_access() computes the access permissions of a guest pte and also
write-protects clean gptes. This is wrong when we are servicing a
write fault (since we'll be setting the dirty bit momentarily) but
correct when instantiating a speculative spte, or when servicing a
read fault (since we'll want to trap a following write in order to
set the dirty bit).
It doesn't seem to hurt in practice, but in order to make the code
readable, push the write protection out of gpte_access() and into
a new protect_clean_gpte() which is called explicitly when needed.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This change makes it so that the VF can support the PF/VF API negotiation
protocol. Specifically in this case we are adding support for API 1.0
which will mean that the VF is capable of cleaning up buffers that span
multiple descriptors without triggering an error.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Sibai Li <sibai.li@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Current implementation enables EEE on only i350 device. This patch enables
EEE on all eee_supported devices. Also, configured LPI clock to keep
running before EEE is enabled on i210 and i211 devices.
Signed-off-by: Akeem G. Abodunrin <akeem.g.abodunrin@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
For some reason the reading of the RQDPC register was being artificially
limited to 4K. Instead of limiting the value we should read the value and
add the full amount. Otherwise this can lead to a misleading number of
dropped packets when the actual value is in fact much higher.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
While going through Ubuntu bugs, I discovered this patch being
posted and a confirmation that the patch works as expected.
Finding out how the hw volume really works would be preferrable
to just disabling the broken one, but this would be better than
nothing.
Credit: sndfnsdfin (qawsnews)
BugLink: https://bugs.launchpad.net/bugs/559939
Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
In the IBSS auth TX debug message the BSSID and DA
address are reversed, fix that.
Signed-off-by: Sylvain Roger Rieunier <sylvain.roger.rieunier@gmail.com>
[reword commit message and make it fit 72 cols]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Here we add the required documentation for the new Device Tree
bindings pertaining to the MSP CPU-side DAI Driver.
Acked-by: Ola Lilja <ola.o.lilja@stericsson.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Here we add the required documentation for the new Device Tree
bindings pertaining to the MOP500 Audio Machine driver.
Acked-by: Ola Lilja <ola.o.lilja@stericsson.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Includes removal of duplicate debug print affirming entry into
the probe function, an unnecessary line break of a coding line
<80 chars and a white space change (unintentional tab).
Acked-by: Ola Lilja <ola.o.lilja@stericsson.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
We continue to allow the AB8500 CODEC to be registered via the AB8500
Multi Functional Device API, only this time we extract its configuration
from the Device Tree binary.
Acked-by: Ola Lilja <ola.o.lilja@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Register both parts of the MSP driver from Device Tree so that they
are probed when Device Tree is enabled. Also, as there is platform
data involved, we ensure that there is allocated memory to place the
configuration into and that the correct information is extracted from
the DT binary.
Acked-by: Ola Lilja <ola.o.lilja@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Here we ensure that the MOP500 audio driver will be probed during a
Device Tree boot. We also parse the sound node to link together the
codec, dma and the CPU-side Digital Audio Interface.
Acked-by: Ola Lilja <ola.o.lilja@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
In the initial submission of the MSP driver msp1 and msp3's associated
pinctrl mechanism was passed back to platform code using a plat_init()
call-back routine, but it has no place in platform code. The MSP driver
should set this up for the appropriate ports. Instead we use a use_pinctrl
identifier which is passed from platform_data/Device Tree which indicates
which ports should use pinctrl.
Acked-by: Ola Lilja <ola.o.lilja@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Instead of having to duplicate the description of the properties needed
for interrupt support, reference the new standard document.
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: devicetree-discuss@lists.ozlabs.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
[Minor spelling correction]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
In ext4_nonda_switch(), if the file system is getting full we used to
call writeback_inodes_sb_if_idle(). The problem is that we can be
holding i_mutex already, and this causes a potential deadlock when
writeback_inodes_sb_if_idle() when it tries to take s_umount. (See
lockdep output below).
As it turns out we don't need need to hold s_umount; the fact that we
are in the middle of the write(2) system call will keep the superblock
pinned. Unfortunately writeback_inodes_sb() checks to make sure
s_umount is taken, and the VFS uses a different mechanism for making
sure the file system doesn't get unmounted out from under us. The
simplest way of dealing with this is to just simply grab s_umount
using a trylock, and skip kicking the writeback flusher thread in the
very unlikely case that we can't take a read lock on s_umount without
blocking.
Also, we now check the cirteria for kicking the writeback thread
before we decide to whether to fall back to non-delayed writeback, so
if there are any outstanding delayed allocation writes, we try to get
them resolved as soon as possible.
[ INFO: possible circular locking dependency detected ]
3.6.0-rc1-00042-gce894ca #367 Not tainted
-------------------------------------------------------
dd/8298 is trying to acquire lock:
(&type->s_umount_key#18){++++..}, at: [<c02277d4>] writeback_inodes_sb_if_idle+0x28/0x46
but task is already holding lock:
(&sb->s_type->i_mutex_key#8){+.+...}, at: [<c01ddcce>] generic_file_aio_write+0x5f/0xd3
which lock already depends on the new lock.
2 locks held by dd/8298:
#0: (sb_writers#2){.+.+.+}, at: [<c01ddcc5>] generic_file_aio_write+0x56/0xd3
#1: (&sb->s_type->i_mutex_key#8){+.+...}, at: [<c01ddcce>] generic_file_aio_write+0x5f/0xd3
stack backtrace:
Pid: 8298, comm: dd Not tainted 3.6.0-rc1-00042-gce894ca #367
Call Trace:
[<c015b79c>] ? console_unlock+0x345/0x372
[<c06d62a1>] print_circular_bug+0x190/0x19d
[<c019906c>] __lock_acquire+0x86d/0xb6c
[<c01999db>] ? mark_held_locks+0x5c/0x7b
[<c0199724>] lock_acquire+0x66/0xb9
[<c02277d4>] ? writeback_inodes_sb_if_idle+0x28/0x46
[<c06db935>] down_read+0x28/0x58
[<c02277d4>] ? writeback_inodes_sb_if_idle+0x28/0x46
[<c02277d4>] writeback_inodes_sb_if_idle+0x28/0x46
[<c026f3b2>] ext4_nonda_switch+0xe1/0xf4
[<c0271ece>] ext4_da_write_begin+0x27/0x193
[<c01dcdb0>] generic_file_buffered_write+0xc8/0x1bb
[<c01ddc47>] __generic_file_aio_write+0x1dd/0x205
[<c01ddce7>] generic_file_aio_write+0x78/0xd3
[<c026d336>] ext4_file_write+0x480/0x4a6
[<c0198c1d>] ? __lock_acquire+0x41e/0xb6c
[<c0180944>] ? sched_clock_cpu+0x11a/0x13e
[<c01967e9>] ? trace_hardirqs_off+0xb/0xd
[<c018099f>] ? local_clock+0x37/0x4e
[<c0209f2c>] do_sync_write+0x67/0x9d
[<c0209ec5>] ? wait_on_retry_sync_kiocb+0x44/0x44
[<c020a7b9>] vfs_write+0x7b/0xe6
[<c020a9a6>] sys_write+0x3b/0x64
[<c06dd4bd>] syscall_call+0x7/0xb
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
Add myself as the maintainer for the BCM2835 ARM support, and related
drivers. This is mainly so that the MAINTAINERS file contains some
relevant entry, and the rpi/ARM mailing lists; I'd be quite happy if
anyone else came along and wanted to maintain/co-maintain this.
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
This patch was extracted from git://github.com/lp0/linux.git branch
rpi-split as of 2012/09/08, and modified as follows:
* s/bcm2708/bcm2835/.
* Modified device tree vendor prefix.
* Modified UART DT node to use a unit-address to create unique UART node
names, rather than using non-type names "uart0" and "uart1".
Note that UART 1 (the Broadcom "mini UART") is not yet present, but
I'm naming the DT node in anticipation that it will be added.
Signed-off-by: Chris Boot <bootc@bootc.net>
Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: Dom Cobley <popcornmix@gmail.com>
Signed-off-by: Dom Cobley <dc4@broadcom.com>
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
This patch adds a minimal stub clock driver for the BCM2835. Its sole
purpose is to allow the PL011 AMBA clk_get() API calls to provide
something that looks enough like a clock that the driver probes and
operates correctly.
This patch was extracted from git://github.com/lp0/linux.git branch
rpi-split as of 2012/09/08, and modified as follows:
* Reworked to call clk_register_fixed_rate(), and clk_register_clkdev()
rather than using static data to represent the clocks.
* Moved implementation to drivers/clk/.
* Modified .dev_id for UART clocks to match UART DT node names.
* s/bcm2708/bcm2835/.
* Modified device tree vendor prefix.
Signed-off-by: Chris Boot <bootc@bootc.net>
Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: Dom Cobley <popcornmix@gmail.com>
Signed-off-by: Dom Cobley <dc4@broadcom.com>
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Mike Turquette <mturquette@linaro.org>
The System Timer peripheral provides four 32-bit timer channels and a
single 64-bit free running counter. Each channel has an output compare
register, which is compared against the 32 least significant bits of the
free running counter values, and generates an interrupt.
Timer 3 is used as the Linux timer.
The BCM2835 also contains an SP804-based timer module. However, it
apparently has significant differences from the standard SP804 IP block,
and Broadcom's documentation recommends using the system timer instead.
This patch was extracted from git://github.com/lp0/linux.git branch
rpi-split as of 2012/09/08, and modified as follows:
* s/bcm2708/bcm2835/.
* Modified device tree vendor prefix.
* Moved to drivers/clocksource/. This looks like the desired location for
such code now.
* Added DT binding docs.
* Moved struct sys_timer bcm2835_timer into time.c to encapsulate it more.
* Simplified bcm2835_time_init() to find one matching node and operate on
it, rather than looping over all matching nodes. This seems more
consistent with other clocksource code.
* Simplified bcm2835_time_init() using of_iomap().
* Renamed struct bcm2835_timer.index to match_mask to better represent its
purpose.
* s/printk(PR_INFO/pr_info(/
Signed-off-by: Chris Boot <bootc@bootc.net>
Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: Dom Cobley <popcornmix@gmail.com>
Signed-off-by: Dom Cobley <dc4@broadcom.com>
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
The BCM2835 contains a custom interrupt controller, which supports 72
interrupt sources using a 2-level register scheme. The interrupt
controller, or the HW block containing it, is referred to occasionally
as "armctrl" in the SoC documentation, hence the symbol naming in the
code.
This patch was extracted from git://github.com/lp0/linux.git branch
rpi-split as of 2012/09/08, and modified as follows:
* s/bcm2708/bcm2835/.
* Modified device tree vendor prefix.
* Moved implementation to drivers/irchip/.
* Added devicetree documentation, and hence removed list of IRQs from
bcm2835.dtsi.
* Changed shift in MAKE_HWIRQ() and HWIRQ_BANK() from 8 to 5 to reduce
the size of the hwirq space, and pass the total size of the hwirq space
to irq_domain_add_linear(), rather than just the number of valid hwirqs;
the two are different due to the hwirq space being sparse.
* Added the interrupt controller DT node to the top-level of the DT,
rather than nesting it inside a /axi node. Hence, changed the reg value
since /axi had a ranges property. This seems simpler to me, but I'm not
sure if everyone will like this change or not.
* Don't set struct irq_domain_ops.map = irq_domain_simple_map, hence
removing the need to patch include/linux/irqdomain.h or
kernel/irq/irqdomain.c.
* Simplified armctrl_of_init() using of_iomap().
* Removed unused IS_VALID_BANK()/IS_VALID_IRQ() macros.
* Renamed armctrl_handle_irq() to prevent possible symbol clashes.
* Made armctrl_of_init() static.
* Removed comment "Each bank is registered as a separate interrupt
controller" since this is no longer true.
* Removed FSF address from license header.
* Added my name to copyright header.
Signed-off-by: Chris Boot <bootc@bootc.net>
Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: Dom Cobley <popcornmix@gmail.com>
Signed-off-by: Dom Cobley <dc4@broadcom.com>
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
The BCM2835 is an ARM SoC from Broadcom. This patch adds very basic
support for this SoC.
http://www.broadcom.com/products/BCM2835http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf
Note that the documentation in the latter .pdf assumes the MMU setup
that's used on the "VideoCore" companion processor, and does not document
physical peripheral addresses. Subtract 0x5e000000 to obtain the physical
addresses. This is accounted for by the ranges property in the /soc node
in the device tree.
The BCM2835 SoC is used in the Raspberry Pi. This patch also adds a
minimal device tree for this board; enough to see some very early kernel
boot messages through earlyprintk. However, this patch does not yet
provide a useful booting system.
http://www.raspberrypi.org/.
This patch was extracted from git://github.com/lp0/linux.git branch
rpi-split from 3-4 months ago, and significantly stripped down and
modified since.
Signed-off-by: Chris Boot <bootc@bootc.net>
Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: Dom Cobley <popcornmix@gmail.com>
Signed-off-by: Dom Cobley <dc4@broadcom.com>
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
The r8169 driver currently limits the DMA burst for TX to 1024 bytes. I have
a box where this prevents the interface from using the gigabit line to its full
potential. This patch solves the problem by setting TX_DMA_BURST to unlimited.
The box has an ASRock B75M motherboard with on-board RTL8168evl/8111evl
(XID 0c900880). TSO is enabled.
I used netperf (TCP_STREAM test) to measure the dependency of TX throughput
on MTU. I did it for three different values of TX_DMA_BURST ('5'=512, '6'=1024,
'7'=unlimited). This chart shows the results:
http://michich.fedorapeople.org/r8169/r8169-effects-of-TX_DMA_BURST.png
Interesting points:
- With the current DMA burst limit (1024):
- at the default MTU=1500 I get only 842 Mbit/s.
- when going from small MTU, the performance rises monotonically with
increasing MTU only up to a peak at MTU=1076 (908 MBit/s). Then there's
a sudden drop to 762 MBit/s from which the throughput rises monotonically
again with further MTU increases.
- With a smaller DMA burst limit (512):
- there's a similar peak at MTU=1076 and another one at MTU=564.
- With unlimited DMA burst:
- at the default MTU=1500 I get nice 940 Mbit/s.
- the throughput rises monotonically with increasing MTU with no strange
peaks.
Notice that the peaks occur at MTU sizes that are multiples of the DMA burst
limit plus 52. Why 52? Because:
20 (IP header) + 20 (TCP header) + 12 (TCP options) = 52
The Realtek-provided r8168 driver (v8.032.00) uses unlimited TX DMA burst too,
except for CFG_METHOD_1 where the TX DMA burst is set to 512 bytes.
CFG_METHOD_1 appears to be the oldest MAC version of "RTL8168B/8111B",
i.e. RTL_GIGA_MAC_VER_11 in r8169. Not sure if this MAC version really needs
the smaller burst limit, or if any other versions have similar requirements.
Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Acked-by: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
