linux/arch
Alexey Brodkin b607eddd71 ARCv2: guard SLC DMA ops with spinlock
SLC maintenance ops need to be serialized by software as there is no
inherent buffering / quequing of aux commands. It can silently ignore a
new aux operation if previous one is still ongoing (SLC_CTRL_BUSY)

So gaurd the SLC op using a spin lock

The spin lock doesn't seem to be contended even in heavy workloads such
as iperf. On FPGA @ 75 MHz.

 [1] Before this change:
 ============================================================
  # iperf -c 10.42.0.1
 ------------------------------------------------------------
 Client connecting to 10.42.0.1, TCP port 5001
 TCP window size: 43.8 KByte (default)
 ------------------------------------------------------------
 [  3] local 10.42.0.110 port 38935 connected with 10.42.0.1 port 5001
 [ ID] Interval       Transfer     Bandwidth
 [  3]  0.0-10.0 sec  48.4 MBytes  40.6 Mbits/sec
 ============================================================

 [2] After this change:
 ============================================================
 # iperf -c 10.42.0.1
 ------------------------------------------------------------
 Client connecting to 10.42.0.1, TCP port 5001
 TCP window size: 43.8 KByte (default)
 ------------------------------------------------------------
 [  3] local 10.42.0.243 port 60248 connected with 10.42.0.1 port 5001
 [ ID] Interval       Transfer     Bandwidth
 [  3]  0.0-10.0 sec  47.5 MBytes  39.8 Mbits/sec
 # iperf -c 10.42.0.1
 ------------------------------------------------------------
 Client connecting to 10.42.0.1, TCP port 5001
 TCP window size: 43.8 KByte (default)
 ------------------------------------------------------------
 [  3] local 10.42.0.243 port 60249 connected with 10.42.0.1 port 5001
 [ ID] Interval       Transfer     Bandwidth
 [  3]  0.0-10.0 sec  54.9 MBytes  46.0 Mbits/sec
 ============================================================

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: arc-linux-dev@synopsys.com
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2015-07-06 10:12:39 +05:30
..
alpha TTY/Serial driver patches for 4.2-rc1 2015-06-26 15:53:22 -07:00
arc ARCv2: guard SLC DMA ops with spinlock 2015-07-06 10:12:39 +05:30
arm - hwspinlock core DT support from Suman Anna 2015-07-03 14:52:25 -07:00
arm64 Various arm64 fixes: 2015-07-03 12:28:30 -07:00
avr32 Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-07-01 15:19:35 -07:00
blackfin Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
c6x Merge branch 'for-4.2/sg' of git://git.kernel.dk/linux-block 2015-06-25 15:22:36 -07:00
cris Replace module_init with equivalent device_initcall in non modules. 2015-07-02 10:30:48 -07:00
frv Fix up implicit <module.h> users that will break later. 2015-07-02 10:25:22 -07:00
h8300 h8300: Always build dtb 2015-06-23 13:36:00 +09:00
hexagon Merge branch 'for-4.2/sg' of git://git.kernel.dk/linux-block 2015-06-25 15:22:36 -07:00
ia64 remove some boot noise from a now-invalid check that pages are reserved 2015-07-02 14:46:15 -07:00
m32r Merge branch 'for-4.2/sg' of git://git.kernel.dk/linux-block 2015-06-25 15:22:36 -07:00
m68k Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-07-01 15:19:35 -07:00
metag Merge branch 'akpm' (patches from Andrew) 2015-06-26 09:52:05 -07:00
microblaze Merge branch 'for-4.2/sg' of git://git.kernel.dk/linux-block 2015-06-25 15:22:36 -07:00
mips Devicetree changes for v4.2 2015-07-01 19:40:18 -07:00
mn10300 Replace module_init with equivalent device_initcall in non modules. 2015-07-02 10:30:48 -07:00
nios2 nios2 update for v4.2 2015-07-03 12:22:49 -07:00
openrisc Merge branch 'for-4.2/sg' of git://git.kernel.dk/linux-block 2015-06-25 15:22:36 -07:00
parisc Replace module_init with equivalent device_initcall in non modules. 2015-07-02 10:30:48 -07:00
powerpc Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
s390 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
score Merge branch 'for-4.2/sg' of git://git.kernel.dk/linux-block 2015-06-25 15:22:36 -07:00
sh Replace module_init with equivalent device_initcall in non modules. 2015-07-02 10:30:48 -07:00
sparc Merge branch 'akpm' (patches from Andrew) 2015-06-26 09:52:05 -07:00
tile Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
um Minor merge needed, due to function move. 2015-07-01 10:49:25 -07:00
unicore32 arch/unicore32/kernel/fpu-ucf64.c: remove unnecessary KERN_ERR 2015-06-30 19:44:59 -07:00
x86 platform-drivers-x86 for 4.2-2 2015-07-05 10:54:09 -07:00
xtensa Replace module_init with equivalent device_initcall in non modules. 2015-07-02 10:30:48 -07:00
.gitignore
Kconfig clone: support passing tls argument via C rather than pt_regs magic 2015-06-25 17:00:38 -07:00