Real-Time patch on iMX51

AndreasOrfanos · ‎05-31-2011

Dear IMX List,

I am quite happy to post to the imx community the Linux kernel real-time patch for IMX51 Freescale SoC, version 2.6.31.12. I did some tests on IMX51 3DSTACK PDK board and wrote a small report too. Please feel free to send your comments.

imx51rt-2.6.31.12.patch.bz2

tar fx linux-2.6.31.12.tar.bz2
mkdir output
cd linux-2.6.31.12
bunzip2 -c ../imx51rt-2.6.31.12.patch.bz2 | patch -p1
make O=../output mx51rt-3dpdk_defconfig
make O=../output uImage

Kind regards

Andreas

Hedera Innovations

rajansrivastava · ‎10-31-2012

Dear Andreas,

Did you get the latency, 58us (as you mentioned in your report), right after porting the RT patch and enabling FULL_PREEMPTION, or did you do some customizations in the kernel (configuration/code)?

Thanks,

Rajan

RobertSchwebel · ‎09-17-2011

Andreas,

if you use the mainline kernel on the MX51, you can use the standard -rt patch set. MX51 is well supported in the mainline, although not as feature complete as in the FSL kernel.

Best regards,

Robert

AndreasOrfanos · ‎09-16-2011

Dear Simon,

I was quite busy this week, but I was planning to investigate the problem this weekend. Good to hear that you have made some good progress. If you have any fixes feel free to post them.

Best regards

Andreas

SimonScherzinge · ‎09-16-2011

Dear Andreas,

now, the patched linux-2.6.31.12 kernel is running on the i.MX51 evk.

I fixed the problem (last post) by deactivating the "MXC TVE TV Out Encoder".

After that, I had problems (kernel panic) with FEC and SD-Card driver.

For FEC, I fixed a bug in driver/net/fec.c and for SD-Card driver I inserted a special freescale card driver into driver/mmc.

Regards Simon

SimonScherzinge · ‎09-07-2011

Dear Andreas,

sorry for this long delay :-(.

Now I'm able to built a root filesystem for imx51evk.
I can boot my imx51 with a none realtime kernel.

But I can't boot the patched imx51 Realtime Kernel.

I did it as follow:
make ARCH=arm CROSS_COMPILE= 'HOSTCC=ccache /usr/bin/gcc -B/usr/bin/' imx51_defconfig
make ARCH=arm CROSS_COMPILE= 'HOSTCC=ccache /usr/bin/gcc -B/usr/bin/' zImage

There were three errors during build process. Therefore I changed the following:
- in arch/arm/Makefile at line 53 I changed "armv7-a" to "armv7a"
- in include/linux/regulator/machine.h at line 135 I added the variable const char *dev_name to the regulator_consumer_supply structur
- in arch/arm/mach-mx5/mx51_3stack.c at line 150 I changed "#if 0" to "#if 1" and I commented line 156 to 165 out

After successful built, I booted zImage with imx51evk and I get a Kernel panic as follow:

Uncompressing Linux............................................................................................................................
Linux version 2.6.31.12-rt21 (sischerzinger@pc574301) (gcc version 4.1.2) #24 PREEMPT RT Wed Sep 7 10:22:06 BST 2011
CPU: ARMv7 Processor [412fc085] revision 5 (ARMv7), cr=10c53c7f
CPU: VIPT nonaliasing data cache, VIPT nonaliasing instruction cache
Machine: Freescale MX51 Babbage Board
Memory policy: ECC disabled, Data cache writeback
Built 1 zonelists in Zone order, mobility grouping on. Total pages: 105664
Kernel command line: noinitrd console=ttymxc0,115200 root=/dev/nfs nfsroot=172.17.20.2:/home/sischerzinger/Reiner/IMX51RT/rootfs rw ip=dhcp panic=10
PID hash table entries: 2048 (order: 11, 8192 bytes)
Dentry cache hash table entries: 65536 (order: 6, 262144 bytes)
Inode-cache hash table entries: 32768 (order: 5, 131072 bytes)
Memory: 416MB = 416MB total
Memory: 417480KB available (3908K code, 377K data, 132K init, 0K highmem)
Real-Time Preemption Support (C) 2004-2007 Ingo Molnar
Preemptible RCU implementation.
NR_IRQS:368
MXC IRQ initialized
MXC_Early serial console at MMIO 0x73fbc000 (options '115200')
console [ttymxc0] enabled
Console: colour dummy device 80x30
Calibrating delay loop... 799.53 BogoMIPS (lpj=3997696)
Mount-cache hash table entries: 512
CPU: Testing write buffer coherency: ok
regulator: core version 0.5
NET: Registered protocol family 16
i.MX IRAM pool: 128 KB@0xda840000

IRAM READY
CPU is i.MX51 Revision 3.0
MXC GPIO hardware
iomux_config_mux: Warning: iomux pin config changed, reg=f7ea8134, prev=0x1 new=0x3
Using SDMA I.API
MXC DMA API initialized
bio: create slab <bio-0> at 0
SCSI subsystem initialized
CSPI: mxc_spi-0 probed
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
IPU DMFC NORMAL mode: 1(0~1), 5B(4,5), 5F(6,7)
Bluetooth: Core ver 2.15
NET: Registered protocol family 31
Bluetooth: HCI device and connection manager initialized
Bluetooth: HCI socket layer initialized
mc13892 Rev 2.0 FinVer 2 detected
Initializing regulators for Babbage.
regulator: SW1: 600 <--> 1375 mV
regulator: SW2: 900 <--> 1850 mV
regulator: SW3: 1100 <--> 1850 mV
regulator: SW4: 1100 <--> 1850 mV
regulator: SWBST: 0 mV
regulator: VIOHI: 0 mV
regulator: VPLL: 1050 <--> 1800 mV
regulator: VDIG: 1650 mV
regulator: VSD: 1800 <--> 3150 mV
regulator: VUSB2: 2400 <--> 2775 mV
regulator: VVIDEO: 2775 mV
regulator: VAUDIO: 2300 <--> 3000 mV
regulator: VCAM: 2500 <--> 3000 mV fast normal
regulator: VGEN1: 1200 mV
regulator: VGEN2: 1200 <--> 3150 mV
regulator: VGEN3: 1800 <--> 2900 mV
regulator: VUSB: 0 mV
regulator: GPO1: 0 mV
regulator: GPO2: 0 mV
regulator: GPO3: 0 mV
regulator: GPO4: 0 mV
Device spi1.0 probed
NET: Registered protocol family 2
IP route cache hash table entries: 4096 (order: 2, 16384 bytes)
TCP established hash table entries: 16384 (order: 5, 131072 bytes)
TCP bind hash table entries: 16384 (order: 6, 458752 bytes)
TCP: Hash tables configured (established 16384 bind 16384)
TCP reno registered
NET: Registered protocol family 1
LPMode driver module loaded
Static Power Management for Freescale i.MX51
PM driver module loaded
sdram autogating driver module loaded
Bus freq driver module loaded
DVI monitor is primary
mxc_dvfs_core_probe
mxc_dvfs_core_probe: failed to get gp regulator
DVFS driver module loaded
i.MXC CPU frequency driver
mxc_cpufreq_driver_init: failed to get gp regulator
mxc_dvfsper_probe: failed to get lp regulator
DVFS PER driver module loaded
JFFS2 version 2.2. (NAND) �© 2001-2006 Red Hat, Inc.
msgmni has been set to 815
io scheduler noop registered
io scheduler anticipatory registered
io scheduler deadline registered
io scheduler cfq registered (default)
fbcvt: 1024x768@60: CVT Name - .786M3
mxc_ipu mxc_ipu: Channel already disabled 9
mxc_ipu mxc_ipu: Channel already uninitialized 9
IPU DMFC DP HIGH RESOLUTION: 1(0,1), 5B(2~5), 5F(6,7)
Console: switching to colour frame buffer device 128x48
fbcvt: 1024x768@60: CVT Name - .786M3
regulator: get() with no identifier
Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = c0004000
[00000000] *pgd=00000000
Internal error: Oops: 805 [#1] PREEMPT
Modules linked in:
CPU: 0    Not tainted (2.6.31.12-rt21 #24)
PC is at rt_spin_lock_slowlock+0x64/0x234
LR is at clk_enable+0x20/0xa8
pc : [<c0314afc>]    lr : [<c003918c>]    psr: 60000093
sp : d8023e60 ip : f7ed4070 fp : 00000000
r10: c0425058 r9 : 00000000 r8 : 00000000
r7 : c0420120 r6 : c044a998 r5 : 60000013 r4 : c041d740
r3 : 00000000 r2 : d8022000 r1 : d8021a40 r0 : d8022000
Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel
Control: 10c5387d Table: 90004019 DAC: 00000017
Process swapper (pid: 1, stack limit = 0xd80222e8)
Stack: (0xd8023e60 to 0xd8024000)
3e60: 00000000 c0463d24 c0420128 00000000 d8022000 60000013 c044a998 c0420120
3e80: 00000000 c0314b48 c0420128 d8023e9c 00000000 c01b34e8 da80c000 c041d740
3ea0: c041d6fc c0463d80 c0420120 00000000 c0425058 c003918c 00000000 c041d784
3ec0: c041d6fc c0034258 c041cdb0 c041d784 c0420128 c003901c c041d784 c0039194
3ee0: c0420120 c0463d24 c0420128 c01b2108 c03a0ca0 c0420120 d80831b8 00000000
3f00: 00000000 00000001 c0420130 c0420128 c0436ba0 c0436ba0 c0436ba0 00000000
3f20: c043b1e0 c01d7b84 c0436ba0 c01d6dc8 c0420128 c0436ba0 c042015c c01d6ed4
3f40: 00000000 d8023f50 c01d6e74 c01d6208 d80087b0 d80315e8 d8023f54 c0436ba0
3f60: c0436ba0 d80eda60 c0017600 c01d67ac c03a0ca0 c0190ff0 c0436ba0 00000000
3f80: c044a2ac c0017600 00000000 00000000 00000000 c01d71d0 00000000 c002240c
3fa0: 00000000 c044a2ac c0017600 00000000 00000000 c00292ec c042bec8 c0079e78
3fc0: 00000000 32317c20 00000037 00000000 c002240c 00000000 00000000 00000000
3fe0: 00000000 00000000 00000000 c00086e8 00000000 c002a914 ffffffff 00000000
[<c0314afc>] (rt_spin_lock_slowlock+0x64/0x234) from [<c003918c>] (clk_enable+0x20/0xa8)
[<c003918c>] (clk_enable+0x20/0xa8) from [<c0034258>] (_clk_tve_enable+0x2c/0x54)
[<c0034258>] (_clk_tve_enable+0x2c/0x54) from [<c003901c>] (__clk_enable+0x54/0x64)
[<c003901c>] (__clk_enable+0x54/0x64) from [<c0039194>] (clk_enable+0x28/0xa8)
[<c0039194>] (clk_enable+0x28/0xa8) from [<c01b2108>] (tve_probe+0x1bc/0x408)
[<c01b2108>] (tve_probe+0x1bc/0x408) from [<c01d7b84>] (platform_drv_probe+0x1c/0x24)
[<c01d7b84>] (platform_drv_probe+0x1c/0x24) from [<c01d6dc8>] (driver_probe_device+0xb8/0x164)
[<c01d6dc8>] (driver_probe_device+0xb8/0x164) from [<c01d6ed4>] (__driver_attach+0x60/0x84)
[<c01d6ed4>] (__driver_attach+0x60/0x84) from [<c01d6208>] (bus_for_each_dev+0x48/0x80)
[<c01d6208>] (bus_for_each_dev+0x48/0x80) from [<c01d67ac>] (bus_add_driver+0xa0/0x224)
[<c01d67ac>] (bus_add_driver+0xa0/0x224) from [<c01d71d0>] (driver_register+0xac/0x134)
[<c01d71d0>] (driver_register+0xac/0x134) from [<c00292ec>] (do_one_initcall+0x5c/0x1a8)
[<c00292ec>] (do_one_initcall+0x5c/0x1a8) from [<c00086e8>] (kernel_init+0x94/0x12c)
[<c00086e8>] (kernel_init+0x94/0x12c) from [<c002a914>] (kernel_thread_exit+0x0/0x8)
Code: e3c33003 e1530001 1a000002 e3a03000 (e5833000)
---[ end trace da227214a82491b7 ]---
note: swapper[1] exited with preempt_count 1
Kernel panic - not syncing: Attempted to kill init!

I'm looking after this problem for a while.
Do you have any experience for this error?
Do you have a proposal how to fix this Kernel panic?

Regards Simon

Andreas Orfanos said:

Dear Simon,
Good to hear that you have managed to build the Linux kernel with Real-Time support successfully
If you need to build distros, one of the ways to do it is to use Yokto project, or openEmbedded.
There is a long learning curve to go in order to start working with those distro build platforms, but it is the mainstream and the way forward.
Please see links below:
http://www.yoctoproject.org/

Regards,
Andreas

AndreasOrfanos · ‎07-20-2011

Dear Simon,

Good to hear that you have managed to build the Linux kernel with Real-Time support successfully

If you need to build distros, one of the ways to do it is to use Yokto project, or openEmbedded.
There is a long learning curve to go in order to start working with those distro build platforms, but it is the mainstream and the way forward.
Please see links below:
http://www.yoctoproject.org/

Regards,

Andreas

SimonScherzinge · ‎07-18-2011

Dear Andreas,

The build process with
make ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- O=../output uImage
was successful. Thank you.

Now, I want to run that Kernel Image on the imx51 EVK.

Do I need also a root filesystem, with bin, lib, dev, ...?
Is there a way to build such a root filesystem?

In the past I used ltib (Linux Target Image Builder) to build the Board Support Package.
Ltib generated a rootfs directory, which contained for example the uImage and kernel modules which I did by myself.
The imx51 EVK was able to boot and work with this rootfs directory.

Now, I think I have to create the same environment with your patched linux-2.6.31.12 rt-kernel to be successful.
How can I do this?
Which is the best way?

I would be glad, if you can help a second time.

Regards Simon

AndreasOrfanos · ‎07-11-2011

Dear Simon,

Please try the toolchain IA32 GNU/Linux TAR from http://www.codesourcery.com/sgpp/lite/arm/portal/release1294

Follow the instructions how to install it from the codesourcery web site and then try:

make ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- O=../output uImage

Regards,

Andreas

Simon Scherzinger said:

Dear Andreas,

your post sounds great.
I want to try the same, but I use the imx51 EVK.
Therefore, I configured the kernel with imx51_defconfig except of mx51rt-3dpdk_defconfig.
After that I start to build the kernel with
make ARCH=arm CROSS_COMPILE= 'HOSTCC=ccache /usr/bin/gcc -B/usr/bin/' O=../output uImage
But than occurs the following errors:
cc1: error: unrecognized command line option "-mlittle-endian"
cc1: error: unrecognized command line option "-mabi=aapcs-linux"
cc1: error: unrecognized command line option "-mno-thumb-interwork"

Or is there an other way to build a real-time system for imx51 EVK?
I'm new in this subject, so it would be very nice, if you can help me.

Regards
Simon

SimonScherzinge · ‎07-11-2011

Dear Andreas,

your post sounds great.

I want to try the same, but I use the imx51 EVK.

Therefore, I configured the kernel with imx51_defconfig except of mx51rt-3dpdk_defconfig.

After that I start to build the kernel with

make ARCH=arm CROSS_COMPILE= 'HOSTCC=ccache /usr/bin/gcc -B/usr/bin/' O=../output uImage

But than occurs the following errors:

cc1: error: unrecognized command line option "-mlittle-endian"
cc1: error: unrecognized command line option "-mabi=aapcs-linux"
cc1: error: unrecognized command line option "-mno-thumb-interwork"

Or is there an other way to build a real-time system for imx51 EVK?

I'm new in this subject, so it would be very nice, if you can help me.

Regards

Simon