[RFC] PCI: pci-imx6: Add delay to workaround kernel hang
Fabio Estevam
festevam at gmail.com
Wed Jun 25 20:43:19 PDT 2014
On Thu, Jun 26, 2014 at 12:12 AM, Shawn Guo <shawn.guo at freescale.com> wrote:
> On Tue, Jun 24, 2014 at 04:18:27PM -0300, Fabio Estevam wrote:
>> From: Fabio Estevam <fabio.estevam at freescale.com>
>>
>> When the mx6 PCI conctroller is initialized in the bootloader we see a kernel
>> hang inside imx6_add_pcie_port().
>>
>> Adding a 30ms delay allows the kernel to boot.
>
> We may not want to add a random delay into the driver before we
> understand the root cause of the issue.
Yes, that's why I sent this as RFC and also explained it below the ---
line that I am actually trying to get some help with this issue.
>
> Do you see this issue with FSL kernel?
Yes, it also hangs.
It is reproducible in 100% of the boots. Just need to use mainline
U-boot (which has PCI driver enabled by default).
I am using an Intel Wifi 7260 PCI card. This was also reported by
other folks in the U-boot list.
Below is the log with linux-next kernel and earlyprintk enabled:
U-Boot 2014.07-rc1-15766-g5f46552 (Jun 24 2014 - 17:41:55)
CPU: Freescale i.MX6Q rev1.2 at 792 MHz
Reset cause: POR
Board: MX6-SabreSD
I2C: ready
DRAM: 1 GiB
MMC: FSL_SDHC: 0, FSL_SDHC: 1, FSL_SDHC: 2
00:01.0 - 16c3:abcd - Bridge device
01:00.0 - 8086:08b1 - Network controller
No panel detected: default to Hannstar-XGA
Display: Hannstar-XGA (1024x768)
In: serial
Out: serial
Err: serial
PMIC: PFUZE100 ID=0x10
Net: FEC [PRIME]
Hit any key to stop autoboot: 0
Booting from net ...
FEC Waiting for PHY auto negotiation to complete.. done
Using FEC device
TFTP from server 192.168.0.2; our IP address is 192.168.0.8
Filename 'zImage'.
Load address: 0x12000000
Loading: #################################################################
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#############################################################
1.7 MiB/s
done
Bytes transferred = 5302272 (50e800 hex)
Using FEC device
TFTP from server 192.168.0.2; our IP address is 192.168.0.8
Filename 'imx6q-sabresd.dtb'.
Load address: 0x18000000
Loading: #######
1.5 MiB/s
done
Bytes transferred = 33744 (83d0 hex)
Kernel image @ 0x12000000 [ 0x000000 - 0x50e800 ]
## Flattened Device Tree blob at 18000000
Booting using the fdt blob at 0x18000000
Using Device Tree in place at 18000000, end 1800b3cf
Starting kernel ...
Uncompressing Linux... done, booting the kernel.
Booting Linux on physical CPU 0x0
Linux version 3.16.0-rc2-next-20140625 (fabio at fabio-Latitude-E6410)
(gcc version 4.7.3 (Ubuntu/Linaro 4.7.3-1ubuntu1) ) #1440 SMP Thu
Jun 26 00:38:33 BRT 2014
CPU: ARMv7 Processor [412fc09a] revision 10 (ARMv7), cr=10c5387d
CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
Machine model: Freescale i.MX6 Quad SABRE Smart Device Board
bootconsole [earlycon0] enabled
cma: Reserved 16 MiB at 4f000000
Memory policy: Data cache writealloc
PERCPU: Embedded 8 pages/cpu @be7a6000 s8896 r8192 d15680 u32768
Built 1 zonelists in Zone order, mobility grouping on. Total pages: 260096
Kernel command line: console=ttymxc0,115200 root=/dev/nfs ip=dhcp
nfsroot=192.168.0.2:/tftpboot/rfs,v3,tcp earlyprintk
PID hash table entries: 4096 (order: 2, 16384 bytes)
Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
Memory: 1004880K/1048576K available (6579K kernel code, 406K rwdata,
2264K rodata, 340K init, 8331K bss, 43696K reserved, 0K highmem)
Virtual kernel memory layout:
vector : 0xffff0000 - 0xffff1000 ( 4 kB)
fixmap : 0xffc00000 - 0xffe00000 (2048 kB)
vmalloc : 0xc0800000 - 0xff000000 (1000 MB)
lowmem : 0x80000000 - 0xc0000000 (1024 MB)
pkmap : 0x7fe00000 - 0x80000000 ( 2 MB)
modules : 0x7f000000 - 0x7fe00000 ( 14 MB)
.text : 0x80008000 - 0x808aafbc (8844 kB)
.init : 0x808ab000 - 0x809002c0 ( 341 kB)
.data : 0x80902000 - 0x80967a40 ( 407 kB)
.bss : 0x80967a48 - 0x8118aa10 (8332 kB)
SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
Hierarchical RCU implementation.
NR_IRQS:16 nr_irqs:16 16
L2C-310 erratum 769419 enabled
L2C-310 enabling early BRESP for Cortex-A9
L2C-310 full line of zeros enabled for Cortex-A9
L2C-310 ID prefetch enabled, offset 1 lines
L2C-310 dynamic clock gating enabled, standby mode enabled
L2C-310 cache controller enabled, 16 ways, 1024 kB
L2C-310: CACHE_ID 0x410000c7, AUX_CTRL 0x76070001
Switching to timer-based delay loop, resolution 15ns
sched_clock: 32 bits at 66MHz, resolution 15ns, wraps every 65075262448ns
Console: colour dummy device 80x30
Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar
... MAX_LOCKDEP_SUBCLASSES: 8
... MAX_LOCK_DEPTH: 48
... MAX_LOCKDEP_KEYS: 8191
... CLASSHASH_SIZE: 4096
... MAX_LOCKDEP_ENTRIES: 32768
... MAX_LOCKDEP_CHAINS: 65536
... CHAINHASH_SIZE: 32768
memory used by lock dependency info: 5167 kB
per task-struct memory footprint: 1152 bytes
Calibrating delay loop (skipped), value calculated using timer
frequency.. 132.00 BogoMIPS (lpj=660000)
pid_max: default: 32768 minimum: 301
Mount-cache hash table entries: 2048 (order: 1, 8192 bytes)
Mountpoint-cache hash table entries: 2048 (order: 1, 8192 bytes)
CPU: Testing write buffer coherency: ok
CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
Setting up static identity map for 0x10672328 - 0x10672398
CPU1: Booted secondary processor
CPU1: thread -1, cpu 1, socket 0, mpidr 80000001
CPU2: Booted secondary processor
CPU2: thread -1, cpu 2, socket 0, mpidr 80000002
CPU3: Booted secondary processor
CPU3: thread -1, cpu 3, socket 0, mpidr 80000003
Brought up 4 CPUs
SMP: Total of 4 processors activated.
CPU: All CPU(s) started in SVC mode.
devtmpfs: initialized
VFP support v0.3: implementor 41 architecture 3 part 30 variant 9 rev 4
pinctrl core: initialized pinctrl subsystem
regulator-dummy: no parameters
NET: Registered protocol family 16
DMA: preallocated 256 KiB pool for atomic coherent allocations
CPU identified as i.MX6Q, silicon rev 1.2
vdd1p1: 800 <--> 1375 mV at 1100 mV
vdd3p0: 2800 <--> 3150 mV at 3000 mV
vdd2p5: 2000 <--> 2750 mV at 2400 mV
vddarm: 725 <--> 1450 mV at 1100 mV
vddpu: 725 <--> 1450 mV at 1100 mV
vddsoc: 725 <--> 1450 mV at 1175 mV
hw-breakpoint: found 5 (+1 reserved) breakpoint and 1 watchpoint registers.
hw-breakpoint: maximum watchpoint size is 4 bytes.
imx6q-pinctrl 20e0000.iomuxc: initialized IMX pinctrl driver
mxs-dma 110000.dma-apbh: initialized
usb_otg_vbus: 5000 mV
usb_h1_vbus: 5000 mV
wm8962-supply: no parameters
vgaarb: loaded
SCSI subsystem initialized
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
i2c i2c-0: IMX I2C adapter registered
i2c i2c-1: IMX I2C adapter registered
i2c i2c-2: IMX I2C adapter registered
Linux video capture interface: v2.00
pps_core: LinuxPPS API ver. 1 registered
pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti
<giometti at linux.it>
PTP clock support registered
Advanced Linux Sound Architecture Driver Initialized.
cfg80211: Calling CRDA to update world regulatory domain
Switched to clocksource mxc_timer1
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