Re: [PATCH 0/2] of: unittest: add overlay gpio test to catch gpio hog problem

[Frank Rowand]

On 1/28/20 11:46 PM, frowand.list@xxxxxxxxx wrote:
> From: Frank Rowand <frank.rowand@xxxxxxxx>
> 
> Geert reports that gpio hog nodes are not properly processed when
> the gpio hog node is added via an overlay reply and provides an
> RFC patch to fix the problem [1].
> 
> Add a unittest that shows the problem.  Unittest will report "1 failed"
> test before applying Geert's RFC patch and "0 failed" after applying
> Geert's RFC patch.
> 
> I did not have a development system for which it would be easy to
> experiment with applying an overlay containing a gpio hog, so I
> instead created this unittest that uses a fake gpio node.
> 
> Some tests in the devicetree unittests result in printk messages
> from the code being tested.  It can be difficult to determine
> whether the messages are the result of unittest or are potentially
> reporting bugs that should be fixed.  The most recent example of
> a person asking whether to be concerned about these messages is [2].
> 
> Patch 2 adds annotations for all messages triggered by unittests,
> except KERN_DEBUG messages.  (KERN_DEBUG is a special case due to the
> possible interaction of CONFIG_DYNAMIC_DEBUG.)
> 
> The annotations added in patch 2/2 add a small amount of verbosity
> to the console output.  I have created a proof of concept tool to
> explore (1) how test harnesses could use the annotations and
> (2) how to make the resulting console output easier to read and
> understand as a human being.  The tool 'of_unittest_expect' is
> available at https://github.com/frowand/dt_tools
> 
> The format of the annotations is expected to change when unittests
> are converted to use the kunit infrastructure when the broader
> testing community has an opportunity to discuss the implementation
> of annotations of test triggered messages.
> 
> [1] https://lore.kernel.org/linux-devicetree/20191230133852.5890-1-geert+renesas@xxxxxxxxx/
> [2] https://lore.kernel.org/r/6021ac63-b5e0-ed3d-f964-7c6ef579cd68@xxxxxxxxxx
> 
> Frank Rowand (2):
>   of: unittest: add overlay gpio test to catch gpio hog problem
>   of: unittest: annotate warnings triggered by unittest
> 
>  drivers/of/unittest-data/Makefile             |   8 +-
>  drivers/of/unittest-data/overlay_gpio_01.dts  |  23 +
>  drivers/of/unittest-data/overlay_gpio_02a.dts |  16 +
>  drivers/of/unittest-data/overlay_gpio_02b.dts |  16 +
>  drivers/of/unittest-data/overlay_gpio_03.dts  |  23 +
>  drivers/of/unittest-data/overlay_gpio_04a.dts |  16 +
>  drivers/of/unittest-data/overlay_gpio_04b.dts |  16 +
>  drivers/of/unittest.c                         | 630 ++++++++++++++++++++++++--
>  8 files changed, 717 insertions(+), 31 deletions(-)
>  create mode 100644 drivers/of/unittest-data/overlay_gpio_01.dts
>  create mode 100644 drivers/of/unittest-data/overlay_gpio_02a.dts
>  create mode 100644 drivers/of/unittest-data/overlay_gpio_02b.dts
>  create mode 100644 drivers/of/unittest-data/overlay_gpio_03.dts
>  create mode 100644 drivers/of/unittest-data/overlay_gpio_04a.dts
>  create mode 100644 drivers/of/unittest-data/overlay_gpio_04b.dts
> 

Console output after patch 2/2, filtered by 'of_unittest_expect':

   ndroid Bootloader - UART_DM Initialized!!!
   [0] welcome to lk
   
   [10] platform_init()
   [10] target_init()
   [10] Display Init: Start
   [10] display_init(),target_id=10.
   [30] Config MIPI_VIDEO_PANEL.
   [30] Turn on MIPI_VIDEO_PANEL.
   [50] Video lane tested successfully
   [50] Display Init: Done
   [80] Loading keystore failed status 5 [80] ERROR: scm_protect_keystore Failed[200] USB init ept @ 0xf96b000
   [220] fastboot_init()
   [220] udc_start()
   [340] -- reset --
   [350] -- portchange --
   [460] -- reset --
   [460] -- portchange --
   [650] fastboot: processing commands
   [770] fastboot: download:00f30800
   [1260] fastboot: boot
   [1280] Found Appeneded Flattened Device tree
   [1280] cmdline: console=ttyMSM0,115200,n8 androidboot.hardware=qcom maxcpus=2 msm_rtb.filter=0x37 ehci-hcd.park=3 norandmaps androidboot.emmc=true androidboot.serialno=40081c41 androidboot.baseband=apq
   [1300] Updating device tree: start
   [1310] Updating device tree: done
   [1310] booting linux @ 0x8000, ramdisk @ 0x2000000 (9533134), tags/device tree @ 0x1e00000
   [1320] Turn off MIPI_VIDEO_PANEL.
   [1320] Continuous splash enabled, keeping panel alive.
   Booting Linux on physical CPU 0x0
   Linux version 5.5.0-00002-g7d506dfcce24 (frowand@xps8900) (gcc version 4.6.x-google 20120106 (prerelease) (GCC)) #7 SMP PREEMPT Tue Jan 28 23:10:47 CST 2020
   CPU: ARMv7 Processor [512f06f0] revision 0 (ARMv7), cr=10c5787d
   CPU: div instructions available: patching division code
   CPU: PIPT / VIPT nonaliasing data cache, PIPT instruction cache
   OF: fdt: Machine model: Qualcomm APQ8074 Dragonboard
   Memory policy: Data cache writealloc
   cma: Reserved 256 MiB at 0x70000000
   percpu: Embedded 19 pages/cpu s48192 r8192 d21440 u77824
   Built 1 zonelists, mobility grouping on.  Total pages: 490240
   Kernel command line: console=ttyMSM0,115200,n8 androidboot.hardware=qcom maxcpus=2 msm_rtb.filter=0x37 ehci-hcd.park=3 norandmaps androidboot.emmc=true androidboot.serialno=40081c41 androidboot.baseband=apq
   Dentry cache hash table entries: 131072 (order: 7, 524288 bytes, linear)
   Inode-cache hash table entries: 65536 (order: 6, 262144 bytes, linear)
   mem auto-init: stack:off, heap alloc:off, heap free:off
   Memory: 1664560K/1967104K available (8192K kernel code, 859K rwdata, 3800K rodata, 1024K init, 268K bss, 40400K reserved, 262144K cma-reserved, 1048576K highmem)
   SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
   rcu: Preemptible hierarchical RCU implementation.
   	Tasks RCU enabled.
   rcu: RCU calculated value of scheduler-enlistment delay is 10 jiffies.
   NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16
   random: get_random_bytes called from start_kernel+0x2fc/0x508 with crng_init=0
   arch_timer: cp15 and mmio timer(s) running at 19.20MHz (virt/virt).
   clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0x46d987e47, max_idle_ns: 440795202767 ns
   sched_clock: 56 bits at 19MHz, resolution 52ns, wraps every 4398046511078ns
   Switching to timer-based delay loop, resolution 52ns
   Console: colour dummy device 80x30
   Calibrating delay loop (skipped), value calculated using timer frequency.. 38.40 BogoMIPS (lpj=192000)
   pid_max: default: 32768 minimum: 301
   Mount-cache hash table entries: 2048 (order: 1, 8192 bytes, linear)
   Mountpoint-cache hash table entries: 2048 (order: 1, 8192 bytes, linear)
   CPU: Testing write buffer coherency: ok
   CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
   Setting up static identity map for 0x300000 - 0x300060
   rcu: Hierarchical SRCU implementation.
   smp: Bringing up secondary CPUs ...
   CPU1: thread -1, cpu 1, socket 0, mpidr 80000001
   smp: Brought up 1 node, 2 CPUs
   SMP: Total of 2 processors activated (76.80 BogoMIPS).
   CPU: All CPU(s) started in SVC mode.
   devtmpfs: initialized
   VFP support v0.3: implementor 51 architecture 64 part 6f variant 2 rev 0
   clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
   futex hash table entries: 1024 (order: 4, 65536 bytes, linear)
   pinctrl core: initialized pinctrl subsystem
   thermal_sys: Registered thermal governor 'step_wise'
   NET: Registered protocol family 16
   DMA: preallocated 256 KiB pool for atomic coherent allocations
   cpuidle: using governor menu
   hw-breakpoint: found 5 (+1 reserved) breakpoint and 4 watchpoint registers.
   hw-breakpoint: maximum watchpoint size is 8 bytes.
   iommu: Default domain type: Translated 
   vgaarb: loaded
   SCSI subsystem initialized
   usbcore: registered new interface driver usbfs
   usbcore: registered new interface driver hub
   usbcore: registered new device driver usb
   Advanced Linux Sound Architecture Driver Initialized.
   clocksource: Switched to clocksource arch_sys_counter
   NET: Registered protocol family 2
   tcp_listen_portaddr_hash hash table entries: 512 (order: 0, 6144 bytes, linear)
   TCP established hash table entries: 8192 (order: 3, 32768 bytes, linear)
   TCP bind hash table entries: 8192 (order: 4, 65536 bytes, linear)
   TCP: Hash tables configured (established 8192 bind 8192)
   UDP hash table entries: 512 (order: 2, 16384 bytes, linear)
   UDP-Lite hash table entries: 512 (order: 2, 16384 bytes, linear)
   NET: Registered protocol family 1
   RPC: Registered named UNIX socket transport module.
   RPC: Registered udp transport module.
   RPC: Registered tcp transport module.
   RPC: Registered tcp NFSv4.1 backchannel transport module.
   PCI: CLS 0 bytes, default 64
   Trying to unpack rootfs image as initramfs...
   Freeing initrd memory: 9312K
   hw perfevents: enabled with armv7_krait PMU driver, 5 counters available
   Initialise system trusted keyrings
   workingset: timestamp_bits=30 max_order=19 bucket_order=0
   NFS: Registering the id_resolver key type
   Key type id_resolver registered
   Key type id_legacy registered
   Key type cifs.idmap registered
   jffs2: version 2.2. (NAND) Â 2001-2006 Red Hat, Inc.
   fuse: init (API version 7.31)
   Key type asymmetric registered
   Asymmetric key parser 'x509' registered
   bounce: pool size: 64 pages
   Block layer SCSI generic (bsg) driver version 0.4 loaded (major 250)
   io scheduler mq-deadline registered
   io scheduler kyber registered
   msm_serial f991e000.serial: msm_serial: detected port #0
   msm_serial f991e000.serial: uartclk = 7372800
   f991e000.serial: ttyMSM0 at MMIO 0xf991e000 (irq = 28, base_baud = 460800) is a MSM
   msm_serial: console setup on port #0
   printk: console [ttyMSM0] enabled
   msm_serial: driver initialized
   brd: module loaded
   loop: module loaded
   SCSI Media Changer driver v0.25 
   spmi spmi-0: PMIC arbiter version v1 (0x20000002)
   s1: supplied by regulator-dummy
   s2: supplied by regulator-dummy
   s3: supplied by regulator-dummy
   s4: Bringing 5100000uV into 5000000-5000000uV
   l1: supplied by regulator-dummy
   l2: supplied by regulator-dummy
   l3: supplied by regulator-dummy
   l4: supplied by regulator-dummy
   l5: supplied by regulator-dummy
   l6: supplied by regulator-dummy
   l7: supplied by regulator-dummy
   l8: supplied by regulator-dummy
   l9: supplied by regulator-dummy
   l10: supplied by regulator-dummy
   l11: supplied by regulator-dummy
   l12: supplied by regulator-dummy
   l13: supplied by regulator-dummy
   l14: supplied by regulator-dummy
   l15: supplied by regulator-dummy
   l16: supplied by regulator-dummy
   l17: supplied by regulator-dummy
   l18: supplied by regulator-dummy
   l19: supplied by regulator-dummy
   l20: supplied by regulator-dummy
   l21: supplied by regulator-dummy
   l22: supplied by regulator-dummy
   l23: supplied by regulator-dummy
   l24: supplied by regulator-dummy
   lvs1: supplied by regulator-dummy
   lvs2: supplied by regulator-dummy
   lvs3: supplied by regulator-dummy
   5vs1: supplied by s4
   5vs2: supplied by s4
   libphy: Fixed MDIO Bus: probed
   SLIP: version 0.8.4-NET3.019-NEWTTY (dynamic channels, max=256) (6 bit encapsulation enabled).
   CSLIP: code copyright 1989 Regents of the University of California.
   usbcore: registered new interface driver ax88179_178a
   usbcore: registered new interface driver cdc_ether
   usbcore: registered new interface driver net1080
   usbcore: registered new interface driver cdc_subset
   usbcore: registered new interface driver cdc_ncm
   ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
   ehci-pci: EHCI PCI platform driver
   usbcore: registered new interface driver cdc_acm
   cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters
   rtc-pm8xxx fc4cf000.spmi:pm8941@0:rtc@6000: registered as rtc0
   i2c /dev entries driver
   qcom-smbb fc4cf000.spmi:pm8941@0:charger@1000: Initializing SMBB rev 3
   otg-vbus: supplied by 5vs1
   cpuidle: enable-method property 'qcom,kpss-acc-v2' found operations
   cpuidle: enable-method property 'qcom,kpss-acc-v2' found operations
   cpuidle: enable-method property 'qcom,kpss-acc-v2' found operations
   cpuidle: enable-method property 'qcom,kpss-acc-v2' found operations
   sdhci: Secure Digital Host Controller Interface driver
   sdhci: Copyright(c) Pierre Ossman
   sdhci-pltfm: SDHCI platform and OF driver helper
   sdhci_msm f98a4900.sdhci: Got CD GPIO
   usbcore: registered new interface driver usbhid
   usbhid: USB HID core driver
   oprofile: using timer interrupt.
   NET: Registered protocol family 17
   Key type dns_resolver registered
   Registering SWP/SWPB emulation handler
   Loading compiled-in X.509 certificates
   debugfs: Directory 'fc4a9000.thermal-sensor' with parent 'tsens' already present!
   sdhci_msm f98a4900.sdhci: Got CD GPIO
   sdhci_msm f98a4900.sdhci: Got CD GPIO
   s1: supplied by regulator-dummy
   s1: Bringing 0uV into 675000-675000uV
   sdhci_msm f98a4900.sdhci: Got CD GPIO
   s2: supplied by regulator-dummy
   rtc-pm8xxx fc4cf000.spmi:pm8941@0:rtc@6000: setting system clock to 1970-01-17T00:05:31 UTC (1382731)
-> ### dt-test ### start of unittest - you will see error messages
   s2: Bringing 0uV into 500000-500000uV
ok Duplicate name in testcase-data, renamed to "duplicate-name#1"
   s3: supplied by regulator-dummy
   s3: Bringing 0uV into 500000-500000uV
ok OF: /testcase-data/phandle-tests/consumer-a: could not get #phandle-cells-missing for /testcase-data/phandle-tests/provider1
   s4: supplied by regulator-dummy
   s4: Bringing 0uV into 500000-500000uV
ok OF: /testcase-data/phandle-tests/consumer-a: could not get #phandle-cells-missing for /testcase-data/phandle-tests/provider1
   s5: supplied by regulator-dummy
   s6: supplied by regulator-dummy
ok OF: /testcase-data/phandle-tests/consumer-a: could not find phandle
   s7: supplied by regulator-dummy
ok OF: /testcase-data/phandle-tests/consumer-a: could not find phandle
   s8: supplied by regulator-dummy
   s1: supplied by regulator-dummy
ok OF: /testcase-data/phandle-tests/consumer-a: #phandle-cells = 3 found -1
   s1: Bringing 0uV into 1300000-1300000uV
   s2: supplied by regulator-dummy
ok OF: /testcase-data/phandle-tests/consumer-a: #phandle-cells = 3 found -1
   sdhci_msm f98a4900.sdhci: Got CD GPIO
   s2: Bringing 0uV into 2150000-2150000uV
ok OF: /testcase-data/phandle-tests/consumer-b: could not get #phandle-missing-cells for /testcase-data/phandle-tests/provider1
   s3: supplied by regulator-dummy
   s3: Bringing 0uV into 1800000-1800000uV
ok OF: /testcase-data/phandle-tests/consumer-b: could not find phandle
   l1: supplied by s1
ok OF: /testcase-data/phandle-tests/consumer-b: #phandle-cells = 2 found -1
   l1: Bringing 0uV into 1225000-1225000uV
   l2: supplied by s3
ok platform testcase-data:testcase-device2: IRQ index 0 not found
   l2: Bringing 0uV into 1200000-1200000uV
   l3: supplied by s1
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data/overlay-node/test-bus/test-unittest0/status
   l3: Bringing 0uV into 1225000-1225000uV
   l4: supplied by s1
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data/overlay-node/test-bus/test-unittest1/status
   l4: Bringing 0uV into 1225000-1225000uV
   l5: supplied by s2
   sdhci_msm f98a4900.sdhci: Got CD GPIO
   l5: Bringing 0uV into 1800000-1800000uV
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data/overlay-node/test-bus/test-unittest2/status
   l6: supplied by s2
   l6: Bringing 0uV into 1800000-1800000uV
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data/overlay-node/test-bus/test-unittest3/status
   l7: supplied by s2
   l7: Bringing 0uV into 1800000-1800000uV
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data/overlay-node/test-bus/test-unittest5/status
   sdhci_msm f98a4900.sdhci: Got CD GPIO
   l8: supplied by regulator-dummy
   l8: Bringing 0uV into 1800000-1800000uV
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data/overlay-node/test-bus/test-unittest6/status
   l9: supplied by regulator-dummy
   l9: Bringing 0uV into 1800000-1800000uV
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data/overlay-node/test-bus/test-unittest7/status
   sdhci_msm f98a4900.sdhci: Got CD GPIO
   l10: supplied by regulator-dummy
   l10: Bringing 0uV into 1800000-1800000uV
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data/overlay-node/test-bus/test-unittest8/status
   l11: supplied by s1
   l11: Bringing 0uV into 1300000-1300000uV
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data/overlay-node/test-bus/test-unittest8/property-foo
   sdhci_msm f98a4900.sdhci: Got CD GPIO
   l12: supplied by s2
ok OF: overlay: node_overlaps_later_cs: #6 overlaps with #7 @/testcase-data/overlay-node/test-bus/test-unittest8
   l12: Bringing 0uV into 1800000-1800000uV
ok OF: overlay: overlay #6 is not topmost
   l13: supplied by regulator-dummy
ok i2c i2c-1: Added multiplexed i2c bus 2
   l13: Bringing 0uV into 1800000-1800000uV
   l14: supplied by s2
   sdhci_msm f98a4900.sdhci: Got CD GPIO
   l14: Bringing 0uV into 1800000-1800000uV
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data/overlay-node/test-bus/i2c-test-bus/test-unittest12/status
   l15: supplied by s2
   l15: Bringing 0uV into 2050000-2050000uV
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data/overlay-node/test-bus/i2c-test-bus/test-unittest13/status
   sdhci_msm f98a4900.sdhci: Got CD GPIO
   l16: supplied by regulator-dummy
   l16: Bringing 0uV into 2700000-2700000uV
ok i2c i2c-1: Added multiplexed i2c bus 3
   l17: supplied by regulator-dummy
   l17: Bringing 0uV into 2700000-2700000uV
   sdhci_msm f98a4900.sdhci: Got CD GPIO
   l18: supplied by regulator-dummy
   l18: Bringing 0uV into 2850000-2850000uV
   l19: supplied by regulator-dummy
ok GPIO line 315 (line-B-input) hogged as input
   l19: Bringing 0uV into 3300000-3300000uV
ok GPIO line 309 (line-A-input) hogged as input
   l20: supplied by regulator-dummy
   l20: Bringing 0uV into 2950000-2950000uV
   sdhci_msm f98a4900.sdhci: Got CD GPIO
   l21: supplied by regulator-dummy
   l21: Bringing 0uV into 2950000-2950000uV
   l22: supplied by regulator-dummy
ok GPIO line 307 (line-D-input) hogged as input
   l22: Bringing 0uV into 3000000-3000000uV
   l23: supplied by regulator-dummy
   l23: Bringing 0uV into 3000000-3000000uV
** of_unittest_expect WARNING - not found ---> GPIO line <<int>> (line-C-input) hogged as input
   l24: supplied by regulator-dummy
>> ### dt-test ### FAIL of_unittest_overlay_gpio():2666 unittest_gpio_chip_request() called 0 times (expected 1 time)
   l24: Bringing 0uV into 3075000-3075000uV
   lvs1: supplied by s3
   lvs2: supplied by s3
   mmc0: SDHCI controller on f98a4900.sdhci [f98a4900.sdhci] using ADMA
   lvs3: supplied by s3
   5vs1: supplied by s4
   5vs2: supplied by s4
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data-2/substation@100/status
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data-2/fairway-1/status
   mmc1: SDHCI controller on f9824900.sdhci [f9824900.sdhci] using ADMA
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data-2/fairway-1/ride@100/track@30/incline-up
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data-2/fairway-1/ride@100/track@40/incline-up
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data-2/lights@40000/status
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data-2/lights@40000/color
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data-2/lights@40000/rate
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /__symbols__/hvac_2
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /__symbols__/ride_200
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /__symbols__/ride_200_left
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /__symbols__/ride_200_right
   mmc0: new ultra high speed DDR50 SDHC card at address aaaa
   mmcblk0: mmc0:aaaa SU16G 14.8 GiB 
ok OF: overlay: ERROR: multiple fragments add and/or delete node /testcase-data-2/substation@100/motor-1/controller
    mmcblk0: p1
ok OF: overlay: ERROR: multiple fragments add, update, and/or delete property /testcase-data-2/substation@100/motor-1/controller/name
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data-2/substation@100/motor-1/rpm_avail
ok OF: overlay: WARNING: memory leak will occur if overlay removed, property: /testcase-data-2/substation@100/motor-1/rpm_avail
ok OF: overlay: ERROR: multiple fragments add, update, and/or delete property /testcase-data-2/substation@100/motor-1/rpm_avail
-> ### dt-test ### end of unittest - 258 passed, 1 failed
   ALSA device[    4.328014] mmc1: new HS200 MMC card at address 0001
   Freeing unused kernel memory: 1024K
   Run /init as init process
   mmcblk1: mmc1:0001 SEM16G 14.7 GiB 
   mmcblk1boot0: mmc1:0001 SEM16G partition 1 4.00 MiB
   mmcblk1boot1: mmc1:0001 SEM16G partition 2 4.00 MiB
   mmcblk1rpmb: mmc1:0001 SEM16G partition 3 4.00 MiB, chardev (247:0)
    mmcblk1: p1 p2 p3 p4 p5 p6 p7 p8 p9 p10 p11 p12 p13 p14 p15 p16 p17 p18 p19 p20
   mkdir: can't create directory '/bin': File exists
   mkdir: can't create directory '/dev': File exists
   /init: line 25: can't create /proc/sys/kernel/hotplug: nonexistent directory
   mdev: unknown user/group 'root:uucp' on line 34
   Attempt to mount partitions: /usr/system /usr/data
   Mounting partitions from: /dev/mmcblk1
   EXT4-fs (mmcblk1p12): mounted filesystem with ordered data mode. Opts: (null)
   random: fast init done
   EXT4-fs (mmcblk1p13): recovery complete
   EXT4-fs (mmcblk1p13): mounted filesystem with ordered data mode. Opts: (null)
   / # 
   / # cat /proc/version
   Linux version 5.5.0-00002-g7d506dfcce24 (frowand@xps8900) (gcc version 4.6.x-google 20120106 (prerelease) (GCC)) #7 SMP PREEMPT Tue Jan 28 23:10:47 CST 2020