iMX6SX RMII kernel freeze issue

[texnikk]

Hello,

We've been trying to connect FEC1 of iMX6SX with DP83640 in RMII mode.

We're using external 50MHz generator to supply both FEC and PHY with REF_CLK.

Following changes to clk-imx6sx.c:

+imx_clk_set_rate(clks[IMX6SX_CLK_ENET_REF], 50000000);

IOMUXC_GPR_GPR1 bits are:

ENET1_CLK_SEL = "1", 

ENET1_TX_CLK_DIR = "0"

SION bit is set:

#define MX6SX_PAD_ENET1_TX_CLK__ENET1_REF_CLK1 0x0090 0x03D8 0x0760 0x11 0x1

Device tree:

&fec1 {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_enet1_rmii>;
	phy-supply = <&reg_enet_3v3>;
	phy-mode = "rmii";
	phy-handle = <&ethphy1>;
	phy-reset-gpios = <&gpio2 1 GPIO_ACTIVE_LOW>;
	status = "okay";

	mdio {
		#address-cells = <1>;
		#size-cells = <0>;

		ethphy1: ethernet-phy@1 {
			reg = <1>;
			max-speed = <100>;
			interrupt-parent = <&gpio2>;
			interrupts = <0 IRQ_TYPE_LEVEL_LOW>;
		};
	};
};

&iomuxc {
	imx6sx {
		pinctrl_enet1_rmii: enet1rmiigrp {
			fsl,pins =
				<MX6SX_PAD_ENET1_CRS__GPIO2_IO_1	0xa0b1>, //RST
				<MX6SX_PAD_ENET1_MDC__ENET1_MDC		0xa088>,
				<MX6SX_PAD_ENET1_MDIO__ENET1_MDIO	0xa088>,
				<MX6SX_PAD_RGMII1_TD0__ENET1_TX_DATA_0	0xa088>,
				<MX6SX_PAD_RGMII1_TD1__ENET1_TX_DATA_1	0xa088>,
				<MX6SX_PAD_RGMII1_TX_CTL__ENET1_TX_EN	0xa088>,
				//<MX6SX_PAD_ENET1_TX_CLK__ENET1_REF_CLK1	0x10f9>,

				<MX6SX_PAD_ENET1_TX_CLK__ENET1_REF_CLK1 0x30C1>,
				<MX6SX_PAD_ENET1_COL__GPIO2_IO_0		0x3081>, // INT
				<MX6SX_PAD_RGMII1_RD0__ENET1_RX_DATA_0	0x3081>,
				<MX6SX_PAD_RGMII1_RD1__ENET1_RX_DATA_1	0x3081>,
				<MX6SX_PAD_RGMII1_RX_CTL__ENET1_RX_EN	0x3081>; // ->CRS/CRS_DV
		};
	};
};

The problem is that when kernel is starting, it hangs on following lines:

[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] Linux version 4.9.11-VenOS (root@f8558289a7eb) (gcc version 7.4.1 20181213 [linaro-7.4-2019.02 revision 56ec6f6b99cc167ff0c2f8e1a2eed33b1ed
c85d4] (Linaro GCC 7.4-2019.02) ) #1 SMP PREEMPT Fri Sep 10 09:19:07 UTC 2021
[    0.000000] CPU: ARMv7 Processor [412fc09a] revision 10 (ARMv7), cr=10c53c7d
[    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[    0.000000] OF: fdt:Machine model: DC500
[    0.000000] Reserved memory: created CMA memory pool at 0x98000000, size 64 MiB
[    0.000000] OF: reserved mem: initialized node linux,cma, compatible id shared-dma-pool
[    0.000000] Memory policy: Data cache writealloc
[    0.000000] percpu: Embedded 13 pages/cpu @9fbaf000 s21580 r8192 d23476 u53248
[    0.000000] Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 130048
[    0.000000] Kernel command line: mtdparts=gpmi-nand:2m(boot),1m(env),509m(data) video=fb_lcd panic=1 console=ttymxc0,115200 ubi.mtd=2 root=ubi0:boot1 r
o noatime rootfstype=ubifs init=/launcher
[    0.000000] PID hash table entries: 2048 (order: 1, 8192 bytes)
[    0.000000] Dentry cache hash table entries: 65536 (order: 6, 262144 bytes)
[    0.000000] Inode-cache hash table entries: 32768 (order: 5, 131072 bytes)
[    0.000000] Memory: 445104K/524288K available (5120K kernel code, 189K rwdata, 1624K rodata, 1024K init, 392K bss, 13648K reserved, 65536K cma-reserved
, 0K highmem)
[    0.000000] Virtual kernel memory layout:
[    0.000000]     vector  : 0xffff0000 - 0xffff1000   (   4 kB)
[    0.000000]     fixmap  : 0xffc00000 - 0xfff00000   (3072 kB)
[    0.000000]     vmalloc : 0xa0800000 - 0xff800000   (1520 MB)
[    0.000000]     lowmem  : 0x80000000 - 0xa0000000   ( 512 MB)
[    0.000000]     pkmap   : 0x7fe00000 - 0x80000000   (   2 MB)
[    0.000000]     modules : 0x7f000000 - 0x7fe00000   (  14 MB)
[    0.000000]       .text : 0x80008000 - 0x80600000   (6112 kB)
[    0.000000]       .init : 0x80800000 - 0x80900000   (1024 kB)
[    0.000000]       .data : 0x80900000 - 0x8092f6c0   ( 190 kB)
[    0.000000]        .bss : 0x80931000 - 0x809932b4   ( 393 kB)
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[    0.000000] Preemptible hierarchical RCU implementation.
[    0.000000]  Build-time adjustment of leaf fanout to 32.
[    0.000000]  RCU restricting CPUs from NR_CPUS=4 to nr_cpu_ids=1.
[    0.000000] RCU: Adjusting geometry for rcu_fanout_leaf=32, nr_cpu_ids=1
[    0.000000] NR_IRQS:16 nr_irqs:16 16
[    0.000000] L2C-310 erratum 769419 enabled
[    0.000000] L2C-310 enabling early BRESP for Cortex-A9
[    0.000000] L2C-310 full line of zeros enabled for Cortex-A9
[    0.000000] L2C-310 ID prefetch enabled, offset 16 lines
[    0.000000] L2C-310 dynamic clock gating enabled, standby mode enabled
[    0.000000] L2C-310 cache controller enabled, 16 ways, 256 kB
[    0.000000] L2C-310: CACHE_ID 0x410000c8, AUX_CTRL 0x76430001
[    0.000000] Switching to timer-based delay loop, resolution 333ns
[    0.000007] sched_clock: 32 bits at 3000kHz, resolution 333ns, wraps every 715827882841ns
[    0.000025] clocksource: mxc_timer1: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 637086815595 ns
[    0.001670] Console: colour dummy device 80x30
[    0.001691] Calibrating delay loop (skipped), value calculated using timer frequency.. 6.00 BogoMIPS (lpj=30000)
[    0.001706] pid_max: default: 32768 minimum: 301
[    0.001803] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
[    0.001814] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
[    0.002444] CPU: Testing write buffer coherency: ok
[    0.002740] CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
[    0.002784] Setting up static identity map for 0x80100000 - 0x80100058
[    0.100359] Brought up 1 CPUs
[    0.100376] SMP: Total of 1 processors activated (6.00 BogoMIPS).
[    0.100384] CPU: All CPU(s) started in SVC mode.
[    0.101177] devtmpfs: initialized
[    0.109899] VFP support v0.3: implementor 41 architecture 3 part 30 variant 9 rev 4
[    0.110243] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[    0.113940] pinctrl core: initialized pinctrl subsystem
[    0.114946] NET: Registered protocol family 16
[    0.121762] DMA: preallocated 256 KiB pool for atomic coherent allocations
[    0.150617] cpuidle: using governor menu
[    0.171441] setting gpr mode 1
[    0.171764] hw-breakpoint: found 5 (+1 reserved) breakpoint and 1 watchpoint registers.
[    0.171776] hw-breakpoint: maximum watchpoint size is 4 bytes.
[    0.172367] imx6sx-pinctrl 20e0000.iomuxc: initialized IMX pinctrl driver
[    0.173493] imx-gpc 20dc000.gpc: Registered imx-gpc
[    0.174209] MU is ready for cross core communication!
[    0.254907] mxs-dma 1804000.dma-apbh: initialized
[    0.258177] i2c i2c-1: IMX I2C adapter registered
[    0.258200] i2c i2c-1: can't use DMA, using PIO instead.
[    0.258846] i2c i2c-2: IMX I2C adapter registered
[    0.258867] i2c i2c-2: can't use DMA, using PIO instead.
[    0.259059] pps_core: LinuxPPS API ver. 1 registered
[    0.259069] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <giometti@linux.it>
[    0.259094] PTP clock support registered
[    0.260302] imx rpmsg driver is registered.
[    0.271332] clocksource: Switched to clocksource mxc_timer1
[    0.281578] NET: Registered protocol family 2
[    0.282175] TCP established hash table entries: 4096 (order: 2, 16384 bytes)
[    0.282226] TCP bind hash table entries: 4096 (order: 3, 32768 bytes)
[    0.282296] TCP: Hash tables configured (established 4096 bind 4096)
[    0.282364] UDP hash table entries: 256 (order: 1, 8192 bytes)
[    0.282393] UDP-Lite hash table entries: 256 (order: 1, 8192 bytes)
[    0.282567] NET: Registered protocol family 1
[    0.283178] hw perfevents: enabled with armv7_cortex_a9 PMU driver, 7 counters available
[    0.284796] Bus freq driver module loaded
[    0.285542] futex hash table entries: 256 (order: 2, 16384 bytes)
[    0.296458] workingset: timestamp_bits=30 max_order=17 bucket_order=0
[    0.302225] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[    0.309516] io scheduler noop registered
[    0.309532] io scheduler deadline registered
[    0.309743] io scheduler cfq registered (default)
[    0.432877] mxsfb 2220000.lcdif: failed to find mxc display driver 
[    0.434932] mxsfb 2220000.lcdif: Unable to allocate overlay fb memory
[    0.434947] mxsfb 2220000.lcdif: failed to map video mem for overlay
[    0.435139] mxsfb 2220000.lcdif: initialized
[    0.436442] imx-sdma 20ec000.sdma: no iram assigned, using external mem
[    0.439460] imx-sdma 20ec000.sdma: loaded firmware 3.3
[    0.445638] 2020000.serial: ttymxc0 at MMIO 0x2020000 (irq = 23, base_baud = 5000000) is a IMX
[    1.052160] console [ttymxc0] enabled
[    1.056663] 21e8000.serial: ttymxc1 at MMIO 0x21e8000 (irq = 63, base_baud = 5000000) is a IMX
[    1.066038] 21ec000.serial: ttymxc2 at MMIO 0x21ec000 (irq = 64, base_baud = 5000000) is a IMX
[    1.075382] 21f0000.serial: ttymxc3 at MMIO 0x21f0000 (irq = 65, base_baud = 5000000) is a IMX
[    1.084751] 21f4000.serial: ttymxc4 at MMIO 0x21f4000 (irq = 66, base_baud = 5000000) is a IMX
[    1.094131] 22a0000.serial: ttymxc5 at MMIO 0x22a0000 (irq = 71, base_baud = 5000000) is a IMX
[    1.103772] imx sema4 driver is registered.
[    1.108021] [drm] Initialized
[    1.111565] [drm] Initialized vivante 1.0.0 20120216 on minor 0
[    1.128664] loop: module loaded
[    1.136940] random: fast init done
[    1.142607] nand: device found, Manufacturer ID: 0xc2, Chip ID: 0xdc
[    1.148968] nand: Macronix MX30LF4G28AC
[    1.152842] nand: 512 MiB, SLC, erase size: 128 KiB, page size: 2048, OOB size: 112
[    1.160851] gpmi-nand 1806000.gpmi-nand: mode:5 ,failed in set feature.
[    1.168424] Bad block table not found for chip 0
[    1.173915] Bad block table not found for chip 0
[    1.178538] Scanning device for bad blocks
[    1.472686] Bad eraseblock 2989 at 0x0000175a0000
[    1.556505] Bad eraseblock 3810 at 0x00001dc40000
[    1.590755] Bad block table written to 0x00001ffe0000, version 0x01
[    1.598516] Bad block table written to 0x00001ffc0000, version 0x01
[    1.604846] 3 cmdlinepart partitions found on MTD device gpmi-nand
[    1.611033] Creating 3 MTD partitions on "gpmi-nand":
[    1.616119] 0x000000000000-0x000000200000 : "boot"
[    1.632274] 0x000000200000-0x000000300000 : "env"
[    1.648275] 0x000000300000-0x000020000000 : "data"
[    1.670072] gpmi-nand 1806000.gpmi-nand: driver registered.
[    1.677618] libphy: Fixed MDIO Bus: probed
[    1.685330] pps pps0: new PPS source ptp0
[    1.694736] libphy: fec_enet_mii_bus: probed
[    1.710467] fec 2188000.ethernet eth0: registered PHC device 0
[    1.717585] input: 20cc000.snvs:snvs-powerkey as /devices/soc0/soc/2000000.aips-bus/20cc000.snvs/20cc000.snvs:snvs-powerkey/input/input0
[    1.730829] input: fts_ts as /devices/soc0/soc/2100000.aips-bus/21a4000.i2c/i2c-1/1-0038/input/input1
[    1.994095] rtc-pcf85063 2-0051: rtc core: registered rtc-pcf85063 as rtc0
[    2.001709] snvs_rtc 20cc000.snvs:snvs-rtc-lp: rtc core: registered 20cc000.snvs:snvs-r as rtc1
[    2.010570] i2c /dev entries driver
[    2.016033] imx2-wdt 20bc000.wdog: timeout 60 sec (nowayout=0)
[    2.022927] sdhci: Secure Digital Host Controller Interface driver
[    2.029118] sdhci: Copyright(c) Pierre Ossman
[    2.033537] sdhci-pltfm: SDHCI platform and OF driver helper
[    2.040259] sdhci-esdhc-imx 2198000.usdhc: allocated mmc-pwrseq
[    2.111397] mmc2: SDHCI controller on 2198000.usdhc [2198000.usdhc] using ADMA
[    2.142322] mmc2: queuing unknown CIS tuple 0x80 (2 bytes)
[    2.149538] mmc2: queuing unknown CIS tuple 0x80 (3 bytes)
[    2.156737] mmc2: queuing unknown CIS tuple 0x80 (3 bytes)
[    2.167375] mmc2: queuing unknown CIS tuple 0x80 (7 bytes)
[    2.174607] mmc2: queuing unknown CIS tuple 0x80 (3 bytes)
[    2.182808] mmc2: queuing unknown CIS tuple 0x80 (6 bytes)
[    2.191358] mmc3: SDHCI controller on 219c000.usdhc [219c000.usdhc] using ADMA
[    2.201297] NET: Registered protocol family 26
[    2.206035] NET: Registered protocol family 17
[    2.210560] 8021q: 802.1Q VLAN Support v1.8
[    2.225049] cpu cpu0: dev_pm_opp_get_opp_count: OPP table not found (-19)
[    2.234267] cpu cpu0: Registered imx6q-cpufreq
[    2.265262] imx_thermal 2000000.aips-bus:tempmon: Extended Commercial CPU temperature grade - max:105C critical:100C passive:95C
[    2.277486] ubi0: attaching mtd2
[    2.299954] random: crng init done
[    2.398177] mmc2: new high speed SDIO card at address 0001
[    4.338619] ubi0: scanning is finished
[    4.368853] ubi0: attached mtd2 (name "data", size 509 MiB)
[    4.374594] ubi0: PEB size: 131072 bytes (128 KiB), LEB size: 126976 bytes
[    4.381533] ubi0: min./max. I/O unit sizes: 2048/2048, sub-page size 2048
[    4.388338] ubi0: VID header offset: 2048 (aligned 2048), data offset: 4096
[    4.395347] ubi0: good PEBs: 4066, bad PEBs: 6, corrupted PEBs: 0
[    4.401487] ubi0: user volume: 5, internal volumes: 1, max. volumes count: 128
[    4.408729] ubi0: max/mean erase counter: 1/0, WL threshold: 4096, image sequence number: 850540274
[    4.417918] ubi0: available PEBs: 171, total reserved PEBs: 3895, PEBs reserved for bad PEB handling: 74
[    4.427484] ubi0: background thread "ubi_bgt0d" started, PID 81
[    4.435298] input: gpio-inputs as /devices/soc0/gpio-inputs/input/input2
[    4.444157] rtc-pcf85063 2-0051: setting system clock to 2021-09-10 04:27:10 UTC (1631248030)

But if we disconnect 50MHz generator from MX6SX_PAD_ENET1_TX_CLK__ENET1_REF_CLK1 of iMX6, kernel continues to boot normally!

Could you please help solving this issue?

Thanks

[texnikk]

Here is log of continued boot:

[    4.435298] input: gpio-inputs as /devices/soc0/gpio-inputs/input/input2
[    4.444157] rtc-pcf85063 2-0051: setting system clock to 2021-09-10 04:27:10 UTC (1631248030)
?[ 1043.965087] UBIFS (ubi0:3): UBIFS: mounted UBI device 0, volume 3, name "boot1", R/O mode
[ 1043.973325] UBIFS (ubi0:3): LEB size: 126976 bytes (124 KiB), min./max. I/O unit sizes: 2048 bytes/2048 bytes
[ 1043.983268] UBIFS (ubi0:3): FS size: 217636864 bytes (207 MiB, 1714 LEBs), journal size 10919936 bytes (10 MiB, 86 LEBs)
[ 1043.994205] UBIFS (ubi0:3): reserved for root: 4952683 bytes (4836 KiB)
[ 1044.002954] UBIFS (ubi0:3): media format: w4/r0 (latest is w4/r0), UUID 12885A88-0B42-4A8E-B319-D10178ACB240, small LPT model
[ 1044.027415] VFS: Mounted root (ubifs filesystem) readonly on device 0:12.
[ 1044.037133] devtmpfs: mounted
[ 1044.045336] Freeing unused kernel memory: 1024K (80800000 - 80900000)
[ 1044.369208] UBIFS (ubi0:1): background thread "ubifs_bgt0_1" started, PID 84
[ 1044.447424] UBIFS (ubi0:1): recovery needed
[ 1044.771026] UBIFS (ubi0:1): recovery completed
[ 1044.775970] UBIFS (ubi0:1): UBIFS: mounted UBI device 0, volume 1, name "log"
[ 1044.783178] UBIFS (ubi0:1): LEB size: 126976 bytes (124 KiB), min./max. I/O unit sizes: 2048 bytes/2048 bytes
[ 1044.793150] UBIFS (ubi0:1): FS size: 9269248 bytes (8 MiB, 73 LEBs), journal size 1015809 bytes (0 MiB, 6 LEBs)
[ 1044.803344] UBIFS (ubi0:1): reserved for root: 437809 bytes (427 KiB)
[ 1044.809812] UBIFS (ubi0:1): media format: w4/r0 (latest is w4/r0), UUID C67164B9-5E1C-4DF9-8038-092EAC75E679, small LPT model
[ 1046.362216] cgroup: cgroup2: unknown option "nsdelegate"
[ 1046.402149] systemd[1]: systemd 240 running in system mode. (-PAM -AUDIT -SELINUX -IMA -APPARMOR -SMACK +SYSVINIT +UTMP -LIBCRYPTSETUP -GCRYPT -GNUTLS 
-ACL -XZ -LZ4 -SECCOMP +BLKID -ELFUTILS +KMOD -IDN2 -IDN -PCRE2 default-hierarchy=hybrid)
[ 1046.424179] systemd[1]: Detected architecture arm.