Re: [PATCH RESEND v2 1/2] clk: core: Honor CLK_OPS_PARENT_ENABLE for clk gate ops

Alexander Stein
2022-08-26T12:28:17Z

Hi everybody,

Am Montag, 22. August 2022, 10:14:23 CEST schrieb Chen-Yu Tsai:
> In the previous commits that added CLK_OPS_PARENT_ENABLE, support for
> this flag was only added to rate change operations (rate setting and
> reparent) and disabling unused subtree. It was not added to the
> clock gate related operations. Any hardware driver that needs it for
> these operations will either see bogus results, or worse, hang.
>
> This has been seen on MT8192 and MT8195, where the imp_ii2_* clk
> drivers set this, but dumping debugfs clk_summary would cause it
> to hang.
>
> Fixes: fc8726a2c021 ("clk: core: support clocks which requires parents
> enable (part 2)") Fixes: a4b3518d146f ("clk: core: support clocks which
> requires parents enable (part 1)") Signed-off-by: Chen-Yu Tsai
> <wenst@chromium.org>
> Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
> Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
> ---
> drivers/clk/clk.c | 28 ++++++++++++++++++++++++++++
> 1 file changed, 28 insertions(+)
>
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 7fc191c15507..9b365cd6d14b 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -196,6 +196,9 @@ static bool clk_core_rate_is_protected(struct clk_core
> *core) return core->protect_count;
> }
>
> +static int clk_core_prepare_enable(struct clk_core *core);
> +static void clk_core_disable_unprepare(struct clk_core *core);
> +
> static bool clk_core_is_prepared(struct clk_core *core)
> {
> bool ret = false;
> @@ -208,7 +211,11 @@ static bool clk_core_is_prepared(struct clk_core *core)
> return core->prepare_count;
>
> if (!clk_pm_runtime_get(core)) {
> + if (core->flags & CLK_OPS_PARENT_ENABLE)
> + clk_core_prepare_enable(core->parent);
> ret = core->ops->is_prepared(core->hw);
> + if (core->flags & CLK_OPS_PARENT_ENABLE)
> + clk_core_disable_unprepare(core->parent);
> clk_pm_runtime_put(core);
> }
>
> @@ -244,7 +251,13 @@ static bool clk_core_is_enabled(struct clk_core *core)
> }
> }
>
> + if (core->flags & CLK_OPS_PARENT_ENABLE)
> + clk_core_prepare_enable(core->parent);
> +
> ret = core->ops->is_enabled(core->hw);
> +
> + if (core->flags & CLK_OPS_PARENT_ENABLE)
> + clk_core_disable_unprepare(core->parent);
> done:
> if (core->rpm_enabled)
> pm_runtime_put(core->dev);
> @@ -812,6 +825,9 @@ int clk_rate_exclusive_get(struct clk *clk)
> }
> EXPORT_SYMBOL_GPL(clk_rate_exclusive_get);
>
> +static int clk_core_enable_lock(struct clk_core *core);
> +static void clk_core_disable_lock(struct clk_core *core);
> +
> static void clk_core_unprepare(struct clk_core *core)
> {
> lockdep_assert_held(&prepare_lock);
> @@ -835,6 +851,9 @@ static void clk_core_unprepare(struct clk_core *core)
>
> WARN(core->enable_count > 0, "Unpreparing enabled %s\n", core-
>name);
>
> + if (core->flags & CLK_OPS_PARENT_ENABLE)
> + clk_core_enable_lock(core->parent);
> +
> trace_clk_unprepare(core);
>
> if (core->ops->unprepare)
> @@ -843,6 +862,9 @@ static void clk_core_unprepare(struct clk_core *core)
> clk_pm_runtime_put(core);
>
> trace_clk_unprepare_complete(core);
> +
> + if (core->flags & CLK_OPS_PARENT_ENABLE)
> + clk_core_disable_lock(core->parent);
> clk_core_unprepare(core->parent);
> }
>
> @@ -891,6 +913,9 @@ static int clk_core_prepare(struct clk_core *core)
> if (ret)
> goto runtime_put;
>
> + if (core->flags & CLK_OPS_PARENT_ENABLE)
> + clk_core_enable_lock(core->parent);
> +
> trace_clk_prepare(core);
>
> if (core->ops->prepare)
> @@ -898,6 +923,9 @@ static int clk_core_prepare(struct clk_core *core)
>
> trace_clk_prepare_complete(core);
>
> + if (core->flags & CLK_OPS_PARENT_ENABLE)
> + clk_core_disable_lock(core->parent);
> +
> if (ret)
> goto unprepare;
> }

Unfortunately this completely locks up my i.MX8M Plus based board during early
boot.
I'm currently running on next-20220826 using arch/arm64/boot/dts/freescale/
imx8mp-tqma8mpql-mba8mpxl.dts
Reverting this patch gets my board booting again. dmesg until hard lockup
below.

Best regards,
Alexander

[ 0.000000] Booting Linux on physical CPU 0x0000000000 [0x410fd034]
[ 0.000000] Linux version 6.0.0-rc2-next-20220826 (steina@steina-w)
(aarch64-v8a-linux-gnu-gcc (OSELAS.Toolchain-2020.08.0 10-2020
0822) 10.2.1 20200822, GNU ld (GNU Binutils) 2.35) #603 SMP PREEMPT Fri Aug 26
14:25:05 CEST 2022
[ 0.000000] Machine model: TQ-Systems i.MX8MPlus TQMa8MPxL on MBa8MPxL
[ 0.000000] earlycon: ec_imx6q0 at MMIO 0x0000000030a60000 (options
'115200')
[ 0.000000] printk: bootconsole [ec_imx6q0] enabled
[ 0.000000] efi: UEFI not found.
[ 0.000000] Reserved memory: created CMA memory pool at 0x000000005a400000,
size 896 MiB
[ 0.000000] OF: reserved mem: initialized node linux,cma, compatible id
shared-dma-pool
[ 0.000000] NUMA: No NUMA configuration found
[ 0.000000] NUMA: Faking a node at [mem
0x0000000040000000-0x00000000bfffffff]
[ 0.000000] NUMA: NODE_DATA [mem 0xbfbd6b00-0xbfbd8fff]
[ 0.000000] Zone ranges:
[ 0.000000] DMA [mem 0x0000000040000000-0x00000000bfffffff]
[ 0.000000] DMA32 empty
[ 0.000000] Normal empty
[ 0.000000] Movable zone start for each node
[ 0.000000] Early memory node ranges
[ 0.000000] node 0: [mem 0x0000000040000000-0x00000000923fffff]
[ 0.000000] node 0: [mem 0x0000000092400000-0x00000000943fffff]
[ 0.000000] node 0: [mem 0x0000000094400000-0x00000000bfffffff]
[ 0.000000] Initmem setup node 0 [mem
0x0000000040000000-0x00000000bfffffff]
[ 0.000000] psci: probing for conduit method from DT.
[ 0.000000] psci: PSCIv1.1 detected in firmware.
[ 0.000000] psci: Using standard PSCI v0.2 function IDs
[ 0.000000] psci: MIGRATE_INFO_TYPE not supported.
[ 0.000000] psci: SMC Calling Convention v1.1
[ 0.000000] percpu: Embedded 19 pages/cpu s38376 r8192 d31256 u77824
[ 0.000000] Detected VIPT I-cache on CPU0
[ 0.000000] CPU features: detected: GIC system register CPU interface
[ 0.000000] CPU features: detected: ARM erratum 845719
[ 0.000000] Fallback order for Node 0: 0
[ 0.000000] Built 1 zonelists, mobility grouping on. Total pages: 516096
[ 0.000000] Policy zone: DMA
[ 0.000000] Kernel command line: root=/dev/nfs rw nfsroot=192.168.0.101:/
srv/tftp/imx8_mainline,v3,tcp ip=192.168.0.100:192.168.0.
101::::eth0:off console=ttymxc3,115200 earlycon=ec_imx6q,0x30A60000,115200
[ 0.000000] Dentry cache hash table entries: 262144 (order: 9, 2097152
bytes, linear)
[ 0.000000] Inode-cache hash table entries: 131072 (order: 8, 1048576
bytes, linear)
[ 0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off
[ 0.000000] Memory: 1077444K/2097152K available (14144K kernel code, 2206K
rwdata, 6596K rodata, 5376K init, 519K bss, 102204K res
erved, 917504K cma-reserved)
[ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
[ 0.000000] rcu: Preemptible hierarchical RCU implementation.
[ 0.000000] rcu: RCU event tracing is enabled.
[ 0.000000] rcu: RCU restricting CPUs from NR_CPUS=256 to nr_cpu_ids=4.
[ 0.000000] Trampoline variant of Tasks RCU enabled.
[ 0.000000] Tracing variant of Tasks RCU enabled.
[ 0.000000] rcu: RCU calculated value of scheduler-enlistment delay is 25
jiffies.
[ 0.000000] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=4
[ 0.000000] NR_IRQS: 64, nr_irqs: 64, preallocated irqs: 0
[ 0.000000] GICv3: GIC: Using split EOI/Deactivate mode
[ 0.000000] GICv3: 160 SPIs implemented
[ 0.000000] GICv3: 0 Extended SPIs implemented
[ 0.000000] Root IRQ handler: gic_handle_irq
[ 0.000000] GICv3: GICv3 features: 16 PPIs
[ 0.000000] GICv3: CPU0: found redistributor 0 region 0:0x0000000038880000
[ 0.000000] ITS: No ITS available, not enabling LPIs
[ 0.000000] rcu: srcu_init: Setting srcu_struct sizes based on contention.
[ 0.000000] arch_timer: cp15 timer(s) running at 8.00MHz (phys).
[ 0.000000] clocksource: arch_sys_counter: mask: 0xffffffffffffff
max_cycles: 0x1d854df40, max_idle_ns: 440795202120 ns
[ 0.000000] sched_clock: 56 bits at 8MHz, resolution 125ns, wraps every
2199023255500ns
[ 0.008368] Console: colour dummy device 80x25
[ 0.012575] Calibrating delay loop (skipped), value calculated using timer
frequency.. 16.00 BogoMIPS (lpj=32000)
[ 0.022844] pid_max: default: 32768 minimum: 301
[ 0.027538] LSM: Security Framework initializing
[ 0.032209] Mount-cache hash table entries: 4096 (order: 3, 32768 bytes,
linear)
[ 0.039560] Mountpoint-cache hash table entries: 4096 (order: 3, 32768
bytes, linear)
[ 0.048701] cblist_init_generic: Setting adjustable number of callback
queues.
[ 0.054720] cblist_init_generic: Setting shift to 2 and lim to 1.
[ 0.060880] cblist_init_generic: Setting shift to 2 and lim to 1.
[ 0.067086] rcu: Hierarchical SRCU implementation.
[ 0.071761] rcu: Max phase no-delay instances is 1000.
[ 0.078123] EFI services will not be available.
[ 0.081907] smp: Bringing up secondary CPUs ...
[ 0.086553] Detected VIPT I-cache on CPU1
[ 0.086639] GICv3: CPU1: found redistributor 1 region 0:0x00000000388a0000
[ 0.086675] CPU1: Booted secondary processor 0x0000000001 [0x410fd034]
[ 0.087141] Detected VIPT I-cache on CPU2
[ 0.087209] GICv3: CPU2: found redistributor 2 region 0:0x00000000388c0000
[ 0.087229] CPU2: Booted secondary processor 0x0000000002 [0x410fd034]
[ 0.087664] Detected VIPT I-cache on CPU3
[ 0.087735] GICv3: CPU3: found redistributor 3 region 0:0x00000000388e0000
[ 0.087754] CPU3: Booted secondary processor 0x0000000003 [0x410fd034]
[ 0.087819] smp: Brought up 1 node, 4 CPUs
[ 0.142729] SMP: Total of 4 processors activated.
[ 0.147444] CPU features: detected: 32-bit EL0 Support
[ 0.152623] CPU features: detected: CRC32 instructions
[ 0.157983] CPU: All CPU(s) started at EL2
[ 0.161908] alternatives: patching kernel code
[ 0.167362] devtmpfs: initialized
[ 0.175779] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff,
max_idle_ns: 7645041785100000 ns
[ 0.182756] futex hash table entries: 1024 (order: 4, 65536 bytes, linear)
[ 0.213470] pinctrl core: initialized pinctrl subsystem
[ 0.217757] DMI not present or invalid.
[ 0.220335] NET: Registered PF_NETLINK/PF_ROUTE protocol family
[ 0.226544] DMA: preallocated 256 KiB GFP_KERNEL pool for atomic
allocations
[ 0.232875] DMA: preallocated 256 KiB GFP_KERNEL|GFP_DMA pool for atomic
allocations
[ 0.240685] DMA: preallocated 256 KiB GFP_KERNEL|GFP_DMA32 pool for atomic
allocations
[ 0.248550] audit: initializing netlink subsys (disabled)
[ 0.254096] audit: type=2000 audit(0.180:1): state=initialized
audit_enabled=0 res=1
[ 0.254516] thermal_sys: Registered thermal governor 'bang_bang'
[ 0.261730] thermal_sys: Registered thermal governor 'step_wise'
[ 0.267761] thermal_sys: Registered thermal governor 'power_allocator'
[ 0.273829] cpuidle: using governor menu
[ 0.284458] hw-breakpoint: found 6 breakpoint and 4 watchpoint registers.
[ 0.291197] ASID allocator initialised with 65536 entries
[ 0.297274] Serial: AMBA PL011 UART driver
[ 0.307172] imx8mp-pinctrl 30330000.pinctrl: initialized IMX pinctrl driver
[ 0.323077] KASLR disabled due to lack of seed
[ 0.333413] HugeTLB: registered 1.00 GiB page size, pre-allocated 0 pages
[ 0.337396] HugeTLB: 16380 KiB vmemmap can be freed for a 1.00 GiB page
[ 0.344066] HugeTLB: registered 32.0 MiB page size, pre-allocated 0 pages
[ 0.350860] HugeTLB: 508 KiB vmemmap can be freed for a 32.0 MiB page
[ 0.357335] HugeTLB: registered 2.00 MiB page size, pre-allocated 0 pages
[ 0.364157] HugeTLB: 28 KiB vmemmap can be freed for a 2.00 MiB page
[ 0.370546] HugeTLB: registered 64.0 KiB page size, pre-allocated 0 pages
[ 0.377372] HugeTLB: 0 KiB vmemmap can be freed for a 64.0 KiB page
[ 0.384224] cryptd: max_cpu_qlen set to 1000
[ 0.390062] iommu: Default domain type: Translated
[ 0.392886] iommu: DMA domain TLB invalidation policy: strict mode
[ 0.399407] SCSI subsystem initialized
[ 0.403223] usbcore: registered new interface driver usbfs
[ 0.408468] usbcore: registered new interface driver hub
[ 0.413793] usbcore: registered new device driver usb
[ 0.419379] mc: Linux media interface: v0.10
[ 0.423158] videodev: Linux video capture interface: v2.00
[ 0.428668] pps_core: LinuxPPS API ver. 1 registered
[ 0.433635] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo
Giometti <giometti@linux.it>
[ 0.442834] PTP clock support registered
[ 0.446880] EDAC MC: Ver: 3.0.0
[ 0.450601] FPGA manager framework
[ 0.453404] Advanced Linux Sound Architecture Driver Initialized.
[ 0.460221] vgaarb: loaded
[ 0.462422] clocksource: Switched to clocksource arch_sys_counter
[ 0.468465] VFS: Disk quotas dquot_6.6.0
[ 0.472258] VFS: Dquot-cache hash table entries: 512 (order 0, 4096 bytes)
[ 0.485904] NET: Registered PF_INET protocol family
[ 0.488099] IP idents hash table entries: 32768 (order: 6, 262144 bytes,
linear)
[ 0.496889] tcp_listen_portaddr_hash hash table entries: 1024 (order: 2,
16384 bytes, linear)
[ 0.504019] Table-perturb hash table entries: 65536 (order: 6, 262144
bytes, linear)
[ 0.511764] TCP established hash table entries: 16384 (order: 5, 131072
bytes, linear)
[ 0.519819] TCP bind hash table entries: 16384 (order: 7, 524288 bytes,
linear)
[ 0.527471] TCP: Hash tables configured (established 16384 bind 16384)
[ 0.533730] UDP hash table entries: 1024 (order: 3, 32768 bytes, linear)
[ 0.540415] UDP-Lite hash table entries: 1024 (order: 3, 32768 bytes,
linear)
[ 0.547696] NET: Registered PF_UNIX/PF_LOCAL protocol family
[ 0.553577] RPC: Registered named UNIX socket transport module.
[ 0.559190] RPC: Registered udp transport module.
[ 0.563903] RPC: Registered tcp transport module.
[ 0.568627] RPC: Registered tcp NFSv4.1 backchannel transport module.
[ 0.575107] PCI: CLS 0 bytes, default 64
[ 0.579612] hw perfevents: enabled with armv8_cortex_a53 PMU driver, 7
counters available
[ 0.588770] Initialise system trusted keyrings
[ 0.591888] workingset: timestamp_bits=42 max_order=19 bucket_order=0
[ 0.605043] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[ 0.608686] NFS: Registering the id_resolver key type
[ 0.613155] Key type id_resolver registered
[ 0.617328] Key type id_legacy registered
[ 0.621432] nfs4filelayout_init: NFSv4 File Layout Driver Registering...
[ 0.628089] nfs4flexfilelayout_init: NFSv4 Flexfile Layout Driver
Registering...
[ 0.671152] Key type asymmetric registered
[ 0.672397] Asymmetric key parser 'x509' registered
[ 0.677336] Block layer SCSI generic (bsg) driver version 0.4 loaded (major
243)
[ 0.684742] io scheduler mq-deadline registered
[ 0.689290] io scheduler kyber registered