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Date:   Wed, 10 Aug 2022 11:56:46 -0700
From:   Nathan Chancellor <nathan@kernel.org>
To:     Conor.Dooley@microchip.com
Cc:     ndesaulniers@google.com, llvm@lists.linux.dev,
        mturquette@baylibre.com, sboyd@kernel.org, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, paul.walmsley@sifive.com,
        aou@eecs.berkeley.edu, linux-clk@vger.kernel.org,
        devicetree@vger.kernel.org, p.zabel@pengutronix.de,
        linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
        Daire.McNamara@microchip.com, palmer@dabbelt.com
Subject: Re: [PATCH v2 00/12] PolarFire SoC reset controller & clock cleanups
Message-ID: <YvP/bjh+wXihlrdG@dev-arch.thelio-3990X>
References: <20220704121558.2088698-1-conor.dooley@microchip.com>
 <bd14f1a2-750d-2511-df0a-85a9f5925f84@microchip.com>
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Hi Conor,

On Tue, Aug 09, 2022 at 11:05:32PM +0000, Conor.Dooley@microchip.com wrote:
> +CC clang people :)
> 
> Got an odd one here and would appreciate some pointers for where to
> look. This code when built with gcc boots fine, for example with:
> riscv64-unknown-linux-gnu-gcc (g5964b5cd727) 11.1.0
> The same code but build with clang build it fails to boot but prior to
> that applying this patchset it boots fine. Specifically it is the patch
> "clk: microchip: mpfs: move id & offset out of clock structs"
> 
> I applied this patchset on top of tonight's master (15205c2829ca) but
> I've been seeing the same problem for a few weeks on -next too. I tried
> the following 2 versions of clang/llvm:
> ClangBuiltLinux clang version 15.0.0 (5b0788fef86ed7008a11f6ee19b9d86d42b6fcfa), LLD 15.0.0
> ClangBuiltLinux clang version 15.0.0 (bab8af8ea062f6332b5c5d13ae688bb8900f244a), LLD 15.0.0

Good to know that it reproduces with fairly recent versions of LLVM :)

> It's probably something silly that I've overlooked but I am not au
> fait with these sort of things unfortunately, but hey - at least I'll
> learn something then.

I took a quick glance at the patch you mentioned above and I don't
immediately see anything as problematic... I was going to see if I could
reproduce this locally in QEMU since I do see there is a machine
'microchip-icicle-kit' but I am not having much success getting the
machine past SBI. Does this reproduce in QEMU or are you working with
the real hardware? If QEMU, do you happen to have a working invocation
handy?

Cheers,
Nathan

> The boot log is fairly short so here ya go:
> 
> [    0.000000] Linux version 5.19.0-13253-g374b508ee318 (conor@spud) (ClangBuiltLinux clang version 15.0.0 (git@g
> ithub.com:llvm/llvm-project.git 5b0788fef86ed7008a11f6ee19b9d86d42b6fcfa), LLD 15.0.0) #1 SMP Tue Aug 9 22:42:10 IST 
> 2022
> [    0.000000] OF: fdt: Ignoring memory range 0x80000000 - 0x80200000
> [    0.000000] Machine model: Microchip PolarFire-SoC Icicle Kit
> [    0.000000] earlycon: ns16550a0 at MMIO32 0x0000000020100000 (options '115200n8')
> [    0.000000] printk: bootconsole [ns16550a0] enabled
> [    0.000000] efi: UEFI not found.
> [    0.000000] Zone ranges:
> [    0.000000]   DMA32    [mem 0x0000000080200000-0x00000000ffffffff]
> [    0.000000]   Normal   [mem 0x0000000100000000-0x000000103fffffff]
> [    0.000000] Movable zone start for each node
> [    0.000000] Early memory node ranges
> [    0.000000]   node   0: [mem 0x0000000080200000-0x00000000adffffff]
> [    0.000000]   node   0: [mem 0x0000001000000000-0x000000103fffffff]
> [    0.000000] Initmem setup node 0 [mem 0x0000000080200000-0x000000103fffffff]
> [    0.000000] On node 0, zone Normal: 16064512 pages in unavailable ranges
> [    0.000000] SBI specification v0.3 detected
> [    0.000000] SBI implementation ID=0x1 Version=0x9
> [    0.000000] SBI TIME extension detected
> [    0.000000] SBI IPI extension detected
> [    0.000000] SBI RFENCE extension detected
> [    0.000000] SBI HSM extension detected
> [    0.000000] CPU with hartid=0 is not available
> [    0.000000] CPU with hartid=0 is not available
> [    0.000000] riscv: base ISA extensions acdfim
> [    0.000000] riscv: ELF capabilities acdfim
> [    0.000000] percpu: Embedded 18 pages/cpu s34168 r8192 d31368 u73728
> [    0.000000] pcpu-alloc: s34168 r8192 d31368 u73728 alloc=18*4096
> [    0.000000] pcpu-alloc: [0] 0 [0] 1 [0] 2 [0] 3
> [    0.000000] CPU node for /cpus/cpu@0 exist but the possible cpu range is :0-3
> [    0.000000] Built 1 zonelists, mobility grouping on.  Total pages: 224263
> [    0.000000] Kernel command line: root=/dev/nfs ip=dhcp debug nfsroot=192.168.2.5:/stuff/nfs_share earlycon
> [    0.000000] Dentry cache hash table entries: 131072 (order: 8, 1048576 bytes, linear)
> [    0.000000] Inode-cache hash table entries: 65536 (order: 7, 524288 bytes, linear)
> [    0.000000] mem auto-init: stack:all(zero), heap alloc:off, heap free:off
> [    0.000000] software IO TLB: area num 4.
> [    0.000000] software IO TLB: mapped [mem 0x00000000aa000000-0x00000000ae000000] (64MB)
> [    0.000000] Virtual kernel memory layout:
> [    0.000000]       fixmap : 0xffffffc6fee00000 - 0xffffffc6ff000000   (2048 kB)
> [    0.000000]       pci io : 0xffffffc6ff000000 - 0xffffffc700000000   (  16 MB)
> [    0.000000]      vmemmap : 0xffffffc700000000 - 0xffffffc800000000   (4096 MB)
> [    0.000000]      vmalloc : 0xffffffc800000000 - 0xffffffd800000000   (  64 GB)
> [    0.000000]       lowmem : 0xffffffd800000000 - 0xffffffe7bfe00000   (  62 GB)
> [    0.000000]       kernel : 0xffffffff80000000 - 0xffffffffffffffff   (2047 MB)
> [    0.000000] Memory: 803032K/1800192K available (7485K kernel code, 2858K rwdata, 4096K rodata, 2181K init, 394K bss, 997160K reserved, 0K cma-reserved)
> [    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
> [    0.000000] rcu: Hierarchical RCU implementation.
> [    0.000000] rcu:     RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=4.
> [    0.000000] rcu:     RCU debug extended QS entry/exit.
> [    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] CPU with hartid=0 is not available
> [    0.000000] riscv-intc: unable to find hart id for /cpus/cpu@0/interrupt-controller
> [    0.000000] riscv-intc: 64 local interrupts mapped
> [    0.000000] plic: interrupt-controller@c000000: mapped 186 interrupts with 4 handlers for 9 contexts.
> [    0.000000] rcu: srcu_init: Setting srcu_struct sizes based on contention.
> [    0.000000] riscv_timer_init_dt: Registering clocksource cpuid [0] hartid [4]
> [    0.000000] clocksource: riscv_clocksource: mask: 0xffffffffffffffff max_cycles: 0x1d854df40, max_idle_ns: 3526361616960 ns
> [    0.000003] sched_clock: 64 bits at 1000kHz, resolution 1000ns, wraps every 2199023255500ns
> [    0.009713] Console: colour dummy device 80x25
> [    0.014676] printk: console [tty0] enabled
> [    0.019217] printk: bootconsole [ns16550a0] disabled
> 
> FWIW this is right about when the clock driver gets loaded
> as you might imagine.
> 
> My config is here, but it's been reproduced on a few different
> defconfigs:
> https://raw.githubusercontent.com/ConchuOD/polarfire-soc-buildroot-sdk/dev/conf/lowmem/defconfig
> 
> On 04/07/2022 13:15, Conor Dooley wrote:
> > Hey all,
> > I know I have not sat on the RFC I sent about the aux. bus parts
> > for too long, but figured I'd just send the whole thing anyway to all
> > lists etc.
> > 
> > Kinda two things happening in this series, but I sent it together to
> > ensure the second part would apply correctly.
> > 
> > The first is the reset controller that I promised after discovering the
> > issue triggered by CONFIG_PM & the phy not coming up correctly. I have
> > now removed all the messing with resets from clock enable/disable
> > functions & now use the aux bus to set up a reset controller driver.
> > Since I needed something to test it, I hooked up the reset for the
> > Cadence MACB on PolarFire SoC. This has been split into a second series
> > for v2:
> > https://lore.kernel.org/all/20220704114511.1892332-1-conor.dooley@microchip.com/
> > 
> > The second part adds rate control for the MSS PLL clock, followed by
> > some simplifications to the driver & conversions of some custom structs
> > to the corresponding structs in the framework.
> > 
> > Thanks,
> > Conor.
> > 
> > Changes since v1:
> > - split off the net patches
> > - clk: actually pass the spinlock to the converted dividers & gates
> > - reset: added a spinlock around RMW access to registers
> > - reset: switched to BIT(i) macros
> > - reset: used local copies of some variables as pointed out by Philipp
> > - reset: dropped the success printout
> > 
> > Conor Dooley (12):
> >   dt-bindings: clk: microchip: mpfs: add reset controller support
> >   clk: microchip: mpfs: add reset controller
> >   reset: add polarfire soc reset support
> >   MAINTAINERS: add polarfire soc reset controller
> >   riscv: dts: microchip: add mpfs specific macb reset support
> >   clk: microchip: mpfs: add module_authors entries
> >   clk: microchip: mpfs: add MSS pll's set & round rate
> >   clk: microchip: mpfs: move id & offset out of clock structs
> >   clk: microchip: mpfs: simplify control reg access
> >   clk: microchip: mpfs: delete 2 line mpfs_clk_register_foo()
> >   clk: microchip: mpfs: convert cfg_clk to clk_divider
> >   clk: microchip: mpfs: convert periph_clk to clk_gate
> > 
> >  .../bindings/clock/microchip,mpfs.yaml        |  17 +-
> >  MAINTAINERS                                   |   1 +
> >  arch/riscv/boot/dts/microchip/mpfs.dtsi       |   7 +-
> >  drivers/clk/microchip/Kconfig                 |   1 +
> >  drivers/clk/microchip/clk-mpfs.c              | 379 +++++++++---------
> >  drivers/reset/Kconfig                         |   7 +
> >  drivers/reset/Makefile                        |   2 +-
> >  drivers/reset/reset-mpfs.c                    | 157 ++++++++
> >  include/soc/microchip/mpfs.h                  |   8 +
> >  9 files changed, 386 insertions(+), 193 deletions(-)
> >  create mode 100644 drivers/reset/reset-mpfs.c
> > 
> > 
> > base-commit: b13baccc3850ca8b8cccbf8ed9912dbaa0fdf7f3