Re: [PATCH] clk: imx7d: do not set the parent of IMX7D_ENET_AXI_ROOT_SRC

[Stephen Boyd <sboyd@codeaurora.org>]

On 08/10, Fabio Estevam wrote:
> Hi Mike,
> 
> On Fri, Jul 15, 2016 at 10:53 AM, Fabio Estevam <fabio.estevam@nxp.com> wrote:
> > Booting the kernel on a imx7s-warp leads to several warnings like these:
> >
> > [    0.000000] ------------[ cut here ]------------
> > [    0.000000] WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3536 lock_release+0x2f8/0x330
> > [    0.000000] releasing a pinned lock
> >
> > [    0.000000] ------------[ cut here ]------------
> > [    0.000000] WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:2722 trace_hardirqs_on_caller+0x1ac/0x1f4
> > [    0.000000] DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled))
> >
> > [    0.000000] ---[ end trace cb88537fdc8fa201 ]---
> > [    0.000000] bad: scheduling from the idle thread!
> > [    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G        W       4.7.0-rc7-next-20160715 #404
> >
> > [    0.000000] ------------[ cut here ]------------
> > [    0.000000] WARNING: CPU: 0 PID: 0 at kernel/time/sched_clock.c:179 sched_clock_register+0x44/0x1f8
> > [    0.000000] Modules linked in:
> >
> > [    0.000591] ------------[ cut here ]------------
> > [    0.000610] WARNING: CPU: 0 PID: 0 at kernel/time/sched_clock.c:179 sched_clock_register+0x44/0x1f8
> >
> > [    0.002084] ------------[ cut here ]------------
> > [    0.002104] WARNING: CPU: 0 PID: 0 at init/main.c:576 start_kernel+0x258/0x3b0
> > [    0.002114] Interrupts were enabled early
> >
> >
> > This fix is along the same lines as 5e33ebff7edd ("clk: imx7d: do not
> > set parent of ethernet time/ref clocks") and the explanation from that
> > commit is:
> >
> > "The reason for the warning is that setting the parent enables the ENET
> >  PLL since we are using CLK_OPS_PARENT_ENABLE. Enabling the ENET PLL can
> >  cause clk_pllv3_wait_lock to sleep. See also:
> >  commit fc8726a2c021 ("clk: core: support clocks which requires parents
> >  enable (part 2)")."
> >
> > imx7s-warp does not even use the FEC interface, so we should not really
> > configure the parent of IMX7D_ENET_AXI_ROOT_SRC in the common MX7 clock
> > driver code.
> >
> > The dts file should use the assigned-clocks/assigned-clock-parents method,
> > so simply remove the configuration of IMX7D_ENET_AXI_ROOT_SRC parent.
> >
> > Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
> 
> Do you think this one could be applied to 4.8-rc?
>

Is there a "Fixes:" tag that can be applied here? Does this
depend on some sort of DTS changes to add assigned clocks and
parents?

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