[PATCH/RFC] ARM: shmobile: r8a7779: Update early timer initialisation order

[Simon Horman]

On Fri, Aug 09, 2013 at 05:37:39PM +0900, Magnus Damm wrote:
> On Thu, Aug 8, 2013 at 5:59 PM, Simon Horman <horms+renesas at verge.net.au> wrote:
> > a894fcc2d01a89e6fe3da0845a4d80a5312e1124 ("ARM: smp_twd: Divorce smp_twd
> > from local timer API") altered twd_local_timer_common_register() so that it
> > may make use of late_timer_init.
> >
> > This is problematic on marzen with Magnus's recent patch "ARM: shmobile:
> > marzen: Switch to DT_MACHINE_START" which switches marzen around to enable
> > USE_OF and thus shmobile_timer_init(), which is registered as
> > late_time_init by shmobile_earlytimer_init() stops being a no-op.
> >
> > As a work-around I have updated r8a7779_earlytimer_init() so that
> > shmobile_earlytimer_init() is called after r8a7779_register_twd().
> > Or in other words, the shmobile_earlytimer_init() setting of
> > late_time_init overwrites that of twd_local_timer_common_register().
> >
> > Cc: Stephen Boyd <sboyd at codeaurora.org>
> > Cc: Magnus Damm <magnus.damm at gmail.com>
> > Signed-off-by: Simon Horman <horms+renesas at verge.net.au>
> >
> > ---
> >
> > This patch was created on top of a merge of next-20130807 from the
> > linux-next tree and renesas-next-20130807 from my renesas tree.
> >
> > I expect the problem describe above to be present in the
> > next version of linux-next as it will include renesas-next-20130807.
> >
> > I rather suspect that this fix is just papers over the problem
> > at hand rather than fixing it. But it does at least fix the problem
> > to the extent where the marzen board at least boots.
> >
> > For reference the output of /proc/interrupts after such a boot is below.
> >
> >             CPU0       CPU1       CPU2       CPU3
> >   29:          0       9365       9363       9359       GIC   29  twd
> >   59:          0          0          0          0       GIC   59  renesas_intc_irqpin.0
> >   60:          5          0          0          0       GIC   60  renesas_intc_irqpin.0
> >   61:          0          0          0          0       GIC   61  renesas_intc_irqpin.0
> >   62:          0          0          0          0       GIC   62  renesas_intc_irqpin.0
> >   64:        278          0          0          0       GIC   64  sh_tmu.0
> >   76:          1          0          0          0       GIC   76  ehci_hcd:usb1, ohci_hcd:usb3
> >   77:          1          0          0          0       GIC   77  ehci_hcd:usb2, ohci_hcd:usb4
> >  111:          0          0          0          0       GIC  111  i2c-rcar.0
> >  112:          0          0          0          0       GIC  112  i2c-rcar.2
> >  113:          0          0          0          0       GIC  113  i2c-rcar.3
> >  114:          0          0          0          0       GIC  114  i2c-rcar.1
> >  122:         45          0          0          0       GIC  122  sh-sci.2:mux
> >  132:          0          0          0          0       GIC  132  sata_rcar
> >  173:          0          0          0          0       GIC  173  gpio_rcar.0
> >  174:          0          0          0          0       GIC  174  gpio_rcar.1
> >  175:          0          0          0          0       GIC  175  gpio_rcar.2
> >  176:          0          0          0          0       GIC  176  gpio_rcar.3
> >  177:          0          0          0          0       GIC  177  gpio_rcar.4
> >  178:          0          0          0          0       GIC  178  gpio_rcar.5
> >  179:          0          0          0          0       GIC  179  gpio_rcar.6
> > 2001:          5          0          0          0  renesas_intc_irqpin.0    1  eth0
> > IPI0:          0          0          0          0  CPU wakeup interrupts
> > IPI1:          0          0          0          0  Timer broadcast interrupts
> > IPI2:        314        340         58         33  Rescheduling interrupts
> > IPI3:         22         56         34         56  Function call interrupts
> > IPI4:          0          0          0          0  Single function call interrupts
> > IPI5:          0          0          0          0  CPU stop interrupts
> >  Err:          0
> > ---
> >  arch/arm/mach-shmobile/setup-r8a7779.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/arm/mach-shmobile/setup-r8a7779.c b/arch/arm/mach-shmobile/setup-r8a7779.c
> > index ddee4aa..b0f56d6 100644
> > --- a/arch/arm/mach-shmobile/setup-r8a7779.c
> > +++ b/arch/arm/mach-shmobile/setup-r8a7779.c
> > @@ -597,8 +597,8 @@ void __init __weak r8a7779_register_twd(void) { }
> >  void __init r8a7779_earlytimer_init(void)
> >  {
> >         r8a7779_clock_init();
> > -       shmobile_earlytimer_init();
> >         r8a7779_register_twd();
> > +       shmobile_earlytimer_init();
> >  }
> >
> >  void __init r8a7779_add_early_devices(void)
> > --
> > 1.8.3.2
> >
> 
> Hi Simon,
> 
> Thanks for tracking down this issue. I think your patch looks fine to
> me.

Thanks, could I get an acked-by ?

> Regarding Marzen DT reference, I don't think TWD is used there yet
> so I doubt that it will have the same problem as the C version of the
> marzen board code.

Agreed.

> One related worry is that sh73a0 may have the same
> issue - or rather - judging by the code in sh73a0_earlytimer_init() it
> most certainly is affected by this too. So KZM9G should also fail as
> Marzen which means we need to fix sh73a0 too.

Curiously I do not seem to see the problem on the kzm9d.
Would you like me to prepare a patch anyway?