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

Magnus Damm magnus.damm at gmail.com
Wed Aug 28 02:58:39 EDT 2013


Hi Simon,

On Thu, Aug 22, 2013 at 4:39 PM, Simon Horman <horms at verge.net.au> wrote:
> 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 ?

Yes, of course.

Acked-by: Magnus Damm <damm at opensource.se>

>> 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?

I meant kzm9g, not kzm9d. =)

I believe emev2 and kzm9d is most likely OK as-is. (except for the STI
broadcast issue that still is on my TODO)

However sh73a0 and kzm9g probably needs a similar fix as this patch.
When you have time, can you please check?

Thanks,

/ magnus



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