在 2007-09-04二的 12:03 +0200，Kevin D. Kissell写道：
> The 4KEc is a MIPS32 Release 2 processor, for which the implementation
> of the Cause.TI bit (bit 30) is required. You may have a defective board
> or a bad FPGA bitfile. Please work with your support contacts at MIPS
> to verify that this is not the case. It may also be that there's something
> more
> subtle going on in the interrupt processing, such that the Cause.TI bit is
> being
> cleared before it can be sampled by the code you've changed. But while the
> patch below presumably solves the symptoms of your problem, I really
> don't think that a kernel hack based on detecting CoreFPA3 is an appropriate
> solution. I work every day with Malta/CoreFPGA3 bitfiles and have not
> seen Cause.TI fail to function in any of the Release 2 core bitfiles I've
> used.
My board's core is Release 1 core. So Cause.TI bit always is zero. Maybe
I need update this patch to reflect this, i.e add #ifdef to distinguish
Release 1 and Release 2. Thanks.
Best Regards,
Yang Shi
>
> Regards,
>
> Kevin K.
>
> ----- Original Message -----
> From: "yshi" <yang.shi@windriver.com>
> To: <linux-mips@linux-mips.org>
> Sent: Tuesday, September 04, 2007 10:52 AM
> Subject: [PATCH] malta4kec hang in calibrate_delay fix
>
>
> > perfmon2 patch changed timer interrupt handler of malta board.
> > When kernel handles timer interrupt, interrupt handler will read 30 bit
> > of cause register. If this bit is zero, timer interrupt handler will
> > exit, won't really handle interrupt. Because Malta 4kec board's core
> > revision is CoreFPGA-3, this core's cause register doesn't implement 30
> > bit, so kernel always read zero from this bit. This will cause kernel
> > hang in calibrate_delay.
> >
> > Signed-off-by: Yang Shi <yang.shi@windriver.com>
> > ---
> > b/arch/mips/mips-boards/generic/time.c | 17 ++++++++++++-----
> > 1 file changed, 12 insertions(+), 5 deletions(-)
> > ---
> >
> > --- a/arch/mips/mips-boards/generic/time.c
> > +++ b/arch/mips/mips-boards/generic/time.c
> > @@ -136,11 +136,13 @@ irqreturn_t mips_timer_interrupt(int irq
> > #else /* CONFIG_MIPS_MT_SMTC */
> > int r2 = cpu_has_mips_r2;
> >
> > - if (handle_perf_irq(r2))
> > - goto out;
> > + if (mips_revision_corid != MIPS_REVISION_CORID_CORE_FPGA3) {
> > + if (handle_perf_irq(r2))
> > + goto out;
> >
> > - if (r2 && ((read_c0_cause() & (1 << 30)) == 0))
> > - goto out;
> > + if (r2 && ((read_c0_cause() & (1 << 30)) == 0))
> > + goto out;
> > + }
> >
> > if (cpu == 0) {
> > /*
> > @@ -294,7 +296,12 @@ void __init plat_timer_setup(struct irqa
> > {
> > if (cpu_has_vint)
> > set_vi_handler(cp0_compare_irq, mips_timer_dispatch);
> > - mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq;
> > +
> > + if (mips_revision_corid != MIPS_REVISION_CORID_CORE_FPGA3)
> > + mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE +
> > cp0_compare_irq;
> > + else
> > + mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE +
> > + CP0_LEGACY_COMPARE_IRQ;
> > }
> >
> > /* we are using the cpu counter for timer interrupts */
> >
> >
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