[PATCH] ARM: prima2: remove L2 cache size override
Russell King - ARM Linux
linux at arm.linux.org.uk
Tue Apr 15 14:56:15 PDT 2014
On Tue, Apr 15, 2014 at 06:13:27PM +0800, Barry Song wrote:
> 2014-04-15 18:00 GMT+08:00 Russell King - ARM Linux <linux at arm.linux.org.uk>:
> > On Tue, Apr 15, 2014 at 05:49:02PM +0800, Barry Song wrote:
> >> From: Barry Song <Baohua.Song at csr.com>
> >> L2 cache size has been read by l2x0_init(), it is useless to set
> >> WAY_SIZE and ASSOCIATIVITY in prima2.
> >> Cc: Russell King <linux at arm.linux.org.uk>
> >> Signed-off-by: Barry Song <Baohua.Song at csr.com>
> >> ---
> >> -Derived from Russell's "ARM: l2c: prima2: remove cache size override"
> > You're a SMP architecture... it would be much better to initialise the
> > L2 cache before the secondary CPUs are brought online.
> ok, it seems we still need to hook this into the callback of this
> specific machine instead of using a global early_initcall(). since now
> the dt compatible field has been generic enough, it will cause other
> platforms to execute l2x0_of_init() too.
What I did for Versatile Express was to move it to the init_irq stage.
I'm not condoning using init_irq() for non-IRQ stuff, but that was
just to see whether it was possible (the .init_early is too early for
it.) Let me put it another way: I'm not thrilled by the idea of
having it in init_irq() but that's a better location to call L2 cache
initialisation than half-way through the kernel's initialisation.
> > In any case, across the board, it's preferable that the L2 cache is
> > enabled before the delay loop calibration as it can have an effect on
> > the calibrated value.
> what if the real case is that l2x0 has been enabled in bootloader?
If the L2 cache has already been enabled, l2x0_of_init() handles it -
in that situation, we can't re-do the enable (because writing to the
aux ctrl register is not allowed) so we merely setup the outer cache
function pointers and don't try to do any configuration or enabling.
FTTC broadband for 0.8mile line: now at 9.7Mbps down 460kbps up... slowly
improving, and getting towards what was expected from it.
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