Re: [PATCH] DTS: DMA: Fix DMA3 interrupts
From: Hongbo Zhang
Date: Thu Dec 12 2013 - 04:46:43 EST
On 12/11/2013 02:33 AM, Scott Wood wrote:
On Tue, 2013-12-10 at 18:33 +0800, Hongbo Zhang wrote:
Scott,
This issue is due to the non-continuous MPIC register, I think there is
two ways to fix it.
The first one is as what we are discussing, in fact the Bman/Qman DT
author had introduced this way, and I had to follow it, it is a trick,
adding 208 is a bit ugly I think, and even difficult to explain it to
customers etc, but this way changes less codes.
The second one is editing MPIC related codes without adding 208 to high
interrupts. The point of translate interrupt number to MPIC register
address is a so called 'isu' mechanism, we can do like the following
example codes, then the tricky adding 208 isn't needed any more.
Which one do you prefer?
In fact I myself prefer the second, if the idea is acceptable, I will
send a patch instead of this one. (and also alone with the internal
patch decreasing 208 for the Bman/Qman)
void __init corenet_ds_pic_init(void)
{
......
mpic = mpic_alloc(NULL, 0, flags, 0, 512, "OpenPIC");
BUG_ON(mpic == NULL);
// Add this start
for (i = 0; i < 17; i++) {
if (i < 11)
addr_off = 0x10000 + 0x20 * 16 * i;
else
addr_off = 0x13000 + 0x20 * 16 * (i - 11); /* scape the
address not for interrupts */
mpic_assign_isu(mpic, i, mpic->paddr + addr_off);
}
// Add this end
mpic_init(mpic);
}
NACK
We already have a binding that states that the interrupt number is based
on the register offset, rather than whatever arbitrary numbers hardware
documenters decide to use next week.
While I'm not terribly happy with the usability of this, especially now
that it's not a simple "add 16", redefining the existing binding is not
OK (and in any case the code above seems obfuscatory). If we decide to
do something other than continue with register offset divided by 32,
then we need to define a new interrupt type (similar to current defined
types of error interrupt, timer, and IPI) for the new numberspace -- and
it should be handled when decoding that type of interrupt specifier,
rather than with the isu mechanism.
-Scott
Scott,
Thanks for your comments. Since the second way isn't so good, let's
choose the original one.
But we meet a small accident now.
My patch is based on the http://patchwork.ozlabs.org/patch/291553/,
which had been superseded, so this thread can be closed now.
And Shenzhou has already sent a complete dma3 dtsi patch including
correct interrupt numbers, http://patchwork.ozlabs.org/patch/300026/, so
let's focus on this patch, and I will forward your first comments of my
patch there.
Thanks.
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