Hello Marc,
On 2024-12-23 00:16, Marc Zyngier wrote:
On Sun, 22 Dec 2024 18:25:02 +0000,
Dragan Simic <dsimic@xxxxxxxxxxx> wrote:
On 2024-12-22 10:04, Marc Zyngier wrote:
> On Sun, 22 Dec 2024 03:03:53 +0000,
> FUKAUMI Naoki <naoki@xxxxxxxxx> wrote:
>>
>> Rockchip RK3582 is a scaled down version of Rockchip RK3588(S). Apply
>> Rockchip 3588001 erratum workaround to RK3582.
>>
>> Signed-off-by: FUKAUMI Naoki <naoki@xxxxxxxxx>
>> ---
>> drivers/irqchip/irq-gic-v3-its.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/irqchip/irq-gic-v3-its.c
>> b/drivers/irqchip/irq-gic-v3-its.c
>> index 92244cfa0464..c59ce9332dc0 100644
>> --- a/drivers/irqchip/irq-gic-v3-its.c
>> +++ b/drivers/irqchip/irq-gic-v3-its.c
>> @@ -4861,7 +4861,8 @@ static bool __maybe_unused
>> its_enable_rk3588001(void *data)
>> {
>> struct its_node *its = data;
>>
>> - if (!of_machine_is_compatible("rockchip,rk3588") &&
>> + if (!of_machine_is_compatible("rockchip,rk3582") &&
>> + !of_machine_is_compatible("rockchip,rk3588") &&
>> !of_machine_is_compatible("rockchip,rk3588s"))
>> return false;
>>
>
> Please use the relevant property for that purpose ("dma-noncoherent")
> at the distributor and ITS levels. We're not adding extra compatibles
> for this anymore, and you might as well fix the core dtsi to expose
> such property.
Thanks for your response.
After a more detailed look into drivers/irqchip/irq-gic-v3-its.c,
it seems that relying on the "dma-noncoherent" DT property may not
be equivalent to adding another compatible check.
It is. My email makes it plain what needs doing.
Here are a few
quotations from irq-gic-v3-its.c, to illustrate this better:
4746 static bool __maybe_unused its_enable_rk3588001(void *data)
4747 {
4748 struct its_node *its = data;
4749
4750 if (!of_machine_is_compatible("rockchip,rk3588") &&
4751 !of_machine_is_compatible("rockchip,rk3588s"))
4752 return false;
4753
4754 its->flags |= ITS_FLAGS_FORCE_NON_SHAREABLE;
4755 gic_rdists->flags |= RDIST_FLAGS_FORCE_NON_SHAREABLE;
4756
4757 return true;
4758 }
4759
4760 static bool its_set_non_coherent(void *data)
4761 {
4762 struct its_node *its = data;
4763
4764 its->flags |= ITS_FLAGS_FORCE_NON_SHAREABLE;
4765 return true;
4766 }
4814 #ifdef CONFIG_ROCKCHIP_ERRATUM_3588001
4815 {
4816 .desc = "ITS: Rockchip erratum RK3588001",
4817 .iidr = 0x0201743b,
4818 .mask = 0xffffffff,
4819 .init = its_enable_rk3588001,
4820 },
4821 #endif
4822 {
4823 .desc = "ITS: non-coherent attribute",
4824 .property = "dma-noncoherent",
4825 .init = its_set_non_coherent,
4826 },
Nothing tickles me more than having my own work being thrown back at
me.
I'm sorry, that wasn't my intention. I just wanted to make
referencing to what I was talking about a bit easier. Though,
I now see that I was wrong, and I apologize for the noise.
As visible above, using the "dma-noncoherent" DT property results
in not setting the RDIST_FLAGS_FORCE_NON_SHAREABLE flag, which the
its_enable_rk3588001() function does. In other words, it doesn't
seem that "dma-noncoherent" is a "drop-in" replacement for adding
yet another compatible for the RK3582.
You clearly haven't read what I wrote. Or rather, you read what you
wanted to read, and ignored half of it.
No, it an honest mistake, nothing else. My intention is never to
twist the reality in any way.
Modifying the current behavior of the "dma-noncoherent" DT property
doesn't seem like an option, because it's already used in a couple
of board dts(i) files. Should we introduce another DT property,
perhaps "dma-noncoherent-rdist" or something similar?
No. We have everything we need. Believe it or not, I actually know
what I'm talking about. I know, this is surprising. I surprise myself
sometimes.
It wasn't my intention to insult you in any way. I highly respect
everyone's work, including yours, of course. I am a human being,
so perhaps I am allowed to be tired a bit and, as a result, make
an honest mistake from time to time?
Could you, please, advise on how to move forward with this? I'm
I already have.
Yes, I see it now. I'm sorry for not reading the code more carefully
the first time. I read your earlier response carefully, but I missed
to read the code carefully as well.
willing to implement the required patches, but I'd prefer to reduce
the possible back-and-forth on them, to save everyone's time.
May I suggest that you read my email again? How about grepping through
the upstream DT collection and (shock, horror) look at the imx95.dtsi
file, which suffers from the same braindead behaviour as the RK stuff?
For clarity, let me paste it here again, and add some emphasis for
extra clarity:
> Please use the relevant property for that purpose ("dma-noncoherent")
> at the distributor and ITS levels. We're not adding extra compatibles
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Now, please go look at the code for real this time, appreciate how the
"dma-noncoherent" property placed at the distributor *AND* ITS levels
combine to give you the effects the hardware requires.
You're absolutely right, and I should've read the code more carefully.
I stand corrected, and I appreciate your additional explanation.
To sum it up: the standard properties and the Rockchip hacks are
strictly equivalent, there is no need for anything extra, and I stand
by my NAK on this very patch.
Please note that I never questioned that this patch shouldn't be
dropped.
I just missed some parts of the code, as an honest mistake, for which I
apologize once again.
