Re: [PATCH v6 4/7] ARM: l2c: Add support for overriding prefetch settings

From: Russell King - ARM Linux
Date: Tue Oct 28 2014 - 07:35:50 EST


On Mon, Oct 27, 2014 at 12:19:34PM +0100, Marek Szyprowski wrote:
> Hello,
>
> On 2014-10-27 12:14, Russell King - ARM Linux wrote:
>> On Mon, Oct 27, 2014 at 12:05:47PM +0100, Marek Szyprowski wrote:
>>> From: Tomasz Figa <t.figa@xxxxxxxxxxx>
>>>
>>> Firmware on certain boards (e.g. ODROID-U3) can leave incorrect L2C prefetch
>>> settings configured in registers leading to crashes if L2C is enabled
>>> without overriding them. This patch introduces bindings to enable
>>> prefetch settings to be specified from DT and necessary support in the
>>> driver.
>>>
>>> Signed-off-by: Tomasz Figa <t.figa@xxxxxxxxxxx>
>>> [mszyprow: rebased onto v3.18-rc1, added error messages when property value
>>> is missing]
>> Why? What if the boot loader has already set these up appropriately? Why
>> should we force people to list these in the DT?
>
> The error message is displayed only when user provided prefetch related
> properties without any value (empty properties). Something that Mark Rutland
> requested here: https://lkml.org/lkml/2014/9/24/426 I'm sorry if I didn't
> describe it clearly enough.

Ok.

I'd ask for one change. Please make all these messages start with
"L2C-310 OF" not "PL310 OF:". The device is described in ARM
documentation as a L2C-310 not PL310. (Also note the : is dropped
too - most of the other messages don't have the : either.)

The:

"PL310 OF: cache setting yield illegal associativity
PL310 OF: -1073346556 calculated, only 8 and 16 legal"

message could also be changed to something like:

"L2C-310 OF cache associativity %d invalid, only 8 or 16 permitted\n"

Thanks.

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