Re: [PATCH v4 5/6] ARM: zynq: Add OCM controller driver

From: Michal Simek
Date: Mon Dec 01 2014 - 09:24:47 EST

On 11/28/2014 04:35 PM, Linus Walleij wrote:
> On Thu, Nov 27, 2014 at 2:57 PM, Michal Simek <michal.simek@xxxxxxxxxx> wrote:
>> On 11/27/2014 02:20 PM, Linus Walleij wrote:
>>> On Fri, Nov 14, 2014 at 11:52 AM, Michal Simek <michal.simek@xxxxxxxxxx> wrote:
>>> (...)
>>>> + zynq_ocmc->pool = devm_gen_pool_create(&pdev->dev,
>>>> + -1);
>>> Do this:
>>> #include <linux/sizes.h>
>>> zynq_ocmc->pool = devm_gen_pool_create(&pdev->dev,
>>> ilog2(SZ_64K),
>>> -1);
>>> And get rid of the #define for ZYNQ_OCMC_GRANULARITY
>> ilog2 from 32 is different to ilog2 from ilog2 from 0x10000.
> Bah I misread the code, forget this comment.
> Maybe it's more like I wanted
> +#define ZYNQ_OCMC_BLOCK_SIZE 0x10000
> To be replaced with SZ_64K
> But it's a petty detail anyway.

I have fixed it.

>> Do you have any opinion regarding calling zynq_slcr_get_ocm_config()?
>> Is it better to expose slcr this interface to drivers?
>> Or use regmap and read this value directly?
> Depends on what provides that call. The pattern I usually follow
> is to expose the mixed-registers range as a syscon device
> using drivers/mfd/syscon.c and then use one of the methods from
> <linux/mfd/syscon.h> to look up a reference to the regmap and
> use it to access misc registers.

I have tried it and I can just use it without any problem.
I have sent v5 with origin version but in cover letter there
is a code for that.

>> Also I do read for CONFIG_SMP case jump trampoline size - maybe
>> you can have better idea how this can be done.
> No I have no clue about that... :(

ok - fair enough. One option is to keep it as is. The second
option is to allocate any hardcoded size or size passed via DT.
But run-time detection is the best IMHO.


Michal Simek, Ing. (M.Eng), OpenPGP -> KeyID: FE3D1F91
w: p: +42-0-721842854
Maintainer of Linux kernel - Microblaze cpu -
Maintainer of Linux kernel - Xilinx Zynq ARM architecture
Microblaze U-BOOT custodian and responsible for u-boot arm zynq platform

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