Re: [PATCHv3 2/2] iommu/arm-smmu: Add SMMU clock

[Thor Thayer]

Hi Vivek,

On 10/04/2018 01:49 PM, Vivek Gautam wrote:
> Hi Thor,
>
>
> On 10/4/2018 3:58 AM, thor.thayer@xxxxxxxxxxxxxxx wrote:
> > From: Thor Thayer <thor.thayer@xxxxxxxxxxxxxxx>
> >
> > Add a clock to the SMMU structure. In the device tree case,
> > check for a clock node and enable the clock if found.
> >
> > This patch is dependent upon the following patches that add
> > a device tree bulk clock function.
> > "[V6, 1/4] clk: bulk: add of_clk_bulk_get()"
> > https://patchwork.kernel.org/patch/10583133/
> > "[V6, 2/4] clk: add new APIs to operation on all available
> > clocks"
> > https://patchwork.kernel.org/patch/10583131/
> > "[V6, 3/4] clk: add managed version of clk_bulk_get_all"
> > https://patchwork.kernel.org/patch/10583139/
> >
> > Signed-off-by: Thor Thayer <thor.thayer@xxxxxxxxxxxxxxx>
> > ---
> > Â drivers/iommu/arm-smmu.c | 20 ++++++++++++++++++++
> > Â 1 file changed, 20 insertions(+)
>
> The clock part is already handled by one of the patch in the
> runtime pm series of arm-smmu [1]. This patch should not be needed.
>
> [1] https://patchwork.kernel.org/patch/10581899/
>
> [...]
>
> Regards
> Vivek

Thanks. FYI, I had problems applying [v16,2/5] on [1] but was able to 
apply [v17,2/5] cleanly.

The bigger issue is that with your patchset I need to create a new 
structure for my variation of the ARM SMMUv2 due to the 
of_device_get_match_data() call in arm_smmu_device_dt_probe(). I want to 
use the default arm_mmu500 but it doesn't have a clock specified and I 
end up with num_clks of 0.

Creating a new smmu_match_data structure for each variant feels wrong 
because I have the clock data specified in my device tree. The 
of_clk_bulk_get() call handles this nicely but that patchset isn't 
getting much attention.

I'll investigate adding the of_clk_bulk_get() call on top of your 
patches. This may simplify your patches too since the additional 
structures in [v16,5/5] wouldn't be needed.

Thanks,

Thor

[1] git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git - next