Re: [PATCH v18 1/5] iommu/arm-smmu: Add pm_runtime/sleep ops

[Thor Thayer <thor.thayer-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>]

On 11/27/18 4:11 AM, Vivek Gautam wrote:
> From: Sricharan R <sricharan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
> 
> The smmu needs to be functional only when the respective
> master's using it are active. The device_link feature
> helps to track such functional dependencies, so that the
> iommu gets powered when the master device enables itself
> using pm_runtime. So by adapting the smmu driver for
> runtime pm, above said dependency can be addressed.
> 
> This patch adds the pm runtime/sleep callbacks to the
> driver and also the functions to parse the smmu clocks
> from DT and enable them in resume/suspend.
> We pull all the information about clocks from device tree.
> 
> Also, while we enable the runtime pm add a pm sleep suspend
> callback that pushes devices to low power state by turning
> the clocks off in a system sleep.
> Also add corresponding clock enable path in resume callback.
> 
> Signed-off-by: Sricharan R <sricharan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
> Signed-off-by: Archit Taneja <architt-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
> [Thor: Rework to get clocks from device tree]
> Signed-off-by: Thor Thayer <thor.thayer-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> [vivek: rework for clock and pm ops]
> Signed-off-by: Vivek Gautam <vivek.gautam-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
> Reviewed-by: Tomasz Figa <tfiga-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
> Tested-by: Srinivas Kandagatla <srinivas.kandagatla-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> Reviewed-by: Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>
> ---
>   drivers/iommu/arm-smmu.c | 100 +++++++++++++++++++++++++++++++++++++++++++++--
>   1 file changed, 97 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index 5a28ae892504..e47c840fc6a8 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -44,10 +44,12 @@
>   #include <linux/module.h>
>   #include <linux/of.h>
>   #include <linux/of_address.h>
> +#include <linux/of_clk.h>
>   #include <linux/of_device.h>
>   #include <linux/of_iommu.h>
>   #include <linux/pci.h>
>   #include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
>   #include <linux/slab.h>
>   #include <linux/spinlock.h>
>  <snip>

Thanks! Tested the device tree clock portions on Intel SOCFPGA Stratix10 
DevKit.

Tested-by: Thor Thayer <thor.thayer-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>