Re: [PATCHv3 14/19] iommu/tegra: smmu: Get "nvidia,memory-clients" from DT

[Grant Likely <grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>]

On Fri, 18 Oct 2013 13:26:55 +0300, Hiroshi Doyu <hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> wrote:
> This provides the info about which swgroups a device belongs to. This
> info is passed from DT. This is necessary for the unified SMMU driver
> among Tegra SoCs since each has different H/W accelerators.
> 
> Signed-off-by: Hiroshi Doyu <hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> ---
>  .../bindings/iommu/nvidia,tegra30-smmu.txt         | 16 ++++++++++++-
>  drivers/iommu/tegra-smmu.c                         | 27 ++++++++++++++++++++--
>  2 files changed, 40 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/iommu/nvidia,tegra30-smmu.txt b/Documentation/devicetree/bindings/iommu/nvidia,tegra30-smmu.txt
> index 6a844b3..7456104 100644
> --- a/Documentation/devicetree/bindings/iommu/nvidia,tegra30-smmu.txt
> +++ b/Documentation/devicetree/bindings/iommu/nvidia,tegra30-smmu.txt
> @@ -13,9 +13,12 @@ Required properties:
>    file <dt-bindings/memory/tegra-swgroup.h>. Its max is 64. 2 cells
>    are required. This unique ID info can be used to calculate
>    MC_SMMU_<SWGROUP name>_ASID_0 offset and HOTRESET bit.
> +- nvidia,memory-clients: phandle to a smmu device which a device is
> +  attached to and indicates which swgroups a device belongs to(SWGROUP ID).
> +  SWGROUP ID is from 0 to 63, and a device can belong to multiple SWGROUPS.
>  
>  Example:
> -	smmu {
> +	smmu: iommu {
>  		compatible = "nvidia,tegra30-smmu";
>  		reg = <0x7000f010 0x02c
>  		       0x7000f1f0 0x010
> @@ -25,3 +28,14 @@ Example:
>  		nvidia,swgroups = <0x00000000 0x000779ff>;
>  		nvidia,ahb = <&ahb>;
>  	};
> +
> +	host1x {
> +		compatible = "nvidia,tegra30-host1x", "simple-bus";
> +		nvidia,memory-clients = <&smmu TEGRA_SWGROUP_HC>;
> +		....
> +		gr3d {
> +			compatible = "nvidia,tegra30-gr3d";
> +			nvidia,memory-clients = <&smmu TEGRA_SWGROUP_NV
> +						       TEGRA_SWGROUP_NV2>;
> +			....
> +		};
> diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
> index f0ff48e..1db9e89 100644
> --- a/drivers/iommu/tegra-smmu.c
> +++ b/drivers/iommu/tegra-smmu.c
> @@ -368,6 +368,29 @@ static inline void smmu_write(struct smmu_device *smmu, u32 val, size_t offs)
>  
>  #define smmu_client_hwgrp(c)	(c->as->smmu->swgroups)
>  
> +static u64 smmu_of_get_memory_client(struct device *dev)
> +{
> +	size_t bytes;
> +	const char *propname = "nvidia,memory-clients";
> +	const __be32 *prop;
> +	int i;
> +	u64 swgroup = 0;
> +	struct device_node *np;
> +
> +	np = of_parse_phandle(dev->of_node, propname, 0);
> +	if (np != smmu_handle->dev->of_node)
> +		return ~0;
> +
> +	prop = of_get_property(dev->of_node, propname, &bytes);
> +	if (!prop || !bytes)
> +		return ~0;
> +
> +	for (i = 1; i < bytes / sizeof(u32); i++, prop++)
> +		swgroup |= 1ULL << be32_to_cpup(prop);
> +
> +	return swgroup;
> +}
> +
>  static int __smmu_client_set_hwgrp(struct smmu_client *c,
>  				   u64 map, int on)
>  {
> @@ -779,8 +802,8 @@ static int smmu_iommu_attach_dev(struct iommu_domain *domain,
>  		return -ENOMEM;
>  	client->dev = dev;
>  	client->as = as;
> -	map = smmu->swgroups;
> -	if (!map)
> +	map = smmu_of_get_memory_client(dev);
> +	if (map == ~0)
>  		return -EINVAL;

Ditto to my previous comment. Can you return the currently used value if
the property isn't present? (it's okay to warn at the same time, but it
is best to avoid breakage).

g.