Re: [PATCH v7 04/16] drivers: iommu: make of_iommu_set/get_ops() DT agnostic

From: Robin Murphy
Date: Wed Nov 09 2016 - 09:40:20 EST


On 09/11/16 14:19, Lorenzo Pieralisi wrote:
> The of_iommu_{set/get}_ops() API is used to associate a device
> tree node with a specific set of IOMMU operations. The same
> kernel interface is required on systems booting with ACPI, where
> devices are not associated with a device tree node, therefore
> the interface requires generalization.
>
> The struct device fwnode member represents the fwnode token
> associated with the device and the struct it points at is firmware
> specific; regardless, it is initialized on both ACPI and DT systems
> and makes an ideal candidate to use it to associate a set of IOMMU
> operations to a given device, through its struct device.fwnode member
> pointer.
>
> Convert the DT specific of_iommu_{set/get}_ops() interface to
> use struct device.fwnode as a look-up token, making the interface
> usable on ACPI systems.
>
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> Tested-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> Tested-by: Tomasz Nowicki <tn@xxxxxxxxxxxx>
> Cc: Will Deacon <will.deacon@xxxxxxx>
> Cc: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> Cc: Robin Murphy <robin.murphy@xxxxxxx>
> Cc: Joerg Roedel <joro@xxxxxxxxxx>
> ---
> drivers/iommu/iommu.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> drivers/iommu/of_iommu.c | 39 ---------------------------------------
> include/linux/iommu.h | 14 ++++++++++++++
> include/linux/of_iommu.h | 12 ++++++++++--
> 4 files changed, 66 insertions(+), 41 deletions(-)
>
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 9a2f196..5c97c01 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -1615,6 +1615,48 @@ int iommu_request_dm_for_dev(struct device *dev)
> return ret;
> }
>
> +struct iommu_fwentry {

:)

> + struct list_head list;
> + struct fwnode_handle *fwnode;
> + const struct iommu_ops *ops;
> +};
> +static LIST_HEAD(iommu_fwentry_list);
> +static DEFINE_SPINLOCK(iommu_fwentry_lock);
> +
> +void fwnode_iommu_set_ops(struct fwnode_handle *fwnode,
> + const struct iommu_ops *ops)
> +{
> + struct iommu_fwentry *iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
> +
> + if (WARN_ON(!iommu))
> + return;
> +
> + if (is_of_node(fwnode))

Nit: this check is actually redundant, since to_of_node() already does
the right thing and of_node_get() is NULL-safe - iommu_fwspec_init()
already works that way. On the other hand, though, it is perhaps more
intuitive to see it explicitly, and since to_of_node() is inline it
ought to result in the same object code (I've not checked, though).
Either way:

Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>

> + of_node_get(to_of_node(fwnode));
> +
> + INIT_LIST_HEAD(&iommu->list);
> + iommu->fwnode = fwnode;
> + iommu->ops = ops;
> + spin_lock(&iommu_fwentry_lock);
> + list_add_tail(&iommu->list, &iommu_fwentry_list);
> + spin_unlock(&iommu_fwentry_lock);
> +}
> +
> +const struct iommu_ops *fwnode_iommu_get_ops(struct fwnode_handle *fwnode)
> +{
> + struct iommu_fwentry *node;
> + const struct iommu_ops *ops = NULL;
> +
> + spin_lock(&iommu_fwentry_lock);
> + list_for_each_entry(node, &iommu_fwentry_list, list)
> + if (node->fwnode == fwnode) {
> + ops = node->ops;
> + break;
> + }
> + spin_unlock(&iommu_fwentry_lock);
> + return ops;
> +}
> +
> int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode,
> const struct iommu_ops *ops)
> {
> diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
> index 5b82862..0f57ddc 100644
> --- a/drivers/iommu/of_iommu.c
> +++ b/drivers/iommu/of_iommu.c
> @@ -96,45 +96,6 @@ int of_get_dma_window(struct device_node *dn, const char *prefix, int index,
> }
> EXPORT_SYMBOL_GPL(of_get_dma_window);
>
> -struct of_iommu_node {
> - struct list_head list;
> - struct device_node *np;
> - const struct iommu_ops *ops;
> -};
> -static LIST_HEAD(of_iommu_list);
> -static DEFINE_SPINLOCK(of_iommu_lock);
> -
> -void of_iommu_set_ops(struct device_node *np, const struct iommu_ops *ops)
> -{
> - struct of_iommu_node *iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
> -
> - if (WARN_ON(!iommu))
> - return;
> -
> - of_node_get(np);
> - INIT_LIST_HEAD(&iommu->list);
> - iommu->np = np;
> - iommu->ops = ops;
> - spin_lock(&of_iommu_lock);
> - list_add_tail(&iommu->list, &of_iommu_list);
> - spin_unlock(&of_iommu_lock);
> -}
> -
> -const struct iommu_ops *of_iommu_get_ops(struct device_node *np)
> -{
> - struct of_iommu_node *node;
> - const struct iommu_ops *ops = NULL;
> -
> - spin_lock(&of_iommu_lock);
> - list_for_each_entry(node, &of_iommu_list, list)
> - if (node->np == np) {
> - ops = node->ops;
> - break;
> - }
> - spin_unlock(&of_iommu_lock);
> - return ops;
> -}
> -
> static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data)
> {
> struct of_phandle_args *iommu_spec = data;
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index 436dc21..15d5478 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -351,6 +351,9 @@ int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode,
> const struct iommu_ops *ops);
> void iommu_fwspec_free(struct device *dev);
> int iommu_fwspec_add_ids(struct device *dev, u32 *ids, int num_ids);
> +void fwnode_iommu_set_ops(struct fwnode_handle *fwnode,
> + const struct iommu_ops *ops);
> +const struct iommu_ops *fwnode_iommu_get_ops(struct fwnode_handle *fwnode);
>
> #else /* CONFIG_IOMMU_API */
>
> @@ -580,6 +583,17 @@ static inline int iommu_fwspec_add_ids(struct device *dev, u32 *ids,
> return -ENODEV;
> }
>
> +static inline void fwnode_iommu_set_ops(struct fwnode_handle *fwnode,
> + const struct iommu_ops *ops)
> +{
> +}
> +
> +static inline
> +const struct iommu_ops *fwnode_iommu_get_ops(struct fwnode_handle *fwnode)
> +{
> + return NULL;
> +}
> +
> #endif /* CONFIG_IOMMU_API */
>
> #endif /* __LINUX_IOMMU_H */
> diff --git a/include/linux/of_iommu.h b/include/linux/of_iommu.h
> index e80b9c7..7681007 100644
> --- a/include/linux/of_iommu.h
> +++ b/include/linux/of_iommu.h
> @@ -31,8 +31,16 @@ static inline const struct iommu_ops *of_iommu_configure(struct device *dev,
>
> #endif /* CONFIG_OF_IOMMU */
>
> -void of_iommu_set_ops(struct device_node *np, const struct iommu_ops *ops);
> -const struct iommu_ops *of_iommu_get_ops(struct device_node *np);
> +static inline void of_iommu_set_ops(struct device_node *np,
> + const struct iommu_ops *ops)
> +{
> + fwnode_iommu_set_ops(&np->fwnode, ops);
> +}
> +
> +static inline const struct iommu_ops *of_iommu_get_ops(struct device_node *np)
> +{
> + return fwnode_iommu_get_ops(&np->fwnode);
> +}
>
> extern struct of_device_id __iommu_of_table;
>
>