On Tue, Aug 23, 2016 at 08:05:22PM +0100, Robin Murphy wrote:
> To be able to support the generic bindings and handle of_xlate() calls,
> we need to be able to associate SMMUs and stream IDs directly with
> devices *before* allocating IOMMU groups. Furthermore, to support real
> default domains with multi-device groups we also have to handle domain
> attach on a per-device basis, as the "whole group at a time" assumption
> fails to properly handle subsequent devices added to a group after the
> first has already triggered default domain creation and attachment.
>
> To that end, use the now-vacant dev->archdata.iommu field for easy
> config and SMMU instance lookup, and unify config management by chopping
> down the platform-device-specific tree and probing the "mmu-masters"
> property on-demand instead. This may add a bit of one-off overhead to
> initially adding a new device, but we're about to deprecate that binding
> in favour of the inherently-more-efficient generic ones anyway.
>
> For the sake of simplicity, this patch does temporarily regress the case
> of aliasing PCI devices by losing the duplicate stream ID detection that
> the previous per-group config had. Stay tuned, because we'll be back to
> fix that in a better and more general way momentarily...
>
> Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
> ---
> drivers/iommu/arm-smmu.c | 382 +++++++++++++----------------------------------
> 1 file changed, 107 insertions(+), 275 deletions(-)
>
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index 22c093030322..9066fd1399d4 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -317,18 +317,13 @@ struct arm_smmu_smr {
> };
>
> struct arm_smmu_master_cfg {
> + struct arm_smmu_device *smmu;
> int num_streamids;
> u16 streamids[MAX_MASTER_STREAMIDS];
> s16 smendx[MAX_MASTER_STREAMIDS];
> };
> #define INVALID_SMENDX -1
>
> -struct arm_smmu_master {
> - struct device_node *of_node;
> - struct rb_node node;
> - struct arm_smmu_master_cfg cfg;
> -};
> -
> struct arm_smmu_device {
> struct device *dev;
>
> @@ -376,7 +371,6 @@ struct arm_smmu_device {
> unsigned int *irqs;
>
> struct list_head list;
> - struct rb_root masters;
>
> u32 cavium_id_base; /* Specific to Cavium */
> };
> @@ -415,12 +409,6 @@ struct arm_smmu_domain {
> struct iommu_domain domain;
> };
>
> -struct arm_smmu_phandle_args {
> - struct device_node *np;
> - int args_count;
> - uint32_t args[MAX_MASTER_STREAMIDS];
> -};
> -
> static DEFINE_SPINLOCK(arm_smmu_devices_lock);
> static LIST_HEAD(arm_smmu_devices);
>
> @@ -462,132 +450,89 @@ static struct device_node *dev_get_dev_node(struct device *dev)
>
> while (!pci_is_root_bus(bus))
> bus = bus->parent;
> - return bus->bridge->parent->of_node;
> + return of_node_get(bus->bridge->parent->of_node);
> }
>
> - return dev->of_node;
> + return of_node_get(dev->of_node);
> }
>
> -static struct arm_smmu_master *find_smmu_master(struct arm_smmu_device *smmu,
> - struct device_node *dev_node)
> +static int __arm_smmu_get_pci_sid(struct pci_dev *pdev, u16 alias, void *data)
> {
> - struct rb_node *node = smmu->masters.rb_node;
> -
> - while (node) {
> - struct arm_smmu_master *master;
> -
> - master = container_of(node, struct arm_smmu_master, node);
> -
> - if (dev_node < master->of_node)
> - node = node->rb_left;
> - else if (dev_node > master->of_node)
> - node = node->rb_right;
> - else
> - return master;
> - }
> -
> - return NULL;
> + *((__be32 *)data) = cpu_to_be32(alias);
> + return 0; /* Continue walking */
> }
>
> -static struct arm_smmu_master_cfg *
> -find_smmu_master_cfg(struct device *dev)
> +static int __find_legacy_master_phandle(struct device *dev, void *data)
> {
> - struct arm_smmu_master_cfg *cfg = NULL;
> - struct iommu_group *group = iommu_group_get(dev);
> + struct of_phandle_iterator *it = *(void **)data;
> + struct device_node *np = it->node;
> + int err;
>
> - if (group) {
> - cfg = iommu_group_get_iommudata(group);
> - iommu_group_put(group);
> - }
> -
> - return cfg;
> -}
> -
> -static int insert_smmu_master(struct arm_smmu_device *smmu,
> - struct arm_smmu_master *master)
> -{
> - struct rb_node **new, *parent;
> -
> - new = &smmu->masters.rb_node;
> - parent = NULL;
> - while (*new) {
> - struct arm_smmu_master *this
> - = container_of(*new, struct arm_smmu_master, node);
> -
> - parent = *new;
> - if (master->of_node < this->of_node)
> - new = &((*new)->rb_left);
> - else if (master->of_node > this->of_node)
> - new = &((*new)->rb_right);
> - else
> - return -EEXIST;
> - }
> -
> - rb_link_node(&master->node, parent, new);
> - rb_insert_color(&master->node, &smmu->masters);
> - return 0;
> -}
> -
> -static int register_smmu_master(struct arm_smmu_device *smmu,
> - struct device *dev,
> - struct arm_smmu_phandle_args *masterspec)
> -{
> - int i;
> - struct arm_smmu_master *master;
> -
> - master = find_smmu_master(smmu, masterspec->np);
> - if (master) {
> - dev_err(dev,
> - "rejecting multiple registrations for master device %s\n",
> - masterspec->np->name);
> - return -EBUSY;
> - }
> -
> - if (masterspec->args_count > MAX_MASTER_STREAMIDS) {
> - dev_err(dev,
> - "reached maximum number (%d) of stream IDs for master device %s\n",
> - MAX_MASTER_STREAMIDS, masterspec->np->name);
> - return -ENOSPC;
> - }
> -
> - master = devm_kzalloc(dev, sizeof(*master), GFP_KERNEL);
> - if (!master)
> - return -ENOMEM;
> -
> - master->of_node = masterspec->np;
> - master->cfg.num_streamids = masterspec->args_count;
> -
> - for (i = 0; i < master->cfg.num_streamids; ++i) {
> - u16 streamid = masterspec->args[i];
> -
> - if (!(smmu->features & ARM_SMMU_FEAT_STREAM_MATCH) &&
> - (streamid >= smmu->num_mapping_groups)) {
> - dev_err(dev,
> - "stream ID for master device %s greater than maximum allowed (%d)\n",
> - masterspec->np->name, smmu->num_mapping_groups);
> - return -ERANGE;
> + of_for_each_phandle(it, err, dev->of_node, "mmu-masters",
> + "#stream-id-cells", 0)
> + if (it->node == np) {
> + *(void **)data = dev;
> + return 1;
> }
> - master->cfg.streamids[i] = streamid;
> - master->cfg.smendx[i] = INVALID_SMENDX;
> - }
> - return insert_smmu_master(smmu, master);
> + it->node = np;
> + return err;
> }
>
> -static struct arm_smmu_device *find_smmu_for_device(struct device *dev)
> +static int arm_smmu_register_legacy_master(struct device *dev)
> {
> struct arm_smmu_device *smmu;
> - struct arm_smmu_master *master = NULL;
> - struct device_node *dev_node = dev_get_dev_node(dev);
> + struct arm_smmu_master_cfg *cfg;
> + struct device_node *np;
> + struct of_phandle_iterator it;
> + void *data = ⁢
> + __be32 pci_sid;
> + int err;
>
> + np = dev_get_dev_node(dev);
> + if (!np || !of_find_property(np, "#stream-id-cells", NULL)) {
> + of_node_put(np);
> + return -ENODEV;
> + }
> +
> + it.node = np;
> spin_lock(&arm_smmu_devices_lock);
> list_for_each_entry(smmu, &arm_smmu_devices, list) {
> - master = find_smmu_master(smmu, dev_node);
> - if (master)
> + err = __find_legacy_master_phandle(smmu->dev, &data);
> + if (err)
> break;
> }
> spin_unlock(&arm_smmu_devices_lock);
> + of_node_put(np);
> + if (err == 0)
> + return -ENODEV;
> + if (err < 0)
> + return err;
>
> - return master ? smmu : NULL;
> + if (it.cur_count > MAX_MASTER_STREAMIDS) {
> + dev_err(smmu->dev,
> + "reached maximum number (%d) of stream IDs for master device %s\n",
> + MAX_MASTER_STREAMIDS, dev_name(dev));
> + return -ENOSPC;
> + }
> + if (dev_is_pci(dev)) {
> + /* "mmu-masters" assumes Stream ID == Requester ID */
> + pci_for_each_dma_alias(to_pci_dev(dev), __arm_smmu_get_pci_sid,
> + &pci_sid);
> + it.cur = &pci_sid;
> + it.cur_count = 1;
> + }
> +
> + cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
> + if (!cfg)
> + return -ENOMEM;
> +
> + cfg->smmu = smmu;
> + dev->archdata.iommu = cfg;
> +
> + while (it.cur_count--)
> + cfg->streamids[cfg->num_streamids++] = be32_to_cpup(it.cur++);
I pronounce this construct, the "Murphy Device"! At least it didn't survive
until the end of the series :p
Will
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