An "IOMMU device" on the bus is poplulated first, "IOMMU'able devices" are done later. With CONFIG_OF_IOMMU, "#stream-id-cells" DT binding would be used to identify whether a device is IOMMU'able or not. If a device is IOMMU'able, we'll defer to populate that device till an iommu device is populated. Once an iommu device is populated, "dev->bus->iommu_ops" is set in the bus. Then, those defered IOMMU'able devices are populated and configured as IOMMU'abled with help of the already populated iommu device via iommu_ops->add_device(). Signed-off-by: Hiroshi Doyu <hdoyu@xxxxxxxxxx> --- Update: This is newly added, and the successor of the following RFC: [RFC][PATCHv3+ 1/2] driver/core: Add of_iommu_attach() http://lists.linuxfoundation.org/pipermail/iommu/2013-November/006914.html --- drivers/base/dd.c | 5 +++++ drivers/iommu/of_iommu.c | 33 +++++++++++++++++++++++++++++++++ include/linux/of_iommu.h | 7 +++++++ 3 files changed, 45 insertions(+) diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 35fa368..6e892d4 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -25,6 +25,7 @@ #include <linux/async.h> #include <linux/pm_runtime.h> #include <linux/pinctrl/devinfo.h> +#include <linux/of_iommu.h> #include "base.h" #include "power/power.h" @@ -273,6 +274,10 @@ static int really_probe(struct device *dev, struct device_driver *drv) dev->driver = drv; + ret = of_iommu_attach(dev); + if (ret) + goto probe_failed; + /* If using pinctrl, bind pins now before probing */ ret = pinctrl_bind_pins(dev); if (ret) diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c index ee249bc..335bf6a 100644 --- a/drivers/iommu/of_iommu.c +++ b/drivers/iommu/of_iommu.c @@ -20,6 +20,8 @@ #include <linux/export.h> #include <linux/limits.h> #include <linux/of.h> +#include <linux/device.h> +#include <linux/iommu.h> /** * of_get_dma_window - Parse *dma-window property and returns 0 if found. @@ -88,3 +90,34 @@ int of_get_dma_window(struct device_node *dn, const char *prefix, int index, return 0; } EXPORT_SYMBOL_GPL(of_get_dma_window); + +static bool of_is_iommuable(struct device *dev) +{ + size_t bytes; + const __be32 *prop; + const char *propname = "#stream-id-cells"; + + prop = of_get_property(dev->of_node, propname, &bytes); + if (!prop || !bytes) + return false; + + pr_debug("%s=%d %s\n", propname, bytes, dev_name(dev)); + return true; +} + +int of_iommu_attach(struct device *dev) +{ + struct iommu_ops *ops; + + if (!of_is_iommuable(dev)) + return 0; + + ops = dev->bus->iommu_ops; + if (!ops) + return -EPROBE_DEFER; + + if (ops->add_device) + return ops->add_device(dev); + + return 0; +} diff --git a/include/linux/of_iommu.h b/include/linux/of_iommu.h index 51a560f..3457489 100644 --- a/include/linux/of_iommu.h +++ b/include/linux/of_iommu.h @@ -7,6 +7,8 @@ extern int of_get_dma_window(struct device_node *dn, const char *prefix, int index, unsigned long *busno, dma_addr_t *addr, size_t *size); +extern int of_iommu_attach(struct device *dev); + #else static inline int of_get_dma_window(struct device_node *dn, const char *prefix, @@ -16,6 +18,11 @@ static inline int of_get_dma_window(struct device_node *dn, const char *prefix, return -EINVAL; } +static inline int of_iommu_attach(struct device *dev) +{ + return 0; +} + #endif /* CONFIG_OF_IOMMU */ #endif /* __OF_IOMMU_H */ -- 1.8.1.5 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
