diff options
Diffstat (limited to 'drivers/iommu/of_iommu.c')
| -rw-r--r-- | drivers/iommu/of_iommu.c | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c index 5696314ae69e..522622e3f7df 100644 --- a/drivers/iommu/of_iommu.c +++ b/drivers/iommu/of_iommu.c @@ -11,6 +11,7 @@ #include <linux/module.h> #include <linux/msi.h> #include <linux/of.h> +#include <linux/of_address.h> #include <linux/of_iommu.h> #include <linux/of_pci.h> #include <linux/pci.h> @@ -172,3 +173,118 @@ const struct iommu_ops *of_iommu_configure(struct device *dev, return ops; } + +static inline bool check_direct_mapping(struct device *dev, struct resource *phys, + phys_addr_t start, phys_addr_t end) +{ + if (start != phys->start || end != phys->end) + return false; + + return true; +} + +static inline bool check_translated_mapping(struct device *dev, struct resource *phys, + phys_addr_t start, phys_addr_t end) +{ + if (end - start != phys->end - phys->start) { + dev_warn(dev, "treating non-overlapping mapping [%pr] -> [%pap-%pap] as reservation\n", + &phys, &start, &end); + return false; + } + + return true; +} + +/** + * of_iommu_get_resv_regions - reserved region driver helper for device tree + * @dev: device for which to get reserved regions + * @list: reserved region list + * + * IOMMU drivers can use this to implement their .get_resv_regions() callback + * for memory regions attached to a device tree node. See the reserved-memory + * device tree bindings on how to use these: + * + * Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt + */ +void of_iommu_get_resv_regions(struct device *dev, struct list_head *list) +{ +#if IS_ENABLED(CONFIG_OF_ADDRESS) + struct of_phandle_iterator it; + int err; + + of_for_each_phandle(&it, err, dev->of_node, "memory-region", NULL, 0) { + const __be32 *maps, *end; + struct resource res; + int size; + + memset(&res, 0, sizeof(res)); + + /* + * The "reg" property is optional and can be omitted by reserved-memory regions + * that represent reservations in the IOVA space, which are regions that should + * not be mapped. + */ + if (of_find_property(it.node, "reg", NULL)) { + err = of_address_to_resource(it.node, 0, &res); + if (err < 0) { + dev_err(dev, "failed to parse memory region %pOF: %d\n", + it.node, err); + continue; + } + } + + maps = of_get_property(it.node, "iommu-addresses", &size); + if (!maps) + continue; + + end = maps + size / sizeof(__be32); + + while (maps < end) { + struct device_node *np; + u32 phandle; + int na, ns; + + phandle = be32_to_cpup(maps++); + np = of_find_node_by_phandle(phandle); + na = of_n_addr_cells(np); + ns = of_n_size_cells(np); + + if (np == dev->of_node) { + int prot = IOMMU_READ | IOMMU_WRITE; + struct iommu_resv_region *region; + enum iommu_resv_type type; + phys_addr_t start; + size_t length; + + start = of_translate_dma_address(np, maps); + length = of_read_number(maps + na, ns); + + /* + * IOMMU regions without an associated physical region cannot be + * mapped and are simply reservations. + */ + if (res.end > res.start) { + phys_addr_t end = start + length - 1; + + if (check_direct_mapping(dev, &res, start, end)) + type = IOMMU_RESV_DIRECT_RELAXABLE; + else if (check_translated_mapping(dev, &res, start, end)) + type = IOMMU_RESV_TRANSLATED; + else + type = IOMMU_RESV_RESERVED; + } else { + type = IOMMU_RESV_RESERVED; + } + + region = iommu_alloc_resv_region_tr(res.start, start, length, prot, type, + GFP_KERNEL); + if (region) + list_add_tail(®ion->list, list); + } + + maps += na + ns; + } + } +#endif +} +EXPORT_SYMBOL(of_iommu_get_resv_regions); |