Hi, a few comments On Fri, September 2, 2011 6:56 am, Marek Szyprowski wrote: ...
+struct dma_iommu_mapping {
- /* iommu specific data */
- struct iommu_domain *domain;
- void *bitmap;
In the earlier version of this patch you had this as a genpool instead of just doing the bitmaps manually. Is there a reason genpool can't be used to get the iova addresses?
- size_t bits;
- unsigned int order;
- dma_addr_t base;
- struct mutex lock;
+};
<snip>
+int arm_iommu_attach_device(struct device *dev, dma_addr_t base, size_t size, int order) +{
- unsigned int count = (size >> PAGE_SHIFT) - order;
- unsigned int bitmap_size = BITS_TO_LONGS(count) * sizeof(long);
- struct dma_iommu_mapping *mapping;
- int err = -ENOMEM;
- mapping = kzalloc(sizeof(struct dma_iommu_mapping), GFP_KERNEL);
- if (!mapping)
goto err;- mapping->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
- if (!mapping->bitmap)
goto err2;- mapping->base = base;
- mapping->bits = bitmap_size;
- mapping->order = order;
- mutex_init(&mapping->lock);
- mapping->domain = iommu_domain_alloc();
- if (!mapping->domain)
goto err3;- err = iommu_attach_device(mapping->domain, dev);
- if (err != 0)
goto err4;- dev->archdata.mapping = mapping;
- set_dma_ops(dev, &iommu_ops);
- printk(KERN_INFO "Attached IOMMU controller to %s device.\n",
dev_name(dev));
- return 0;
+err4:
- iommu_domain_free(mapping->domain);
+err3:
- kfree(mapping->bitmap);
+err2:
- kfree(mapping);
+err:
- return -ENOMEM;
+} +EXPORT_SYMBOL(arm_iommu_attach_device);
+#endif
Attach makes the assumption that each iommu device will exist in a separate domain. What if multiple devices want to use the same iommu domain? The msm iommu implementation has many different iommu devices but many of these will need the same buffer to be mapped in each context so currently many devices share the same domain. Without this, the same map call would need to happen for each device, which creates extra map calls and overhead.
Linaro-mm-sig mailing list Linaro-mm-sig@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-mm-sig
Laura