We set the internal iommu_sw pointer to the passed in swiotlb_engine
structure. Obviously we also check if the existing iommu_sw is
set and if so, call iommu_sw->release before the switch-over.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
include/linux/swiotlb.h | 2 +
lib/swiotlb.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 50 insertions(+), 0 deletions(-)
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 781c3aa..3bc3c42 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -118,6 +118,8 @@ struct swiotlb_engine {
void* (*bus_to_virt)(struct device *hwdev, dma_addr_t address);
};
+int swiotlb_register_engine(struct swiotlb_engine *iommu);
+
extern void
*swiotlb_alloc_coherent(struct device *hwdev, size_t size,
dma_addr_t *dma_handle, gfp_t flags);
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index e6d9e32..e84f269 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -97,6 +97,12 @@ static phys_addr_t *io_tlb_orig_addr;
*/
static DEFINE_SPINLOCK(io_tlb_lock);
+/*
+ * The software IOMMU this library will utilize.
+ */
+struct swiotlb_engine *iommu_sw;
+EXPORT_SYMBOL(iommu_sw);
+
static int late_alloc;
static int __init
@@ -126,6 +132,48 @@ static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev,
return phys_to_dma(hwdev, virt_to_phys(address));
}
+/*
+ * Register a software IO TLB engine.
+ *
+ * The registration allows the software IO TLB functions in the
+ * swiotlb library to function properly.
+ *
+ * All the values in the iotlb structure must be set.
+ *
+ * If the registration fails, it is assumed that the caller will free
+ * all of the resources allocated in the swiotlb_engine structure.
+ */
+int swiotlb_register_engine(struct swiotlb_engine *iommu)
+{
+ if (!iommu || !iommu->name || !iommu->release) {
+ printk(KERN_ERR "DMA: Trying to register a SWIOTLB engine" \
+ " improperly!");
+ return -EINVAL;
+ }
+
+ if (iommu_sw && iommu_sw->name) {
+ int retval = -EINVAL;
+
+ /* 'release' must check for out-standing DMAs and flush them
+ * out or fail. */
+ if (iommu_sw->release)
+ retval = iommu_sw->release(iommu_sw);
+
+ if (retval) {
+ printk(KERN_ERR "DMA: %s cannot be released!\n",
+ iommu_sw->name);
+ return retval;
+ }
+ printk(KERN_INFO "DMA: Replacing [%s] with [%s]\n",
+ iommu_sw->name, iommu->name);
+ }
+
+ iommu_sw = iommu;
+
+ return 0;
+}
+EXPORT_SYMBOL(swiotlb_register_engine);
+
void swiotlb_print_info(void)
{
unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT;
--
1.6.2.5
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