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Subject[PATCH v4 06/14] swiotlb: Add restricted DMA pool
Date
Add the initialization function to create restricted DMA pools from
matching reserved-memory nodes.

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
include/linux/device.h | 4 ++
kernel/dma/swiotlb.c | 94 +++++++++++++++++++++++++++++++++++++++++-
2 files changed, 97 insertions(+), 1 deletion(-)

diff --git a/include/linux/device.h b/include/linux/device.h
index 7619a84f8ce4..08d440627b93 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -415,6 +415,7 @@ struct dev_links_info {
* @dma_pools: Dma pools (if dma'ble device).
* @dma_mem: Internal for coherent mem override.
* @cma_area: Contiguous memory area for dma allocations
+ * @dev_swiotlb: Internal for swiotlb override.
* @archdata: For arch-specific additions.
* @of_node: Associated device tree node.
* @fwnode: Associated device node supplied by platform firmware.
@@ -517,6 +518,9 @@ struct device {
#ifdef CONFIG_DMA_CMA
struct cma *cma_area; /* contiguous memory area for dma
allocations */
+#endif
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+ struct swiotlb *dev_swiotlb;
#endif
/* arch specific additions */
struct dev_archdata archdata;
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index dc37951c6924..3a17451c5981 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -39,6 +39,13 @@
#ifdef CONFIG_DEBUG_FS
#include <linux/debugfs.h>
#endif
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/of_reserved_mem.h>
+#include <linux/slab.h>
+#endif

#include <asm/io.h>
#include <asm/dma.h>
@@ -75,7 +82,8 @@ enum swiotlb_force swiotlb_force;
* range check to see if the memory was in fact allocated by this
* API.
* @nslabs: The number of IO TLB blocks (in groups of 64) between @start and
- * @end. This is command line adjustable via setup_io_tlb_npages.
+ * @end. For default swiotlb, this is command line adjustable via
+ * setup_io_tlb_npages.
* @used: The number of used IO TLB block.
* @list: The free list describing the number of free entries available
* from each index.
@@ -780,3 +788,87 @@ static int __init swiotlb_create_default_debugfs(void)

late_initcall(swiotlb_create_default_debugfs);
#endif
+
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+static int rmem_swiotlb_device_init(struct reserved_mem *rmem,
+ struct device *dev)
+{
+ struct swiotlb *swiotlb = rmem->priv;
+ int ret;
+
+ if (dev->dev_swiotlb)
+ return -EBUSY;
+
+ /* Since multiple devices can share the same pool, the private data,
+ * swiotlb struct, will be initialized by the first device attached
+ * to it.
+ */
+ if (!swiotlb) {
+ swiotlb = kzalloc(sizeof(*swiotlb), GFP_KERNEL);
+ if (!swiotlb)
+ return -ENOMEM;
+#ifdef CONFIG_ARM
+ unsigned long pfn = PHYS_PFN(reme->base);
+
+ if (!PageHighMem(pfn_to_page(pfn))) {
+ ret = -EINVAL;
+ goto cleanup;
+ }
+#endif /* CONFIG_ARM */
+
+ ret = swiotlb_init_tlb_pool(swiotlb, rmem->base, rmem->size);
+ if (ret)
+ goto cleanup;
+
+ rmem->priv = swiotlb;
+ }
+
+#ifdef CONFIG_DEBUG_FS
+ swiotlb_create_debugfs(swiotlb, rmem->name, default_swiotlb.debugfs);
+#endif /* CONFIG_DEBUG_FS */
+
+ dev->dev_swiotlb = swiotlb;
+
+ return 0;
+
+cleanup:
+ kfree(swiotlb);
+
+ return ret;
+}
+
+static void rmem_swiotlb_device_release(struct reserved_mem *rmem,
+ struct device *dev)
+{
+ if (!dev)
+ return;
+
+#ifdef CONFIG_DEBUG_FS
+ debugfs_remove_recursive(dev->dev_swiotlb->debugfs);
+#endif /* CONFIG_DEBUG_FS */
+ dev->dev_swiotlb = NULL;
+}
+
+static const struct reserved_mem_ops rmem_swiotlb_ops = {
+ .device_init = rmem_swiotlb_device_init,
+ .device_release = rmem_swiotlb_device_release,
+};
+
+static int __init rmem_swiotlb_setup(struct reserved_mem *rmem)
+{
+ unsigned long node = rmem->fdt_node;
+
+ if (of_get_flat_dt_prop(node, "reusable", NULL) ||
+ of_get_flat_dt_prop(node, "linux,cma-default", NULL) ||
+ of_get_flat_dt_prop(node, "linux,dma-default", NULL) ||
+ of_get_flat_dt_prop(node, "no-map", NULL))
+ return -EINVAL;
+
+ rmem->ops = &rmem_swiotlb_ops;
+ pr_info("Reserved memory: created device swiotlb memory pool at %pa, size %ld MiB\n",
+ &rmem->base, (unsigned long)rmem->size / SZ_1M);
+ return 0;
+}
+
+RESERVEDMEM_OF_DECLARE(dma, "restricted-dma-pool", rmem_swiotlb_setup);
+#endif /* CONFIG_DMA_RESTRICTED_POOL */
--
2.30.0.478.g8a0d178c01-goog
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