1 files changed, 463 insertions, 0 deletions
diff --git a/drivers/fpga/dfl-afu-dma-region.c b/drivers/fpga/dfl-afu-dma-region.c
new file mode 100644
index 000000000000..0e81d33af856
--- /dev/null
+++ b/drivers/fpga/dfl-afu-dma-region.c
@@ -0,0 +1,463 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for FPGA Accelerated Function Unit (AFU) DMA Region Management
+ *
+ * Copyright (C) 2017-2018 Intel Corporation, Inc.
+ *
+ * Authors:
+ *   Wu Hao <hao.wu@intel.com>
+ *   Xiao Guangrong <guangrong.xiao@linux.intel.com>
+ */
+
+#include <linux/dma-mapping.h>
+#include <linux/sched/signal.h>
+#include <linux/uaccess.h>
+
+#include "dfl-afu.h"
+
+static void put_all_pages(struct page **pages, int npages)
+{
+	int i;
+
+	for (i = 0; i < npages; i++)
+		if (pages[i])
+			put_page(pages[i]);
+}
+
+void afu_dma_region_init(struct dfl_feature_platform_data *pdata)
+{
+	struct dfl_afu *afu = dfl_fpga_pdata_get_private(pdata);
+
+	afu->dma_regions = RB_ROOT;
+}
+
+/**
+ * afu_dma_adjust_locked_vm - adjust locked memory
+ * @dev: port device
+ * @npages: number of pages
+ * @incr: increase or decrease locked memory
+ *
+ * Increase or decrease the locked memory size with npages input.
+ *
+ * Return 0 on success.
+ * Return -ENOMEM if locked memory size is over the limit and no CAP_IPC_LOCK.
+ */
+static int afu_dma_adjust_locked_vm(struct device *dev, long npages, bool incr)
+{
+	unsigned long locked, lock_limit;
+	int ret = 0;
+
+	/* the task is exiting. */
+	if (!current->mm)
+		return 0;
+
+	down_write(&current->mm->mmap_sem);
+
+	if (incr) {
+		locked = current->mm->locked_vm + npages;
+		lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
+
+		if (locked > lock_limit && !capable(CAP_IPC_LOCK))
+			ret = -ENOMEM;
+		else
+			current->mm->locked_vm += npages;
+	} else {
+		if (WARN_ON_ONCE(npages > current->mm->locked_vm))
+			npages = current->mm->locked_vm;
+		current->mm->locked_vm -= npages;
+	}
+
+	dev_dbg(dev, "[%d] RLIMIT_MEMLOCK %c%ld %ld/%ld%s\n", current->pid,
+		incr ? '+' : '-', npages << PAGE_SHIFT,
+		current->mm->locked_vm << PAGE_SHIFT, rlimit(RLIMIT_MEMLOCK),
+		ret ? "- execeeded" : "");
+
+	up_write(&current->mm->mmap_sem);
+
+	return ret;
+}
+
+/**
+ * afu_dma_pin_pages - pin pages of given dma memory region
+ * @pdata: feature device platform data
+ * @region: dma memory region to be pinned
+ *
+ * Pin all the pages of given dfl_afu_dma_region.
+ * Return 0 for success or negative error code.
+ */
+static int afu_dma_pin_pages(struct dfl_feature_platform_data *pdata,
+			     struct dfl_afu_dma_region *region)
+{
+	int npages = region->length >> PAGE_SHIFT;
+	struct device *dev = &pdata->dev->dev;
+	int ret, pinned;
+
+	ret = afu_dma_adjust_locked_vm(dev, npages, true);
+	if (ret)
+		return ret;
+
+	region->pages = kcalloc(npages, sizeof(struct page *), GFP_KERNEL);
+	if (!region->pages) {
+		ret = -ENOMEM;
+		goto unlock_vm;
+	}
+
+	pinned = get_user_pages_fast(region->user_addr, npages, 1,
+				     region->pages);
+	if (pinned < 0) {
+		ret = pinned;
+		goto put_pages;
+	} else if (pinned != npages) {
+		ret = -EFAULT;
+		goto free_pages;
+	}
+
+	dev_dbg(dev, "%d pages pinned\n", pinned);
+
+	return 0;
+
+put_pages:
+	put_all_pages(region->pages, pinned);
+free_pages:
+	kfree(region->pages);
+unlock_vm:
+	afu_dma_adjust_locked_vm(dev, npages, false);
+	return ret;
+}
+
+/**
+ * afu_dma_unpin_pages - unpin pages of given dma memory region
+ * @pdata: feature device platform data
+ * @region: dma memory region to be unpinned
+ *
+ * Unpin all the pages of given dfl_afu_dma_region.
+ * Return 0 for success or negative error code.
+ */
+static void afu_dma_unpin_pages(struct dfl_feature_platform_data *pdata,
+				struct dfl_afu_dma_region *region)
+{
+	long npages = region->length >> PAGE_SHIFT;
+	struct device *dev = &pdata->dev->dev;
+
+	put_all_pages(region->pages, npages);
+	kfree(region->pages);
+	afu_dma_adjust_locked_vm(dev, npages, false);
+
+	dev_dbg(dev, "%ld pages unpinned\n", npages);
+}
+
+/**
+ * afu_dma_check_continuous_pages - check if pages are continuous
+ * @region: dma memory region
+ *
+ * Return true if pages of given dma memory region have continuous physical
+ * address, otherwise return false.
+ */
+static bool afu_dma_check_continuous_pages(struct dfl_afu_dma_region *region)
+{
+	int npages = region->length >> PAGE_SHIFT;
+	int i;
+
+	for (i = 0; i < npages - 1; i++)
+		if (page_to_pfn(region->pages[i]) + 1 !=
+				page_to_pfn(region->pages[i + 1]))
+			return false;
+
+	return true;
+}
+
+/**
+ * dma_region_check_iova - check if memory area is fully contained in the region
+ * @region: dma memory region
+ * @iova: address of the dma memory area
+ * @size: size of the dma memory area
+ *
+ * Compare the dma memory area defined by @iova and @size with given dma region.
+ * Return true if memory area is fully contained in the region, otherwise false.
+ */
+static bool dma_region_check_iova(struct dfl_afu_dma_region *region,
+				  u64 iova, u64 size)
+{
+	if (!size && region->iova != iova)
+		return false;
+
+	return (region->iova <= iova) &&
+		(region->length + region->iova >= iova + size);
+}
+
+/**
+ * afu_dma_region_add - add given dma region to rbtree
+ * @pdata: feature device platform data
+ * @region: dma region to be added
+ *
+ * Return 0 for success, -EEXIST if dma region has already been added.
+ *
+ * Needs to be called with pdata->lock heold.
+ */
+static int afu_dma_region_add(struct dfl_feature_platform_data *pdata,
+			      struct dfl_afu_dma_region *region)
+{
+	struct dfl_afu *afu = dfl_fpga_pdata_get_private(pdata);
+	struct rb_node **new, *parent = NULL;
+
+	dev_dbg(&pdata->dev->dev, "add region (iova = %llx)\n",
+		(unsigned long long)region->iova);
+
+	new = &afu->dma_regions.rb_node;
+
+	while (*new) {
+		struct dfl_afu_dma_region *this;
+
+		this = container_of(*new, struct dfl_afu_dma_region, node);
+
+		parent = *new;
+
+		if (dma_region_check_iova(this, region->iova, region->length))
+			return -EEXIST;
+
+		if (region->iova < this->iova)
+			new = &((*new)->rb_left);
+		else if (region->iova > this->iova)
+			new = &((*new)->rb_right);
+		else
+			return -EEXIST;
+	}
+
+	rb_link_node(&region->node, parent, new);
+	rb_insert_color(&region->node, &afu->dma_regions);
+
+	return 0;
+}
+
+/**
+ * afu_dma_region_remove - remove given dma region from rbtree
+ * @pdata: feature device platform data
+ * @region: dma region to be removed
+ *
+ * Needs to be called with pdata->lock heold.
+ */
+static void afu_dma_region_remove(struct dfl_feature_platform_data *pdata,
+				  struct dfl_afu_dma_region *region)
+{
+	struct dfl_afu *afu;
+
+	dev_dbg(&pdata->dev->dev, "del region (iova = %llx)\n",
+		(unsigned long long)region->iova);
+
+	afu = dfl_fpga_pdata_get_private(pdata);
+	rb_erase(&region->node, &afu->dma_regions);
+}
+
+/**
+ * afu_dma_region_destroy - destroy all regions in rbtree
+ * @pdata: feature device platform data
+ *
+ * Needs to be called with pdata->lock heold.
+ */
+void afu_dma_region_destroy(struct dfl_feature_platform_data *pdata)
+{
+	struct dfl_afu *afu = dfl_fpga_pdata_get_private(pdata);
+	struct rb_node *node = rb_first(&afu->dma_regions);
+	struct dfl_afu_dma_region *region;
+
+	while (node) {
+		region = container_of(node, struct dfl_afu_dma_region, node);
+
+		dev_dbg(&pdata->dev->dev, "del region (iova = %llx)\n",
+			(unsigned long long)region->iova);
+
+		rb_erase(node, &afu->dma_regions);
+
+		if (region->iova)
+			dma_unmap_page(dfl_fpga_pdata_to_parent(pdata),
+				       region->iova, region->length,
+				       DMA_BIDIRECTIONAL);
+
+		if (region->pages)
+			afu_dma_unpin_pages(pdata, region);
+
+		node = rb_next(node);
+		kfree(region);
+	}
+}
+
+/**
+ * afu_dma_region_find - find the dma region from rbtree based on iova and size
+ * @pdata: feature device platform data
+ * @iova: address of the dma memory area
+ * @size: size of the dma memory area
+ *
+ * It finds the dma region from the rbtree based on @iova and @size:
+ * - if @size == 0, it finds the dma region which starts from @iova
+ * - otherwise, it finds the dma region which fully contains
+ *   [@iova, @iova+size)
+ * If nothing is matched returns NULL.
+ *
+ * Needs to be called with pdata->lock held.
+ */
+struct dfl_afu_dma_region *
+afu_dma_region_find(struct dfl_feature_platform_data *pdata, u64 iova, u64 size)
+{
+	struct dfl_afu *afu = dfl_fpga_pdata_get_private(pdata);
+	struct rb_node *node = afu->dma_regions.rb_node;
+	struct device *dev = &pdata->dev->dev;
+
+	while (node) {
+		struct dfl_afu_dma_region *region;
+
+		region = container_of(node, struct dfl_afu_dma_region, node);
+
+		if (dma_region_check_iova(region, iova, size)) {
+			dev_dbg(dev, "find region (iova = %llx)\n",
+				(unsigned long long)region->iova);
+			return region;
+		}
+
+		if (iova < region->iova)
+			node = node->rb_left;
+		else if (iova > region->iova)
+			node = node->rb_right;
+		else
+			/* the iova region is not fully covered. */
+			break;
+	}
+
+	dev_dbg(dev, "region with iova %llx and size %llx is not found\n",
+		(unsigned long long)iova, (unsigned long long)size);
+
+	return NULL;
+}
+
+/**
+ * afu_dma_region_find_iova - find the dma region from rbtree by iova
+ * @pdata: feature device platform data
+ * @iova: address of the dma region
+ *
+ * Needs to be called with pdata->lock held.
+ */
+static struct dfl_afu_dma_region *
+afu_dma_region_find_iova(struct dfl_feature_platform_data *pdata, u64 iova)
+{
+	return afu_dma_region_find(pdata, iova, 0);
+}
+
+/**
+ * afu_dma_map_region - map memory region for dma
+ * @pdata: feature device platform data
+ * @user_addr: address of the memory region
+ * @length: size of the memory region
+ * @iova: pointer of iova address
+ *
+ * Map memory region defined by @user_addr and @length, and return dma address
+ * of the memory region via @iova.
+ * Return 0 for success, otherwise error code.
+ */
+int afu_dma_map_region(struct dfl_feature_platform_data *pdata,
+		       u64 user_addr, u64 length, u64 *iova)
+{
+	struct dfl_afu_dma_region *region;
+	int ret;
+
+	/*
+	 * Check Inputs, only accept page-aligned user memory region with
+	 * valid length.
+	 */
+	if (!PAGE_ALIGNED(user_addr) || !PAGE_ALIGNED(length) || !length)
+		return -EINVAL;
+
+	/* Check overflow */
+	if (user_addr + length < user_addr)
+		return -EINVAL;
+
+	if (!access_ok(VERIFY_WRITE, (void __user *)(unsigned long)user_addr,
+		       length))
+		return -EINVAL;
+
+	region = kzalloc(sizeof(*region), GFP_KERNEL);
+	if (!region)
+		return -ENOMEM;
+
+	region->user_addr = user_addr;
+	region->length = length;
+
+	/* Pin the user memory region */
+	ret = afu_dma_pin_pages(pdata, region);
+	if (ret) {
+		dev_err(&pdata->dev->dev, "failed to pin memory region\n");
+		goto free_region;
+	}
+
+	/* Only accept continuous pages, return error else */
+	if (!afu_dma_check_continuous_pages(region)) {
+		dev_err(&pdata->dev->dev, "pages are not continuous\n");
+		ret = -EINVAL;
+		goto unpin_pages;
+	}
+
+	/* As pages are continuous then start to do DMA mapping */
+	region->iova = dma_map_page(dfl_fpga_pdata_to_parent(pdata),
+				    region->pages[0], 0,
+				    region->length,
+				    DMA_BIDIRECTIONAL);
+	if (dma_mapping_error(&pdata->dev->dev, region->iova)) {
+		dev_err(&pdata->dev->dev, "failed to map for dma\n");
+		ret = -EFAULT;
+		goto unpin_pages;
+	}
+
+	*iova = region->iova;
+
+	mutex_lock(&pdata->lock);
+	ret = afu_dma_region_add(pdata, region);
+	mutex_unlock(&pdata->lock);
+	if (ret) {
+		dev_err(&pdata->dev->dev, "failed to add dma region\n");
+		goto unmap_dma;
+	}
+
+	return 0;
+
+unmap_dma:
+	dma_unmap_page(dfl_fpga_pdata_to_parent(pdata),
+		       region->iova, region->length, DMA_BIDIRECTIONAL);
+unpin_pages:
+	afu_dma_unpin_pages(pdata, region);
+free_region:
+	kfree(region);
+	return ret;
+}
+
+/**
+ * afu_dma_unmap_region - unmap dma memory region
+ * @pdata: feature device platform data
+ * @iova: dma address of the region
+ *
+ * Unmap dma memory region based on @iova.
+ * Return 0 for success, otherwise error code.
+ */
+int afu_dma_unmap_region(struct dfl_feature_platform_data *pdata, u64 iova)
+{
+	struct dfl_afu_dma_region *region;
+
+	mutex_lock(&pdata->lock);
+	region = afu_dma_region_find_iova(pdata, iova);
+	if (!region) {
+		mutex_unlock(&pdata->lock);
+		return -EINVAL;
+	}
+
+	if (region->in_use) {
+		mutex_unlock(&pdata->lock);
+		return -EBUSY;
+	}
+
+	afu_dma_region_remove(pdata, region);
+	mutex_unlock(&pdata->lock);
+
+	dma_unmap_page(dfl_fpga_pdata_to_parent(pdata),
+		       region->iova, region->length, DMA_BIDIRECTIONAL);
+	afu_dma_unpin_pages(pdata, region);
+	kfree(region);
+
+	return 0;
+}