5 files changed, 591 insertions, 3 deletions

diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
index a44d50dd0b70..7a2d73ba7122 100644
--- a/drivers/fpga/Makefile
+++ b/drivers/fpga/Makefile
@@ -38,7 +38,7 @@ obj-$(CONFIG_FPGA_DFL_FME_REGION)	+= dfl-fme-region.o
 obj-$(CONFIG_FPGA_DFL_AFU)              += dfl-afu.o
 
 dfl-fme-objs := dfl-fme-main.o dfl-fme-pr.o
-dfl-afu-objs := dfl-afu-main.o dfl-afu-region.o
+dfl-afu-objs := dfl-afu-main.o dfl-afu-region.o dfl-afu-dma-region.o
 
 # Drivers for FPGAs which implement DFL
 obj-$(CONFIG_FPGA_DFL_PCI)              += dfl-pci.o
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.