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