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982 lines
25 KiB
982 lines
25 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* PCI Peer 2 Peer DMA support. |
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* |
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* Copyright (c) 2016-2018, Logan Gunthorpe |
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* Copyright (c) 2016-2017, Microsemi Corporation |
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* Copyright (c) 2017, Christoph Hellwig |
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* Copyright (c) 2018, Eideticom Inc. |
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*/ |
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|
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#define pr_fmt(fmt) "pci-p2pdma: " fmt |
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#include <linux/ctype.h> |
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#include <linux/pci-p2pdma.h> |
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#include <linux/module.h> |
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#include <linux/slab.h> |
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#include <linux/genalloc.h> |
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#include <linux/memremap.h> |
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#include <linux/percpu-refcount.h> |
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#include <linux/random.h> |
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#include <linux/seq_buf.h> |
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#include <linux/xarray.h> |
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|
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enum pci_p2pdma_map_type { |
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PCI_P2PDMA_MAP_UNKNOWN = 0, |
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PCI_P2PDMA_MAP_NOT_SUPPORTED, |
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PCI_P2PDMA_MAP_BUS_ADDR, |
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PCI_P2PDMA_MAP_THRU_HOST_BRIDGE, |
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}; |
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|
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struct pci_p2pdma { |
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struct gen_pool *pool; |
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bool p2pmem_published; |
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struct xarray map_types; |
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}; |
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|
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struct pci_p2pdma_pagemap { |
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struct dev_pagemap pgmap; |
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struct pci_dev *provider; |
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u64 bus_offset; |
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}; |
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|
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static struct pci_p2pdma_pagemap *to_p2p_pgmap(struct dev_pagemap *pgmap) |
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{ |
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return container_of(pgmap, struct pci_p2pdma_pagemap, pgmap); |
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} |
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|
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static ssize_t size_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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struct pci_dev *pdev = to_pci_dev(dev); |
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size_t size = 0; |
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|
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if (pdev->p2pdma->pool) |
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size = gen_pool_size(pdev->p2pdma->pool); |
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|
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return scnprintf(buf, PAGE_SIZE, "%zd\n", size); |
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} |
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static DEVICE_ATTR_RO(size); |
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|
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static ssize_t available_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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struct pci_dev *pdev = to_pci_dev(dev); |
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size_t avail = 0; |
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|
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if (pdev->p2pdma->pool) |
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avail = gen_pool_avail(pdev->p2pdma->pool); |
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|
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return scnprintf(buf, PAGE_SIZE, "%zd\n", avail); |
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} |
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static DEVICE_ATTR_RO(available); |
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|
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static ssize_t published_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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struct pci_dev *pdev = to_pci_dev(dev); |
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|
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return scnprintf(buf, PAGE_SIZE, "%d\n", |
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pdev->p2pdma->p2pmem_published); |
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} |
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static DEVICE_ATTR_RO(published); |
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|
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static struct attribute *p2pmem_attrs[] = { |
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&dev_attr_size.attr, |
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&dev_attr_available.attr, |
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&dev_attr_published.attr, |
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NULL, |
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}; |
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|
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static const struct attribute_group p2pmem_group = { |
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.attrs = p2pmem_attrs, |
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.name = "p2pmem", |
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}; |
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|
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static void pci_p2pdma_release(void *data) |
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{ |
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struct pci_dev *pdev = data; |
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struct pci_p2pdma *p2pdma = pdev->p2pdma; |
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|
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if (!p2pdma) |
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return; |
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|
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/* Flush and disable pci_alloc_p2p_mem() */ |
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pdev->p2pdma = NULL; |
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synchronize_rcu(); |
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|
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gen_pool_destroy(p2pdma->pool); |
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sysfs_remove_group(&pdev->dev.kobj, &p2pmem_group); |
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xa_destroy(&p2pdma->map_types); |
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} |
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|
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static int pci_p2pdma_setup(struct pci_dev *pdev) |
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{ |
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int error = -ENOMEM; |
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struct pci_p2pdma *p2p; |
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|
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p2p = devm_kzalloc(&pdev->dev, sizeof(*p2p), GFP_KERNEL); |
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if (!p2p) |
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return -ENOMEM; |
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|
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xa_init(&p2p->map_types); |
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|
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p2p->pool = gen_pool_create(PAGE_SHIFT, dev_to_node(&pdev->dev)); |
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if (!p2p->pool) |
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goto out; |
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|
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error = devm_add_action_or_reset(&pdev->dev, pci_p2pdma_release, pdev); |
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if (error) |
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goto out_pool_destroy; |
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|
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pdev->p2pdma = p2p; |
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|
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error = sysfs_create_group(&pdev->dev.kobj, &p2pmem_group); |
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if (error) |
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goto out_pool_destroy; |
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|
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return 0; |
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|
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out_pool_destroy: |
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pdev->p2pdma = NULL; |
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gen_pool_destroy(p2p->pool); |
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out: |
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devm_kfree(&pdev->dev, p2p); |
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return error; |
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} |
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|
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/** |
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* pci_p2pdma_add_resource - add memory for use as p2p memory |
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* @pdev: the device to add the memory to |
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* @bar: PCI BAR to add |
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* @size: size of the memory to add, may be zero to use the whole BAR |
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* @offset: offset into the PCI BAR |
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* |
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* The memory will be given ZONE_DEVICE struct pages so that it may |
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* be used with any DMA request. |
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*/ |
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int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size, |
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u64 offset) |
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{ |
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struct pci_p2pdma_pagemap *p2p_pgmap; |
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struct dev_pagemap *pgmap; |
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void *addr; |
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int error; |
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|
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if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM)) |
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return -EINVAL; |
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|
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if (offset >= pci_resource_len(pdev, bar)) |
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return -EINVAL; |
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|
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if (!size) |
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size = pci_resource_len(pdev, bar) - offset; |
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|
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if (size + offset > pci_resource_len(pdev, bar)) |
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return -EINVAL; |
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|
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if (!pdev->p2pdma) { |
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error = pci_p2pdma_setup(pdev); |
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if (error) |
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return error; |
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} |
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|
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p2p_pgmap = devm_kzalloc(&pdev->dev, sizeof(*p2p_pgmap), GFP_KERNEL); |
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if (!p2p_pgmap) |
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return -ENOMEM; |
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|
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pgmap = &p2p_pgmap->pgmap; |
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pgmap->range.start = pci_resource_start(pdev, bar) + offset; |
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pgmap->range.end = pgmap->range.start + size - 1; |
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pgmap->nr_range = 1; |
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pgmap->type = MEMORY_DEVICE_PCI_P2PDMA; |
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|
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p2p_pgmap->provider = pdev; |
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p2p_pgmap->bus_offset = pci_bus_address(pdev, bar) - |
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pci_resource_start(pdev, bar); |
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|
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addr = devm_memremap_pages(&pdev->dev, pgmap); |
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if (IS_ERR(addr)) { |
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error = PTR_ERR(addr); |
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goto pgmap_free; |
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} |
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|
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error = gen_pool_add_owner(pdev->p2pdma->pool, (unsigned long)addr, |
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pci_bus_address(pdev, bar) + offset, |
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range_len(&pgmap->range), dev_to_node(&pdev->dev), |
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pgmap->ref); |
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if (error) |
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goto pages_free; |
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|
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pci_info(pdev, "added peer-to-peer DMA memory %#llx-%#llx\n", |
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pgmap->range.start, pgmap->range.end); |
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|
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return 0; |
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|
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pages_free: |
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devm_memunmap_pages(&pdev->dev, pgmap); |
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pgmap_free: |
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devm_kfree(&pdev->dev, pgmap); |
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return error; |
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} |
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EXPORT_SYMBOL_GPL(pci_p2pdma_add_resource); |
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|
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/* |
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* Note this function returns the parent PCI device with a |
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* reference taken. It is the caller's responsibility to drop |
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* the reference. |
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*/ |
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static struct pci_dev *find_parent_pci_dev(struct device *dev) |
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{ |
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struct device *parent; |
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|
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dev = get_device(dev); |
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|
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while (dev) { |
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if (dev_is_pci(dev)) |
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return to_pci_dev(dev); |
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|
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parent = get_device(dev->parent); |
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put_device(dev); |
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dev = parent; |
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} |
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|
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return NULL; |
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} |
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|
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/* |
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* Check if a PCI bridge has its ACS redirection bits set to redirect P2P |
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* TLPs upstream via ACS. Returns 1 if the packets will be redirected |
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* upstream, 0 otherwise. |
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*/ |
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static int pci_bridge_has_acs_redir(struct pci_dev *pdev) |
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{ |
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int pos; |
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u16 ctrl; |
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|
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pos = pdev->acs_cap; |
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if (!pos) |
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return 0; |
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|
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pci_read_config_word(pdev, pos + PCI_ACS_CTRL, &ctrl); |
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|
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if (ctrl & (PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_EC)) |
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return 1; |
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return 0; |
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} |
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|
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static void seq_buf_print_bus_devfn(struct seq_buf *buf, struct pci_dev *pdev) |
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{ |
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if (!buf) |
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return; |
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|
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seq_buf_printf(buf, "%s;", pci_name(pdev)); |
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} |
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|
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static bool cpu_supports_p2pdma(void) |
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{ |
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#ifdef CONFIG_X86 |
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struct cpuinfo_x86 *c = &cpu_data(0); |
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|
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/* Any AMD CPU whose family ID is Zen or newer supports p2pdma */ |
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if (c->x86_vendor == X86_VENDOR_AMD && c->x86 >= 0x17) |
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return true; |
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#endif |
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|
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return false; |
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} |
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|
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static const struct pci_p2pdma_whitelist_entry { |
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unsigned short vendor; |
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unsigned short device; |
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enum { |
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REQ_SAME_HOST_BRIDGE = 1 << 0, |
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} flags; |
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} pci_p2pdma_whitelist[] = { |
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/* Intel Xeon E5/Core i7 */ |
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{PCI_VENDOR_ID_INTEL, 0x3c00, REQ_SAME_HOST_BRIDGE}, |
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{PCI_VENDOR_ID_INTEL, 0x3c01, REQ_SAME_HOST_BRIDGE}, |
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/* Intel Xeon E7 v3/Xeon E5 v3/Core i7 */ |
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{PCI_VENDOR_ID_INTEL, 0x2f00, REQ_SAME_HOST_BRIDGE}, |
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{PCI_VENDOR_ID_INTEL, 0x2f01, REQ_SAME_HOST_BRIDGE}, |
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/* Intel SkyLake-E */ |
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{PCI_VENDOR_ID_INTEL, 0x2030, 0}, |
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{PCI_VENDOR_ID_INTEL, 0x2031, 0}, |
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{PCI_VENDOR_ID_INTEL, 0x2032, 0}, |
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{PCI_VENDOR_ID_INTEL, 0x2033, 0}, |
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{PCI_VENDOR_ID_INTEL, 0x2020, 0}, |
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{} |
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}; |
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|
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static bool __host_bridge_whitelist(struct pci_host_bridge *host, |
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bool same_host_bridge) |
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{ |
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struct pci_dev *root = pci_get_slot(host->bus, PCI_DEVFN(0, 0)); |
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const struct pci_p2pdma_whitelist_entry *entry; |
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unsigned short vendor, device; |
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|
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if (!root) |
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return false; |
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vendor = root->vendor; |
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device = root->device; |
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pci_dev_put(root); |
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|
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for (entry = pci_p2pdma_whitelist; entry->vendor; entry++) { |
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if (vendor != entry->vendor || device != entry->device) |
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continue; |
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if (entry->flags & REQ_SAME_HOST_BRIDGE && !same_host_bridge) |
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return false; |
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|
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return true; |
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} |
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return false; |
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} |
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|
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/* |
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* If we can't find a common upstream bridge take a look at the root |
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* complex and compare it to a whitelist of known good hardware. |
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*/ |
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static bool host_bridge_whitelist(struct pci_dev *a, struct pci_dev *b) |
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{ |
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struct pci_host_bridge *host_a = pci_find_host_bridge(a->bus); |
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struct pci_host_bridge *host_b = pci_find_host_bridge(b->bus); |
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|
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if (host_a == host_b) |
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return __host_bridge_whitelist(host_a, true); |
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|
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if (__host_bridge_whitelist(host_a, false) && |
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__host_bridge_whitelist(host_b, false)) |
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return true; |
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|
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return false; |
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} |
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|
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static enum pci_p2pdma_map_type |
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__upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, |
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int *dist, bool *acs_redirects, struct seq_buf *acs_list) |
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{ |
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struct pci_dev *a = provider, *b = client, *bb; |
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int dist_a = 0; |
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int dist_b = 0; |
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int acs_cnt = 0; |
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|
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if (acs_redirects) |
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*acs_redirects = false; |
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|
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/* |
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* Note, we don't need to take references to devices returned by |
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* pci_upstream_bridge() seeing we hold a reference to a child |
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* device which will already hold a reference to the upstream bridge. |
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*/ |
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|
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while (a) { |
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dist_b = 0; |
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|
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if (pci_bridge_has_acs_redir(a)) { |
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seq_buf_print_bus_devfn(acs_list, a); |
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acs_cnt++; |
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} |
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|
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bb = b; |
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|
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while (bb) { |
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if (a == bb) |
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goto check_b_path_acs; |
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|
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bb = pci_upstream_bridge(bb); |
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dist_b++; |
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} |
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|
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a = pci_upstream_bridge(a); |
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dist_a++; |
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} |
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|
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if (dist) |
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*dist = dist_a + dist_b; |
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|
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return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE; |
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|
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check_b_path_acs: |
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bb = b; |
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|
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while (bb) { |
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if (a == bb) |
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break; |
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|
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if (pci_bridge_has_acs_redir(bb)) { |
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seq_buf_print_bus_devfn(acs_list, bb); |
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acs_cnt++; |
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} |
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|
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bb = pci_upstream_bridge(bb); |
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} |
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|
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if (dist) |
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*dist = dist_a + dist_b; |
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|
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if (acs_cnt) { |
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if (acs_redirects) |
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*acs_redirects = true; |
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|
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return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE; |
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} |
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|
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return PCI_P2PDMA_MAP_BUS_ADDR; |
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} |
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|
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static unsigned long map_types_idx(struct pci_dev *client) |
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{ |
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return (pci_domain_nr(client->bus) << 16) | |
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(client->bus->number << 8) | client->devfn; |
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} |
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|
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/* |
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* Find the distance through the nearest common upstream bridge between |
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* two PCI devices. |
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* |
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* If the two devices are the same device then 0 will be returned. |
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* |
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* If there are two virtual functions of the same device behind the same |
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* bridge port then 2 will be returned (one step down to the PCIe switch, |
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* then one step back to the same device). |
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* |
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* In the case where two devices are connected to the same PCIe switch, the |
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* value 4 will be returned. This corresponds to the following PCI tree: |
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* |
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* -+ Root Port |
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* \+ Switch Upstream Port |
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* +-+ Switch Downstream Port |
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* + \- Device A |
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* \-+ Switch Downstream Port |
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* \- Device B |
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* |
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* The distance is 4 because we traverse from Device A through the downstream |
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* port of the switch, to the common upstream port, back up to the second |
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* downstream port and then to Device B. |
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* |
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* Any two devices that cannot communicate using p2pdma will return |
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* PCI_P2PDMA_MAP_NOT_SUPPORTED. |
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* |
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* Any two devices that have a data path that goes through the host bridge |
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* will consult a whitelist. If the host bridges are on the whitelist, |
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* this function will return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE. |
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* |
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* If either bridge is not on the whitelist this function returns |
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* PCI_P2PDMA_MAP_NOT_SUPPORTED. |
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* |
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* If a bridge which has any ACS redirection bits set is in the path, |
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* acs_redirects will be set to true. In this case, a list of all infringing |
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* bridge addresses will be populated in acs_list (assuming it's non-null) |
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* for printk purposes. |
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*/ |
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static enum pci_p2pdma_map_type |
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upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, |
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int *dist, bool *acs_redirects, struct seq_buf *acs_list) |
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{ |
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enum pci_p2pdma_map_type map_type; |
|
|
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map_type = __upstream_bridge_distance(provider, client, dist, |
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acs_redirects, acs_list); |
|
|
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if (map_type == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE) { |
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if (!cpu_supports_p2pdma() && |
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!host_bridge_whitelist(provider, client)) |
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map_type = PCI_P2PDMA_MAP_NOT_SUPPORTED; |
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} |
|
|
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if (provider->p2pdma) |
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xa_store(&provider->p2pdma->map_types, map_types_idx(client), |
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xa_mk_value(map_type), GFP_KERNEL); |
|
|
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return map_type; |
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} |
|
|
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static enum pci_p2pdma_map_type |
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upstream_bridge_distance_warn(struct pci_dev *provider, struct pci_dev *client, |
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int *dist) |
|
{ |
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struct seq_buf acs_list; |
|
bool acs_redirects; |
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int ret; |
|
|
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seq_buf_init(&acs_list, kmalloc(PAGE_SIZE, GFP_KERNEL), PAGE_SIZE); |
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if (!acs_list.buffer) |
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return -ENOMEM; |
|
|
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ret = upstream_bridge_distance(provider, client, dist, &acs_redirects, |
|
&acs_list); |
|
if (acs_redirects) { |
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pci_warn(client, "ACS redirect is set between the client and provider (%s)\n", |
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pci_name(provider)); |
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/* Drop final semicolon */ |
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acs_list.buffer[acs_list.len-1] = 0; |
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pci_warn(client, "to disable ACS redirect for this path, add the kernel parameter: pci=disable_acs_redir=%s\n", |
|
acs_list.buffer); |
|
} |
|
|
|
if (ret == PCI_P2PDMA_MAP_NOT_SUPPORTED) { |
|
pci_warn(client, "cannot be used for peer-to-peer DMA as the client and provider (%s) do not share an upstream bridge or whitelisted host bridge\n", |
|
pci_name(provider)); |
|
} |
|
|
|
kfree(acs_list.buffer); |
|
|
|
return ret; |
|
} |
|
|
|
/** |
|
* pci_p2pdma_distance_many - Determine the cumulative distance between |
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* a p2pdma provider and the clients in use. |
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* @provider: p2pdma provider to check against the client list |
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* @clients: array of devices to check (NULL-terminated) |
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* @num_clients: number of clients in the array |
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* @verbose: if true, print warnings for devices when we return -1 |
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* |
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* Returns -1 if any of the clients are not compatible, otherwise returns a |
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* positive number where a lower number is the preferable choice. (If there's |
|
* one client that's the same as the provider it will return 0, which is best |
|
* choice). |
|
* |
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* "compatible" means the provider and the clients are either all behind |
|
* the same PCI root port or the host bridges connected to each of the devices |
|
* are listed in the 'pci_p2pdma_whitelist'. |
|
*/ |
|
int pci_p2pdma_distance_many(struct pci_dev *provider, struct device **clients, |
|
int num_clients, bool verbose) |
|
{ |
|
bool not_supported = false; |
|
struct pci_dev *pci_client; |
|
int total_dist = 0; |
|
int distance; |
|
int i, ret; |
|
|
|
if (num_clients == 0) |
|
return -1; |
|
|
|
for (i = 0; i < num_clients; i++) { |
|
pci_client = find_parent_pci_dev(clients[i]); |
|
if (!pci_client) { |
|
if (verbose) |
|
dev_warn(clients[i], |
|
"cannot be used for peer-to-peer DMA as it is not a PCI device\n"); |
|
return -1; |
|
} |
|
|
|
if (verbose) |
|
ret = upstream_bridge_distance_warn(provider, |
|
pci_client, &distance); |
|
else |
|
ret = upstream_bridge_distance(provider, pci_client, |
|
&distance, NULL, NULL); |
|
|
|
pci_dev_put(pci_client); |
|
|
|
if (ret == PCI_P2PDMA_MAP_NOT_SUPPORTED) |
|
not_supported = true; |
|
|
|
if (not_supported && !verbose) |
|
break; |
|
|
|
total_dist += distance; |
|
} |
|
|
|
if (not_supported) |
|
return -1; |
|
|
|
return total_dist; |
|
} |
|
EXPORT_SYMBOL_GPL(pci_p2pdma_distance_many); |
|
|
|
/** |
|
* pci_has_p2pmem - check if a given PCI device has published any p2pmem |
|
* @pdev: PCI device to check |
|
*/ |
|
bool pci_has_p2pmem(struct pci_dev *pdev) |
|
{ |
|
return pdev->p2pdma && pdev->p2pdma->p2pmem_published; |
|
} |
|
EXPORT_SYMBOL_GPL(pci_has_p2pmem); |
|
|
|
/** |
|
* pci_p2pmem_find_many - find a peer-to-peer DMA memory device compatible with |
|
* the specified list of clients and shortest distance (as determined |
|
* by pci_p2pmem_dma()) |
|
* @clients: array of devices to check (NULL-terminated) |
|
* @num_clients: number of client devices in the list |
|
* |
|
* If multiple devices are behind the same switch, the one "closest" to the |
|
* client devices in use will be chosen first. (So if one of the providers is |
|
* the same as one of the clients, that provider will be used ahead of any |
|
* other providers that are unrelated). If multiple providers are an equal |
|
* distance away, one will be chosen at random. |
|
* |
|
* Returns a pointer to the PCI device with a reference taken (use pci_dev_put |
|
* to return the reference) or NULL if no compatible device is found. The |
|
* found provider will also be assigned to the client list. |
|
*/ |
|
struct pci_dev *pci_p2pmem_find_many(struct device **clients, int num_clients) |
|
{ |
|
struct pci_dev *pdev = NULL; |
|
int distance; |
|
int closest_distance = INT_MAX; |
|
struct pci_dev **closest_pdevs; |
|
int dev_cnt = 0; |
|
const int max_devs = PAGE_SIZE / sizeof(*closest_pdevs); |
|
int i; |
|
|
|
closest_pdevs = kmalloc(PAGE_SIZE, GFP_KERNEL); |
|
if (!closest_pdevs) |
|
return NULL; |
|
|
|
while ((pdev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, pdev))) { |
|
if (!pci_has_p2pmem(pdev)) |
|
continue; |
|
|
|
distance = pci_p2pdma_distance_many(pdev, clients, |
|
num_clients, false); |
|
if (distance < 0 || distance > closest_distance) |
|
continue; |
|
|
|
if (distance == closest_distance && dev_cnt >= max_devs) |
|
continue; |
|
|
|
if (distance < closest_distance) { |
|
for (i = 0; i < dev_cnt; i++) |
|
pci_dev_put(closest_pdevs[i]); |
|
|
|
dev_cnt = 0; |
|
closest_distance = distance; |
|
} |
|
|
|
closest_pdevs[dev_cnt++] = pci_dev_get(pdev); |
|
} |
|
|
|
if (dev_cnt) |
|
pdev = pci_dev_get(closest_pdevs[prandom_u32_max(dev_cnt)]); |
|
|
|
for (i = 0; i < dev_cnt; i++) |
|
pci_dev_put(closest_pdevs[i]); |
|
|
|
kfree(closest_pdevs); |
|
return pdev; |
|
} |
|
EXPORT_SYMBOL_GPL(pci_p2pmem_find_many); |
|
|
|
/** |
|
* pci_alloc_p2pmem - allocate peer-to-peer DMA memory |
|
* @pdev: the device to allocate memory from |
|
* @size: number of bytes to allocate |
|
* |
|
* Returns the allocated memory or NULL on error. |
|
*/ |
|
void *pci_alloc_p2pmem(struct pci_dev *pdev, size_t size) |
|
{ |
|
void *ret = NULL; |
|
struct percpu_ref *ref; |
|
|
|
/* |
|
* Pairs with synchronize_rcu() in pci_p2pdma_release() to |
|
* ensure pdev->p2pdma is non-NULL for the duration of the |
|
* read-lock. |
|
*/ |
|
rcu_read_lock(); |
|
if (unlikely(!pdev->p2pdma)) |
|
goto out; |
|
|
|
ret = (void *)gen_pool_alloc_owner(pdev->p2pdma->pool, size, |
|
(void **) &ref); |
|
if (!ret) |
|
goto out; |
|
|
|
if (unlikely(!percpu_ref_tryget_live(ref))) { |
|
gen_pool_free(pdev->p2pdma->pool, (unsigned long) ret, size); |
|
ret = NULL; |
|
goto out; |
|
} |
|
out: |
|
rcu_read_unlock(); |
|
return ret; |
|
} |
|
EXPORT_SYMBOL_GPL(pci_alloc_p2pmem); |
|
|
|
/** |
|
* pci_free_p2pmem - free peer-to-peer DMA memory |
|
* @pdev: the device the memory was allocated from |
|
* @addr: address of the memory that was allocated |
|
* @size: number of bytes that were allocated |
|
*/ |
|
void pci_free_p2pmem(struct pci_dev *pdev, void *addr, size_t size) |
|
{ |
|
struct percpu_ref *ref; |
|
|
|
gen_pool_free_owner(pdev->p2pdma->pool, (uintptr_t)addr, size, |
|
(void **) &ref); |
|
percpu_ref_put(ref); |
|
} |
|
EXPORT_SYMBOL_GPL(pci_free_p2pmem); |
|
|
|
/** |
|
* pci_p2pmem_virt_to_bus - return the PCI bus address for a given virtual |
|
* address obtained with pci_alloc_p2pmem() |
|
* @pdev: the device the memory was allocated from |
|
* @addr: address of the memory that was allocated |
|
*/ |
|
pci_bus_addr_t pci_p2pmem_virt_to_bus(struct pci_dev *pdev, void *addr) |
|
{ |
|
if (!addr) |
|
return 0; |
|
if (!pdev->p2pdma) |
|
return 0; |
|
|
|
/* |
|
* Note: when we added the memory to the pool we used the PCI |
|
* bus address as the physical address. So gen_pool_virt_to_phys() |
|
* actually returns the bus address despite the misleading name. |
|
*/ |
|
return gen_pool_virt_to_phys(pdev->p2pdma->pool, (unsigned long)addr); |
|
} |
|
EXPORT_SYMBOL_GPL(pci_p2pmem_virt_to_bus); |
|
|
|
/** |
|
* pci_p2pmem_alloc_sgl - allocate peer-to-peer DMA memory in a scatterlist |
|
* @pdev: the device to allocate memory from |
|
* @nents: the number of SG entries in the list |
|
* @length: number of bytes to allocate |
|
* |
|
* Return: %NULL on error or &struct scatterlist pointer and @nents on success |
|
*/ |
|
struct scatterlist *pci_p2pmem_alloc_sgl(struct pci_dev *pdev, |
|
unsigned int *nents, u32 length) |
|
{ |
|
struct scatterlist *sg; |
|
void *addr; |
|
|
|
sg = kmalloc(sizeof(*sg), GFP_KERNEL); |
|
if (!sg) |
|
return NULL; |
|
|
|
sg_init_table(sg, 1); |
|
|
|
addr = pci_alloc_p2pmem(pdev, length); |
|
if (!addr) |
|
goto out_free_sg; |
|
|
|
sg_set_buf(sg, addr, length); |
|
*nents = 1; |
|
return sg; |
|
|
|
out_free_sg: |
|
kfree(sg); |
|
return NULL; |
|
} |
|
EXPORT_SYMBOL_GPL(pci_p2pmem_alloc_sgl); |
|
|
|
/** |
|
* pci_p2pmem_free_sgl - free a scatterlist allocated by pci_p2pmem_alloc_sgl() |
|
* @pdev: the device to allocate memory from |
|
* @sgl: the allocated scatterlist |
|
*/ |
|
void pci_p2pmem_free_sgl(struct pci_dev *pdev, struct scatterlist *sgl) |
|
{ |
|
struct scatterlist *sg; |
|
int count; |
|
|
|
for_each_sg(sgl, sg, INT_MAX, count) { |
|
if (!sg) |
|
break; |
|
|
|
pci_free_p2pmem(pdev, sg_virt(sg), sg->length); |
|
} |
|
kfree(sgl); |
|
} |
|
EXPORT_SYMBOL_GPL(pci_p2pmem_free_sgl); |
|
|
|
/** |
|
* pci_p2pmem_publish - publish the peer-to-peer DMA memory for use by |
|
* other devices with pci_p2pmem_find() |
|
* @pdev: the device with peer-to-peer DMA memory to publish |
|
* @publish: set to true to publish the memory, false to unpublish it |
|
* |
|
* Published memory can be used by other PCI device drivers for |
|
* peer-2-peer DMA operations. Non-published memory is reserved for |
|
* exclusive use of the device driver that registers the peer-to-peer |
|
* memory. |
|
*/ |
|
void pci_p2pmem_publish(struct pci_dev *pdev, bool publish) |
|
{ |
|
if (pdev->p2pdma) |
|
pdev->p2pdma->p2pmem_published = publish; |
|
} |
|
EXPORT_SYMBOL_GPL(pci_p2pmem_publish); |
|
|
|
static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct pci_dev *provider, |
|
struct pci_dev *client) |
|
{ |
|
if (!provider->p2pdma) |
|
return PCI_P2PDMA_MAP_NOT_SUPPORTED; |
|
|
|
return xa_to_value(xa_load(&provider->p2pdma->map_types, |
|
map_types_idx(client))); |
|
} |
|
|
|
static int __pci_p2pdma_map_sg(struct pci_p2pdma_pagemap *p2p_pgmap, |
|
struct device *dev, struct scatterlist *sg, int nents) |
|
{ |
|
struct scatterlist *s; |
|
int i; |
|
|
|
for_each_sg(sg, s, nents, i) { |
|
s->dma_address = sg_phys(s) - p2p_pgmap->bus_offset; |
|
sg_dma_len(s) = s->length; |
|
} |
|
|
|
return nents; |
|
} |
|
|
|
/** |
|
* pci_p2pdma_map_sg_attrs - map a PCI peer-to-peer scatterlist for DMA |
|
* @dev: device doing the DMA request |
|
* @sg: scatter list to map |
|
* @nents: elements in the scatterlist |
|
* @dir: DMA direction |
|
* @attrs: DMA attributes passed to dma_map_sg() (if called) |
|
* |
|
* Scatterlists mapped with this function should be unmapped using |
|
* pci_p2pdma_unmap_sg_attrs(). |
|
* |
|
* Returns the number of SG entries mapped or 0 on error. |
|
*/ |
|
int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg, |
|
int nents, enum dma_data_direction dir, unsigned long attrs) |
|
{ |
|
struct pci_p2pdma_pagemap *p2p_pgmap = |
|
to_p2p_pgmap(sg_page(sg)->pgmap); |
|
struct pci_dev *client; |
|
|
|
if (WARN_ON_ONCE(!dev_is_pci(dev))) |
|
return 0; |
|
|
|
client = to_pci_dev(dev); |
|
|
|
switch (pci_p2pdma_map_type(p2p_pgmap->provider, client)) { |
|
case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE: |
|
return dma_map_sg_attrs(dev, sg, nents, dir, attrs); |
|
case PCI_P2PDMA_MAP_BUS_ADDR: |
|
return __pci_p2pdma_map_sg(p2p_pgmap, dev, sg, nents); |
|
default: |
|
WARN_ON_ONCE(1); |
|
return 0; |
|
} |
|
} |
|
EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg_attrs); |
|
|
|
/** |
|
* pci_p2pdma_unmap_sg_attrs - unmap a PCI peer-to-peer scatterlist that was |
|
* mapped with pci_p2pdma_map_sg() |
|
* @dev: device doing the DMA request |
|
* @sg: scatter list to map |
|
* @nents: number of elements returned by pci_p2pdma_map_sg() |
|
* @dir: DMA direction |
|
* @attrs: DMA attributes passed to dma_unmap_sg() (if called) |
|
*/ |
|
void pci_p2pdma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg, |
|
int nents, enum dma_data_direction dir, unsigned long attrs) |
|
{ |
|
struct pci_p2pdma_pagemap *p2p_pgmap = |
|
to_p2p_pgmap(sg_page(sg)->pgmap); |
|
enum pci_p2pdma_map_type map_type; |
|
struct pci_dev *client; |
|
|
|
if (WARN_ON_ONCE(!dev_is_pci(dev))) |
|
return; |
|
|
|
client = to_pci_dev(dev); |
|
|
|
map_type = pci_p2pdma_map_type(p2p_pgmap->provider, client); |
|
|
|
if (map_type == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE) |
|
dma_unmap_sg_attrs(dev, sg, nents, dir, attrs); |
|
} |
|
EXPORT_SYMBOL_GPL(pci_p2pdma_unmap_sg_attrs); |
|
|
|
/** |
|
* pci_p2pdma_enable_store - parse a configfs/sysfs attribute store |
|
* to enable p2pdma |
|
* @page: contents of the value to be stored |
|
* @p2p_dev: returns the PCI device that was selected to be used |
|
* (if one was specified in the stored value) |
|
* @use_p2pdma: returns whether to enable p2pdma or not |
|
* |
|
* Parses an attribute value to decide whether to enable p2pdma. |
|
* The value can select a PCI device (using its full BDF device |
|
* name) or a boolean (in any format strtobool() accepts). A false |
|
* value disables p2pdma, a true value expects the caller |
|
* to automatically find a compatible device and specifying a PCI device |
|
* expects the caller to use the specific provider. |
|
* |
|
* pci_p2pdma_enable_show() should be used as the show operation for |
|
* the attribute. |
|
* |
|
* Returns 0 on success |
|
*/ |
|
int pci_p2pdma_enable_store(const char *page, struct pci_dev **p2p_dev, |
|
bool *use_p2pdma) |
|
{ |
|
struct device *dev; |
|
|
|
dev = bus_find_device_by_name(&pci_bus_type, NULL, page); |
|
if (dev) { |
|
*use_p2pdma = true; |
|
*p2p_dev = to_pci_dev(dev); |
|
|
|
if (!pci_has_p2pmem(*p2p_dev)) { |
|
pci_err(*p2p_dev, |
|
"PCI device has no peer-to-peer memory: %s\n", |
|
page); |
|
pci_dev_put(*p2p_dev); |
|
return -ENODEV; |
|
} |
|
|
|
return 0; |
|
} else if ((page[0] == '0' || page[0] == '1') && !iscntrl(page[1])) { |
|
/* |
|
* If the user enters a PCI device that doesn't exist |
|
* like "0000:01:00.1", we don't want strtobool to think |
|
* it's a '0' when it's clearly not what the user wanted. |
|
* So we require 0's and 1's to be exactly one character. |
|
*/ |
|
} else if (!strtobool(page, use_p2pdma)) { |
|
return 0; |
|
} |
|
|
|
pr_err("No such PCI device: %.*s\n", (int)strcspn(page, "\n"), page); |
|
return -ENODEV; |
|
} |
|
EXPORT_SYMBOL_GPL(pci_p2pdma_enable_store); |
|
|
|
/** |
|
* pci_p2pdma_enable_show - show a configfs/sysfs attribute indicating |
|
* whether p2pdma is enabled |
|
* @page: contents of the stored value |
|
* @p2p_dev: the selected p2p device (NULL if no device is selected) |
|
* @use_p2pdma: whether p2pdma has been enabled |
|
* |
|
* Attributes that use pci_p2pdma_enable_store() should use this function |
|
* to show the value of the attribute. |
|
* |
|
* Returns 0 on success |
|
*/ |
|
ssize_t pci_p2pdma_enable_show(char *page, struct pci_dev *p2p_dev, |
|
bool use_p2pdma) |
|
{ |
|
if (!use_p2pdma) |
|
return sprintf(page, "0\n"); |
|
|
|
if (!p2p_dev) |
|
return sprintf(page, "1\n"); |
|
|
|
return sprintf(page, "%s\n", pci_name(p2p_dev)); |
|
} |
|
EXPORT_SYMBOL_GPL(pci_p2pdma_enable_show);
|
|
|