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@@ -0,0 +1,805 @@
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+// 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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+
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+struct pci_p2pdma {
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+ struct percpu_ref devmap_ref;
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+ struct completion devmap_ref_done;
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+ struct gen_pool *pool;
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+ bool p2pmem_published;
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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 snprintf(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 snprintf(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 snprintf(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_percpu_release(struct percpu_ref *ref)
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+{
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+ struct pci_p2pdma *p2p =
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+ container_of(ref, struct pci_p2pdma, devmap_ref);
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+
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+ complete_all(&p2p->devmap_ref_done);
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+}
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+
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+static void pci_p2pdma_percpu_kill(void *data)
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+{
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+ struct percpu_ref *ref = data;
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+
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+ /*
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+ * pci_p2pdma_add_resource() may be called multiple times
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+ * by a driver and may register the percpu_kill devm action multiple
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+ * times. We only want the first action to actually kill the
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+ * percpu_ref.
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+ */
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+ if (percpu_ref_is_dying(ref))
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+ return;
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+
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+ percpu_ref_kill(ref);
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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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+
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+ if (!pdev->p2pdma)
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+ return;
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+
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+ wait_for_completion(&pdev->p2pdma->devmap_ref_done);
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+ percpu_ref_exit(&pdev->p2pdma->devmap_ref);
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+
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+ gen_pool_destroy(pdev->p2pdma->pool);
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+ sysfs_remove_group(&pdev->dev.kobj, &p2pmem_group);
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+ pdev->p2pdma = NULL;
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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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+ 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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+ init_completion(&p2p->devmap_ref_done);
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+ error = percpu_ref_init(&p2p->devmap_ref,
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+ pci_p2pdma_percpu_release, 0, GFP_KERNEL);
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+ if (error)
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+ goto out_pool_destroy;
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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 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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+ pgmap = devm_kzalloc(&pdev->dev, sizeof(*pgmap), GFP_KERNEL);
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+ if (!pgmap)
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+ return -ENOMEM;
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+
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+ pgmap->res.start = pci_resource_start(pdev, bar) + offset;
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+ pgmap->res.end = pgmap->res.start + size - 1;
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+ pgmap->res.flags = pci_resource_flags(pdev, bar);
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+ pgmap->ref = &pdev->p2pdma->devmap_ref;
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+ pgmap->type = MEMORY_DEVICE_PCI_P2PDMA;
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+ pgmap->pci_p2pdma_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_virt(pdev->p2pdma->pool, (unsigned long)addr,
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+ pci_bus_address(pdev, bar) + offset,
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+ resource_size(&pgmap->res), dev_to_node(&pdev->dev));
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+ if (error)
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+ goto pgmap_free;
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+
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+ error = devm_add_action_or_reset(&pdev->dev, pci_p2pdma_percpu_kill,
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+ &pdev->p2pdma->devmap_ref);
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+ if (error)
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+ goto pgmap_free;
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+
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+ pci_info(pdev, "added peer-to-peer DMA memory %pR\n",
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+ &pgmap->res);
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+
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+ return 0;
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+
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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 responsibily 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 = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ACS);
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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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+
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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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+/*
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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 don't have a common upstream bridge will return -1.
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+ * In this way devices on separate PCIe root ports will be rejected, which
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+ * is what we want for peer-to-peer seeing each PCIe root port defines a
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+ * separate hierarchy domain and there's no way to determine whether the root
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+ * complex supports forwarding between them.
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+ *
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+ * In the case where two devices are connected to different PCIe switches,
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+ * this function will still return a positive distance as long as both
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+ * switches eventually have a common upstream bridge. Note this covers
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+ * the case of using multiple PCIe switches to achieve a desired level of
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+ * fan-out from a root port. The exact distance will be a function of the
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+ * number of switches between Device A and Device B.
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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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+ * then this functions will return -2. This is so we reject any
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+ * cases where the TLPs are forwarded up into the root complex.
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+ * In this case, a list of all infringing bridge addresses will be
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+ * populated in acs_list (assuming it's non-null) for printk purposes.
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+ */
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+static int upstream_bridge_distance(struct pci_dev *a,
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+ struct pci_dev *b,
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+ struct seq_buf *acs_list)
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+{
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+ int dist_a = 0;
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+ int dist_b = 0;
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+ struct pci_dev *bb = NULL;
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+ int acs_cnt = 0;
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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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+ return -1;
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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 (acs_cnt)
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+ return -2;
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+
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+ return dist_a + dist_b;
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+}
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+
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+static int upstream_bridge_distance_warn(struct pci_dev *provider,
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+ struct pci_dev *client)
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+{
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+ struct seq_buf acs_list;
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+ int ret;
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+
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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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+
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+ ret = upstream_bridge_distance(provider, client, &acs_list);
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+ if (ret == -2) {
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+ pci_warn(client, "cannot be used for peer-to-peer DMA as 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",
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+ acs_list.buffer);
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+
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+ } else if (ret < 0) {
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+ pci_warn(client, "cannot be used for peer-to-peer DMA as the client and provider (%s) do not share an upstream bridge\n",
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+ pci_name(provider));
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+ }
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+
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+ kfree(acs_list.buffer);
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+
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+ return ret;
|
|
|
+}
|
|
|
+
|
|
|
+/**
|
|
|
+ * pci_p2pdma_distance_many - Determive the cumulative distance between
|
|
|
+ * a p2pdma provider and the clients in use.
|
|
|
+ * @provider: p2pdma provider to check against the client list
|
|
|
+ * @clients: array of devices to check (NULL-terminated)
|
|
|
+ * @num_clients: number of clients in the array
|
|
|
+ * @verbose: if true, print warnings for devices when we return -1
|
|
|
+ *
|
|
|
+ * Returns -1 if any of the clients are not compatible (behind the same
|
|
|
+ * root port as the provider), otherwise returns a positive number where
|
|
|
+ * a lower number is the preferrable choice. (If there's one client
|
|
|
+ * that's the same as the provider it will return 0, which is best choice).
|
|
|
+ *
|
|
|
+ * For now, "compatible" means the provider and the clients are all behind
|
|
|
+ * the same PCI root port. This cuts out cases that may work but is safest
|
|
|
+ * for the user. Future work can expand this to white-list root complexes that
|
|
|
+ * can safely forward between each ports.
|
|
|
+ */
|
|
|
+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 distance = 0;
|
|
|
+ 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);
|
|
|
+ else
|
|
|
+ ret = upstream_bridge_distance(provider, pci_client,
|
|
|
+ NULL);
|
|
|
+
|
|
|
+ pci_dev_put(pci_client);
|
|
|
+
|
|
|
+ if (ret < 0)
|
|
|
+ not_supported = true;
|
|
|
+
|
|
|
+ if (not_supported && !verbose)
|
|
|
+ break;
|
|
|
+
|
|
|
+ distance += ret;
|
|
|
+ }
|
|
|
+
|
|
|
+ if (not_supported)
|
|
|
+ return -1;
|
|
|
+
|
|
|
+ return distance;
|
|
|
+}
|
|
|
+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 - 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 are
|
|
|
+ * 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_p2p_mem - 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;
|
|
|
+
|
|
|
+ if (unlikely(!pdev->p2pdma))
|
|
|
+ return NULL;
|
|
|
+
|
|
|
+ if (unlikely(!percpu_ref_tryget_live(&pdev->p2pdma->devmap_ref)))
|
|
|
+ return NULL;
|
|
|
+
|
|
|
+ ret = (void *)gen_pool_alloc(pdev->p2pdma->pool, size);
|
|
|
+
|
|
|
+ if (unlikely(!ret))
|
|
|
+ percpu_ref_put(&pdev->p2pdma->devmap_ref);
|
|
|
+
|
|
|
+ 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 was allocated
|
|
|
+ */
|
|
|
+void pci_free_p2pmem(struct pci_dev *pdev, void *addr, size_t size)
|
|
|
+{
|
|
|
+ gen_pool_free(pdev->p2pdma->pool, (uintptr_t)addr, size);
|
|
|
+ percpu_ref_put(&pdev->p2pdma->devmap_ref);
|
|
|
+}
|
|
|
+EXPORT_SYMBOL_GPL(pci_free_p2pmem);
|
|
|
+
|
|
|
+/**
|
|
|
+ * pci_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
|
|
|
+ *
|
|
|
+ * Returns 0 on success
|
|
|
+ */
|
|
|
+struct scatterlist *pci_p2pmem_alloc_sgl(struct pci_dev *pdev,
|
|
|
+ unsigned int *nents, u32 length)
|
|
|
+{
|
|
|
+ struct scatterlist *sg;
|
|
|
+ void *addr;
|
|
|
+
|
|
|
+ sg = kzalloc(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
|
|
|
+ * exlusive 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);
|
|
|
+
|
|
|
+/**
|
|
|
+ * pci_p2pdma_map_sg - 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
|
|
|
+ *
|
|
|
+ * Scatterlists mapped with this function should not be unmapped in any way.
|
|
|
+ *
|
|
|
+ * Returns the number of SG entries mapped or 0 on error.
|
|
|
+ */
|
|
|
+int pci_p2pdma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
|
|
|
+ enum dma_data_direction dir)
|
|
|
+{
|
|
|
+ struct dev_pagemap *pgmap;
|
|
|
+ struct scatterlist *s;
|
|
|
+ phys_addr_t paddr;
|
|
|
+ int i;
|
|
|
+
|
|
|
+ /*
|
|
|
+ * p2pdma mappings are not compatible with devices that use
|
|
|
+ * dma_virt_ops. If the upper layers do the right thing
|
|
|
+ * this should never happen because it will be prevented
|
|
|
+ * by the check in pci_p2pdma_add_client()
|
|
|
+ */
|
|
|
+ if (WARN_ON_ONCE(IS_ENABLED(CONFIG_DMA_VIRT_OPS) &&
|
|
|
+ dev->dma_ops == &dma_virt_ops))
|
|
|
+ return 0;
|
|
|
+
|
|
|
+ for_each_sg(sg, s, nents, i) {
|
|
|
+ pgmap = sg_page(s)->pgmap;
|
|
|
+ paddr = sg_phys(s);
|
|
|
+
|
|
|
+ s->dma_address = paddr - pgmap->pci_p2pdma_bus_offset;
|
|
|
+ sg_dma_len(s) = s->length;
|
|
|
+ }
|
|
|
+
|
|
|
+ return nents;
|
|
|
+}
|
|
|
+EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg);
|
|
|
+
|
|
|
+/**
|
|
|
+ * 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 it's 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 p2pdme 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);
|
Bjorn Helgaas