123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708709710711712713714715716717718719720721722723724725726727728729730731732733734735736737738739740741742743744745746747748749750751752753754755756757758759760761762763764765766767768769770771772773774775776777778779780781782783784785786787788789790791792793794795796797798799800801802803804805806807808809810811812813814815816817818819820821822823824825826827828829830831832833834835836837838839840841842843844845846847848849850851852853854855856857858859860861862863864865866867868869870871872873874875876877878879880881882883884885886887888889890891892893894895896897898899900901902903904905906907908909910911912913914915916917918919920921922923924925926927928929930931932933934935936937938939940941942943944945946947948949950951952953954955956957958959960961962963964965966967968969970971972973974975976977978979980981982983984985986987988989990991992993994995996997998999100010011002100310041005100610071008100910101011101210131014101510161017101810191020102110221023102410251026102710281029103010311032103310341035 |
- // SPDX-License-Identifier: GPL-2.0
- /*
- * PCI Peer 2 Peer DMA support.
- *
- * Copyright (c) 2016-2018, Logan Gunthorpe
- * Copyright (c) 2016-2017, Microsemi Corporation
- * Copyright (c) 2017, Christoph Hellwig
- * Copyright (c) 2018, Eideticom Inc.
- */
- #define pr_fmt(fmt) "pci-p2pdma: " fmt
- #include <linux/ctype.h>
- #include <linux/pci-p2pdma.h>
- #include <linux/module.h>
- #include <linux/slab.h>
- #include <linux/genalloc.h>
- #include <linux/memremap.h>
- #include <linux/percpu-refcount.h>
- #include <linux/random.h>
- #include <linux/seq_buf.h>
- #include <linux/xarray.h>
- enum pci_p2pdma_map_type {
- PCI_P2PDMA_MAP_UNKNOWN = 0,
- PCI_P2PDMA_MAP_NOT_SUPPORTED,
- PCI_P2PDMA_MAP_BUS_ADDR,
- PCI_P2PDMA_MAP_THRU_HOST_BRIDGE,
- };
- struct pci_p2pdma {
- struct gen_pool *pool;
- bool p2pmem_published;
- struct xarray map_types;
- };
- struct pci_p2pdma_pagemap {
- struct dev_pagemap pgmap;
- struct pci_dev *provider;
- u64 bus_offset;
- };
- static struct pci_p2pdma_pagemap *to_p2p_pgmap(struct dev_pagemap *pgmap)
- {
- return container_of(pgmap, struct pci_p2pdma_pagemap, pgmap);
- }
- static ssize_t size_show(struct device *dev, struct device_attribute *attr,
- char *buf)
- {
- struct pci_dev *pdev = to_pci_dev(dev);
- size_t size = 0;
- if (pdev->p2pdma->pool)
- size = gen_pool_size(pdev->p2pdma->pool);
- return scnprintf(buf, PAGE_SIZE, "%zd\n", size);
- }
- static DEVICE_ATTR_RO(size);
- static ssize_t available_show(struct device *dev, struct device_attribute *attr,
- char *buf)
- {
- struct pci_dev *pdev = to_pci_dev(dev);
- size_t avail = 0;
- if (pdev->p2pdma->pool)
- avail = gen_pool_avail(pdev->p2pdma->pool);
- return scnprintf(buf, PAGE_SIZE, "%zd\n", avail);
- }
- static DEVICE_ATTR_RO(available);
- static ssize_t published_show(struct device *dev, struct device_attribute *attr,
- char *buf)
- {
- struct pci_dev *pdev = to_pci_dev(dev);
- return scnprintf(buf, PAGE_SIZE, "%d\n",
- pdev->p2pdma->p2pmem_published);
- }
- static DEVICE_ATTR_RO(published);
- static struct attribute *p2pmem_attrs[] = {
- &dev_attr_size.attr,
- &dev_attr_available.attr,
- &dev_attr_published.attr,
- NULL,
- };
- static const struct attribute_group p2pmem_group = {
- .attrs = p2pmem_attrs,
- .name = "p2pmem",
- };
- static void pci_p2pdma_release(void *data)
- {
- struct pci_dev *pdev = data;
- struct pci_p2pdma *p2pdma = pdev->p2pdma;
- if (!p2pdma)
- return;
- /* Flush and disable pci_alloc_p2p_mem() */
- pdev->p2pdma = NULL;
- synchronize_rcu();
- gen_pool_destroy(p2pdma->pool);
- sysfs_remove_group(&pdev->dev.kobj, &p2pmem_group);
- xa_destroy(&p2pdma->map_types);
- }
- static int pci_p2pdma_setup(struct pci_dev *pdev)
- {
- int error = -ENOMEM;
- struct pci_p2pdma *p2p;
- p2p = devm_kzalloc(&pdev->dev, sizeof(*p2p), GFP_KERNEL);
- if (!p2p)
- return -ENOMEM;
- xa_init(&p2p->map_types);
- p2p->pool = gen_pool_create(PAGE_SHIFT, dev_to_node(&pdev->dev));
- if (!p2p->pool)
- goto out;
- error = devm_add_action_or_reset(&pdev->dev, pci_p2pdma_release, pdev);
- if (error)
- goto out_pool_destroy;
- pdev->p2pdma = p2p;
- error = sysfs_create_group(&pdev->dev.kobj, &p2pmem_group);
- if (error)
- goto out_pool_destroy;
- return 0;
- out_pool_destroy:
- pdev->p2pdma = NULL;
- gen_pool_destroy(p2p->pool);
- out:
- devm_kfree(&pdev->dev, p2p);
- return error;
- }
- /**
- * pci_p2pdma_add_resource - add memory for use as p2p memory
- * @pdev: the device to add the memory to
- * @bar: PCI BAR to add
- * @size: size of the memory to add, may be zero to use the whole BAR
- * @offset: offset into the PCI BAR
- *
- * The memory will be given ZONE_DEVICE struct pages so that it may
- * be used with any DMA request.
- */
- int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size,
- u64 offset)
- {
- struct pci_p2pdma_pagemap *p2p_pgmap;
- struct dev_pagemap *pgmap;
- void *addr;
- int error;
- if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM))
- return -EINVAL;
- if (offset >= pci_resource_len(pdev, bar))
- return -EINVAL;
- if (!size)
- size = pci_resource_len(pdev, bar) - offset;
- if (size + offset > pci_resource_len(pdev, bar))
- return -EINVAL;
- if (!pdev->p2pdma) {
- error = pci_p2pdma_setup(pdev);
- if (error)
- return error;
- }
- p2p_pgmap = devm_kzalloc(&pdev->dev, sizeof(*p2p_pgmap), GFP_KERNEL);
- if (!p2p_pgmap)
- return -ENOMEM;
- pgmap = &p2p_pgmap->pgmap;
- pgmap->range.start = pci_resource_start(pdev, bar) + offset;
- pgmap->range.end = pgmap->range.start + size - 1;
- pgmap->nr_range = 1;
- pgmap->type = MEMORY_DEVICE_PCI_P2PDMA;
- p2p_pgmap->provider = pdev;
- p2p_pgmap->bus_offset = pci_bus_address(pdev, bar) -
- pci_resource_start(pdev, bar);
- addr = devm_memremap_pages(&pdev->dev, pgmap);
- if (IS_ERR(addr)) {
- error = PTR_ERR(addr);
- goto pgmap_free;
- }
- error = gen_pool_add_owner(pdev->p2pdma->pool, (unsigned long)addr,
- pci_bus_address(pdev, bar) + offset,
- range_len(&pgmap->range), dev_to_node(&pdev->dev),
- pgmap->ref);
- if (error)
- goto pages_free;
- pci_info(pdev, "added peer-to-peer DMA memory %#llx-%#llx\n",
- pgmap->range.start, pgmap->range.end);
- return 0;
- pages_free:
- devm_memunmap_pages(&pdev->dev, pgmap);
- pgmap_free:
- devm_kfree(&pdev->dev, pgmap);
- return error;
- }
- EXPORT_SYMBOL_GPL(pci_p2pdma_add_resource);
- /*
- * Note this function returns the parent PCI device with a
- * reference taken. It is the caller's responsibility to drop
- * the reference.
- */
- static struct pci_dev *find_parent_pci_dev(struct device *dev)
- {
- struct device *parent;
- dev = get_device(dev);
- while (dev) {
- if (dev_is_pci(dev))
- return to_pci_dev(dev);
- parent = get_device(dev->parent);
- put_device(dev);
- dev = parent;
- }
- return NULL;
- }
- /*
- * Check if a PCI bridge has its ACS redirection bits set to redirect P2P
- * TLPs upstream via ACS. Returns 1 if the packets will be redirected
- * upstream, 0 otherwise.
- */
- static int pci_bridge_has_acs_redir(struct pci_dev *pdev)
- {
- int pos;
- u16 ctrl;
- pos = pdev->acs_cap;
- if (!pos)
- return 0;
- pci_read_config_word(pdev, pos + PCI_ACS_CTRL, &ctrl);
- if (ctrl & (PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_EC))
- return 1;
- return 0;
- }
- static void seq_buf_print_bus_devfn(struct seq_buf *buf, struct pci_dev *pdev)
- {
- if (!buf)
- return;
- seq_buf_printf(buf, "%s;", pci_name(pdev));
- }
- static bool cpu_supports_p2pdma(void)
- {
- #ifdef CONFIG_X86
- struct cpuinfo_x86 *c = &cpu_data(0);
- /* Any AMD CPU whose family ID is Zen or newer supports p2pdma */
- if (c->x86_vendor == X86_VENDOR_AMD && c->x86 >= 0x17)
- return true;
- #endif
- return false;
- }
- static const struct pci_p2pdma_whitelist_entry {
- unsigned short vendor;
- unsigned short device;
- enum {
- REQ_SAME_HOST_BRIDGE = 1 << 0,
- } flags;
- } pci_p2pdma_whitelist[] = {
- /* Intel Xeon E5/Core i7 */
- {PCI_VENDOR_ID_INTEL, 0x3c00, REQ_SAME_HOST_BRIDGE},
- {PCI_VENDOR_ID_INTEL, 0x3c01, REQ_SAME_HOST_BRIDGE},
- /* Intel Xeon E7 v3/Xeon E5 v3/Core i7 */
- {PCI_VENDOR_ID_INTEL, 0x2f00, REQ_SAME_HOST_BRIDGE},
- {PCI_VENDOR_ID_INTEL, 0x2f01, REQ_SAME_HOST_BRIDGE},
- /* Intel SkyLake-E */
- {PCI_VENDOR_ID_INTEL, 0x2030, 0},
- {PCI_VENDOR_ID_INTEL, 0x2031, 0},
- {PCI_VENDOR_ID_INTEL, 0x2032, 0},
- {PCI_VENDOR_ID_INTEL, 0x2033, 0},
- {PCI_VENDOR_ID_INTEL, 0x2020, 0},
- {}
- };
- /*
- * This lookup function tries to find the PCI device corresponding to a given
- * host bridge.
- *
- * It assumes the host bridge device is the first PCI device in the
- * bus->devices list and that the devfn is 00.0. These assumptions should hold
- * for all the devices in the whitelist above.
- *
- * This function is equivalent to pci_get_slot(host->bus, 0), however it does
- * not take the pci_bus_sem lock seeing __host_bridge_whitelist() must not
- * sleep.
- *
- * For this to be safe, the caller should hold a reference to a device on the
- * bridge, which should ensure the host_bridge device will not be freed
- * or removed from the head of the devices list.
- */
- static struct pci_dev *pci_host_bridge_dev(struct pci_host_bridge *host)
- {
- struct pci_dev *root;
- root = list_first_entry_or_null(&host->bus->devices,
- struct pci_dev, bus_list);
- if (!root)
- return NULL;
- if (root->devfn != PCI_DEVFN(0, 0))
- return NULL;
- return root;
- }
- static bool __host_bridge_whitelist(struct pci_host_bridge *host,
- bool same_host_bridge)
- {
- struct pci_dev *root = pci_host_bridge_dev(host);
- const struct pci_p2pdma_whitelist_entry *entry;
- unsigned short vendor, device;
- if (!root)
- return false;
- vendor = root->vendor;
- device = root->device;
- for (entry = pci_p2pdma_whitelist; entry->vendor; entry++) {
- if (vendor != entry->vendor || device != entry->device)
- continue;
- if (entry->flags & REQ_SAME_HOST_BRIDGE && !same_host_bridge)
- return false;
- return true;
- }
- return false;
- }
- /*
- * If we can't find a common upstream bridge take a look at the root
- * complex and compare it to a whitelist of known good hardware.
- */
- static bool host_bridge_whitelist(struct pci_dev *a, struct pci_dev *b)
- {
- struct pci_host_bridge *host_a = pci_find_host_bridge(a->bus);
- struct pci_host_bridge *host_b = pci_find_host_bridge(b->bus);
- if (host_a == host_b)
- return __host_bridge_whitelist(host_a, true);
- if (__host_bridge_whitelist(host_a, false) &&
- __host_bridge_whitelist(host_b, false))
- return true;
- return false;
- }
- static enum pci_p2pdma_map_type
- __upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client,
- int *dist, bool *acs_redirects, struct seq_buf *acs_list)
- {
- struct pci_dev *a = provider, *b = client, *bb;
- int dist_a = 0;
- int dist_b = 0;
- int acs_cnt = 0;
- if (acs_redirects)
- *acs_redirects = false;
- /*
- * Note, we don't need to take references to devices returned by
- * pci_upstream_bridge() seeing we hold a reference to a child
- * device which will already hold a reference to the upstream bridge.
- */
- while (a) {
- dist_b = 0;
- if (pci_bridge_has_acs_redir(a)) {
- seq_buf_print_bus_devfn(acs_list, a);
- acs_cnt++;
- }
- bb = b;
- while (bb) {
- if (a == bb)
- goto check_b_path_acs;
- bb = pci_upstream_bridge(bb);
- dist_b++;
- }
- a = pci_upstream_bridge(a);
- dist_a++;
- }
- if (dist)
- *dist = dist_a + dist_b;
- return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE;
- check_b_path_acs:
- bb = b;
- while (bb) {
- if (a == bb)
- break;
- if (pci_bridge_has_acs_redir(bb)) {
- seq_buf_print_bus_devfn(acs_list, bb);
- acs_cnt++;
- }
- bb = pci_upstream_bridge(bb);
- }
- if (dist)
- *dist = dist_a + dist_b;
- if (acs_cnt) {
- if (acs_redirects)
- *acs_redirects = true;
- return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE;
- }
- return PCI_P2PDMA_MAP_BUS_ADDR;
- }
- static unsigned long map_types_idx(struct pci_dev *client)
- {
- return (pci_domain_nr(client->bus) << 16) |
- (client->bus->number << 8) | client->devfn;
- }
- /*
- * Find the distance through the nearest common upstream bridge between
- * two PCI devices.
- *
- * If the two devices are the same device then 0 will be returned.
- *
- * If there are two virtual functions of the same device behind the same
- * bridge port then 2 will be returned (one step down to the PCIe switch,
- * then one step back to the same device).
- *
- * In the case where two devices are connected to the same PCIe switch, the
- * value 4 will be returned. This corresponds to the following PCI tree:
- *
- * -+ Root Port
- * \+ Switch Upstream Port
- * +-+ Switch Downstream Port
- * + \- Device A
- * \-+ Switch Downstream Port
- * \- Device B
- *
- * The distance is 4 because we traverse from Device A through the downstream
- * port of the switch, to the common upstream port, back up to the second
- * downstream port and then to Device B.
- *
- * Any two devices that cannot communicate using p2pdma will return
- * PCI_P2PDMA_MAP_NOT_SUPPORTED.
- *
- * Any two devices that have a data path that goes through the host bridge
- * will consult a whitelist. If the host bridges are on the whitelist,
- * this function will return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE.
- *
- * If either bridge is not on the whitelist this function returns
- * PCI_P2PDMA_MAP_NOT_SUPPORTED.
- *
- * If a bridge which has any ACS redirection bits set is in the path,
- * acs_redirects will be set to true. In this case, a list of all infringing
- * bridge addresses will be populated in acs_list (assuming it's non-null)
- * for printk purposes.
- */
- static enum pci_p2pdma_map_type
- upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client,
- int *dist, bool *acs_redirects, struct seq_buf *acs_list)
- {
- enum pci_p2pdma_map_type map_type;
- map_type = __upstream_bridge_distance(provider, client, dist,
- acs_redirects, acs_list);
- if (map_type == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE) {
- if (!cpu_supports_p2pdma() &&
- !host_bridge_whitelist(provider, client))
- map_type = PCI_P2PDMA_MAP_NOT_SUPPORTED;
- }
- if (provider->p2pdma)
- xa_store(&provider->p2pdma->map_types, map_types_idx(client),
- xa_mk_value(map_type), GFP_KERNEL);
- return map_type;
- }
- static enum pci_p2pdma_map_type
- upstream_bridge_distance_warn(struct pci_dev *provider, struct pci_dev *client,
- int *dist)
- {
- struct seq_buf acs_list;
- bool acs_redirects;
- int ret;
- seq_buf_init(&acs_list, kmalloc(PAGE_SIZE, GFP_KERNEL), PAGE_SIZE);
- if (!acs_list.buffer)
- return -ENOMEM;
- ret = upstream_bridge_distance(provider, client, dist, &acs_redirects,
- &acs_list);
- if (acs_redirects) {
- pci_warn(client, "ACS redirect is set between the client and provider (%s)\n",
- pci_name(provider));
- /* Drop final semicolon */
- acs_list.buffer[acs_list.len-1] = 0;
- 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
- * 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, otherwise returns a
- * 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).
- *
- * "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++) {
- #ifdef CONFIG_DMA_VIRT_OPS
- if (clients[i]->dma_ops == &dma_virt_ops) {
- if (verbose)
- dev_warn(clients[i],
- "cannot be used for peer-to-peer DMA because the driver makes use of dma_virt_ops\n");
- return -1;
- }
- #endif
- 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 - 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_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 = 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_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;
- 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_distance_many()
- */
- #ifdef CONFIG_DMA_VIRT_OPS
- if (WARN_ON_ONCE(dev->dma_ops == &dma_virt_ops))
- return 0;
- #endif
- for_each_sg(sg, s, nents, i) {
- paddr = sg_phys(s);
- s->dma_address = paddr - p2p_pgmap->bus_offset;
- sg_dma_len(s) = s->length;
- }
- return nents;
- }
- /**
- * 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
- * @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 - 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);
|