| // 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 snprintf(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 snprintf(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 snprintf(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}, |
| {} |
| }; |
| |
| static bool __host_bridge_whitelist(struct pci_host_bridge *host, |
| bool same_host_bridge) |
| { |
| struct pci_dev *root = pci_get_slot(host->bus, PCI_DEVFN(0, 0)); |
| const struct pci_p2pdma_whitelist_entry *entry; |
| unsigned short vendor, device; |
| |
| if (!root) |
| return false; |
| |
| vendor = root->vendor; |
| device = root->device; |
| pci_dev_put(root); |
| |
| 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 = 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 |
| * 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); |