diff options
Diffstat (limited to 'drivers/pci/pcie/ptm.c')
| -rw-r--r-- | drivers/pci/pcie/ptm.c | 579 |
1 files changed, 579 insertions, 0 deletions
diff --git a/drivers/pci/pcie/ptm.c b/drivers/pci/pcie/ptm.c new file mode 100644 index 000000000000..ed0f9691e7d1 --- /dev/null +++ b/drivers/pci/pcie/ptm.c @@ -0,0 +1,579 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * PCI Express Precision Time Measurement + * Copyright (c) 2016, Intel Corporation. + */ + +#include <linux/bitfield.h> +#include <linux/debugfs.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/pci.h> +#include "../pci.h" + +/* + * If the next upstream device supports PTM, return it; otherwise return + * NULL. PTM Messages are local, so both link partners must support it. + */ +static struct pci_dev *pci_upstream_ptm(struct pci_dev *dev) +{ + struct pci_dev *ups = pci_upstream_bridge(dev); + + /* + * Switch Downstream Ports are not permitted to have a PTM + * capability; their PTM behavior is controlled by the Upstream + * Port (PCIe r5.0, sec 7.9.16), so if the upstream bridge is a + * Switch Downstream Port, look up one more level. + */ + if (ups && pci_pcie_type(ups) == PCI_EXP_TYPE_DOWNSTREAM) + ups = pci_upstream_bridge(ups); + + if (ups && ups->ptm_cap) + return ups; + + return NULL; +} + +/* + * Find the PTM Capability (if present) and extract the information we need + * to use it. + */ +void pci_ptm_init(struct pci_dev *dev) +{ + u16 ptm; + u32 cap; + struct pci_dev *ups; + + if (!pci_is_pcie(dev)) + return; + + ptm = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM); + if (!ptm) + return; + + dev->ptm_cap = ptm; + pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_PTM, sizeof(u32)); + + pci_read_config_dword(dev, ptm + PCI_PTM_CAP, &cap); + dev->ptm_granularity = FIELD_GET(PCI_PTM_GRANULARITY_MASK, cap); + + /* + * Per the spec recommendation (PCIe r6.0, sec 7.9.15.3), select the + * furthest upstream Time Source as the PTM Root. For Endpoints, + * "the Effective Granularity is the maximum Local Clock Granularity + * reported by the PTM Root and all intervening PTM Time Sources." + */ + ups = pci_upstream_ptm(dev); + if (ups) { + if (ups->ptm_granularity == 0) + dev->ptm_granularity = 0; + else if (ups->ptm_granularity > dev->ptm_granularity) + dev->ptm_granularity = ups->ptm_granularity; + } else if (cap & PCI_PTM_CAP_ROOT) { + dev->ptm_root = 1; + } else if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) { + + /* + * Per sec 7.9.15.3, this should be the Local Clock + * Granularity of the associated Time Source. But it + * doesn't say how to find that Time Source. + */ + dev->ptm_granularity = 0; + } + + if (cap & PCI_PTM_CAP_RES) + dev->ptm_responder = 1; + if (cap & PCI_PTM_CAP_REQ) + dev->ptm_requester = 1; + + if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT || + pci_pcie_type(dev) == PCI_EXP_TYPE_UPSTREAM) + pci_enable_ptm(dev, NULL); +} + +void pci_save_ptm_state(struct pci_dev *dev) +{ + u16 ptm = dev->ptm_cap; + struct pci_cap_saved_state *save_state; + u32 *cap; + + if (!ptm) + return; + + save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_PTM); + if (!save_state) + return; + + cap = (u32 *)&save_state->cap.data[0]; + pci_read_config_dword(dev, ptm + PCI_PTM_CTRL, cap); +} + +void pci_restore_ptm_state(struct pci_dev *dev) +{ + u16 ptm = dev->ptm_cap; + struct pci_cap_saved_state *save_state; + u32 *cap; + + if (!ptm) + return; + + save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_PTM); + if (!save_state) + return; + + cap = (u32 *)&save_state->cap.data[0]; + pci_write_config_dword(dev, ptm + PCI_PTM_CTRL, *cap); +} + +/* Enable PTM in the Control register if possible */ +static int __pci_enable_ptm(struct pci_dev *dev) +{ + u16 ptm = dev->ptm_cap; + struct pci_dev *ups; + u32 ctrl; + + if (!ptm) + return -EINVAL; + + /* + * A device uses local PTM Messages to request time information + * from a PTM Root that's farther upstream. Every device along the + * path must support PTM and have it enabled so it can handle the + * messages. Therefore, if this device is not a PTM Root, the + * upstream link partner must have PTM enabled before we can enable + * PTM. + */ + if (!dev->ptm_root) { + ups = pci_upstream_ptm(dev); + if (!ups || !ups->ptm_enabled) + return -EINVAL; + } + + switch (pci_pcie_type(dev)) { + case PCI_EXP_TYPE_ROOT_PORT: + if (!dev->ptm_root) + return -EINVAL; + break; + case PCI_EXP_TYPE_UPSTREAM: + if (!dev->ptm_responder) + return -EINVAL; + break; + case PCI_EXP_TYPE_ENDPOINT: + case PCI_EXP_TYPE_LEG_END: + if (!dev->ptm_requester) + return -EINVAL; + break; + default: + return -EINVAL; + } + + pci_read_config_dword(dev, ptm + PCI_PTM_CTRL, &ctrl); + + ctrl |= PCI_PTM_CTRL_ENABLE; + ctrl &= ~PCI_PTM_GRANULARITY_MASK; + ctrl |= FIELD_PREP(PCI_PTM_GRANULARITY_MASK, dev->ptm_granularity); + if (dev->ptm_root) + ctrl |= PCI_PTM_CTRL_ROOT; + + pci_write_config_dword(dev, ptm + PCI_PTM_CTRL, ctrl); + return 0; +} + +/** + * pci_enable_ptm() - Enable Precision Time Measurement + * @dev: PCI device + * @granularity: pointer to return granularity + * + * Enable Precision Time Measurement for @dev. If successful and + * @granularity is non-NULL, return the Effective Granularity. + * + * Return: zero if successful, or -EINVAL if @dev lacks a PTM Capability or + * is not a PTM Root and lacks an upstream path of PTM-enabled devices. + */ +int pci_enable_ptm(struct pci_dev *dev, u8 *granularity) +{ + int rc; + char clock_desc[8]; + + rc = __pci_enable_ptm(dev); + if (rc) + return rc; + + dev->ptm_enabled = 1; + + if (granularity) + *granularity = dev->ptm_granularity; + + switch (dev->ptm_granularity) { + case 0: + snprintf(clock_desc, sizeof(clock_desc), "unknown"); + break; + case 255: + snprintf(clock_desc, sizeof(clock_desc), ">254ns"); + break; + default: + snprintf(clock_desc, sizeof(clock_desc), "%uns", + dev->ptm_granularity); + break; + } + pci_info(dev, "PTM enabled%s, %s granularity\n", + dev->ptm_root ? " (root)" : "", clock_desc); + + return 0; +} +EXPORT_SYMBOL(pci_enable_ptm); + +static void __pci_disable_ptm(struct pci_dev *dev) +{ + u16 ptm = dev->ptm_cap; + u32 ctrl; + + if (!ptm) + return; + + pci_read_config_dword(dev, ptm + PCI_PTM_CTRL, &ctrl); + ctrl &= ~(PCI_PTM_CTRL_ENABLE | PCI_PTM_CTRL_ROOT); + pci_write_config_dword(dev, ptm + PCI_PTM_CTRL, ctrl); +} + +/** + * pci_disable_ptm() - Disable Precision Time Measurement + * @dev: PCI device + * + * Disable Precision Time Measurement for @dev. + */ +void pci_disable_ptm(struct pci_dev *dev) +{ + if (dev->ptm_enabled) { + __pci_disable_ptm(dev); + dev->ptm_enabled = 0; + } +} +EXPORT_SYMBOL(pci_disable_ptm); + +/* + * Disable PTM, but preserve dev->ptm_enabled so we silently re-enable it on + * resume if necessary. + */ +void pci_suspend_ptm(struct pci_dev *dev) +{ + if (dev->ptm_enabled) + __pci_disable_ptm(dev); +} + +/* If PTM was enabled before suspend, re-enable it when resuming */ +void pci_resume_ptm(struct pci_dev *dev) +{ + if (dev->ptm_enabled) + __pci_enable_ptm(dev); +} + +bool pcie_ptm_enabled(struct pci_dev *dev) +{ + if (!dev) + return false; + + return dev->ptm_enabled; +} +EXPORT_SYMBOL(pcie_ptm_enabled); + +#if IS_ENABLED(CONFIG_DEBUG_FS) +static ssize_t context_update_write(struct file *file, const char __user *ubuf, + size_t count, loff_t *ppos) +{ + struct pci_ptm_debugfs *ptm_debugfs = file->private_data; + char buf[7]; + int ret; + u8 mode; + + if (!ptm_debugfs->ops->context_update_write) + return -EOPNOTSUPP; + + if (count < 1 || count >= sizeof(buf)) + return -EINVAL; + + ret = copy_from_user(buf, ubuf, count); + if (ret) + return -EFAULT; + + buf[count] = '\0'; + + if (sysfs_streq(buf, "auto")) + mode = PCIE_PTM_CONTEXT_UPDATE_AUTO; + else if (sysfs_streq(buf, "manual")) + mode = PCIE_PTM_CONTEXT_UPDATE_MANUAL; + else + return -EINVAL; + + mutex_lock(&ptm_debugfs->lock); + ret = ptm_debugfs->ops->context_update_write(ptm_debugfs->pdata, mode); + mutex_unlock(&ptm_debugfs->lock); + if (ret) + return ret; + + return count; +} + +static ssize_t context_update_read(struct file *file, char __user *ubuf, + size_t count, loff_t *ppos) +{ + struct pci_ptm_debugfs *ptm_debugfs = file->private_data; + char buf[8]; /* Extra space for NULL termination at the end */ + ssize_t pos; + u8 mode; + + if (!ptm_debugfs->ops->context_update_read) + return -EOPNOTSUPP; + + mutex_lock(&ptm_debugfs->lock); + ptm_debugfs->ops->context_update_read(ptm_debugfs->pdata, &mode); + mutex_unlock(&ptm_debugfs->lock); + + if (mode == PCIE_PTM_CONTEXT_UPDATE_AUTO) + pos = scnprintf(buf, sizeof(buf), "auto\n"); + else + pos = scnprintf(buf, sizeof(buf), "manual\n"); + + return simple_read_from_buffer(ubuf, count, ppos, buf, pos); +} + +static const struct file_operations context_update_fops = { + .open = simple_open, + .read = context_update_read, + .write = context_update_write, +}; + +static int context_valid_get(void *data, u64 *val) +{ + struct pci_ptm_debugfs *ptm_debugfs = data; + bool valid; + int ret; + + if (!ptm_debugfs->ops->context_valid_read) + return -EOPNOTSUPP; + + mutex_lock(&ptm_debugfs->lock); + ret = ptm_debugfs->ops->context_valid_read(ptm_debugfs->pdata, &valid); + mutex_unlock(&ptm_debugfs->lock); + if (ret) + return ret; + + *val = valid; + + return 0; +} + +static int context_valid_set(void *data, u64 val) +{ + struct pci_ptm_debugfs *ptm_debugfs = data; + int ret; + + if (!ptm_debugfs->ops->context_valid_write) + return -EOPNOTSUPP; + + mutex_lock(&ptm_debugfs->lock); + ret = ptm_debugfs->ops->context_valid_write(ptm_debugfs->pdata, !!val); + mutex_unlock(&ptm_debugfs->lock); + + return ret; +} + +DEFINE_DEBUGFS_ATTRIBUTE(context_valid_fops, context_valid_get, + context_valid_set, "%llu\n"); + +static int local_clock_get(void *data, u64 *val) +{ + struct pci_ptm_debugfs *ptm_debugfs = data; + u64 clock; + int ret; + + if (!ptm_debugfs->ops->local_clock_read) + return -EOPNOTSUPP; + + ret = ptm_debugfs->ops->local_clock_read(ptm_debugfs->pdata, &clock); + if (ret) + return ret; + + *val = clock; + + return 0; +} + +DEFINE_DEBUGFS_ATTRIBUTE(local_clock_fops, local_clock_get, NULL, "%llu\n"); + +static int master_clock_get(void *data, u64 *val) +{ + struct pci_ptm_debugfs *ptm_debugfs = data; + u64 clock; + int ret; + + if (!ptm_debugfs->ops->master_clock_read) + return -EOPNOTSUPP; + + ret = ptm_debugfs->ops->master_clock_read(ptm_debugfs->pdata, &clock); + if (ret) + return ret; + + *val = clock; + + return 0; +} + +DEFINE_DEBUGFS_ATTRIBUTE(master_clock_fops, master_clock_get, NULL, "%llu\n"); + +static int t1_get(void *data, u64 *val) +{ + struct pci_ptm_debugfs *ptm_debugfs = data; + u64 clock; + int ret; + + if (!ptm_debugfs->ops->t1_read) + return -EOPNOTSUPP; + + ret = ptm_debugfs->ops->t1_read(ptm_debugfs->pdata, &clock); + if (ret) + return ret; + + *val = clock; + + return 0; +} + +DEFINE_DEBUGFS_ATTRIBUTE(t1_fops, t1_get, NULL, "%llu\n"); + +static int t2_get(void *data, u64 *val) +{ + struct pci_ptm_debugfs *ptm_debugfs = data; + u64 clock; + int ret; + + if (!ptm_debugfs->ops->t2_read) + return -EOPNOTSUPP; + + ret = ptm_debugfs->ops->t2_read(ptm_debugfs->pdata, &clock); + if (ret) + return ret; + + *val = clock; + + return 0; +} + +DEFINE_DEBUGFS_ATTRIBUTE(t2_fops, t2_get, NULL, "%llu\n"); + +static int t3_get(void *data, u64 *val) +{ + struct pci_ptm_debugfs *ptm_debugfs = data; + u64 clock; + int ret; + + if (!ptm_debugfs->ops->t3_read) + return -EOPNOTSUPP; + + ret = ptm_debugfs->ops->t3_read(ptm_debugfs->pdata, &clock); + if (ret) + return ret; + + *val = clock; + + return 0; +} + +DEFINE_DEBUGFS_ATTRIBUTE(t3_fops, t3_get, NULL, "%llu\n"); + +static int t4_get(void *data, u64 *val) +{ + struct pci_ptm_debugfs *ptm_debugfs = data; + u64 clock; + int ret; + + if (!ptm_debugfs->ops->t4_read) + return -EOPNOTSUPP; + + ret = ptm_debugfs->ops->t4_read(ptm_debugfs->pdata, &clock); + if (ret) + return ret; + + *val = clock; + + return 0; +} + +DEFINE_DEBUGFS_ATTRIBUTE(t4_fops, t4_get, NULL, "%llu\n"); + +#define pcie_ptm_create_debugfs_file(pdata, mode, attr) \ + do { \ + if (ops->attr##_visible && ops->attr##_visible(pdata)) \ + debugfs_create_file(#attr, mode, ptm_debugfs->debugfs, \ + ptm_debugfs, &attr##_fops); \ + } while (0) + +/* + * pcie_ptm_create_debugfs() - Create debugfs entries for the PTM context + * @dev: PTM capable component device + * @pdata: Private data of the PTM capable component device + * @ops: PTM callback structure + * + * Create debugfs entries for exposing the PTM context of the PTM capable + * components such as Root Complex and Endpoint controllers. + * + * Return: Pointer to 'struct pci_ptm_debugfs' if success, NULL otherwise. + */ +struct pci_ptm_debugfs *pcie_ptm_create_debugfs(struct device *dev, void *pdata, + const struct pcie_ptm_ops *ops) +{ + struct pci_ptm_debugfs *ptm_debugfs; + char *dirname; + int ret; + + /* Caller must provide check_capability() callback */ + if (!ops->check_capability) + return NULL; + + /* Check for PTM capability before creating debugfs attributes */ + ret = ops->check_capability(pdata); + if (!ret) { + dev_dbg(dev, "PTM capability not present\n"); + return NULL; + } + + ptm_debugfs = kzalloc(sizeof(*ptm_debugfs), GFP_KERNEL); + if (!ptm_debugfs) + return NULL; + + dirname = devm_kasprintf(dev, GFP_KERNEL, "pcie_ptm_%s", dev_name(dev)); + if (!dirname) + return NULL; + + ptm_debugfs->debugfs = debugfs_create_dir(dirname, NULL); + ptm_debugfs->pdata = pdata; + ptm_debugfs->ops = ops; + mutex_init(&ptm_debugfs->lock); + + pcie_ptm_create_debugfs_file(pdata, 0644, context_update); + pcie_ptm_create_debugfs_file(pdata, 0644, context_valid); + pcie_ptm_create_debugfs_file(pdata, 0444, local_clock); + pcie_ptm_create_debugfs_file(pdata, 0444, master_clock); + pcie_ptm_create_debugfs_file(pdata, 0444, t1); + pcie_ptm_create_debugfs_file(pdata, 0444, t2); + pcie_ptm_create_debugfs_file(pdata, 0444, t3); + pcie_ptm_create_debugfs_file(pdata, 0444, t4); + + return ptm_debugfs; +} +EXPORT_SYMBOL_GPL(pcie_ptm_create_debugfs); + +/* + * pcie_ptm_destroy_debugfs() - Destroy debugfs entries for the PTM context + * @ptm_debugfs: Pointer to the PTM debugfs struct + */ +void pcie_ptm_destroy_debugfs(struct pci_ptm_debugfs *ptm_debugfs) +{ + if (!ptm_debugfs) + return; + + mutex_destroy(&ptm_debugfs->lock); + debugfs_remove_recursive(ptm_debugfs->debugfs); +} +EXPORT_SYMBOL_GPL(pcie_ptm_destroy_debugfs); +#endif |