diff options
Diffstat (limited to 'drivers/pci/doe.c')
| -rw-r--r-- | drivers/pci/doe.c | 724 |
1 files changed, 724 insertions, 0 deletions
diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c new file mode 100644 index 0000000000..e3aab5edaf --- /dev/null +++ b/drivers/pci/doe.c @@ -0,0 +1,724 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Data Object Exchange + * PCIe r6.0, sec 6.30 DOE + * + * Copyright (C) 2021 Huawei + * Jonathan Cameron <Jonathan.Cameron@huawei.com> + * + * Copyright (C) 2022 Intel Corporation + * Ira Weiny <ira.weiny@intel.com> + */ + +#define dev_fmt(fmt) "DOE: " fmt + +#include <linux/bitfield.h> +#include <linux/delay.h> +#include <linux/jiffies.h> +#include <linux/mutex.h> +#include <linux/pci.h> +#include <linux/pci-doe.h> +#include <linux/workqueue.h> + +#include "pci.h" + +#define PCI_DOE_PROTOCOL_DISCOVERY 0 + +/* Timeout of 1 second from 6.30.2 Operation, PCI Spec r6.0 */ +#define PCI_DOE_TIMEOUT HZ +#define PCI_DOE_POLL_INTERVAL (PCI_DOE_TIMEOUT / 128) + +#define PCI_DOE_FLAG_CANCEL 0 +#define PCI_DOE_FLAG_DEAD 1 + +/* Max data object length is 2^18 dwords */ +#define PCI_DOE_MAX_LENGTH (1 << 18) + +/** + * struct pci_doe_mb - State for a single DOE mailbox + * + * This state is used to manage a single DOE mailbox capability. All fields + * should be considered opaque to the consumers and the structure passed into + * the helpers below after being created by pci_doe_create_mb(). + * + * @pdev: PCI device this mailbox belongs to + * @cap_offset: Capability offset + * @prots: Array of protocols supported (encoded as long values) + * @wq: Wait queue for work item + * @work_queue: Queue of pci_doe_work items + * @flags: Bit array of PCI_DOE_FLAG_* flags + */ +struct pci_doe_mb { + struct pci_dev *pdev; + u16 cap_offset; + struct xarray prots; + + wait_queue_head_t wq; + struct workqueue_struct *work_queue; + unsigned long flags; +}; + +struct pci_doe_protocol { + u16 vid; + u8 type; +}; + +/** + * struct pci_doe_task - represents a single query/response + * + * @prot: DOE Protocol + * @request_pl: The request payload + * @request_pl_sz: Size of the request payload (bytes) + * @response_pl: The response payload + * @response_pl_sz: Size of the response payload (bytes) + * @rv: Return value. Length of received response or error (bytes) + * @complete: Called when task is complete + * @private: Private data for the consumer + * @work: Used internally by the mailbox + * @doe_mb: Used internally by the mailbox + */ +struct pci_doe_task { + struct pci_doe_protocol prot; + const __le32 *request_pl; + size_t request_pl_sz; + __le32 *response_pl; + size_t response_pl_sz; + int rv; + void (*complete)(struct pci_doe_task *task); + void *private; + + /* initialized by pci_doe_submit_task() */ + struct work_struct work; + struct pci_doe_mb *doe_mb; +}; + +static int pci_doe_wait(struct pci_doe_mb *doe_mb, unsigned long timeout) +{ + if (wait_event_timeout(doe_mb->wq, + test_bit(PCI_DOE_FLAG_CANCEL, &doe_mb->flags), + timeout)) + return -EIO; + return 0; +} + +static void pci_doe_write_ctrl(struct pci_doe_mb *doe_mb, u32 val) +{ + struct pci_dev *pdev = doe_mb->pdev; + int offset = doe_mb->cap_offset; + + pci_write_config_dword(pdev, offset + PCI_DOE_CTRL, val); +} + +static int pci_doe_abort(struct pci_doe_mb *doe_mb) +{ + struct pci_dev *pdev = doe_mb->pdev; + int offset = doe_mb->cap_offset; + unsigned long timeout_jiffies; + + pci_dbg(pdev, "[%x] Issuing Abort\n", offset); + + timeout_jiffies = jiffies + PCI_DOE_TIMEOUT; + pci_doe_write_ctrl(doe_mb, PCI_DOE_CTRL_ABORT); + + do { + int rc; + u32 val; + + rc = pci_doe_wait(doe_mb, PCI_DOE_POLL_INTERVAL); + if (rc) + return rc; + pci_read_config_dword(pdev, offset + PCI_DOE_STATUS, &val); + + /* Abort success! */ + if (!FIELD_GET(PCI_DOE_STATUS_ERROR, val) && + !FIELD_GET(PCI_DOE_STATUS_BUSY, val)) + return 0; + + } while (!time_after(jiffies, timeout_jiffies)); + + /* Abort has timed out and the MB is dead */ + pci_err(pdev, "[%x] ABORT timed out\n", offset); + return -EIO; +} + +static int pci_doe_send_req(struct pci_doe_mb *doe_mb, + struct pci_doe_task *task) +{ + struct pci_dev *pdev = doe_mb->pdev; + int offset = doe_mb->cap_offset; + size_t length, remainder; + u32 val; + int i; + + /* + * Check the DOE busy bit is not set. If it is set, this could indicate + * someone other than Linux (e.g. firmware) is using the mailbox. Note + * it is expected that firmware and OS will negotiate access rights via + * an, as yet to be defined, method. + */ + pci_read_config_dword(pdev, offset + PCI_DOE_STATUS, &val); + if (FIELD_GET(PCI_DOE_STATUS_BUSY, val)) + return -EBUSY; + + if (FIELD_GET(PCI_DOE_STATUS_ERROR, val)) + return -EIO; + + /* Length is 2 DW of header + length of payload in DW */ + length = 2 + DIV_ROUND_UP(task->request_pl_sz, sizeof(__le32)); + if (length > PCI_DOE_MAX_LENGTH) + return -EIO; + if (length == PCI_DOE_MAX_LENGTH) + length = 0; + + /* Write DOE Header */ + val = FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_1_VID, task->prot.vid) | + FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_1_TYPE, task->prot.type); + pci_write_config_dword(pdev, offset + PCI_DOE_WRITE, val); + pci_write_config_dword(pdev, offset + PCI_DOE_WRITE, + FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_2_LENGTH, + length)); + + /* Write payload */ + for (i = 0; i < task->request_pl_sz / sizeof(__le32); i++) + pci_write_config_dword(pdev, offset + PCI_DOE_WRITE, + le32_to_cpu(task->request_pl[i])); + + /* Write last payload dword */ + remainder = task->request_pl_sz % sizeof(__le32); + if (remainder) { + val = 0; + memcpy(&val, &task->request_pl[i], remainder); + le32_to_cpus(&val); + pci_write_config_dword(pdev, offset + PCI_DOE_WRITE, val); + } + + pci_doe_write_ctrl(doe_mb, PCI_DOE_CTRL_GO); + + return 0; +} + +static bool pci_doe_data_obj_ready(struct pci_doe_mb *doe_mb) +{ + struct pci_dev *pdev = doe_mb->pdev; + int offset = doe_mb->cap_offset; + u32 val; + + pci_read_config_dword(pdev, offset + PCI_DOE_STATUS, &val); + if (FIELD_GET(PCI_DOE_STATUS_DATA_OBJECT_READY, val)) + return true; + return false; +} + +static int pci_doe_recv_resp(struct pci_doe_mb *doe_mb, struct pci_doe_task *task) +{ + size_t length, payload_length, remainder, received; + struct pci_dev *pdev = doe_mb->pdev; + int offset = doe_mb->cap_offset; + int i = 0; + u32 val; + + /* Read the first dword to get the protocol */ + pci_read_config_dword(pdev, offset + PCI_DOE_READ, &val); + if ((FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_VID, val) != task->prot.vid) || + (FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_TYPE, val) != task->prot.type)) { + dev_err_ratelimited(&pdev->dev, "[%x] expected [VID, Protocol] = [%04x, %02x], got [%04x, %02x]\n", + doe_mb->cap_offset, task->prot.vid, task->prot.type, + FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_VID, val), + FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_TYPE, val)); + return -EIO; + } + + pci_write_config_dword(pdev, offset + PCI_DOE_READ, 0); + /* Read the second dword to get the length */ + pci_read_config_dword(pdev, offset + PCI_DOE_READ, &val); + pci_write_config_dword(pdev, offset + PCI_DOE_READ, 0); + + length = FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_2_LENGTH, val); + /* A value of 0x0 indicates max data object length */ + if (!length) + length = PCI_DOE_MAX_LENGTH; + if (length < 2) + return -EIO; + + /* First 2 dwords have already been read */ + length -= 2; + received = task->response_pl_sz; + payload_length = DIV_ROUND_UP(task->response_pl_sz, sizeof(__le32)); + remainder = task->response_pl_sz % sizeof(__le32); + + /* remainder signifies number of data bytes in last payload dword */ + if (!remainder) + remainder = sizeof(__le32); + + if (length < payload_length) { + received = length * sizeof(__le32); + payload_length = length; + remainder = sizeof(__le32); + } + + if (payload_length) { + /* Read all payload dwords except the last */ + for (; i < payload_length - 1; i++) { + pci_read_config_dword(pdev, offset + PCI_DOE_READ, + &val); + task->response_pl[i] = cpu_to_le32(val); + pci_write_config_dword(pdev, offset + PCI_DOE_READ, 0); + } + + /* Read last payload dword */ + pci_read_config_dword(pdev, offset + PCI_DOE_READ, &val); + cpu_to_le32s(&val); + memcpy(&task->response_pl[i], &val, remainder); + /* Prior to the last ack, ensure Data Object Ready */ + if (!pci_doe_data_obj_ready(doe_mb)) + return -EIO; + pci_write_config_dword(pdev, offset + PCI_DOE_READ, 0); + i++; + } + + /* Flush excess length */ + for (; i < length; i++) { + pci_read_config_dword(pdev, offset + PCI_DOE_READ, &val); + pci_write_config_dword(pdev, offset + PCI_DOE_READ, 0); + } + + /* Final error check to pick up on any since Data Object Ready */ + pci_read_config_dword(pdev, offset + PCI_DOE_STATUS, &val); + if (FIELD_GET(PCI_DOE_STATUS_ERROR, val)) + return -EIO; + + return received; +} + +static void signal_task_complete(struct pci_doe_task *task, int rv) +{ + task->rv = rv; + destroy_work_on_stack(&task->work); + task->complete(task); +} + +static void signal_task_abort(struct pci_doe_task *task, int rv) +{ + struct pci_doe_mb *doe_mb = task->doe_mb; + struct pci_dev *pdev = doe_mb->pdev; + + if (pci_doe_abort(doe_mb)) { + /* + * If the device can't process an abort; set the mailbox dead + * - no more submissions + */ + pci_err(pdev, "[%x] Abort failed marking mailbox dead\n", + doe_mb->cap_offset); + set_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags); + } + signal_task_complete(task, rv); +} + +static void doe_statemachine_work(struct work_struct *work) +{ + struct pci_doe_task *task = container_of(work, struct pci_doe_task, + work); + struct pci_doe_mb *doe_mb = task->doe_mb; + struct pci_dev *pdev = doe_mb->pdev; + int offset = doe_mb->cap_offset; + unsigned long timeout_jiffies; + u32 val; + int rc; + + if (test_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags)) { + signal_task_complete(task, -EIO); + return; + } + + /* Send request */ + rc = pci_doe_send_req(doe_mb, task); + if (rc) { + /* + * The specification does not provide any guidance on how to + * resolve conflicting requests from other entities. + * Furthermore, it is likely that busy will not be detected + * most of the time. Flag any detection of status busy with an + * error. + */ + if (rc == -EBUSY) + dev_err_ratelimited(&pdev->dev, "[%x] busy detected; another entity is sending conflicting requests\n", + offset); + signal_task_abort(task, rc); + return; + } + + timeout_jiffies = jiffies + PCI_DOE_TIMEOUT; + /* Poll for response */ +retry_resp: + pci_read_config_dword(pdev, offset + PCI_DOE_STATUS, &val); + if (FIELD_GET(PCI_DOE_STATUS_ERROR, val)) { + signal_task_abort(task, -EIO); + return; + } + + if (!FIELD_GET(PCI_DOE_STATUS_DATA_OBJECT_READY, val)) { + if (time_after(jiffies, timeout_jiffies)) { + signal_task_abort(task, -EIO); + return; + } + rc = pci_doe_wait(doe_mb, PCI_DOE_POLL_INTERVAL); + if (rc) { + signal_task_abort(task, rc); + return; + } + goto retry_resp; + } + + rc = pci_doe_recv_resp(doe_mb, task); + if (rc < 0) { + signal_task_abort(task, rc); + return; + } + + signal_task_complete(task, rc); +} + +static void pci_doe_task_complete(struct pci_doe_task *task) +{ + complete(task->private); +} + +static int pci_doe_discovery(struct pci_doe_mb *doe_mb, u8 *index, u16 *vid, + u8 *protocol) +{ + u32 request_pl = FIELD_PREP(PCI_DOE_DATA_OBJECT_DISC_REQ_3_INDEX, + *index); + __le32 request_pl_le = cpu_to_le32(request_pl); + __le32 response_pl_le; + u32 response_pl; + int rc; + + rc = pci_doe(doe_mb, PCI_VENDOR_ID_PCI_SIG, PCI_DOE_PROTOCOL_DISCOVERY, + &request_pl_le, sizeof(request_pl_le), + &response_pl_le, sizeof(response_pl_le)); + if (rc < 0) + return rc; + + if (rc != sizeof(response_pl_le)) + return -EIO; + + response_pl = le32_to_cpu(response_pl_le); + *vid = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_VID, response_pl); + *protocol = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_PROTOCOL, + response_pl); + *index = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_NEXT_INDEX, + response_pl); + + return 0; +} + +static void *pci_doe_xa_prot_entry(u16 vid, u8 prot) +{ + return xa_mk_value((vid << 8) | prot); +} + +static int pci_doe_cache_protocols(struct pci_doe_mb *doe_mb) +{ + u8 index = 0; + u8 xa_idx = 0; + + do { + int rc; + u16 vid; + u8 prot; + + rc = pci_doe_discovery(doe_mb, &index, &vid, &prot); + if (rc) + return rc; + + pci_dbg(doe_mb->pdev, + "[%x] Found protocol %d vid: %x prot: %x\n", + doe_mb->cap_offset, xa_idx, vid, prot); + + rc = xa_insert(&doe_mb->prots, xa_idx++, + pci_doe_xa_prot_entry(vid, prot), GFP_KERNEL); + if (rc) + return rc; + } while (index); + + return 0; +} + +static void pci_doe_cancel_tasks(struct pci_doe_mb *doe_mb) +{ + /* Stop all pending work items from starting */ + set_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags); + + /* Cancel an in progress work item, if necessary */ + set_bit(PCI_DOE_FLAG_CANCEL, &doe_mb->flags); + wake_up(&doe_mb->wq); +} + +/** + * pci_doe_create_mb() - Create a DOE mailbox object + * + * @pdev: PCI device to create the DOE mailbox for + * @cap_offset: Offset of the DOE mailbox + * + * Create a single mailbox object to manage the mailbox protocol at the + * cap_offset specified. + * + * RETURNS: created mailbox object on success + * ERR_PTR(-errno) on failure + */ +static struct pci_doe_mb *pci_doe_create_mb(struct pci_dev *pdev, + u16 cap_offset) +{ + struct pci_doe_mb *doe_mb; + int rc; + + doe_mb = kzalloc(sizeof(*doe_mb), GFP_KERNEL); + if (!doe_mb) + return ERR_PTR(-ENOMEM); + + doe_mb->pdev = pdev; + doe_mb->cap_offset = cap_offset; + init_waitqueue_head(&doe_mb->wq); + xa_init(&doe_mb->prots); + + doe_mb->work_queue = alloc_ordered_workqueue("%s %s DOE [%x]", 0, + dev_bus_name(&pdev->dev), + pci_name(pdev), + doe_mb->cap_offset); + if (!doe_mb->work_queue) { + pci_err(pdev, "[%x] failed to allocate work queue\n", + doe_mb->cap_offset); + rc = -ENOMEM; + goto err_free; + } + + /* Reset the mailbox by issuing an abort */ + rc = pci_doe_abort(doe_mb); + if (rc) { + pci_err(pdev, "[%x] failed to reset mailbox with abort command : %d\n", + doe_mb->cap_offset, rc); + goto err_destroy_wq; + } + + /* + * The state machine and the mailbox should be in sync now; + * Use the mailbox to query protocols. + */ + rc = pci_doe_cache_protocols(doe_mb); + if (rc) { + pci_err(pdev, "[%x] failed to cache protocols : %d\n", + doe_mb->cap_offset, rc); + goto err_cancel; + } + + return doe_mb; + +err_cancel: + pci_doe_cancel_tasks(doe_mb); + xa_destroy(&doe_mb->prots); +err_destroy_wq: + destroy_workqueue(doe_mb->work_queue); +err_free: + kfree(doe_mb); + return ERR_PTR(rc); +} + +/** + * pci_doe_destroy_mb() - Destroy a DOE mailbox object + * + * @doe_mb: DOE mailbox + * + * Destroy all internal data structures created for the DOE mailbox. + */ +static void pci_doe_destroy_mb(struct pci_doe_mb *doe_mb) +{ + pci_doe_cancel_tasks(doe_mb); + xa_destroy(&doe_mb->prots); + destroy_workqueue(doe_mb->work_queue); + kfree(doe_mb); +} + +/** + * pci_doe_supports_prot() - Return if the DOE instance supports the given + * protocol + * @doe_mb: DOE mailbox capability to query + * @vid: Protocol Vendor ID + * @type: Protocol type + * + * RETURNS: True if the DOE mailbox supports the protocol specified + */ +static bool pci_doe_supports_prot(struct pci_doe_mb *doe_mb, u16 vid, u8 type) +{ + unsigned long index; + void *entry; + + /* The discovery protocol must always be supported */ + if (vid == PCI_VENDOR_ID_PCI_SIG && type == PCI_DOE_PROTOCOL_DISCOVERY) + return true; + + xa_for_each(&doe_mb->prots, index, entry) + if (entry == pci_doe_xa_prot_entry(vid, type)) + return true; + + return false; +} + +/** + * pci_doe_submit_task() - Submit a task to be processed by the state machine + * + * @doe_mb: DOE mailbox capability to submit to + * @task: task to be queued + * + * Submit a DOE task (request/response) to the DOE mailbox to be processed. + * Returns upon queueing the task object. If the queue is full this function + * will sleep until there is room in the queue. + * + * task->complete will be called when the state machine is done processing this + * task. + * + * @task must be allocated on the stack. + * + * Excess data will be discarded. + * + * RETURNS: 0 when task has been successfully queued, -ERRNO on error + */ +static int pci_doe_submit_task(struct pci_doe_mb *doe_mb, + struct pci_doe_task *task) +{ + if (!pci_doe_supports_prot(doe_mb, task->prot.vid, task->prot.type)) + return -EINVAL; + + if (test_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags)) + return -EIO; + + task->doe_mb = doe_mb; + INIT_WORK_ONSTACK(&task->work, doe_statemachine_work); + queue_work(doe_mb->work_queue, &task->work); + return 0; +} + +/** + * pci_doe() - Perform Data Object Exchange + * + * @doe_mb: DOE Mailbox + * @vendor: Vendor ID + * @type: Data Object Type + * @request: Request payload + * @request_sz: Size of request payload (bytes) + * @response: Response payload + * @response_sz: Size of response payload (bytes) + * + * Submit @request to @doe_mb and store the @response. + * The DOE exchange is performed synchronously and may therefore sleep. + * + * Payloads are treated as opaque byte streams which are transmitted verbatim, + * without byte-swapping. If payloads contain little-endian register values, + * the caller is responsible for conversion with cpu_to_le32() / le32_to_cpu(). + * + * For convenience, arbitrary payload sizes are allowed even though PCIe r6.0 + * sec 6.30.1 specifies the Data Object Header 2 "Length" in dwords. The last + * (partial) dword is copied with byte granularity and padded with zeroes if + * necessary. Callers are thus relieved of using dword-sized bounce buffers. + * + * RETURNS: Length of received response or negative errno. + * Received data in excess of @response_sz is discarded. + * The length may be smaller than @response_sz and the caller + * is responsible for checking that. + */ +int pci_doe(struct pci_doe_mb *doe_mb, u16 vendor, u8 type, + const void *request, size_t request_sz, + void *response, size_t response_sz) +{ + DECLARE_COMPLETION_ONSTACK(c); + struct pci_doe_task task = { + .prot.vid = vendor, + .prot.type = type, + .request_pl = request, + .request_pl_sz = request_sz, + .response_pl = response, + .response_pl_sz = response_sz, + .complete = pci_doe_task_complete, + .private = &c, + }; + int rc; + + rc = pci_doe_submit_task(doe_mb, &task); + if (rc) + return rc; + + wait_for_completion(&c); + + return task.rv; +} +EXPORT_SYMBOL_GPL(pci_doe); + +/** + * pci_find_doe_mailbox() - Find Data Object Exchange mailbox + * + * @pdev: PCI device + * @vendor: Vendor ID + * @type: Data Object Type + * + * Find first DOE mailbox of a PCI device which supports the given protocol. + * + * RETURNS: Pointer to the DOE mailbox or NULL if none was found. + */ +struct pci_doe_mb *pci_find_doe_mailbox(struct pci_dev *pdev, u16 vendor, + u8 type) +{ + struct pci_doe_mb *doe_mb; + unsigned long index; + + xa_for_each(&pdev->doe_mbs, index, doe_mb) + if (pci_doe_supports_prot(doe_mb, vendor, type)) + return doe_mb; + + return NULL; +} +EXPORT_SYMBOL_GPL(pci_find_doe_mailbox); + +void pci_doe_init(struct pci_dev *pdev) +{ + struct pci_doe_mb *doe_mb; + u16 offset = 0; + int rc; + + xa_init(&pdev->doe_mbs); + + while ((offset = pci_find_next_ext_capability(pdev, offset, + PCI_EXT_CAP_ID_DOE))) { + doe_mb = pci_doe_create_mb(pdev, offset); + if (IS_ERR(doe_mb)) { + pci_err(pdev, "[%x] failed to create mailbox: %ld\n", + offset, PTR_ERR(doe_mb)); + continue; + } + + rc = xa_insert(&pdev->doe_mbs, offset, doe_mb, GFP_KERNEL); + if (rc) { + pci_err(pdev, "[%x] failed to insert mailbox: %d\n", + offset, rc); + pci_doe_destroy_mb(doe_mb); + } + } +} + +void pci_doe_destroy(struct pci_dev *pdev) +{ + struct pci_doe_mb *doe_mb; + unsigned long index; + + xa_for_each(&pdev->doe_mbs, index, doe_mb) + pci_doe_destroy_mb(doe_mb); + + xa_destroy(&pdev->doe_mbs); +} + +void pci_doe_disconnected(struct pci_dev *pdev) +{ + struct pci_doe_mb *doe_mb; + unsigned long index; + + xa_for_each(&pdev->doe_mbs, index, doe_mb) + pci_doe_cancel_tasks(doe_mb); +} |