@@ -190,6 +190,14 @@ config PCI_HYPERV
The PCI device frontend driver allows the kernel to import arbitrary
PCI devices from a PCI backend to support PCI driver domains.
+config PCI_DOE
+ bool
+ help
+ This enables library support for the PCI Data Object Exchange
+ capability. DOE provides a simple mailbox in PCI config space that is
+ used by a number of different protocols.
+ DOE is defined in the Data Object Exchange ECN to the PCIe r5.0 spec.
+
choice
prompt "PCI Express hierarchy optimization setting"
default PCIE_BUS_DEFAULT
@@ -28,6 +28,7 @@ obj-$(CONFIG_PCI_STUB) += pci-stub.o
obj-$(CONFIG_PCI_PF_STUB) += pci-pf-stub.o
obj-$(CONFIG_PCI_ECAM) += ecam.o
obj-$(CONFIG_PCI_P2PDMA) += p2pdma.o
+obj-$(CONFIG_PCI_DOE) += doe.o
obj-$(CONFIG_XEN_PCIDEV_FRONTEND) += xen-pcifront.o
# Endpoint library must be initialized before its users
new file mode 100644
@@ -0,0 +1,626 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Data Object Exchange ECN
+ * https://members.pcisig.com/wg/PCI-SIG/document/14143
+ *
+ * Copyright (C) 2021 Huawei
+ * Jonathan Cameron <Jonathan.Cameron@huawei.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/jiffies.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/pci.h>
+#include <linux/pci-doe.h>
+#include <linux/workqueue.h>
+
+#define PCI_DOE_PROTOCOL_DISCOVERY 0
+
+#define PCI_DOE_BUSY_MAX_RETRIES 16
+#define PCI_DOE_POLL_INTERVAL (HZ / 128)
+
+/* Timeout of 1 second from 6.xx.1 (Operation), ECN - Data Object Exchange */
+#define PCI_DOE_TIMEOUT HZ
+
+static irqreturn_t pci_doe_irq(int irq, void *data)
+{
+ struct pci_doe *doe = data;
+ struct pci_dev *pdev = doe->pdev;
+ u32 val;
+
+ pci_read_config_dword(pdev, doe->cap + PCI_DOE_STATUS, &val);
+ if (FIELD_GET(PCI_DOE_STATUS_INT_STATUS, val)) {
+ pci_write_config_dword(pdev, doe->cap + PCI_DOE_STATUS, val);
+ mod_delayed_work(system_wq, &doe->statemachine, 0);
+ return IRQ_HANDLED;
+ }
+ /* Leave the error case to be handled outside IRQ */
+ if (FIELD_GET(PCI_DOE_STATUS_ERROR, val)) {
+ mod_delayed_work(system_wq, &doe->statemachine, 0);
+ return IRQ_HANDLED;
+ }
+
+ /*
+ * Busy being cleared can result in an interrupt, but as
+ * the original Busy may not have been detected, there is no
+ * way to separate such an interrupt from a spurious interrupt.
+ */
+ return IRQ_HANDLED;
+}
+
+/*
+ * Only call when safe to directly access the DOE, either because no tasks yet
+ * queued, or called from doe_statemachine_work() which has exclusive access to
+ * the DOE config space.
+ */
+static void pci_doe_abort_start(struct pci_doe *doe)
+{
+ struct pci_dev *pdev = doe->pdev;
+ u32 val;
+
+ val = PCI_DOE_CTRL_ABORT;
+ if (doe->irq)
+ val |= PCI_DOE_CTRL_INT_EN;
+ pci_write_config_dword(pdev, doe->cap + PCI_DOE_CTRL, val);
+
+ doe->timeout_jiffies = jiffies + HZ;
+ schedule_delayed_work(&doe->statemachine, HZ);
+}
+
+static int pci_doe_send_req(struct pci_doe *doe, struct pci_doe_exchange *ex)
+{
+ struct pci_dev *pdev = doe->pdev;
+ 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, doe->cap + PCI_DOE_STATUS, &val);
+ if (FIELD_GET(PCI_DOE_STATUS_BUSY, val))
+ return -EBUSY;
+
+ if (FIELD_GET(PCI_DOE_STATUS_ERROR, val))
+ return -EIO;
+
+ /* Write DOE Header */
+ val = FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_1_VID, ex->vid) |
+ FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_1_TYPE, ex->protocol);
+ pci_write_config_dword(pdev, doe->cap + PCI_DOE_WRITE, val);
+ /* Length is 2 DW of header + length of payload in DW */
+ pci_write_config_dword(pdev, doe->cap + PCI_DOE_WRITE,
+ FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_2_LENGTH,
+ 2 + ex->request_pl_sz / sizeof(u32)));
+ for (i = 0; i < ex->request_pl_sz / sizeof(u32); i++)
+ pci_write_config_dword(pdev, doe->cap + PCI_DOE_WRITE,
+ ex->request_pl[i]);
+
+ val = PCI_DOE_CTRL_GO;
+ if (doe->irq)
+ val |= PCI_DOE_CTRL_INT_EN;
+
+ pci_write_config_dword(pdev, doe->cap + PCI_DOE_CTRL, val);
+ /* Request is sent - now wait for poll or IRQ */
+ return 0;
+}
+
+static int pci_doe_recv_resp(struct pci_doe *doe, struct pci_doe_exchange *ex)
+{
+ struct pci_dev *pdev = doe->pdev;
+ size_t length;
+ u32 val;
+ int i;
+
+ /* Read the first dword to get the protocol */
+ pci_read_config_dword(pdev, doe->cap + PCI_DOE_READ, &val);
+ if ((FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_VID, val) != ex->vid) ||
+ (FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_TYPE, val) != ex->protocol)) {
+ pci_err(pdev,
+ "Expected [VID, Protocol] = [%x, %x], got [%x, %x]\n",
+ ex->vid, ex->protocol,
+ 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, doe->cap + PCI_DOE_READ, 0);
+ /* Read the second dword to get the length */
+ pci_read_config_dword(pdev, doe->cap + PCI_DOE_READ, &val);
+ pci_write_config_dword(pdev, doe->cap + PCI_DOE_READ, 0);
+
+ length = FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_2_LENGTH, val);
+ if (length > SZ_1M || length < 2)
+ return -EIO;
+
+ /* First 2 dwords have already been read */
+ length -= 2;
+ /* Read the rest of the response payload */
+ for (i = 0; i < min(length, ex->response_pl_sz / sizeof(u32)); i++) {
+ pci_read_config_dword(pdev, doe->cap + PCI_DOE_READ,
+ &ex->response_pl[i]);
+ pci_write_config_dword(pdev, doe->cap + PCI_DOE_READ, 0);
+ }
+
+ /* Flush excess length */
+ for (; i < length; i++) {
+ pci_read_config_dword(pdev, doe->cap + PCI_DOE_READ, &val);
+ pci_write_config_dword(pdev, doe->cap + PCI_DOE_READ, 0);
+ }
+ /* Final error check to pick up on any since Data Object Ready */
+ pci_read_config_dword(pdev, doe->cap + PCI_DOE_STATUS, &val);
+ if (FIELD_GET(PCI_DOE_STATUS_ERROR, val))
+ return -EIO;
+
+ return min(length, ex->response_pl_sz / sizeof(u32)) * sizeof(u32);
+}
+
+static void pci_doe_task_complete(void *private)
+{
+ complete(private);
+}
+
+/**
+ * struct pci_doe_task - description of a query / response task
+ * @h: Head to add it to the list of outstanding tasks
+ * @ex: The details of the task to be done
+ * @rv: Return value. Length of received response or error
+ * @cb: Callback for completion of task
+ * @private: Private data passed to callback on completion
+ */
+struct pci_doe_task {
+ struct list_head h;
+ struct pci_doe_exchange *ex;
+ int rv;
+ void (*cb)(void *private);
+ void *private;
+};
+
+/**
+ * pci_doe_exchange_sync() - Send a request, then wait for and receive response
+ * @doe: DOE mailbox state structure
+ * @ex: Description of the buffers and Vendor ID + type used in this
+ * request/response pair
+ *
+ * Excess data will be discarded.
+ *
+ * RETURNS: payload in bytes on success, < 0 on error
+ */
+int pci_doe_exchange_sync(struct pci_doe *doe, struct pci_doe_exchange *ex)
+{
+ struct pci_doe_task task;
+ DECLARE_COMPLETION_ONSTACK(c);
+ int only_task;
+
+ /* DOE requests must be a whole number of DW */
+ if (ex->request_pl_sz % sizeof(u32))
+ return -EINVAL;
+
+ task.ex = ex;
+ task.cb = pci_doe_task_complete;
+ task.private = &c;
+
+ mutex_lock(&doe->tasks_lock);
+ if (doe->dead) {
+ mutex_unlock(&doe->tasks_lock);
+ return -EIO;
+ }
+ only_task = list_empty(&doe->tasks);
+ list_add_tail(&task.h, &doe->tasks);
+ if (only_task)
+ schedule_delayed_work(&doe->statemachine, 0);
+ mutex_unlock(&doe->tasks_lock);
+ wait_for_completion(&c);
+
+ return task.rv;
+}
+EXPORT_SYMBOL_GPL(pci_doe_exchange_sync);
+
+static void doe_statemachine_work(struct work_struct *work)
+{
+ struct delayed_work *w = to_delayed_work(work);
+ struct pci_doe *doe = container_of(w, struct pci_doe, statemachine);
+ struct pci_dev *pdev = doe->pdev;
+ struct pci_doe_task *task;
+ bool abort;
+ u32 val;
+ int rc;
+
+ mutex_lock(&doe->tasks_lock);
+ task = list_first_entry_or_null(&doe->tasks, struct pci_doe_task, h);
+ abort = doe->abort;
+ doe->abort = false;
+ mutex_unlock(&doe->tasks_lock);
+
+ if (abort) {
+ /*
+ * Currently only used during init - care needed if we want to
+ * generally expose pci_doe_abort() as it would impact queries
+ * in flight.
+ */
+ WARN_ON(task);
+ doe->state = DOE_WAIT_ABORT;
+ pci_doe_abort_start(doe);
+ return;
+ }
+
+ switch (doe->state) {
+ case DOE_IDLE:
+ if (task == NULL)
+ return;
+
+ /* Nothing currently in flight so queue a task */
+ rc = pci_doe_send_req(doe, task->ex);
+ /*
+ * The specification does not provide any guidance on how long
+ * some other entity could keep the DOE busy, so try for 1
+ * second then fail. Busy handling is best effort only, because
+ * there is no way of avoiding racing against another user of
+ * the DOE.
+ */
+ if (rc == -EBUSY) {
+ doe->busy_retries++;
+ if (doe->busy_retries == PCI_DOE_BUSY_MAX_RETRIES) {
+ /* Long enough, fail this request */
+ pci_WARN(pdev, true, "DOE busy for too long\n");
+ doe->busy_retries = 0;
+ goto err_busy;
+ }
+ schedule_delayed_work(w, HZ / PCI_DOE_BUSY_MAX_RETRIES);
+ return;
+ }
+ if (rc)
+ goto err_abort;
+ doe->busy_retries = 0;
+
+ doe->state = DOE_WAIT_RESP;
+ doe->timeout_jiffies = jiffies + HZ;
+ /* Now poll or wait for IRQ with timeout */
+ if (doe->irq > 0)
+ schedule_delayed_work(w, PCI_DOE_TIMEOUT);
+ else
+ schedule_delayed_work(w, PCI_DOE_POLL_INTERVAL);
+ return;
+
+ case DOE_WAIT_RESP:
+ /* Not possible to get here with NULL task */
+ pci_read_config_dword(pdev, doe->cap + PCI_DOE_STATUS, &val);
+ if (FIELD_GET(PCI_DOE_STATUS_ERROR, val)) {
+ rc = -EIO;
+ goto err_abort;
+ }
+
+ if (!FIELD_GET(PCI_DOE_STATUS_DATA_OBJECT_READY, val)) {
+ /* If not yet at timeout reschedule otherwise abort */
+ if (time_after(jiffies, doe->timeout_jiffies)) {
+ rc = -ETIMEDOUT;
+ goto err_abort;
+ }
+ schedule_delayed_work(w, PCI_DOE_POLL_INTERVAL);
+ return;
+ }
+
+ rc = pci_doe_recv_resp(doe, task->ex);
+ if (rc < 0)
+ goto err_abort;
+
+ doe->state = DOE_IDLE;
+
+ mutex_lock(&doe->tasks_lock);
+ list_del(&task->h);
+ if (!list_empty(&doe->tasks))
+ schedule_delayed_work(w, 0);
+ mutex_unlock(&doe->tasks_lock);
+
+ /* Set the return value to the length of received payload */
+ task->rv = rc;
+ task->cb(task->private);
+ return;
+
+ case DOE_WAIT_ABORT:
+ case DOE_WAIT_ABORT_ON_ERR:
+ pci_read_config_dword(pdev, doe->cap + PCI_DOE_STATUS, &val);
+
+ if (!FIELD_GET(PCI_DOE_STATUS_ERROR, val) &&
+ !FIELD_GET(PCI_DOE_STATUS_BUSY, val)) {
+ /* Back to normal state - carry on */
+ mutex_lock(&doe->tasks_lock);
+ if (!list_empty(&doe->tasks))
+ schedule_delayed_work(w, 0);
+ mutex_unlock(&doe->tasks_lock);
+
+ /*
+ * For deliberately triggered abort, someone is
+ * waiting.
+ */
+ if (doe->state == DOE_WAIT_ABORT)
+ complete(&doe->abort_c);
+ doe->state = DOE_IDLE;
+
+ return;
+ }
+ if (time_after(jiffies, doe->timeout_jiffies)) {
+ struct pci_doe_task *t, *n;
+
+ /* We are dead - abort all queued tasks */
+ pci_err(pdev, "DOE ABORT timed out\n");
+ mutex_lock(&doe->tasks_lock);
+ doe->dead = true;
+ list_for_each_entry_safe(t, n, &doe->tasks, h) {
+ t->rv = -EIO;
+ t->cb(t->private);
+ list_del(&t->h);
+ }
+
+ mutex_unlock(&doe->tasks_lock);
+ if (doe->state == DOE_WAIT_ABORT)
+ complete(&doe->abort_c);
+ }
+ return;
+ }
+
+err_abort:
+ doe->state = DOE_WAIT_ABORT_ON_ERR;
+ pci_doe_abort_start(doe);
+err_busy:
+ mutex_lock(&doe->tasks_lock);
+ list_del(&task->h);
+ mutex_unlock(&doe->tasks_lock);
+
+ task->rv = rc;
+ task->cb(task->private);
+ /*
+ * If we got here via err_busy, and the queue isn't empty then we need
+ * to go again.
+ */
+ if (doe->state == DOE_IDLE) {
+ mutex_lock(&doe->tasks_lock);
+ if (!list_empty(&doe->tasks))
+ schedule_delayed_work(w, 0);
+ mutex_unlock(&doe->tasks_lock);
+ }
+}
+
+static int pci_doe_discovery(struct pci_doe *doe, u8 *index, u16 *vid,
+ u8 *protocol)
+{
+ u32 request_pl = FIELD_PREP(PCI_DOE_DATA_OBJECT_DISC_REQ_3_INDEX, *index);
+ u32 response_pl;
+ struct pci_doe_exchange ex = {
+ .vid = PCI_VENDOR_ID_PCI_SIG,
+ .protocol = PCI_DOE_PROTOCOL_DISCOVERY,
+ .request_pl = &request_pl,
+ .request_pl_sz = sizeof(request_pl),
+ .response_pl = &response_pl,
+ .response_pl_sz = sizeof(response_pl),
+ };
+ int ret;
+
+ ret = pci_doe_exchange_sync(doe, &ex);
+ if (ret < 0)
+ return ret;
+
+ if (ret != sizeof(response_pl))
+ return -EIO;
+
+ *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 int pci_doe_cache_protocols(struct pci_doe *doe)
+{
+ u8 index = 0;
+ int rc;
+
+ /* Discovery protocol must always be supported and must report itself */
+ doe->num_prots = 1;
+ doe->prots = kzalloc(sizeof(*doe->prots) * doe->num_prots, GFP_KERNEL);
+ if (doe->prots == NULL)
+ return -ENOMEM;
+
+ do {
+ struct pci_doe_prot *prot, *prot_new;
+
+ prot = &doe->prots[doe->num_prots - 1];
+ rc = pci_doe_discovery(doe, &index, &prot->vid, &prot->type);
+ if (rc)
+ goto err_free_prots;
+
+ if (index) {
+ prot_new = krealloc(doe->prots,
+ sizeof(*doe->prots) * doe->num_prots,
+ GFP_KERNEL);
+ if (prot_new == NULL) {
+ rc = -ENOMEM;
+ goto err_free_prots;
+ }
+ doe->prots = prot_new;
+ doe->num_prots++;
+ }
+ } while (index);
+
+ return 0;
+
+err_free_prots:
+ kfree(doe->prots);
+ return rc;
+}
+
+static void pci_doe_init(struct pci_doe *doe, struct pci_dev *pdev,
+ int doe_offset)
+{
+ mutex_init(&doe->tasks_lock);
+ init_completion(&doe->abort_c);
+ doe->cap = doe_offset;
+ doe->pdev = pdev;
+ INIT_LIST_HEAD(&doe->tasks);
+ INIT_DELAYED_WORK(&doe->statemachine, doe_statemachine_work);
+}
+
+static int pci_doe_abort(struct pci_doe *doe)
+{
+ reinit_completion(&doe->abort_c);
+ mutex_lock(&doe->tasks_lock);
+ doe->abort = true;
+ mutex_unlock(&doe->tasks_lock);
+ schedule_delayed_work(&doe->statemachine, 0);
+ wait_for_completion(&doe->abort_c);
+
+ if (doe->dead)
+ return -EIO;
+
+ return 0;
+}
+
+static int pci_doe_register(struct pci_doe *doe)
+{
+ struct pci_dev *pdev = doe->pdev;
+ bool poll = !pci_dev_msi_enabled(pdev);
+ int rc, irq;
+ u32 val;
+
+ pci_read_config_dword(pdev, doe->cap + PCI_DOE_CAP, &val);
+
+ if (!poll && FIELD_GET(PCI_DOE_CAP_INT, val)) {
+ irq = pci_irq_vector(pdev, FIELD_GET(PCI_DOE_CAP_IRQ, val));
+ if (irq < 0)
+ return irq;
+
+ doe->irq_name = kasprintf(GFP_KERNEL, "DOE[%s]_%x",
+ dev_name(&pdev->dev), doe->cap);
+ if (!doe->irq_name)
+ return -ENOMEM;
+
+ rc = request_irq(irq, pci_doe_irq, 0, doe->irq_name, doe);
+ if (rc)
+ goto err_free_name;
+
+ doe->irq = irq;
+ pci_write_config_dword(pdev, doe->cap + PCI_DOE_CTRL,
+ PCI_DOE_CTRL_INT_EN);
+ }
+
+ /* Reset the mailbox by issuing an abort */
+ rc = pci_doe_abort(doe);
+ if (rc)
+ goto err_free_irqs;
+
+ return 0;
+
+err_free_irqs:
+ if (doe->irq > 0)
+ free_irq(doe->irq, doe);
+err_free_name:
+ kfree(doe->irq_name);
+
+ return rc;
+}
+
+static void pci_doe_unregister(struct pci_doe *doe)
+{
+ if (doe->irq > 0)
+ free_irq(doe->irq, doe);
+ kfree(doe->irq_name);
+}
+
+void pci_doe_unregister_all(struct pci_dev *pdev)
+{
+ struct pci_doe *doe, *next;
+
+ list_for_each_entry_safe(doe, next, &pdev->doe_list, h) {
+ /* First halt the state machine */
+ cancel_delayed_work_sync(&doe->statemachine);
+ kfree(doe->prots);
+ pci_doe_unregister(doe);
+ kfree(doe);
+ }
+}
+EXPORT_SYMBOL_GPL(pci_doe_unregister_all);
+
+/**
+ * pci_doe_register_all() - Find and register all DOE mailboxes
+ * @pdev: PCI device whose DOE mailboxes we are finding
+ *
+ * Will locate any DOE mailboxes present on the device and cache the protocols
+ * so that pci_doe_find() can be used to retrieve a suitable DOE instance.
+ *
+ * DOE mailboxes are available until pci_doe_unregister_all() is called.
+ *
+ * RETURNS: 0 on success, < 0 on error
+ */
+int pci_doe_register_all(struct pci_dev *pdev)
+{
+ struct pci_doe *doe;
+ int pos = 0;
+ int rc;
+
+ INIT_LIST_HEAD(&pdev->doe_list);
+
+ /* Walk the DOE extended capabilities and add to per pci_dev list */
+ while (true) {
+ pos = pci_find_next_ext_capability(pdev, pos,
+ PCI_EXT_CAP_ID_DOE);
+ if (!pos)
+ return 0;
+
+ doe = kzalloc(sizeof(*doe), GFP_KERNEL);
+ if (!doe) {
+ rc = -ENOMEM;
+ goto err_free_does;
+ }
+
+ pci_doe_init(doe, pdev, pos);
+ rc = pci_doe_register(doe);
+ if (rc) {
+ kfree(doe);
+ goto err_free_does;
+ }
+
+ rc = pci_doe_cache_protocols(doe);
+ if (rc) {
+ pci_doe_unregister(doe);
+ kfree(doe);
+ goto err_free_does;
+ }
+
+ list_add(&doe->h, &pdev->doe_list);
+ }
+
+err_free_does:
+ pci_doe_unregister_all(pdev);
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(pci_doe_register_all);
+
+/**
+ * pci_doe_find() - Find the first DOE instance that supports a given protocol
+ * @pdev: Device on which to find the DOE instance
+ * @vid: Vendor ID
+ * @type: Specific protocol for this vendor
+ *
+ * RETURNS: Pointer to DOE instance on success, NULL on no suitable instance
+ * available
+ */
+struct pci_doe *pci_doe_find(struct pci_dev *pdev, u16 vid, u8 type)
+{
+ struct pci_doe *doe;
+ int i;
+
+ list_for_each_entry(doe, &pdev->doe_list, h) {
+ for (i = 0; i < doe->num_prots; i++)
+ if ((doe->prots[i].vid == vid) &&
+ (doe->prots[i].type == type))
+ return doe;
+ }
+
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(pci_doe_find);
new file mode 100644
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Data Object Exchange was added as an ECN to the PCIe r5.0 spec.
+ *
+ * Copyright (C) 2021 Huawei
+ * Jonathan Cameron <Jonathan.Cameron@huawei.com>
+ */
+
+#include <linux/completion.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+
+#ifndef LINUX_PCI_DOE_H
+#define LINUX_PCI_DOE_H
+
+struct pci_doe_prot {
+ u16 vid;
+ u8 type;
+};
+
+struct workqueue_struct;
+
+enum pci_doe_state {
+ DOE_IDLE,
+ DOE_WAIT_RESP,
+ DOE_WAIT_ABORT,
+ DOE_WAIT_ABORT_ON_ERR,
+};
+
+struct pci_doe_exchange {
+ u16 vid;
+ u8 protocol;
+ u32 *request_pl;
+ size_t request_pl_sz;
+ u32 *response_pl;
+ size_t response_pl_sz;
+};
+
+/**
+ * struct pci_doe - State to support use of DOE mailbox
+ * @cap: Config space offset to base of DOE capability
+ * @pdev: PCI device that hosts this DOE
+ * @abort_c: Completion used for initial abort handling
+ * @irq: Interrupt used for signaling DOE ready or abort
+ * @irq_name: Name used to identify the irq for a particular DOE
+ * @prots: Cache of identifiers for protocols supported
+ * @num_prots: Size of prots cache
+ * @h: Used for DOE instance lifetime management
+ * @wq: Workqueue used to handle state machine and polling / timeouts
+ * @tasks: List of task in flight + pending
+ * @tasks_lock: Protect the tasks list and abort state
+ * @statemachine: Work item for the DOE state machine
+ * @state: Current state of this DOE
+ * @timeout_jiffies: 1 second after GO set
+ * @busy_retries: Count of retry attempts
+ * @abort: Request a manual abort (e.g. on init)
+ * @dead: Used to mark a DOE for which an ABORT has timed out. Further messages
+ * will immediately be aborted with error
+ */
+struct pci_doe {
+ int cap;
+ struct pci_dev *pdev;
+ struct completion abort_c;
+ int irq;
+ char *irq_name;
+ struct pci_doe_prot *prots;
+ int num_prots;
+ struct list_head h;
+
+ struct workqueue_struct *wq;
+ struct list_head tasks;
+ struct mutex tasks_lock;
+ struct delayed_work statemachine;
+ enum pci_doe_state state;
+ unsigned long timeout_jiffies;
+ unsigned int busy_retries;
+ unsigned int abort:1;
+ unsigned int dead:1;
+};
+
+int pci_doe_register_all(struct pci_dev *pdev);
+void pci_doe_unregister_all(struct pci_dev *pdev);
+struct pci_doe *pci_doe_find(struct pci_dev *pdev, u16 vid, u8 type);
+
+int pci_doe_exchange_sync(struct pci_doe *doe, struct pci_doe_exchange *ex);
+
+#endif
@@ -332,6 +332,9 @@ struct pci_dev {
#ifdef CONFIG_PCIEPORTBUS
struct rcec_ea *rcec_ea; /* RCEC cached endpoint association */
struct pci_dev *rcec; /* Associated RCEC device */
+#endif
+#ifdef CONFIG_PCI_DOE
+ struct list_head doe_list; /* Data Object Exchange mailboxes */
#endif
u8 pcie_cap; /* PCIe capability offset */
u8 msi_cap; /* MSI capability offset */
@@ -730,7 +730,8 @@
#define PCI_EXT_CAP_ID_DVSEC 0x23 /* Designated Vendor-Specific */
#define PCI_EXT_CAP_ID_DLF 0x25 /* Data Link Feature */
#define PCI_EXT_CAP_ID_PL_16GT 0x26 /* Physical Layer 16.0 GT/s */
-#define PCI_EXT_CAP_ID_MAX PCI_EXT_CAP_ID_PL_16GT
+#define PCI_EXT_CAP_ID_DOE 0x2E /* Data Object Exchange */
+#define PCI_EXT_CAP_ID_MAX PCI_EXT_CAP_ID_DOE
#define PCI_EXT_CAP_DSN_SIZEOF 12
#define PCI_EXT_CAP_MCAST_ENDPOINT_SIZEOF 40
@@ -1092,4 +1093,30 @@
#define PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_MASK 0x000000F0
#define PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_SHIFT 4
+/* Data Object Exchange */
+#define PCI_DOE_CAP 0x04 /* DOE Capabilities Register */
+#define PCI_DOE_CAP_INT 0x00000001 /* Interrupt Support */
+#define PCI_DOE_CAP_IRQ 0x00000ffe /* Interrupt Message Number */
+#define PCI_DOE_CTRL 0x08 /* DOE Control Register */
+#define PCI_DOE_CTRL_ABORT 0x00000001 /* DOE Abort */
+#define PCI_DOE_CTRL_INT_EN 0x00000002 /* DOE Interrupt Enable */
+#define PCI_DOE_CTRL_GO 0x80000000 /* DOE Go */
+#define PCI_DOE_STATUS 0x0c /* DOE Status Register */
+#define PCI_DOE_STATUS_BUSY 0x00000001 /* DOE Busy */
+#define PCI_DOE_STATUS_INT_STATUS 0x00000002 /* DOE Interrupt Status */
+#define PCI_DOE_STATUS_ERROR 0x00000004 /* DOE Error */
+#define PCI_DOE_STATUS_DATA_OBJECT_READY 0x80000000 /* Data Object Ready */
+#define PCI_DOE_WRITE 0x10 /* DOE Write Data Mailbox Register */
+#define PCI_DOE_READ 0x14 /* DOE Read Data Mailbox Register */
+
+/* DOE Data Object - note not actually registers */
+#define PCI_DOE_DATA_OBJECT_HEADER_1_VID 0x0000ffff
+#define PCI_DOE_DATA_OBJECT_HEADER_1_TYPE 0x00ff0000
+#define PCI_DOE_DATA_OBJECT_HEADER_2_LENGTH 0x0003ffff
+
+#define PCI_DOE_DATA_OBJECT_DISC_REQ_3_INDEX 0x000000ff
+#define PCI_DOE_DATA_OBJECT_DISC_RSP_3_VID 0x0000ffff
+#define PCI_DOE_DATA_OBJECT_DISC_RSP_3_PROTOCOL 0x00ff0000
+#define PCI_DOE_DATA_OBJECT_DISC_RSP_3_NEXT_INDEX 0xff000000
+
#endif /* LINUX_PCI_REGS_H */
Introduced in a PCI ECN [1], DOE provides a config space based mailbox with standard protocol discovery. Each mailbox is accessed through a DOE Extended Capability. A device may have 1 or more DOE mailboxes, each of which is allowed to support any number of protocols (some DOE protocol specifications apply additional restrictions). A given protocol may be supported on more than one DOE mailbox on a given function. If a driver wishes to access any number of DOE instances / protocols it makes a single call to pci_doe_register_all() which will find available DOEs, create the required infrastructure and cache the protocols they support. pci_doe_find() can then retrieve a pointer to an appropriate DOE instance. A synchronous interface is provided in pci_doe_exchange_sync() to perform a single query / response exchange. Testing conducted against QEMU using: https://lore.kernel.org/qemu-devel/1619454964-10190-1-git-send-email-cbrowy@avery-design.com/ [1] https://members.pcisig.com/wg/PCI-SIG/document/14143 Data Object Exchange (DOE) - Approved 12 March 2020 Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> --- drivers/pci/Kconfig | 8 + drivers/pci/Makefile | 1 + drivers/pci/doe.c | 626 ++++++++++++++++++++++++++++++++++ include/linux/pci-doe.h | 87 +++++ include/linux/pci.h | 3 + include/uapi/linux/pci_regs.h | 29 +- 6 files changed, 753 insertions(+), 1 deletion(-)