@@ -153,9 +153,9 @@ Endpoint function can be specified in one trace. Specifying both Root Port
and function at the same time is not supported. Driver maintains a list of
available filters and will check the invalid inputs.
-Currently the available filters are detected in driver's probe. If the supported
-devices are removed/added after probe, you may need to reload the driver to update
-the filters.
+The available filters will be dynamically updates, which means you will always
+get correct filter information when hotplug events happen, or when you manually
+remove/rescan the devices.
2. Type
-------
@@ -354,6 +354,117 @@ static int hisi_ptt_register_irq(struct hisi_ptt *hisi_ptt)
return 0;
}
+static void hisi_ptt_update_filters(struct work_struct *work)
+{
+ struct delayed_work *delayed_work = to_delayed_work(work);
+ struct hisi_ptt_filter_update_info info;
+ struct hisi_ptt_filter_desc *filter;
+ struct list_head *target_list;
+ struct hisi_ptt *hisi_ptt;
+
+ hisi_ptt = container_of(delayed_work, struct hisi_ptt, work);
+
+ if (!mutex_trylock(&hisi_ptt->filter_lock)) {
+ schedule_delayed_work(&hisi_ptt->work, HISI_PTT_WORK_DELAY_MS);
+ return;
+ }
+
+ while (kfifo_get(&hisi_ptt->filter_update_kfifo, &info)) {
+ bool is_port = pci_pcie_type(info.pdev) == PCI_EXP_TYPE_ROOT_PORT;
+ u16 devid = PCI_DEVID(info.pdev->bus->number, info.pdev->devfn);
+ u16 val = hisi_ptt_get_filter_val(devid, is_port);
+
+ target_list = is_port ? &hisi_ptt->port_filters : &hisi_ptt->req_filters;
+
+ if (info.is_add) {
+ filter = kzalloc(sizeof(*filter), GFP_KERNEL);
+ if (!filter) {
+ pci_err(hisi_ptt->pdev, "failed to add filter %s\n",
+ pci_name(info.pdev));
+ continue;
+ }
+
+ filter->devid = devid;
+ filter->is_port = is_port;
+ list_add_tail(&filter->list, target_list);
+
+ if (is_port)
+ hisi_ptt->port_mask |= val;
+ } else {
+ list_for_each_entry(filter, target_list, list)
+ if (filter->devid == devid) {
+ list_del(&filter->list);
+ kfree(filter);
+ break;
+ }
+
+ if (is_port)
+ hisi_ptt->port_mask &= ~val;
+ }
+ }
+
+ mutex_unlock(&hisi_ptt->filter_lock);
+}
+
+static void hisi_ptt_update_fifo_in(struct hisi_ptt *hisi_ptt,
+ struct hisi_ptt_filter_update_info *info)
+{
+ struct pci_dev *root_port = pcie_find_root_port(info->pdev);
+ u32 port_devid;
+
+ if (!root_port)
+ return;
+
+ port_devid = PCI_DEVID(root_port->bus->number, root_port->devfn);
+ if (port_devid < hisi_ptt->lower_bdf ||
+ port_devid > hisi_ptt->upper_bdf)
+ return;
+
+ /*
+ * The FIFO size is 16 which is sufficient for almost all the cases,
+ * since each PCIe core will have most 8 Root Ports (typically only
+ * 1~4 Root Ports). On failure log the failed filter and let user
+ * handle it.
+ */
+ if (kfifo_in_spinlocked(&hisi_ptt->filter_update_kfifo, info, 1,
+ &hisi_ptt->filter_update_lock))
+ schedule_delayed_work(&hisi_ptt->work, 0);
+ else
+ pci_warn(hisi_ptt->pdev,
+ "filter update fifo overflow for target %s\n",
+ pci_name(info->pdev));
+}
+
+/*
+ * A PCI bus notifier is used here for dynamically updating the filter
+ * list.
+ */
+static int hisi_ptt_notifier_call(struct notifier_block *nb, unsigned long action,
+ void *data)
+{
+ struct hisi_ptt *hisi_ptt = container_of(nb, struct hisi_ptt, hisi_ptt_nb);
+ struct hisi_ptt_filter_update_info info;
+ struct device *dev = data;
+ struct pci_dev *pdev = to_pci_dev(dev);
+
+ info.pdev = pdev;
+
+ switch (action) {
+ case BUS_NOTIFY_ADD_DEVICE:
+ info.is_add = true;
+ break;
+ case BUS_NOTIFY_DEL_DEVICE:
+ info.is_add = false;
+ break;
+ default:
+ return 0;
+ }
+
+ hisi_ptt_update_fifo_in(hisi_ptt, &info);
+
+ return 0;
+}
+
static int hisi_ptt_init_filters(struct pci_dev *pdev, void *data)
{
struct pci_dev *root_port = pcie_find_root_port(pdev);
@@ -451,8 +562,13 @@ static int hisi_ptt_init_ctrls(struct hisi_ptt *hisi_ptt)
int ret;
u32 reg;
+ INIT_DELAYED_WORK(&hisi_ptt->work, hisi_ptt_update_filters);
+ INIT_KFIFO(hisi_ptt->filter_update_kfifo);
+ spin_lock_init(&hisi_ptt->filter_update_lock);
+
INIT_LIST_HEAD(&hisi_ptt->port_filters);
INIT_LIST_HEAD(&hisi_ptt->req_filters);
+ mutex_init(&hisi_ptt->filter_lock);
ret = hisi_ptt_config_trace_buf(hisi_ptt);
if (ret)
@@ -627,14 +743,19 @@ static int hisi_ptt_trace_valid_filter(struct hisi_ptt *hisi_ptt, u64 config)
* For Requester ID filters, walk the available filter list to see
* whether we have one matched.
*/
+ mutex_lock(&hisi_ptt->filter_lock);
if (!hisi_ptt->trace_ctrl.is_port) {
list_for_each_entry(filter, &hisi_ptt->req_filters, list) {
- if (val == hisi_ptt_get_filter_val(filter->devid, filter->is_port))
+ if (val == hisi_ptt_get_filter_val(filter->devid, filter->is_port)) {
+ mutex_unlock(&hisi_ptt->filter_lock);
return 0;
+ }
}
} else if (bitmap_subset(&val, &port_mask, BITS_PER_LONG)) {
+ mutex_unlock(&hisi_ptt->filter_lock);
return 0;
}
+ mutex_unlock(&hisi_ptt->filter_lock);
return -EINVAL;
}
@@ -910,6 +1031,31 @@ static int hisi_ptt_register_pmu(struct hisi_ptt *hisi_ptt)
&hisi_ptt->hisi_ptt_pmu);
}
+static void hisi_ptt_unregister_filter_update_notifier(void *data)
+{
+ struct hisi_ptt *hisi_ptt = data;
+
+ bus_unregister_notifier(&pci_bus_type, &hisi_ptt->hisi_ptt_nb);
+
+ /* Cancel any work that has been queued */
+ cancel_delayed_work_sync(&hisi_ptt->work);
+}
+
+/* Register the bus notifier for dynamically updating the filter list */
+static int hisi_ptt_register_filter_update_notifier(struct hisi_ptt *hisi_ptt)
+{
+ int ret;
+
+ hisi_ptt->hisi_ptt_nb.notifier_call = hisi_ptt_notifier_call;
+ ret = bus_register_notifier(&pci_bus_type, &hisi_ptt->hisi_ptt_nb);
+ if (ret)
+ return ret;
+
+ return devm_add_action_or_reset(&hisi_ptt->pdev->dev,
+ hisi_ptt_unregister_filter_update_notifier,
+ hisi_ptt);
+}
+
/*
* The DMA of PTT trace can only use direct mappings due to some
* hardware restriction. Check whether there is no IOMMU or the
@@ -981,6 +1127,10 @@ static int hisi_ptt_probe(struct pci_dev *pdev,
return ret;
}
+ ret = hisi_ptt_register_filter_update_notifier(hisi_ptt);
+ if (ret)
+ pci_warn(pdev, "failed to register filter update notifier, ret = %d", ret);
+
ret = hisi_ptt_register_pmu(hisi_ptt);
if (ret) {
pci_err(pdev, "failed to register PMU device, ret = %d", ret);
@@ -11,12 +11,15 @@
#include <linux/bits.h>
#include <linux/cpumask.h>
+#include <linux/kfifo.h>
#include <linux/list.h>
#include <linux/mutex.h>
+#include <linux/notifier.h>
#include <linux/pci.h>
#include <linux/perf_event.h>
#include <linux/spinlock.h>
#include <linux/types.h>
+#include <linux/workqueue.h>
#define DRV_NAME "hisi_ptt"
@@ -71,6 +74,11 @@
#define HISI_PTT_WAIT_TRACE_TIMEOUT_US 100UL
#define HISI_PTT_WAIT_POLL_INTERVAL_US 10UL
+/* FIFO size for dynamically updating the PTT trace filter list. */
+#define HISI_PTT_FILTER_UPDATE_FIFO_SIZE 16
+/* Delay time for filter updating work */
+#define HISI_PTT_WORK_DELAY_MS 100UL
+
#define HISI_PCIE_CORE_PORT_ID(devfn) ((PCI_SLOT(devfn) & 0x7) << 1)
/* Definition of the PMU configs */
@@ -143,6 +151,16 @@ struct hisi_ptt_filter_desc {
u16 devid;
};
+/**
+ * struct hisi_ptt_filter_update_info - Information for PTT filter updating
+ * @pdev: the PCI device to update in the filter list
+ * @is_add: adding to the filter or not
+ */
+struct hisi_ptt_filter_update_info {
+ struct pci_dev *pdev;
+ bool is_add;
+};
+
/**
* struct hisi_ptt_pmu_buf - Descriptor of the AUX buffer of PTT trace
* @length: size of the AUX buffer
@@ -170,10 +188,15 @@ struct hisi_ptt_pmu_buf {
* @lower_bdf: the lower BDF range of the PCI devices managed by this PTT device
* @port_filters: the filter list of root ports
* @req_filters: the filter list of requester ID
+ * @filter_lock: lock to protect the filters
* @port_mask: port mask of the managed root ports
+ * @work: delayed work for filter updating
+ * @filter_update_lock: spinlock to protect the filter update fifo
+ * @filter_update_fifo: fifo of the filters waiting to update the filter list
*/
struct hisi_ptt {
struct hisi_ptt_trace_ctrl trace_ctrl;
+ struct notifier_block hisi_ptt_nb;
struct hlist_node hotplug_node;
struct pmu hisi_ptt_pmu;
void __iomem *iobase;
@@ -192,7 +215,19 @@ struct hisi_ptt {
*/
struct list_head port_filters;
struct list_head req_filters;
+ struct mutex filter_lock;
u16 port_mask;
+
+ /*
+ * We use a delayed work here to avoid indefinitely waiting for
+ * the hisi_ptt->mutex which protecting the filter list. The
+ * work will be delayed only if the mutex can not be held,
+ * otherwise no delay will be applied.
+ */
+ struct delayed_work work;
+ spinlock_t filter_update_lock;
+ DECLARE_KFIFO(filter_update_kfifo, struct hisi_ptt_filter_update_info,
+ HISI_PTT_FILTER_UPDATE_FIFO_SIZE);
};
#define to_hisi_ptt(pmu) container_of(pmu, struct hisi_ptt, hisi_ptt_pmu)