--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * PCIe bandwidth controller
+ *
+ *
+ * Copyright (C) 2019 Dell Inc
+ * Copyright (C) 2023-2024 Intel Corporation
+ *
+ * This service port driver hooks into the Bandwidth Notification interrupt
+ * watching for changes or links becoming degraded in operation. It updates
+ * the cached Current Link Speed that is exposed to user space through sysfs.
+ */
+
+#define dev_fmt(fmt) "bwctrl: " fmt
+
+#include <linux/atomic.h>
+#include <linux/cleanup.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/pci.h>
+#include <linux/rwsem.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "../pci.h"
+#include "portdrv.h"
+
+/**
+ * struct pcie_bwctrl_data - PCIe bandwidth controller
+ * @lbms_count: Count for LBMS (since last reset)
+ */
+struct pcie_bwctrl_data {
+ atomic_t lbms_count;
+};
+
+/* Prevents port removal during LBMS count accessors */
+static DECLARE_RWSEM(pcie_bwctrl_lbms_rwsem);
+
+static void pcie_bwnotif_enable(struct pcie_device *srv)
+{
+ struct pcie_bwctrl_data *data = srv->port->link_bwctrl;
+ struct pci_dev *port = srv->port;
+ u16 link_status;
+ int ret;
+
+ /* Count LBMS seen so far as one */
+ ret = pcie_capability_read_word(port, PCI_EXP_LNKSTA, &link_status);
+ if (ret == PCIBIOS_SUCCESSFUL && link_status & PCI_EXP_LNKSTA_LBMS)
+ atomic_inc(&data->lbms_count);
+
+ pcie_capability_set_word(port, PCI_EXP_LNKCTL,
+ PCI_EXP_LNKCTL_LBMIE | PCI_EXP_LNKCTL_LABIE);
+ pcie_capability_write_word(port, PCI_EXP_LNKSTA,
+ PCI_EXP_LNKSTA_LBMS | PCI_EXP_LNKSTA_LABS);
+
+ /*
+ * Update after enabling notifications & clearing status bits ensures
+ * link speed is up to date.
+ */
+ pcie_update_link_speed(port->subordinate);
+}
+
+static void pcie_bwnotif_disable(struct pci_dev *port)
+{
+ pcie_capability_clear_word(port, PCI_EXP_LNKCTL,
+ PCI_EXP_LNKCTL_LBMIE | PCI_EXP_LNKCTL_LABIE);
+}
+
+static irqreturn_t pcie_bwnotif_irq(int irq, void *context)
+{
+ struct pcie_device *srv = context;
+ struct pcie_bwctrl_data *data = srv->port->link_bwctrl;
+ struct pci_dev *port = srv->port;
+ u16 link_status, events;
+ int ret;
+
+ ret = pcie_capability_read_word(port, PCI_EXP_LNKSTA, &link_status);
+ if (ret != PCIBIOS_SUCCESSFUL)
+ return IRQ_NONE;
+
+ events = link_status & (PCI_EXP_LNKSTA_LBMS | PCI_EXP_LNKSTA_LABS);
+ if (!events)
+ return IRQ_NONE;
+
+ if (events & PCI_EXP_LNKSTA_LBMS)
+ atomic_inc(&data->lbms_count);
+
+ pcie_capability_write_word(port, PCI_EXP_LNKSTA, events);
+
+ /*
+ * Interrupts will not be triggered from any further Link Speed
+ * change until LBMS is cleared by the write. Therefore, re-read the
+ * speed (inside pcie_update_link_speed()) after LBMS has been
+ * cleared to avoid missing link speed changes.
+ */
+ pcie_update_link_speed(port->subordinate);
+
+ return IRQ_HANDLED;
+}
+
+void pcie_reset_lbms_count(struct pci_dev *port)
+{
+ struct pcie_bwctrl_data *data;
+
+ guard(rwsem_read)(&pcie_bwctrl_lbms_rwsem);
+ data = port->link_bwctrl;
+ if (data)
+ atomic_set(&data->lbms_count, 0);
+ else
+ pcie_capability_write_word(port, PCI_EXP_LNKSTA,
+ PCI_EXP_LNKSTA_LBMS);
+}
+
+int pcie_lbms_count(struct pci_dev *port, unsigned long *val)
+{
+ struct pcie_bwctrl_data *data;
+
+ guard(rwsem_read)(&pcie_bwctrl_lbms_rwsem);
+ data = port->link_bwctrl;
+ if (!data)
+ return -ENOTTY;
+
+ *val = atomic_read(&data->lbms_count);
+
+ return 0;
+}
+
+static int pcie_bwnotif_probe(struct pcie_device *srv)
+{
+ struct pci_dev *port = srv->port;
+ int ret;
+
+ struct pcie_bwctrl_data *data = devm_kzalloc(&srv->device,
+ sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ ret = devm_request_irq(&srv->device, srv->irq, pcie_bwnotif_irq,
+ IRQF_SHARED, "PCIe bwctrl", srv);
+ if (ret)
+ return ret;
+
+ scoped_guard(rwsem_write, &pcie_bwctrl_lbms_rwsem) {
+ port->link_bwctrl = no_free_ptr(data);
+ pcie_bwnotif_enable(srv);
+ }
+
+ pci_dbg(port, "enabled with IRQ %d\n", srv->irq);
+
+ return 0;
+}
+
+static void pcie_bwnotif_remove(struct pcie_device *srv)
+{
+ pcie_bwnotif_disable(srv->port);
+ scoped_guard(rwsem_write, &pcie_bwctrl_lbms_rwsem)
+ srv->port->link_bwctrl = NULL;
+}
+
+static int pcie_bwnotif_suspend(struct pcie_device *srv)
+{
+ pcie_bwnotif_disable(srv->port);
+ return 0;
+}
+
+static int pcie_bwnotif_resume(struct pcie_device *srv)
+{
+ pcie_bwnotif_enable(srv);
+ return 0;
+}
+
+static struct pcie_port_service_driver pcie_bwctrl_driver = {
+ .name = "pcie_bwctrl",
+ .port_type = PCIE_ANY_PORT,
+ .service = PCIE_PORT_SERVICE_BWCTRL,
+ .probe = pcie_bwnotif_probe,
+ .suspend = pcie_bwnotif_suspend,
+ .resume = pcie_bwnotif_resume,
+ .remove = pcie_bwnotif_remove,
+};
+
+int __init pcie_bwctrl_init(void)
+{
+ return pcie_port_service_register(&pcie_bwctrl_driver);
+}
*/
if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP |
- PCIE_PORT_SERVICE_BWNOTIF)) {
+ PCIE_PORT_SERVICE_BWCTRL)) {
pcie_capability_read_word(dev, PCI_EXP_FLAGS, ®16);
*pme = FIELD_GET(PCI_EXP_FLAGS_IRQ, reg16);
nvec = *pme + 1;
/* PME, hotplug and bandwidth notification share an MSI/MSI-X vector */
if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP |
- PCIE_PORT_SERVICE_BWNOTIF)) {
+ PCIE_PORT_SERVICE_BWCTRL)) {
pcie_irq = pci_irq_vector(dev, pme);
irqs[PCIE_PORT_SERVICE_PME_SHIFT] = pcie_irq;
irqs[PCIE_PORT_SERVICE_HP_SHIFT] = pcie_irq;
- irqs[PCIE_PORT_SERVICE_BWNOTIF_SHIFT] = pcie_irq;
+ irqs[PCIE_PORT_SERVICE_BWCTRL_SHIFT] = pcie_irq;
}
if (mask & PCIE_PORT_SERVICE_AER)
pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &linkcap);
if (linkcap & PCI_EXP_LNKCAP_LBNC)
- services |= PCIE_PORT_SERVICE_BWNOTIF;
+ services |= PCIE_PORT_SERVICE_BWCTRL;
}
return services;
pcie_aer_init();
pcie_pme_init();
pcie_dpc_init();
+ pcie_bwctrl_init();
pcie_hp_init();
}
projects / linux.git / commitdiff