/* * Thunderbolt Cactus Ridge driver - NHI driver * * The NHI (native host interface) is the pci device that allows us to send and * receive frames from the thunderbolt bus. * * Copyright (c) 2014 Andreas Noever */ #include #include #include #include #include #include #include #include "nhi.h" #include "nhi_regs.h" #include "tb.h" #define RING_TYPE(ring) ((ring)->is_tx ? "TX ring" : "RX ring") /* * Minimal number of vectors when we use MSI-X. Two for control channel * Rx/Tx and the rest four are for cross domain DMA paths. */ #define MSIX_MIN_VECS 6 #define MSIX_MAX_VECS 16 static int ring_interrupt_index(struct tb_ring *ring) { int bit = ring->hop; if (!ring->is_tx) bit += ring->nhi->hop_count; return bit; } /** * ring_interrupt_active() - activate/deactivate interrupts for a single ring * * ring->nhi->lock must be held. */ static void ring_interrupt_active(struct tb_ring *ring, bool active) { int reg = REG_RING_INTERRUPT_BASE + ring_interrupt_index(ring) / 32 * 4; int bit = ring_interrupt_index(ring) & 31; int mask = 1 << bit; u32 old, new; if (ring->irq > 0) { u32 step, shift, ivr, misc; void __iomem *ivr_base; int index; if (ring->is_tx) index = ring->hop; else index = ring->hop + ring->nhi->hop_count; /* * Ask the hardware to clear interrupt status bits automatically * since we already know which interrupt was triggered. */ misc = ioread32(ring->nhi->iobase + REG_DMA_MISC); if (!(misc & REG_DMA_MISC_INT_AUTO_CLEAR)) { misc |= REG_DMA_MISC_INT_AUTO_CLEAR; iowrite32(misc, ring->nhi->iobase + REG_DMA_MISC); } ivr_base = ring->nhi->iobase + REG_INT_VEC_ALLOC_BASE; step = index / REG_INT_VEC_ALLOC_REGS * REG_INT_VEC_ALLOC_BITS; shift = index % REG_INT_VEC_ALLOC_REGS * REG_INT_VEC_ALLOC_BITS; ivr = ioread32(ivr_base + step); ivr &= ~(REG_INT_VEC_ALLOC_MASK << shift); if (active) ivr |= ring->vector << shift; iowrite32(ivr, ivr_base + step); } old = ioread32(ring->nhi->iobase + reg); if (active) new = old | mask; else new = old & ~mask; dev_info(&ring->nhi->pdev->dev, "%s interrupt at register %#x bit %d (%#x -> %#x)\n", active ? "enabling" : "disabling", reg, bit, old, new); if (new == old) dev_WARN(&ring->nhi->pdev->dev, "interrupt for %s %d is already %s\n", RING_TYPE(ring), ring->hop, active ? "enabled" : "disabled"); iowrite32(new, ring->nhi->iobase + reg); } /** * nhi_disable_interrupts() - disable interrupts for all rings * * Use only during init and shutdown. */ static void nhi_disable_interrupts(struct tb_nhi *nhi) { int i = 0; /* disable interrupts */ for (i = 0; i < RING_INTERRUPT_REG_COUNT(nhi); i++) iowrite32(0, nhi->iobase + REG_RING_INTERRUPT_BASE + 4 * i); /* clear interrupt status bits */ for (i = 0; i < RING_NOTIFY_REG_COUNT(nhi); i++) ioread32(nhi->iobase + REG_RING_NOTIFY_BASE + 4 * i); } /* ring helper methods */ static void __iomem *ring_desc_base(struct tb_ring *ring) { void __iomem *io = ring->nhi->iobase; io += ring->is_tx ? REG_TX_RING_BASE : REG_RX_RING_BASE; io += ring->hop * 16; return io; } static void __iomem *ring_options_base(struct tb_ring *ring) { void __iomem *io = ring->nhi->iobase; io += ring->is_tx ? REG_TX_OPTIONS_BASE : REG_RX_OPTIONS_BASE; io += ring->hop * 32; return io; } static void ring_iowrite16desc(struct tb_ring *ring, u32 value, u32 offset) { iowrite16(value, ring_desc_base(ring) + offset); } static void ring_iowrite32desc(struct tb_ring *ring, u32 value, u32 offset) { iowrite32(value, ring_desc_base(ring) + offset); } static void ring_iowrite64desc(struct tb_ring *ring, u64 value, u32 offset) { iowrite32(value, ring_desc_base(ring) + offset); iowrite32(value >> 32, ring_desc_base(ring) + offset + 4); } static void ring_iowrite32options(struct tb_ring *ring, u32 value, u32 offset) { iowrite32(value, ring_options_base(ring) + offset); } static bool ring_full(struct tb_ring *ring) { return ((ring->head + 1) % ring->size) == ring->tail; } static bool ring_empty(struct tb_ring *ring) { return ring->head == ring->tail; } /** * ring_write_descriptors() - post frames from ring->queue to the controller * * ring->lock is held. */ static void ring_write_descriptors(struct tb_ring *ring) { struct ring_frame *frame, *n; struct ring_desc *descriptor; list_for_each_entry_safe(frame, n, &ring->queue, list) { if (ring_full(ring)) break; list_move_tail(&frame->list, &ring->in_flight); descriptor = &ring->descriptors[ring->head]; descriptor->phys = frame->buffer_phy; descriptor->time = 0; descriptor->flags = RING_DESC_POSTED | RING_DESC_INTERRUPT; if (ring->is_tx) { descriptor->length = frame->size; descriptor->eof = frame->eof; descriptor->sof = frame->sof; } ring->head = (ring->head + 1) % ring->size; ring_iowrite16desc(ring, ring->head, ring->is_tx ? 10 : 8); } } /** * ring_work() - progress completed frames * * If the ring is shutting down then all frames are marked as canceled and * their callbacks are invoked. * * Otherwise we collect all completed frame from the ring buffer, write new * frame to the ring buffer and invoke the callbacks for the completed frames. */ static void ring_work(struct work_struct *work) { struct tb_ring *ring = container_of(work, typeof(*ring), work); struct ring_frame *frame; bool canceled = false; LIST_HEAD(done); mutex_lock(&ring->lock); if (!ring->running) { /* Move all frames to done and mark them as canceled. */ list_splice_tail_init(&ring->in_flight, &done); list_splice_tail_init(&ring->queue, &done); canceled = true; goto invoke_callback; } while (!ring_empty(ring)) { if (!(ring->descriptors[ring->tail].flags & RING_DESC_COMPLETED)) break; frame = list_first_entry(&ring->in_flight, typeof(*frame), list); list_move_tail(&frame->list, &done); if (!ring->is_tx) { frame->size = ring->descriptors[ring->tail].length; frame->eof = ring->descriptors[ring->tail].eof; frame->sof = ring->descriptors[ring->tail].sof; frame->flags = ring->descriptors[ring->tail].flags; if (frame->sof != 0) dev_WARN(&ring->nhi->pdev->dev, "%s %d got unexpected SOF: %#x\n", RING_TYPE(ring), ring->hop, frame->sof); /* * known flags: * raw not enabled, interupt not set: 0x2=0010 * raw enabled: 0xa=1010 * raw not enabled: 0xb=1011 * partial frame (>MAX_FRAME_SIZE): 0xe=1110 */ if (frame->flags != 0xa) dev_WARN(&ring->nhi->pdev->dev, "%s %d got unexpected flags: %#x\n", RING_TYPE(ring), ring->hop, frame->flags); } ring->tail = (ring->tail + 1) % ring->size; } ring_write_descriptors(ring); invoke_callback: mutex_unlock(&ring->lock); /* allow callbacks to schedule new work */ while (!list_empty(&done)) { frame = list_first_entry(&done, typeof(*frame), list); /* * The callback may reenqueue or delete frame. * Do not hold on to it. */ list_del_init(&frame->list); frame->callback(ring, frame, canceled); } } int __ring_enqueue(struct tb_ring *ring, struct ring_frame *frame) { int ret = 0; mutex_lock(&ring->lock); if (ring->running) { list_add_tail(&frame->list, &ring->queue); ring_write_descriptors(ring); } else { ret = -ESHUTDOWN; } mutex_unlock(&ring->lock); return ret; } static irqreturn_t ring_msix(int irq, void *data) { struct tb_ring *ring = data; schedule_work(&ring->work); return IRQ_HANDLED; } static int ring_request_msix(struct tb_ring *ring, bool no_suspend) { struct tb_nhi *nhi = ring->nhi; unsigned long irqflags; int ret; if (!nhi->pdev->msix_enabled) return 0; ret = ida_simple_get(&nhi->msix_ida, 0, MSIX_MAX_VECS, GFP_KERNEL); if (ret < 0) return ret; ring->vector = ret; ring->irq = pci_irq_vector(ring->nhi->pdev, ring->vector); if (ring->irq < 0) return ring->irq; irqflags = no_suspend ? IRQF_NO_SUSPEND : 0; return request_irq(ring->irq, ring_msix, irqflags, "thunderbolt", ring); } static void ring_release_msix(struct tb_ring *ring) { if (ring->irq <= 0) return; free_irq(ring->irq, ring); ida_simple_remove(&ring->nhi->msix_ida, ring->vector); ring->vector = 0; ring->irq = 0; } static struct tb_ring *ring_alloc(struct tb_nhi *nhi, u32 hop, int size, bool transmit, unsigned int flags) { struct tb_ring *ring = NULL; dev_info(&nhi->pdev->dev, "allocating %s ring %d of size %d\n", transmit ? "TX" : "RX", hop, size); mutex_lock(&nhi->lock); if (hop >= nhi->hop_count) { dev_WARN(&nhi->pdev->dev, "invalid hop: %d\n", hop); goto err; } if (transmit && nhi->tx_rings[hop]) { dev_WARN(&nhi->pdev->dev, "TX hop %d already allocated\n", hop); goto err; } else if (!transmit && nhi->rx_rings[hop]) { dev_WARN(&nhi->pdev->dev, "RX hop %d already allocated\n", hop); goto err; } ring = kzalloc(sizeof(*ring), GFP_KERNEL); if (!ring) goto err; mutex_init(&ring->lock); INIT_LIST_HEAD(&ring->queue); INIT_LIST_HEAD(&ring->in_flight); INIT_WORK(&ring->work, ring_work); ring->nhi = nhi; ring->hop = hop; ring->is_tx = transmit; ring->size = size; ring->flags = flags; ring->head = 0; ring->tail = 0; ring->running = false; if (ring_request_msix(ring, flags & RING_FLAG_NO_SUSPEND)) goto err; ring->descriptors = dma_alloc_coherent(&ring->nhi->pdev->dev, size * sizeof(*ring->descriptors), &ring->descriptors_dma, GFP_KERNEL | __GFP_ZERO); if (!ring->descriptors) goto err; if (transmit) nhi->tx_rings[hop] = ring; else nhi->rx_rings[hop] = ring; mutex_unlock(&nhi->lock); return ring; err: if (ring) mutex_destroy(&ring->lock); kfree(ring); mutex_unlock(&nhi->lock); return NULL; } struct tb_ring *ring_alloc_tx(struct tb_nhi *nhi, int hop, int size, unsigned int flags) { return ring_alloc(nhi, hop, size, true, flags); } struct tb_ring *ring_alloc_rx(struct tb_nhi *nhi, int hop, int size, unsigned int flags) { return ring_alloc(nhi, hop, size, false, flags); } /** * ring_start() - enable a ring * * Must not be invoked in parallel with ring_stop(). */ void ring_start(struct tb_ring *ring) { mutex_lock(&ring->nhi->lock); mutex_lock(&ring->lock); if (ring->running) { dev_WARN(&ring->nhi->pdev->dev, "ring already started\n"); goto err; } dev_info(&ring->nhi->pdev->dev, "starting %s %d\n", RING_TYPE(ring), ring->hop); ring_iowrite64desc(ring, ring->descriptors_dma, 0); if (ring->is_tx) { ring_iowrite32desc(ring, ring->size, 12); ring_iowrite32options(ring, 0, 4); /* time releated ? */ ring_iowrite32options(ring, RING_FLAG_ENABLE | RING_FLAG_RAW, 0); } else { ring_iowrite32desc(ring, (TB_FRAME_SIZE << 16) | ring->size, 12); ring_iowrite32options(ring, 0xffffffff, 4); /* SOF EOF mask */ ring_iowrite32options(ring, RING_FLAG_ENABLE | RING_FLAG_RAW, 0); } ring_interrupt_active(ring, true); ring->running = true; err: mutex_unlock(&ring->lock); mutex_unlock(&ring->nhi->lock); } /** * ring_stop() - shutdown a ring * * Must not be invoked from a callback. * * This method will disable the ring. Further calls to ring_tx/ring_rx will * return -ESHUTDOWN until ring_stop has been called. * * All enqueued frames will be canceled and their callbacks will be executed * with frame->canceled set to true (on the callback thread). This method * returns only after all callback invocations have finished. */ void ring_stop(struct tb_ring *ring) { mutex_lock(&ring->nhi->lock); mutex_lock(&ring->lock); dev_info(&ring->nhi->pdev->dev, "stopping %s %d\n", RING_TYPE(ring), ring->hop); if (!ring->running) { dev_WARN(&ring->nhi->pdev->dev, "%s %d already stopped\n", RING_TYPE(ring), ring->hop); goto err; } ring_interrupt_active(ring, false); ring_iowrite32options(ring, 0, 0); ring_iowrite64desc(ring, 0, 0); ring_iowrite16desc(ring, 0, ring->is_tx ? 10 : 8); ring_iowrite32desc(ring, 0, 12); ring->head = 0; ring->tail = 0; ring->running = false; err: mutex_unlock(&ring->lock); mutex_unlock(&ring->nhi->lock); /* * schedule ring->work to invoke callbacks on all remaining frames. */ schedule_work(&ring->work); flush_work(&ring->work); } /* * ring_free() - free ring * * When this method returns all invocations of ring->callback will have * finished. * * Ring must be stopped. * * Must NOT be called from ring_frame->callback! */ void ring_free(struct tb_ring *ring) { mutex_lock(&ring->nhi->lock); /* * Dissociate the ring from the NHI. This also ensures that * nhi_interrupt_work cannot reschedule ring->work. */ if (ring->is_tx) ring->nhi->tx_rings[ring->hop] = NULL; else ring->nhi->rx_rings[ring->hop] = NULL; if (ring->running) { dev_WARN(&ring->nhi->pdev->dev, "%s %d still running\n", RING_TYPE(ring), ring->hop); } ring_release_msix(ring); dma_free_coherent(&ring->nhi->pdev->dev, ring->size * sizeof(*ring->descriptors), ring->descriptors, ring->descriptors_dma); ring->descriptors = NULL; ring->descriptors_dma = 0; dev_info(&ring->nhi->pdev->dev, "freeing %s %d\n", RING_TYPE(ring), ring->hop); mutex_unlock(&ring->nhi->lock); /** * ring->work can no longer be scheduled (it is scheduled only * by nhi_interrupt_work, ring_stop and ring_msix). Wait for it * to finish before freeing the ring. */ flush_work(&ring->work); mutex_destroy(&ring->lock); kfree(ring); } static void nhi_interrupt_work(struct work_struct *work) { struct tb_nhi *nhi = container_of(work, typeof(*nhi), interrupt_work); int value = 0; /* Suppress uninitialized usage warning. */ int bit; int hop = -1; int type = 0; /* current interrupt type 0: TX, 1: RX, 2: RX overflow */ struct tb_ring *ring; mutex_lock(&nhi->lock); /* * Starting at REG_RING_NOTIFY_BASE there are three status bitfields * (TX, RX, RX overflow). We iterate over the bits and read a new * dwords as required. The registers are cleared on read. */ for (bit = 0; bit < 3 * nhi->hop_count; bit++) { if (bit % 32 == 0) value = ioread32(nhi->iobase + REG_RING_NOTIFY_BASE + 4 * (bit / 32)); if (++hop == nhi->hop_count) { hop = 0; type++; } if ((value & (1 << (bit % 32))) == 0) continue; if (type == 2) { dev_warn(&nhi->pdev->dev, "RX overflow for ring %d\n", hop); continue; } if (type == 0) ring = nhi->tx_rings[hop]; else ring = nhi->rx_rings[hop]; if (ring == NULL) { dev_warn(&nhi->pdev->dev, "got interrupt for inactive %s ring %d\n", type ? "RX" : "TX", hop); continue; } /* we do not check ring->running, this is done in ring->work */ schedule_work(&ring->work); } mutex_unlock(&nhi->lock); } static irqreturn_t nhi_msi(int irq, void *data) { struct tb_nhi *nhi = data; schedule_work(&nhi->interrupt_work); return IRQ_HANDLED; } static int nhi_suspend_noirq(struct device *dev) { struct pci_dev *pdev = to_pci_dev(dev); struct tb *tb = pci_get_drvdata(pdev); return tb_domain_suspend_noirq(tb); } static int nhi_resume_noirq(struct device *dev) { struct pci_dev *pdev = to_pci_dev(dev); struct tb *tb = pci_get_drvdata(pdev); return tb_domain_resume_noirq(tb); } static void nhi_shutdown(struct tb_nhi *nhi) { int i; dev_info(&nhi->pdev->dev, "shutdown\n"); for (i = 0; i < nhi->hop_count; i++) { if (nhi->tx_rings[i]) dev_WARN(&nhi->pdev->dev, "TX ring %d is still active\n", i); if (nhi->rx_rings[i]) dev_WARN(&nhi->pdev->dev, "RX ring %d is still active\n", i); } nhi_disable_interrupts(nhi); /* * We have to release the irq before calling flush_work. Otherwise an * already executing IRQ handler could call schedule_work again. */ if (!nhi->pdev->msix_enabled) { devm_free_irq(&nhi->pdev->dev, nhi->pdev->irq, nhi); flush_work(&nhi->interrupt_work); } mutex_destroy(&nhi->lock); ida_destroy(&nhi->msix_ida); } static int nhi_init_msi(struct tb_nhi *nhi) { struct pci_dev *pdev = nhi->pdev; int res, irq, nvec; /* In case someone left them on. */ nhi_disable_interrupts(nhi); ida_init(&nhi->msix_ida); /* * The NHI has 16 MSI-X vectors or a single MSI. We first try to * get all MSI-X vectors and if we succeed, each ring will have * one MSI-X. If for some reason that does not work out, we * fallback to a single MSI. */ nvec = pci_alloc_irq_vectors(pdev, MSIX_MIN_VECS, MSIX_MAX_VECS, PCI_IRQ_MSIX); if (nvec < 0) { nvec = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI); if (nvec < 0) return nvec; INIT_WORK(&nhi->interrupt_work, nhi_interrupt_work); irq = pci_irq_vector(nhi->pdev, 0); if (irq < 0) return irq; res = devm_request_irq(&pdev->dev, irq, nhi_msi, IRQF_NO_SUSPEND, "thunderbolt", nhi); if (res) { dev_err(&pdev->dev, "request_irq failed, aborting\n"); return res; } } return 0; } static int nhi_probe(struct pci_dev *pdev, const struct pci_device_id *id) { struct tb_nhi *nhi; struct tb *tb; int res; res = pcim_enable_device(pdev); if (res) { dev_err(&pdev->dev, "cannot enable PCI device, aborting\n"); return res; } res = pcim_iomap_regions(pdev, 1 << 0, "thunderbolt"); if (res) { dev_err(&pdev->dev, "cannot obtain PCI resources, aborting\n"); return res; } nhi = devm_kzalloc(&pdev->dev, sizeof(*nhi), GFP_KERNEL); if (!nhi) return -ENOMEM; nhi->pdev = pdev; /* cannot fail - table is allocated bin pcim_iomap_regions */ nhi->iobase = pcim_iomap_table(pdev)[0]; nhi->hop_count = ioread32(nhi->iobase + REG_HOP_COUNT) & 0x3ff; if (nhi->hop_count != 12 && nhi->hop_count != 32) dev_warn(&pdev->dev, "unexpected hop count: %d\n", nhi->hop_count); nhi->tx_rings = devm_kcalloc(&pdev->dev, nhi->hop_count, sizeof(*nhi->tx_rings), GFP_KERNEL); nhi->rx_rings = devm_kcalloc(&pdev->dev, nhi->hop_count, sizeof(*nhi->rx_rings), GFP_KERNEL); if (!nhi->tx_rings || !nhi->rx_rings) return -ENOMEM; res = nhi_init_msi(nhi); if (res) { dev_err(&pdev->dev, "cannot enable MSI, aborting\n"); return res; } mutex_init(&nhi->lock); pci_set_master(pdev); /* magic value - clock related? */ iowrite32(3906250 / 10000, nhi->iobase + 0x38c00); dev_info(&nhi->pdev->dev, "NHI initialized, starting thunderbolt\n"); tb = tb_probe(nhi); if (!tb) return -ENODEV; res = tb_domain_add(tb); if (res) { /* * At this point the RX/TX rings might already have been * activated. Do a proper shutdown. */ tb_domain_put(tb); nhi_shutdown(nhi); return -EIO; } pci_set_drvdata(pdev, tb); return 0; } static void nhi_remove(struct pci_dev *pdev) { struct tb *tb = pci_get_drvdata(pdev); struct tb_nhi *nhi = tb->nhi; tb_domain_remove(tb); nhi_shutdown(nhi); } /* * The tunneled pci bridges are siblings of us. Use resume_noirq to reenable * the tunnels asap. A corresponding pci quirk blocks the downstream bridges * resume_noirq until we are done. */ static const struct dev_pm_ops nhi_pm_ops = { .suspend_noirq = nhi_suspend_noirq, .resume_noirq = nhi_resume_noirq, .freeze_noirq = nhi_suspend_noirq, /* * we just disable hotplug, the * pci-tunnels stay alive. */ .restore_noirq = nhi_resume_noirq, }; static struct pci_device_id nhi_ids[] = { /* * We have to specify class, the TB bridges use the same device and * vendor (sub)id on gen 1 and gen 2 controllers. */ { .class = PCI_CLASS_SYSTEM_OTHER << 8, .class_mask = ~0, .vendor = PCI_VENDOR_ID_INTEL, .device = PCI_DEVICE_ID_INTEL_LIGHT_RIDGE, .subvendor = 0x2222, .subdevice = 0x1111, }, { .class = PCI_CLASS_SYSTEM_OTHER << 8, .class_mask = ~0, .vendor = PCI_VENDOR_ID_INTEL, .device = PCI_DEVICE_ID_INTEL_CACTUS_RIDGE_4C, .subvendor = 0x2222, .subdevice = 0x1111, }, { .class = PCI_CLASS_SYSTEM_OTHER << 8, .class_mask = ~0, .vendor = PCI_VENDOR_ID_INTEL, .device = PCI_DEVICE_ID_INTEL_FALCON_RIDGE_2C_NHI, .subvendor = PCI_ANY_ID, .subdevice = PCI_ANY_ID, }, { .class = PCI_CLASS_SYSTEM_OTHER << 8, .class_mask = ~0, .vendor = PCI_VENDOR_ID_INTEL, .device = PCI_DEVICE_ID_INTEL_FALCON_RIDGE_4C_NHI, .subvendor = PCI_ANY_ID, .subdevice = PCI_ANY_ID, }, /* Thunderbolt 3 */ { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_2C_NHI) }, { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_4C_NHI) }, { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_USBONLY_NHI) }, { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_LP_NHI) }, { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_LP_USBONLY_NHI) }, { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_2C_NHI) }, { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_4C_NHI) }, { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_USBONLY_NHI) }, { 0,} }; MODULE_DEVICE_TABLE(pci, nhi_ids); MODULE_LICENSE("GPL"); static struct pci_driver nhi_driver = { .name = "thunderbolt", .id_table = nhi_ids, .probe = nhi_probe, .remove = nhi_remove, .driver.pm = &nhi_pm_ops, }; static int __init nhi_init(void) { int ret; if (!dmi_match(DMI_BOARD_VENDOR, "Apple Inc.")) return -ENOSYS; ret = tb_domain_init(); if (ret) return ret; ret = pci_register_driver(&nhi_driver); if (ret) tb_domain_exit(); return ret; } static void __exit nhi_unload(void) { pci_unregister_driver(&nhi_driver); tb_domain_exit(); } module_init(nhi_init); module_exit(nhi_unload);