diff options
Diffstat (limited to 'drivers/thunderbolt/nhi.c')
-rw-r--r-- | drivers/thunderbolt/nhi.c | 630 |
1 files changed, 630 insertions, 0 deletions
diff --git a/drivers/thunderbolt/nhi.c b/drivers/thunderbolt/nhi.c new file mode 100644 index 0000000..11070ff --- /dev/null +++ b/drivers/thunderbolt/nhi.c @@ -0,0 +1,630 @@ +/* + * 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 <andreas.noever@gmail.com> + */ + +#include <linux/slab.h> +#include <linux/errno.h> +#include <linux/pci.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/dmi.h> + +#include "nhi.h" +#include "nhi_regs.h" + +#define RING_TYPE(ring) ((ring)->is_tx ? "TX ring" : "RX ring") + + +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; + int bit = ring_interrupt_index(ring) & 31; + int mask = 1 << bit; + u32 old, new; + 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 struct tb_ring *ring_alloc(struct tb_nhi *nhi, u32 hop, int size, + bool transmit) +{ + 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->head = 0; + ring->tail = 0; + ring->running = false; + 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) +{ + return ring_alloc(nhi, hop, size, true); +} + +struct tb_ring *ring_alloc_rx(struct tb_nhi *nhi, int hop, int size) +{ + return ring_alloc(nhi, hop, size, false); +} + +/** + * 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); + } + + dma_free_coherent(&ring->nhi->pdev->dev, + ring->size * sizeof(*ring->descriptors), + ring->descriptors, ring->descriptors_dma); + + ring->descriptors = 0; + 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 and ring_stop). 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 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. + */ + devm_free_irq(&nhi->pdev->dev, nhi->pdev->irq, nhi); + flush_work(&nhi->interrupt_work); + mutex_destroy(&nhi->lock); +} + +static int nhi_probe(struct pci_dev *pdev, const struct pci_device_id *id) +{ + struct tb_nhi *nhi; + int res; + + res = pcim_enable_device(pdev); + if (res) { + dev_err(&pdev->dev, "cannot enable PCI device, aborting\n"); + return res; + } + + res = pci_enable_msi(pdev); + if (res) { + dev_err(&pdev->dev, "cannot enable MSI, 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) + dev_warn(&pdev->dev, "unexpected hop count: %d\n", + nhi->hop_count); + INIT_WORK(&nhi->interrupt_work, nhi_interrupt_work); + + nhi->tx_rings = devm_kzalloc(&pdev->dev, + nhi->hop_count * sizeof(struct tb_ring), + GFP_KERNEL); + nhi->rx_rings = devm_kzalloc(&pdev->dev, + nhi->hop_count * sizeof(struct tb_ring), + GFP_KERNEL); + if (!nhi->tx_rings || !nhi->rx_rings) + return -ENOMEM; + + nhi_disable_interrupts(nhi); /* In case someone left them on. */ + res = devm_request_irq(&pdev->dev, pdev->irq, nhi_msi, + IRQF_NO_SUSPEND, /* must work during _noirq */ + "thunderbolt", nhi); + if (res) { + dev_err(&pdev->dev, "request_irq failed, aborting\n"); + return res; + } + + mutex_init(&nhi->lock); + + pci_set_master(pdev); + + /* magic value - clock related? */ + iowrite32(3906250 / 10000, nhi->iobase + 0x38c00); + + pci_set_drvdata(pdev, nhi); + + return 0; +} + +static void nhi_remove(struct pci_dev *pdev) +{ + struct tb_nhi *nhi = pci_get_drvdata(pdev); + nhi_shutdown(nhi); +} + +struct pci_device_id nhi_ids[] = { + /* + * We have to specify class, the TB bridges use the same device and + * vendor (sub)id. + */ + { + .class = PCI_CLASS_SYSTEM_OTHER << 8, .class_mask = ~0, + .vendor = PCI_VENDOR_ID_INTEL, .device = 0x1547, + .subvendor = 0x2222, .subdevice = 0x1111, + }, + { + .class = PCI_CLASS_SYSTEM_OTHER << 8, .class_mask = ~0, + .vendor = PCI_VENDOR_ID_INTEL, .device = 0x156c, + .subvendor = 0x2222, .subdevice = 0x1111, + }, + { 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, +}; + +static int __init nhi_init(void) +{ + if (!dmi_match(DMI_BOARD_VENDOR, "Apple Inc.")) + return -ENOSYS; + return pci_register_driver(&nhi_driver); +} + +static void __exit nhi_unload(void) +{ + pci_unregister_driver(&nhi_driver); +} + +module_init(nhi_init); +module_exit(nhi_unload); |