diff options
Diffstat (limited to 'drivers/dma/plx_dma.c')
| -rw-r--r-- | drivers/dma/plx_dma.c | 636 |
1 files changed, 636 insertions, 0 deletions
diff --git a/drivers/dma/plx_dma.c b/drivers/dma/plx_dma.c new file mode 100644 index 000000000..12725fa16 --- /dev/null +++ b/drivers/dma/plx_dma.c @@ -0,0 +1,636 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Microsemi Switchtec(tm) PCIe Management Driver + * Copyright (c) 2019, Logan Gunthorpe <logang@deltatee.com> + * Copyright (c) 2019, GigaIO Networks, Inc + */ + +#include "dmaengine.h" + +#include <linux/circ_buf.h> +#include <linux/dmaengine.h> +#include <linux/kref.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/pci.h> + +MODULE_DESCRIPTION("PLX ExpressLane PEX PCI Switch DMA Engine"); +MODULE_VERSION("0.1"); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Logan Gunthorpe"); + +#define PLX_REG_DESC_RING_ADDR 0x214 +#define PLX_REG_DESC_RING_ADDR_HI 0x218 +#define PLX_REG_DESC_RING_NEXT_ADDR 0x21C +#define PLX_REG_DESC_RING_COUNT 0x220 +#define PLX_REG_DESC_RING_LAST_ADDR 0x224 +#define PLX_REG_DESC_RING_LAST_SIZE 0x228 +#define PLX_REG_PREF_LIMIT 0x234 +#define PLX_REG_CTRL 0x238 +#define PLX_REG_CTRL2 0x23A +#define PLX_REG_INTR_CTRL 0x23C +#define PLX_REG_INTR_STATUS 0x23E + +#define PLX_REG_PREF_LIMIT_PREF_FOUR 8 + +#define PLX_REG_CTRL_GRACEFUL_PAUSE BIT(0) +#define PLX_REG_CTRL_ABORT BIT(1) +#define PLX_REG_CTRL_WRITE_BACK_EN BIT(2) +#define PLX_REG_CTRL_START BIT(3) +#define PLX_REG_CTRL_RING_STOP_MODE BIT(4) +#define PLX_REG_CTRL_DESC_MODE_BLOCK (0 << 5) +#define PLX_REG_CTRL_DESC_MODE_ON_CHIP (1 << 5) +#define PLX_REG_CTRL_DESC_MODE_OFF_CHIP (2 << 5) +#define PLX_REG_CTRL_DESC_INVALID BIT(8) +#define PLX_REG_CTRL_GRACEFUL_PAUSE_DONE BIT(9) +#define PLX_REG_CTRL_ABORT_DONE BIT(10) +#define PLX_REG_CTRL_IMM_PAUSE_DONE BIT(12) +#define PLX_REG_CTRL_IN_PROGRESS BIT(30) + +#define PLX_REG_CTRL_RESET_VAL (PLX_REG_CTRL_DESC_INVALID | \ + PLX_REG_CTRL_GRACEFUL_PAUSE_DONE | \ + PLX_REG_CTRL_ABORT_DONE | \ + PLX_REG_CTRL_IMM_PAUSE_DONE) + +#define PLX_REG_CTRL_START_VAL (PLX_REG_CTRL_WRITE_BACK_EN | \ + PLX_REG_CTRL_DESC_MODE_OFF_CHIP | \ + PLX_REG_CTRL_START | \ + PLX_REG_CTRL_RESET_VAL) + +#define PLX_REG_CTRL2_MAX_TXFR_SIZE_64B 0 +#define PLX_REG_CTRL2_MAX_TXFR_SIZE_128B 1 +#define PLX_REG_CTRL2_MAX_TXFR_SIZE_256B 2 +#define PLX_REG_CTRL2_MAX_TXFR_SIZE_512B 3 +#define PLX_REG_CTRL2_MAX_TXFR_SIZE_1KB 4 +#define PLX_REG_CTRL2_MAX_TXFR_SIZE_2KB 5 +#define PLX_REG_CTRL2_MAX_TXFR_SIZE_4B 7 + +#define PLX_REG_INTR_CRTL_ERROR_EN BIT(0) +#define PLX_REG_INTR_CRTL_INV_DESC_EN BIT(1) +#define PLX_REG_INTR_CRTL_ABORT_DONE_EN BIT(3) +#define PLX_REG_INTR_CRTL_PAUSE_DONE_EN BIT(4) +#define PLX_REG_INTR_CRTL_IMM_PAUSE_DONE_EN BIT(5) + +#define PLX_REG_INTR_STATUS_ERROR BIT(0) +#define PLX_REG_INTR_STATUS_INV_DESC BIT(1) +#define PLX_REG_INTR_STATUS_DESC_DONE BIT(2) +#define PLX_REG_INTR_CRTL_ABORT_DONE BIT(3) + +struct plx_dma_hw_std_desc { + __le32 flags_and_size; + __le16 dst_addr_hi; + __le16 src_addr_hi; + __le32 dst_addr_lo; + __le32 src_addr_lo; +}; + +#define PLX_DESC_SIZE_MASK 0x7ffffff +#define PLX_DESC_FLAG_VALID BIT(31) +#define PLX_DESC_FLAG_INT_WHEN_DONE BIT(30) + +#define PLX_DESC_WB_SUCCESS BIT(30) +#define PLX_DESC_WB_RD_FAIL BIT(29) +#define PLX_DESC_WB_WR_FAIL BIT(28) + +#define PLX_DMA_RING_COUNT 2048 + +struct plx_dma_desc { + struct dma_async_tx_descriptor txd; + struct plx_dma_hw_std_desc *hw; + u32 orig_size; +}; + +struct plx_dma_dev { + struct dma_device dma_dev; + struct dma_chan dma_chan; + struct pci_dev __rcu *pdev; + void __iomem *bar; + struct tasklet_struct desc_task; + + spinlock_t ring_lock; + bool ring_active; + int head; + int tail; + struct plx_dma_hw_std_desc *hw_ring; + dma_addr_t hw_ring_dma; + struct plx_dma_desc **desc_ring; +}; + +static struct plx_dma_dev *chan_to_plx_dma_dev(struct dma_chan *c) +{ + return container_of(c, struct plx_dma_dev, dma_chan); +} + +static struct plx_dma_desc *to_plx_desc(struct dma_async_tx_descriptor *txd) +{ + return container_of(txd, struct plx_dma_desc, txd); +} + +static struct plx_dma_desc *plx_dma_get_desc(struct plx_dma_dev *plxdev, int i) +{ + return plxdev->desc_ring[i & (PLX_DMA_RING_COUNT - 1)]; +} + +static void plx_dma_process_desc(struct plx_dma_dev *plxdev) +{ + struct dmaengine_result res; + struct plx_dma_desc *desc; + u32 flags; + + spin_lock(&plxdev->ring_lock); + + while (plxdev->tail != plxdev->head) { + desc = plx_dma_get_desc(plxdev, plxdev->tail); + + flags = le32_to_cpu(READ_ONCE(desc->hw->flags_and_size)); + + if (flags & PLX_DESC_FLAG_VALID) + break; + + res.residue = desc->orig_size - (flags & PLX_DESC_SIZE_MASK); + + if (flags & PLX_DESC_WB_SUCCESS) + res.result = DMA_TRANS_NOERROR; + else if (flags & PLX_DESC_WB_WR_FAIL) + res.result = DMA_TRANS_WRITE_FAILED; + else + res.result = DMA_TRANS_READ_FAILED; + + dma_cookie_complete(&desc->txd); + dma_descriptor_unmap(&desc->txd); + dmaengine_desc_get_callback_invoke(&desc->txd, &res); + desc->txd.callback = NULL; + desc->txd.callback_result = NULL; + + plxdev->tail++; + } + + spin_unlock(&plxdev->ring_lock); +} + +static void plx_dma_abort_desc(struct plx_dma_dev *plxdev) +{ + struct dmaengine_result res; + struct plx_dma_desc *desc; + + plx_dma_process_desc(plxdev); + + spin_lock_bh(&plxdev->ring_lock); + + while (plxdev->tail != plxdev->head) { + desc = plx_dma_get_desc(plxdev, plxdev->tail); + + res.residue = desc->orig_size; + res.result = DMA_TRANS_ABORTED; + + dma_cookie_complete(&desc->txd); + dma_descriptor_unmap(&desc->txd); + dmaengine_desc_get_callback_invoke(&desc->txd, &res); + desc->txd.callback = NULL; + desc->txd.callback_result = NULL; + + plxdev->tail++; + } + + spin_unlock_bh(&plxdev->ring_lock); +} + +static void __plx_dma_stop(struct plx_dma_dev *plxdev) +{ + unsigned long timeout = jiffies + msecs_to_jiffies(1000); + u32 val; + + val = readl(plxdev->bar + PLX_REG_CTRL); + if (!(val & ~PLX_REG_CTRL_GRACEFUL_PAUSE)) + return; + + writel(PLX_REG_CTRL_RESET_VAL | PLX_REG_CTRL_GRACEFUL_PAUSE, + plxdev->bar + PLX_REG_CTRL); + + while (!time_after(jiffies, timeout)) { + val = readl(plxdev->bar + PLX_REG_CTRL); + if (val & PLX_REG_CTRL_GRACEFUL_PAUSE_DONE) + break; + + cpu_relax(); + } + + if (!(val & PLX_REG_CTRL_GRACEFUL_PAUSE_DONE)) + dev_err(plxdev->dma_dev.dev, + "Timeout waiting for graceful pause!\n"); + + writel(PLX_REG_CTRL_RESET_VAL | PLX_REG_CTRL_GRACEFUL_PAUSE, + plxdev->bar + PLX_REG_CTRL); + + writel(0, plxdev->bar + PLX_REG_DESC_RING_COUNT); + writel(0, plxdev->bar + PLX_REG_DESC_RING_ADDR); + writel(0, plxdev->bar + PLX_REG_DESC_RING_ADDR_HI); + writel(0, plxdev->bar + PLX_REG_DESC_RING_NEXT_ADDR); +} + +static void plx_dma_stop(struct plx_dma_dev *plxdev) +{ + rcu_read_lock(); + if (!rcu_dereference(plxdev->pdev)) { + rcu_read_unlock(); + return; + } + + __plx_dma_stop(plxdev); + + rcu_read_unlock(); +} + +static void plx_dma_desc_task(struct tasklet_struct *t) +{ + struct plx_dma_dev *plxdev = from_tasklet(plxdev, t, desc_task); + + plx_dma_process_desc(plxdev); +} + +static struct dma_async_tx_descriptor *plx_dma_prep_memcpy(struct dma_chan *c, + dma_addr_t dma_dst, dma_addr_t dma_src, size_t len, + unsigned long flags) + __acquires(plxdev->ring_lock) +{ + struct plx_dma_dev *plxdev = chan_to_plx_dma_dev(c); + struct plx_dma_desc *plxdesc; + + spin_lock_bh(&plxdev->ring_lock); + if (!plxdev->ring_active) + goto err_unlock; + + if (!CIRC_SPACE(plxdev->head, plxdev->tail, PLX_DMA_RING_COUNT)) + goto err_unlock; + + if (len > PLX_DESC_SIZE_MASK) + goto err_unlock; + + plxdesc = plx_dma_get_desc(plxdev, plxdev->head); + plxdev->head++; + + plxdesc->hw->dst_addr_lo = cpu_to_le32(lower_32_bits(dma_dst)); + plxdesc->hw->dst_addr_hi = cpu_to_le16(upper_32_bits(dma_dst)); + plxdesc->hw->src_addr_lo = cpu_to_le32(lower_32_bits(dma_src)); + plxdesc->hw->src_addr_hi = cpu_to_le16(upper_32_bits(dma_src)); + + plxdesc->orig_size = len; + + if (flags & DMA_PREP_INTERRUPT) + len |= PLX_DESC_FLAG_INT_WHEN_DONE; + + plxdesc->hw->flags_and_size = cpu_to_le32(len); + plxdesc->txd.flags = flags; + + /* return with the lock held, it will be released in tx_submit */ + + return &plxdesc->txd; + +err_unlock: + /* + * Keep sparse happy by restoring an even lock count on + * this lock. + */ + __acquire(plxdev->ring_lock); + + spin_unlock_bh(&plxdev->ring_lock); + return NULL; +} + +static dma_cookie_t plx_dma_tx_submit(struct dma_async_tx_descriptor *desc) + __releases(plxdev->ring_lock) +{ + struct plx_dma_dev *plxdev = chan_to_plx_dma_dev(desc->chan); + struct plx_dma_desc *plxdesc = to_plx_desc(desc); + dma_cookie_t cookie; + + cookie = dma_cookie_assign(desc); + + /* + * Ensure the descriptor updates are visible to the dma device + * before setting the valid bit. + */ + wmb(); + + plxdesc->hw->flags_and_size |= cpu_to_le32(PLX_DESC_FLAG_VALID); + + spin_unlock_bh(&plxdev->ring_lock); + + return cookie; +} + +static enum dma_status plx_dma_tx_status(struct dma_chan *chan, + dma_cookie_t cookie, struct dma_tx_state *txstate) +{ + struct plx_dma_dev *plxdev = chan_to_plx_dma_dev(chan); + enum dma_status ret; + + ret = dma_cookie_status(chan, cookie, txstate); + if (ret == DMA_COMPLETE) + return ret; + + plx_dma_process_desc(plxdev); + + return dma_cookie_status(chan, cookie, txstate); +} + +static void plx_dma_issue_pending(struct dma_chan *chan) +{ + struct plx_dma_dev *plxdev = chan_to_plx_dma_dev(chan); + + rcu_read_lock(); + if (!rcu_dereference(plxdev->pdev)) { + rcu_read_unlock(); + return; + } + + /* + * Ensure the valid bits are visible before starting the + * DMA engine. + */ + wmb(); + + writew(PLX_REG_CTRL_START_VAL, plxdev->bar + PLX_REG_CTRL); + + rcu_read_unlock(); +} + +static irqreturn_t plx_dma_isr(int irq, void *devid) +{ + struct plx_dma_dev *plxdev = devid; + u32 status; + + status = readw(plxdev->bar + PLX_REG_INTR_STATUS); + + if (!status) + return IRQ_NONE; + + if (status & PLX_REG_INTR_STATUS_DESC_DONE && plxdev->ring_active) + tasklet_schedule(&plxdev->desc_task); + + writew(status, plxdev->bar + PLX_REG_INTR_STATUS); + + return IRQ_HANDLED; +} + +static int plx_dma_alloc_desc(struct plx_dma_dev *plxdev) +{ + struct plx_dma_desc *desc; + int i; + + plxdev->desc_ring = kcalloc(PLX_DMA_RING_COUNT, + sizeof(*plxdev->desc_ring), GFP_KERNEL); + if (!plxdev->desc_ring) + return -ENOMEM; + + for (i = 0; i < PLX_DMA_RING_COUNT; i++) { + desc = kzalloc(sizeof(*desc), GFP_KERNEL); + if (!desc) + goto free_and_exit; + + dma_async_tx_descriptor_init(&desc->txd, &plxdev->dma_chan); + desc->txd.tx_submit = plx_dma_tx_submit; + desc->hw = &plxdev->hw_ring[i]; + + plxdev->desc_ring[i] = desc; + } + + return 0; + +free_and_exit: + for (i = 0; i < PLX_DMA_RING_COUNT; i++) + kfree(plxdev->desc_ring[i]); + kfree(plxdev->desc_ring); + return -ENOMEM; +} + +static int plx_dma_alloc_chan_resources(struct dma_chan *chan) +{ + struct plx_dma_dev *plxdev = chan_to_plx_dma_dev(chan); + size_t ring_sz = PLX_DMA_RING_COUNT * sizeof(*plxdev->hw_ring); + int rc; + + plxdev->head = plxdev->tail = 0; + plxdev->hw_ring = dma_alloc_coherent(plxdev->dma_dev.dev, ring_sz, + &plxdev->hw_ring_dma, GFP_KERNEL); + if (!plxdev->hw_ring) + return -ENOMEM; + + rc = plx_dma_alloc_desc(plxdev); + if (rc) + goto out_free_hw_ring; + + rcu_read_lock(); + if (!rcu_dereference(plxdev->pdev)) { + rcu_read_unlock(); + rc = -ENODEV; + goto out_free_hw_ring; + } + + writel(PLX_REG_CTRL_RESET_VAL, plxdev->bar + PLX_REG_CTRL); + writel(lower_32_bits(plxdev->hw_ring_dma), + plxdev->bar + PLX_REG_DESC_RING_ADDR); + writel(upper_32_bits(plxdev->hw_ring_dma), + plxdev->bar + PLX_REG_DESC_RING_ADDR_HI); + writel(lower_32_bits(plxdev->hw_ring_dma), + plxdev->bar + PLX_REG_DESC_RING_NEXT_ADDR); + writel(PLX_DMA_RING_COUNT, plxdev->bar + PLX_REG_DESC_RING_COUNT); + writel(PLX_REG_PREF_LIMIT_PREF_FOUR, plxdev->bar + PLX_REG_PREF_LIMIT); + + plxdev->ring_active = true; + + rcu_read_unlock(); + + return PLX_DMA_RING_COUNT; + +out_free_hw_ring: + dma_free_coherent(plxdev->dma_dev.dev, ring_sz, plxdev->hw_ring, + plxdev->hw_ring_dma); + return rc; +} + +static void plx_dma_free_chan_resources(struct dma_chan *chan) +{ + struct plx_dma_dev *plxdev = chan_to_plx_dma_dev(chan); + size_t ring_sz = PLX_DMA_RING_COUNT * sizeof(*plxdev->hw_ring); + struct pci_dev *pdev; + int irq = -1; + int i; + + spin_lock_bh(&plxdev->ring_lock); + plxdev->ring_active = false; + spin_unlock_bh(&plxdev->ring_lock); + + plx_dma_stop(plxdev); + + rcu_read_lock(); + pdev = rcu_dereference(plxdev->pdev); + if (pdev) + irq = pci_irq_vector(pdev, 0); + rcu_read_unlock(); + + if (irq > 0) + synchronize_irq(irq); + + tasklet_kill(&plxdev->desc_task); + + plx_dma_abort_desc(plxdev); + + for (i = 0; i < PLX_DMA_RING_COUNT; i++) + kfree(plxdev->desc_ring[i]); + + kfree(plxdev->desc_ring); + dma_free_coherent(plxdev->dma_dev.dev, ring_sz, plxdev->hw_ring, + plxdev->hw_ring_dma); + +} + +static void plx_dma_release(struct dma_device *dma_dev) +{ + struct plx_dma_dev *plxdev = + container_of(dma_dev, struct plx_dma_dev, dma_dev); + + put_device(dma_dev->dev); + kfree(plxdev); +} + +static int plx_dma_create(struct pci_dev *pdev) +{ + struct plx_dma_dev *plxdev; + struct dma_device *dma; + struct dma_chan *chan; + int rc; + + plxdev = kzalloc(sizeof(*plxdev), GFP_KERNEL); + if (!plxdev) + return -ENOMEM; + + rc = request_irq(pci_irq_vector(pdev, 0), plx_dma_isr, 0, + KBUILD_MODNAME, plxdev); + if (rc) + goto free_plx; + + spin_lock_init(&plxdev->ring_lock); + tasklet_setup(&plxdev->desc_task, plx_dma_desc_task); + + RCU_INIT_POINTER(plxdev->pdev, pdev); + plxdev->bar = pcim_iomap_table(pdev)[0]; + + dma = &plxdev->dma_dev; + dma->chancnt = 1; + INIT_LIST_HEAD(&dma->channels); + dma_cap_set(DMA_MEMCPY, dma->cap_mask); + dma->copy_align = DMAENGINE_ALIGN_1_BYTE; + dma->dev = get_device(&pdev->dev); + + dma->device_alloc_chan_resources = plx_dma_alloc_chan_resources; + dma->device_free_chan_resources = plx_dma_free_chan_resources; + dma->device_prep_dma_memcpy = plx_dma_prep_memcpy; + dma->device_issue_pending = plx_dma_issue_pending; + dma->device_tx_status = plx_dma_tx_status; + dma->device_release = plx_dma_release; + + chan = &plxdev->dma_chan; + chan->device = dma; + dma_cookie_init(chan); + list_add_tail(&chan->device_node, &dma->channels); + + rc = dma_async_device_register(dma); + if (rc) { + pci_err(pdev, "Failed to register dma device: %d\n", rc); + goto put_device; + } + + pci_set_drvdata(pdev, plxdev); + + return 0; + +put_device: + put_device(&pdev->dev); + free_irq(pci_irq_vector(pdev, 0), plxdev); +free_plx: + kfree(plxdev); + + return rc; +} + +static int plx_dma_probe(struct pci_dev *pdev, + const struct pci_device_id *id) +{ + int rc; + + rc = pcim_enable_device(pdev); + if (rc) + return rc; + + rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(48)); + if (rc) + rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32)); + if (rc) + return rc; + + rc = pcim_iomap_regions(pdev, 1, KBUILD_MODNAME); + if (rc) + return rc; + + rc = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES); + if (rc <= 0) + return rc; + + pci_set_master(pdev); + + rc = plx_dma_create(pdev); + if (rc) + goto err_free_irq_vectors; + + pci_info(pdev, "PLX DMA Channel Registered\n"); + + return 0; + +err_free_irq_vectors: + pci_free_irq_vectors(pdev); + return rc; +} + +static void plx_dma_remove(struct pci_dev *pdev) +{ + struct plx_dma_dev *plxdev = pci_get_drvdata(pdev); + + free_irq(pci_irq_vector(pdev, 0), plxdev); + + rcu_assign_pointer(plxdev->pdev, NULL); + synchronize_rcu(); + + spin_lock_bh(&plxdev->ring_lock); + plxdev->ring_active = false; + spin_unlock_bh(&plxdev->ring_lock); + + __plx_dma_stop(plxdev); + plx_dma_abort_desc(plxdev); + + plxdev->bar = NULL; + dma_async_device_unregister(&plxdev->dma_dev); + + pci_free_irq_vectors(pdev); +} + +static const struct pci_device_id plx_dma_pci_tbl[] = { + { + .vendor = PCI_VENDOR_ID_PLX, + .device = 0x87D0, + .subvendor = PCI_ANY_ID, + .subdevice = PCI_ANY_ID, + .class = PCI_CLASS_SYSTEM_OTHER << 8, + .class_mask = 0xFFFFFFFF, + }, + {0} +}; +MODULE_DEVICE_TABLE(pci, plx_dma_pci_tbl); + +static struct pci_driver plx_dma_pci_driver = { + .name = KBUILD_MODNAME, + .id_table = plx_dma_pci_tbl, + .probe = plx_dma_probe, + .remove = plx_dma_remove, +}; +module_pci_driver(plx_dma_pci_driver); |