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 *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_bh(&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_bh(&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(unsigned long data)
+{
+ struct plx_dma_dev *plxdev = (void *)data;
+
+ plx_dma_process_desc(plxdev);
+}
+
+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->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 =
if (!plxdev)
return -ENOMEM;
+ rc = request_irq(pci_irq_vector(pdev, 0), plx_dma_isr, 0,
+ KBUILD_MODNAME, plxdev);
+ if (rc) {
+ kfree(plxdev);
+ return rc;
+ }
+
+ spin_lock_init(&plxdev->ring_lock);
+ tasklet_init(&plxdev->desc_task, plx_dma_desc_task,
+ (unsigned long)plxdev);
+
+ RCU_INIT_POINTER(plxdev->pdev, pdev);
plxdev->bar = pcim_iomap_table(pdev)[0];
dma = &plxdev->dma_dev;
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_release = plx_dma_release;
chan = &plxdev->dma_chan;
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);
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