1 files changed, 277 insertions, 0 deletions
diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
new file mode 100644
index 000000000..fc9579180
--- /dev/null
+++ b/drivers/dma/idxd/irq.c
@@ -0,0 +1,277 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2019 Intel Corporation. All rights rsvd. */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/dmaengine.h>
+#include <uapi/linux/idxd.h>
+#include "../dmaengine.h"
+#include "idxd.h"
+#include "registers.h"
+
+static void idxd_device_reinit(struct work_struct *work)
+{
+	struct idxd_device *idxd = container_of(work, struct idxd_device, work);
+	struct device *dev = &idxd->pdev->dev;
+	int rc, i;
+
+	idxd_device_reset(idxd);
+	rc = idxd_device_config(idxd);
+	if (rc < 0)
+		goto out;
+
+	rc = idxd_device_enable(idxd);
+	if (rc < 0)
+		goto out;
+
+	for (i = 0; i < idxd->max_wqs; i++) {
+		struct idxd_wq *wq = &idxd->wqs[i];
+
+		if (wq->state == IDXD_WQ_ENABLED) {
+			rc = idxd_wq_enable(wq);
+			if (rc < 0) {
+				dev_warn(dev, "Unable to re-enable wq %s\n",
+					 dev_name(&wq->conf_dev));
+			}
+		}
+	}
+
+	return;
+
+ out:
+	idxd_device_wqs_clear_state(idxd);
+}
+
+irqreturn_t idxd_irq_handler(int vec, void *data)
+{
+	struct idxd_irq_entry *irq_entry = data;
+	struct idxd_device *idxd = irq_entry->idxd;
+
+	idxd_mask_msix_vector(idxd, irq_entry->id);
+	return IRQ_WAKE_THREAD;
+}
+
+static int process_misc_interrupts(struct idxd_device *idxd, u32 cause)
+{
+	struct device *dev = &idxd->pdev->dev;
+	union gensts_reg gensts;
+	u32 val = 0;
+	int i;
+	bool err = false;
+
+	if (cause & IDXD_INTC_ERR) {
+		spin_lock_bh(&idxd->dev_lock);
+		for (i = 0; i < 4; i++)
+			idxd->sw_err.bits[i] = ioread64(idxd->reg_base +
+					IDXD_SWERR_OFFSET + i * sizeof(u64));
+
+		iowrite64(idxd->sw_err.bits[0] & IDXD_SWERR_ACK,
+			  idxd->reg_base + IDXD_SWERR_OFFSET);
+
+		if (idxd->sw_err.valid && idxd->sw_err.wq_idx_valid) {
+			int id = idxd->sw_err.wq_idx;
+			struct idxd_wq *wq = &idxd->wqs[id];
+
+			if (wq->type == IDXD_WQT_USER)
+				wake_up_interruptible(&wq->err_queue);
+		} else {
+			int i;
+
+			for (i = 0; i < idxd->max_wqs; i++) {
+				struct idxd_wq *wq = &idxd->wqs[i];
+
+				if (wq->type == IDXD_WQT_USER)
+					wake_up_interruptible(&wq->err_queue);
+			}
+		}
+
+		spin_unlock_bh(&idxd->dev_lock);
+		val |= IDXD_INTC_ERR;
+
+		for (i = 0; i < 4; i++)
+			dev_warn(dev, "err[%d]: %#16.16llx\n",
+				 i, idxd->sw_err.bits[i]);
+		err = true;
+	}
+
+	if (cause & IDXD_INTC_CMD) {
+		val |= IDXD_INTC_CMD;
+		complete(idxd->cmd_done);
+	}
+
+	if (cause & IDXD_INTC_OCCUPY) {
+		/* Driver does not utilize occupancy interrupt */
+		val |= IDXD_INTC_OCCUPY;
+	}
+
+	if (cause & IDXD_INTC_PERFMON_OVFL) {
+		/*
+		 * Driver does not utilize perfmon counter overflow interrupt
+		 * yet.
+		 */
+		val |= IDXD_INTC_PERFMON_OVFL;
+	}
+
+	val ^= cause;
+	if (val)
+		dev_warn_once(dev, "Unexpected interrupt cause bits set: %#x\n",
+			      val);
+
+	if (!err)
+		return 0;
+
+	gensts.bits = ioread32(idxd->reg_base + IDXD_GENSTATS_OFFSET);
+	if (gensts.state == IDXD_DEVICE_STATE_HALT) {
+		idxd->state = IDXD_DEV_HALTED;
+		if (gensts.reset_type == IDXD_DEVICE_RESET_SOFTWARE) {
+			/*
+			 * If we need a software reset, we will throw the work
+			 * on a system workqueue in order to allow interrupts
+			 * for the device command completions.
+			 */
+			INIT_WORK(&idxd->work, idxd_device_reinit);
+			queue_work(idxd->wq, &idxd->work);
+		} else {
+			spin_lock_bh(&idxd->dev_lock);
+			idxd_device_wqs_clear_state(idxd);
+			dev_err(&idxd->pdev->dev,
+				"idxd halted, need %s.\n",
+				gensts.reset_type == IDXD_DEVICE_RESET_FLR ?
+				"FLR" : "system reset");
+			spin_unlock_bh(&idxd->dev_lock);
+			return -ENXIO;
+		}
+	}
+
+	return 0;
+}
+
+irqreturn_t idxd_misc_thread(int vec, void *data)
+{
+	struct idxd_irq_entry *irq_entry = data;
+	struct idxd_device *idxd = irq_entry->idxd;
+	int rc;
+	u32 cause;
+
+	cause = ioread32(idxd->reg_base + IDXD_INTCAUSE_OFFSET);
+	if (cause)
+		iowrite32(cause, idxd->reg_base + IDXD_INTCAUSE_OFFSET);
+
+	while (cause) {
+		rc = process_misc_interrupts(idxd, cause);
+		if (rc < 0)
+			break;
+		cause = ioread32(idxd->reg_base + IDXD_INTCAUSE_OFFSET);
+		if (cause)
+			iowrite32(cause, idxd->reg_base + IDXD_INTCAUSE_OFFSET);
+	}
+
+	idxd_unmask_msix_vector(idxd, irq_entry->id);
+	return IRQ_HANDLED;
+}
+
+static int irq_process_pending_llist(struct idxd_irq_entry *irq_entry,
+				     int *processed)
+{
+	struct idxd_desc *desc, *t;
+	struct llist_node *head;
+	int queued = 0;
+
+	*processed = 0;
+	head = llist_del_all(&irq_entry->pending_llist);
+	if (!head)
+		return 0;
+
+	llist_for_each_entry_safe(desc, t, head, llnode) {
+		if (desc->completion->status) {
+			idxd_dma_complete_txd(desc, IDXD_COMPLETE_NORMAL);
+			idxd_free_desc(desc->wq, desc);
+			(*processed)++;
+		} else {
+			list_add_tail(&desc->list, &irq_entry->work_list);
+			queued++;
+		}
+	}
+
+	return queued;
+}
+
+static int irq_process_work_list(struct idxd_irq_entry *irq_entry,
+				 int *processed)
+{
+	struct list_head *node, *next;
+	int queued = 0;
+
+	*processed = 0;
+	if (list_empty(&irq_entry->work_list))
+		return 0;
+
+	list_for_each_safe(node, next, &irq_entry->work_list) {
+		struct idxd_desc *desc =
+			container_of(node, struct idxd_desc, list);
+
+		if (desc->completion->status) {
+			list_del(&desc->list);
+			/* process and callback */
+			idxd_dma_complete_txd(desc, IDXD_COMPLETE_NORMAL);
+			idxd_free_desc(desc->wq, desc);
+			(*processed)++;
+		} else {
+			queued++;
+		}
+	}
+
+	return queued;
+}
+
+static int idxd_desc_process(struct idxd_irq_entry *irq_entry)
+{
+	int rc, processed, total = 0;
+
+	/*
+	 * There are two lists we are processing. The pending_llist is where
+	 * submmiter adds all the submitted descriptor after sending it to
+	 * the workqueue. It's a lockless singly linked list. The work_list
+	 * is the common linux double linked list. We are in a scenario of
+	 * multiple producers and a single consumer. The producers are all
+	 * the kernel submitters of descriptors, and the consumer is the
+	 * kernel irq handler thread for the msix vector when using threaded
+	 * irq. To work with the restrictions of llist to remain lockless,
+	 * we are doing the following steps:
+	 * 1. Iterate through the work_list and process any completed
+	 *    descriptor. Delete the completed entries during iteration.
+	 * 2. llist_del_all() from the pending list.
+	 * 3. Iterate through the llist that was deleted from the pending list
+	 *    and process the completed entries.
+	 * 4. If the entry is still waiting on hardware, list_add_tail() to
+	 *    the work_list.
+	 * 5. Repeat until no more descriptors.
+	 */
+	do {
+		rc = irq_process_work_list(irq_entry, &processed);
+		total += processed;
+		if (rc != 0)
+			continue;
+
+		rc = irq_process_pending_llist(irq_entry, &processed);
+		total += processed;
+	} while (rc != 0);
+
+	return total;
+}
+
+irqreturn_t idxd_wq_thread(int irq, void *data)
+{
+	struct idxd_irq_entry *irq_entry = data;
+	int processed;
+
+	processed = idxd_desc_process(irq_entry);
+	idxd_unmask_msix_vector(irq_entry->idxd, irq_entry->id);
+
+	if (processed == 0)
+		return IRQ_NONE;
+
+	return IRQ_HANDLED;
+}