dmaengine: idxd: Init and probe for Intel data accelerators

The idxd driver introduces the Intel Data Stream Accelerator [1] that will
be available on future Intel Xeon CPUs. One of the kernel access
point for the driver is through the dmaengine subsystem. It will initially
provide the DMA copy service to the kernel.

Some of the main functionality introduced with this accelerator
are: shared virtual memory (SVM) support, and descriptor submission using
Intel CPU instructions movdir64b and enqcmds. There will be additional
accelerator devices that share the same driver with variations to
capabilities.

This commit introduces the probe and initialization component of the
driver.

[1]: https://software.intel.com/en-us/download/intel-data-streaming-accelerator-preliminary-architecture-specification

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/157965023991.73301.6186843973135311580.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 156 insertions, 0 deletions

diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
new file mode 100644
index 000000000000..de4b80973c2f
--- /dev/null
+++ b/drivers/dma/idxd/irq.c
@@ -0,0 +1,156 @@
+// 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 <uapi/linux/idxd.h>
+#include "idxd.h"
+#include "registers.h"
+
+void idxd_device_wqs_clear_state(struct idxd_device *idxd)
+{
+	int i;
+
+	lockdep_assert_held(&idxd->dev_lock);
+	for (i = 0; i < idxd->max_wqs; i++) {
+		struct idxd_wq *wq = &idxd->wqs[i];
+
+		wq->state = IDXD_WQ_DISABLED;
+	}
+}
+
+static int idxd_restart(struct idxd_device *idxd)
+{
+	int i, rc;
+
+	lockdep_assert_held(&idxd->dev_lock);
+
+	rc = __idxd_device_reset(idxd);
+	if (rc < 0)
+		goto out;
+
+	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(&idxd->pdev->dev,
+					 "Unable to re-enable wq %s\n",
+					 dev_name(&wq->conf_dev));
+			}
+		}
+	}
+
+	return 0;
+
+ out:
+	idxd_device_wqs_clear_state(idxd);
+	idxd->state = IDXD_DEV_HALTED;
+	return rc;
+}
+
+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;
+}
+
+irqreturn_t idxd_misc_thread(int vec, void *data)
+{
+	struct idxd_irq_entry *irq_entry = data;
+	struct idxd_device *idxd = irq_entry->idxd;
+	struct device *dev = &idxd->pdev->dev;
+	union gensts_reg gensts;
+	u32 cause, val = 0;
+	int i, rc;
+	bool err = false;
+
+	cause = ioread32(idxd->reg_base + IDXD_INTCAUSE_OFFSET);
+
+	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_SWERR_ACK, idxd->reg_base + IDXD_SWERR_OFFSET);
+		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) {
+		/* Driver does use command interrupts */
+		val |= IDXD_INTC_CMD;
+	}
+
+	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);
+
+	iowrite32(cause, idxd->reg_base + IDXD_INTCAUSE_OFFSET);
+	if (!err)
+		return IRQ_HANDLED;
+
+	gensts.bits = ioread32(idxd->reg_base + IDXD_GENSTATS_OFFSET);
+	if (gensts.state == IDXD_DEVICE_STATE_HALT) {
+		spin_lock_bh(&idxd->dev_lock);
+		if (gensts.reset_type == IDXD_DEVICE_RESET_SOFTWARE) {
+			rc = idxd_restart(idxd);
+			if (rc < 0)
+				dev_err(&idxd->pdev->dev,
+					"idxd restart failed, device halt.");
+		} else {
+			idxd_device_wqs_clear_state(idxd);
+			idxd->state = IDXD_DEV_HALTED;
+			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);
+	}
+
+	idxd_unmask_msix_vector(idxd, irq_entry->id);
+	return IRQ_HANDLED;
+}
+
+irqreturn_t idxd_wq_thread(int irq, void *data)
+{
+	struct idxd_irq_entry *irq_entry = data;
+
+	idxd_unmask_msix_vector(irq_entry->idxd, irq_entry->id);
+
+	return IRQ_HANDLED;
+}