habanalabs: add event queue and interrupts

This patch adds support for receiving events from Goya's control CPU and
for receiving MSI-X interrupts from Goya's DMA engines and CPU.

Goya's PCI controller supports up to 8 MSI-X interrupts, which only 6 of
them are currently used. The first 5 interrupts are dedicated for Goya's
DMA engine queues. The 6th interrupt is dedicated for Goya's control CPU.

The DMA queue will signal its MSI-X entry upon each completion of a command
buffer that was placed on its primary queue. The driver will then mark that
CB as completed and free the related resources. It will also update the
command submission object which that CB belongs to.

There is a dedicated event queue (EQ) between the driver and Goya's control
CPU. The EQ is located on the Host memory. The control CPU writes a new
entry to the EQ for various reasons, such as ECC error, MMU page fault, Hot
temperature. After writing the new entry to the EQ, the control CPU will
trigger its dedicated MSI-X entry to signal the driver that there is a new
entry in the EQ. The driver will then read the entry and act accordingly.

Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 146 insertions, 1 deletions

diff --git a/drivers/misc/habanalabs/irq.c b/drivers/misc/habanalabs/irq.c
index 6b7d35f6af08..c12116042d8b 100644
--- a/drivers/misc/habanalabs/irq.c
+++ b/drivers/misc/habanalabs/irq.c
@@ -7,7 +7,20 @@
 
 #include "habanalabs.h"
 
-#include <linux/irqreturn.h>
+#include <linux/slab.h>
+
+/**
+ * This structure is used to schedule work of EQ entry and armcp_reset event
+ *
+ * @eq_work          - workqueue object to run when EQ entry is received
+ * @hdev             - pointer to device structure
+ * @eq_entry         - copy of the EQ entry
+ */
+struct hl_eqe_work {
+	struct work_struct	eq_work;
+	struct hl_device	*hdev;
+	struct hl_eq_entry	eq_entry;
+};
 
 /*
  * hl_cq_inc_ptr - increment ci or pi of cq
@@ -26,6 +39,33 @@ inline u32 hl_cq_inc_ptr(u32 ptr)
 }
 
 /*
+ * hl_eq_inc_ptr - increment ci of eq
+ *
+ * @ptr: the current ci value of the event queue
+ *
+ * Increment ptr by 1. If it reaches the number of event queue
+ * entries, set it to 0
+ */
+inline u32 hl_eq_inc_ptr(u32 ptr)
+{
+	ptr++;
+	if (unlikely(ptr == HL_EQ_LENGTH))
+		ptr = 0;
+	return ptr;
+}
+
+static void irq_handle_eqe(struct work_struct *work)
+{
+	struct hl_eqe_work *eqe_work = container_of(work, struct hl_eqe_work,
+							eq_work);
+	struct hl_device *hdev = eqe_work->hdev;
+
+	hdev->asic_funcs->handle_eqe(hdev, &eqe_work->eq_entry);
+
+	kfree(eqe_work);
+}
+
+/*
  * hl_irq_handler_cq - irq handler for completion queue
  *
  * @irq: irq number
@@ -103,6 +143,68 @@ irqreturn_t hl_irq_handler_cq(int irq, void *arg)
 }
 
 /*
+ * hl_irq_handler_eq - irq handler for event queue
+ *
+ * @irq: irq number
+ * @arg: pointer to event queue structure
+ *
+ */
+irqreturn_t hl_irq_handler_eq(int irq, void *arg)
+{
+	struct hl_eq *eq = arg;
+	struct hl_device *hdev = eq->hdev;
+	struct hl_eq_entry *eq_entry;
+	struct hl_eq_entry *eq_base;
+	struct hl_eqe_work *handle_eqe_work;
+
+	eq_base = (struct hl_eq_entry *) (uintptr_t) eq->kernel_address;
+
+	while (1) {
+		bool entry_ready =
+				((eq_base[eq->ci].hdr.ctl & EQ_CTL_READY_MASK)
+						>> EQ_CTL_READY_SHIFT);
+
+		if (!entry_ready)
+			break;
+
+		eq_entry = &eq_base[eq->ci];
+
+		/*
+		 * Make sure we read EQ entry contents after we've
+		 * checked the ownership bit.
+		 */
+		dma_rmb();
+
+		if (hdev->disabled) {
+			dev_warn(hdev->dev,
+				"Device disabled but received IRQ %d for EQ\n",
+					irq);
+			goto skip_irq;
+		}
+
+		handle_eqe_work = kmalloc(sizeof(*handle_eqe_work), GFP_ATOMIC);
+		if (handle_eqe_work) {
+			INIT_WORK(&handle_eqe_work->eq_work, irq_handle_eqe);
+			handle_eqe_work->hdev = hdev;
+
+			memcpy(&handle_eqe_work->eq_entry, eq_entry,
+					sizeof(*eq_entry));
+
+			queue_work(hdev->eq_wq, &handle_eqe_work->eq_work);
+		}
+skip_irq:
+		/* Clear EQ entry ready bit */
+		eq_entry->hdr.ctl &= ~EQ_CTL_READY_MASK;
+
+		eq->ci = hl_eq_inc_ptr(eq->ci);
+
+		hdev->asic_funcs->update_eq_ci(hdev, eq->ci);
+	}
+
+	return IRQ_HANDLED;
+}
+
+/*
  * hl_cq_init - main initialization function for an cq object
  *
  * @hdev: pointer to device structure
@@ -147,3 +249,46 @@ void hl_cq_fini(struct hl_device *hdev, struct hl_cq *q)
 	hdev->asic_funcs->dma_free_coherent(hdev, HL_CQ_SIZE_IN_BYTES,
 			(void *) (uintptr_t) q->kernel_address, q->bus_address);
 }
+
+/*
+ * hl_eq_init - main initialization function for an event queue object
+ *
+ * @hdev: pointer to device structure
+ * @q: pointer to eq structure
+ *
+ * Allocate dma-able memory for the event queue and initialize fields
+ * Returns 0 on success
+ */
+int hl_eq_init(struct hl_device *hdev, struct hl_eq *q)
+{
+	void *p;
+
+	BUILD_BUG_ON(HL_EQ_SIZE_IN_BYTES > HL_PAGE_SIZE);
+
+	p = hdev->asic_funcs->dma_alloc_coherent(hdev, HL_EQ_SIZE_IN_BYTES,
+				&q->bus_address, GFP_KERNEL | __GFP_ZERO);
+	if (!p)
+		return -ENOMEM;
+
+	q->hdev = hdev;
+	q->kernel_address = (u64) (uintptr_t) p;
+	q->ci = 0;
+
+	return 0;
+}
+
+/*
+ * hl_eq_fini - destroy event queue
+ *
+ * @hdev: pointer to device structure
+ * @q: pointer to eq structure
+ *
+ * Free the event queue memory
+ */
+void hl_eq_fini(struct hl_device *hdev, struct hl_eq *q)
+{
+	flush_workqueue(hdev->eq_wq);
+
+	hdev->asic_funcs->dma_free_coherent(hdev, HL_EQ_SIZE_IN_BYTES,
+			(void *) (uintptr_t) q->kernel_address, q->bus_address);
+}