dmaengine: idxd: add interrupt handle request and release support

DSA spec states that when Request Interrupt Handle and Release Interrupt
Handle command bits are set in the CMDCAP register, these device commands
must be supported by the driver.

The interrupt handle is programmed in a descriptor. When Request Interrupt
Handle is not supported, the interrupt handle is the index of the desired
entry in the MSI-X table. When the command is supported, driver must use
the command to obtain a handle to be programmed in the submitted
descriptor.

A requested handle may be revoked. After the handle is revoked, any use of
the handle will result in Invalid Interrupt Handle error.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/161894439422.3202472.17579543737810265471.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 71 insertions, 0 deletions

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index 3ddb1c731080..54d5afec81cf 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -598,6 +598,77 @@ void idxd_device_drain_pasid(struct idxd_device *idxd, int pasid)
 	dev_dbg(dev, "pasid %d drained\n", pasid);
 }
 
+int idxd_device_request_int_handle(struct idxd_device *idxd, int idx, int *handle,
+				   enum idxd_interrupt_type irq_type)
+{
+	struct device *dev = &idxd->pdev->dev;
+	u32 operand, status;
+
+	if (!(idxd->hw.cmd_cap & BIT(IDXD_CMD_REQUEST_INT_HANDLE)))
+		return -EOPNOTSUPP;
+
+	dev_dbg(dev, "get int handle, idx %d\n", idx);
+
+	operand = idx & GENMASK(15, 0);
+	if (irq_type == IDXD_IRQ_IMS)
+		operand |= CMD_INT_HANDLE_IMS;
+
+	dev_dbg(dev, "cmd: %u operand: %#x\n", IDXD_CMD_REQUEST_INT_HANDLE, operand);
+
+	idxd_cmd_exec(idxd, IDXD_CMD_REQUEST_INT_HANDLE, operand, &status);
+
+	if ((status & IDXD_CMDSTS_ERR_MASK) != IDXD_CMDSTS_SUCCESS) {
+		dev_dbg(dev, "request int handle failed: %#x\n", status);
+		return -ENXIO;
+	}
+
+	*handle = (status >> IDXD_CMDSTS_RES_SHIFT) & GENMASK(15, 0);
+
+	dev_dbg(dev, "int handle acquired: %u\n", *handle);
+	return 0;
+}
+
+int idxd_device_release_int_handle(struct idxd_device *idxd, int handle,
+				   enum idxd_interrupt_type irq_type)
+{
+	struct device *dev = &idxd->pdev->dev;
+	u32 operand, status;
+	union idxd_command_reg cmd;
+	unsigned long flags;
+
+	if (!(idxd->hw.cmd_cap & BIT(IDXD_CMD_RELEASE_INT_HANDLE)))
+		return -EOPNOTSUPP;
+
+	dev_dbg(dev, "release int handle, handle %d\n", handle);
+
+	memset(&cmd, 0, sizeof(cmd));
+	operand = handle & GENMASK(15, 0);
+
+	if (irq_type == IDXD_IRQ_IMS)
+		operand |= CMD_INT_HANDLE_IMS;
+
+	cmd.cmd = IDXD_CMD_RELEASE_INT_HANDLE;
+	cmd.operand = operand;
+
+	dev_dbg(dev, "cmd: %u operand: %#x\n", IDXD_CMD_RELEASE_INT_HANDLE, operand);
+
+	spin_lock_irqsave(&idxd->dev_lock, flags);
+	iowrite32(cmd.bits, idxd->reg_base + IDXD_CMD_OFFSET);
+
+	while (ioread32(idxd->reg_base + IDXD_CMDSTS_OFFSET) & IDXD_CMDSTS_ACTIVE)
+		cpu_relax();
+	status = ioread32(idxd->reg_base + IDXD_CMDSTS_OFFSET);
+	spin_unlock_irqrestore(&idxd->dev_lock, flags);
+
+	if ((status & IDXD_CMDSTS_ERR_MASK) != IDXD_CMDSTS_SUCCESS) {
+		dev_dbg(dev, "release int handle failed: %#x\n", status);
+		return -ENXIO;
+	}
+
+	dev_dbg(dev, "int handle released.\n");
+	return 0;
+}
+
 /* Device configuration bits */
 void idxd_msix_perm_setup(struct idxd_device *idxd)
 {