[PATCH v2] dmaengine: idxd: check device state before issue command

[Dave Jiang <dave.jiang@intel.com>]

Add device state check before executing command. Without the check the
command can be issued while device is in halt state and causes the driver to
block while waiting for the completion of the command.

Reported-by: Sanjay Kumar <sanjay.k.kumar@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Tested-by: Sanjay Kumar <sanjay.k.kumar@intel.com>
Fixes: 0d5c10b4c84d ("dmaengine: idxd: add work queue drain support")
---

v2:
- simplify idxd_device_is_halted() return code (Vinod)

 drivers/dma/idxd/device.c |   23 ++++++++++++++++++++++-
 drivers/dma/idxd/idxd.h   |    2 +-
 drivers/dma/idxd/init.c   |    5 ++++-
 3 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index 95f94a3ed6be..84a6ea60ecf0 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -398,17 +398,31 @@ static inline bool idxd_is_enabled(struct idxd_device *idxd)
 	return false;
 }
 
+static inline bool idxd_device_is_halted(struct idxd_device *idxd)
+{
+	union gensts_reg gensts;
+
+	gensts.bits = ioread32(idxd->reg_base + IDXD_GENSTATS_OFFSET);
+
+	return (gensts.state == IDXD_DEVICE_STATE_HALT);
+}
+
 /*
  * This is function is only used for reset during probe and will
  * poll for completion. Once the device is setup with interrupts,
  * all commands will be done via interrupt completion.
  */
-void idxd_device_init_reset(struct idxd_device *idxd)
+int idxd_device_init_reset(struct idxd_device *idxd)
 {
 	struct device *dev = &idxd->pdev->dev;
 	union idxd_command_reg cmd;
 	unsigned long flags;
 
+	if (idxd_device_is_halted(idxd)) {
+		dev_warn(&idxd->pdev->dev, "Device is HALTED!\n");
+		return -ENXIO;
+	}
+
 	memset(&cmd, 0, sizeof(cmd));
 	cmd.cmd = IDXD_CMD_RESET_DEVICE;
 	dev_dbg(dev, "%s: sending reset for init.\n", __func__);
@@ -419,6 +433,7 @@ void idxd_device_init_reset(struct idxd_device *idxd)
 	       IDXD_CMDSTS_ACTIVE)
 		cpu_relax();
 	spin_unlock_irqrestore(&idxd->dev_lock, flags);
+	return 0;
 }
 
 static void idxd_cmd_exec(struct idxd_device *idxd, int cmd_code, u32 operand,
@@ -428,6 +443,12 @@ static void idxd_cmd_exec(struct idxd_device *idxd, int cmd_code, u32 operand,
 	DECLARE_COMPLETION_ONSTACK(done);
 	unsigned long flags;
 
+	if (idxd_device_is_halted(idxd)) {
+		dev_warn(&idxd->pdev->dev, "Device is HALTED!\n");
+		*status = IDXD_CMDSTS_HW_ERR;
+		return;
+	}
+
 	memset(&cmd, 0, sizeof(cmd));
 	cmd.cmd = cmd_code;
 	cmd.operand = operand;
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index 5a50e91c71bf..81a0e65fd316 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -326,7 +326,7 @@ void idxd_mask_msix_vector(struct idxd_device *idxd, int vec_id);
 void idxd_unmask_msix_vector(struct idxd_device *idxd, int vec_id);
 
 /* device control */
-void idxd_device_init_reset(struct idxd_device *idxd);
+int idxd_device_init_reset(struct idxd_device *idxd);
 int idxd_device_enable(struct idxd_device *idxd);
 int idxd_device_disable(struct idxd_device *idxd);
 void idxd_device_reset(struct idxd_device *idxd);
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index 2c051e07c34c..fa04acd5582a 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -335,7 +335,10 @@ static int idxd_probe(struct idxd_device *idxd)
 	int rc;
 
 	dev_dbg(dev, "%s entered and resetting device\n", __func__);
-	idxd_device_init_reset(idxd);
+	rc = idxd_device_init_reset(idxd);
+	if (rc < 0)
+		return rc;
+
 	dev_dbg(dev, "IDXD reset complete\n");
 
 	if (IS_ENABLED(CONFIG_INTEL_IDXD_SVM)) {