[PATCH RFC 03/17] of: Use -ENODEV consistently in of_iommu_configure()

[Jason Gunthorpe]

Instead of returning 1 and trying to handle positive error codes just
stick to the convention of returning -ENODEV. Remove references to ops
from of_iommu_configure(), a NULL ops will already generate an error code.

There is no reason to check dev->bus, if err=0 at this point then the
called configure functions thought there was an iommu and we should try to
probe it. Remove it.

Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>
---
 drivers/iommu/of_iommu.c | 42 +++++++++++++---------------------------
 1 file changed, 13 insertions(+), 29 deletions(-)

diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index e2fa29c16dd758..4f77495a2543ea 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -17,7 +17,7 @@
 #include <linux/slab.h>
 #include <linux/fsl/mc.h>
 
-#define NO_IOMMU	1
+#define NO_IOMMU	-ENODEV
 
 static int of_iommu_xlate(struct device *dev,
 			  struct of_phandle_args *iommu_spec)
@@ -117,9 +117,8 @@ static int of_iommu_configure_device(struct device_node *master_np,
 int of_iommu_configure(struct device *dev, struct device_node *master_np,
 		       const u32 *id)
 {
-	const struct iommu_ops *ops = NULL;
 	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
-	int err = NO_IOMMU;
+	int err;
 
 	if (!master_np)
 		return -ENODEV;
@@ -150,34 +149,19 @@ int of_iommu_configure(struct device *dev, struct device_node *master_np,
 		err = of_iommu_configure_device(master_np, dev, id);
 	}
 
-	/*
-	 * Two success conditions can be represented by non-negative err here:
-	 * >0 : there is no IOMMU, or one was unavailable for non-fatal reasons
-	 *  0 : we found an IOMMU, and dev->fwspec is initialised appropriately
-	 * <0 : any actual error
-	 */
-	if (!err) {
-		/* The fwspec pointer changed, read it again */
-		fwspec = dev_iommu_fwspec_get(dev);
-		ops    = fwspec->ops;
-	}
-	/*
-	 * If we have reason to believe the IOMMU driver missed the initial
-	 * probe for dev, replay it to get things in order.
-	 */
-	if (!err && dev->bus)
-		err = iommu_probe_device(dev);
+	if (err == -ENODEV || err == -EPROBE_DEFER)
+		return err;
+	if (err)
+		goto err_log;
 
-	/* Ignore all other errors apart from EPROBE_DEFER */
-	if (err < 0) {
-		if (err == -EPROBE_DEFER)
-			return err;
-		dev_dbg(dev, "Adding to IOMMU failed: %d\n", err);
-		return -ENODEV;
-	}
-	if (!ops)
-		return -ENODEV;
+	err = iommu_probe_device(dev);
+	if (err)
+		goto err_log;
 	return 0;
+
+err_log:
+	dev_dbg(dev, "Adding to IOMMU failed: %d\n", err);
+	return err;
 }
 
 static enum iommu_resv_type __maybe_unused
-- 
2.42.0