net/fsl_pq_mdio: Allow explicit speficition of TBIPA address

This introduces a simpler and generic method for for finding (and mapping)
the TBIPA register.

Instead of relying of complicated logic for finding the TBIPA register
address based on the MDIO or MII register block base
address, which even in some cases relies on undocumented shadow registers,
a second "reg" entry for the mdio bus devicetree node specifies the TBIPA
register.

Backwards compatibility is kept, as the existing logic is applied when
only a single "reg" mapping is specified.

Signed-off-by: Esben Haabendal <eha@deif.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/fsl-tsec-phy.txt

@@ -6,7 +6,11 @@ the definition of the PHY node in booting-without-of.txt for an example
 of how to define a PHY.
 
 Required properties:
-  - reg : Offset and length of the register set for the device
+  - reg : Offset and length of the register set for the device, and optionally
+          the offset and length of the TBIPA register (TBI PHY address
+	  register).  If TBIPA register is not specified, the driver will
+	  attempt to infer it from the register set specified (your mileage may
+	  vary).
   - compatible : Should define the compatible device type for the
     mdio. Currently supported strings/devices are:
 	- "fsl,gianfar-tbi"

drivers/net/ethernet/freescale/fsl_pq_mdio.c

@@ -377,6 +377,38 @@ static const struct of_device_id fsl_pq_mdio_match[] = {
 };
 MODULE_DEVICE_TABLE(of, fsl_pq_mdio_match);
 
+static void set_tbipa(const u32 tbipa_val, struct platform_device *pdev,
+		      uint32_t __iomem * (*get_tbipa)(void __iomem *),
+		      void __iomem *reg_map, struct resource *reg_res)
+{
+	struct device_node *np = pdev->dev.of_node;
+	uint32_t __iomem *tbipa;
+	bool tbipa_mapped;
+
+	tbipa = of_iomap(np, 1);
+	if (tbipa) {
+		tbipa_mapped = true;
+	} else {
+		tbipa_mapped = false;
+		tbipa = (*get_tbipa)(reg_map);
+
+		/*
+		 * Add consistency check to make sure TBI is contained within
+		 * the mapped range (not because we would get a segfault,
+		 * rather to catch bugs in computing TBI address). Print error
+		 * message but continue anyway.
+		 */
+		if ((void *)tbipa > reg_map + resource_size(reg_res) - 4)
+			dev_err(&pdev->dev, "invalid register map (should be at least 0x%04zx to contain TBI address)\n",
+				((void *)tbipa - reg_map) + 4);
+	}
+
+	iowrite32be(be32_to_cpu(tbipa_val), tbipa);
+
+	if (tbipa_mapped)
+		iounmap(tbipa);
+}
+
 static int fsl_pq_mdio_probe(struct platform_device *pdev)
 {
 	const struct of_device_id *id =
@@ -450,8 +482,6 @@ static int fsl_pq_mdio_probe(struct platform_device *pdev)
 
 		if (tbi) {
 			const u32 *prop = of_get_property(tbi, "reg", NULL);
-			uint32_t __iomem *tbipa;
-
 			if (!prop) {
 				dev_err(&pdev->dev,
 					"missing 'reg' property in node %pOF\n",
@@ -459,20 +489,8 @@ static int fsl_pq_mdio_probe(struct platform_device *pdev)
 				err = -EBUSY;
 				goto error;
 			}
-
+			set_tbipa(*prop, pdev,
-			tbipa = data->get_tbipa(priv->map);
+				  data->get_tbipa, priv->map, &res);
-
-			/*
-			 * Add consistency check to make sure TBI is contained
-			 * within the mapped range (not because we would get a
-			 * segfault, rather to catch bugs in computing TBI
-			 * address). Print error message but continue anyway.
-			 */
-			if ((void *)tbipa > priv->map + resource_size(&res) - 4)
-				dev_err(&pdev->dev, "invalid register map (should be at least 0x%04zx to contain TBI address)\n",
-					((void *)tbipa - priv->map) + 4);
-
-			iowrite32be(be32_to_cpup(prop), tbipa);
 		}
 	}