net/fsl: modify xgmac_mdio for little endian SoCs

MDIO controller on little endian Socs, e.g. ls2085a is similar to the
controller on big endian Socs, but the MDIO access is little endian,
we use I/O accessor function to handle endianness, so the driver can
run on little endian Socs. A property "little-endian" is used
in DTS to indicate the MDIO is little endian, if driver probes the
property, driver will access MDIO in little endian, otherwise, driver
works in big endian by default.
Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/xgmac_mdio.c

@@ -46,17 +46,43 @@ struct tgec_mdio_controller {
 #define MDIO_DATA(x)		(x & 0xffff)
 #define MDIO_DATA_BSY		BIT(31)
 
+struct mdio_fsl_priv {
+	struct	tgec_mdio_controller __iomem *mdio_base;
+	bool	is_little_endian;
+};
+
+static u32 xgmac_read32(void __iomem *regs,
+			bool is_little_endian)
+{
+	if (is_little_endian)
+		return ioread32(regs);
+	else
+		return ioread32be(regs);
+}
+
+static void xgmac_write32(u32 value,
+			  void __iomem *regs,
+			  bool is_little_endian)
+{
+	if (is_little_endian)
+		iowrite32(value, regs);
+	else
+		iowrite32be(value, regs);
+}
+
 /*
  * Wait until the MDIO bus is free
  */
 static int xgmac_wait_until_free(struct device *dev,
-				 struct tgec_mdio_controller __iomem *regs)
+				 struct tgec_mdio_controller __iomem *regs,
+				 bool is_little_endian)
 {
 	unsigned int timeout;
 
 	/* Wait till the bus is free */
 	timeout = TIMEOUT;
-	while ((ioread32be(&regs->mdio_stat) & MDIO_STAT_BSY) && timeout) {
+	while ((xgmac_read32(&regs->mdio_stat, is_little_endian) &
+		MDIO_STAT_BSY) && timeout) {
 		cpu_relax();
 		timeout--;
 	}
@@ -73,13 +99,15 @@ static int xgmac_wait_until_free(struct device *dev,
  * Wait till the MDIO read or write operation is complete
  */
 static int xgmac_wait_until_done(struct device *dev,
-				 struct tgec_mdio_controller __iomem *regs)
+				 struct tgec_mdio_controller __iomem *regs,
+				 bool is_little_endian)
 {
 	unsigned int timeout;
 
 	/* Wait till the MDIO write is complete */
 	timeout = TIMEOUT;
-	while ((ioread32be(&regs->mdio_stat) & MDIO_STAT_BSY) && timeout) {
+	while ((xgmac_read32(&regs->mdio_stat, is_little_endian) &
+		MDIO_STAT_BSY) && timeout) {
 		cpu_relax();
 		timeout--;
 	}
@@ -99,12 +127,14 @@ static int xgmac_wait_until_done(struct device *dev,
  */
 static int xgmac_mdio_write(struct mii_bus *bus, int phy_id, int regnum, u16 value)
 {
-	struct tgec_mdio_controller __iomem *regs = bus->priv;
+	struct mdio_fsl_priv *priv = (struct mdio_fsl_priv *)bus->priv;
+	struct tgec_mdio_controller __iomem *regs = priv->mdio_base;
 	uint16_t dev_addr;
 	u32 mdio_ctl, mdio_stat;
 	int ret;
+	bool endian = priv->is_little_endian;
 
-	mdio_stat = ioread32be(&regs->mdio_stat);
+	mdio_stat = xgmac_read32(&regs->mdio_stat, endian);
 	if (regnum & MII_ADDR_C45) {
 		/* Clause 45 (ie 10G) */
 		dev_addr = (regnum >> 16) & 0x1f;
@@ -115,29 +145,29 @@ static int xgmac_mdio_write(struct mii_bus *bus, int phy_id, int regnum, u16 val
 		mdio_stat &= ~MDIO_STAT_ENC;
 	}
 
-	iowrite32be(mdio_stat, &regs->mdio_stat);
+	xgmac_write32(mdio_stat, &regs->mdio_stat, endian);
 
-	ret = xgmac_wait_until_free(&bus->dev, regs);
+	ret = xgmac_wait_until_free(&bus->dev, regs, endian);
 	if (ret)
 		return ret;
 
 	/* Set the port and dev addr */
 	mdio_ctl = MDIO_CTL_PORT_ADDR(phy_id) | MDIO_CTL_DEV_ADDR(dev_addr);
-	iowrite32be(mdio_ctl, &regs->mdio_ctl);
+	xgmac_write32(mdio_ctl, &regs->mdio_ctl, endian);
 
 	/* Set the register address */
 	if (regnum & MII_ADDR_C45) {
-		iowrite32be(regnum & 0xffff, &regs->mdio_addr);
+		xgmac_write32(regnum & 0xffff, &regs->mdio_addr, endian);
 
-		ret = xgmac_wait_until_free(&bus->dev, regs);
+		ret = xgmac_wait_until_free(&bus->dev, regs, endian);
 		if (ret)
 			return ret;
 	}
 
 	/* Write the value to the register */
-	iowrite32be(MDIO_DATA(value), &regs->mdio_data);
+	xgmac_write32(MDIO_DATA(value), &regs->mdio_data, endian);
 
-	ret = xgmac_wait_until_done(&bus->dev, regs);
+	ret = xgmac_wait_until_done(&bus->dev, regs, endian);
 	if (ret)
 		return ret;
 
@@ -151,14 +181,16 @@ static int xgmac_mdio_write(struct mii_bus *bus, int phy_id, int regnum, u16 val
  */
 static int xgmac_mdio_read(struct mii_bus *bus, int phy_id, int regnum)
 {
-	struct tgec_mdio_controller __iomem *regs = bus->priv;
+	struct mdio_fsl_priv *priv = (struct mdio_fsl_priv *)bus->priv;
+	struct tgec_mdio_controller __iomem *regs = priv->mdio_base;
 	uint16_t dev_addr;
 	uint32_t mdio_stat;
 	uint32_t mdio_ctl;
 	uint16_t value;
 	int ret;
+	bool endian = priv->is_little_endian;
 
-	mdio_stat = ioread32be(&regs->mdio_stat);
+	mdio_stat = xgmac_read32(&regs->mdio_stat, endian);
 	if (regnum & MII_ADDR_C45) {
 		dev_addr = (regnum >> 16) & 0x1f;
 		mdio_stat |= MDIO_STAT_ENC;
@@ -167,41 +199,41 @@ static int xgmac_mdio_read(struct mii_bus *bus, int phy_id, int regnum)
 		mdio_stat &= ~MDIO_STAT_ENC;
 	}
 
-	iowrite32be(mdio_stat, &regs->mdio_stat);
+	xgmac_write32(mdio_stat, &regs->mdio_stat, endian);
 
-	ret = xgmac_wait_until_free(&bus->dev, regs);
+	ret = xgmac_wait_until_free(&bus->dev, regs, endian);
 	if (ret)
 		return ret;
 
 	/* Set the Port and Device Addrs */
 	mdio_ctl = MDIO_CTL_PORT_ADDR(phy_id) | MDIO_CTL_DEV_ADDR(dev_addr);
-	iowrite32be(mdio_ctl, &regs->mdio_ctl);
+	xgmac_write32(mdio_ctl, &regs->mdio_ctl, endian);
 
 	/* Set the register address */
 	if (regnum & MII_ADDR_C45) {
-		iowrite32be(regnum & 0xffff, &regs->mdio_addr);
+		xgmac_write32(regnum & 0xffff, &regs->mdio_addr, endian);
 
-		ret = xgmac_wait_until_free(&bus->dev, regs);
+		ret = xgmac_wait_until_free(&bus->dev, regs, endian);
 		if (ret)
 			return ret;
 	}
 
 	/* Initiate the read */
-	iowrite32be(mdio_ctl | MDIO_CTL_READ, &regs->mdio_ctl);
+	xgmac_write32(mdio_ctl | MDIO_CTL_READ, &regs->mdio_ctl, endian);
 
-	ret = xgmac_wait_until_done(&bus->dev, regs);
+	ret = xgmac_wait_until_done(&bus->dev, regs, endian);
 	if (ret)
 		return ret;
 
 	/* Return all Fs if nothing was there */
-	if (ioread32be(&regs->mdio_stat) & MDIO_STAT_RD_ER) {
+	if (xgmac_read32(&regs->mdio_stat, endian) & MDIO_STAT_RD_ER) {
 		dev_err(&bus->dev,
 			"Error while reading PHY%d reg at %d.%hhu\n",
 			phy_id, dev_addr, regnum);
 		return 0xffff;
 	}
 
-	value = ioread32be(&regs->mdio_data) & 0xffff;
+	value = xgmac_read32(&regs->mdio_data, endian) & 0xffff;
 	dev_dbg(&bus->dev, "read %04x\n", value);
 
 	return value;
@@ -212,6 +244,7 @@ static int xgmac_mdio_probe(struct platform_device *pdev)
 	struct device_node *np = pdev->dev.of_node;
 	struct mii_bus *bus;
 	struct resource res;
+	struct mdio_fsl_priv *priv;
 	int ret;
 
 	ret = of_address_to_resource(np, 0, &res);
@@ -220,7 +253,7 @@ static int xgmac_mdio_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	bus = mdiobus_alloc();
+	bus = mdiobus_alloc_size(sizeof(struct mdio_fsl_priv));
 	if (!bus)
 		return -ENOMEM;
 
@@ -231,12 +264,19 @@ static int xgmac_mdio_probe(struct platform_device *pdev)
 	snprintf(bus->id, MII_BUS_ID_SIZE, "%llx", (unsigned long long)res.start);
 
 	/* Set the PHY base address */
-	bus->priv = of_iomap(np, 0);
-	if (!bus->priv) {
+	priv = bus->priv;
+	priv->mdio_base = of_iomap(np, 0);
+	if (!priv->mdio_base) {
 		ret = -ENOMEM;
 		goto err_ioremap;
 	}
 
+	if (of_get_property(pdev->dev.of_node,
+			    "little-endian", NULL))
+		priv->is_little_endian = true;
+	else
+		priv->is_little_endian = false;
+
 	ret = of_mdiobus_register(bus, np);
 	if (ret) {
 		dev_err(&pdev->dev, "cannot register MDIO bus\n");
@@ -248,7 +288,7 @@ static int xgmac_mdio_probe(struct platform_device *pdev)
 	return 0;
 
 err_registration:
-	iounmap(bus->priv);
+	iounmap(priv->mdio_base);
 
 err_ioremap:
 	mdiobus_free(bus);