net: macb: Adjust tx_clk when link speed changes

Adjust the ethernet clock according to the negotiated link speed.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
index 603844b..419529a 100644 (file)
--- a/drivers/net/ethernet/cadence/macb.c
+++ b/drivers/net/ethernet/cadence/macb.c
@@ -204,6 +204,47 @@ static int macb_mdio_reset(struct mii_bus *bus)
        return 0;
 }
 
+/**
+ * macb_set_tx_clk() - Set a clock to a new frequency
+ * @clk                Pointer to the clock to change
+ * @rate       New frequency in Hz
+ * @dev                Pointer to the struct net_device
+ */
+static void macb_set_tx_clk(struct clk *clk, int speed, struct net_device *dev)
+{
+       long ferr, rate, rate_rounded;
+
+       switch (speed) {
+       case SPEED_10:
+               rate = 2500000;
+               break;
+       case SPEED_100:
+               rate = 25000000;
+               break;
+       case SPEED_1000:
+               rate = 125000000;
+               break;
+       default:
+               break;
+       }
+
+       rate_rounded = clk_round_rate(clk, rate);
+       if (rate_rounded < 0)
+               return;
+
+       /* RGMII allows 50 ppm frequency error. Test and warn if this limit
+        * is not satisfied.
+        */
+       ferr = abs(rate_rounded - rate);
+       ferr = DIV_ROUND_UP(ferr, rate / 100000);
+       if (ferr > 5)
+               netdev_warn(dev, "unable to generate target frequency: %ld Hz\n",
+                               rate);
+
+       if (clk_set_rate(clk, rate_rounded))
+               netdev_err(dev, "adjusting tx_clk failed.\n");
+}
+
 static void macb_handle_link_change(struct net_device *dev)
 {
        struct macb *bp = netdev_priv(dev);
@@ -251,6 +292,9 @@ static void macb_handle_link_change(struct net_device *dev)
 
        spin_unlock_irqrestore(&bp->lock, flags);
 
+       if (!IS_ERR(bp->tx_clk))
+               macb_set_tx_clk(bp->tx_clk, phydev->speed, dev);
+
        if (status_change) {
                if (phydev->link) {
                        netif_carrier_on(dev);
@@ -1805,6 +1849,8 @@ static int __init macb_probe(struct platform_device *pdev)
                goto err_out_free_dev;
        }
 
+       bp->tx_clk = devm_clk_get(&pdev->dev, "tx_clk");
+
        err = clk_prepare_enable(bp->pclk);
        if (err) {
                dev_err(&pdev->dev, "failed to enable pclk (%u)\n", err);
@@ -1817,6 +1863,15 @@ static int __init macb_probe(struct platform_device *pdev)
                goto err_out_disable_pclk;
        }
 
+       if (!IS_ERR(bp->tx_clk)) {
+               err = clk_prepare_enable(bp->tx_clk);
+               if (err) {
+                       dev_err(&pdev->dev, "failed to enable tx_clk (%u)\n",
+                                       err);
+                       goto err_out_disable_hclk;
+               }
+       }
+
        bp->regs = devm_ioremap(&pdev->dev, regs->start, resource_size(regs));
        if (!bp->regs) {
                dev_err(&pdev->dev, "failed to map registers, aborting.\n");
@@ -1917,6 +1972,9 @@ static int __init macb_probe(struct platform_device *pdev)
 err_out_unregister_netdev:
        unregister_netdev(dev);
 err_out_disable_clocks:
+       if (!IS_ERR(bp->tx_clk))
+               clk_disable_unprepare(bp->tx_clk);
+err_out_disable_hclk:
        clk_disable_unprepare(bp->hclk);
 err_out_disable_pclk:
        clk_disable_unprepare(bp->pclk);
@@ -1941,6 +1999,8 @@ static int __exit macb_remove(struct platform_device *pdev)
                kfree(bp->mii_bus->irq);
                mdiobus_free(bp->mii_bus);
                unregister_netdev(dev);
+               if (!IS_ERR(bp->tx_clk))
+                       clk_disable_unprepare(bp->tx_clk);
                clk_disable_unprepare(bp->hclk);
                clk_disable_unprepare(bp->pclk);
                free_netdev(dev);
@@ -1959,6 +2019,8 @@ static int macb_suspend(struct device *dev)
        netif_carrier_off(netdev);
        netif_device_detach(netdev);
 
+       if (!IS_ERR(bp->tx_clk))
+               clk_disable_unprepare(bp->tx_clk);
        clk_disable_unprepare(bp->hclk);
        clk_disable_unprepare(bp->pclk);
 
@@ -1973,6 +2035,8 @@ static int macb_resume(struct device *dev)
 
        clk_prepare_enable(bp->pclk);
        clk_prepare_enable(bp->hclk);
+       if (!IS_ERR(bp->tx_clk))
+               clk_prepare_enable(bp->tx_clk);
 
        netif_device_attach(netdev);
 

diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
index f407615..51c0244 100644 (file)
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -572,6 +572,7 @@ struct macb {
        struct platform_device  *pdev;
        struct clk              *pclk;
        struct clk              *hclk;
+       struct clk              *tx_clk;
        struct net_device       *dev;
        struct napi_struct      napi;
        struct work_struct      tx_error_task;