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net: fec: Ensure clocks are enabled while using mdio bus
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When a switch is attached to the mdio bus, the mdio bus can be used
while the interface is not open. If the IPG clock is not enabled, MDIO
reads/writes will simply time out.

Add support for runtime PM to control this clock. Enable/disable this
clock using runtime PM, with open()/close() and mdio read()/write()
function triggering runtime PM operations. Since PM is optional, the
IPG clock is enabled at probe and is no longer modified by
fec_enet_clk_enable(), thus if PM is not enabled in the kernel, it is
guaranteed the clock is running when MDIO operations are performed.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Cc: tyler.baker@linaro.org
Cc: fabio.estevam@freescale.com
Cc: shawn.guo@linaro.org
Tested-by: Fabio Estevam <fabio.estevam@freescale.com>
Tested-by: Tyler Baker <tyler.baker@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Andrew Lunn authored and David S. Miller committed Jul 27, 2015
1 parent 7025e88 commit 8fff755
Showing 1 changed file with 76 additions and 13 deletions.
89 changes: 76 additions & 13 deletions drivers/net/ethernet/freescale/fec_main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/pm_runtime.h>
#include <linux/ptrace.h>
#include <linux/errno.h>
#include <linux/ioport.h>
Expand Down Expand Up @@ -77,6 +78,7 @@ static void fec_enet_itr_coal_init(struct net_device *ndev);
#define FEC_ENET_RAEM_V 0x8
#define FEC_ENET_RAFL_V 0x8
#define FEC_ENET_OPD_V 0xFFF0
#define FEC_MDIO_PM_TIMEOUT 100 /* ms */

static struct platform_device_id fec_devtype[] = {
{
Expand Down Expand Up @@ -1767,7 +1769,13 @@ static void fec_enet_adjust_link(struct net_device *ndev)
static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
{
struct fec_enet_private *fep = bus->priv;
struct device *dev = &fep->pdev->dev;
unsigned long time_left;
int ret = 0;

ret = pm_runtime_get_sync(dev);
if (IS_ERR_VALUE(ret))
return ret;

fep->mii_timeout = 0;
init_completion(&fep->mdio_done);
Expand All @@ -1783,18 +1791,30 @@ static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
if (time_left == 0) {
fep->mii_timeout = 1;
netdev_err(fep->netdev, "MDIO read timeout\n");
return -ETIMEDOUT;
ret = -ETIMEDOUT;
goto out;
}

/* return value */
return FEC_MMFR_DATA(readl(fep->hwp + FEC_MII_DATA));
ret = FEC_MMFR_DATA(readl(fep->hwp + FEC_MII_DATA));

out:
pm_runtime_mark_last_busy(dev);
pm_runtime_put_autosuspend(dev);

return ret;
}

static int fec_enet_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
u16 value)
{
struct fec_enet_private *fep = bus->priv;
struct device *dev = &fep->pdev->dev;
unsigned long time_left;
int ret = 0;

ret = pm_runtime_get_sync(dev);
if (IS_ERR_VALUE(ret))
return ret;

fep->mii_timeout = 0;
init_completion(&fep->mdio_done);
Expand All @@ -1811,10 +1831,13 @@ static int fec_enet_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
if (time_left == 0) {
fep->mii_timeout = 1;
netdev_err(fep->netdev, "MDIO write timeout\n");
return -ETIMEDOUT;
ret = -ETIMEDOUT;
}

return 0;
pm_runtime_mark_last_busy(dev);
pm_runtime_put_autosuspend(dev);

return ret;
}

static int fec_enet_clk_enable(struct net_device *ndev, bool enable)
Expand All @@ -1826,9 +1849,6 @@ static int fec_enet_clk_enable(struct net_device *ndev, bool enable)
ret = clk_prepare_enable(fep->clk_ahb);
if (ret)
return ret;
ret = clk_prepare_enable(fep->clk_ipg);
if (ret)
goto failed_clk_ipg;
if (fep->clk_enet_out) {
ret = clk_prepare_enable(fep->clk_enet_out);
if (ret)
Expand All @@ -1852,7 +1872,6 @@ static int fec_enet_clk_enable(struct net_device *ndev, bool enable)
}
} else {
clk_disable_unprepare(fep->clk_ahb);
clk_disable_unprepare(fep->clk_ipg);
if (fep->clk_enet_out)
clk_disable_unprepare(fep->clk_enet_out);
if (fep->clk_ptp) {
Expand All @@ -1874,8 +1893,6 @@ static int fec_enet_clk_enable(struct net_device *ndev, bool enable)
if (fep->clk_enet_out)
clk_disable_unprepare(fep->clk_enet_out);
failed_clk_enet_out:
clk_disable_unprepare(fep->clk_ipg);
failed_clk_ipg:
clk_disable_unprepare(fep->clk_ahb);

return ret;
Expand Down Expand Up @@ -2847,10 +2864,14 @@ fec_enet_open(struct net_device *ndev)
struct fec_enet_private *fep = netdev_priv(ndev);
int ret;

ret = pm_runtime_get_sync(&fep->pdev->dev);
if (IS_ERR_VALUE(ret))
return ret;

pinctrl_pm_select_default_state(&fep->pdev->dev);
ret = fec_enet_clk_enable(ndev, true);
if (ret)
return ret;
goto clk_enable;

/* I should reset the ring buffers here, but I don't yet know
* a simple way to do that.
Expand Down Expand Up @@ -2881,6 +2902,9 @@ fec_enet_open(struct net_device *ndev)
fec_enet_free_buffers(ndev);
err_enet_alloc:
fec_enet_clk_enable(ndev, false);
clk_enable:
pm_runtime_mark_last_busy(&fep->pdev->dev);
pm_runtime_put_autosuspend(&fep->pdev->dev);
pinctrl_pm_select_sleep_state(&fep->pdev->dev);
return ret;
}
Expand All @@ -2903,6 +2927,9 @@ fec_enet_close(struct net_device *ndev)

fec_enet_clk_enable(ndev, false);
pinctrl_pm_select_sleep_state(&fep->pdev->dev);
pm_runtime_mark_last_busy(&fep->pdev->dev);
pm_runtime_put_autosuspend(&fep->pdev->dev);

fec_enet_free_buffers(ndev);

return 0;
Expand Down Expand Up @@ -3388,6 +3415,10 @@ fec_probe(struct platform_device *pdev)
if (ret)
goto failed_clk;

ret = clk_prepare_enable(fep->clk_ipg);
if (ret)
goto failed_clk_ipg;

fep->reg_phy = devm_regulator_get(&pdev->dev, "phy");
if (!IS_ERR(fep->reg_phy)) {
ret = regulator_enable(fep->reg_phy);
Expand All @@ -3400,6 +3431,11 @@ fec_probe(struct platform_device *pdev)
fep->reg_phy = NULL;
}

pm_runtime_set_autosuspend_delay(&pdev->dev, FEC_MDIO_PM_TIMEOUT);
pm_runtime_use_autosuspend(&pdev->dev);
pm_runtime_set_active(&pdev->dev);
pm_runtime_enable(&pdev->dev);

fec_reset_phy(pdev);

if (fep->bufdesc_ex)
Expand Down Expand Up @@ -3447,6 +3483,10 @@ fec_probe(struct platform_device *pdev)

fep->rx_copybreak = COPYBREAK_DEFAULT;
INIT_WORK(&fep->tx_timeout_work, fec_enet_timeout_work);

pm_runtime_mark_last_busy(&pdev->dev);
pm_runtime_put_autosuspend(&pdev->dev);

return 0;

failed_register:
Expand All @@ -3458,6 +3498,8 @@ fec_probe(struct platform_device *pdev)
if (fep->reg_phy)
regulator_disable(fep->reg_phy);
failed_regulator:
clk_disable_unprepare(fep->clk_ipg);
failed_clk_ipg:
fec_enet_clk_enable(ndev, false);
failed_clk:
failed_phy:
Expand Down Expand Up @@ -3567,7 +3609,28 @@ static int __maybe_unused fec_resume(struct device *dev)
return ret;
}

static SIMPLE_DEV_PM_OPS(fec_pm_ops, fec_suspend, fec_resume);
static int __maybe_unused fec_runtime_suspend(struct device *dev)
{
struct net_device *ndev = dev_get_drvdata(dev);
struct fec_enet_private *fep = netdev_priv(ndev);

clk_disable_unprepare(fep->clk_ipg);

return 0;
}

static int __maybe_unused fec_runtime_resume(struct device *dev)
{
struct net_device *ndev = dev_get_drvdata(dev);
struct fec_enet_private *fep = netdev_priv(ndev);

return clk_prepare_enable(fep->clk_ipg);
}

static const struct dev_pm_ops fec_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(fec_suspend, fec_resume)
SET_RUNTIME_PM_OPS(fec_runtime_suspend, fec_runtime_resume, NULL)
};

static struct platform_driver fec_driver = {
.driver = {
Expand Down

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