From ee975351cf0c2a11cdf97eae58265c126cb32850 Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Mon, 19 Feb 2024 12:40:51 -0800 Subject: net: mdio: mdio-bcm-unimac: Manage clock around I/O accesses Up until now we have managed not to have the mdio-bcm-unimac manage its clock except during probe and suspend/resume. This works most of the time, except where it does not. With a fully modular build, we can get into a situation whereby the GENET driver is fully registered, and so is the mdio-bcm-unimac driver, however the Ethernet PHY driver is not yet, because it depends on a resource that is not yet available (e.g.: GPIO provider). In that state, the network device is not usable yet, and so to conserve power, the GENET driver will have turned off its "main" clock which feeds its MDIO controller. When the PHY driver finally probes however, we make an access to the PHY registers to e.g.: disable interrupts, and this causes a bus error within the MDIO controller space because the MDIO controller clock(s) are turned off. To remedy that, we manage the clock around all of the I/O accesses to the hardware which are done exclusively during read, write and clock divider configuration. This ensures that the register space is accessible, and this also ensures that there are not unnecessarily elevated reference counts keeping the clocks active when the network device is administratively turned off. It would be the case with the previous way of managing the clock. Reviewed-by: Jacob Keller Signed-off-by: Florian Fainelli Signed-off-by: David S. Miller --- drivers/net/mdio/mdio-bcm-unimac.c | 93 ++++++++++++++------------- include/linux/platform_data/mdio-bcm-unimac.h | 3 + 2 files changed, 53 insertions(+), 43 deletions(-) diff --git a/drivers/net/mdio/mdio-bcm-unimac.c b/drivers/net/mdio/mdio-bcm-unimac.c index 68f8ee0ec8ba..6fe08427fdd4 100644 --- a/drivers/net/mdio/mdio-bcm-unimac.c +++ b/drivers/net/mdio/mdio-bcm-unimac.c @@ -94,6 +94,10 @@ static int unimac_mdio_read(struct mii_bus *bus, int phy_id, int reg) int ret; u32 cmd; + ret = clk_prepare_enable(priv->clk); + if (ret) + return ret; + /* Prepare the read operation */ cmd = MDIO_RD | (phy_id << MDIO_PMD_SHIFT) | (reg << MDIO_REG_SHIFT); unimac_mdio_writel(priv, cmd, MDIO_CMD); @@ -103,7 +107,7 @@ static int unimac_mdio_read(struct mii_bus *bus, int phy_id, int reg) ret = priv->wait_func(priv->wait_func_data); if (ret) - return ret; + goto out; cmd = unimac_mdio_readl(priv, MDIO_CMD); @@ -112,10 +116,15 @@ static int unimac_mdio_read(struct mii_bus *bus, int phy_id, int reg) * that condition here and ignore the MDIO controller read failure * indication. */ - if (!(bus->phy_ignore_ta_mask & 1 << phy_id) && (cmd & MDIO_READ_FAIL)) - return -EIO; + if (!(bus->phy_ignore_ta_mask & 1 << phy_id) && (cmd & MDIO_READ_FAIL)) { + ret = -EIO; + goto out; + } - return cmd & 0xffff; + ret = cmd & 0xffff; +out: + clk_disable_unprepare(priv->clk); + return ret; } static int unimac_mdio_write(struct mii_bus *bus, int phy_id, @@ -123,6 +132,11 @@ static int unimac_mdio_write(struct mii_bus *bus, int phy_id, { struct unimac_mdio_priv *priv = bus->priv; u32 cmd; + int ret; + + ret = clk_prepare_enable(priv->clk); + if (ret) + return ret; /* Prepare the write operation */ cmd = MDIO_WR | (phy_id << MDIO_PMD_SHIFT) | @@ -131,7 +145,10 @@ static int unimac_mdio_write(struct mii_bus *bus, int phy_id, unimac_mdio_start(priv); - return priv->wait_func(priv->wait_func_data); + ret = priv->wait_func(priv->wait_func_data); + clk_disable_unprepare(priv->clk); + + return ret; } /* Workaround for integrated BCM7xxx Gigabit PHYs which have a problem with @@ -178,14 +195,19 @@ static int unimac_mdio_reset(struct mii_bus *bus) return 0; } -static void unimac_mdio_clk_set(struct unimac_mdio_priv *priv) +static int unimac_mdio_clk_set(struct unimac_mdio_priv *priv) { unsigned long rate; u32 reg, div; + int ret; /* Keep the hardware default values */ if (!priv->clk_freq) - return; + return 0; + + ret = clk_prepare_enable(priv->clk); + if (ret) + return ret; if (!priv->clk) rate = 250000000; @@ -195,7 +217,8 @@ static void unimac_mdio_clk_set(struct unimac_mdio_priv *priv) div = (rate / (2 * priv->clk_freq)) - 1; if (div & ~MDIO_CLK_DIV_MASK) { pr_warn("Incorrect MDIO clock frequency, ignoring\n"); - return; + ret = 0; + goto out; } /* The MDIO clock is the reference clock (typically 250Mhz) divided by @@ -205,6 +228,9 @@ static void unimac_mdio_clk_set(struct unimac_mdio_priv *priv) reg &= ~(MDIO_CLK_DIV_MASK << MDIO_CLK_DIV_SHIFT); reg |= div << MDIO_CLK_DIV_SHIFT; unimac_mdio_writel(priv, reg, MDIO_CFG); +out: + clk_disable_unprepare(priv->clk); + return ret; } static int unimac_mdio_probe(struct platform_device *pdev) @@ -235,24 +261,12 @@ static int unimac_mdio_probe(struct platform_device *pdev) return -ENOMEM; } - priv->clk = devm_clk_get_optional(&pdev->dev, NULL); - if (IS_ERR(priv->clk)) - return PTR_ERR(priv->clk); - - ret = clk_prepare_enable(priv->clk); - if (ret) - return ret; - if (of_property_read_u32(np, "clock-frequency", &priv->clk_freq)) priv->clk_freq = 0; - unimac_mdio_clk_set(priv); - priv->mii_bus = mdiobus_alloc(); - if (!priv->mii_bus) { - ret = -ENOMEM; - goto out_clk_disable; - } + if (!priv->mii_bus) + return -ENOMEM; bus = priv->mii_bus; bus->priv = priv; @@ -261,17 +275,29 @@ static int unimac_mdio_probe(struct platform_device *pdev) priv->wait_func = pdata->wait_func; priv->wait_func_data = pdata->wait_func_data; bus->phy_mask = ~pdata->phy_mask; + priv->clk = pdata->clk; } else { bus->name = "unimac MII bus"; priv->wait_func_data = priv; priv->wait_func = unimac_mdio_poll; + priv->clk = devm_clk_get_optional(&pdev->dev, NULL); + } + + if (IS_ERR(priv->clk)) { + ret = PTR_ERR(priv->clk); + goto out_mdio_free; } + bus->parent = &pdev->dev; bus->read = unimac_mdio_read; bus->write = unimac_mdio_write; bus->reset = unimac_mdio_reset; snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d", pdev->name, pdev->id); + ret = unimac_mdio_clk_set(priv); + if (ret) + goto out_mdio_free; + ret = of_mdiobus_register(bus, np); if (ret) { dev_err(&pdev->dev, "MDIO bus registration failed\n"); @@ -286,8 +312,6 @@ static int unimac_mdio_probe(struct platform_device *pdev) out_mdio_free: mdiobus_free(bus); -out_clk_disable: - clk_disable_unprepare(priv->clk); return ret; } @@ -297,34 +321,17 @@ static void unimac_mdio_remove(struct platform_device *pdev) mdiobus_unregister(priv->mii_bus); mdiobus_free(priv->mii_bus); - clk_disable_unprepare(priv->clk); -} - -static int __maybe_unused unimac_mdio_suspend(struct device *d) -{ - struct unimac_mdio_priv *priv = dev_get_drvdata(d); - - clk_disable_unprepare(priv->clk); - - return 0; } static int __maybe_unused unimac_mdio_resume(struct device *d) { struct unimac_mdio_priv *priv = dev_get_drvdata(d); - int ret; - ret = clk_prepare_enable(priv->clk); - if (ret) - return ret; - - unimac_mdio_clk_set(priv); - - return 0; + return unimac_mdio_clk_set(priv); } static SIMPLE_DEV_PM_OPS(unimac_mdio_pm_ops, - unimac_mdio_suspend, unimac_mdio_resume); + NULL, unimac_mdio_resume); static const struct of_device_id unimac_mdio_ids[] = { { .compatible = "brcm,asp-v2.1-mdio", }, diff --git a/include/linux/platform_data/mdio-bcm-unimac.h b/include/linux/platform_data/mdio-bcm-unimac.h index 8a5f9f0b2c52..724e1f57b81f 100644 --- a/include/linux/platform_data/mdio-bcm-unimac.h +++ b/include/linux/platform_data/mdio-bcm-unimac.h @@ -1,11 +1,14 @@ #ifndef __MDIO_BCM_UNIMAC_PDATA_H #define __MDIO_BCM_UNIMAC_PDATA_H +struct clk; + struct unimac_mdio_pdata { u32 phy_mask; int (*wait_func)(void *data); void *wait_func_data; const char *bus_name; + struct clk *clk; }; #define UNIMAC_MDIO_DRV_NAME "unimac-mdio" -- cgit From ee2b4cf8b281606bbf332cbd73ce2a73eac417f0 Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Mon, 19 Feb 2024 12:40:52 -0800 Subject: net: bcmgenet: Pass "main" clock down to the MDIO driver GENET has historically had to create a MDIO platform device for its controller and pass some auxiliary data to it, like a MDIO completion callback. Now we also pass the "main" clock to allow for the MDIO bus controller to manage that clock adequately around I/O accesses. Reviewed-by: Jacob Keller Signed-off-by: Florian Fainelli Signed-off-by: David S. Miller --- drivers/net/ethernet/broadcom/genet/bcmmii.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/net/ethernet/broadcom/genet/bcmmii.c b/drivers/net/ethernet/broadcom/genet/bcmmii.c index cbbe004621bc..7a21950da77c 100644 --- a/drivers/net/ethernet/broadcom/genet/bcmmii.c +++ b/drivers/net/ethernet/broadcom/genet/bcmmii.c @@ -476,6 +476,10 @@ static int bcmgenet_mii_register(struct bcmgenet_priv *priv) ppd.wait_func = bcmgenet_mii_wait; ppd.wait_func_data = priv; ppd.bus_name = "bcmgenet MII bus"; + /* Pass a reference to our "main" clock which is used for MDIO + * transfers + */ + ppd.clk = priv->clk; /* Unimac MDIO bus controller starts at UniMAC offset + MDIO_CMD * and is 2 * 32-bits word long, 8 bytes total. -- cgit From ba0b78371c46b2104197ff2c244f13f011ddfa80 Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Mon, 19 Feb 2024 12:40:53 -0800 Subject: Revert "net: bcmgenet: Ensure MDIO unregistration has clocks enabled" This reverts commit 1b5ea7ffb7a3bdfffb4b7f40ce0d20a3372ee405 ("net: bcmgenet: Ensure MDIO unregistration has clocks enabled"). This is no longer necessary now that the MDIO bus controller has a clock that it can manage around the I/O accesses. Reviewed-by: Jacob Keller Signed-off-by: Florian Fainelli Signed-off-by: David S. Miller --- drivers/net/ethernet/broadcom/genet/bcmmii.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/net/ethernet/broadcom/genet/bcmmii.c b/drivers/net/ethernet/broadcom/genet/bcmmii.c index 7a21950da77c..9ada89355747 100644 --- a/drivers/net/ethernet/broadcom/genet/bcmmii.c +++ b/drivers/net/ethernet/broadcom/genet/bcmmii.c @@ -678,7 +678,5 @@ void bcmgenet_mii_exit(struct net_device *dev) if (of_phy_is_fixed_link(dn)) of_phy_deregister_fixed_link(dn); of_node_put(priv->phy_dn); - clk_prepare_enable(priv->clk); platform_device_unregister(priv->mii_pdev); - clk_disable_unprepare(priv->clk); } -- cgit