Commit ca61ba38 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'rework-genet-mdioclocking' 



Florian Fainelli says:

====================
Rework GENET MDIO controller clocking

This patch series reworks the way that we manage the GENET MDIO
controller clocks around I/O accesses. During testing with a fully
modular build where bcmgenet, mdio-bcm-unimac, and the Broadcom PHY
driver (broadcom) are all loaded as modules, with no particular care
being taken to order them to mimize deferred probing the following bus
error was obtained:

[    4.344831] printk: console [ttyS0] enabled
[    4.351102] 840d000.serial: ttyS1 at MMIO 0x840d000 (irq = 29, base_baud = 5062500) is a Broadcom BCM7271 UART
[    4.363110] 840e000.serial: ttyS2 at MMIO 0x840e000 (irq = 30, base_baud = 5062500) is a Broadcom BCM7271 UART
[    4.387392] iproc-rng200 8402000.rng: hwrng registered
[    4.398012] Consider using thermal netlink events interface
[    4.403717] brcmstb_thermal a581500.thermal: registered AVS TMON of-sensor driver
[    4.440085] bcmgenet 8f00000.ethernet: GENET 5.0 EPHY: 0x0000
[    4.482526] unimac-mdio unimac-mdio.0: Broadcom UniMAC MDIO bus
[    4.514019] bridge: filtering via arp/ip/ip6tables is no longer available by default. Update your scripts to load br_netfilter if you need this.
[    4.551304] SError Interrupt on CPU2, code 0x00000000bf000002 -- SError
[    4.551324] CPU: 2 PID: 8 Comm: kworker/u8:0 Not tainted 6.1.53-0.1pre-g5a26d98e908c #2
[    4.551330] Hardware name: BCM972180HB_V20 (DT)
[    4.551336] Workqueue: events_unbound deferred_probe_work_func
[    4.551363] pstate: 00000005 (nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[    4.551368] pc : el1_abort+0x2c/0x58
[    4.551376] lr : el1_abort+0x20/0x58
[    4.551379] sp : ffffffc00a383960
[    4.551380] x29: ffffffc00a383960 x28: ffffff80029fd780 x27: 0000000000000000
[    4.551385] x26: 0000000000000000 x25: ffffff8002839005 x24: ffffffc00a1f9bd0
[    4.551390] x23: 0000000040000005 x22: ffffffc000a48084 x21: ffffffc00a3dde14
[    4.551394] x20: 0000000096000210 x19: ffffffc00a3839a0 x18: 0000000000000579
[    4.551399] x17: 0000000000000000 x16: 0000000100000000 x15: ffffffc00a3838c0
[    4.551403] x14: 000000000000000a x13: 6e69622f7273752f x12: 3a6e6962732f7273
[    4.551408] x11: 752f3a6e69622f3a x10: 6e6962732f3d4854 x9 : ffffffc0086466a8
[    4.551412] x8 : ffffff80049ee100 x7 : ffffff8003231938 x6 : 0000000000000000
[    4.551416] x5 : 0000002200000000 x4 : ffffffc00a3839a0 x3 : 0000002000000000
[    4.551420] x2 : 0000000000000025 x1 : 0000000096000210 x0 : 0000000000000000
[    4.551429] Kernel panic - not syncing: Asynchronous SError Interrupt
[    4.551432] CPU: 2 PID: 8 Comm: kworker/u8:0 Not tainted 6.1.53-0.1pre-g5a26d98e908c #2
[    4.551435] Hardware name: BCM972180HB_V20 (DT)
[    4.551437] Workqueue: events_unbound deferred_probe_work_func
[    4.551443] Call trace:
[    4.551445]  dump_backtrace+0xe4/0x124
[    4.551452]  show_stack+0x1c/0x28
[    4.551455]  dump_stack_lvl+0x60/0x78
[    4.551462]  dump_stack+0x14/0x2c
[    4.551467]  panic+0x134/0x304
[    4.551472]  nmi_panic+0x50/0x70
[    4.551480]  arm64_serror_panic+0x70/0x7c
[    4.551484]  do_serror+0x2c/0x5c
[    4.551487]  el1h_64_error_handler+0x2c/0x40
[    4.551491]  el1h_64_error+0x64/0x68
[    4.551496]  el1_abort+0x2c/0x58
[    4.551499]  el1h_64_sync_handler+0x8c/0xb4
[    4.551502]  el1h_64_sync+0x64/0x68
[    4.551505]  unimac_mdio_readl.isra.0+0x4/0xc [mdio_bcm_unimac]
[    4.551519]  __mdiobus_read+0x2c/0x88
[    4.551526]  mdiobus_read+0x40/0x60
[    4.551530]  phy_read+0x18/0x20
[    4.551534]  bcm_phy_config_intr+0x20/0x84
[    4.551537]  phy_disable_interrupts+0x2c/0x3c
[    4.551543]  phy_probe+0x80/0x1b0
[    4.551545]  really_probe+0x1b8/0x390
[    4.551550]  __driver_probe_device+0x134/0x14c
[    4.551554]  driver_probe_device+0x40/0xf8
[    4.551559]  __device_attach_driver+0x108/0x11c
[    4.551563]  bus_for_each_drv+0xa4/0xcc
[    4.551567]  __device_attach+0xdc/0x190
[    4.551571]  device_initial_probe+0x18/0x20
[    4.551575]  bus_probe_device+0x34/0x94
[    4.551579]  deferred_probe_work_func+0xd4/0xe8
[    4.551583]  process_one_work+0x1ac/0x25c
[    4.551590]  worker_thread+0x1f4/0x260
[    4.551595]  kthread+0xc0/0xd0
[    4.551600]  ret_from_fork+0x10/0x20
[    4.551608] SMP: stopping secondary CPUs
[    4.551617] Kernel Offset: disabled
[    4.551619] CPU features: 0x00000,00c00080,0000420b
[    4.551622] Memory Limit: none
[    4.833838] ---[ end Kernel panic - not syncing: Asynchronous SError Interrupt ]---

The issue here is that we managed to probe the GENET controller, the
mdio-bcm-unimac MDIO controller, but the PHY was still being held in a
probe deferral state because it depended upon a GPIO controller provider
not loaded yet. As soon as that provider is loaded however, the PHY
continues to probe, tries to disable the interrupts, and this causes a
MDIO transaction. That MDIO transaction requires I/O register accesses
within the GENET's larger block, and since its clocks are turned off,
the CPU gets a bus error signaled as a System Error.

The patch series takes the simplest approach of keeping the clocks
enabled just for the duration of the I/O accesses. This is also
beneficial to other drivers like bcmasp2 which make use of the same MDIO
controller driver.

Changes in v2:

- added missing ret assignment in the if (IS_ERR(priv->clk)) branch

- added Jacob's R-by tags

- corrected the commit ID being reverted in patch #3
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 78b88ef3 ba0b7837

drivers/net/ethernet/broadcom/genet/bcmmii.c

+4 −2
Original line number Diff line number Diff line
@@ -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.
@@ -674,7 +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);

}

drivers/net/mdio/mdio-bcm-unimac.c

+50 −43
Original line number Diff line number Diff line
@@ -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", },

include/linux/platform_data/mdio-bcm-unimac.h

+3 −0
Original line number Diff line number Diff line 
#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"