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Commit e2f8d555 authored by Fabio Estevam's avatar Fabio Estevam Committed by David S. Miller
Browse files

net: fec: Fix division by zero 



commit 7f7d6c28 (net: fec: Ensure that initialization is done prior to
request_irq()) placed fec_ptp_init() into a point that ptp clock was not
available, which causes a division by zero in fec_ptp_start_cyclecounter():

[   17.895723] Division by zero in kernel.
[   17.899571] Backtrace:
[   17.902094] [<80012564>] (dump_backtrace+0x0/0x10c) from [<8056deec>]
(dump_stack+0x18/0x1c)
[   17.910539]  r6:bfba8500 r5:8075c950 r4:bfba8000 r3:bfbd0000
[   17.916284] [<8056ded4>] (dump_stack+0x0/0x1c) from [<80012688>]
(__div0+0x18/0x20)
[   17.923968] [<80012670>] (__div0+0x0/0x20) from [<802829c4>] (Ldiv0+0x8/0x10)
[   17.931140] [<80398534>] (fec_ptp_start_cyclecounter+0x0/0x110) from
[<80394f64>] (fec_restart+0x6c8/0x754)
[   17.940898] [<8039489c>] (fec_restart+0x0/0x754) from [<803969a0>]
(fec_enet_adjust_link+0xdc/0x108)
[   17.950046] [<803968c4>] (fec_enet_adjust_link+0x0/0x108) from [<80390bc4>]
(phy_state_machine+0x178/0x534)
...

Fix this by rearraging the code so that fec_ptp_init() is called only after
the clocks have been properly acquired.

Tested on both mx53 and mx6 platforms.

Reported-by: default avatarJim Baxter <jim_baxter@mentor.com>
Signed-off-by: default avatarFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2bb60cb9

drivers/net/ethernet/freescale/fec.c

+34 −34
Original line number Diff line number Diff line
@@ -1782,33 +1782,6 @@ fec_probe(struct platform_device *pdev) 
		fep->phy_interface = ret;

	}



	fep->bufdesc_ex =

		pdev->id_entry->driver_data & FEC_QUIRK_HAS_BUFDESC_EX;

	if (fep->bufdesc_ex)

		fec_ptp_init(ndev, pdev);



	ret = fec_enet_init(ndev);

	if (ret)

		goto failed_init;



	for (i = 0; i < FEC_IRQ_NUM; i++) {

		irq = platform_get_irq(pdev, i);

		if (irq < 0) {

			if (i)

				break;

			ret = irq;

			goto failed_irq;

		}

		ret = request_irq(irq, fec_enet_interrupt, IRQF_DISABLED, pdev->name, ndev);

		if (ret) {

			while (--i >= 0) {

				irq = platform_get_irq(pdev, i);

				free_irq(irq, ndev);

			}

			goto failed_irq;

		}

	}



	pinctrl = devm_pinctrl_get_select_default(&pdev->dev);

	if (IS_ERR(pinctrl)) {

		ret = PTR_ERR(pinctrl);
@@ -1828,6 +1801,8 @@ fec_probe(struct platform_device *pdev) 
	}



	fep->clk_ptp = devm_clk_get(&pdev->dev, "ptp");

	fep->bufdesc_ex =

		pdev->id_entry->driver_data & FEC_QUIRK_HAS_BUFDESC_EX;

	if (IS_ERR(fep->clk_ptp)) {

		ret = PTR_ERR(fep->clk_ptp);

		fep->bufdesc_ex = 0;
@@ -1850,6 +1825,31 @@ fec_probe(struct platform_device *pdev) 


	fec_reset_phy(pdev);



	if (fep->bufdesc_ex)

		fec_ptp_init(ndev, pdev);



	ret = fec_enet_init(ndev);

	if (ret)

		goto failed_init;



	for (i = 0; i < FEC_IRQ_NUM; i++) {

		irq = platform_get_irq(pdev, i);

		if (irq < 0) {

			if (i)

				break;

			ret = irq;

			goto failed_irq;

		}

		ret = request_irq(irq, fec_enet_interrupt, IRQF_DISABLED, pdev->name, ndev);

		if (ret) {

			while (--i >= 0) {

				irq = platform_get_irq(pdev, i);

				free_irq(irq, ndev);

			}

			goto failed_irq;

		}

	}



	ret = fec_enet_mii_init(pdev);

	if (ret)

		goto failed_mii_init;
@@ -1866,6 +1866,13 @@ fec_probe(struct platform_device *pdev) 
failed_register:

	fec_enet_mii_remove(fep);

failed_mii_init:

failed_init:

	for (i = 0; i < FEC_IRQ_NUM; i++) {

		irq = platform_get_irq(pdev, i);

		if (irq > 0)

			free_irq(irq, ndev);

	}

failed_irq:

failed_regulator:

	clk_disable_unprepare(fep->clk_ahb);

	clk_disable_unprepare(fep->clk_ipg);
@@ -1873,14 +1880,7 @@ fec_probe(struct platform_device *pdev) 
		clk_disable_unprepare(fep->clk_ptp);

failed_pin:

failed_clk:

	for (i = 0; i < FEC_IRQ_NUM; i++) {

		irq = platform_get_irq(pdev, i);

		if (irq > 0)

			free_irq(irq, ndev);

	}

failed_irq:

	iounmap(fep->hwp);

failed_init:

failed_ioremap:

	free_netdev(ndev);

failed_alloc_etherdev: