Hi Marek,
Am 07.03.24 um 12:41 schrieb Marek Szyprowski:
> On 05.03.2024 11:50, Jesper Nilsson wrote:
> > devm_request_irq() is called before we initialize the "variant"
> > member variable from of_device_get_match_data(), so if an interrupt
> > is triggered inbetween, we can end up following a NULL pointer
> > in the interrupt handler.
> >
> > This problem was exposed when the I2C controller in question was
> > (mis)configured to be used in both secure world and Linux.
> >
> > That this can happen is also reflected by the existing code that
> > clears any pending interrupts from "u-boot or misc causes".
> >
> > Move the clearing of pending interrupts and the call to
> > devm_request_irq() to the end of probe.
> >
> > Reviewed-by: Andi Shyti <andi.shyti@xxxxxxxxxx>
> > Fixes: 218e1496135e ("i2c: exynos5: add support for HSI2C on Exynos5260 SoC")
> > Signed-off-by: Jesper Nilsson <jesper.nilsson@xxxxxxxx>
> > ---
> > Changes in v3:
> > - Avoid multiple assignment
> > - Link to v2: https://lore.kernel.org/r/20240304-i2c_exynos5-v2-1-7b9c312be719@xxxxxxxx
> >
> > Changes in v2:
> > - Use dev_err_probe() instead of open coding it
> > - Dropped the return failure if we can't find a match in devicetree
> > - Link to v1: https://lore.kernel.org/r/20240304-i2c_exynos5-v1-1-e91c889d2025@xxxxxxxx
> > ---
> > drivers/i2c/busses/i2c-exynos5.c | 29 +++++++++++++++--------------
> > 1 file changed, 15 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-exynos5.c b/drivers/i2c/busses/i2c-exynos5.c
> > index 385ef9d9e4d4..8458e22313a7 100644
> > --- a/drivers/i2c/busses/i2c-exynos5.c
> > +++ b/drivers/i2c/busses/i2c-exynos5.c
> > @@ -906,23 +906,9 @@ static int exynos5_i2c_probe(struct platform_device *pdev)
> > i2c->adap.algo_data = i2c;
> > i2c->adap.dev.parent = &pdev->dev;
> >
> > - /* Clear pending interrupts from u-boot or misc causes */
> > - exynos5_i2c_clr_pend_irq(i2c);
> > -
> > spin_lock_init(&i2c->lock);
> > init_completion(&i2c->msg_complete);
> >
> > - i2c->irq = ret = platform_get_irq(pdev, 0);
> > - if (ret < 0)
> > - goto err_clk;
> > -
> > - ret = devm_request_irq(&pdev->dev, i2c->irq, exynos5_i2c_irq,
> > - IRQF_NO_SUSPEND, dev_name(&pdev->dev), i2c);
> > - if (ret != 0) {
> > - dev_err(&pdev->dev, "cannot request HS-I2C IRQ %d\n", i2c->irq);
> > - goto err_clk;
> > - }
> > -
> > i2c->variant = of_device_get_match_data(&pdev->dev);
> >
> > ret = exynos5_hsi2c_clock_setup(i2c);
> > @@ -940,6 +926,21 @@ static int exynos5_i2c_probe(struct platform_device *pdev)
> > clk_disable(i2c->clk);
> > clk_disable(i2c->pclk);
> >
> > + /* Clear pending interrupts from u-boot or misc causes */
> > + exynos5_i2c_clr_pend_irq(i2c);
>
> Just above this call the clocks have been disabled, so any access to the
> i2c host registers will result in freeze or external abort (depending on
> the soc/cpu).
>
> To make things worse, this patch moved registering the interrupt handler
> after the i2c_add_adapter() call. This means that all i2c devices that
> will be probbed directly from i2c_add_adapter() won't be able to access
> the i2c bus, as the host controller is still not fully functional that
> time yet.
>
> This breaks today's linux-next on all Exynos5+ platforms. Has anyone
> tested this change?
Tested this patch on top of stable 6.7.9, breaks booting odroid-xu4.
Gruß,
--
Markus
>
> > +
> > + ret = platform_get_irq(pdev, 0);
> > + if (ret < 0)
> > + goto err_clk;
> > + i2c->irq = ret;
> > +
> > + ret = devm_request_irq(&pdev->dev, i2c->irq, exynos5_i2c_irq,
> > + IRQF_NO_SUSPEND, dev_name(&pdev->dev), i2c);
> > + if (ret != 0) {
> > + dev_err(&pdev->dev, "cannot request HS-I2C IRQ %d\n", i2c->irq);
> > + goto err_clk;
> > + }
> > +
> > return 0;
> >
> > err_clk:
> >
> Best regards
