• Nicolas Boichat's avatar
    pinctrl: mediatek: Update cur_mask in mask/mask ops · 056432be
    Nicolas Boichat authored
    [ Upstream commit 9d957a95 ]
    
    During suspend/resume, mtk_eint_mask may be called while
    wake_mask is active. For example, this happens if a wake-source
    with an active interrupt handler wakes the system:
    irq/pm.c:irq_pm_check_wakeup would disable the interrupt, so
    that it can be handled later on in the resume flow.
    
    However, this may happen before mtk_eint_do_resume is called:
    in this case, wake_mask is loaded, and cur_mask is restored
    from an older copy, re-enabling the interrupt, and causing
    an interrupt storm (especially for level interrupts).
    
    Step by step, for a line that has both wake and interrupt enabled:
     1. cur_mask[irq] = 1; wake_mask[irq] = 1; EINT_EN[irq] = 1 (interrupt
        enabled at hardware level)
     2. System suspends, resumes due to that line (at this stage EINT_EN
        == wake_mask)
     3. irq_pm_check_wakeup is called, and disables the interrupt =>
        EINT_EN[irq] = 0, but we still have cur_mask[irq] = 1
     4. mtk_eint_do_resume is called, and restores EINT_EN = cur_mask, so
        it reenables EINT_EN[irq] = 1 => interrupt storm as the driver
        is not yet ready to handle the interrupt.
    
    This patch fixes the issue in step 3, by recording all mask/unmask
    changes in cur_mask. This also avoids the need to read the current
    mask in eint_do_suspend, and we can remove mtk_eint_chip_read_mask
    function.
    
    The interrupt will be re-enabled properly later on, sometimes after
    mtk_eint_do_resume, when the driver is ready to handle it.
    
    Fixes: 58a5e1b6 ("pinctrl: mediatek: Implement wake handler and suspend resume")
    Signed-off-by: default avatarNicolas Boichat <drinkcat@chromium.org>
    Acked-by: default avatarSean Wang <sean.wang@kernel.org>
    Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
    Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
    056432be
mtk-eint.c 12 KB