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pinctrl: mediatek: Update cur_mask in mask/mask ops 

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: 58a5e1b64b ("pinctrl: mediatek: Implement wake handler and suspend resume")
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Acked-by: Sean Wang <sean.wang@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Nicolas Boichat 2019-06-26 11:54:45 +08:00 committed by Linus Walleij
parent 35594bc7ce
commit 9d957a959b
1 changed files with 4 additions and 14 deletions
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18
drivers/pinctrl/mediatek/mtk-eint.c
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@ -113,6 +113,8 @@ static void mtk_eint_mask(struct irq_data *d)
void __iomem *reg = mtk_eint_get_offset(eint, d->hwirq,
eint->regs->mask_set);
eint->cur_mask[d->hwirq >> 5] &= ~mask;
writel(mask, reg);
}
@ -123,6 +125,8 @@ static void mtk_eint_unmask(struct irq_data *d)
void __iomem *reg = mtk_eint_get_offset(eint, d->hwirq,
eint->regs->mask_clr);
eint->cur_mask[d->hwirq >> 5] |= mask;
writel(mask, reg);
if (eint->dual_edge[d->hwirq])
@ -217,19 +221,6 @@ static void mtk_eint_chip_write_mask(const struct mtk_eint *eint,
}
}
static void mtk_eint_chip_read_mask(const struct mtk_eint *eint,
void __iomem *base, u32 *buf)
{
int port;
void __iomem *reg;
for (port = 0; port < eint->hw->ports; port++) {
reg = base + eint->regs->mask + (port << 2);
buf[port] = ~readl_relaxed(reg);
/* Mask is 0 when irq is enabled, and 1 when disabled. */
}
}
static int mtk_eint_irq_request_resources(struct irq_data *d)
{
struct mtk_eint *eint = irq_data_get_irq_chip_data(d);
@ -384,7 +375,6 @@ static void mtk_eint_irq_handler(struct irq_desc *desc)
int mtk_eint_do_suspend(struct mtk_eint *eint)
{
mtk_eint_chip_read_mask(eint, eint->base, eint->cur_mask);
mtk_eint_chip_write_mask(eint, eint->base, eint->wake_mask);
return 0;