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 <[email protected]>
Acked-by: Sean Wang <[email protected]>
---
Applies on top of linux-pinctrl.git/fixes.
Changes from v2:
- Added Fixes tag
- Reworded the commit message, added an example. Sean: I hope
that's what you had in mind, I can reword further, if needed.
Note that IRQCHIP_MASK_ON_SUSPEND does not work here, as it does
not handle lines that are enabled as a wake source, but without
interrupt enabled (e.g. cros_ec driver does that), which we do want
to support.
Also, Stephen Boyd suggested refactoring the genirq layer to make
it aware of such IRQ controllers. I may try to look at this in the
future, but don't have the cycles right now ,-(
drivers/pinctrl/mediatek/mtk-eint.c | 18 ++++--------------
1 file changed, 4 insertions(+), 14 deletions(-)
diff --git a/drivers/pinctrl/mediatek/mtk-eint.c b/drivers/pinctrl/mediatek/mtk-eint.c
index 737385e86beb807..7e526bcf5e0b55c 100644
--- a/drivers/pinctrl/mediatek/mtk-eint.c
+++ b/drivers/pinctrl/mediatek/mtk-eint.c
@@ -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;
--
2.22.0.410.gd8fdbe21b5-goog
On Wed, Jun 26, 2019 at 4:54 AM Nicolas Boichat <[email protected]> wrote:
> 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 <[email protected]>
> Acked-by: Sean Wang <[email protected]>
Patch applied after extending the has for Fixes: to 12 digits.
Yours,
Linus Walleij