[PATCH AUTOSEL 4.19 16/26] pinctrl: mcp23s08: Fix add_data and irqchip_add_nested call order

[PATCH AUTOSEL 4.19 16/26] pinctrl: mcp23s08: Fix add_data and irqchip_add_nested call order

[Sasha Levin]

From: Phil Reid <preid@electromag.com.au>

[ Upstream commit 6dbc6e6f58556369bf999cd7d9793586f1b0e4b4 ]

Currently probing of the mcp23s08 results in an error message
"detected irqchip that is shared with multiple gpiochips:
please fix the driver"

This is due to the following:

Call to mcp23s08_irqchip_setup() with call hierarchy:
mcp23s08_irqchip_setup()
  gpiochip_irqchip_add_nested()
    gpiochip_irqchip_add_key()
      gpiochip_set_irq_hooks()

Call to devm_gpiochip_add_data() with call hierarchy:
devm_gpiochip_add_data()
  gpiochip_add_data_with_key()
    gpiochip_add_irqchip()
      gpiochip_set_irq_hooks()

The gpiochip_add_irqchip() returns immediately if there isn't a irqchip
but we added a irqchip due to the previous mcp23s08_irqchip_setup()
call. So it calls gpiochip_set_irq_hooks() a second time.

Fix this by moving the call to devm_gpiochip_add_data before
the call to mcp23s08_irqchip_setup

Fixes: 02e389e63e35 ("pinctrl: mcp23s08: fix irq setup order")
Suggested-by: Marco Felsch <m.felsch@pengutronix.de>
Signed-off-by: Phil Reid <preid@electromag.com.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/pinctrl/pinctrl-mcp23s08.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/pinctrl/pinctrl-mcp23s08.c b/drivers/pinctrl/pinctrl-mcp23s08.c
index cecbce21d01f..33c3eca0ece9 100644
--- a/drivers/pinctrl/pinctrl-mcp23s08.c
+++ b/drivers/pinctrl/pinctrl-mcp23s08.c
@@ -889,6 +889,10 @@ static int mcp23s08_probe_one(struct mcp23s08 *mcp, struct device *dev,
 	if (ret < 0)
 		goto fail;
 
+	ret = devm_gpiochip_add_data(dev, &mcp->chip, mcp);
+	if (ret < 0)
+		goto fail;
+
 	mcp->irq_controller =
 		device_property_read_bool(dev, "interrupt-controller");
 	if (mcp->irq && mcp->irq_controller) {
@@ -930,10 +934,6 @@ static int mcp23s08_probe_one(struct mcp23s08 *mcp, struct device *dev,
 			goto fail;
 	}
 
-	ret = devm_gpiochip_add_data(dev, &mcp->chip, mcp);
-	if (ret < 0)
-		goto fail;
-
 	if (one_regmap_config) {
 		mcp->pinctrl_desc.name = devm_kasprintf(dev, GFP_KERNEL,
 				"mcp23xxx-pinctrl.%d", raw_chip_address);
-- 
2.20.1

[PATCH AUTOSEL 4.19 23/26] pinctrl: mediatek: Ignore interrupts that are wake only during resume

[Sasha Levin]

From: Nicolas Boichat <drinkcat@chromium.org>

[ Upstream commit 35594bc7cecf3a78504b590e350570e8f4d7779e ]

Before suspending, mtk-eint would set the interrupt mask to the
one in wake_mask. However, some of these interrupts may not have a
corresponding interrupt handler, or the interrupt may be disabled.

On resume, the eint irq handler would trigger nevertheless,
and irq/pm.c:irq_pm_check_wakeup would be called, which would
try to call irq_disable. However, if the interrupt is not enabled
(irqd_irq_disabled(&desc->irq_data) is true), the call does nothing,
and the interrupt is left enabled in the eint driver.

Especially for level-sensitive interrupts, this will lead to an
interrupt storm on resume.

If we detect that an interrupt is only in wake_mask, but not in
cur_mask, we can just mask it out immediately (as mtk_eint_resume
would do anyway at a later stage in the resume sequence, when
restoring cur_mask).

Fixes: bf22ff45bed6 ("genirq: Avoid unnecessary low level irq function calls")
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/pinctrl/mediatek/mtk-eint.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/pinctrl/mediatek/mtk-eint.c b/drivers/pinctrl/mediatek/mtk-eint.c
index a613e546717a..b9f3c02ba59d 100644
--- a/drivers/pinctrl/mediatek/mtk-eint.c
+++ b/drivers/pinctrl/mediatek/mtk-eint.c
@@ -318,7 +318,7 @@ static void mtk_eint_irq_handler(struct irq_desc *desc)
 	struct irq_chip *chip = irq_desc_get_chip(desc);
 	struct mtk_eint *eint = irq_desc_get_handler_data(desc);
 	unsigned int status, eint_num;
-	int offset, index, virq;
+	int offset, mask_offset, index, virq;
 	void __iomem *reg =  mtk_eint_get_offset(eint, 0, eint->regs->stat);
 	int dual_edge, start_level, curr_level;
 
@@ -328,10 +328,24 @@ static void mtk_eint_irq_handler(struct irq_desc *desc)
 		status = readl(reg);
 		while (status) {
 			offset = __ffs(status);
+			mask_offset = eint_num >> 5;
 			index = eint_num + offset;
 			virq = irq_find_mapping(eint->domain, index);
 			status &= ~BIT(offset);
 
+			/*
+			 * If we get an interrupt on pin that was only required
+			 * for wake (but no real interrupt requested), mask the
+			 * interrupt (as would mtk_eint_resume do anyway later
+			 * in the resume sequence).
+			 */
+			if (eint->wake_mask[mask_offset] & BIT(offset) &&
+			    !(eint->cur_mask[mask_offset] & BIT(offset))) {
+				writel_relaxed(BIT(offset), reg -
+					eint->regs->stat +
+					eint->regs->mask_set);
+			}
+
 			dual_edge = eint->dual_edge[index];
 			if (dual_edge) {
 				/*
-- 
2.20.1

[PATCH AUTOSEL 4.19 25/26] pinctrl: mediatek: Update cur_mask in mask/mask ops

[Sasha Levin]

From: Nicolas Boichat <drinkcat@chromium.org>

[ Upstream commit 9d957a959bc8c3dfe37572ac8e99affb5a885965 ]

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: 58a5e1b64bb0 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 b9f3c02ba59d..564cfaee129d 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;
-- 
2.20.1