diff mbox series

[v5,5/6] PCI: brcmstb: Do not turn off regulators if EP can wake up

Message ID 20211022140714.28767-6-jim2101024@gmail.com (mailing list archive)
State New, archived
Headers show
Series PCI: brcmstb: have host-bridge turn on sub-device power | expand

Commit Message

Jim Quinlan Oct. 22, 2021, 2:06 p.m. UTC 
If any downstream device may wake up during S2/S3 suspend, we do not want
to turn off its power when suspending.

Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
---
 drivers/pci/controller/pcie-brcmstb.c | 59 +++++++++++++++++++++++----
 1 file changed, 52 insertions(+), 7 deletions(-)

Comments

Mark Brown Oct. 22, 2021, 2:39 p.m. UTC | #1 
On Fri, Oct 22, 2021 at 10:06:58AM -0400, Jim Quinlan wrote:

> +enum {
> +	TURN_OFF,		/* Turn regulators off, unless an EP is wakeup-capable */
> +	TURN_OFF_ALWAYS,	/* Turn regulators off, no exceptions */
> +	TURN_ON,		/* Turn regulators on, unless pcie->ep_wakeup_capable */
> +};
> +
> +static int brcm_set_regulators(struct brcm_pcie *pcie, int how)
> +{
> +	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);

I can't help but think this would be easier to follow as multiple
functions, there is very little code sharing between the different
paths especially the on and off paths.

>  	if (pcie->num_supplies) {
> -		(void)brcm_set_regulators(pcie, false);
> +		(void)brcm_set_regulators(pcie, TURN_OFF_ALWAYS);

I should've mentioned this on the earlier path but it's not normal Linux
style to cast return values to void and looks worrying.
Jim Quinlan Oct. 22, 2021, 3:06 p.m. UTC | #2 
On Fri, Oct 22, 2021 at 10:39 AM Mark Brown <broonie@kernel.org> wrote:
>
> On Fri, Oct 22, 2021 at 10:06:58AM -0400, Jim Quinlan wrote:
>
> > +enum {
> > +     TURN_OFF,               /* Turn regulators off, unless an EP is wakeup-capable */
> > +     TURN_OFF_ALWAYS,        /* Turn regulators off, no exceptions */
> > +     TURN_ON,                /* Turn regulators on, unless pcie->ep_wakeup_capable */
> > +};
> > +
> > +static int brcm_set_regulators(struct brcm_pcie *pcie, int how)
> > +{
> > +     struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
>
> I can't help but think this would be easier to follow as multiple
> functions, there is very little code sharing between the different
> paths especially the on and off paths.
Agree; I just wanted to make less changes to struct pci_host_bridge.  Will fix.

>
> >       if (pcie->num_supplies) {
> > -             (void)brcm_set_regulators(pcie, false);
> > +             (void)brcm_set_regulators(pcie, TURN_OFF_ALWAYS);
>
> I should've mentioned this on the earlier path but it's not normal Linux
> style to cast return values to void and looks worrying.
Got it.

Thanks,
JimQ
diff mbox series

Patch

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 35924af1c3aa..505f74bd1a51 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -192,6 +192,7 @@  static inline void brcm_pcie_bridge_sw_init_set_generic(struct brcm_pcie *pcie,
 static inline void brcm_pcie_perst_set_4908(struct brcm_pcie *pcie, u32 val);
 static inline void brcm_pcie_perst_set_7278(struct brcm_pcie *pcie, u32 val);
 static inline void brcm_pcie_perst_set_generic(struct brcm_pcie *pcie, u32 val);
+static bool brcm_pcie_link_up(struct brcm_pcie *pcie);
 
 static const char * const supplies[] = {
 	"vpcie3v3-supply",
@@ -305,22 +306,65 @@  struct brcm_pcie {
 	void			(*bridge_sw_init_set)(struct brcm_pcie *pcie, u32 val);
 	struct regulator_bulk_data supplies[ARRAY_SIZE(supplies)];
 	unsigned int		num_supplies;
+	bool			ep_wakeup_capable;
 };
 
-static int brcm_set_regulators(struct brcm_pcie *pcie, bool on)
+static int pci_dev_may_wakeup(struct pci_dev *dev, void *data)
 {
+	bool *ret = data;
+
+	if (device_may_wakeup(&dev->dev)) {
+		*ret = true;
+		dev_dbg(&dev->dev, "disable cancelled for wake-up device\n");
+	}
+	return (int) *ret;
+}
+
+enum {
+	TURN_OFF,		/* Turn regulators off, unless an EP is wakeup-capable */
+	TURN_OFF_ALWAYS,	/* Turn regulators off, no exceptions */
+	TURN_ON,		/* Turn regulators on, unless pcie->ep_wakeup_capable */
+};
+
+static int brcm_set_regulators(struct brcm_pcie *pcie, int how)
+{
+	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
 	struct device *dev = pcie->dev;
 	int ret;
 
 	if (!pcie->num_supplies)
 		return 0;
-	if (on)
+	if (how == TURN_ON) {
+		if (pcie->ep_wakeup_capable) {
+			/*
+			 * We are resuming from a suspend.  In the
+			 * previous suspend we did not disable the power
+			 * supplies, so there is no need to enable them
+			 * (and falsely increase their usage count).
+			 */
+			pcie->ep_wakeup_capable = false;
+			return 0;
+		}
+	} else if (how == TURN_OFF) {
+		/*
+		 * If at least one device on this bus is enabled as a
+		 * wake-up source, do not turn off regulators.
+		 */
+		pcie->ep_wakeup_capable = false;
+		if (bridge->bus && brcm_pcie_link_up(pcie)) {
+			pci_walk_bus(bridge->bus, pci_dev_may_wakeup, &pcie->ep_wakeup_capable);
+			if (pcie->ep_wakeup_capable)
+				return 0;
+		}
+	}
+
+	if (how == TURN_ON)
 		ret = regulator_bulk_enable(pcie->num_supplies, pcie->supplies);
 	else
 		ret = regulator_bulk_disable(pcie->num_supplies, pcie->supplies);
 	if (ret)
 		dev_err(dev, "failed to %s EP regulators\n",
-			on ? "enable" : "disable");
+			how == TURN_ON ? "enable" : "disable");
 	return ret;
 }
 
@@ -1234,7 +1278,7 @@  static int brcm_pcie_suspend(struct device *dev)
 	reset_control_rearm(pcie->rescal);
 	clk_disable_unprepare(pcie->clk);
 
-	return brcm_set_regulators(pcie, false);
+	return brcm_set_regulators(pcie, TURN_OFF);
 }
 
 static int brcm_pcie_resume(struct device *dev)
@@ -1250,7 +1294,8 @@  static int brcm_pcie_resume(struct device *dev)
 	ret = reset_control_reset(pcie->rescal);
 	if (ret)
 		goto err_disable_clk;
-	ret = brcm_set_regulators(pcie, true);
+
+	ret = brcm_set_regulators(pcie, TURN_ON);
 	if (ret)
 		goto err_reset;
 
@@ -1297,7 +1342,7 @@  static void __brcm_pcie_remove(struct brcm_pcie *pcie)
 	reset_control_rearm(pcie->rescal);
 	clk_disable_unprepare(pcie->clk);
 	if (pcie->num_supplies) {
-		(void)brcm_set_regulators(pcie, false);
+		(void)brcm_set_regulators(pcie, TURN_OFF_ALWAYS);
 		regulator_bulk_free(pcie->num_supplies, pcie->supplies);
 	}
 }
@@ -1348,7 +1393,7 @@  static int brcm_pcie_pci_subdev_prepare(bool query, struct pci_bus *bus, int dev
 		return ret;
 	}
 
-	ret = brcm_set_regulators(pcie, true);
+	ret = brcm_set_regulators(pcie, TURN_ON);
 	if (ret)
 		goto err_out0;