[PATCH v2 3/6] PCI: brcmstb: Do not turn off regulators if EP can wake up

From: Jim Quinlan
Date: Mon Nov 30 2020 - 16:13:35 EST


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 <james.quinlan@xxxxxxxxxxxx>
---
drivers/pci/controller/pcie-brcmstb.c | 58 +++++++++++++++++++++++----
1 file changed, 51 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 9d4ac42b3bee..cbdb315d4b2f 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -193,6 +193,7 @@ static inline void brcm_pcie_bridge_sw_init_set_7278(struct brcm_pcie *pcie, u32
static inline void brcm_pcie_bridge_sw_init_set_generic(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);

enum {
RGR1_SW_INIT_1,
@@ -293,14 +294,57 @@ struct brcm_pcie {
void (*perst_set)(struct brcm_pcie *pcie, u32 val);
void (*bridge_sw_init_set)(struct brcm_pcie *pcie, u32 val);
struct regulator_bulk_data supplies[ARRAY_SIZE(ep_regulator_names)];
+ bool ep_wakeup_capable;
};

-static void 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 egulators 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 void 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 (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;
+ }
+ } 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;
+ }
+ }
+
+ if (how == TURN_ON)
ret = regulator_bulk_enable(ARRAY_SIZE(ep_regulator_names),
pcie->supplies);
else
@@ -308,7 +352,7 @@ static void brcm_set_regulators(struct brcm_pcie *pcie, bool on)
pcie->supplies);
if (ret)
dev_err(dev, "failed to %s EP regulators\n",
- on ? "enable" : "disable");
+ how == TURN_ON ? "enable" : "disable");
}

/*
@@ -1161,7 +1205,7 @@ static int brcm_pcie_suspend(struct device *dev)
brcm_pcie_turn_off(pcie);
ret = brcm_phy_stop(pcie);
clk_disable_unprepare(pcie->clk);
- brcm_set_regulators(pcie, false);
+ brcm_set_regulators(pcie, TURN_OFF);

return ret;
}
@@ -1174,7 +1218,7 @@ static int brcm_pcie_resume(struct device *dev)
int ret;

base = pcie->base;
- brcm_set_regulators(pcie, true);
+ brcm_set_regulators(pcie, TURN_ON);
clk_prepare_enable(pcie->clk);

ret = brcm_phy_start(pcie);
@@ -1213,7 +1257,7 @@ static void __brcm_pcie_remove(struct brcm_pcie *pcie)
brcm_phy_stop(pcie);
reset_control_assert(pcie->rescal);
clk_disable_unprepare(pcie->clk);
- brcm_set_regulators(pcie, false);
+ brcm_set_regulators(pcie, TURN_OFF_ALWAYS);
}

static int brcm_pcie_remove(struct platform_device *pdev)
@@ -1308,7 +1352,7 @@ static int brcm_pcie_probe(struct platform_device *pdev)
return ret;
}

- brcm_set_regulators(pcie, true);
+ brcm_set_regulators(pcie, TURN_ON);
ret = brcm_pcie_setup(pcie);
if (ret)
goto fail;
--
2.17.1

Attachment: smime.p7s
Description: S/MIME Cryptographic Signature