[PATCH v7 6/7] PCI: brcmstb: Do not turn off regulators if EP can wake up

Jim Quinlan
2021-11-03T18:52:54Z

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>
Reviewed-by: Mark Brown <broonie@kernel.org>
---
drivers/pci/controller/pcie-brcmstb.c | 43 +++++++++++++++++++++++++--
1 file changed, 41 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index aaf6a4cbeb78..9aadb0eccfff 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -307,8 +307,20 @@ 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 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;
+}
+
static int brcm_regulators_on(struct brcm_pcie *pcie)
{
struct device *dev = pcie->dev;
@@ -316,6 +328,18 @@ static int brcm_regulators_on(struct brcm_pcie *pcie)

if (!pcie->num_supplies)
return 0;
+
+ 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;
+ }
+
ret = regulator_bulk_enable(pcie->num_supplies, pcie->supplies);
if (ret)
dev_err(dev, "failed to enable EP regulators\n");
@@ -323,13 +347,28 @@ static int brcm_regulators_on(struct brcm_pcie *pcie)
return ret;
}

-static int brcm_regulators_off(struct brcm_pcie *pcie)
+static int brcm_regulators_off(struct brcm_pcie *pcie, bool force)
{
+ struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
struct device *dev = pcie->dev;
int ret;

if (!pcie->num_supplies)
return 0;
+
+ pcie->ep_wakeup_capable = false;
+
+ if (!force && bridge->bus && brcm_pcie_link_up(pcie)) {
+ /*
+ * If at least one device on this bus is enabled as a
+ * wake-up source, do not turn off regulators.
+ */
+ pci_walk_bus(bridge->bus, pci_dev_may_wakeup,
+ &pcie->ep_wakeup_capable);
+ if (pcie->ep_wakeup_capable)
+ return 0;
+ }
+
ret = regulator_bulk_disable(pcie->num_supplies, pcie->supplies);
if (ret)
dev_err(dev, "failed to disable EP regulators\n");
@@ -1241,7 +1280,7 @@ static int brcm_pcie_suspend(struct device *dev)
reset_control_rearm(pcie->rescal);
clk_disable_unprepare(pcie->clk);

- return brcm_regulators_off(pcie);
+ return brcm_regulators_off(pcie, false);
}

static int brcm_pcie_resume(struct device *dev)