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Subject[PATCH 2/3] PCI: mediatek: turn off subsys power if no link up detected
Date
There is no need to keep controller power on if slots are all empty,
so a check is added to turn it off. Besides, host controllers may not
need PM domain in some SoCs, thus we add dev->pm_domain to check that.

Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
---
drivers/pci/host/pcie-mediatek.c | 40 ++++++++++++++++++++++++++++------------
1 file changed, 28 insertions(+), 12 deletions(-)

diff --git a/drivers/pci/host/pcie-mediatek.c b/drivers/pci/host/pcie-mediatek.c
index 165d82d..d256263 100644
--- a/drivers/pci/host/pcie-mediatek.c
+++ b/drivers/pci/host/pcie-mediatek.c
@@ -118,6 +118,18 @@ static inline bool mtk_pcie_link_is_up(struct mtk_pcie_port *port)
return !!(readl(port->base + PCIE_LINK_STATUS) & PCIE_PORT_LINKUP);
}

+static void mtk_pcie_subsys_powerdown(struct mtk_pcie *pcie)
+{
+ struct device *dev = pcie->dev;
+
+ clk_disable_unprepare(pcie->free_ck);
+
+ if (dev->pm_domain) {
+ pm_runtime_put_sync(dev);
+ pm_runtime_disable(dev);
+ }
+}
+
static void mtk_pcie_port_free(struct mtk_pcie_port *port)
{
struct mtk_pcie *pcie = port->pcie;
@@ -130,7 +142,6 @@ static void mtk_pcie_port_free(struct mtk_pcie_port *port)

static void mtk_pcie_put_resources(struct mtk_pcie *pcie)
{
- struct device *dev = pcie->dev;
struct mtk_pcie_port *port, *tmp;

list_for_each_entry_safe(port, tmp, &pcie->ports, list) {
@@ -139,9 +150,7 @@ static void mtk_pcie_put_resources(struct mtk_pcie *pcie)
mtk_pcie_port_free(port);
}

- clk_disable_unprepare(pcie->free_ck);
- pm_runtime_put_sync(dev);
- pm_runtime_disable(dev);
+ mtk_pcie_subsys_powerdown(pcie);
}

static void __iomem *mtk_pcie_map_bus(struct pci_bus *bus,
@@ -340,10 +349,10 @@ static int mtk_pcie_subsys_powerup(struct mtk_pcie *pcie)
return PTR_ERR(pcie->free_ck);
}

- pm_runtime_enable(dev);
- err = pm_runtime_get_sync(dev);
- if (err)
- goto err_pm;
+ if (dev->pm_domain) {
+ pm_runtime_enable(dev);
+ pm_runtime_get_sync(dev);
+ }

/* enable top level clock */
err = clk_prepare_enable(pcie->free_ck);
@@ -355,9 +364,10 @@ static int mtk_pcie_subsys_powerup(struct mtk_pcie *pcie)
return 0;

err_free_ck:
- pm_runtime_put_sync(dev);
-err_pm:
- pm_runtime_disable(dev);
+ if (dev->pm_domain) {
+ pm_runtime_put_sync(dev);
+ pm_runtime_disable(dev);
+ }

return err;
}
@@ -439,6 +449,10 @@ static int mtk_pcie_setup(struct mtk_pcie *pcie)
list_for_each_entry_safe(port, tmp, &pcie->ports, list)
mtk_pcie_enable_ports(port);

+ /* power down PCIe subsys if slots are all empty(link down) */
+ if (list_empty(&pcie->ports))
+ mtk_pcie_subsys_powerdown(pcie);
+
return 0;
}

@@ -522,7 +536,9 @@ static int mtk_pcie_probe(struct platform_device *pdev)
return 0;

put_resources:
- mtk_pcie_put_resources(pcie);
+ if (!list_empty(&pcie->ports))
+ mtk_pcie_put_resources(pcie);
+
return err;
}

--
1.9.1
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