On Tue, 2018-07-17 at 18:15 +0100, Lorenzo Pieralisi wrote:

[+Rafael, Kevin, Ulf]

On Mon, Jul 02, 2018 at 03:57:43PM +0800, honghui.zhang at mediatek.com wrote:

quoted

From: Honghui Zhang <redacted>

The MTCMOS of PCIe Host for MT2712 and MT7622 will be off when system
suspend, and all the internal control register will be reset after system
resume. The PCIe link should be re-established and the related control
register values should be re-set after system resume.

Signed-off-by: Honghui Zhang <redacted>
Acked-by: Ryder Lee <ryder.lee@mediatek.com>
---
 drivers/pci/controller/pcie-mediatek.c | 67 ++++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)

diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
index 86918d4..175d7b6 100644
--- a/drivers/pci/controller/pcie-mediatek.c
+++ b/drivers/pci/controller/pcie-mediatek.c

@@ -134,12 +134,14 @@ struct mtk_pcie_port;
 /**
  * struct mtk_pcie_soc - differentiate between host generations
  * @need_fix_class_id: whether this host's class ID needed to be fixed or not
+ * @pm_support: whether the host's MTCMOS will be off when suspend
  * @ops: pointer to configuration access functions
  * @startup: pointer to controller setting functions
  * @setup_irq: pointer to initialize IRQ functions
  */
 struct mtk_pcie_soc {
 	bool need_fix_class_id;
+	bool pm_support;
 	struct pci_ops *ops;
 	int (*startup)(struct mtk_pcie_port *port);
 	int (*setup_irq)(struct mtk_pcie_port *port, struct device_node *node);

@@ -1197,12 +1199,75 @@ static int mtk_pcie_probe(struct platform_device *pdev)
 	return err;
 }
 
+static int __maybe_unused mtk_pcie_suspend_noirq(struct device *dev)
+{
+	struct mtk_pcie *pcie = dev_get_drvdata(dev);
+	const struct mtk_pcie_soc *soc = pcie->soc;
+	struct mtk_pcie_port *port;
+
+	if (!soc->pm_support)
+		return 0;
+
+	if (list_empty(&pcie->ports))
+		return 0;
+
+	list_for_each_entry(port, &pcie->ports, list) {
+		clk_disable_unprepare(port->pipe_ck);
+		clk_disable_unprepare(port->obff_ck);
+		clk_disable_unprepare(port->axi_ck);
+		clk_disable_unprepare(port->aux_ck);
+		clk_disable_unprepare(port->ahb_ck);
+		clk_disable_unprepare(port->sys_ck);
+		phy_power_off(port->phy);
+		phy_exit(port->phy);
+	}
+
+	mtk_pcie_subsys_powerdown(pcie);
+
+	return 0;
+}
+
+static int __maybe_unused mtk_pcie_resume_noirq(struct device *dev)
+{
+	struct mtk_pcie *pcie = dev_get_drvdata(dev);
+	const struct mtk_pcie_soc *soc = pcie->soc;
+	struct mtk_pcie_port *port, *tmp;
+
+	if (!soc->pm_support)
+		return 0;
+
+	if (list_empty(&pcie->ports))
+		return 0;
+
+	if (dev->pm_domain) {
+		pm_runtime_enable(dev);
+		pm_runtime_get_sync(dev);
+	}

Are these runtime PM calls needed/abused here ?

Mind explaining the logic ?

There is certainly an asymmetry with the suspend callback which made me
suspicious, I am pretty certain Rafael/Kevin/Ulf can help me clarify so
that we can make progress with this patch.

Lorenzo

Hi Lorenzo, thanks for your comments.
Sorry I don't get you.
I believe that in suspend callbacks the pm_runtime_put_sync and
pm_runtime_disable should be called to gated the CMOS for this module,
while the pm_rumtime_enable and pm_rumtime_get_sync should be called in
resume callback.

That's exactly this patch doing.
But the pm_rumtime_put_sync and pm_runtime_disable functions was wrapped
in the mtk_pcie_subsys_powerdown.

I did not call mtk_pcie_subsys_powerup since it does not just wrapped
pm_rumtime related functions but also do the platform_resource_get,
devm_ioremap, and free_ck clock get which I do not needed in resume
callback.

Do you think it will be much clear if I abstract the
platform_resource_get, devm_ioremap functions from
mtk_pcie_subsys_powerup and put it to a new functions like
mtk_pcie_subsys_resource_get, and then we may call the
mtk_pcie_subsys_powerup in the resume function?

thanks

quoted

+
+	clk_prepare_enable(pcie->free_ck);
+
+	list_for_each_entry_safe(port, tmp, &pcie->ports, list)
+		mtk_pcie_enable_port(port);
+
+	/* In case of EP was removed while system suspend. */
+	if (list_empty(&pcie->ports))
+		mtk_pcie_subsys_powerdown(pcie);
+
+	return 0;
+}
+
+static const struct dev_pm_ops mtk_pcie_pm_ops = {
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(mtk_pcie_suspend_noirq,
+				      mtk_pcie_resume_noirq)
+};
+
 static const struct mtk_pcie_soc mtk_pcie_soc_v1 = {
 	.ops = &mtk_pcie_ops,
 	.startup = mtk_pcie_startup_port,
 };
 
 static const struct mtk_pcie_soc mtk_pcie_soc_mt2712 = {
+	.pm_support = true,
 	.ops = &mtk_pcie_ops_v2,
 	.startup = mtk_pcie_startup_port_v2,
 	.setup_irq = mtk_pcie_setup_irq,

@@ -1210,6 +1275,7 @@ static const struct mtk_pcie_soc mtk_pcie_soc_mt2712 = {
 
 static const struct mtk_pcie_soc mtk_pcie_soc_mt7622 = {
 	.need_fix_class_id = true,
+	.pm_support = true,
 	.ops = &mtk_pcie_ops_v2,
 	.startup = mtk_pcie_startup_port_v2,
 	.setup_irq = mtk_pcie_setup_irq,

@@ -1229,6 +1295,7 @@ static struct platform_driver mtk_pcie_driver = {
 		.name = "mtk-pcie",
 		.of_match_table = mtk_pcie_ids,
 		.suppress_bind_attrs = true,
+		.pm = &mtk_pcie_pm_ops,
 	},
 };
 builtin_platform_driver(mtk_pcie_driver);

-- 
2.6.4