[PATCH 1/1][SRU][K][L][M][OEM-6.1] net: wwan: t7xx: Ensure init is completed before system sleep

[AceLan Kao]

From: Kai-Heng Feng <kai.heng.feng at canonical.com>

BugLink: https://launchpad.net/bugs/2020743

When the system attempts to sleep while mtk_t7xx is not ready, the driver
cannot put the device to sleep:
[   12.472918] mtk_t7xx 0000:57:00.0: [PM] Exiting suspend, modem in invalid state
[   12.472936] mtk_t7xx 0000:57:00.0: PM: pci_pm_suspend(): t7xx_pci_pm_suspend+0x0/0x20 [mtk_t7xx] returns -14
[   12.473678] mtk_t7xx 0000:57:00.0: PM: dpm_run_callback(): pci_pm_suspend+0x0/0x1b0 returns -14
[   12.473711] mtk_t7xx 0000:57:00.0: PM: failed to suspend async: error -14
[   12.764776] PM: Some devices failed to suspend, or early wake event detected

Mediatek confirmed the device can take a rather long time to complete
its initialization, so wait for up to 20 seconds until init is done.

Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry picked from commit ab87603b251134441a67385ecc9d3371be17b7a7)
Signed-off-by: Chia-Lin Kao (AceLan) <acelan.kao at canonical.com>
---
 drivers/net/wwan/t7xx/t7xx_pci.c | 18 ++++++++++++++++++
 drivers/net/wwan/t7xx/t7xx_pci.h |  1 +
 2 files changed, 19 insertions(+)

diff --git a/drivers/net/wwan/t7xx/t7xx_pci.c b/drivers/net/wwan/t7xx/t7xx_pci.c
index 2a6fd7b8d80d..80743e064402 100644
--- a/drivers/net/wwan/t7xx/t7xx_pci.c
+++ b/drivers/net/wwan/t7xx/t7xx_pci.c
@@ -47,6 +47,7 @@
 #define T7XX_PCI_IREG_BASE		0
 #define T7XX_PCI_EREG_BASE		2
 
+#define T7XX_INIT_TIMEOUT		20
 #define PM_SLEEP_DIS_TIMEOUT_MS		20
 #define PM_ACK_TIMEOUT_MS		1500
 #define PM_AUTOSUSPEND_MS		20000
@@ -98,6 +99,7 @@ static int t7xx_pci_pm_init(struct t7xx_pci_dev *t7xx_dev)
 	spin_lock_init(&t7xx_dev->md_pm_lock);
 	init_completion(&t7xx_dev->sleep_lock_acquire);
 	init_completion(&t7xx_dev->pm_sr_ack);
+	init_completion(&t7xx_dev->init_done);
 	atomic_set(&t7xx_dev->md_pm_state, MTK_PM_INIT);
 
 	device_init_wakeup(&pdev->dev, true);
@@ -126,6 +128,7 @@ void t7xx_pci_pm_init_late(struct t7xx_pci_dev *t7xx_dev)
 	pm_runtime_mark_last_busy(&t7xx_dev->pdev->dev);
 	pm_runtime_allow(&t7xx_dev->pdev->dev);
 	pm_runtime_put_noidle(&t7xx_dev->pdev->dev);
+	complete_all(&t7xx_dev->init_done);
 }
 
 static int t7xx_pci_pm_reinit(struct t7xx_pci_dev *t7xx_dev)
@@ -531,6 +534,20 @@ static void t7xx_pci_shutdown(struct pci_dev *pdev)
 	__t7xx_pci_pm_suspend(pdev);
 }
 
+static int t7xx_pci_pm_prepare(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct t7xx_pci_dev *t7xx_dev;
+
+	t7xx_dev = pci_get_drvdata(pdev);
+	if (!wait_for_completion_timeout(&t7xx_dev->init_done, T7XX_INIT_TIMEOUT * HZ)) {
+		dev_warn(dev, "Not ready for system sleep.\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
 static int t7xx_pci_pm_suspend(struct device *dev)
 {
 	return __t7xx_pci_pm_suspend(to_pci_dev(dev));
@@ -557,6 +574,7 @@ static int t7xx_pci_pm_runtime_resume(struct device *dev)
 }
 
 static const struct dev_pm_ops t7xx_pci_pm_ops = {
+	.prepare = t7xx_pci_pm_prepare,
 	.suspend = t7xx_pci_pm_suspend,
 	.resume = t7xx_pci_pm_resume,
 	.resume_noirq = t7xx_pci_pm_resume_noirq,
diff --git a/drivers/net/wwan/t7xx/t7xx_pci.h b/drivers/net/wwan/t7xx/t7xx_pci.h
index 44a8a5034696..067bc8fc0b9e 100644
--- a/drivers/net/wwan/t7xx/t7xx_pci.h
+++ b/drivers/net/wwan/t7xx/t7xx_pci.h
@@ -70,6 +70,7 @@ struct t7xx_pci_dev {
 	struct t7xx_modem	*md;
 	struct t7xx_ccmni_ctrl	*ccmni_ctlb;
 	bool			rgu_pci_irq_en;
+	struct completion	init_done;
 
 	/* Low Power Items */
 	struct list_head	md_pm_entities;
-- 
2.34.1