Merge branch 't7xx-pm-fixes'

Kornel Dulęba says:

====================
net: wwan: t7xx: Fix Runtime PM implementation

d10b3a695ba0 ("net: wwan: t7xx: Runtime PM") introduced support for
Runtime PM for this driver, but due to a bug in the initialization logic
the usage refcount would never reach 0, leaving the feature unused.
This patchset addresses that, together with a bug found after runtime
suspend was enabled.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 47 insertions, 11 deletions

diff --git a/drivers/net/wwan/t7xx/t7xx_hif_dpmaif.c b/drivers/net/wwan/t7xx/t7xx_hif_dpmaif.c
index 7eff3531b9a539..7ff33c1d6ac75f 100644
--- a/drivers/net/wwan/t7xx/t7xx_hif_dpmaif.c
+++ b/drivers/net/wwan/t7xx/t7xx_hif_dpmaif.c
@@ -152,6 +152,15 @@ static irqreturn_t t7xx_dpmaif_isr_handler(int irq, void *data)
 	}
 
 	t7xx_pcie_mac_clear_int(dpmaif_ctrl->t7xx_dev, isr_para->pcie_int);
+
+	return IRQ_WAKE_THREAD;
+}
+
+static irqreturn_t t7xx_dpmaif_isr_thread(int irq, void *data)
+{
+	struct dpmaif_isr_para *isr_para = data;
+	struct dpmaif_ctrl *dpmaif_ctrl = isr_para->dpmaif_ctrl;
+
 	t7xx_dpmaif_irq_cb(isr_para);
 	t7xx_pcie_mac_set_int(dpmaif_ctrl->t7xx_dev, isr_para->pcie_int);
 	return IRQ_HANDLED;
@@ -188,7 +197,7 @@ static void t7xx_dpmaif_register_pcie_irq(struct dpmaif_ctrl *dpmaif_ctrl)
 		t7xx_pcie_mac_clear_int(t7xx_dev, int_type);
 
 		t7xx_dev->intr_handler[int_type] = t7xx_dpmaif_isr_handler;
-		t7xx_dev->intr_thread[int_type] = NULL;
+		t7xx_dev->intr_thread[int_type] = t7xx_dpmaif_isr_thread;
 		t7xx_dev->callback_param[int_type] = isr_para;
 
 		t7xx_pcie_mac_clear_int_status(t7xx_dev, int_type);
diff --git a/drivers/net/wwan/t7xx/t7xx_hif_dpmaif_rx.c b/drivers/net/wwan/t7xx/t7xx_hif_dpmaif_rx.c
index aa2174a1043727..f4ff2198b5ef81 100644
--- a/drivers/net/wwan/t7xx/t7xx_hif_dpmaif_rx.c
+++ b/drivers/net/wwan/t7xx/t7xx_hif_dpmaif_rx.c
@@ -840,14 +840,13 @@ int t7xx_dpmaif_napi_rx_poll(struct napi_struct *napi, const int budget)
 
 	if (!rxq->que_started) {
 		atomic_set(&rxq->rx_processing, 0);
+		pm_runtime_put_autosuspend(rxq->dpmaif_ctrl->dev);
 		dev_err(rxq->dpmaif_ctrl->dev, "Work RXQ: %d has not been started\n", rxq->index);
 		return work_done;
 	}
 
-	if (!rxq->sleep_lock_pending) {
-		pm_runtime_get_noresume(rxq->dpmaif_ctrl->dev);
+	if (!rxq->sleep_lock_pending)
 		t7xx_pci_disable_sleep(t7xx_dev);
-	}
 
 	ret = try_wait_for_completion(&t7xx_dev->sleep_lock_acquire);
 	if (!ret) {
@@ -876,22 +875,22 @@ int t7xx_dpmaif_napi_rx_poll(struct napi_struct *napi, const int budget)
 		napi_complete_done(napi, work_done);
 		t7xx_dpmaif_clr_ip_busy_sts(&rxq->dpmaif_ctrl->hw_info);
 		t7xx_dpmaif_dlq_unmask_rx_done(&rxq->dpmaif_ctrl->hw_info, rxq->index);
+		t7xx_pci_enable_sleep(rxq->dpmaif_ctrl->t7xx_dev);
+		pm_runtime_mark_last_busy(rxq->dpmaif_ctrl->dev);
+		pm_runtime_put_autosuspend(rxq->dpmaif_ctrl->dev);
+		atomic_set(&rxq->rx_processing, 0);
 	} else {
 		t7xx_dpmaif_clr_ip_busy_sts(&rxq->dpmaif_ctrl->hw_info);
 	}
 
-	t7xx_pci_enable_sleep(rxq->dpmaif_ctrl->t7xx_dev);
-	pm_runtime_mark_last_busy(rxq->dpmaif_ctrl->dev);
-	pm_runtime_put_noidle(rxq->dpmaif_ctrl->dev);
-	atomic_set(&rxq->rx_processing, 0);
-
 	return work_done;
 }
 
 void t7xx_dpmaif_irq_rx_done(struct dpmaif_ctrl *dpmaif_ctrl, const unsigned int que_mask)
 {
 	struct dpmaif_rx_queue *rxq;
-	int qno;
+	struct dpmaif_ctrl *ctrl;
+	int qno, ret;
 
 	qno = ffs(que_mask) - 1;
 	if (qno < 0 || qno > DPMAIF_RXQ_NUM - 1) {
@@ -900,6 +899,18 @@ void t7xx_dpmaif_irq_rx_done(struct dpmaif_ctrl *dpmaif_ctrl, const unsigned int
 	}
 
 	rxq = &dpmaif_ctrl->rxq[qno];
+	ctrl = rxq->dpmaif_ctrl;
+	/* We need to make sure that the modem has been resumed before
+	 * calling napi. This can't be done inside the polling function
+	 * as we could be blocked waiting for device to be resumed,
+	 * which can't be done from softirq context the poll function
+	 * is running in.
+	 */
+	ret = pm_runtime_resume_and_get(ctrl->dev);
+	if (ret < 0 && ret != -EACCES) {
+		dev_err(ctrl->dev, "Failed to resume device: %d\n", ret);
+		return;
+	}
 	napi_schedule(&rxq->napi);
 }
 
diff --git a/drivers/net/wwan/t7xx/t7xx_netdev.c b/drivers/net/wwan/t7xx/t7xx_netdev.c
index 494a28e386a380..3ef4a8a4f8fdbc 100644
--- a/drivers/net/wwan/t7xx/t7xx_netdev.c
+++ b/drivers/net/wwan/t7xx/t7xx_netdev.c
@@ -27,6 +27,7 @@
 #include <linux/list.h>
 #include <linux/netdev_features.h>
 #include <linux/netdevice.h>
+#include <linux/pm_runtime.h>
 #include <linux/skbuff.h>
 #include <linux/types.h>
 #include <linux/wwan.h>
@@ -45,12 +46,25 @@
 
 static void t7xx_ccmni_enable_napi(struct t7xx_ccmni_ctrl *ctlb)
 {
-	int i;
+	struct dpmaif_ctrl *ctrl;
+	int i, ret;
+
+	ctrl =  ctlb->hif_ctrl;
 
 	if (ctlb->is_napi_en)
 		return;
 
 	for (i = 0; i < RXQ_NUM; i++) {
+		/* The usage count has to be bumped every time before calling
+		 * napi_schedule. It will be decresed in the poll routine,
+		 * right after napi_complete_done is called.
+		 */
+		ret = pm_runtime_resume_and_get(ctrl->dev);
+		if (ret < 0) {
+			dev_err(ctrl->dev, "Failed to resume device: %d\n",
+				ret);
+			return;
+		}
 		napi_enable(ctlb->napi[i]);
 		napi_schedule(ctlb->napi[i]);
 	}
diff --git a/drivers/net/wwan/t7xx/t7xx_pci.c b/drivers/net/wwan/t7xx/t7xx_pci.c
index 871f2a27a398a3..226fc1703e90f2 100644
--- a/drivers/net/wwan/t7xx/t7xx_pci.c
+++ b/drivers/net/wwan/t7xx/t7xx_pci.c
@@ -121,6 +121,8 @@ void t7xx_pci_pm_init_late(struct t7xx_pci_dev *t7xx_dev)
 	iowrite32(T7XX_L1_BIT(0), IREG_BASE(t7xx_dev) + ENABLE_ASPM_LOWPWR);
 	atomic_set(&t7xx_dev->md_pm_state, MTK_PM_RESUMED);
 
+	pm_runtime_mark_last_busy(&t7xx_dev->pdev->dev);
+	pm_runtime_allow(&t7xx_dev->pdev->dev);
 	pm_runtime_put_noidle(&t7xx_dev->pdev->dev);
 }