linux-kernel - [PATCH v4] bus: mhi: host: pci: Disable runtime PM for QDU100

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Message-ID: <20250425-vdev_next-20250411_pm_disable-v4-1-d4870a73ebf9@quicinc.com>
Date: Fri, 25 Apr 2025 12:49:31 +0530
From: Vivek Pernamitta <quic_vpernami@...cinc.com>
To: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
CC: <mhi@...ts.linux.dev>, <linux-arm-msm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        Vivek Pernamitta <quic_vpernami@...cinc.com>,
        Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
Subject: [PATCH v4] bus: mhi: host: pci: Disable runtime PM for QDU100

The QDU100 device does not support the MHI M3 state, necessitating the
disabling of runtime PM for this device. It is essential to disable
runtime PM if the device does not support M3 state.

Signed-off-by: Vivek Pernamitta <quic_vpernami@...cinc.com>
Reviewed-by: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
---
Changes in v4:
- updated commit test from LPM to M3
- updated comments in code
- Link to v3: https://lore.kernel.org/r/20250418-vdev_next-20250411_pm_disable-v3-1-0175b691de61@quicinc.com

Changes in v3:
- updated variable to no_m3 from pm_disable 
- Link to v2: https://lore.kernel.org/r/20250418-vdev_next-20250411_pm_disable-v2-1-27dd8d433f3b@quicinc.com

Changes in v2:
- Updated device from getting runtime suspended by avoid skipping autosuspend.
- Updated commit message.
- Link to v1: https://lore.kernel.org/r/20250414-vdev_next-20250411_pm_disable-v1-1-e963677636ca@quicinc.com
---
 drivers/bus/mhi/host/pci_generic.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/bus/mhi/host/pci_generic.c b/drivers/bus/mhi/host/pci_generic.c
index 03aa887952098661a488650053a357f883d1559b..49910b502d7c0b912f1dfba2c1ed6daa7b5583ef 100644
--- a/drivers/bus/mhi/host/pci_generic.c
+++ b/drivers/bus/mhi/host/pci_generic.c
@@ -43,6 +43,7 @@
  * @mru_default: default MRU size for MBIM network packets
  * @sideband_wake: Devices using dedicated sideband GPIO for wakeup instead
  *		   of inband wake support (such as sdx24)
+ * @no_m3: M3 is disabled
  */
 struct mhi_pci_dev_info {
 	const struct mhi_controller_config *config;
@@ -54,6 +55,7 @@ struct mhi_pci_dev_info {
 	unsigned int dma_data_width;
 	unsigned int mru_default;
 	bool sideband_wake;
+	bool no_m3;
 };
 
 #define MHI_CHANNEL_CONFIG_UL(ch_num, ch_name, el_count, ev_ring) \
@@ -295,6 +297,7 @@ static const struct mhi_pci_dev_info mhi_qcom_qdu100_info = {
 	.bar_num = MHI_PCI_DEFAULT_BAR_NUM,
 	.dma_data_width = 32,
 	.sideband_wake = false,
+	.no_m3 = true,
 };
 
 static const struct mhi_channel_config mhi_qcom_sa8775p_channels[] = {
@@ -1270,8 +1273,8 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	/* start health check */
 	mod_timer(&mhi_pdev->health_check_timer, jiffies + HEALTH_CHECK_PERIOD);
 
-	/* Only allow runtime-suspend if PME capable (for wakeup) */
-	if (pci_pme_capable(pdev, PCI_D3hot)) {
+	/* Allow runtime suspend only if both PME from D3Hot and M3 are supported */
+	if (pci_pme_capable(pdev, PCI_D3hot) && !(info->no_m3)) {
 		pm_runtime_set_autosuspend_delay(&pdev->dev, 2000);
 		pm_runtime_use_autosuspend(&pdev->dev);
 		pm_runtime_mark_last_busy(&pdev->dev);

---
base-commit: 01c6df60d5d4ae00cd5c1648818744838bba7763
change-id: 20250414-vdev_next-20250411_pm_disable-53d5e1acd45e

Best regards,
-- 
Vivek Pernamitta <quic_vpernami@...cinc.com>