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

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Message-ID: <20250414-vdev_next-20250411_pm_disable-v1-1-e963677636ca@quicinc.com>
Date: Mon, 14 Apr 2025 13:17:44 +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>
Subject: [PATCH] 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. Since the PCIe core framework
enables runtime PM by default for all clients, it is essential to disable
runtime PM if the device does not support Low Power Mode (LPM).

Signed-off-by: Vivek Pernamitta <quic_vpernami@...cinc.com>
---
 drivers/bus/mhi/host/pci_generic.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/bus/mhi/host/pci_generic.c b/drivers/bus/mhi/host/pci_generic.c
index 03aa887952098661a488650053a357f883d1559b..a011fd2d48c57cf9d1aec74040153267a206d797 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)
+ * @pm_disable: disables runtime PM (optional)
  */
 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 pm_disable;
 };
 
 #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,
+	.pm_disable = true,
 };
 
 static const struct mhi_channel_config mhi_qcom_sa8775p_channels[] = {
@@ -1270,6 +1273,13 @@ 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);
 
+	/* Disable Runtime PM if device doesn't support MHI M3 state */
+	if (info->pm_disable) {
+		pm_runtime_disable(&pdev->dev);
+		pm_runtime_set_suspended(&pdev->dev);
+		return 0;
+	}
+
 	/* Only allow runtime-suspend if PME capable (for wakeup) */
 	if (pci_pme_capable(pdev, PCI_D3hot)) {
 		pm_runtime_set_autosuspend_delay(&pdev->dev, 2000);

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

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