linux-kernel - [PATCH v2 3/5] bus: mhi: host: pci_generic: Remove MHI driver and ensure graceful device recovery

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250710-sriov_vdev_next-20250630-v2-3-4bd862b822e8@quicinc.com>
Date: Thu, 10 Jul 2025 14:28:34 +0530
From: Vivek.Pernamitta@...cinc.com
To: Manivannan Sadhasivam <mani@...nel.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 v2 3/5] bus: mhi: host: pci_generic: Remove MHI driver and
 ensure graceful device recovery

From: Vivek Pernamitta <quic_vpernami@...cinc.com>

When the MHI driver is removed from the host side, it is crucial to ensure
graceful recovery of the device. To achieve this, the host driver will
perform the following steps:

1. Disable SRIOV for any SRIOV-enabled devices on the Physical Function.
2. Perform a SOC_RESET on Physical Function (PF).

Disabling SRIOV ensures that all virtual functions are properly shut down,
preventing any potential issues during the reset process. Performing
SOC_RESET on each physical function guarantees that the device is fully
reset and ready for subsequent operations.

Signed-off-by: Vivek Pernamitta <quic_vpernami@...cinc.com>
---
 drivers/bus/mhi/host/pci_generic.c | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/bus/mhi/host/pci_generic.c b/drivers/bus/mhi/host/pci_generic.c
index 4bafe93b56c54e2b091786e7fcd68a36c8247b8e..2d1381006293412fbc593316e5c7f0f59ac74da8 100644
--- a/drivers/bus/mhi/host/pci_generic.c
+++ b/drivers/bus/mhi/host/pci_generic.c
@@ -45,6 +45,8 @@
  * @sideband_wake: Devices using dedicated sideband GPIO for wakeup instead
  *		   of inband wake support (such as sdx24)
  * @no_m3: M3 not supported
+ * @reset_on_driver_unbind: Set true for devices support SOC reset and
+ *				 perform it when unbinding driver
  */
 struct mhi_pci_dev_info {
 	const struct mhi_controller_config *config;
@@ -58,6 +60,7 @@ struct mhi_pci_dev_info {
 	unsigned int mru_default;
 	bool sideband_wake;
 	bool no_m3;
+	bool reset_on_driver_unbind;
 };
 
 #define MHI_CHANNEL_CONFIG_UL(ch_num, ch_name, el_count, ev_ring) \
@@ -300,6 +303,7 @@ static const struct mhi_pci_dev_info mhi_qcom_qdu100_info = {
 	.dma_data_width = 32,
 	.sideband_wake = false,
 	.no_m3 = true,
+	.reset_on_driver_unbind = true,
 };
 
 static const struct mhi_channel_config mhi_qcom_sa8775p_channels[] = {
@@ -970,6 +974,7 @@ struct mhi_pci_device {
 	struct work_struct recovery_work;
 	struct timer_list health_check_timer;
 	unsigned long status;
+	bool reset_on_driver_unbind;
 };
 
 static int mhi_pci_read_reg(struct mhi_controller *mhi_cntrl,
@@ -1270,6 +1275,11 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	mhi_cntrl->mru = info->mru_default;
 	mhi_cntrl->name = info->name;
 
+	/* Assign reset functionalities only for PF */
+	if (pdev->is_physfn)
+		mhi_pdev->reset_on_driver_unbind = info->reset_on_driver_unbind;
+
+
 	if (info->edl_trigger)
 		mhi_cntrl->edl_trigger = mhi_pci_generic_edl_trigger;
 
@@ -1336,7 +1346,7 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	return err;
 }
 
-static void mhi_pci_remove(struct pci_dev *pdev)
+static void mhi_pci_resource_deinit(struct pci_dev *pdev)
 {
 	struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev);
 	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
@@ -1352,6 +1362,20 @@ static void mhi_pci_remove(struct pci_dev *pdev)
 	/* balancing probe put_noidle */
 	if (pci_pme_capable(pdev, PCI_D3hot))
 		pm_runtime_get_noresume(&pdev->dev);
+}
+
+static void mhi_pci_remove(struct pci_dev *pdev)
+{
+	struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev);
+	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
+
+	/* Disable SRIOV */
+	pci_disable_sriov(pdev);
+	mhi_pci_resource_deinit(pdev);
+	if (mhi_pdev->reset_on_driver_unbind) {
+		dev_info(&pdev->dev, "perform SOC reset\n");
+		mhi_soc_reset(mhi_cntrl);
+	}
 
 	mhi_unregister_controller(mhi_cntrl);
 }

-- 
2.34.1