From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2067238A706 for ; Tue, 23 Jun 2026 18:31:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782239495; cv=none; b=H21Jxr5ZWqNu1u4+v8VB3Id8L2B5bc2PMxx1eEslm4N+CWOjL1YE1vjqdoG18192+UWI149Y4pPl0jKsAIQZIOk0gZLFTqZYGQCEAHvHpq37OKSLdlsg0CozIyGmiHLSKccO/TBp+rBxbJKXbS+73YD8yyvuhBzN+5uGwrHlDbg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782239495; c=relaxed/simple; bh=eKNKd51FC8HGp0OLaLEfCYpREWMo7TcVL9F+NcUbK4Y=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=UThBydglCow1tzGayXguNxCO2TpXxeDWepuZVsR7LwOvI10GzR+yd6zg1npNUN+URoAVVAsjq4qjdfkUPMbD0sPksXXinwkwNt5EeLAFP0v/XGkESqlKqjZFWSXn5N/xfaFV+2W5ojxTbgymm/5yCticB/kngTc8rTrekwntBwE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=KdTKfR6w; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="KdTKfR6w" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1782239493; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=QKDSm+Cv7jYP8itDATFdUmXFlOG8Uyg1YfrB42kBduA=; b=KdTKfR6wTmBfSUdwX5YMDCW54TJPKot72PbWn8oiqz0JvY65jeS8E3AYIPP04UbpfTpAMI jJVHK1LetYzApphNU3gDH+28ms2HLjoHS61NACqPp/UrlLI/XjaBD/sl7JWp9+z9ItUCnf zoAMzXadMY/EQ+Zj3BScBLBFPXyqfVM= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-687-sf5a8ZPLMwecNmiqqlSvyA-1; Tue, 23 Jun 2026 14:31:30 -0400 X-MC-Unique: sf5a8ZPLMwecNmiqqlSvyA-1 X-Mimecast-MFC-AGG-ID: sf5a8ZPLMwecNmiqqlSvyA_1782239488 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0078F1956096; Tue, 23 Jun 2026 18:31:27 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.44.48.11]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 355B81955F71; Tue, 23 Jun 2026 18:31:21 +0000 (UTC) From: Jose Ignacio Tornos Martinez To: bhelgaas@google.com, alex@shazbot.org, mani@kernel.org Cc: jjohnson@kernel.org, linux-pci@vger.kernel.org, linux-wireless@vger.kernel.org, ath11k@lists.infradead.org, ath12k@lists.infradead.org, mhi@lists.linux.dev, linux-kernel@vger.kernel.org, Jose Ignacio Tornos Martinez Subject: [PATCH v10] Add device-specific reset for Qualcomm devices Date: Tue, 23 Jun 2026 20:31:15 +0200 Message-ID: <20260623183115.1585273-1-jtornosm@redhat.com> Precedence: bulk X-Mailing-List: linux-wireless@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Some Qualcomm PCIe devices (WCN6855/WCN7850 WiFi cards, SDX62/SDX65 modems) lack working reset methods for VFIO passthrough scenarios. These devices have no FLR capability, advertise NoSoftRst+ (blocking PM reset), and have broken bus reset. The problem manifests in VFIO passthrough scenarios: - WCN6855 (17cb:1103) and WCN7850 (17cb:1107) WiFi devices: Normal VM operation works fine, including clean shutdown/reboot. However, when the VM terminates uncleanly (crash, force-off), VFIO attempts to reset the device before it can be assigned to another VM. Without a working reset method, the device remains in an undefined state, preventing reuse. - SDX62/SDX65 (17cb:0308) 5G modems: Never successfully initialize even on first VM assignment without proper reset capability. Add device-specific reset methods using BAR-space hardware reset registers that exist in these devices: - WCN6855/WCN7850 WiFi devices use SoC global reset via BAR0 (sequence from ath11k/ath12k driver: ath11k_pci_soc_global_reset(), ath11k_pci_sw_reset(), ath11k_mhi_set_mhictrl_reset()): - Write/clear reset bit at offset 0x3008 - Wait for PCIe link recovery (up to 5 seconds) - Clear MHI controller SYSERR status at offset 0x38 - SDX62/SDX65 modem devices use MHI SoC reset via BAR0 (sequence from MHI driver: mhi_soc_reset(), mhi_pci_reset_prepare()): - Write reset request to offset 0xb0 - Wait 2 seconds for reset completion These are true hardware reset mechanisms (not power management or firmware error recovery), providing proper device reset for VFIO scenarios. Testing was performed on desktop platforms with M.2 WiFi and modem cards using M.2-to-PCIe adapters, including extensive force-reset cycling to verify stability. Signed-off-by: Jose Ignacio Tornos Martinez --- v10: - Complete redesign based on maintainer feedback (Manivannan Sadhasivam, Alex Williamson): use actual hardware reset registers from device drivers instead of D3hot power cycling v9: https://lore.kernel.org/all/20260612142638.1243895-1-jtornosm@redhat.com/ drivers/pci/quirks.c | 118 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 118 insertions(+) diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 431c021d7414..8ad3f214e520 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -4240,6 +4240,121 @@ static int reset_hinic_vf_dev(struct pci_dev *pdev, bool probe) return 0; } +#define QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET 0x3008 +#define QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET_V BIT(0) +#define QUALCOMM_WIFI_MHISTATUS 0x48 +#define QUALCOMM_WIFI_MHICTRL 0x38 +#define QUALCOMM_WIFI_MHICTRL_RESET_MASK 0x2 + +/* + * Qualcomm WiFi device-specific reset using SoC global reset via BAR0 + * registers. + */ +static int reset_qualcomm_wifi(struct pci_dev *pdev, bool probe) +{ + bool link_recovered = false; + unsigned long timeout; + void __iomem *bar; + u32 val; + u16 cmd; + + if (probe) + return 0; + + if (pdev->current_state != PCI_D0) + return -EINVAL; + + pci_read_config_word(pdev, PCI_COMMAND, &cmd); + pci_write_config_word(pdev, PCI_COMMAND, cmd | PCI_COMMAND_MEMORY); + + bar = pci_iomap(pdev, 0, 0); + if (!bar) { + pci_write_config_word(pdev, PCI_COMMAND, cmd); + return -ENODEV; + } + + val = ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET); + val |= QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET_V; + iowrite32(val, bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET); + ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET); + + msleep(10); + + val &= ~QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET_V; + iowrite32(val, bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET); + ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET); + + msleep(10); + + timeout = jiffies + msecs_to_jiffies(5000); + while (time_before(jiffies, timeout)) { + val = ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET); + if (val != 0xffffffff) { + link_recovered = true; + break; + } + msleep(20); + } + + if (!link_recovered) { + pci_err(pdev, "PCIe link failed to recover after reset\n"); + goto out_restore; + } + + /* After SOC_GLOBAL_RESET, MHISTATUS may still have SYSERR bit set + * and thus need to set MHICTRL_RESET to clear SYSERR. + */ + iowrite32(QUALCOMM_WIFI_MHICTRL_RESET_MASK, bar + QUALCOMM_WIFI_MHICTRL); + ioread32(bar + QUALCOMM_WIFI_MHICTRL); + + msleep(10); + +out_restore: + pci_iounmap(pdev, bar); + pci_write_config_word(pdev, PCI_COMMAND, cmd); + + return link_recovered ? 0 : -ETIMEDOUT; +} + +#define MHI_SOC_RESET_REQ_OFFSET 0xb0 +#define MHI_SOC_RESET_REQ BIT(0) + +/* + * Qualcomm modem device-specific reset using MHI SoC reset via BAR0 + * register. + */ +static int reset_qualcomm_modem(struct pci_dev *pdev, bool probe) +{ + void __iomem *bar; + u16 cmd; + + if (probe) + return 0; + + if (pdev->current_state != PCI_D0) + return -EINVAL; + + pci_read_config_word(pdev, PCI_COMMAND, &cmd); + pci_write_config_word(pdev, PCI_COMMAND, cmd | PCI_COMMAND_MEMORY); + + bar = pci_iomap(pdev, 0, 0); + if (!bar) { + pci_write_config_word(pdev, PCI_COMMAND, cmd); + return -ENODEV; + } + + iowrite32(MHI_SOC_RESET_REQ, bar + MHI_SOC_RESET_REQ_OFFSET); + ioread32(bar + MHI_SOC_RESET_REQ_OFFSET); + + /* Be sure device reset has been executed */ + msleep(2000); + + pci_iounmap(pdev, bar); + pci_write_config_word(pdev, PCI_COMMAND, cmd); + + return 0; +} + static const struct pci_dev_reset_methods pci_dev_reset_methods[] = { { PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82599_SFP_VF, reset_intel_82599_sfp_virtfn }, @@ -4255,6 +4370,9 @@ static const struct pci_dev_reset_methods pci_dev_reset_methods[] = { reset_chelsio_generic_dev }, { PCI_VENDOR_ID_HUAWEI, PCI_DEVICE_ID_HINIC_VF, reset_hinic_vf_dev }, + { PCI_VENDOR_ID_QCOM, 0x1103, reset_qualcomm_wifi }, /* WCN6855 WiFi */ + { PCI_VENDOR_ID_QCOM, 0x1107, reset_qualcomm_wifi }, /* WCN7850 WiFi */ + { PCI_VENDOR_ID_QCOM, 0x0308, reset_qualcomm_modem }, /* SDX62/SDX65 modems */ { 0 } }; -- 2.54.0