From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C65D2D2F33E for ; Tue, 13 Jan 2026 16:32:03 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8DD4610E357; Tue, 13 Jan 2026 16:32:03 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="WLIdmx7H"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.17]) by gabe.freedesktop.org (Postfix) with ESMTPS id CBFF110E357 for ; Tue, 13 Jan 2026 16:32:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1768321923; x=1799857923; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=2ynAKcq4Vs/lBCn3G+wxF3Ly8bhHvu6+th+M/NpcBqw=; b=WLIdmx7HLFGwVWDQK8sXFDjIiorahrgeAVdoHePLo+d17n2XxyV6ziHy 0CaKU+RUaph5r+W4WwWaAM0/6o9w53ELYFgTQHMTiBOrz7629E1wIJTm+ 8A3dgh9Cml9A2cUFoiebiPa6GdGWDSV687JNimw5LUm08Cvu/rpexbqvh iQgprInDn8PRstJmVzidUctuYSgoCgIpgnyqx49PfFm6C6e4Lw4XW9p/E 5qgZKWV1Bu+o4Qn+zswAAXxh2LZwDInY7gFeCnuovpUT2wUiYt4plAKxJ 6pHPm4FFeCgQigXbvXhhg0CxKNNGrTZgqAN4bW8QKOB/LgqFPP9TJFe8P w==; X-CSE-ConnectionGUID: sWF7StZeQWSVQcZ1poXf6w== X-CSE-MsgGUID: WhHtj6Q6SZqoXPhPGv12YQ== X-IronPort-AV: E=McAfee;i="6800,10657,11670"; a="69520993" X-IronPort-AV: E=Sophos;i="6.21,222,1763452800"; d="scan'208";a="69520993" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by fmvoesa111.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Jan 2026 08:32:02 -0800 X-CSE-ConnectionGUID: 8BdwML9LSnCBscQPtVXkGw== X-CSE-MsgGUID: nHp2r3+LQuKTKqXr0Z4IfQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,222,1763452800"; d="scan'208";a="204060108" Received: from bnilawar-desk2.iind.intel.com ([10.190.239.41]) by fmviesa007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Jan 2026 08:31:58 -0800 From: Badal Nilawar To: intel-xe@lists.freedesktop.org, linux-acpi@vger.kernel.org, linux-pci@vger.kernel.org Cc: anshuman.gupta@intel.com, rafael@kernel.org, lenb@kernel.org, bhelgaas@google.com, ilpo.jarvinen@linux.intel.com, rodrigo.vivi@intel.com, varun.gupta@intel.com, ville.syrjala@linux.intel.com, uma.shankar@intel.com, karthik.poosa@intel.com, matthew.auld@intel.com, sk.anirban@intel.com, raag.jadav@intel.com Subject: [PATCH v6 01/12] PCI/ACPI: Add D3cold Aux Power Limit_DSM method Date: Tue, 13 Jan 2026 22:12:02 +0530 Message-ID: <20260113164200.1151788-15-badal.nilawar@intel.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260113164200.1151788-14-badal.nilawar@intel.com> References: <20260113164200.1151788-14-badal.nilawar@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" From: Anshuman Gupta Implement _DSM method 0Ah, as per PCI Firmware r3.3, sec 4.6.10, to request auxiliary power required by the device when in D3cold state. Implementation allows only a single device below the Downstream Port to request for Aux Power Limit under a given Root Port/Downstream Port because it does not track and aggregate requests from all child devices below the Downstream Port as required by PCI Firmware r3.3, sec 4.6.10. Co-developed-by: Badal Nilawar Signed-off-by: Badal Nilawar Signed-off-by: Anshuman Gupta --- V2(Bjorn/Rafael): - Call acpi_dsm_check() to find method 0Ah supported - Return retry interval to caller V3(Kuppuswamy) - Add NULL check for retry interval V4 - Define enums for aux power request status (Rafael) - Add Co-developed-by and clean up Signed-off-by (Kappuswamy) (Bjorn) - Instead of root pci device pass the pci device of driver, traverse up the tree and discover _DSM - Allow only function 0 of device to request aux power - Allow retry_interval to be NULL - Refine commit message and function description V5(Rafael) - Remove function 0 check and allow first caller of the given downstream port (with _DSM) to requst aux power including different function - Squash Patch v5.02 to this patch - In the logic, to allow single device to req power, use linked list instead of adding extra variables to acpi device structure - return positive code for no main power removal to distinguish from aux power request granted --- drivers/pci/pci-acpi.c | 136 +++++++++++++++++++++++++++++++++++++++ include/linux/pci-acpi.h | 9 +++ 2 files changed, 145 insertions(+) diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c index 9369377725fa..645d3005ba50 100644 --- a/drivers/pci/pci-acpi.c +++ b/drivers/pci/pci-acpi.c @@ -1418,6 +1418,142 @@ static void pci_acpi_optimize_delay(struct pci_dev *pdev, ACPI_FREE(obj); } +static LIST_HEAD(acpi_aux_pwr_list); +static DEFINE_MUTEX(acpi_aux_pwr_lock); + +struct aux_pwr { + u32 aux_pwr_limit; /* aux power limit granted by platform firmware */ + struct device *dev; /* device to which aux power is granted */ + struct acpi_device *adev; /* root port/downstream port */ + struct list_head list; +}; + +enum aux_pwr_req_status { + AUX_PWR_REQ_DENIED = 0x0, + AUX_PWR_REQ_GRANTED = 0x1, + AUX_PWR_REQ_NO_MAIN_PWR_REMOVAL = 0x2, + AUX_PWR_REQ_RETRY_INTERVAL_MIN = 0x11, + AUX_PWR_REQ_RETRY_INTERVAL_MAX = 0x1F +}; + +/** + * pci_acpi_request_d3cold_aux_power - Request aux power while device is in D3cold + * @dev: PCI device instance + * @requested_mw: Requested auxiliary power in milliwatts + * @retry_interval: Retry interval returned by platform to retry auxiliary + * power request + * + * Request auxilary power to platform firmware, via Root Port/Switch Downstream + * Port ACPI _DSM Function 0Ah, needed for the PCI device when it is in D3cold. + * Evaluate the _DSM and handle the response accordingly. + * + * For Multi-Function Devices, driver for Function 0 is required to report an + * aggregate power requirement covering all functions contained within the + * device. + * + * Return: 0 Aux power request granted + * 1 No main power removal + * errno on failure. + */ +int pci_acpi_request_d3cold_aux_power(struct pci_dev *dev, u32 requested_mw, + u32 *retry_interval) +{ + union acpi_object in_obj = { + .integer.type = ACPI_TYPE_INTEGER, + .integer.value = requested_mw, + }; + + union acpi_object *out_obj; + int result; + struct pci_dev *bdev; + struct acpi_device *adev; + acpi_handle handle; + struct aux_pwr *apwr, *next; + + if (!dev) + return -EINVAL; + + for (bdev = dev; bdev; bdev = pci_upstream_bridge(bdev)) { + handle = ACPI_HANDLE(&bdev->dev); + if (handle && + acpi_check_dsm(handle, &pci_acpi_dsm_guid, 4, + 1 << DSM_PCI_D3COLD_AUX_POWER_LIMIT)) + break; + } + + if (!bdev) + return -ENODEV; + + adev = ACPI_COMPANION(&bdev->dev); + if (!adev) + return -EINVAL; + + guard(mutex)(&acpi_aux_pwr_lock); + /* Check if aux power already granted to different device */ + list_for_each_entry_safe(apwr, next, &acpi_aux_pwr_list, list) { + if (apwr->adev == adev && apwr->dev != &dev->dev) { + pci_info(to_pci_dev(apwr->dev), + "D3cold Aux Power request already granted: %u mW\n", + apwr->aux_pwr_limit); + return -EALREADY; + } + if (apwr->adev == adev && apwr->dev == &dev->dev) { + list_del(&apwr->list); + kfree(apwr); + break; + } + } + + out_obj = acpi_evaluate_dsm_typed(ACPI_HANDLE(&bdev->dev), + &pci_acpi_dsm_guid, 4, + DSM_PCI_D3COLD_AUX_POWER_LIMIT, + &in_obj, ACPI_TYPE_INTEGER); + if (!out_obj) + return -EINVAL; + + result = out_obj->integer.value; + ACPI_FREE(out_obj); + + if (retry_interval) + *retry_interval = 0; + + switch (result) { + case AUX_PWR_REQ_DENIED: + pci_dbg(bdev, "D3cold Aux Power %u mW request denied\n", + requested_mw); + return -EINVAL; + case AUX_PWR_REQ_GRANTED: + pci_info(bdev, "D3cold Aux Power request granted: %u mW\n", + requested_mw); + apwr = kzalloc(sizeof(*apwr), GFP_KERNEL); + if (apwr) { + apwr->aux_pwr_limit = requested_mw; + apwr->dev = &dev->dev; + apwr->adev = adev; + INIT_LIST_HEAD(&apwr->list); + list_add(&acpi_aux_pwr_list, + &apwr->list); + } + return 0; + case AUX_PWR_REQ_NO_MAIN_PWR_REMOVAL: + pci_info(bdev, "D3cold Aux Power: Main power won't be removed\n"); + return 2; + case AUX_PWR_REQ_RETRY_INTERVAL_MIN ... AUX_PWR_REQ_RETRY_INTERVAL_MAX: + pci_info(bdev, "D3cold Aux Power request needs retry, interval: %u seconds\n", + result & 0xF); + if (retry_interval) { + *retry_interval = result & 0xF; + return -EAGAIN; + } + return -EINVAL; + default: + pci_err(bdev, "D3cold Aux Power: Reserved or unsupported response: 0x%x\n", + result); + return -EINVAL; + } +} +EXPORT_SYMBOL_GPL(pci_acpi_request_d3cold_aux_power); + static void pci_acpi_set_external_facing(struct pci_dev *dev) { u8 val; diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h index 078225b514d4..ba48e7ddb360 100644 --- a/include/linux/pci-acpi.h +++ b/include/linux/pci-acpi.h @@ -121,6 +121,7 @@ extern const guid_t pci_acpi_dsm_guid; #define DSM_PCI_DEVICE_NAME 0x07 #define DSM_PCI_POWER_ON_RESET_DELAY 0x08 #define DSM_PCI_DEVICE_READINESS_DURATIONS 0x09 +#define DSM_PCI_D3COLD_AUX_POWER_LIMIT 0x0A #ifdef CONFIG_PCIE_EDR void pci_acpi_add_edr_notifier(struct pci_dev *pdev); @@ -132,10 +133,18 @@ static inline void pci_acpi_remove_edr_notifier(struct pci_dev *pdev) { } int pci_acpi_set_companion_lookup_hook(struct acpi_device *(*func)(struct pci_dev *)); void pci_acpi_clear_companion_lookup_hook(void); +int pci_acpi_request_d3cold_aux_power(struct pci_dev *dev, u32 requested_mw, + u32 *retry_interval); #else /* CONFIG_ACPI */ static inline void acpi_pci_add_bus(struct pci_bus *bus) { } static inline void acpi_pci_remove_bus(struct pci_bus *bus) { } +static inline int pci_acpi_request_d3cold_aux_power(struct pci_dev *dev, + u32 requested_mw, + u32 *retry_interval) +{ + return -EOPNOTSUPP; +} #endif /* CONFIG_ACPI */ #endif /* _PCI_ACPI_H_ */ -- 2.52.0