From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f198.google.com (mail-pf1-f198.google.com [209.85.210.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F0EA95326CB for ; Thu, 24 Sep 2026 17:35:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.198 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790271315; cv=none; b=au69DKwe7sNVBp4lh8BgMfEfsvpdldNFi8KS+jAL248hcaW+6c8PP4etu45i6raEEDDch7YIXoVL0d23VmkvUBg9UOjoI4EGmetig3G/nm1CJgz8KjViFxr3mYsrwtVvvPVZb6zXRHveajgu9e2kLeLKptJAgfVSO3enpCiBqXQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790271315; c=relaxed/simple; bh=42HZykLu1fdko6HtVS6V2zN5Rp/brQ1pPyYBjphQlKk=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=m4l4OGNo0HrtAnDHIZw0g5lbAPGRNRcQdd8LoWHoBR7XNi6kWZMXO3P5Ps7N1C6L+ToxTHqNRHJFN4BTvVqnlphJyF7CNGrh9RX9Wndi/5NKmmqX7VlWxjrR096lsMfK+9RcvLS6ImPd4hs7kP8ypj+TEMikR0iiHITeWVI2/dY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--dmatlack.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=fVY5viZv; arc=none smtp.client-ip=209.85.210.198 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--dmatlack.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="fVY5viZv" Received: by mail-pf1-f198.google.com with SMTP id d2e1a72fcca58-8696b921ac0so77687b3a.3 for ; Thu, 24 Sep 2026 10:35:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1790271313; x=1790876113; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=44zkx5wXiPoFVTiEc5KY1Ag9ipCGGabDIfpXco19T3Q=; b=fVY5viZvNJwhWXTGOvhQqZPhuMIVibY1HUZyTgTCn/bi5pQPvRCg4IVoMxhM9zo+1E sNCdQ3rQijRAvaTA/VmP0YyLaWTuY0kJA8wdXflLEWZX52nep1UnGXl4FOLauz8oDyRn 7/cPlfd2dc0tKGxyH5v3BkKt8gS7hmdTEfoxTpcQTovGja9MgA3zotyRgjK82FgEDBI7 VgDTDTI1RwwNkuLzgFmIY84I4nSEa8a9JRgZmO9zkAMAaQA0oQztosE1fu5YUK4LKejj /RKNdDSRihCB5Q3hhecW36Svm3kUsgTyD6g9UOOIl4UJK1jVQ/+eRVb/6ugC68HM0N+9 jQhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790271313; x=1790876113; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=44zkx5wXiPoFVTiEc5KY1Ag9ipCGGabDIfpXco19T3Q=; b=gtAbNO2eO1nhOkEp6MYvT/fEoknl0phkLmT6XfrMZVmvycyPkikStmJSJMeLJ7gBKE ItReQYbrObC8CyXLaF9HsgdgE31dA7Z933g4WMvZesqN1lTNDje6e23XRHxdfrLMweFV G7SWzdo1/m4AAexazvvX4Ygo6BAmaofFnW59N+UWHik9yKqeMoLKqLRznErG7YoyUUIT NnUSCCujw+ndM8ZPkPnhjuza5163MLrgrk4iIzD7xH6issdmc0P0VU5w7ZsXjSkChSWc RtUdJ5qnB3WrlXSlT1jVLgQy4kFteBeQcTDlkf4OUw1EB5Sf1rEH7YHRi00TFLJKSLYe 0KFQ== X-Gm-Message-State: AFuF++kaMfc1bsQ8bMebbYvBzy4AIZfyrnAjm7Md/UXahK57DuVBGsII Ey+6mx+qZ/KUqfX5nTsOhXIfUycVpmN8PZcBTEloJKmEhd4AGPi27w3edMERv1PMAmvQ2pboe/m iSbRgcZ52m1AFhM1iPCbw+K92DDFJweH93SDmwDvOJu30Acx9bK+Rz0pKx+ZU/NSSLlnXhuPGcq jmvpndjF5CGxheoEkKq1P0owHOm8TRR9Z0mt+EZOczz6xsBpTasT4MalY= X-Received: from pgbfq21.prod.google.com ([2002:a05:6a02:2995:b0:c88:e5cb:265]) (user=dmatlack job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:3d09:b0:3dd:a196:906f with SMTP id adf61e73a8af0-3de0e942ae3mr2935846637.57.1790271312798; Thu, 24 Sep 2026 10:35:12 -0700 (PDT) Date: Thu, 24 Sep 2026 17:34:52 +0000 In-Reply-To: <20260924173501.856380-1-dmatlack@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260924173501.856380-1-dmatlack@google.com> X-Mailer: git-send-email 2.56.0.rc1.315.gc6ed9934b7-goog Message-ID: <20260924173501.856380-7-dmatlack@google.com> Subject: [PATCH 06/15] PCI/ASPM: Save LTR state in the saved capability store From: David Matlack To: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Cc: Alex Williamson , Bjorn Helgaas , Jason Gunthorpe , Josh Hilke , Lukas Wunner , Mahesh J Salgaonkar , "Oliver O'Halloran" , Pasha Tatashin , Pratyush Yadav , Samiullah Khawaja , Vipin Sharma , David Matlack Content-Type: text/plain; charset="UTF-8" Save and restore the LTR maximum latency registers through the per-device saved capability store instead of a private pci_cap_saved_state buffer. Reserve the DWORD by its configuration space offset during device setup, and keep accessing the registers a DWORD at a time because some devices only support DWORD access to them. No functional change intended. Assisted-by: LLM Signed-off-by: David Matlack --- drivers/pci/pci.c | 12 ++++++++---- drivers/pci/pcie/aspm.c | 19 +++---------------- 2 files changed, 11 insertions(+), 20 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 9e49806c6891..e53bca1cb50f 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3580,10 +3580,14 @@ void pci_allocate_cap_save_buffers(struct pci_dev *dev) pci_err(dev, "unable to reserve PCI-X save state\n"); } - error = pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_LTR, - 2 * sizeof(u16)); - if (error) - pci_err(dev, "unable to allocate suspend buffer for LTR\n"); + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_LTR); + if (pos) { + unsigned int off = pos + PCI_LTR_MAX_SNOOP_LAT; + + error = pci_reserve_saved_cap(dev, off, sizeof(u32)); + if (error) + pci_err(dev, "unable to reserve LTR save state\n"); + } pci_allocate_vc_save_buffers(dev); } diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 02922b887ec6..16f22af98686 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -30,8 +30,6 @@ void pci_save_ltr_state(struct pci_dev *dev) { int ltr; - struct pci_cap_saved_state *save_state; - u32 *cap; if (!pci_is_pcie(dev)) return; @@ -40,31 +38,20 @@ void pci_save_ltr_state(struct pci_dev *dev) if (!ltr) return; - save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_LTR); - if (!save_state) { - pci_err(dev, "no suspend buffer for LTR; ASPM issues possible after resume\n"); - return; - } - /* Some broken devices only support dword access to LTR */ - cap = &save_state->cap.data[0]; - pci_read_config_dword(dev, ltr + PCI_LTR_MAX_SNOOP_LAT, cap); + pci_save_cap_dword(dev, ltr + PCI_LTR_MAX_SNOOP_LAT); } void pci_restore_ltr_state(struct pci_dev *dev) { - struct pci_cap_saved_state *save_state; int ltr; - u32 *cap; - save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_LTR); ltr = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_LTR); - if (!save_state || !ltr) + if (!ltr) return; /* Some broken devices only support dword access to LTR */ - cap = &save_state->cap.data[0]; - pci_write_config_dword(dev, ltr + PCI_LTR_MAX_SNOOP_LAT, *cap); + pci_restore_cap_dword(dev, ltr + PCI_LTR_MAX_SNOOP_LAT); } void pci_configure_aspm_l1ss(struct pci_dev *pdev) -- 2.56.0.rc1.315.gc6ed9934b7-goog