From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752146AbdAaTqC (ORCPT ); Tue, 31 Jan 2017 14:46:02 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:33522 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751698AbdAaTpz (ORCPT ); Tue, 31 Jan 2017 14:45:55 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 17FBB6077B Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=okaya@codeaurora.org From: Sinan Kaya To: linux-pci@vger.kernel.org, timur@codeaurora.org, cov@codeaurora.org Cc: linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Sinan Kaya , linux-kernel@vger.kernel.org (open list) Subject: [PATCH V2] PCI/ASPM: reconfigure ASPM following hotplug for POLICY_DEFAULT Date: Tue, 31 Jan 2017 14:45:27 -0500 Message-Id: <1485891928-14573-1-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When the operating system is booted with the default ASPM policy (POLICY_DEFAULT), the current code is determining the ASPM policy set up by the BIOS by querying the enable/disable states from ASPM registers. In the case of hotplug removal, the ASPM registers get cleared by calling the pcie_aspm_exit_link_state() function. An insertion following hotplug removal reads incorrect policy as ASPM disabled even though ASPM was enabled during boot. Adding a flag to the struct pci_dev and saving the power up policy in the bridge to be reused during hotplug insertion. Bridge's enable counter is used as a switch to determine when to use saved value. Signed-off-by: Sinan Kaya --- drivers/pci/pcie/aspm.c | 21 +++++++++++++++++---- include/linux/pci.h | 1 + 2 files changed, 18 insertions(+), 4 deletions(-) diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 17ac1dc..5cfcc6d 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -338,8 +338,9 @@ static void pcie_aspm_check_latency(struct pci_dev *endpoint) } } -static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) +static void pcie_aspm_cap_init(struct pci_dev *pdev, int blacklist) { + struct pcie_link_state *link = pdev->link_state; struct pci_dev *child, *parent = link->pdev; struct pci_bus *linkbus = parent->subordinate; struct aspm_register_info upreg, dwreg; @@ -397,8 +398,20 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) link->latency_up.l1 = calc_l1_latency(upreg.latency_encoding_l1); link->latency_dw.l1 = calc_l1_latency(dwreg.latency_encoding_l1); - /* Save default state */ - link->aspm_default = link->aspm_enabled; + /* + * Save default state from FW when enabling ASPM for the first time + * during boot by looking at the calculated link->aspm_enabled bits + * above and enable_cnt will be zero. + * + * If this path is getting called for the second/third time + * (enable_cnt will be non-zero). Assume that the current state of the + * ASPM registers may not necessarily match what FW asked us to do as + * in the case of hotplug insertion/removal. + */ + if (!atomic_read(&pdev->enable_cnt)) + pdev->aspm_default = link->aspm_default = link->aspm_enabled; + else + link->aspm_default = pdev->aspm_default; /* Setup initial capable state. Will be updated later */ link->aspm_capable = link->aspm_support; @@ -599,7 +612,7 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev) * upstream links also because capable state of them can be * update through pcie_aspm_cap_init(). */ - pcie_aspm_cap_init(link, blacklist); + pcie_aspm_cap_init(pdev, blacklist); /* Setup initial Clock PM state */ pcie_clkpm_cap_init(link, blacklist); diff --git a/include/linux/pci.h b/include/linux/pci.h index e2d1a12..521f88c 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -321,6 +321,7 @@ struct pci_dev { #ifdef CONFIG_PCIEASPM struct pcie_link_state *link_state; /* ASPM link state */ + unsigned int aspm_default; /* ASPM policy set by BIOS */ #endif pci_channel_state_t error_state; /* current connectivity state */ -- 1.9.1