From patchwork Tue Oct 22 08:31:47 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Siddharth Vadapalli X-Patchwork-Id: 837706 Received: from lelv0142.ext.ti.com (lelv0142.ext.ti.com [198.47.23.249]) (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 E834A27735; Tue, 22 Oct 2024 08:32:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.47.23.249 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729585932; cv=none; b=hEIBx/e8C+BfNUZAvG5s4j/dh67wgaiw6JjgEwTr9wXMEO0X2SqnnLpLQtb1lOvj7ZZU+j6z5J4GsStShdIBvLw5zBykItkKEe7fo8FdtLmMv7m0EPkR1kvFGQK5/CnXi2fstsKryFo7oonrW9CPwEx0Z1awkRhH31J921KXoCc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729585932; c=relaxed/simple; bh=24FHTTIKlshgcnqTCzujRu8x5PDDvQ70ZtdJSrLkunU=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=XyicZ4xnwhOYq73gV/eiAuhLMnK4UVS1fMy6VnJ1DifYw05PXXer+4v0ThimZiuK5pcjotGMgjHQntjw19QXN6yYALPcIwunZe2xDVtuh0148eESmdPm2mADz2iaKDp9EIOxPX8WmyqBdNXxjSsEUDuogRwQSNFe2BQklOVPTpE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=ti.com; spf=pass smtp.mailfrom=ti.com; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b=isz6k2P0; arc=none smtp.client-ip=198.47.23.249 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=ti.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ti.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="isz6k2P0" Received: from lelv0266.itg.ti.com ([10.180.67.225]) by lelv0142.ext.ti.com (8.15.2/8.15.2) with ESMTP id 49M8VqwT103269; Tue, 22 Oct 2024 03:31:52 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1729585912; bh=YAMUtebJLSB7p1vdKcR9hmMWoyxoGZwJK0XkcbmsWm8=; h=From:To:CC:Subject:Date; b=isz6k2P0v8fKnPaNqF5TebLSNayOh1js0lHQ4hRVh8cqllDL6AX/fVn2DeM1ZeNU6 SmF9yj7+a0QpNrOCHstvwgotebSqWao97gqGpKBuGy2LfYxehfLpdwbI/9IEw2GkJB fAlb/p+RgaEYEiAG3yQbU5uQ23dYNZ8qkT+my4RM= Received: from DLEE115.ent.ti.com (dlee115.ent.ti.com [157.170.170.26]) by lelv0266.itg.ti.com (8.15.2/8.15.2) with ESMTP id 49M8Vq1S033237; Tue, 22 Oct 2024 03:31:52 -0500 Received: from DLEE105.ent.ti.com (157.170.170.35) by DLEE115.ent.ti.com (157.170.170.26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.23; Tue, 22 Oct 2024 03:31:52 -0500 Received: from lelvsmtp6.itg.ti.com (10.180.75.249) by DLEE105.ent.ti.com (157.170.170.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.23 via Frontend Transport; Tue, 22 Oct 2024 03:31:52 -0500 Received: from uda0492258.dhcp.ti.com (uda0492258.dhcp.ti.com [10.24.72.81]) by lelvsmtp6.itg.ti.com (8.15.2/8.15.2) with ESMTP id 49M8Vm4B052525; Tue, 22 Oct 2024 03:31:49 -0500 From: Siddharth Vadapalli To: , , , , , , CC: , , , , , Subject: [PATCH] PCI: j721e: Deassert PERST# after a delay of PCIE_T_PVPERL_MS ms Date: Tue, 22 Oct 2024 14:01:47 +0530 Message-ID: <20241022083147.2773123-1-s-vadapalli@ti.com> X-Mailer: git-send-email 2.40.1 Precedence: bulk X-Mailing-List: linux-omap@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-C2ProcessedOrg: 333ef613-75bf-4e12-a4b1-8e3623f5dcea According to Section 2.2 of the PCI Express Card Electromechanical Specification (Revision 5.1), in order to ensure that the power and the reference clock are stable, PERST# has to be deasserted after a delay of 100 milliseconds (TPVPERL). Currently, it is being assumed that the power is already stable, which is not necessarily true. Hence, change the delay to PCIE_T_PVPERL_MS to guarantee that power and reference clock are stable. Fixes: f96b69713733 ("PCI: j721e: Use T_PERST_CLK_US macro") Signed-off-by: Siddharth Vadapalli --- Hello, This patch is based on commit c2ee9f594da8 KVM: selftests: Fix build on on non-x86 architectures of Mainline Linux. Regards, Siddharth. drivers/pci/controller/cadence/pci-j721e.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/drivers/pci/controller/cadence/pci-j721e.c b/drivers/pci/controller/cadence/pci-j721e.c index 284f2e0e4d26..e464cfc2c332 100644 --- a/drivers/pci/controller/cadence/pci-j721e.c +++ b/drivers/pci/controller/cadence/pci-j721e.c @@ -671,15 +671,14 @@ static int j721e_pcie_resume_noirq(struct device *dev) return ret; /* - * The "Power Sequencing and Reset Signal Timings" table of the - * PCI Express Card Electromechanical Specification, Revision - * 5.1, Section 2.9.2, Symbol "T_PERST-CLK", indicates PERST# - * should be deasserted after minimum of 100us once REFCLK is - * stable. The REFCLK to the connector in RC mode is selected - * while enabling the PHY. So deassert PERST# after 100 us. + * Section 2.2 of the PCI Express Card Electromechanical + * Specification (Revision 5.1) mandates that the deassertion + * of the PERST# signal should be delayed by 100 ms (TPVPERL). + * This shall ensure that the power and the reference clock + * are stable. */ if (pcie->reset_gpio) { - fsleep(PCIE_T_PERST_CLK_US); + msleep(PCIE_T_PVPERL_MS); gpiod_set_value_cansleep(pcie->reset_gpio, 1); }