From patchwork Thu Aug 17 09:36:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Achal Verma X-Patchwork-Id: 13356206 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 24CB2C27C7A for ; Thu, 17 Aug 2023 09:37:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:Subject:CC :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=07xKhdBtWMj8umea0dJ5gWbERjkSzSbaJj2RA8XBiRI=; b=CrlEajJSpTSUR1 yF2HGua/zWwO3PpQ7uNu5jCRO0gRL+61J0/uMtFFUz3h5jH3qelLVKBGTO3UN85Gy3vjzgp+xxIIA 4yMFHA4MuVM7g4XadxWWfZk80yx8BVPAgGP2RiuOG/2+e6fzijDde2jOqlOjdTymuaiO5U9PMeVzK B43kNyi+IaYzFt3z+JTSVF5p9wyIUNeIHENrjcefboMnDnzVD+bpXnKdYSUweQXdjg2ER7PtApxSA ihIUFNWJN1bPGVYyd00ZuhkhgYCfkAGBPpdERHBoXM4wII3GTILbeueB6ljA5/k2ZcpJ8VAVWysZT 1azvEWaTC+hJO/gCUYkQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qWZQh-005x63-2i; Thu, 17 Aug 2023 09:36:35 +0000 Received: from fllv0015.ext.ti.com ([198.47.19.141]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qWZQf-005x5Y-1h for linux-arm-kernel@lists.infradead.org; Thu, 17 Aug 2023 09:36:35 +0000 Received: from lelv0266.itg.ti.com ([10.180.67.225]) by fllv0015.ext.ti.com (8.15.2/8.15.2) with ESMTP id 37H9aMbv130389; Thu, 17 Aug 2023 04:36:22 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1692264982; bh=cM2v5idW6LPns03CXo999YFb/jfLx+ptnb6APGeD3xc=; h=From:To:CC:Subject:Date; b=JCpoUKTSRGM3I9svuYGs0nI+tSY9C83ZPgI4YIT+b4Mls6wBNs55eiR7Dg93VZB2C YN8M0nrmEAOY8U7lQyCWcHLkfTBPTx6uQEUCEr83L/Fhp7hbUgfHXV4DcoGSuFMMde HasRk0xKB45E/33Mi0GYhPDzeRcb0lamgZEgjH0s= Received: from DFLE114.ent.ti.com (dfle114.ent.ti.com [10.64.6.35]) by lelv0266.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 37H9aM5T048780 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 17 Aug 2023 04:36:22 -0500 Received: from DFLE109.ent.ti.com (10.64.6.30) by DFLE114.ent.ti.com (10.64.6.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.23; Thu, 17 Aug 2023 04:36:21 -0500 Received: from lelv0326.itg.ti.com (10.180.67.84) by DFLE109.ent.ti.com (10.64.6.30) 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; Thu, 17 Aug 2023 04:36:21 -0500 Received: from localhost (ileaxei01-snat2.itg.ti.com [10.180.69.6]) by lelv0326.itg.ti.com (8.15.2/8.15.2) with ESMTP id 37H9aK5Y007933; Thu, 17 Aug 2023 04:36:20 -0500 From: Achal Verma To: Vignesh Raghavendra , Tom Joseph , Lorenzo Pieralisi , Krzysztof Wilczy_ski , Rob Herring , Bjorn Helgaas CC: , , , , Achal Verma Subject: [PATCH v5] PCI: j721e: Delay T_PVPERL+TPERST_CLK before PERST# inactive Date: Thu, 17 Aug 2023 15:06:19 +0530 Message-ID: <20230817093619.1079267-1-a-verma1@ti.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230817_023633_663207_AB95F0A3 X-CRM114-Status: GOOD ( 14.69 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org As per the PCIe Card Electromechanical specification REV. 5.0, PERST# signal should be de-asserted after minimum 100ms from the time power-rails achieve specified operating limits and 100us after reference clock gets stable. From PCIe Card Electromechanical specification REV. 5.0 section 2.9.2: TPVPERL: Power stable to PERST# inactive - 100ms TPERST_CLK: REFCLK stable before PERST# inactive - 100us Fixes: f3e25911a430 ("PCI: j721e: Add TI J721E PCIe driver") Signed-off-by: Achal Verma --- drivers/pci/controller/cadence/pci-j721e.c | 30 +++++++++++----------- drivers/pci/pci.h | 3 +++ 2 files changed, 18 insertions(+), 15 deletions(-) diff --git a/drivers/pci/controller/cadence/pci-j721e.c b/drivers/pci/controller/cadence/pci-j721e.c index e70213c9060a..b09924b010ab 100644 --- a/drivers/pci/controller/cadence/pci-j721e.c +++ b/drivers/pci/controller/cadence/pci-j721e.c @@ -34,6 +34,8 @@ #define J721E_PCIE_USER_LINKSTATUS 0x14 #define LINK_STATUS GENMASK(1, 0) +#define PERST_INACTIVE_US (PCIE_TPVPERL_MS*USEC_PER_MSEC + PCIE_TPERST_CLK_US) + enum link_status { NO_RECEIVERS_DETECTED, LINK_TRAINING_IN_PROGRESS, @@ -359,7 +361,7 @@ static int j721e_pcie_probe(struct platform_device *pdev) struct j721e_pcie *pcie; struct cdns_pcie_rc *rc = NULL; struct cdns_pcie_ep *ep = NULL; - struct gpio_desc *gpiod; + struct gpio_desc *perst_gpiod; void __iomem *base; struct clk *clk; u32 num_lanes; @@ -468,11 +470,10 @@ static int j721e_pcie_probe(struct platform_device *pdev) switch (mode) { case PCI_MODE_RC: - gpiod = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW); - if (IS_ERR(gpiod)) { - ret = PTR_ERR(gpiod); - if (ret != -EPROBE_DEFER) - dev_err(dev, "Failed to get reset GPIO\n"); + perst_gpiod = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW); + if (IS_ERR(perst_gpiod)) { + ret = PTR_ERR(perst_gpiod); + dev_err(dev, "Failed to get reset GPIO\n"); goto err_get_sync; } @@ -498,16 +499,15 @@ static int j721e_pcie_probe(struct platform_device *pdev) /* * "Power Sequencing and Reset Signal Timings" table in - * PCI EXPRESS CARD ELECTROMECHANICAL SPECIFICATION, REV. 3.0 - * 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. + * PCI EXPRESS CARD ELECTROMECHANICAL SPECIFICATION, REV. 5.0 + * indicates PERST# should be deasserted after minimum of 100ms + * after power rails achieve specified operating limits and + * 100us after reference clock gets stable. + * PERST_INACTIVE_US accounts for both delays. */ - if (gpiod) { - usleep_range(100, 200); - gpiod_set_value_cansleep(gpiod, 1); - } + + fsleep(PERST_INACTIVE_US); + gpiod_set_value_cansleep(perst_gpiod, 1); ret = cdns_pcie_host_setup(rc); if (ret < 0) { diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index a4c397434057..80d520be34e6 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -13,6 +13,9 @@ #define PCIE_LINK_RETRAIN_TIMEOUT_MS 1000 +#define PCIE_TPVPERL_MS 100 /* see PCIe CEM r5.0, sec 2.9.2 */ +#define PCIE_TPERST_CLK_US 100 + extern const unsigned char pcie_link_speed[]; extern bool pci_early_dump;