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 X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0949C11F69 for ; Wed, 30 Jun 2021 02:50:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9A9EB61D38 for ; Wed, 30 Jun 2021 02:50:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233233AbhF3Cwb (ORCPT ); Tue, 29 Jun 2021 22:52:31 -0400 Received: from mailgw01.mediatek.com ([60.244.123.138]:43464 "EHLO mailgw01.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S232922AbhF3Cw2 (ORCPT ); Tue, 29 Jun 2021 22:52:28 -0400 X-UUID: 7366555a74d84cbc81042b1fe9813542-20210630 X-UUID: 7366555a74d84cbc81042b1fe9813542-20210630 Received: from mtkcas10.mediatek.inc [(172.21.101.39)] by mailgw01.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 926979926; Wed, 30 Jun 2021 10:49:56 +0800 Received: from mtkcas11.mediatek.inc (172.21.101.40) by mtkmbs05n1.mediatek.inc (172.21.101.15) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Wed, 30 Jun 2021 10:49:55 +0800 Received: from localhost.localdomain (10.17.3.153) by mtkcas11.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Wed, 30 Jun 2021 10:49:53 +0800 From: Jianjun Wang To: Bjorn Helgaas , Rob Herring , Lorenzo Pieralisi , Ryder Lee , Matthias Brugger CC: , , , , , Jianjun Wang , , , , , , , Krzysztof Wilczyski , Subject: [PATCH v3 2/2] PCI: mediatek-gen3: Add support for disable dvfsrc voltage request Date: Wed, 30 Jun 2021 10:49:34 +0800 Message-ID: <20210630024934.18903-3-jianjun.wang@mediatek.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20210630024934.18903-1-jianjun.wang@mediatek.com> References: <20210630024934.18903-1-jianjun.wang@mediatek.com> MIME-Version: 1.0 Content-Type: text/plain X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org PCIe Gen3 PHY layer cannot work properly when the requested voltage is lower than a specific level(e.g. 0.55V, it's depends on the chip manufacturing process). When the dvfsrc feature is implemented, the requested voltage may be reduced to a lower level in suspend mode, hence that the MAC layer will assert a HW signal to request the dvfsrc to raise voltage to normal mode, and it will wait the voltage ready signal from dvfsrc to decide if the LTSSM can start normally. When the dvfsrc feature is not implemented, the MAC layer still assert the voltage request to dvfsrc when exit suspend mode, but will not receive the voltage ready signal, in this case, the LTSSM cannot start normally, and the PCIe link will be failed. Add support for disable dvfsrc voltage request, if the property of "disable-dvfsrc-vlt-req" is presented in device node, we assume that the requested voltage is always higher enough to keep the PCIe Gen3 PHY active, and the voltage request to dvfsrc should be disabled. Signed-off-by: Jianjun Wang --- drivers/pci/controller/pcie-mediatek-gen3.c | 31 +++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c index 3c5b97716d40..028014707588 100644 --- a/drivers/pci/controller/pcie-mediatek-gen3.c +++ b/drivers/pci/controller/pcie-mediatek-gen3.c @@ -79,6 +79,9 @@ #define PCIE_ICMD_PM_REG 0x198 #define PCIE_TURN_OFF_LINK BIT(4) +#define PCIE_MISC_CTRL_REG 0x348 +#define PCIE_DISABLE_DVFSRC_VLT_REQ BIT(1) + #define PCIE_TRANS_TABLE_BASE_REG 0x800 #define PCIE_ATR_SRC_ADDR_MSB_OFFSET 0x4 #define PCIE_ATR_TRSL_ADDR_LSB_OFFSET 0x8 @@ -297,6 +300,34 @@ static int mtk_pcie_startup_port(struct mtk_pcie_port *port) val &= ~PCIE_INTX_ENABLE; writel_relaxed(val, port->base + PCIE_INT_ENABLE_REG); + /* + * PCIe Gen3 PHY layer can not work properly when the requested voltage + * is lower than a specific level(e.g. 0.55V, it's depends on + * the chip manufacturing process). + * + * When the dvfsrc feature is implemented, the requested voltage + * might be reduced to a lower level in suspend mode, hence that + * the MAC layer will assert a HW signal to request the dvfsrc + * to raise voltage to normal mode, and it will wait the voltage + * ready signal from dvfsrc to start the LTSSM normally. + * + * When the dvfsrc feature is not implemented, the MAC layer still + * assert the voltage request to dvfsrc when exit suspend mode, + * but will not get the voltage ready signal, in this case, the LTSSM + * cannot start normally, and the PCIe link will be failed. + * + * If the property of "disable-dvfsrc-vlt-req" is presented + * in device node, we assume that the requested voltage is always + * higher enough to keep the PCIe Gen3 PHY active, and the voltage + * request to dvfsrc should be disabled. + */ + val = readl_relaxed(port->base + PCIE_MISC_CTRL_REG); + val &= ~PCIE_DISABLE_DVFSRC_VLT_REQ; + if (of_property_read_bool(port->dev->of_node, "disable-dvfsrc-vlt-req")) + val |= PCIE_DISABLE_DVFSRC_VLT_REQ; + + writel_relaxed(val, port->base + PCIE_MISC_CTRL_REG); + /* Assert all reset signals */ val = readl_relaxed(port->base + PCIE_RST_CTRL_REG); val |= PCIE_MAC_RSTB | PCIE_PHY_RSTB | PCIE_BRG_RSTB | PCIE_PE_RSTB; -- 2.18.0