From patchwork Mon Nov 4 22:00:05 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lorenzo Bianconi X-Patchwork-Id: 13862155 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 EEF5570816 for ; Mon, 4 Nov 2024 22:00:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730757642; cv=none; b=OriWE+zK1LISZi53CNe8VMy2SKKuicO0xjdsYtO/qK4gzc4FyH53IqcEil6CuI5pvHx7hV6dTxXOv0+57GIjfgR4QMEXgaZhVV7j8DIYcbDsz7v6QIkceljVziUK2lXyOYIV8jUikqRUxkreASxSdqIHS21/NM/9viwujV70EkI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730757642; c=relaxed/simple; bh=+VNwD/bhJNlJ4Sdav4k2eb5Sxm4/XDUeAcINK2T1xvI=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=OatBFfbiVjuPAUgrZ/lEX5uu0ifS0BHcX989dxDeQoXTpdiUZU56s+BSEyIh2RmJhOfudr1eI5XZaINf3c0TBadVWk/RbTzHZE3y4SwC83rWLrKLiINDp4EiICRjGpiJTWcZLEDVtOpsO80uOMwLXd3j3oLuqmJ+8PVG6VFux9s= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=K4L6yKwA; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="K4L6yKwA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 244E3C4CECE; Mon, 4 Nov 2024 22:00:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730757641; bh=+VNwD/bhJNlJ4Sdav4k2eb5Sxm4/XDUeAcINK2T1xvI=; h=From:Date:Subject:To:Cc:From; b=K4L6yKwAxI9ReGi4IgdFDHSO/dOJfh2+ybOFRdVjT/DKszNgF5Kl6ipHld/hwCJNn gOPj0YYseZrnYeShBn2r2Mkh+ILYIpqYuaxY7WGomcgB7MQ1eLRfZFKOzCJSRJ19a6 f1VgxRpCDLS30PkTCetfZuJuij2SumKirrq1QuNH3XzGpvGoDlaskdHIV8r/fXdenZ ila2hhWji/tXeixvKxSp9qN4hQZegVvfMUBCMUqEDdgWT/DWHk4JStfQHaJDuHhoKV 0WEY4MGrtEX4c1c9/M47N65YxJXrwjVKUNyFXWxMuhBzQiD0HZEvMG5CiGePbdzCW6 UKCH2nKUld2Hg== From: Lorenzo Bianconi Date: Mon, 04 Nov 2024 23:00:05 +0100 Subject: [PATCH v2] PCI: mediatek-gen3: Avoid PCIe resetting via PCIE_RSTB for Airoha EN7581 SoC Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20241104-pcie-en7581-rst-fix-v2-1-ffe5839c76d8@kernel.org> X-B4-Tracking: v=1; b=H4sIAORDKWcC/32NQQ6CMBBFr0Jm7Zi2QAVX3sOw0DqFiaYlU9JoC He3cgDzV+8n//0VEglTgnO1glDmxDEUMIcK3HQLIyE/CoNRplG9UTg7JqRwajuNkhb0/MZOW23 bzunaNVCWs1Cpd+t1KDxxWqJ89pOsf+1/X9ZYopra323tvesvT5JAr2OUEYZt274ZHstQtwAAA A== X-Change-ID: 20240920-pcie-en7581-rst-fix-8161658c13c4 To: Ryder Lee , Jianjun Wang , Lorenzo Pieralisi , =?utf-8?q?Krzysztof_Wilczy?= =?utf-8?q?=C5=84ski?= , Rob Herring , Bjorn Helgaas , Matthias Brugger , AngeloGioacchino Del Regno , Manivannan Sadhasivam Cc: Christian Marangi , linux-pci@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org, upstream@airoha.com, Hui Ma , Lorenzo Bianconi X-Mailer: b4 0.14.2 Airoha EN7581 has a hw bug asserting/releasing PCIE_PE_RSTB signal causing occasional PCIe link down issues. In order to overcome the problem, PCIE_RSTB signals are not asserted/released during device probe or suspend/resume phase and the PCIe block is reset using REG_PCI_CONTROL (0x88) and REG_RESET_CONTROL (0x834) registers available via the clock module. Introduce flags field in the mtk_gen3_pcie_pdata struct in order to specify per-SoC capabilities. Tested-by: Hui Ma Signed-off-by: Lorenzo Bianconi --- Changes in v2: - introduce flags field in mtk_gen3_pcie_flags struct instead of adding reset callback - fix the leftover case in mtk_pcie_suspend_noirq routine - add more comments - Link to v1: https://lore.kernel.org/r/20240920-pcie-en7581-rst-fix-v1-1-1043fb63ffc9@kernel.org --- drivers/pci/controller/pcie-mediatek-gen3.c | 59 ++++++++++++++++++++--------- 1 file changed, 41 insertions(+), 18 deletions(-) --- base-commit: 3102ce10f3111e4c3b8fb233dc93f29e220adaf7 change-id: 20240920-pcie-en7581-rst-fix-8161658c13c4 Best regards, diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c index 66ce4b5d309bb6d64618c70ac5e0a529e0910511..8e4704ff3509867fc0ff799e9fb99e71e46756cd 100644 --- a/drivers/pci/controller/pcie-mediatek-gen3.c +++ b/drivers/pci/controller/pcie-mediatek-gen3.c @@ -125,10 +125,18 @@ struct mtk_gen3_pcie; +enum mtk_gen3_pcie_flags { + SKIP_PCIE_RSTB = BIT(0), /* skip PCIE_RSTB signals configuration + * during device probing or suspend/resume + * phase in order to avoid hw bugs/issues. + */ +}; + /** * struct mtk_gen3_pcie_pdata - differentiate between host generations * @power_up: pcie power_up callback * @phy_resets: phy reset lines SoC data. + * @flags: pcie device flags. */ struct mtk_gen3_pcie_pdata { int (*power_up)(struct mtk_gen3_pcie *pcie); @@ -136,6 +144,7 @@ struct mtk_gen3_pcie_pdata { const char *id[MAX_NUM_PHY_RESETS]; int num_resets; } phy_resets; + u32 flags; }; /** @@ -402,22 +411,33 @@ static int mtk_pcie_startup_port(struct mtk_gen3_pcie *pcie) val |= PCIE_DISABLE_DVFSRC_VLT_REQ; writel_relaxed(val, pcie->base + PCIE_MISC_CTRL_REG); - /* Assert all reset signals */ - val = readl_relaxed(pcie->base + PCIE_RST_CTRL_REG); - val |= PCIE_MAC_RSTB | PCIE_PHY_RSTB | PCIE_BRG_RSTB | PCIE_PE_RSTB; - writel_relaxed(val, pcie->base + PCIE_RST_CTRL_REG); - /* - * Described in PCIe CEM specification sections 2.2 (PERST# Signal) - * and 2.2.1 (Initial Power-Up (G3 to S0)). - * The deassertion of PERST# should be delayed 100ms (TPVPERL) - * for the power and clock to become stable. + * Airoha EN7581 has a hw bug asserting/releasing PCIE_PE_RSTB signal + * causing occasional PCIe link down. In order to overcome the issue, + * PCIE_RSTB signals are not asserted/released at this stage and the + * PCIe block is reset using REG_PCI_CONTROL (0x88) and + * REG_RESET_CONTROL (0x834) registers available via the clock module. */ - msleep(100); - - /* De-assert reset signals */ - val &= ~(PCIE_MAC_RSTB | PCIE_PHY_RSTB | PCIE_BRG_RSTB | PCIE_PE_RSTB); - writel_relaxed(val, pcie->base + PCIE_RST_CTRL_REG); + if (!(pcie->soc->flags & SKIP_PCIE_RSTB)) { + /* Assert all reset signals */ + val = readl_relaxed(pcie->base + PCIE_RST_CTRL_REG); + val |= PCIE_MAC_RSTB | PCIE_PHY_RSTB | PCIE_BRG_RSTB | + PCIE_PE_RSTB; + writel_relaxed(val, pcie->base + PCIE_RST_CTRL_REG); + + /* + * Described in PCIe CEM specification sections 2.2 (PERST# Signal) + * and 2.2.1 (Initial Power-Up (G3 to S0)). + * The deassertion of PERST# should be delayed 100ms (TPVPERL) + * for the power and clock to become stable. + */ + msleep(PCIE_T_PVPERL_MS); + + /* De-assert reset signals */ + val &= ~(PCIE_MAC_RSTB | PCIE_PHY_RSTB | PCIE_BRG_RSTB | + PCIE_PE_RSTB); + writel_relaxed(val, pcie->base + PCIE_RST_CTRL_REG); + } /* Check if the link is up or not */ err = readl_poll_timeout(pcie->base + PCIE_LINK_STATUS_REG, val, @@ -1160,10 +1180,12 @@ static int mtk_pcie_suspend_noirq(struct device *dev) return err; } - /* Pull down the PERST# pin */ - val = readl_relaxed(pcie->base + PCIE_RST_CTRL_REG); - val |= PCIE_PE_RSTB; - writel_relaxed(val, pcie->base + PCIE_RST_CTRL_REG); + if (!(pcie->soc->flags & SKIP_PCIE_RSTB)) { + /* Pull down the PERST# pin */ + val = readl_relaxed(pcie->base + PCIE_RST_CTRL_REG); + val |= PCIE_PE_RSTB; + writel_relaxed(val, pcie->base + PCIE_RST_CTRL_REG); + } dev_dbg(pcie->dev, "entered L2 states successfully"); @@ -1214,6 +1236,7 @@ static const struct mtk_gen3_pcie_pdata mtk_pcie_soc_en7581 = { .id[2] = "phy-lane2", .num_resets = 3, }, + .flags = SKIP_PCIE_RSTB, }; static const struct of_device_id mtk_pcie_of_match[] = {