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From: Frank Wunderlich <linux@fw-web.de>
To: linux-mediatek@lists.infradead.org
Cc: "Frank Wunderlich" <frank-w@public-files.de>,
	"Ryder Lee" <ryder.lee@mediatek.com>,
	"Jianjun Wang" <jianjun.wang@mediatek.com>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Rob Herring" <robh@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Matthias Brugger" <matthias.bgg@gmail.com>,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH] PCI: mediatek-gen3: handle PERST after reset
Date: Sun,  2 Apr 2023 15:13:47 +0200	[thread overview]
Message-ID: <20230402131347.99268-1-linux@fw-web.de> (raw)

From: Frank Wunderlich <frank-w@public-files.de>

De-assert PERST in separate step after reset signals to fully comply
the PCIe CEM clause 2.2.

This fixes some NVME detection issues on mt7986.

Fixes: d3bf75b579b9 ("PCI: mediatek-gen3: Add MediaTek Gen3 driver for MT8192")
Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
---
Patch is taken from user Ruslan aka RRKh61 (permitted me to send it
with me as author).

https://forum.banana-pi.org/t/bpi-r3-nvme-connection-issue/14563/17
---
 drivers/pci/controller/pcie-mediatek-gen3.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c
index b8612ce5f4d0..176b1a04565d 100644
--- a/drivers/pci/controller/pcie-mediatek-gen3.c
+++ b/drivers/pci/controller/pcie-mediatek-gen3.c
@@ -350,7 +350,13 @@ static int mtk_pcie_startup_port(struct mtk_gen3_pcie *pcie)
 	msleep(100);
 
 	/* De-assert reset signals */
-	val &= ~(PCIE_MAC_RSTB | PCIE_PHY_RSTB | PCIE_BRG_RSTB | PCIE_PE_RSTB);
+	val &= ~(PCIE_MAC_RSTB | PCIE_PHY_RSTB | PCIE_BRG_RSTB);
+	writel_relaxed(val, pcie->base + PCIE_RST_CTRL_REG);
+
+	msleep(100);
+
+	/* De-assert PERST# signals */
+	val &= ~(PCIE_PE_RSTB);
 	writel_relaxed(val, pcie->base + PCIE_RST_CTRL_REG);
 
 	/* Check if the link is up or not */
-- 
2.34.1


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             reply	other threads:[~2023-04-02 13:14 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-02 13:13 Frank Wunderlich [this message]
2023-04-26 17:41 ` Aw: [PATCH] PCI: mediatek-gen3: handle PERST after reset Frank Wunderlich
2023-04-27  8:31   ` Jianjun Wang (王建军)
2023-04-28  5:50     ` Frank Wunderlich
2023-04-29  3:15       ` Jianjun Wang (王建军)
2023-04-29  9:03         ` Frank Wunderlich
2023-05-01  7:51           ` Frank Wunderlich
2023-04-28 20:09 ` Bjorn Helgaas
  -- strict thread matches above, loose matches on Subject: below --
2023-04-02 13:11 Frank Wunderlich

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