From: AngeloGioacchino Del Regno Date: Mon, 4 Apr 2022 14:48:58 +0000 (+0200) Subject: PCI: mediatek-gen3: Assert resets to ensure expected init state X-Git-Tag: v5.17.14~248 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8c90701b94c4a76a1fff6f29c9aa572f44e92a3a;p=thirdparty%2Fkernel%2Fstable.git PCI: mediatek-gen3: Assert resets to ensure expected init state [ Upstream commit 1d565935e3b9ccc682631e0bc6e415a7f48295d9 ] The controller may have been left out of reset by the bootloader, in which case, before the powerup sequence, the controller will be found preconfigured with values that were set before booting the kernel: this produces a controller failure, with the result of a failure during the mtk_pcie_startup_port() sequence as the PCIe link never gets up. To ensure that we get a clean start in an expected state, assert both the PHY and MAC resets before executing the controller power-up sequence. Link: https://lore.kernel.org/r/20220404144858.92390-1-angelogioacchino.delregno@collabora.com Fixes: d3bf75b579b9 ("PCI: mediatek-gen3: Add MediaTek Gen3 driver for MT8192") Signed-off-by: AngeloGioacchino Del Regno Signed-off-by: Lorenzo Pieralisi Signed-off-by: Sasha Levin --- diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c index 7705d61fba4c7..0e27a49ae0c2e 100644 --- a/drivers/pci/controller/pcie-mediatek-gen3.c +++ b/drivers/pci/controller/pcie-mediatek-gen3.c @@ -838,6 +838,14 @@ static int mtk_pcie_setup(struct mtk_gen3_pcie *pcie) if (err) return err; + /* + * The controller may have been left out of reset by the bootloader + * so make sure that we get a clean start by asserting resets here. + */ + reset_control_assert(pcie->phy_reset); + reset_control_assert(pcie->mac_reset); + usleep_range(10, 20); + /* Don't touch the hardware registers before power up */ err = mtk_pcie_power_up(pcie); if (err)