diff options
| author |   qizhong cheng <qizhong.cheng@mediatek.com> | 2021-12-27 21:31:10 +0800 |
|---|---|---|
| committer |   Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> | 2022-01-07 10:21:51 +0000 |
| commit | 65ace9a85fa7f88aec4d9d842061108161fa47bc (patch) | |
| tree | 75b76b6d1bbfa80991bd0dbff0c7ca13d8d13afd /drivers/pci/controller/pcie-mediatek.c | |
| parent | Linux 5.16-rc1 (diff) | |
| download | wireguard-linux-65ace9a85fa7f88aec4d9d842061108161fa47bc.tar.xz wireguard-linux-65ace9a85fa7f88aec4d9d842061108161fa47bc.zip | |
PCI: mediatek: Assert PERST# for 100ms for power and clock to stabilize
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.
Link: https://lore.kernel.org/r/20211227133110.14500-1-qizhong.cheng@mediatek.com
Signed-off-by: qizhong cheng <qizhong.cheng@mediatek.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Pali Rohár <pali@kernel.org>
Diffstat (limited to 'drivers/pci/controller/pcie-mediatek.c')
| -rw-r--r-- | drivers/pci/controller/pcie-mediatek.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c index 2f3f974977a3..b18935e8da89 100644 --- a/drivers/pci/controller/pcie-mediatek.c +++ b/drivers/pci/controller/pcie-mediatek.c @@ -702,6 +702,13 @@ static int mtk_pcie_startup_port_v2(struct mtk_pcie_port *port) */ writel(PCIE_LINKDOWN_RST_EN, port->base + PCIE_RST_CTRL); + /* + * 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(100); + /* De-assert PHY, PE, PIPE, MAC and configuration reset */ val = readl(port->base + PCIE_RST_CTRL); val |= PCIE_PHY_RSTB | PCIE_PERSTB | PCIE_PIPE_SRSTB | |