| Message ID | 20240413004120.1099089-2-dlemoal@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | rockchip rk3399 port initialization fixes | expand |
On Sat, Apr 13, 2024 at 09:41:19AM +0900, Damien Le Moal wrote: > The PCIe specifications (PCIe CEM r5.1, sec 2.9.2) mandate that the > PERST# signal must remain asserted for at least 100 usec (Tperst-clk) > after the PCIe reference clock becomes stable (if a reference clock is > supplied), and for at least 100 msec after the power is stable (Tpvperl, > defined by the macro PCIE_T_PVPERL_MS). > > Modify rockchip_pcie_host_init_port() to satisfy these constraints by > adding a sleep period before deasserting PERST# using the ep_gpio GPIO. > Since Tperst-clk is the shorter wait time, add an msleep() call for the > longer PCIE_T_PVPERL_MS milliseconds to handle both timing requirements. > > Signed-off-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> - Mani > --- > drivers/pci/controller/pcie-rockchip-host.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c > index 300b9dc85ecc..fc868251e570 100644 > --- a/drivers/pci/controller/pcie-rockchip-host.c > +++ b/drivers/pci/controller/pcie-rockchip-host.c > @@ -322,6 +322,7 @@ static int rockchip_pcie_host_init_port(struct rockchip_pcie *rockchip) > rockchip_pcie_write(rockchip, PCIE_CLIENT_LINK_TRAIN_ENABLE, > PCIE_CLIENT_CONFIG); > > + msleep(PCIE_T_PVPERL_MS); > gpiod_set_value_cansleep(rockchip->ep_gpio, 1); > > /* 500ms timeout value should be enough for Gen1/2 training */ > -- > 2.44.0 > >
diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c index 300b9dc85ecc..fc868251e570 100644 --- a/drivers/pci/controller/pcie-rockchip-host.c +++ b/drivers/pci/controller/pcie-rockchip-host.c @@ -322,6 +322,7 @@ static int rockchip_pcie_host_init_port(struct rockchip_pcie *rockchip) rockchip_pcie_write(rockchip, PCIE_CLIENT_LINK_TRAIN_ENABLE, PCIE_CLIENT_CONFIG); + msleep(PCIE_T_PVPERL_MS); gpiod_set_value_cansleep(rockchip->ep_gpio, 1); /* 500ms timeout value should be enough for Gen1/2 training */
The PCIe specifications (PCIe CEM r5.1, sec 2.9.2) mandate that the PERST# signal must remain asserted for at least 100 usec (Tperst-clk) after the PCIe reference clock becomes stable (if a reference clock is supplied), and for at least 100 msec after the power is stable (Tpvperl, defined by the macro PCIE_T_PVPERL_MS). Modify rockchip_pcie_host_init_port() to satisfy these constraints by adding a sleep period before deasserting PERST# using the ep_gpio GPIO. Since Tperst-clk is the shorter wait time, add an msleep() call for the longer PCIE_T_PVPERL_MS milliseconds to handle both timing requirements. Signed-off-by: Damien Le Moal <dlemoal@kernel.org> --- drivers/pci/controller/pcie-rockchip-host.c | 1 + 1 file changed, 1 insertion(+)