| Message ID | 20231107-refclk_always_on-v2-3-de23962fc4b3@quicinc.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | phy: qcom-qmp-pcie: Add support to keep refclk always on | expand |
On Tue, 7 Nov 2023 at 14:26, Krishna chaitanya chundru <quic_krichai@quicinc.com> wrote: > > In PCIe low power states like L1.1 or L1.2 the phy will stop > supplying refclk to endpoint. If endpoint asserts clkreq to bring > back link L0, then RC needs to provide refclk to endpoint. > > If there is some issues in platform with clkreq signal propagation Nit: there are I'd rephrase this in the following way: Some platforms (e.g. ABC DEF) fail to drive the clkreq signal to the host (because it is unconnected ?). Due to that... Other than that: Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> > to host and due to that host will not send refclk which results PCIe link > down. For those platforms phy needs to provide refclk even in low power > states. > > Add a flag to keep refclk always supplied to endpoint. > > Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com> > --- > drivers/phy/qualcomm/phy-qcom-qmp-pcie.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c > index 74d03d217ff2..a8d6d69e3f74 100644 > --- a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c > +++ b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c > @@ -43,6 +43,8 @@ > /* QPHY_PCS_STATUS bit */ > #define PHYSTATUS BIT(6) > #define PHYSTATUS_4_20 BIT(7) > +/* PCS_PCIE_ENDPOINT_REFCLK_CNTRL */ > +#define EPCLK_ALWAYS_ON_EN BIT(6) > > #define PHY_INIT_COMPLETE_TIMEOUT 10000 > > @@ -2264,6 +2266,8 @@ struct qmp_pcie { > struct phy *phy; > int mode; > > + bool refclk_always_on; > + > struct clk_fixed_rate pipe_clk_fixed; > }; > > @@ -3179,6 +3183,10 @@ static void qmp_pcie_init_registers(struct qmp_pcie *qmp, const struct qmp_phy_c > qmp_pcie_configure(pcs, tbls->pcs, tbls->pcs_num); > qmp_pcie_configure(pcs_misc, tbls->pcs_misc, tbls->pcs_misc_num); > > + if (qmp->refclk_always_on && cfg->regs[QPHY_PCS_ENDPOINT_REFCLK_CNTRL]) > + qphy_setbits(pcs_misc, cfg->regs[QPHY_PCS_ENDPOINT_REFCLK_CNTRL], > + EPCLK_ALWAYS_ON_EN); > + > if (cfg->lanes >= 4 && qmp->tcsr_4ln_config) { > qmp_pcie_configure(serdes, cfg->serdes_4ln_tbl, cfg->serdes_4ln_num); > qmp_pcie_init_port_b(qmp, tbls); > @@ -3701,6 +3709,12 @@ static int qmp_pcie_probe(struct platform_device *pdev) > if (ret) > goto err_node_put; > > + qmp->refclk_always_on = of_property_read_bool(dev->of_node, "qcom,refclk-always-on"); > + if (qmp->refclk_always_on && !qmp->cfg->regs[QPHY_PCS_ENDPOINT_REFCLK_CNTRL]) { > + dev_err(dev, "refclk is always on is present but refclk cntrl offset is not present\n"); > + goto err_node_put; > + } > + > ret = phy_pipe_clk_register(qmp, np); > if (ret) > goto err_node_put; > > -- > 2.42.0 > >
diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c index 74d03d217ff2..a8d6d69e3f74 100644 --- a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c +++ b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c @@ -43,6 +43,8 @@ /* QPHY_PCS_STATUS bit */ #define PHYSTATUS BIT(6) #define PHYSTATUS_4_20 BIT(7) +/* PCS_PCIE_ENDPOINT_REFCLK_CNTRL */ +#define EPCLK_ALWAYS_ON_EN BIT(6) #define PHY_INIT_COMPLETE_TIMEOUT 10000 @@ -2264,6 +2266,8 @@ struct qmp_pcie { struct phy *phy; int mode; + bool refclk_always_on; + struct clk_fixed_rate pipe_clk_fixed; }; @@ -3179,6 +3183,10 @@ static void qmp_pcie_init_registers(struct qmp_pcie *qmp, const struct qmp_phy_c qmp_pcie_configure(pcs, tbls->pcs, tbls->pcs_num); qmp_pcie_configure(pcs_misc, tbls->pcs_misc, tbls->pcs_misc_num); + if (qmp->refclk_always_on && cfg->regs[QPHY_PCS_ENDPOINT_REFCLK_CNTRL]) + qphy_setbits(pcs_misc, cfg->regs[QPHY_PCS_ENDPOINT_REFCLK_CNTRL], + EPCLK_ALWAYS_ON_EN); + if (cfg->lanes >= 4 && qmp->tcsr_4ln_config) { qmp_pcie_configure(serdes, cfg->serdes_4ln_tbl, cfg->serdes_4ln_num); qmp_pcie_init_port_b(qmp, tbls); @@ -3701,6 +3709,12 @@ static int qmp_pcie_probe(struct platform_device *pdev) if (ret) goto err_node_put; + qmp->refclk_always_on = of_property_read_bool(dev->of_node, "qcom,refclk-always-on"); + if (qmp->refclk_always_on && !qmp->cfg->regs[QPHY_PCS_ENDPOINT_REFCLK_CNTRL]) { + dev_err(dev, "refclk is always on is present but refclk cntrl offset is not present\n"); + goto err_node_put; + } + ret = phy_pipe_clk_register(qmp, np); if (ret) goto err_node_put;
In PCIe low power states like L1.1 or L1.2 the phy will stop supplying refclk to endpoint. If endpoint asserts clkreq to bring back link L0, then RC needs to provide refclk to endpoint. If there is some issues in platform with clkreq signal propagation to host and due to that host will not send refclk which results PCIe link down. For those platforms phy needs to provide refclk even in low power states. Add a flag to keep refclk always supplied to endpoint. Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com> --- drivers/phy/qualcomm/phy-qcom-qmp-pcie.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)