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Message-Id: <20250226103600.1923047-3-quic_wenbyao@quicinc.com>
Date: Wed, 26 Feb 2025 18:36:00 +0800
From: Wenbin Yao <quic_wenbyao@...cinc.com>
To: vkoul@...nel.org, kishon@...nel.org, p.zabel@...gutronix.de,
dmitry.baryshkov@...aro.org, abel.vesa@...aro.org,
quic_qianyu@...cinc.com, neil.armstrong@...aro.org,
manivannan.sadhasivam@...aro.org, quic_devipriy@...cinc.com,
konrad.dybcio@....qualcomm.com, linux-arm-msm@...r.kernel.org,
linux-phy@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc: quic_wenbyao@...cinc.com
Subject: [PATCH v5 2/2] phy: qcom: qmp-pcie: Add PHY register retention support
From: Qiang Yu <quic_qianyu@...cinc.com>
Some QCOM PCIe PHYs support no_csr reset. Unlike BCR reset which resets the
whole PHY (hardware and register), no_csr reset only resets PHY hardware
but retains register values, which means PHY setting can be skipped during
PHY init if PCIe link is enabled in booltloader and only no_csr is toggled
after that.
Hence, determine whether the PHY has been enabled in bootloader by
verifying QPHY_START_CTRL register. If it's programmed and no_csr reset is
available, skip BCR reset and PHY register setting to establish the PCIe
link with bootloader - programmed PHY settings.
Signed-off-by: Qiang Yu <quic_qianyu@...cinc.com>
Signed-off-by: Wenbin Yao <quic_wenbyao@...cinc.com>
---
drivers/phy/qualcomm/phy-qcom-qmp-pcie.c | 69 ++++++++++++++++++++----
1 file changed, 59 insertions(+), 10 deletions(-)
diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
index 219266125cf2..c3642d1807e4 100644
--- a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
+++ b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
@@ -2805,6 +2805,7 @@ struct qmp_pcie {
const struct qmp_phy_cfg *cfg;
bool tcsr_4ln_config;
+ bool skip_init;
void __iomem *serdes;
void __iomem *pcs;
@@ -3976,18 +3977,38 @@ static int qmp_pcie_init(struct phy *phy)
{
struct qmp_pcie *qmp = phy_get_drvdata(phy);
const struct qmp_phy_cfg *cfg = qmp->cfg;
+ void __iomem *pcs = qmp->pcs;
+ bool phy_initialized = !!(readl(pcs + cfg->regs[QPHY_START_CTRL]));
int ret;
+ qmp->skip_init = qmp->nocsr_reset && phy_initialized;
+ /*
+ * We need to check the existence of init sequences in two cases:
+ * 1. The PHY doesn't support no_csr reset.
+ * 2. The PHY supports no_csr reset but isn't initialized by bootloader.
+ * As we can't skip init in these two cases.
+ */
+ if (!qmp->skip_init && !cfg->tbls.serdes_num) {
+ dev_err(qmp->dev, "no init sequences are available\n");
+ return -EINVAL;
+ }
+
ret = regulator_bulk_enable(cfg->num_vregs, qmp->vregs);
if (ret) {
dev_err(qmp->dev, "failed to enable regulators, err=%d\n", ret);
return ret;
}
- ret = reset_control_bulk_assert(cfg->num_resets, qmp->resets);
- if (ret) {
- dev_err(qmp->dev, "reset assert failed\n");
- goto err_disable_regulators;
+ /*
+ * Toggle BCR reset for PHY that doesn't support no_csr reset or has not
+ * been initialized.
+ */
+ if (!qmp->skip_init) {
+ ret = reset_control_bulk_assert(cfg->num_resets, qmp->resets);
+ if (ret) {
+ dev_err(qmp->dev, "reset assert failed\n");
+ goto err_disable_regulators;
+ }
}
ret = reset_control_assert(qmp->nocsr_reset);
@@ -3998,10 +4019,12 @@ static int qmp_pcie_init(struct phy *phy)
usleep_range(200, 300);
- ret = reset_control_bulk_deassert(cfg->num_resets, qmp->resets);
- if (ret) {
- dev_err(qmp->dev, "reset deassert failed\n");
- goto err_assert_reset;
+ if (!qmp->skip_init) {
+ ret = reset_control_bulk_deassert(cfg->num_resets, qmp->resets);
+ if (ret) {
+ dev_err(qmp->dev, "reset deassert failed\n");
+ goto err_assert_reset;
+ }
}
ret = clk_bulk_prepare_enable(ARRAY_SIZE(qmp_pciephy_clk_l), qmp->clks);
@@ -4011,7 +4034,8 @@ static int qmp_pcie_init(struct phy *phy)
return 0;
err_assert_reset:
- reset_control_bulk_assert(cfg->num_resets, qmp->resets);
+ if (!qmp->skip_init)
+ reset_control_bulk_assert(cfg->num_resets, qmp->resets);
err_disable_regulators:
regulator_bulk_disable(cfg->num_vregs, qmp->vregs);
@@ -4023,7 +4047,10 @@ static int qmp_pcie_exit(struct phy *phy)
struct qmp_pcie *qmp = phy_get_drvdata(phy);
const struct qmp_phy_cfg *cfg = qmp->cfg;
- reset_control_bulk_assert(cfg->num_resets, qmp->resets);
+ if (qmp->nocsr_reset)
+ reset_control_assert(qmp->nocsr_reset);
+ else
+ reset_control_bulk_assert(cfg->num_resets, qmp->resets);
clk_bulk_disable_unprepare(ARRAY_SIZE(qmp_pciephy_clk_l), qmp->clks);
@@ -4042,6 +4069,13 @@ static int qmp_pcie_power_on(struct phy *phy)
unsigned int mask, val;
int ret;
+ /*
+ * Write CSR register for PHY that doesn't support no_csr reset or has not
+ * been initialized.
+ */
+ if (qmp->skip_init)
+ goto skip_tbls_init;
+
qphy_setbits(pcs, cfg->regs[QPHY_PCS_POWER_DOWN_CONTROL],
cfg->pwrdn_ctrl);
@@ -4053,6 +4087,7 @@ static int qmp_pcie_power_on(struct phy *phy)
qmp_pcie_init_registers(qmp, &cfg->tbls);
qmp_pcie_init_registers(qmp, mode_tbls);
+skip_tbls_init:
ret = clk_bulk_prepare_enable(qmp->num_pipe_clks, qmp->pipe_clks);
if (ret)
return ret;
@@ -4063,6 +4098,9 @@ static int qmp_pcie_power_on(struct phy *phy)
goto err_disable_pipe_clk;
}
+ if (qmp->skip_init)
+ goto skip_serdes_start;
+
/* Pull PHY out of reset state */
qphy_clrbits(pcs, cfg->regs[QPHY_SW_RESET], SW_RESET);
@@ -4072,6 +4110,7 @@ static int qmp_pcie_power_on(struct phy *phy)
if (!cfg->skip_start_delay)
usleep_range(1000, 1200);
+skip_serdes_start:
status = pcs + cfg->regs[QPHY_PCS_STATUS];
mask = cfg->phy_status;
ret = readl_poll_timeout(status, val, !(val & mask), 200,
@@ -4096,6 +4135,15 @@ static int qmp_pcie_power_off(struct phy *phy)
clk_bulk_disable_unprepare(qmp->num_pipe_clks, qmp->pipe_clks);
+ /*
+ * While powering off the PHY, only qmp->nocsr_reset needs to be checked. In
+ * this way, no matter whether the PHY settings were initially programmed by
+ * bootloader or PHY driver itself, we can reuse them when PHY is powered on
+ * next time.
+ */
+ if (qmp->nocsr_reset)
+ goto skip_phy_deinit;
+
/* PHY reset */
qphy_setbits(qmp->pcs, cfg->regs[QPHY_SW_RESET], SW_RESET);
@@ -4107,6 +4155,7 @@ static int qmp_pcie_power_off(struct phy *phy)
qphy_clrbits(qmp->pcs, cfg->regs[QPHY_PCS_POWER_DOWN_CONTROL],
cfg->pwrdn_ctrl);
+skip_phy_deinit:
return 0;
}
--
2.34.1
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