On Fri, Feb 14, 2025 at 06:45:39PM +0800, Wenbin Yao wrote:
From: Qiang Yu <quic_qianyu@xxxxxxxxxxx>
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@xxxxxxxxxxx>
Signed-off-by: Wenbin Yao <quic_wenbyao@xxxxxxxxxxx>
---
drivers/phy/qualcomm/phy-qcom-qmp-pcie.c | 96 ++++++++++++++++--------
1 file changed, 63 insertions(+), 33 deletions(-)
diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
index 219266125cf2..b3912c1a6de8 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;
@@ -3976,7 +3977,9 @@ 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;
int ret;
+ bool phy_initialized;
ret = regulator_bulk_enable(cfg->num_vregs, qmp->vregs);
if (ret) {
@@ -3984,10 +3987,18 @@ static int qmp_pcie_init(struct phy *phy)
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;
+ phy_initialized = !!(readl(pcs + cfg->regs[QPHY_START_CTRL]));
+ qmp->skip_init = qmp->nocsr_reset && phy_initialized;
+ /*
+ * Toggle BCR reset for phy that doesn't support no_csr
s/phy/PHY. Here and below.
+ * 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 +4009,12 @@ 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 +4024,8 @@ 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 +4037,10 @@ 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_bulk_assert(cfg->num_resets, qmp->resets);
+ else
+ reset_control_assert(qmp->nocsr_reset);
I'd flip the if condition for readability:
if (qmp->nocsr_reset)
...
else
...
clk_bulk_disable_unprepare(ARRAY_SIZE(qmp_pciephy_clk_l), qmp->clks);
@@ -4042,16 +4059,22 @@ static int qmp_pcie_power_on(struct phy *phy)
unsigned int mask, val;
int ret;
- qphy_setbits(pcs, cfg->regs[QPHY_PCS_POWER_DOWN_CONTROL],
- cfg->pwrdn_ctrl);
+ /*
+ * Write CSR register for phy that doesn't support no_csr
+ * reset or has not been initialized
+ */
+ if (!qmp->skip_init) {
How about:
if (qmp->skip_init)
goto skip_phy_init;
This is my personal preference btw. If anyone feels the other way, feel free
to drop this suggestion.
+ qphy_setbits(pcs, cfg->regs[QPHY_PCS_POWER_DOWN_CONTROL],
+ cfg->pwrdn_ctrl);
- if (qmp->mode == PHY_MODE_PCIE_RC)
- mode_tbls = cfg->tbls_rc;
- else
- mode_tbls = cfg->tbls_ep;
+ if (qmp->mode == PHY_MODE_PCIE_RC)
+ mode_tbls = cfg->tbls_rc;
+ else
+ mode_tbls = cfg->tbls_ep;
- qmp_pcie_init_registers(qmp, &cfg->tbls);
- qmp_pcie_init_registers(qmp, mode_tbls);
+ qmp_pcie_init_registers(qmp, &cfg->tbls);
+ qmp_pcie_init_registers(qmp, mode_tbls);
+ }
ret = clk_bulk_prepare_enable(qmp->num_pipe_clks, qmp->pipe_clks);
if (ret)
@@ -4063,15 +4086,16 @@ static int qmp_pcie_power_on(struct phy *phy)
goto err_disable_pipe_clk;
}
- /* Pull PHY out of reset state */
- qphy_clrbits(pcs, cfg->regs[QPHY_SW_RESET], SW_RESET);
+ if (!qmp->skip_init) {
if (qmp->skip_init)
goto skip_serdes_start;
+ /* Pull PHY out of reset state */
+ qphy_clrbits(pcs, cfg->regs[QPHY_SW_RESET], SW_RESET);
- /* start SerDes and Phy-Coding-Sublayer */
- qphy_setbits(pcs, cfg->regs[QPHY_START_CTRL], SERDES_START | PCS_START);
-
- if (!cfg->skip_start_delay)
- usleep_range(1000, 1200);
+ /* start SerDes and Phy-Coding-Sublayer */
+ qphy_setbits(pcs, cfg->regs[QPHY_START_CTRL], SERDES_START | PCS_START);
+ if (!cfg->skip_start_delay)
+ usleep_range(1000, 1200);
+ }
status = pcs + cfg->regs[QPHY_PCS_STATUS];
mask = cfg->phy_status;
ret = readl_poll_timeout(status, val, !(val & mask), 200,
@@ -4096,16 +4120,22 @@ static int qmp_pcie_power_off(struct phy *phy)
clk_bulk_disable_unprepare(qmp->num_pipe_clks, qmp->pipe_clks);
- /* PHY reset */
- qphy_setbits(qmp->pcs, cfg->regs[QPHY_SW_RESET], SW_RESET);
+ /* If a PHY supports no_csr reset but isn't enabled in the bootloader,
+ * phy settings can be reused during the D3cold -> D0 cycle. So it is
I cannot parse this sentence. If PHY is not initialized, how can you reuse the
settings? Also what is the D3cold->D0 reference?
