Re: [PATCH v2 3/3] PCI: qcom: Add rx margining settings for gen4

Manivannan Sadhasivam
2024-04-02T05:47:53Z

On Wed, Mar 20, 2024 at 12:14:47AM -0700, Shashank Babu Chinta Venkata wrote:
> Add rx margining settings for gen4 operation.
>

What is 'rx margining'? As mentioned in the previous patch, use 16 GT/s.

> Signed-off-by: Shashank Babu Chinta Venkata <quic_schintav@quicinc.com>
> ---
> drivers/pci/controller/dwc/pcie-designware.h | 23 +++++++++++++
> drivers/pci/controller/dwc/pcie-qcom-cmn.c | 35 ++++++++++++++++++++
> drivers/pci/controller/dwc/pcie-qcom-cmn.h | 11 +++++-
> drivers/pci/controller/dwc/pcie-qcom-ep.c | 4 ++-
> drivers/pci/controller/dwc/pcie-qcom.c | 4 ++-
> 5 files changed, 74 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> index 064744bfe35a..ce1c5f9c406a 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -206,6 +206,29 @@
>
> #define PCIE_PL_CHK_REG_ERR_ADDR 0xB28
>
> +/*
> + * GEN4 lane margining register definitions
> + */
> +#define GEN4_LANE_MARGINING_1_OFF 0xb80
> +#define MARGINING_MAX_VOLTAGE_OFFSET_MASK GENMASK(29, 24)
> +#define MARGINING_NUM_VOLTAGE_STEPS_MASK GENMASK(22, 16)
> +#define MARGINING_MAX_TIMING_OFFSET_MASK GENMASK(13, 8)
> +#define MARGINING_NUM_TIMING_STEPS_MASK GENMASK(5, 0)
> +#define MARGINING_MAX_VOLTAGE_OFFSET_SHIFT 24
> +#define MARGINING_NUM_VOLTAGE_STEPS_SHIFT 16
> +#define MARGINING_MAX_TIMING_OFFSET_SHIFT 8
> +
> +#define GEN4_LANE_MARGINING_2_OFF 0xb84
> +#define MARGINING_IND_ERROR_SAMPLER BIT(28)
> +#define MARGINING_SAMPLE_REPORTING_METHOD BIT(27)
> +#define MARGINING_IND_LEFT_RIGHT_TIMING BIT(26)
> +#define MARGINING_IND_UP_DOWN_VOLTAGE BIT(25)
> +#define MARGINING_VOLTAGE_SUPPORTED BIT(24)
> +#define MARGINING_MAXLANES_MASK GENMASK(20, 16)
> +#define MARGINING_SAMPLE_RATE_TIMING_MASK GENMASK(13, 8)
> +#define MARGINING_SAMPLE_RATE_VOLTAGE_MASK GENMASK(5, 0)
> +#define MARGINING_MAXLANES_SHIFT 16
> +#define MARGINING_SAMPLE_RATE_TIMING_SHIFT 8

Add a newline

> /*
> * iATU Unroll-specific register definitions
> * From 4.80 core version the address translation will be made by unroll
> diff --git a/drivers/pci/controller/dwc/pcie-qcom-cmn.c b/drivers/pci/controller/dwc/pcie-qcom-cmn.c
> index 208a55e8e9a1..bf6b27ee8327 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom-cmn.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom-cmn.c
> @@ -53,6 +53,41 @@ void qcom_pcie_cmn_set_16gt_eq_settings(struct dw_pcie *pci)
> }
> EXPORT_SYMBOL_GPL(qcom_pcie_cmn_set_16gt_eq_settings);
>
> +void qcom_pcie_cmn_set_16gt_rx_margining_settings(struct dw_pcie *pci)
> +{
> + u32 reg;
> +
> + reg = dw_pcie_readl_dbi(pci, GEN4_LANE_MARGINING_1_OFF);
> + reg &= ~MARGINING_MAX_VOLTAGE_OFFSET_MASK;
> + reg |= (MARGINING_MAX_VOLTAGE_OFFSET_VAL <<
> + MARGINING_MAX_VOLTAGE_OFFSET_SHIFT);

Same comment as previous patch to use FIELD_* macros.

- Mani

--
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