Re: [PATCH v3 3/3] PCI: qcom: Add rx margining settings for 16GT/s
From: Manivannan Sadhasivam
Date: Mon Apr 22 2024 - 11:20:38 EST
On Thu, Apr 18, 2024 at 05:09:36PM -0700, Shashank Babu Chinta Venkata wrote:
PCI: qcom: Add RX lane margining settings for 16 GT/s data rate
> Add rx lane margining settings for 16GT/s(GEN 4) data rate. These
RX
16 GT/s
> settings improve link stability while operating at high date rates
> and helps to improve signal quality.
>
> Signed-off-by: Shashank Babu Chinta Venkata <quic_schintav@xxxxxxxxxxx>
> ---
> drivers/pci/controller/dwc/pcie-designware.h | 18 ++++++++++++++
> drivers/pci/controller/dwc/pcie-qcom-common.c | 24 +++++++++++++++++++
> drivers/pci/controller/dwc/pcie-qcom-common.h | 1 +
> drivers/pci/controller/dwc/pcie-qcom-ep.c | 4 +++-
> drivers/pci/controller/dwc/pcie-qcom.c | 4 +++-
> 5 files changed, 49 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> index ad771bb52d29..e8c48855143f 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -203,6 +203,24 @@
>
> #define PCIE_PL_CHK_REG_ERR_ADDR 0xB28
>
> +/*
> + * GEN4 lane margining register definitions
16 GT/s (GEN 4)
> + */
> +#define GEN4_LANE_MARGINING_1_OFF 0xb80
> +#define MARGINING_MAX_VOLTAGE_OFFSET(n) FIELD_PREP(GENMASK(29, 24), n)
> +#define MARGINING_NUM_VOLTAGE_STEPS(n) FIELD_PREP(GENMASK(22, 16), n)
> +#define MARGINING_MAX_TIMING_OFFSET(n) FIELD_PREP(GENMASK(13, 8), n)
> +#define MARGINING_NUM_TIMING_STEPS(n) FIELD_PREP(GENMASK(5, 0), n)
> +
> +#define GEN4_LANE_MARGINING_2_OFF 0xb84
> +#define MARGINING_IND_ERROR_SAMPLER(n) FIELD_PREP(BIT(28), n)
> +#define MARGINING_SAMPLE_REPORTING_METHOD(n) FIELD_PREP(BIT(27), n)
> +#define MARGINING_IND_LEFT_RIGHT_TIMING(n) FIELD_PREP(BIT(26), n)
> +#define MARGINING_IND_UP_DOWN_VOLTAGE(n) FIELD_PREP(BIT(25), n)
> +#define MARGINING_VOLTAGE_SUPPORTED(n) FIELD_PREP(BIT(24), n)
> +#define MARGINING_MAXLANES(n) FIELD_PREP(GENMASK(20, 16), n)
> +#define MARGINING_SAMPLE_RATE_TIMING(n) FIELD_PREP(GENMASK(13, 8), n)
> +#define MARGINING_SAMPLE_RATE_VOLTAGE(n) FIELD_PREP(GENMASK(5, 0), n)
> /*
> * 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-common.c b/drivers/pci/controller/dwc/pcie-qcom-common.c
> index a6f3eb4c3ee6..3279314ae78c 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom-common.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom-common.c
> @@ -46,6 +46,30 @@ void qcom_pcie_common_set_16gt_eq_settings(struct dw_pcie *pci)
> }
> EXPORT_SYMBOL_GPL(qcom_pcie_common_set_16gt_eq_settings);
>
> +void qcom_pcie_common_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(0x24) |
Same comment as previous patch. Are you doing it intentionally for some reason?
- Mani
--
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