Re: [PATCH v2 2/6] PCI: qcom: add support for IPQ60xx PCIe controller

[Rob Herring <robh+dt@kernel.org>]

On Wed, May 5, 2021 at 3:18 AM Baruch Siach <baruch@tkos.co.il> wrote:
>
> From: Selvam Sathappan Periakaruppan <speriaka@codeaurora.org>
>
> IPQ60xx series of SoCs have one port of PCIe gen 3. Add support for that
> platform.
>
> The code is based on downstream Codeaurora kernel v5.4. Split out the
> DBI registers access part from .init into .post_init. DBI registers are
> only accessible after phy_power_on().
>
> Signed-off-by: Selvam Sathappan Periakaruppan <speriaka@codeaurora.org>
> Signed-off-by: Baruch Siach <baruch@tkos.co.il>
> ---
> v2:
>   * Drop ATU configuration; rely on common code instead
>
>   * Use more common register macros
>
>   * Use bulk clk and reset APIs
> ---
>  drivers/pci/controller/dwc/pcie-designware.h |   1 +
>  drivers/pci/controller/dwc/pcie-qcom.c       | 150 +++++++++++++++++++
>  2 files changed, 151 insertions(+)
>
> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> index ceb359b6e6a6..346462c74a3e 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -76,6 +76,7 @@
>
>  #define GEN3_RELATED_OFF                       0x890
>  #define GEN3_RELATED_OFF_GEN3_ZRXDC_NONCOMPL   BIT(0)
> +#define GEN3_RELATED_OFF_RXEQ_RGRDLESS_RXTS    BIT(13)
>  #define GEN3_RELATED_OFF_GEN3_EQ_DISABLE       BIT(16)
>  #define GEN3_RELATED_OFF_RATE_SHADOW_SEL_SHIFT 24
>  #define GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK  GENMASK(25, 24)
> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index 8a7a300163e5..93766aee3e7c 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -52,6 +52,10 @@
>  #define PCIE20_PARF_DBI_BASE_ADDR              0x168
>  #define PCIE20_PARF_SLV_ADDR_SPACE_SIZE                0x16C
>  #define PCIE20_PARF_MHI_CLOCK_RESET_CTRL       0x174
> +#define AHB_CLK_EN                             BIT(0)
> +#define MSTR_AXI_CLK_EN                                BIT(1)
> +#define BYPASS                                 BIT(4)
> +
>  #define PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT      0x178
>  #define PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT_V2   0x1A8
>  #define PCIE20_PARF_LTSSM                      0x1B0
> @@ -94,6 +98,12 @@
>  #define SLV_ADDR_SPACE_SZ                      0x10000000
>
>  #define PCIE20_LNK_CONTROL2_LINK_STATUS2       0xa0
> +#define PCIE_CAP_CURR_DEEMPHASIS               BIT(16)

Isn't this a standard register field?

> +#define SPEED_GEN1                             0x1
> +#define SPEED_GEN2                             0x2
> +#define SPEED_GEN3                             0x3

And these?

There's already some common DWC code for setting the link speed.

> +#define AXI_CLK_RATE                           200000000
> +#define RCHNG_CLK_RATE                         100000000
>
>  #define DEVICE_TYPE_RC                         0x4
>
> @@ -168,6 +178,11 @@ struct qcom_pcie_resources_2_7_0 {
>         struct clk *pipe_clk;
>  };
>
> +struct qcom_pcie_resources_2_9_0 {
> +       struct clk_bulk_data clks[5];
> +       struct reset_control *rst;
> +};
> +
>  union qcom_pcie_resources {
>         struct qcom_pcie_resources_1_0_0 v1_0_0;
>         struct qcom_pcie_resources_2_1_0 v2_1_0;
> @@ -175,6 +190,7 @@ union qcom_pcie_resources {
>         struct qcom_pcie_resources_2_3_3 v2_3_3;
>         struct qcom_pcie_resources_2_4_0 v2_4_0;
>         struct qcom_pcie_resources_2_7_0 v2_7_0;
> +       struct qcom_pcie_resources_2_9_0 v2_9_0;
>  };
>
>  struct qcom_pcie;
> @@ -1266,6 +1282,130 @@ static void qcom_pcie_post_deinit_2_7_0(struct qcom_pcie *pcie)
>         clk_disable_unprepare(res->pipe_clk);
>  }
>
> +static int qcom_pcie_get_resources_2_9_0(struct qcom_pcie *pcie)
> +{
> +       struct qcom_pcie_resources_2_9_0 *res = &pcie->res.v2_9_0;
> +       struct dw_pcie *pci = pcie->pci;
> +       struct device *dev = pci->dev;
> +       int ret;
> +
> +       res->clks[0].id = "iface";
> +       res->clks[1].id = "axi_m";
> +       res->clks[2].id = "axi_s";
> +       res->clks[3].id = "axi_bridge";
> +       res->clks[4].id = "rchng";
> +
> +       ret = devm_clk_bulk_get(dev, ARRAY_SIZE(res->clks), res->clks);
> +       if (ret < 0)
> +               return ret;
> +
> +       res->rst = devm_reset_control_array_get_exclusive(dev);
> +       if (IS_ERR(res->rst))
> +               return PTR_ERR(res->rst);
> +
> +       return 0;
> +}
> +
> +static void qcom_pcie_deinit_2_9_0(struct qcom_pcie *pcie)
> +{
> +       struct qcom_pcie_resources_2_9_0 *res = &pcie->res.v2_9_0;
> +
> +       clk_bulk_disable_unprepare(ARRAY_SIZE(res->clks), res->clks);
> +}
> +
> +static int qcom_pcie_init_2_9_0(struct qcom_pcie *pcie)
> +{
> +       struct qcom_pcie_resources_2_9_0 *res = &pcie->res.v2_9_0;
> +       struct device *dev = pcie->pci->dev;
> +       int ret;
> +
> +       ret = reset_control_assert(res->rst);
> +       if (ret) {
> +               dev_err(dev, "reset assert failed (%d)\n", ret);
> +               return ret;
> +       }
> +
> +       usleep_range(2000, 2500);
> +
> +       ret = reset_control_deassert(res->rst);
> +       if (ret) {
> +               dev_err(dev, "reset deassert failed (%d)\n", ret);
> +               return ret;
> +       }
> +
> +       /*
> +        * Don't have a way to see if the reset has completed.
> +        * Wait for some time.
> +        */
> +       usleep_range(2000, 2500);
> +
> +       ret = clk_bulk_prepare_enable(ARRAY_SIZE(res->clks), res->clks);
> +       if (ret)
> +               goto err_reset;
> +
> +       return 0;
> +
> +       /*
> +        * Not checking for failure, will anyway return
> +        * the original failure in 'ret'.
> +        */
> +err_reset:
> +       reset_control_assert(res->rst);
> +
> +       return ret;
> +}
> +
> +static int qcom_pcie_post_init_2_9_0(struct qcom_pcie *pcie)
> +{
> +       struct dw_pcie *pci = pcie->pci;
> +       u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
> +       u32 val;
> +       int i;
> +
> +       writel(SLV_ADDR_SPACE_SZ,
> +               pcie->parf + PCIE20_v3_PARF_SLV_ADDR_SPACE_SIZE);
> +
> +       val = readl(pcie->parf + PCIE20_PARF_PHY_CTRL);
> +       val &= ~BIT(0);
> +       writel(val, pcie->parf + PCIE20_PARF_PHY_CTRL);
> +
> +       writel(0, pcie->parf + PCIE20_PARF_DBI_BASE_ADDR);
> +
> +       writel(DEVICE_TYPE_RC, pcie->parf + PCIE20_PARF_DEVICE_TYPE);
> +       writel(BYPASS | MSTR_AXI_CLK_EN | AHB_CLK_EN,
> +               pcie->parf + PCIE20_PARF_MHI_CLOCK_RESET_CTRL);
> +       writel(GEN3_RELATED_OFF_RXEQ_RGRDLESS_RXTS
> +               | GEN3_RELATED_OFF_GEN3_ZRXDC_NONCOMPL,
> +               pci->dbi_base + GEN3_RELATED_OFF);
> +
> +       writel(MST_WAKEUP_EN | SLV_WAKEUP_EN | MSTR_ACLK_CGC_DIS
> +               | SLV_ACLK_CGC_DIS | CORE_CLK_CGC_DIS |
> +               AUX_PWR_DET | L23_CLK_RMV_DIS | L1_CLK_RMV_DIS,
> +               pcie->parf + PCIE20_PARF_SYS_CTRL);
> +
> +       writel(0, pcie->parf + PCIE20_PARF_Q2A_FLUSH);
> +
> +       dw_pcie_dbi_ro_wr_en(pci);
> +       writel(PCIE_CAP_LINK1_VAL, pci->dbi_base + offset + PCI_EXP_SLTCAP);
> +
> +       /* Configure PCIe link capabilities for ASPM */
> +       val = readl(pci->dbi_base + offset + PCI_EXP_LNKCAP);
> +       val &= ~PCI_EXP_LNKCAP_ASPMS;
> +       writel(val, pci->dbi_base + offset + PCI_EXP_LNKCAP);
> +
> +       writel(PCI_EXP_DEVCTL2_COMP_TMOUT_DIS, pci->dbi_base + offset +
> +                       PCI_EXP_DEVCTL2);
> +
> +       writel(PCIE_CAP_CURR_DEEMPHASIS | SPEED_GEN3,
> +                       pci->dbi_base + offset + PCI_EXP_DEVCTL2);

Doesn't this overwrite the prior register write?

> +
> +       for (i = 0;i < 256;i++)
> +               writel(0x0, pcie->parf + PCIE20_PARF_BDF_TO_SID_TABLE_N
> +                               + (4 * i));
> +
> +       return 0;
> +}
> +
>  static int qcom_pcie_link_up(struct dw_pcie *pci)
>  {
>         u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
> @@ -1456,6 +1596,15 @@ static const struct qcom_pcie_ops ops_1_9_0 = {
>         .config_sid = qcom_pcie_config_sid_sm8250,
>  };
>
> +/* Qcom IP rev.: 2.9.0  Synopsys IP rev.: 5.00a */
> +static const struct qcom_pcie_ops ops_2_9_0 = {
> +       .get_resources = qcom_pcie_get_resources_2_9_0,
> +       .init = qcom_pcie_init_2_9_0,
> +       .post_init = qcom_pcie_post_init_2_9_0,
> +       .deinit = qcom_pcie_deinit_2_9_0,
> +       .ltssm_enable = qcom_pcie_2_3_2_ltssm_enable,
> +};
> +
>  static const struct dw_pcie_ops dw_pcie_ops = {
>         .link_up = qcom_pcie_link_up,
>         .start_link = qcom_pcie_start_link,
> @@ -1555,6 +1704,7 @@ static const struct of_device_id qcom_pcie_match[] = {
>         { .compatible = "qcom,pcie-qcs404", .data = &ops_2_4_0 },
>         { .compatible = "qcom,pcie-sdm845", .data = &ops_2_7_0 },
>         { .compatible = "qcom,pcie-sm8250", .data = &ops_1_9_0 },
> +       { .compatible = "qcom,pcie-ipq6018", .data = &ops_2_9_0 },
>         { }
>  };
>
> --
> 2.30.2
>