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References: <20220624104420.257368-2-robimarko@gmail.com> <20220707194139.GA328930@bhelgaas>
In-Reply-To: <20220707194139.GA328930@bhelgaas>
From:   Robert Marko <robimarko@gmail.com>
Date:   Fri, 8 Jul 2022 18:39:37 +0200
Message-ID: <CAOX2RU6TFDtMW+3_rfqbUOy4AmEJh+8F8wPtLnJEBtpnzeMbdA@mail.gmail.com>
Subject: Re: [PATCH v4 2/2] PCI: qcom: Move all DBI register accesses after phy_power_on()
To:     Bjorn Helgaas <helgaas@kernel.org>
Cc:     Stanimir Varbanov <svarbanov@mm-sol.com>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        lpieralisi@kernel.org, Rob Herring <robh@kernel.org>, kw@linux.com,
        Bjorn Helgaas <bhelgaas@google.com>, p.zabel@pengutronix.de,
        jingoohan1@gmail.com, linux-pci@vger.kernel.org,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>,
        johan+linaro@kernel.org,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Ansuel Smith <ansuelsmth@gmail.com>
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Precedence: bulk

CC-ing Christian who did a lot of work on 2.1.0 (IPQ806x).

Regards,
Robert

On Thu, 7 Jul 2022 at 21:41, Bjorn Helgaas <helgaas@kernel.org> wrote:
>
> On Fri, Jun 24, 2022 at 12:44:20PM +0200, Robert Marko wrote:
> > IPQ8074 requires the PHY to be powered on before accessing DBI registers.
> > It's not clear whether other variants have the same dependency, but there
> > seems to be no reason for them to be different, so move all the DBI
> > accesses from .init() to .post_init() so they are all after phy_power_on().
> >
> > Signed-off-by: Robert Marko <robimarko@gmail.com>
>
> Would any of the qcom driver folks care to review and ack this?
> Stanimir, Andy, Bjorn A (from get_maintainer.pl)?
>
> > ---
> > Changes in v4:
> > * Move 2.7.0 accesses as well
> > * Correct title and description (Bjorn)
> > ---
> >  drivers/pci/controller/dwc/pcie-qcom.c | 215 ++++++++++++++-----------
> >  1 file changed, 119 insertions(+), 96 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> > index 24708d5d817d..f1a156052fe7 100644
> > --- a/drivers/pci/controller/dwc/pcie-qcom.c
> > +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> > @@ -348,8 +348,6 @@ static int qcom_pcie_init_2_1_0(struct qcom_pcie *pcie)
> >       struct qcom_pcie_resources_2_1_0 *res = &pcie->res.v2_1_0;
> >       struct dw_pcie *pci = pcie->pci;
> >       struct device *dev = pci->dev;
> > -     struct device_node *node = dev->of_node;
> > -     u32 val;
> >       int ret;
> >
> >       /* reset the PCIe interface as uboot can leave it undefined state */
> > @@ -360,8 +358,6 @@ static int qcom_pcie_init_2_1_0(struct qcom_pcie *pcie)
> >       reset_control_assert(res->ext_reset);
> >       reset_control_assert(res->phy_reset);
> >
> > -     writel(1, pcie->parf + PCIE20_PARF_PHY_CTRL);
> > -
> >       ret = regulator_bulk_enable(ARRAY_SIZE(res->supplies), res->supplies);
> >       if (ret < 0) {
> >               dev_err(dev, "cannot enable regulators\n");
> > @@ -408,6 +404,35 @@ static int qcom_pcie_init_2_1_0(struct qcom_pcie *pcie)
> >       if (ret)
> >               goto err_clks;
> >
> > +     return 0;
> > +
> > +err_clks:
> > +     reset_control_assert(res->axi_reset);
> > +err_deassert_axi:
> > +     reset_control_assert(res->por_reset);
> > +err_deassert_por:
> > +     reset_control_assert(res->pci_reset);
> > +err_deassert_pci:
> > +     reset_control_assert(res->phy_reset);
> > +err_deassert_phy:
> > +     reset_control_assert(res->ext_reset);
> > +err_deassert_ext:
> > +     reset_control_assert(res->ahb_reset);
> > +err_deassert_ahb:
> > +     regulator_bulk_disable(ARRAY_SIZE(res->supplies), res->supplies);
> > +
> > +     return ret;
> > +}
> > +
> > +static int qcom_pcie_post_init_2_1_0(struct qcom_pcie *pcie)
> > +{
> > +     struct dw_pcie *pci = pcie->pci;
> > +     struct device *dev = pci->dev;
> > +     struct device_node *node = dev->of_node;
> > +     u32 val;
> > +
> > +     writel(1, pcie->parf + PCIE20_PARF_PHY_CTRL);
> > +
> >       /* enable PCIe clocks and resets */
> >       val = readl(pcie->parf + PCIE20_PARF_PHY_CTRL);
> >       val &= ~BIT(0);
> > @@ -451,23 +476,6 @@ static int qcom_pcie_init_2_1_0(struct qcom_pcie *pcie)
> >              pci->dbi_base + PCIE20_AXI_MSTR_RESP_COMP_CTRL1);
> >
> >       return 0;
> > -
> > -err_clks:
> > -     reset_control_assert(res->axi_reset);
> > -err_deassert_axi:
> > -     reset_control_assert(res->por_reset);
> > -err_deassert_por:
> > -     reset_control_assert(res->pci_reset);
> > -err_deassert_pci:
> > -     reset_control_assert(res->phy_reset);
> > -err_deassert_phy:
> > -     reset_control_assert(res->ext_reset);
> > -err_deassert_ext:
> > -     reset_control_assert(res->ahb_reset);
> > -err_deassert_ahb:
> > -     regulator_bulk_disable(ARRAY_SIZE(res->supplies), res->supplies);
> > -
> > -     return ret;
> >  }
> >
> >  static int qcom_pcie_get_resources_1_0_0(struct qcom_pcie *pcie)
> > @@ -555,16 +563,6 @@ static int qcom_pcie_init_1_0_0(struct qcom_pcie *pcie)
> >               goto err_slave;
> >       }
> >
> > -     /* change DBI base address */
> > -     writel(0, pcie->parf + PCIE20_PARF_DBI_BASE_ADDR);
> > -
> > -     if (IS_ENABLED(CONFIG_PCI_MSI)) {
> > -             u32 val = readl(pcie->parf + PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT);
> > -
> > -             val |= BIT(31);
> > -             writel(val, pcie->parf + PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT);
> > -     }
> > -
> >       return 0;
> >  err_slave:
> >       clk_disable_unprepare(res->slave_bus);
> > @@ -580,6 +578,22 @@ static int qcom_pcie_init_1_0_0(struct qcom_pcie *pcie)
> >       return ret;
> >  }
> >
> > +static int qcom_pcie_post_init_1_0_0(struct qcom_pcie *pcie)
> > +{
> > +
> > +     /* change DBI base address */
> > +     writel(0, pcie->parf + PCIE20_PARF_DBI_BASE_ADDR);
> > +
> > +     if (IS_ENABLED(CONFIG_PCI_MSI)) {
> > +             u32 val = readl(pcie->parf + PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT);
> > +
> > +             val |= BIT(31);
> > +             writel(val, pcie->parf + PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT);
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> >  static void qcom_pcie_2_3_2_ltssm_enable(struct qcom_pcie *pcie)
> >  {
> >       u32 val;
> > @@ -648,7 +662,6 @@ static int qcom_pcie_init_2_3_2(struct qcom_pcie *pcie)
> >       struct qcom_pcie_resources_2_3_2 *res = &pcie->res.v2_3_2;
> >       struct dw_pcie *pci = pcie->pci;
> >       struct device *dev = pci->dev;
> > -     u32 val;
> >       int ret;
> >
> >       ret = regulator_bulk_enable(ARRAY_SIZE(res->supplies), res->supplies);
> > @@ -681,27 +694,6 @@ static int qcom_pcie_init_2_3_2(struct qcom_pcie *pcie)
> >               goto err_slave_clk;
> >       }
> >
> > -     /* enable PCIe clocks and resets */
> > -     val = readl(pcie->parf + PCIE20_PARF_PHY_CTRL);
> > -     val &= ~BIT(0);
> > -     writel(val, pcie->parf + PCIE20_PARF_PHY_CTRL);
> > -
> > -     /* change DBI base address */
> > -     writel(0, pcie->parf + PCIE20_PARF_DBI_BASE_ADDR);
> > -
> > -     /* MAC PHY_POWERDOWN MUX DISABLE  */
> > -     val = readl(pcie->parf + PCIE20_PARF_SYS_CTRL);
> > -     val &= ~BIT(29);
> > -     writel(val, pcie->parf + PCIE20_PARF_SYS_CTRL);
> > -
> > -     val = readl(pcie->parf + PCIE20_PARF_MHI_CLOCK_RESET_CTRL);
> > -     val |= BIT(4);
> > -     writel(val, pcie->parf + PCIE20_PARF_MHI_CLOCK_RESET_CTRL);
> > -
> > -     val = readl(pcie->parf + PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT_V2);
> > -     val |= BIT(31);
> > -     writel(val, pcie->parf + PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT_V2);
> > -
> >       return 0;
> >
> >  err_slave_clk:
> > @@ -722,8 +714,30 @@ static int qcom_pcie_post_init_2_3_2(struct qcom_pcie *pcie)
> >       struct qcom_pcie_resources_2_3_2 *res = &pcie->res.v2_3_2;
> >       struct dw_pcie *pci = pcie->pci;
> >       struct device *dev = pci->dev;
> > +     u32 val;
> >       int ret;
> >
> > +     /* enable PCIe clocks and resets */
> > +     val = readl(pcie->parf + PCIE20_PARF_PHY_CTRL);
> > +     val &= ~BIT(0);
> > +     writel(val, pcie->parf + PCIE20_PARF_PHY_CTRL);
> > +
> > +     /* change DBI base address */
> > +     writel(0, pcie->parf + PCIE20_PARF_DBI_BASE_ADDR);
> > +
> > +     /* MAC PHY_POWERDOWN MUX DISABLE  */
> > +     val = readl(pcie->parf + PCIE20_PARF_SYS_CTRL);
> > +     val &= ~BIT(29);
> > +     writel(val, pcie->parf + PCIE20_PARF_SYS_CTRL);
> > +
> > +     val = readl(pcie->parf + PCIE20_PARF_MHI_CLOCK_RESET_CTRL);
> > +     val |= BIT(4);
> > +     writel(val, pcie->parf + PCIE20_PARF_MHI_CLOCK_RESET_CTRL);
> > +
> > +     val = readl(pcie->parf + PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT_V2);
> > +     val |= BIT(31);
> > +     writel(val, pcie->parf + PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT_V2);
> > +
> >       ret = clk_prepare_enable(res->pipe_clk);
> >       if (ret) {
> >               dev_err(dev, "cannot prepare/enable pipe clock\n");
> > @@ -837,7 +851,6 @@ static int qcom_pcie_init_2_4_0(struct qcom_pcie *pcie)
> >       struct qcom_pcie_resources_2_4_0 *res = &pcie->res.v2_4_0;
> >       struct dw_pcie *pci = pcie->pci;
> >       struct device *dev = pci->dev;
> > -     u32 val;
> >       int ret;
> >
> >       ret = reset_control_assert(res->axi_m_reset);
> > @@ -962,6 +975,33 @@ static int qcom_pcie_init_2_4_0(struct qcom_pcie *pcie)
> >       if (ret)
> >               goto err_clks;
> >
> > +     return 0;
> > +
> > +err_clks:
> > +     reset_control_assert(res->ahb_reset);
> > +err_rst_ahb:
> > +     reset_control_assert(res->pwr_reset);
> > +err_rst_pwr:
> > +     reset_control_assert(res->axi_s_reset);
> > +err_rst_axi_s:
> > +     reset_control_assert(res->axi_m_sticky_reset);
> > +err_rst_axi_m_sticky:
> > +     reset_control_assert(res->axi_m_reset);
> > +err_rst_axi_m:
> > +     reset_control_assert(res->pipe_sticky_reset);
> > +err_rst_pipe_sticky:
> > +     reset_control_assert(res->pipe_reset);
> > +err_rst_pipe:
> > +     reset_control_assert(res->phy_reset);
> > +err_rst_phy:
> > +     reset_control_assert(res->phy_ahb_reset);
> > +     return ret;
> > +}
> > +
> > +static int qcom_pcie_post_init_2_4_0(struct qcom_pcie *pcie)
> > +{
> > +     u32 val;
> > +
> >       /* enable PCIe clocks and resets */
> >       val = readl(pcie->parf + PCIE20_PARF_PHY_CTRL);
> >       val &= ~BIT(0);
> > @@ -984,26 +1024,6 @@ static int qcom_pcie_init_2_4_0(struct qcom_pcie *pcie)
> >       writel(val, pcie->parf + PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT_V2);
> >
> >       return 0;
> > -
> > -err_clks:
> > -     reset_control_assert(res->ahb_reset);
> > -err_rst_ahb:
> > -     reset_control_assert(res->pwr_reset);
> > -err_rst_pwr:
> > -     reset_control_assert(res->axi_s_reset);
> > -err_rst_axi_s:
> > -     reset_control_assert(res->axi_m_sticky_reset);
> > -err_rst_axi_m_sticky:
> > -     reset_control_assert(res->axi_m_reset);
> > -err_rst_axi_m:
> > -     reset_control_assert(res->pipe_sticky_reset);
> > -err_rst_pipe_sticky:
> > -     reset_control_assert(res->pipe_reset);
> > -err_rst_pipe:
> > -     reset_control_assert(res->phy_reset);
> > -err_rst_phy:
> > -     reset_control_assert(res->phy_ahb_reset);
> > -     return ret;
> >  }
> >
> >  static int qcom_pcie_get_resources_2_3_3(struct qcom_pcie *pcie)
> > @@ -1237,7 +1257,6 @@ static int qcom_pcie_init_2_7_0(struct qcom_pcie *pcie)
> >       struct qcom_pcie_resources_2_7_0 *res = &pcie->res.v2_7_0;
> >       struct dw_pcie *pci = pcie->pci;
> >       struct device *dev = pci->dev;
> > -     u32 val;
> >       int ret;
> >
> >       ret = regulator_bulk_enable(ARRAY_SIZE(res->supplies), res->supplies);
> > @@ -1271,6 +1290,28 @@ static int qcom_pcie_init_2_7_0(struct qcom_pcie *pcie)
> >       /* Wait for reset to complete, required on SM8450 */
> >       usleep_range(1000, 1500);
> >
> > +     return 0;
> > +err_disable_clocks:
> > +     clk_bulk_disable_unprepare(res->num_clks, res->clks);
> > +err_disable_regulators:
> > +     regulator_bulk_disable(ARRAY_SIZE(res->supplies), res->supplies);
> > +
> > +     return ret;
> > +}
> > +
> > +static void qcom_pcie_deinit_2_7_0(struct qcom_pcie *pcie)
> > +{
> > +     struct qcom_pcie_resources_2_7_0 *res = &pcie->res.v2_7_0;
> > +
> > +     clk_bulk_disable_unprepare(res->num_clks, res->clks);
> > +     regulator_bulk_disable(ARRAY_SIZE(res->supplies), res->supplies);
> > +}
> > +
> > +static int qcom_pcie_post_init_2_7_0(struct qcom_pcie *pcie)
> > +{
> > +     struct qcom_pcie_resources_2_7_0 *res = &pcie->res.v2_7_0;
> > +     u32 val;
> > +
> >       /* configure PCIe to RC mode */
> >       writel(DEVICE_TYPE_RC, pcie->parf + PCIE20_PARF_DEVICE_TYPE);
> >
> > @@ -1297,27 +1338,6 @@ static int qcom_pcie_init_2_7_0(struct qcom_pcie *pcie)
> >               writel(val, pcie->parf + PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT);
> >       }
> >
> > -     return 0;
> > -err_disable_clocks:
> > -     clk_bulk_disable_unprepare(res->num_clks, res->clks);
> > -err_disable_regulators:
> > -     regulator_bulk_disable(ARRAY_SIZE(res->supplies), res->supplies);
> > -
> > -     return ret;
> > -}
> > -
> > -static void qcom_pcie_deinit_2_7_0(struct qcom_pcie *pcie)
> > -{
> > -     struct qcom_pcie_resources_2_7_0 *res = &pcie->res.v2_7_0;
> > -
> > -     clk_bulk_disable_unprepare(res->num_clks, res->clks);
> > -     regulator_bulk_disable(ARRAY_SIZE(res->supplies), res->supplies);
> > -}
> > -
> > -static int qcom_pcie_post_init_2_7_0(struct qcom_pcie *pcie)
> > -{
> > -     struct qcom_pcie_resources_2_7_0 *res = &pcie->res.v2_7_0;
> > -
> >       /* Set pipe clock as clock source for pcie_pipe_clk_src */
> >       if (pcie->cfg->pipe_clk_need_muxing)
> >               clk_set_parent(res->pipe_clk_src, res->phy_pipe_clk);
> > @@ -1569,6 +1589,7 @@ static const struct dw_pcie_host_ops qcom_pcie_dw_ops = {
> >  static const struct qcom_pcie_ops ops_2_1_0 = {
> >       .get_resources = qcom_pcie_get_resources_2_1_0,
> >       .init = qcom_pcie_init_2_1_0,
> > +     .post_init = qcom_pcie_post_init_2_1_0,
> >       .deinit = qcom_pcie_deinit_2_1_0,
> >       .ltssm_enable = qcom_pcie_2_1_0_ltssm_enable,
> >  };
> > @@ -1577,6 +1598,7 @@ static const struct qcom_pcie_ops ops_2_1_0 = {
> >  static const struct qcom_pcie_ops ops_1_0_0 = {
> >       .get_resources = qcom_pcie_get_resources_1_0_0,
> >       .init = qcom_pcie_init_1_0_0,
> > +     .post_init = qcom_pcie_post_init_1_0_0,
> >       .deinit = qcom_pcie_deinit_1_0_0,
> >       .ltssm_enable = qcom_pcie_2_1_0_ltssm_enable,
> >  };
> > @@ -1595,6 +1617,7 @@ static const struct qcom_pcie_ops ops_2_3_2 = {
> >  static const struct qcom_pcie_ops ops_2_4_0 = {
> >       .get_resources = qcom_pcie_get_resources_2_4_0,
> >       .init = qcom_pcie_init_2_4_0,
> > +     .post_init = qcom_pcie_post_init_2_4_0,
> >       .deinit = qcom_pcie_deinit_2_4_0,
> >       .ltssm_enable = qcom_pcie_2_3_2_ltssm_enable,
> >  };
> > --
> > 2.36.1
> >