[PATCH v3 08/18] PCI: rcar-gen4: Separate hardware setup from resource acquisition

[Koichiro Den <den@valinux.co.jp>]

Factor out the hardware setup needed by Root Port recovery into helpers.
Recovery needs to reset and restore the controller while keeping its
clocks enabled and the R-Car Gen5 SoC PHY initialized.

- From rcar_gen4_pcie_common_init(), extract the power reset and mode
  setup. Leave clock enabling and Application/Local reset control in
  common_init(), so recovery can keep the APP registers accessible.

- From rcar_gen4_v4h_v4m_pcie_init() and rcar_gen5_pcie_init(), extract
  the SoC-specific register setup. This allows recovery to restore those
  settings without taking another clock or PHY initialization reference.

- From rcar_gen4_pcie_host_init(), extract the Root Port register setup
  and PERST# release. Both paths need this host-specific sequence after
  the per-SoC initialization or reset.

No functional changes.

Reviewed-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Signed-off-by: Koichiro Den <den@valinux.co.jp>
---
Changes in v3:
  - Add Marek's R-b tag.
  - Clarify the SoC generation and name the .init() functions in the
    commit message. No code changes.

v2: https://lore.kernel.org/r/20260928165230.3397664-8-den@valinux.co.jp/

 drivers/pci/controller/dwc/pcie-rcar-gen4.c | 125 ++++++++++++--------
 1 file changed, 77 insertions(+), 48 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
index e1b748a9d58b..cbd22e6bb44b 100644
--- a/drivers/pci/controller/dwc/pcie-rcar-gen4.c
+++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
@@ -234,20 +234,13 @@ static void rcar_gen4_pcie_stop_link(struct dw_pcie *dw)
 		rcar->drvdata->ltssm_control(rcar, false);
 }
 
-static int rcar_gen4_pcie_common_init(struct rcar_gen4_pcie *rcar)
+/* Clocks must be enabled and the Application/Local reset deasserted. */
+static int rcar_gen4_pcie_reset(struct rcar_gen4_pcie *rcar)
 {
 	struct dw_pcie *dw = &rcar->dw;
 	u32 val;
 	int ret;
 
-	ret = clk_bulk_prepare_enable(DW_PCIE_NUM_CORE_CLKS, dw->core_clks);
-	if (ret) {
-		dev_err(dw->dev, "Enabling core clocks failed\n");
-		return ret;
-	}
-
-	reset_control_deassert(dw->core_rsts[DW_PCIE_CORE_RST].rstc);
-
 	if (!reset_control_status(dw->core_rsts[DW_PCIE_PWR_RST].rstc)) {
 		reset_control_assert(dw->core_rsts[DW_PCIE_PWR_RST].rstc);
 		/*
@@ -266,8 +259,7 @@ static int rcar_gen4_pcie_common_init(struct rcar_gen4_pcie *rcar)
 	} else if (rcar->drvdata->mode == DW_PCIE_EP_TYPE) {
 		val |= DEVICE_TYPE_EP;
 	} else {
-		ret = -EINVAL;
-		goto err_unprepare;
+		return -EINVAL;
 	}
 
 	if (dw->num_lanes < 4)
@@ -277,7 +269,7 @@ static int rcar_gen4_pcie_common_init(struct rcar_gen4_pcie *rcar)
 
 	ret = reset_control_deassert(dw->core_rsts[DW_PCIE_PWR_RST].rstc);
 	if (ret)
-		goto err_unprepare;
+		return ret;
 
 	/*
 	 * Assure the reset is latched and the core is ready for DBI access.
@@ -293,6 +285,26 @@ static int rcar_gen4_pcie_common_init(struct rcar_gen4_pcie *rcar)
 	fsleep(1000);
 
 	return 0;
+}
+
+static int rcar_gen4_pcie_common_init(struct rcar_gen4_pcie *rcar)
+{
+	struct dw_pcie *dw = &rcar->dw;
+	int ret;
+
+	ret = clk_bulk_prepare_enable(DW_PCIE_NUM_CORE_CLKS, dw->core_clks);
+	if (ret) {
+		dev_err(dw->dev, "Enabling core clocks failed\n");
+		return ret;
+	}
+
+	reset_control_deassert(dw->core_rsts[DW_PCIE_CORE_RST].rstc);
+
+	ret = rcar_gen4_pcie_reset(rcar);
+	if (ret)
+		goto err_unprepare;
+
+	return 0;
 
 err_unprepare:
 	reset_control_assert(dw->core_rsts[DW_PCIE_CORE_RST].rstc);
@@ -310,16 +322,10 @@ static void rcar_gen4_pcie_common_deinit(struct rcar_gen4_pcie *rcar)
 	clk_bulk_disable_unprepare(DW_PCIE_NUM_CORE_CLKS, dw->core_clks);
 }
 
-static int rcar_gen4_v4h_v4m_pcie_init(struct rcar_gen4_pcie *rcar)
+static void rcar_gen4_v4h_v4m_pcie_configure(struct rcar_gen4_pcie *rcar)
 {
 	struct dw_pcie *dw = &rcar->dw;
 	u32 val;
-	int ret;
-
-	/* R-Car Gen4 common initialization. */
-	ret = rcar_gen4_pcie_common_init(rcar);
-	if (ret)
-		return ret;
 
 	/* R-Car V4H and V4M specific additional initialization. */
 	val = dw_pcie_readl_dbi(dw, PORT_LANE_SKEW);
@@ -331,6 +337,17 @@ static int rcar_gen4_v4h_v4m_pcie_init(struct rcar_gen4_pcie *rcar)
 	val = readl(rcar->base + PCIEPWRMNGCTRL);
 	val |= APP_CLK_REQ_N | APP_CLK_PM_EN;
 	writel(val, rcar->base + PCIEPWRMNGCTRL);
+}
+
+static int rcar_gen4_v4h_v4m_pcie_init(struct rcar_gen4_pcie *rcar)
+{
+	int ret;
+
+	ret = rcar_gen4_pcie_common_init(rcar);
+	if (ret)
+		return ret;
+
+	rcar_gen4_v4h_v4m_pcie_configure(rcar);
 
 	return 0;
 }
@@ -341,22 +358,11 @@ static void rcar_gen5_pcie_deinit(struct rcar_gen4_pcie *rcar)
 	rcar_gen4_pcie_common_deinit(rcar);
 }
 
-static int rcar_gen5_pcie_init(struct rcar_gen4_pcie *rcar)
+static void rcar_gen5_pcie_configure(struct rcar_gen4_pcie *rcar)
 {
 	struct dw_pcie *dw = &rcar->dw;
-	int ret;
 	u32 val;
 
-	/* R-Car Gen4 and Gen5 common initialization. */
-	ret = rcar_gen4_pcie_common_init(rcar);
-	if (ret)
-		return ret;
-
-	/* R-Car Gen5 specific additional initialization. */
-	ret = phy_init(rcar->phy);
-	if (ret)
-		goto err_unprepare;
-
 	dw_pcie_dbi_ro_wr_en(dw);
 
 	val = dw_pcie_readl_dbi(dw, PORT_LANE_SKEW);
@@ -375,13 +381,25 @@ static int rcar_gen5_pcie_init(struct rcar_gen4_pcie *rcar)
 	val |= APP_CLK_REQ_N | APP_CLK_PM_EN |
 	       APP_READY_ENTR_L23 | APP_REQ_ENTR_L1;
 	writel(val, rcar->base + PCIEPWRMNGCTRL);
+}
 
-	return 0;
+static int rcar_gen5_pcie_init(struct rcar_gen4_pcie *rcar)
+{
+	int ret;
 
-err_unprepare:
-	rcar_gen4_pcie_common_deinit(rcar);
+	ret = rcar_gen4_pcie_common_init(rcar);
+	if (ret)
+		return ret;
 
-	return ret;
+	ret = phy_init(rcar->phy);
+	if (ret) {
+		rcar_gen4_pcie_common_deinit(rcar);
+		return ret;
+	}
+
+	rcar_gen5_pcie_configure(rcar);
+
+	return 0;
 }
 
 static int rcar_gen4_pcie_prepare(struct rcar_gen4_pcie *rcar)
@@ -619,21 +637,11 @@ static void rcar_gen4_pcie_host_perst_assert(struct dw_pcie_rp *pp, bool assert)
 }
 
 /* Host mode */
-static int rcar_gen4_pcie_host_init(struct dw_pcie_rp *pp)
+static int rcar_gen4_pcie_host_setup(struct dw_pcie_rp *pp)
 {
 	struct dw_pcie *dw = to_dw_pcie_from_pp(pp);
-	struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw);
 	int ret;
 
-	if (pp->bridge)
-		pp->bridge->enable_device = rcar_gen4_pcie_enable_device;
-
-	rcar_gen4_pcie_host_perst_assert(pp, true);
-
-	ret = rcar->drvdata->init(rcar);
-	if (ret)
-		return ret;
-
 	/*
 	 * According to the section 3.5.7.2 "RC Mode" in DWC PCIe Dual Mode
 	 * Rev.5.20a and 3.5.6.1 "RC mode" in DWC PCIe RC databook v5.20a, we
@@ -645,13 +653,34 @@ static int rcar_gen4_pcie_host_init(struct dw_pcie_rp *pp)
 
 	ret = rcar_gen4_pcie_host_msi_init(pp);
 	if (ret)
-		goto err;
+		return ret;
 
 	msleep(PCIE_T_PVPERL_MS);	/* pe_rst requires 100msec delay */
-
 	rcar_gen4_pcie_host_perst_assert(pp, false);
 
 	return 0;
+}
+
+static int rcar_gen4_pcie_host_init(struct dw_pcie_rp *pp)
+{
+	struct dw_pcie *dw = to_dw_pcie_from_pp(pp);
+	struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw);
+	int ret;
+
+	if (pp->bridge)
+		pp->bridge->enable_device = rcar_gen4_pcie_enable_device;
+
+	rcar_gen4_pcie_host_perst_assert(pp, true);
+
+	ret = rcar->drvdata->init(rcar);
+	if (ret)
+		return ret;
+
+	ret = rcar_gen4_pcie_host_setup(pp);
+	if (ret)
+		goto err;
+
+	return 0;
 
 err:
 	rcar->drvdata->deinit(rcar);
-- 
2.51.0