[PATCH v4 4/6] PCI: dwc: rcar-gen4: Split .start_link into ltssm_control and speed_control

[Marek Vasut <marek.vasut+renesas@mailbox.org>]

Introduce new .speed_control callback and implement it on R-Car Gen4.
The callback implements the second half of what is currently present
in rcar_gen4_pcie_start_link(), and rcar_gen4_pcie_start_link() does
call the .speed_control callback. This is a preparatory patch for
R-Car Gen5 support, where the .speed_control implementation is
different.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
---
Cc: "Krzysztof Wilczyński" <kwilczynski@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: Manivannan Sadhasivam <mani@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: linux-renesas-soc@vger.kernel.org
---
V2: No change
V3: No change
V4: Rebase on next-20260904
---
 drivers/pci/controller/dwc/pcie-rcar-gen4.c | 39 ++++++++++++++-------
 1 file changed, 26 insertions(+), 13 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
index 04871ac11c348..c768a9c7b3b76 100644
--- a/drivers/pci/controller/dwc/pcie-rcar-gen4.c
+++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
@@ -90,6 +90,7 @@ struct rcar_gen4_pcie_drvdata {
 	int (*init)(struct rcar_gen4_pcie *rcar);
 	void (*deinit)(struct rcar_gen4_pcie *rcar);
 	int (*ltssm_control)(struct rcar_gen4_pcie *rcar, bool enable);
+	int (*speed_control)(struct rcar_gen4_pcie *rcar);
 	enum dw_pcie_device_mode mode;
 };
 
@@ -141,20 +142,10 @@ static int rcar_gen4_pcie_speed_change(struct dw_pcie *dw)
 	return -ETIMEDOUT;
 }
 
-/*
- * Enable LTSSM of this controller and manually initiate the speed change.
- * Always return 0.
- */
-static int rcar_gen4_pcie_start_link(struct dw_pcie *dw)
+static int rcar_gen4_pcie_speed_control(struct rcar_gen4_pcie *rcar)
 {
-	struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw);
-	int i, changes, ret;
-
-	if (rcar->drvdata->ltssm_control) {
-		ret = rcar->drvdata->ltssm_control(rcar, true);
-		if (ret)
-			return ret;
-	}
+	struct dw_pcie *dw = &rcar->dw;
+	int i, changes;
 
 	/*
 	 * Require direct speed change with retrying here if the max_link_speed
@@ -178,6 +169,24 @@ static int rcar_gen4_pcie_start_link(struct dw_pcie *dw)
 	return 0;
 }
 
+/*
+ * Enable LTSSM of this controller and manually initiate the speed change.
+ * Always return 0.
+ */
+static int rcar_gen4_pcie_start_link(struct dw_pcie *dw)
+{
+	struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw);
+	int ret;
+
+	if (rcar->drvdata->ltssm_control) {
+		ret = rcar->drvdata->ltssm_control(rcar, true);
+		if (ret)
+			return ret;
+	}
+
+	return rcar->drvdata->speed_control(rcar);
+}
+
 static void rcar_gen4_pcie_stop_link(struct dw_pcie *dw)
 {
 	struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw);
@@ -916,6 +925,7 @@ static struct rcar_gen4_pcie_drvdata drvdata_r8a779f0_pcie = {
 	.init = rcar_gen4_pcie_common_init,
 	.deinit = rcar_gen4_pcie_common_deinit,
 	.ltssm_control = r8a779f0_pcie_ltssm_control,
+	.speed_control = rcar_gen4_pcie_speed_control,
 	.mode = DW_PCIE_RC_TYPE,
 };
 
@@ -923,6 +933,7 @@ static struct rcar_gen4_pcie_drvdata drvdata_r8a779f0_pcie_ep = {
 	.init = rcar_gen4_pcie_common_init,
 	.deinit = rcar_gen4_pcie_common_deinit,
 	.ltssm_control = r8a779f0_pcie_ltssm_control,
+	.speed_control = rcar_gen4_pcie_speed_control,
 	.mode = DW_PCIE_EP_TYPE,
 };
 
@@ -930,6 +941,7 @@ static struct rcar_gen4_pcie_drvdata drvdata_rcar_gen4_pcie = {
 	.init = rcar_gen4_v4h_v4m_pcie_init,
 	.deinit = rcar_gen4_pcie_common_deinit,
 	.ltssm_control = rcar_gen4_pcie_ltssm_control,
+	.speed_control = rcar_gen4_pcie_speed_control,
 	.mode = DW_PCIE_RC_TYPE,
 };
 
@@ -937,6 +949,7 @@ static struct rcar_gen4_pcie_drvdata drvdata_rcar_gen4_pcie_ep = {
 	.init = rcar_gen4_v4h_v4m_pcie_init,
 	.deinit = rcar_gen4_pcie_common_deinit,
 	.ltssm_control = rcar_gen4_pcie_ltssm_control,
+	.speed_control = rcar_gen4_pcie_speed_control,
 	.mode = DW_PCIE_EP_TYPE,
 };
 
-- 
2.53.0