PCI: mediatek-gen3: Add mtk_gen3_pcie_pdata data structure

Introduce mtk_gen3_pcie_pdata data structure in order to define
multiple callbacks for each supported SoC.

This is a preliminary patch to introduce EN7581 PCIe support.

Link: https://lore.kernel.org/linux-pci/c193d1a87505d045e2e0ef33317bce17012ee095.1720022580.git.lorenzo@kernel.org
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Tested-by: Zhengping Zhang <zhengping.zhang@airoha.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Acked-by: Jianjun Wang <jianjun.wang@mediatek.com>

Author: LorenzoBianconi

drivers/pci/controller/pcie-mediatek-gen3.c

@@ -100,6 +100,16 @@
 #define PCIE_ATR_TLP_TYPE_MEM		PCIE_ATR_TLP_TYPE(0)
 #define PCIE_ATR_TLP_TYPE_IO		PCIE_ATR_TLP_TYPE(2)
 
+struct mtk_gen3_pcie;
+
+/**
+ * struct mtk_gen3_pcie_pdata - differentiate between host generations
+ * @power_up: pcie power_up callback
+ */
+struct mtk_gen3_pcie_pdata {
+	int (*power_up)(struct mtk_gen3_pcie *pcie);
+};
+
 /**
  * struct mtk_msi_set - MSI information for each set
  * @base: IO mapped register base
@@ -131,6 +141,7 @@ struct mtk_msi_set {
  * @msi_sets: MSI sets information
  * @lock: lock protecting IRQ bit map
  * @msi_irq_in_use: bit map for assigned MSI IRQ
+ * @soc: pointer to SoC-dependent operations
  */
 struct mtk_gen3_pcie {
 	struct device *dev;
@@ -151,6 +162,8 @@ struct mtk_gen3_pcie {
 	struct mtk_msi_set msi_sets[PCIE_MSI_SET_NUM];
 	struct mutex lock;
 	DECLARE_BITMAP(msi_irq_in_use, PCIE_MSI_IRQS_NUM);
+
+	const struct mtk_gen3_pcie_pdata *soc;
 };
 
 /* LTSSM state in PCIE_LTSSM_STATUS_REG bit[28:24] */
@@ -904,7 +917,7 @@ static int mtk_pcie_setup(struct mtk_gen3_pcie *pcie)
 	usleep_range(10, 20);
 
 	/* Don't touch the hardware registers before power up */
-	err = mtk_pcie_power_up(pcie);
+	err = pcie->soc->power_up(pcie);
 	if (err)
 		return err;
 
@@ -939,6 +952,7 @@ static int mtk_pcie_probe(struct platform_device *pdev)
 	pcie = pci_host_bridge_priv(host);
 
 	pcie->dev = dev;
+	pcie->soc = device_get_match_data(dev);
 	platform_set_drvdata(pdev, pcie);
 
 	err = mtk_pcie_setup(pcie);
@@ -1054,7 +1068,7 @@ static int mtk_pcie_resume_noirq(struct device *dev)
 	struct mtk_gen3_pcie *pcie = dev_get_drvdata(dev);
 	int err;
 
-	err = mtk_pcie_power_up(pcie);
+	err = pcie->soc->power_up(pcie);
 	if (err)
 		return err;
 
@@ -1074,8 +1088,12 @@ static const struct dev_pm_ops mtk_pcie_pm_ops = {
 				  mtk_pcie_resume_noirq)
 };
 
+static const struct mtk_gen3_pcie_pdata mtk_pcie_soc_mt8192 = {
+	.power_up = mtk_pcie_power_up,
+};
+
 static const struct of_device_id mtk_pcie_of_match[] = {
-	{ .compatible = "mediatek,mt8192-pcie" },
+	{ .compatible = "mediatek,mt8192-pcie", .data = &mtk_pcie_soc_mt8192 },
 	{},
 };
 MODULE_DEVICE_TABLE(of, mtk_pcie_of_match);