[PATCH v5 0/2] PCI: mediatek: Add support for EcoNet SoCs

[PATCH v5 0/2] PCI: mediatek: Add support for EcoNet SoCs

[Caleb James DeLisle]

Add EcoNet EN7528 (and EN751221) PCIe support.

Changes from v4:
* Fixed missing Acked-by
* Rebased to 66672af7a095d89f082c5327f3b15bc2f93d558e
* v4: https://lore.kernel.org/linux-mips/20260404182854.2183651-1-cjd@cjdns.fr/

Changes from v3:
* s/initiallized/initialized/
* Use PCIE_T_PVPERL_MS for sleep time
* Use PCI_PM_D3COLD_WAIT for startup wait time
* Clarify comment "Activate INTx interrupts"
* Add MTK_PCIE_RETRAIN quirk for devices which require link re-train
* Do not retrain *all* bridges, only root bridge
* Better comments and logging in retraining logic
* v3: https://lore.kernel.org/linux-mips/20260320094212.696671-1-cjd@cjdns.fr/

Changes from v2:
* mediatek-pcie.yaml -> s/power-domain/power-domains/ and drop example
* Patch 3 dropped as it has been applied (Thanks!)
* v2: https://lore.kernel.org/linux-mips/20260316155157.679533-1-cjd@cjdns.fr/

Changes from v1:
* mediatek-pcie.yaml slot0 needs device-type = "pci", fix dt_binding_check
Link: https://lore.kernel.org/linux-mips/177334026016.3889069.9474337544951486443.robh@kernel.org
* v1: https://lore.kernel.org/linux-mips/20260312165332.569772-1-cjd@cjdns.fr/

This was split from a larger PCIe patchset which crossed multiple
subsystems. I'm not labeling this a v3 because it's a new patchset, but
I'm keeping the historical record anyway.

Changes from econet-pcie v2:
* mediatek-pcie.yaml add missing constraints to PCI node properties
* econet-pcie v2: https://lore.kernel.org/linux-mips/20260309131818.74467-1-cjd@cjdns.fr

Changes from econet-pcie v1:
* pcie-mediatek.c Exclude pcie_retrain_link() when building as a module
* econet-pcie v1: https://lore.kernel.org/linux-mips/20260303190948.694783-1-cjd@cjdns.fr/

Caleb James DeLisle (2):
  dt-bindings: PCI: mediatek: Add support for EcoNet EN7528
  PCI: mediatek: Add support for EcoNet EN7528 SoC

 .../bindings/pci/mediatek-pcie.yaml           |  26 ++++
 drivers/pci/controller/Kconfig                |   2 +-
 drivers/pci/controller/pcie-mediatek.c        | 133 ++++++++++++++++++
 3 files changed, 160 insertions(+), 1 deletion(-)


base-commit: 66672af7a095d89f082c5327f3b15bc2f93d558e
-- 
2.39.5

[PATCH v5 1/2] dt-bindings: PCI: mediatek: Add support for EcoNet EN7528

[Caleb James DeLisle]

Introduce EcoNet EN7528 SoC compatible in MediaTek PCIe controller
binding.

EcoNet PCIe controller has the same configuration model as
Mediatek v2 but is initialized more similarly to an MT7621
PCIe.

Signed-off-by: Caleb James DeLisle <cjd@cjdns.fr>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
---
 .../bindings/pci/mediatek-pcie.yaml           | 26 +++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/Documentation/devicetree/bindings/pci/mediatek-pcie.yaml b/Documentation/devicetree/bindings/pci/mediatek-pcie.yaml
index 0b8c78ec4f91..7e1b0876c291 100644
--- a/Documentation/devicetree/bindings/pci/mediatek-pcie.yaml
+++ b/Documentation/devicetree/bindings/pci/mediatek-pcie.yaml
@@ -14,6 +14,7 @@ properties:
     oneOf:
       - enum:
           - airoha,an7583-pcie
+          - econet,en7528-pcie
           - mediatek,mt2712-pcie
           - mediatek,mt7622-pcie
           - mediatek,mt7629-pcie
@@ -226,6 +227,31 @@ allOf:
 
         mediatek,pbus-csr: false
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: econet,en7528-pcie
+    then:
+      properties:
+        clocks:
+          maxItems: 1
+
+        clock-names:
+          maxItems: 1
+
+        reset: false
+
+        reset-names: false
+
+        power-domains: false
+
+        mediatek,pbus-csr: false
+
+      required:
+        - phys
+        - phy-names
+
 unevaluatedProperties: false
 
 examples:
-- 
2.39.5

[PATCH v5 2/2] PCI: mediatek: Add support for EcoNet EN7528 SoC

[Caleb James DeLisle]

Add support for the PCIe present on the EcoNet EN7528 (and EN751221) SoCs.

These SoCs have a mix of Gen1 and Gen2 capable ports, but the Gen2 ports
require re-training after startup.

Co-developed-by: Ahmed Naseef <naseefkm@gmail.com>
Signed-off-by: Ahmed Naseef <naseefkm@gmail.com>
Signed-off-by: Caleb James DeLisle <cjd@cjdns.fr>
---
 drivers/pci/controller/Kconfig         |   2 +-
 drivers/pci/controller/pcie-mediatek.c | 133 +++++++++++++++++++++++++
 2 files changed, 134 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
index 686349e09cd3..5808d5e407fd 100644
--- a/drivers/pci/controller/Kconfig
+++ b/drivers/pci/controller/Kconfig
@@ -209,7 +209,7 @@ config PCI_MVEBU
 
 config PCIE_MEDIATEK
 	tristate "MediaTek PCIe controller"
-	depends on ARCH_AIROHA || ARCH_MEDIATEK || COMPILE_TEST
+	depends on ARCH_AIROHA || ARCH_MEDIATEK || ECONET || COMPILE_TEST
 	depends on OF
 	depends on PCI_MSI
 	select IRQ_MSI_LIB
diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
index 75722524fe74..915a35825ce1 100644
--- a/drivers/pci/controller/pcie-mediatek.c
+++ b/drivers/pci/controller/pcie-mediatek.c
@@ -7,6 +7,7 @@
  *	   Honghui Zhang <honghui.zhang@mediatek.com>
  */
 
+#include <asm-generic/errno-base.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/iopoll.h>
@@ -14,6 +15,7 @@
 #include <linux/irqchip/chained_irq.h>
 #include <linux/irqchip/irq-msi-lib.h>
 #include <linux/irqdomain.h>
+#include <linux/kconfig.h>
 #include <linux/kernel.h>
 #include <linux/mfd/syscon.h>
 #include <linux/msi.h>
@@ -77,6 +79,7 @@
 
 #define PCIE_CONF_VEND_ID	0x100
 #define PCIE_CONF_DEVICE_ID	0x102
+#define PCIE_CONF_REV_CLASS	0x104
 #define PCIE_CONF_CLASS_ID	0x106
 
 #define PCIE_INT_MASK		0x420
@@ -89,6 +92,11 @@
 #define MSI_MASK		BIT(23)
 #define MTK_MSI_IRQS_NUM	32
 
+#define EN7528_HOST_MODE	0x00804201
+#define EN7528_LINKUP_REG	0x50
+#define EN7528_RC0_LINKUP	BIT(1)
+#define EN7528_RC1_LINKUP	BIT(2)
+
 #define PCIE_AHB_TRANS_BASE0_L	0x438
 #define PCIE_AHB_TRANS_BASE0_H	0x43c
 #define AHB2PCIE_SIZE(x)	((x) & GENMASK(4, 0))
@@ -148,12 +156,15 @@ struct mtk_pcie_port;
  * @MTK_PCIE_FIX_DEVICE_ID: host's device ID needed to be fixed
  * @MTK_PCIE_NO_MSI: Bridge has no MSI support, and relies on an external block
  * @MTK_PCIE_SKIP_RSTB: Skip calling RSTB bits on PCIe probe
+ * @MTK_PCIE_RETRAIN: Re-train link to bridge after startup because some
+ *                    Gen2-capable devices start as Gen1.
  */
 enum mtk_pcie_quirks {
 	MTK_PCIE_FIX_CLASS_ID = BIT(0),
 	MTK_PCIE_FIX_DEVICE_ID = BIT(1),
 	MTK_PCIE_NO_MSI = BIT(2),
 	MTK_PCIE_SKIP_RSTB = BIT(3),
+	MTK_PCIE_RETRAIN = BIT(4),
 };
 
 /**
@@ -753,6 +764,80 @@ static int mtk_pcie_startup_port_v2(struct mtk_pcie_port *port)
 	return 0;
 }
 
+static int mtk_pcie_startup_port_en7528(struct mtk_pcie_port *port)
+{
+	struct mtk_pcie *pcie = port->pcie;
+	struct pci_host_bridge *host = pci_host_bridge_from_priv(pcie);
+	struct resource *mem = NULL;
+	struct resource_entry *entry;
+	u32 val, link_mask;
+	int err;
+
+	entry = resource_list_first_type(&host->windows, IORESOURCE_MEM);
+	if (entry)
+		mem = entry->res;
+	if (!mem)
+		return -EINVAL;
+
+	if (!pcie->cfg) {
+		dev_err(pcie->dev, "EN7528: pciecfg syscon not available\n");
+		return -EINVAL;
+	}
+
+	/* Assert all reset signals */
+	writel(0, port->base + PCIE_RST_CTRL);
+
+	/*
+	 * Enable PCIe link down reset, if link status changed from link up to
+	 * link down, this will reset MAC control registers and configuration
+	 * space.
+	 */
+	writel(PCIE_LINKDOWN_RST_EN, port->base + PCIE_RST_CTRL);
+
+	msleep(PCIE_T_PVPERL_MS);
+
+	/* De-assert PHY, PE, PIPE, MAC and configuration reset */
+	val = readl(port->base + PCIE_RST_CTRL);
+	val |= PCIE_PHY_RSTB | PCIE_PERSTB | PCIE_PIPE_SRSTB |
+	       PCIE_MAC_SRSTB | PCIE_CRSTB;
+	writel(val, port->base + PCIE_RST_CTRL);
+
+	writel(PCIE_CLASS_CODE | PCIE_REVISION_ID,
+	       port->base + PCIE_CONF_REV_CLASS);
+	writel(EN7528_HOST_MODE, port->base);
+
+	link_mask = (port->slot == 0) ? EN7528_RC0_LINKUP : EN7528_RC1_LINKUP;
+
+	/* 100ms timeout value should be enough for Gen1/2 training */
+	err = regmap_read_poll_timeout(pcie->cfg, EN7528_LINKUP_REG, val,
+				       !!(val & link_mask), 20,
+				       PCI_PM_D3COLD_WAIT * USEC_PER_MSEC);
+	if (err) {
+		dev_err(pcie->dev, "EN7528: port%d link timeout\n", port->slot);
+		return -ETIMEDOUT;
+	}
+
+	/* Activate INTx interrupts */
+	val = readl(port->base + PCIE_INT_MASK);
+	val &= ~INTX_MASK;
+	writel(val, port->base + PCIE_INT_MASK);
+
+	if (IS_ENABLED(CONFIG_PCI_MSI))
+		mtk_pcie_enable_msi(port);
+
+	/* Set AHB to PCIe translation windows */
+	val = lower_32_bits(mem->start) |
+	      AHB2PCIE_SIZE(fls(resource_size(mem)));
+	writel(val, port->base + PCIE_AHB_TRANS_BASE0_L);
+
+	val = upper_32_bits(mem->start);
+	writel(val, port->base + PCIE_AHB_TRANS_BASE0_H);
+
+	writel(WIN_ENABLE, port->base + PCIE_AXI_WINDOW0);
+
+	return 0;
+}
+
 static void __iomem *mtk_pcie_map_bus(struct pci_bus *bus,
 				      unsigned int devfn, int where)
 {
@@ -1149,6 +1234,46 @@ static int mtk_pcie_probe(struct platform_device *pdev)
 	if (err)
 		goto put_resources;
 
+	/* EN7528 PCIe initially comes up as Gen1 even if Gen2 is supported.
+	 * The cannonical way to achieve Gen2 is to re-train the link
+	 * immediately after setup. However, to save a lot of duplicated code
+	 * we use pcie_retrain_link() which is usable once we have the pci_dev
+	 * struct for the bridge, i.e. after pci_host_probe(). */
+	if (pcie->soc->quirks & MTK_PCIE_RETRAIN) {
+		int slot = of_get_pci_domain_nr(dev->of_node);
+		struct pci_dev *rc = NULL;
+		int ret = -ENOENT;
+
+		if (slot >= 0)
+			rc = pci_get_slot(host->bus, PCI_DEVFN(slot, 0));
+
+		if (rc) {
+			ret = -EOPNOTSUPP;
+
+			/* pcie_retrain_link() is not an exported symbol but
+			 * this driver supports being built as a loadable
+			 * module. Someone using this on an EN7528 should make
+			 * it builtin, or accept Gen1 PCI. */
+#if IS_BUILTIN(CONFIG_PCIE_MEDIATEK)
+			ret = pcie_retrain_link(rc, true);
+#endif
+		}
+
+		if (ret) {
+			dev_info(dev, "port%d failed to retrain %pe\n", slot,
+				 ERR_PTR(ret));
+		} else {
+			u16 lnksta;
+			u32 speed;
+
+			pcie_capability_read_word(rc, PCI_EXP_LNKSTA, &lnksta);
+			speed = lnksta & PCI_EXP_LNKSTA_CLS;
+
+			dev_info(dev, "port%d link retrained, speed %s\n", slot,
+				 pci_speed_string(pcie_link_speed[speed]));
+		}
+	}
+
 	return 0;
 
 put_resources:
@@ -1264,8 +1389,16 @@ static const struct mtk_pcie_soc mtk_pcie_soc_mt7629 = {
 	.quirks = MTK_PCIE_FIX_CLASS_ID | MTK_PCIE_FIX_DEVICE_ID,
 };
 
+static const struct mtk_pcie_soc mtk_pcie_soc_en7528 = {
+	.ops = &mtk_pcie_ops_v2,
+	.startup = mtk_pcie_startup_port_en7528,
+	.setup_irq = mtk_pcie_setup_irq,
+	.quirks = MTK_PCIE_RETRAIN,
+};
+
 static const struct of_device_id mtk_pcie_ids[] = {
 	{ .compatible = "airoha,an7583-pcie", .data = &mtk_pcie_soc_an7583 },
+	{ .compatible = "econet,en7528-pcie", .data = &mtk_pcie_soc_en7528 },
 	{ .compatible = "mediatek,mt2701-pcie", .data = &mtk_pcie_soc_v1 },
 	{ .compatible = "mediatek,mt7623-pcie", .data = &mtk_pcie_soc_v1 },
 	{ .compatible = "mediatek,mt2712-pcie", .data = &mtk_pcie_soc_mt2712 },
-- 
2.39.5