PCI: dwc: intel: PCIe RC controller driver

Add support to PCIe RC controller on Intel Gateway SoCs.
PCIe controller is based of Synopsys DesignWare PCIe core.

Intel PCIe driver requires Upconfigure support, Fast Training
Sequence and link speed configurations. So adding the respective
helper functions in the PCIe DesignWare framework.
It also programs hardware autonomous speed during speed
configuration so defining it in pci_regs.h.

Also, mark Intel PCIe driver depends on MSI IRQ Domain
as Synopsys DesignWare framework depends on the
PCI_MSI_IRQ_DOMAIN.

Signed-off-by: Dilip Kota <eswara.kota@linux.intel.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Andrew Murray <andrew.murray@arm.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Acked-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>

drivers/pci/controller/dwc/Kconfig

@@ -209,6 +209,17 @@ config PCIE_ARTPEC6_EP
 	  Enables support for the PCIe controller in the ARTPEC-6 SoC to work in
 	  endpoint mode. This uses the DesignWare core.
 
+config PCIE_INTEL_GW
+	bool "Intel Gateway PCIe host controller support"
+	depends on OF && (X86 || COMPILE_TEST)
+	depends on PCI_MSI_IRQ_DOMAIN
+	select PCIE_DW_HOST
+	help
+	  Say 'Y' here to enable PCIe Host controller support on Intel
+	  Gateway SoCs.
+	  The PCIe controller uses the DesignWare core plus Intel-specific
+	  hardware wrappers.
+
 config PCIE_KIRIN
 	depends on OF && (ARM64 || COMPILE_TEST)
 	bool "HiSilicon Kirin series SoCs PCIe controllers"

drivers/pci/controller/dwc/Makefile

@@ -13,6 +13,7 @@ obj-$(CONFIG_PCI_LAYERSCAPE_EP) += pci-layerscape-ep.o
 obj-$(CONFIG_PCIE_QCOM) += pcie-qcom.o
 obj-$(CONFIG_PCIE_ARMADA_8K) += pcie-armada8k.o
 obj-$(CONFIG_PCIE_ARTPEC6) += pcie-artpec6.o
+obj-$(CONFIG_PCIE_INTEL_GW) += pcie-intel-gw.o
 obj-$(CONFIG_PCIE_KIRIN) += pcie-kirin.o
 obj-$(CONFIG_PCIE_HISI_STB) += pcie-histb.o
 obj-$(CONFIG_PCI_MESON) += pci-meson.o

drivers/pci/controller/dwc/pcie-designware.c

@@ -12,6 +12,7 @@
 #include <linux/of.h>
 #include <linux/types.h>
 
+#include "../../pci.h"
 #include "pcie-designware.h"
 
 /*
@@ -474,6 +475,61 @@ int dw_pcie_link_up(struct dw_pcie *pci)
 		(!(val & PCIE_PORT_DEBUG1_LINK_IN_TRAINING)));
 }
 
+void dw_pcie_upconfig_setup(struct dw_pcie *pci)
+{
+	u32 val;
+
+	val = dw_pcie_readl_dbi(pci, PCIE_PORT_MULTI_LANE_CTRL);
+	val |= PORT_MLTI_UPCFG_SUPPORT;
+	dw_pcie_writel_dbi(pci, PCIE_PORT_MULTI_LANE_CTRL, val);
+}
+EXPORT_SYMBOL_GPL(dw_pcie_upconfig_setup);
+
+void dw_pcie_link_set_max_speed(struct dw_pcie *pci, u32 link_gen)
+{
+	u32 reg, val;
+	u8 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
+
+	reg = dw_pcie_readl_dbi(pci, offset + PCI_EXP_LNKCTL2);
+	reg &= ~PCI_EXP_LNKCTL2_TLS;
+
+	switch (pcie_link_speed[link_gen]) {
+	case PCIE_SPEED_2_5GT:
+		reg |= PCI_EXP_LNKCTL2_TLS_2_5GT;
+		break;
+	case PCIE_SPEED_5_0GT:
+		reg |= PCI_EXP_LNKCTL2_TLS_5_0GT;
+		break;
+	case PCIE_SPEED_8_0GT:
+		reg |= PCI_EXP_LNKCTL2_TLS_8_0GT;
+		break;
+	case PCIE_SPEED_16_0GT:
+		reg |= PCI_EXP_LNKCTL2_TLS_16_0GT;
+		break;
+	default:
+		/* Use hardware capability */
+		val = dw_pcie_readl_dbi(pci, offset + PCI_EXP_LNKCAP);
+		val = FIELD_GET(PCI_EXP_LNKCAP_SLS, val);
+		reg &= ~PCI_EXP_LNKCTL2_HASD;
+		reg |= FIELD_PREP(PCI_EXP_LNKCTL2_TLS, val);
+		break;
+	}
+
+	dw_pcie_writel_dbi(pci, offset + PCI_EXP_LNKCTL2, reg);
+}
+EXPORT_SYMBOL_GPL(dw_pcie_link_set_max_speed);
+
+void dw_pcie_link_set_n_fts(struct dw_pcie *pci, u32 n_fts)
+{
+	u32 val;
+
+	val = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
+	val &= ~PORT_LOGIC_N_FTS_MASK;
+	val |= n_fts & PORT_LOGIC_N_FTS_MASK;
+	dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, val);
+}
+EXPORT_SYMBOL_GPL(dw_pcie_link_set_n_fts);
+
 static u8 dw_pcie_iatu_unroll_enabled(struct dw_pcie *pci)
 {
 	u32 val;

drivers/pci/controller/dwc/pcie-designware.h

@@ -30,7 +30,12 @@
 #define LINK_WAIT_IATU			9
 
 /* Synopsys-specific PCIe configuration registers */
+#define PCIE_PORT_AFR			0x70C
+#define PORT_AFR_N_FTS_MASK		GENMASK(15, 8)
+#define PORT_AFR_CC_N_FTS_MASK		GENMASK(23, 16)
+
 #define PCIE_PORT_LINK_CONTROL		0x710
+#define PORT_LINK_DLL_LINK_EN		BIT(5)
 #define PORT_LINK_MODE_MASK		GENMASK(21, 16)
 #define PORT_LINK_MODE(n)		FIELD_PREP(PORT_LINK_MODE_MASK, n)
 #define PORT_LINK_MODE_1_LANES		PORT_LINK_MODE(0x1)
@@ -46,6 +51,7 @@
 #define PCIE_PORT_DEBUG1_LINK_IN_TRAINING	BIT(29)
 
 #define PCIE_LINK_WIDTH_SPEED_CONTROL	0x80C
+#define PORT_LOGIC_N_FTS_MASK		GENMASK(7, 0)
 #define PORT_LOGIC_SPEED_CHANGE		BIT(17)
 #define PORT_LOGIC_LINK_WIDTH_MASK	GENMASK(12, 8)
 #define PORT_LOGIC_LINK_WIDTH(n)	FIELD_PREP(PORT_LOGIC_LINK_WIDTH_MASK, n)
@@ -60,6 +66,9 @@
 #define PCIE_MSI_INTR0_MASK		0x82C
 #define PCIE_MSI_INTR0_STATUS		0x830
 
+#define PCIE_PORT_MULTI_LANE_CTRL	0x8C0
+#define PORT_MLTI_UPCFG_SUPPORT		BIT(7)
+
 #define PCIE_ATU_VIEWPORT		0x900
 #define PCIE_ATU_REGION_INBOUND		BIT(31)
 #define PCIE_ATU_REGION_OUTBOUND	0
@@ -273,6 +282,9 @@ void dw_pcie_write_dbi2(struct dw_pcie *pci, u32 reg, size_t size, u32 val);
 u32 dw_pcie_read_atu(struct dw_pcie *pci, u32 reg, size_t size);
 void dw_pcie_write_atu(struct dw_pcie *pci, u32 reg, size_t size, u32 val);
 int dw_pcie_link_up(struct dw_pcie *pci);
+void dw_pcie_upconfig_setup(struct dw_pcie *pci);
+void dw_pcie_link_set_max_speed(struct dw_pcie *pci, u32 link_gen);
+void dw_pcie_link_set_n_fts(struct dw_pcie *pci, u32 n_fts);
 int dw_pcie_wait_for_link(struct dw_pcie *pci);
 void dw_pcie_prog_outbound_atu(struct dw_pcie *pci, int index,
 			       int type, u64 cpu_addr, u64 pci_addr,