From 68b6fec37f4c6fa382da4b76039743c4de89b028 Mon Sep 17 00:00:00 2001
From: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Date: Tue, 25 Jun 2019 09:09:35 +0000
Subject: [PATCH] PCI: mobiveil: Add PCIe Gen4 RC driver for NXP Layerscape
 SoCs
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This PCIe controller is based on the Mobiveil GPEX IP, which is
compatible with the PCI Express™ Base Specification, Revision 4.0.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Reviewed-by: Minghuan Lian <Minghuan.Lian@nxp.com>
---
 drivers/pci/controller/mobiveil/Kconfig            |  10 +
 drivers/pci/controller/mobiveil/Makefile           |   1 +
 .../pci/controller/mobiveil/pcie-layerscape-gen4.c | 274 +++++++++++++++++++++
 drivers/pci/controller/mobiveil/pcie-mobiveil.h    |  16 +-
 4 files changed, 299 insertions(+), 2 deletions(-)
 create mode 100644 drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c

--- a/drivers/pci/controller/mobiveil/Kconfig
+++ b/drivers/pci/controller/mobiveil/Kconfig
@@ -21,4 +21,14 @@ config PCIE_MOBIVEIL_PLAT
 	  Soft IP. It has up to 8 outbound and inbound windows
 	  for address translation and it is a PCIe Gen4 IP.
 
+config PCIE_LAYERSCAPE_GEN4
+	bool "Freescale Layerscape PCIe Gen4 controller"
+	depends on PCI
+	depends on OF && (ARM64 || ARCH_LAYERSCAPE)
+	depends on PCI_MSI_IRQ_DOMAIN
+	select PCIE_MOBIVEIL_HOST
+	help
+	  Say Y here if you want PCIe Gen4 controller support on
+	  Layerscape SoCs. The PCIe controller can work in RC or
+	  EP mode according to RCW[HOST_AGT_PEX] setting.
 endmenu
--- a/drivers/pci/controller/mobiveil/Makefile
+++ b/drivers/pci/controller/mobiveil/Makefile
@@ -2,3 +2,4 @@
 obj-$(CONFIG_PCIE_MOBIVEIL) += pcie-mobiveil.o
 obj-$(CONFIG_PCIE_MOBIVEIL_HOST) += pcie-mobiveil-host.o
 obj-$(CONFIG_PCIE_MOBIVEIL_PLAT) += pcie-mobiveil-plat.o
+obj-$(CONFIG_PCIE_LAYERSCAPE_GEN4) += pcie-layerscape-gen4.o
--- /dev/null
+++ b/drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c
@@ -0,0 +1,274 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCIe Gen4 host controller driver for NXP Layerscape SoCs
+ *
+ * Copyright 2019 NXP
+ *
+ * Author: Zhiqiang Hou <Zhiqiang.Hou@nxp.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/of_pci.h>
+#include <linux/of_platform.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/resource.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+
+#include "pcie-mobiveil.h"
+
+/* LUT and PF control registers */
+#define PCIE_LUT_OFF			0x80000
+#define PCIE_PF_OFF			0xc0000
+#define PCIE_PF_INT_STAT		0x18
+#define PF_INT_STAT_PABRST		BIT(31)
+
+#define PCIE_PF_DBG			0x7fc
+#define PF_DBG_LTSSM_MASK		0x3f
+#define PF_DBG_LTSSM_L0			0x2d /* L0 state */
+#define PF_DBG_WE			BIT(31)
+#define PF_DBG_PABR			BIT(27)
+
+#define to_ls_pcie_g4(x)		platform_get_drvdata((x)->pdev)
+
+struct ls_pcie_g4 {
+	struct mobiveil_pcie pci;
+	struct delayed_work dwork;
+	int irq;
+};
+
+static inline u32 ls_pcie_g4_lut_readl(struct ls_pcie_g4 *pcie, u32 off)
+{
+	return ioread32(pcie->pci.csr_axi_slave_base + PCIE_LUT_OFF + off);
+}
+
+static inline void ls_pcie_g4_lut_writel(struct ls_pcie_g4 *pcie,
+					 u32 off, u32 val)
+{
+	iowrite32(val, pcie->pci.csr_axi_slave_base + PCIE_LUT_OFF + off);
+}
+
+static inline u32 ls_pcie_g4_pf_readl(struct ls_pcie_g4 *pcie, u32 off)
+{
+	return ioread32(pcie->pci.csr_axi_slave_base + PCIE_PF_OFF + off);
+}
+
+static inline void ls_pcie_g4_pf_writel(struct ls_pcie_g4 *pcie,
+					u32 off, u32 val)
+{
+	iowrite32(val, pcie->pci.csr_axi_slave_base + PCIE_PF_OFF + off);
+}
+
+static bool ls_pcie_g4_is_bridge(struct ls_pcie_g4 *pcie)
+{
+	struct mobiveil_pcie *mv_pci = &pcie->pci;
+	u32 header_type;
+
+	header_type = csr_readb(mv_pci, PCI_HEADER_TYPE);
+	header_type &= 0x7f;
+
+	return header_type == PCI_HEADER_TYPE_BRIDGE;
+}
+
+static int ls_pcie_g4_link_up(struct mobiveil_pcie *pci)
+{
+	struct ls_pcie_g4 *pcie = to_ls_pcie_g4(pci);
+	u32 state;
+
+	state = ls_pcie_g4_pf_readl(pcie, PCIE_PF_DBG);
+	state =	state & PF_DBG_LTSSM_MASK;
+
+	if (state == PF_DBG_LTSSM_L0)
+		return 1;
+
+	return 0;
+}
+
+static void ls_pcie_g4_disable_interrupt(struct ls_pcie_g4 *pcie)
+{
+	struct mobiveil_pcie *mv_pci = &pcie->pci;
+
+	csr_writel(mv_pci, 0, PAB_INTP_AMBA_MISC_ENB);
+}
+
+static void ls_pcie_g4_enable_interrupt(struct ls_pcie_g4 *pcie)
+{
+	struct mobiveil_pcie *mv_pci = &pcie->pci;
+	u32 val;
+
+	/* Clear the interrupt status */
+	csr_writel(mv_pci, 0xffffffff, PAB_INTP_AMBA_MISC_STAT);
+
+	val = PAB_INTP_INTX_MASK | PAB_INTP_MSI | PAB_INTP_RESET |
+	      PAB_INTP_PCIE_UE | PAB_INTP_IE_PMREDI | PAB_INTP_IE_EC;
+	csr_writel(mv_pci, val, PAB_INTP_AMBA_MISC_ENB);
+}
+
+static void ls_pcie_g4_reinit_hw(struct ls_pcie_g4 *pcie)
+{
+	struct mobiveil_pcie *mv_pci = &pcie->pci;
+	struct device *dev = &mv_pci->pdev->dev;
+	u32 val, act_stat;
+	int to = 100;
+
+	/* Poll for pab_csb_reset to set and PAB activity to clear */
+	do {
+		usleep_range(10, 15);
+		val = ls_pcie_g4_pf_readl(pcie, PCIE_PF_INT_STAT);
+		act_stat = csr_readl(mv_pci, PAB_ACTIVITY_STAT);
+	} while (((val & PF_INT_STAT_PABRST) == 0 || act_stat) && to--);
+	if (to < 0) {
+		dev_err(dev, "Poll PABRST&PABACT timeout\n");
+		return;
+	}
+
+	/* clear PEX_RESET bit in PEX_PF0_DBG register */
+	val = ls_pcie_g4_pf_readl(pcie, PCIE_PF_DBG);
+	val |= PF_DBG_WE;
+	ls_pcie_g4_pf_writel(pcie, PCIE_PF_DBG, val);
+
+	val = ls_pcie_g4_pf_readl(pcie, PCIE_PF_DBG);
+	val |= PF_DBG_PABR;
+	ls_pcie_g4_pf_writel(pcie, PCIE_PF_DBG, val);
+
+	val = ls_pcie_g4_pf_readl(pcie, PCIE_PF_DBG);
+	val &= ~PF_DBG_WE;
+	ls_pcie_g4_pf_writel(pcie, PCIE_PF_DBG, val);
+
+	mobiveil_host_init(mv_pci, true);
+
+	to = 100;
+	while (!ls_pcie_g4_link_up(mv_pci) && to--)
+		usleep_range(200, 250);
+	if (to < 0)
+		dev_err(dev, "PCIe link training timeout\n");
+}
+
+static irqreturn_t ls_pcie_g4_isr(int irq, void *dev_id)
+{
+	struct ls_pcie_g4 *pcie = (struct ls_pcie_g4 *)dev_id;
+	struct mobiveil_pcie *mv_pci = &pcie->pci;
+	u32 val;
+
+	val = csr_readl(mv_pci, PAB_INTP_AMBA_MISC_STAT);
+	if (!val)
+		return IRQ_NONE;
+
+	if (val & PAB_INTP_RESET) {
+		ls_pcie_g4_disable_interrupt(pcie);
+		schedule_delayed_work(&pcie->dwork, msecs_to_jiffies(1));
+	}
+
+	csr_writel(mv_pci, val, PAB_INTP_AMBA_MISC_STAT);
+
+	return IRQ_HANDLED;
+}
+
+static int ls_pcie_g4_interrupt_init(struct mobiveil_pcie *mv_pci)
+{
+	struct ls_pcie_g4 *pcie = to_ls_pcie_g4(mv_pci);
+	struct platform_device *pdev = mv_pci->pdev;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	pcie->irq = platform_get_irq_byname(pdev, "intr");
+	if (pcie->irq < 0) {
+		dev_err(dev, "Can't get 'intr' IRQ, errno = %d\n", pcie->irq);
+		return pcie->irq;
+	}
+	ret = devm_request_irq(dev, pcie->irq, ls_pcie_g4_isr,
+			       IRQF_SHARED, pdev->name, pcie);
+	if (ret) {
+		dev_err(dev, "Can't register PCIe IRQ, errno = %d\n", ret);
+		return  ret;
+	}
+
+	return 0;
+}
+
+static void ls_pcie_g4_reset(struct work_struct *work)
+{
+	struct delayed_work *dwork = container_of(work, struct delayed_work,
+						  work);
+	struct ls_pcie_g4 *pcie = container_of(dwork, struct ls_pcie_g4, dwork);
+	struct mobiveil_pcie *mv_pci = &pcie->pci;
+	u16 ctrl;
+
+	ctrl = csr_readw(mv_pci, PCI_BRIDGE_CONTROL);
+	ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET;
+	csr_writew(mv_pci, ctrl, PCI_BRIDGE_CONTROL);
+	ls_pcie_g4_reinit_hw(pcie);
+	ls_pcie_g4_enable_interrupt(pcie);
+}
+
+static struct mobiveil_rp_ops ls_pcie_g4_rp_ops = {
+	.interrupt_init = ls_pcie_g4_interrupt_init,
+};
+
+static const struct mobiveil_pab_ops ls_pcie_g4_pab_ops = {
+	.link_up = ls_pcie_g4_link_up,
+};
+
+static int __init ls_pcie_g4_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct pci_host_bridge *bridge;
+	struct mobiveil_pcie *mv_pci;
+	struct ls_pcie_g4 *pcie;
+	struct device_node *np = dev->of_node;
+	int ret;
+
+	if (!of_parse_phandle(np, "msi-parent", 0)) {
+		dev_err(dev, "Failed to find msi-parent\n");
+		return -EINVAL;
+	}
+
+	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
+	if (!bridge)
+		return -ENOMEM;
+
+	pcie = pci_host_bridge_priv(bridge);
+	mv_pci = &pcie->pci;
+
+	mv_pci->pdev = pdev;
+	mv_pci->ops = &ls_pcie_g4_pab_ops;
+	mv_pci->rp.ops = &ls_pcie_g4_rp_ops;
+	mv_pci->bridge = bridge;
+
+	platform_set_drvdata(pdev, pcie);
+
+	INIT_DELAYED_WORK(&pcie->dwork, ls_pcie_g4_reset);
+
+	ret = mobiveil_pcie_host_probe(mv_pci);
+	if (ret) {
+		dev_err(dev, "Fail to probe\n");
+		return  ret;
+	}
+
+	if (!ls_pcie_g4_is_bridge(pcie))
+		return -ENODEV;
+
+	ls_pcie_g4_enable_interrupt(pcie);
+
+	return 0;
+}
+
+static const struct of_device_id ls_pcie_g4_of_match[] = {
+	{ .compatible = "fsl,lx2160a-pcie", },
+	{ },
+};
+
+static struct platform_driver ls_pcie_g4_driver = {
+	.driver = {
+		.name = "layerscape-pcie-gen4",
+		.of_match_table = ls_pcie_g4_of_match,
+		.suppress_bind_attrs = true,
+	},
+};
+
+builtin_platform_driver_probe(ls_pcie_g4_driver, ls_pcie_g4_probe);
--- a/drivers/pci/controller/mobiveil/pcie-mobiveil.h
+++ b/drivers/pci/controller/mobiveil/pcie-mobiveil.h
@@ -43,6 +43,8 @@
 #define  PAGE_LO_MASK			0x3ff
 #define  PAGE_SEL_OFFSET_SHIFT		10
 
+#define PAB_ACTIVITY_STAT		0x81c
+
 #define PAB_AXI_PIO_CTRL		0x0840
 #define  APIO_EN_MASK			0xf
 
@@ -51,8 +53,18 @@
 
 #define PAB_INTP_AMBA_MISC_ENB		0x0b0c
 #define PAB_INTP_AMBA_MISC_STAT		0x0b1c
-#define  PAB_INTP_INTX_MASK		0x01e0
-#define  PAB_INTP_MSI_MASK		0x8
+#define  PAB_INTP_RESET			BIT(1)
+#define  PAB_INTP_MSI			BIT(3)
+#define  PAB_INTP_INTA			BIT(5)
+#define  PAB_INTP_INTB			BIT(6)
+#define  PAB_INTP_INTC			BIT(7)
+#define  PAB_INTP_INTD			BIT(8)
+#define  PAB_INTP_PCIE_UE		BIT(9)
+#define  PAB_INTP_IE_PMREDI		BIT(29)
+#define  PAB_INTP_IE_EC			BIT(30)
+#define  PAB_INTP_MSI_MASK		PAB_INTP_MSI
+#define  PAB_INTP_INTX_MASK		(PAB_INTP_INTA | PAB_INTP_INTB |\
+					PAB_INTP_INTC | PAB_INTP_INTD)
 
 #define PAB_AXI_AMAP_CTRL(win)		PAB_REG_ADDR(0x0ba0, win)
 #define  WIN_ENABLE_SHIFT		0
