From 78634aa71cf36435f3f5e028cefc4a3df61d0ce2 Mon Sep 17 00:00:00 2001
From: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Date: Wed, 25 Sep 2019 10:21:28 +0100
Subject: [PATCH 1/3] PCI: mobiveil: ls_pcie_g4: add Workaround for A-011577

Patch-mainline: Submitted, https://patchwork.kernel.org/patch/10847089/
References: fate#326572

PCIe configuration access to non-existent function triggered
SERROR interrupt exception.

Workaround:
Disable error reporting on AXI bus during the Vendor ID read
transactions in enumeration.

This ERRATA is only for LX2160A Rev1.0, and it will be fixed
in Rev2.0.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
 drivers/pci/host/mobiveil/pcie-layerscape-gen4.c |   37 +++++++++++++++++
 drivers/pci/host/mobiveil/pcie-mobiveil-host.c   |   18 +++++++-
 drivers/pci/host/mobiveil/pcie-mobiveil.h        |    3 +
 3 files changed, 57 insertions(+), 1 deletion(-)

--- a/drivers/pci/host/mobiveil/pcie-layerscape-gen4.c
+++ b/drivers/pci/host/mobiveil/pcie-layerscape-gen4.c
@@ -22,8 +22,13 @@
 
 #include "pcie-mobiveil.h"
 
+#define REV_1_0				(0x10)
+
 /* LUT and PF control registers */
 #define PCIE_LUT_OFF			0x80000
+#define PCIE_LUT_GCR			0x28
+#define PCIE_LUT_GCR_RRE		0
+
 #define PCIE_PF_OFF			0xc0000
 #define PCIE_PF_INT_STAT		0x18
 #define PF_INT_STAT_PABRST		BIT(31)
@@ -40,6 +45,7 @@ struct ls_pcie_g4 {
 	struct mobiveil_pcie pci;
 	struct delayed_work dwork;
 	int irq;
+	u8 rev;
 };
 
 static inline u32 ls_pcie_g4_lut_readl(struct ls_pcie_g4 *pcie, u32 off)
@@ -64,6 +70,15 @@ static inline void ls_pcie_g4_pf_writel(
 	iowrite32(val, pcie->pci.csr_axi_slave_base + PCIE_PF_OFF + off);
 }
 
+static int ls_pcie_g4_host_init(struct mobiveil_pcie *pci)
+{
+	struct ls_pcie_g4 *pcie = to_ls_pcie_g4(pci);
+
+	pcie->rev = mobiveil_csr_readb(pci, PCI_REVISION_ID);
+
+	return 0;
+}
+
 static int ls_pcie_g4_link_up(struct mobiveil_pcie *pci)
 {
 	struct ls_pcie_g4 *pcie = to_ls_pcie_g4(pci);
@@ -202,12 +217,34 @@ static void ls_pcie_g4_reset(struct work
 	ls_pcie_g4_enable_interrupt(pcie);
 }
 
+static int ls_pcie_g4_read_other_conf(struct pci_bus *bus, unsigned int devfn,
+				   int where, int size, u32 *val)
+{
+	struct mobiveil_pcie *pci = bus->sysdata;
+	struct ls_pcie_g4 *pcie = to_ls_pcie_g4(pci);
+	int ret;
+
+	if (pcie->rev == REV_1_0 && where == PCI_VENDOR_ID)
+		ls_pcie_g4_lut_writel(pcie, PCIE_LUT_GCR,
+				      0 << PCIE_LUT_GCR_RRE);
+
+	ret = pci_generic_config_read(bus, devfn, where, size, val);
+
+	if (pcie->rev == REV_1_0 && where == PCI_VENDOR_ID)
+		ls_pcie_g4_lut_writel(pcie, PCIE_LUT_GCR,
+				      1 << PCIE_LUT_GCR_RRE);
+
+	return ret;
+}
+
 static struct mobiveil_rp_ops ls_pcie_g4_rp_ops = {
 	.interrupt_init = ls_pcie_g4_interrupt_init,
+	.read_other_conf = ls_pcie_g4_read_other_conf,
 };
 
 static const struct mobiveil_pab_ops ls_pcie_g4_pab_ops = {
 	.link_up = ls_pcie_g4_link_up,
+	.host_init = ls_pcie_g4_host_init,
 };
 
 static int __init ls_pcie_g4_probe(struct platform_device *pdev)
--- a/drivers/pci/host/mobiveil/pcie-mobiveil-host.c
+++ b/drivers/pci/host/mobiveil/pcie-mobiveil-host.c
@@ -79,9 +79,21 @@ static void __iomem *mobiveil_pcie_map_b
 	return rp->config_axi_slave_base + where;
 }
 
+static int mobiveil_pcie_config_read(struct pci_bus *bus, unsigned int devfn,
+				     int where, int size, u32 *val)
+{
+	struct mobiveil_pcie *pcie = bus->sysdata;
+	struct mobiveil_root_port *rp = &pcie->rp;
+
+	if (bus->number > rp->root_bus_nr && rp->ops->read_other_conf)
+		return rp->ops->read_other_conf(bus, devfn, where, size, val);
+
+	return pci_generic_config_read(bus, devfn, where, size, val);
+}
+
 static struct pci_ops mobiveil_pcie_ops = {
 	.map_bus = mobiveil_pcie_map_bus,
-	.read = pci_generic_config_read,
+	.read = mobiveil_pcie_config_read,
 	.write = pci_generic_config_write,
 };
 
@@ -304,6 +316,10 @@ int mobiveil_host_init(struct mobiveil_p
 	value |= (PCI_CLASS_BRIDGE_PCI << 16);
 	mobiveil_csr_writel(pcie, value, PAB_INTP_AXI_PIO_CLASS);
 
+	/* Platform specific host init */
+	if (pcie->ops->host_init)
+		return pcie->ops->host_init(pcie);
+
 	return 0;
 }
 
--- a/drivers/pci/host/mobiveil/pcie-mobiveil.h
+++ b/drivers/pci/host/mobiveil/pcie-mobiveil.h
@@ -146,6 +146,8 @@ struct mobiveil_pcie;
 
 struct mobiveil_rp_ops {
 	int (*interrupt_init)(struct mobiveil_pcie *pcie);
+	int (*read_other_conf)(struct pci_bus *bus, unsigned int devfn,
+			       int where, int size, u32 *val);
 };
 
 struct mobiveil_root_port {
@@ -162,6 +164,7 @@ struct mobiveil_root_port {
 
 struct mobiveil_pab_ops {
 	int (*link_up)(struct mobiveil_pcie *pcie);
+	int (*host_init)(struct mobiveil_pcie *pcie);
 };
 
 struct mobiveil_pcie {
