[PATCHv2 0/2] PCI: ls_pcie_g4: add 2 workarounds

[PATCHv2 0/2] PCI: ls_pcie_g4: add 2 workarounds

[Z.q. Hou]

From: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>

This patchset adds 2 workarounds for NXP Layerscape Gen4 PCIe controller
driver.

Hou Zhiqiang (2):
  PCI: mobiveil: ls_pcie_g4: add Workaround for A-011577
  PCI: mobiveil: ls_pcie_g4: add Workaround for A-011451

depends on patchset:
 https://patchwork.ozlabs.org/project/linux-pci/list/?series=76942

 .../controller/mobiveil/pci-layerscape-gen4.c | 52 +++++++++++++++++++
 .../controller/mobiveil/pcie-mobiveil-host.c  | 17 +++++-
 .../pci/controller/mobiveil/pcie-mobiveil.h   |  7 +++
 3 files changed, 75 insertions(+), 1 deletion(-)

-- 
2.17.1

[PATCHv2 1/2] PCI: mobiveil: ls_pcie_g4: add Workaround for A-011577

[Z.q. Hou]

From: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>

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>
---
V2:
 - Only apply the workaround for Rev1.0.

 .../controller/mobiveil/pci-layerscape-gen4.c | 37 +++++++++++++++++++
 .../controller/mobiveil/pcie-mobiveil-host.c  | 17 ++++++++-
 .../pci/controller/mobiveil/pcie-mobiveil.h   |  3 ++
 3 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/mobiveil/pci-layerscape-gen4.c b/drivers/pci/controller/mobiveil/pci-layerscape-gen4.c
index 174cbcac4059..d2c5dbbd5e3c 100644
--- a/drivers/pci/controller/mobiveil/pci-layerscape-gen4.c
+++ b/drivers/pci/controller/mobiveil/pci-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		(31)
@@ -41,6 +46,7 @@ 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)
@@ -76,6 +82,15 @@ static bool ls_pcie_g4_is_bridge(struct ls_pcie_g4 *pcie)
 	return header_type == PCI_HEADER_TYPE_BRIDGE;
 }
 
+static int ls_pcie_g4_host_init(struct mobiveil_pcie *pci)
+{
+	struct ls_pcie_g4 *pcie = to_ls_pcie_g4(pci);
+
+	pcie->rev = 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);
@@ -188,12 +203,34 @@ static void ls_pcie_g4_reset(struct work_struct *work)
 	ls_pcie_g4_reinit_hw(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)
diff --git a/drivers/pci/controller/mobiveil/pcie-mobiveil-host.c b/drivers/pci/controller/mobiveil/pcie-mobiveil-host.c
index c85f00d3cfcf..70f64cdde37f 100644
--- a/drivers/pci/controller/mobiveil/pcie-mobiveil-host.c
+++ b/drivers/pci/controller/mobiveil/pcie-mobiveil-host.c
@@ -79,9 +79,20 @@ static void __iomem *mobiveil_pcie_map_bus(struct pci_bus *bus,
 	return pcie->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 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,
 };
 
@@ -309,6 +320,10 @@ int mobiveil_host_init(struct mobiveil_pcie *pcie, bool reinit)
 	value |= (PCI_CLASS_BRIDGE_PCI << 16);
 	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;
 }
 
diff --git a/drivers/pci/controller/mobiveil/pcie-mobiveil.h b/drivers/pci/controller/mobiveil/pcie-mobiveil.h
index 0ccd6cee5f8f..ab43de5e4b2b 100644
--- a/drivers/pci/controller/mobiveil/pcie-mobiveil.h
+++ b/drivers/pci/controller/mobiveil/pcie-mobiveil.h
@@ -145,6 +145,8 @@ struct mobiveil_msi {			/* MSI information */
 
 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 root_port {
@@ -160,6 +162,7 @@ struct root_port {
 
 struct mobiveil_pab_ops {
 	int (*link_up)(struct mobiveil_pcie *pcie);
+	int (*host_init)(struct mobiveil_pcie *pcie);
 };
 
 struct mobiveil_pcie {
-- 
2.17.1

[PATCHv2 2/2] PCI: mobiveil: ls_pcie_g4: add Workaround for A-011451

[Z.q. Hou]

From: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>

When LX2 PCIe controller is sending multiple split completions and
ACK latency expires indicating that ACK should be send at priority.
But because of large number of split completions and FC update DLLP,
the controller does not give priority to ACK transmission. This
results into ACK latency timer timeout error at the link partner and
the pending TLPs are replayed by the link partner again.

Workaround:
1. Reduce the ACK latency timeout value to a very small value.
2. Restrict the number of completions from the LX2 PCIe controller
   to 1, by changing the Max Read Request Size (MRRS) of link partner
   to the same value as Max Packet size (MPS).

This patch implemented part 1, the part 2 can be set by kernel parameter
'pci=pcie_bus_perf'

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>
---
V2:
 - Only apply the workaround for Rev1.0.

 .../pci/controller/mobiveil/pci-layerscape-gen4.c | 15 +++++++++++++++
 drivers/pci/controller/mobiveil/pcie-mobiveil.h   |  4 ++++
 2 files changed, 19 insertions(+)

diff --git a/drivers/pci/controller/mobiveil/pci-layerscape-gen4.c b/drivers/pci/controller/mobiveil/pci-layerscape-gen4.c
index d2c5dbbd5e3c..20ce146788ca 100644
--- a/drivers/pci/controller/mobiveil/pci-layerscape-gen4.c
+++ b/drivers/pci/controller/mobiveil/pci-layerscape-gen4.c
@@ -82,12 +82,27 @@ static bool ls_pcie_g4_is_bridge(struct ls_pcie_g4 *pcie)
 	return header_type == PCI_HEADER_TYPE_BRIDGE;
 }
 
+static void workaround_A011451(struct ls_pcie_g4 *pcie)
+{
+	struct mobiveil_pcie *mv_pci = pcie->pci;
+	u32 val;
+
+	/* Set ACK latency timeout */
+	val = csr_readl(mv_pci, GPEX_ACK_REPLAY_TO);
+	val &= ~(ACK_LAT_TO_VAL_MASK << ACK_LAT_TO_VAL_SHIFT);
+	val |= (4 << ACK_LAT_TO_VAL_SHIFT);
+	csr_writel(mv_pci, val, GPEX_ACK_REPLAY_TO);
+}
+
 static int ls_pcie_g4_host_init(struct mobiveil_pcie *pci)
 {
 	struct ls_pcie_g4 *pcie = to_ls_pcie_g4(pci);
 
 	pcie->rev = csr_readb(pci, PCI_REVISION_ID);
 
+	if (pcie->rev == REV_1_0)
+		workaround_A011451(pcie);
+
 	return 0;
 }
 
diff --git a/drivers/pci/controller/mobiveil/pcie-mobiveil.h b/drivers/pci/controller/mobiveil/pcie-mobiveil.h
index ab43de5e4b2b..f0e2e4ae09b5 100644
--- a/drivers/pci/controller/mobiveil/pcie-mobiveil.h
+++ b/drivers/pci/controller/mobiveil/pcie-mobiveil.h
@@ -85,6 +85,10 @@
 #define PAB_AXI_AMAP_PEX_WIN_H(win)	PAB_REG_ADDR(0x0bac, win)
 #define PAB_INTP_AXI_PIO_CLASS		0x474
 
+#define GPEX_ACK_REPLAY_TO		0x438
+#define  ACK_LAT_TO_VAL_MASK		0x1fff
+#define  ACK_LAT_TO_VAL_SHIFT		0
+
 #define PAB_PEX_AMAP_CTRL(win)		PAB_REG_ADDR(0x4ba0, win)
 #define  AMAP_CTRL_EN_SHIFT		0
 #define  AMAP_CTRL_TYPE_SHIFT		1
-- 
2.17.1