Subject: [PATCH v11] PCI: Xilinx-NWL-PCIe: Added support for Xilinx NWL PCIe Host Controller

From: [email-masked] (Bjorn Helgaas)
Date: Wed, 9 Dec 2015 17:19:21 -0600

[+cc Michal, Paul, Thierry, Stephen, Alexandre (see irq_dispose_mapping questions below)]

On Sun, Nov 29, 2015 at 05:33:53PM +0530, Bharat Kumar Gogada wrote:
> Adding PCIe Root Port driver for Xilinx PCIe NWL bridge IP.
> 
> Signed-off-by: Bharat Kumar Gogada <[email-masked]>
> Signed-off-by: Ravi Kiran Gummaluri <[email-masked]>
> Acked-by: Rob Herring <[email-masked]>

This needs either a MAINTAINERS update or an ack from Michal (whose
MAINTAINERS entry matches anything containing "xilinx").

> ---
> Changes for v11:
> -> Changed data types of bridge, pcie controller and ecam base address
> -> Added programming of E_BREG_BASE_HI, E_ECAM_BASE_HI registers
> -> Removed MSI_ADDRESS macro, and using value from device tree
> -> Removed unneccessary type casting in nwl_pcie_bridge_init function.
> -> Removed mdelay and using msleep in nwl_pcie_bridge_init function.
> ---
>  .../devicetree/bindings/pci/xilinx-nwl-pcie.txt    |   68 ++
>  drivers/pci/host/Kconfig                           |   10 +
>  drivers/pci/host/Makefile                          |    1 +
>  drivers/pci/host/pcie-xilinx-nwl.c                 | 1072 ++++++++++++++++++++
>  4 files changed, 1151 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pci/xilinx-nwl-pcie.txt
>  create mode 100644 drivers/pci/host/pcie-xilinx-nwl.c
> 
> diff --git a/Documentation/devicetree/bindings/pci/xilinx-nwl-pcie.txt b/Documentation/devicetree/bindings/pci/xilinx-nwl-pcie.txt
> new file mode 100644
> index 0000000..3b2a9ad
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pci/xilinx-nwl-pcie.txt
> @@ -0,0 +1,68 @@
> +* Xilinx NWL PCIe Root Port Bridge DT description
> +
> +Required properties:
> +- compatible: Should contain "xlnx,nwl-pcie-2.11"
> +- #address-cells: Address representation for root ports, set to <3>
> +- #size-cells: Size representation for root ports, set to <2>
> +- #interrupt-cells: specifies the number of cells needed to encode an
> +	interrupt source. The value must be 1.
> +- reg: Should contain Bridge, PCIe Controller registers location,
> +	configuration sapce, and length
> +- reg-names: Must include the following entries:
> +	"breg": bridge registers
> +	"pcireg": PCIe controller registers
> +	"cfg": configuration space region
> +- device_type: must be "pci"
> +- interrupts: Should contain NWL PCIe interrupt
> +- interrupt-names: Must include the following entries:
> +	"msi1, msi0": interrupt asserted when msi is received
> +	"intx": interrupt that is asserted when an legacy interrupt is received
> +	"misc": interrupt asserted when miscellaneous is received
> +- interrupt-map-mask and interrupt-map: standard PCI properties to define the
> +	mapping of the PCI interface to interrupt numbers.
> +- ranges: ranges for the PCI memory regions (I/O space region is not
> +	supported by hardware)
> +	Please refer to the standard PCI bus binding document for a more
> +	detailed explanation
> +- msi-controller: indicates that this is MSI controller node
> +- msi-parent:  MSI parent of the root complex itself
> +- legacy-interrupt-controller: Interrupt controller device node for Legacy interrupts
> +	- interrupt-controller: identifies the node as an interrupt controller
> +	- #interrupt-cells: should be set to 1
> +	- #address-cells: specifies the number of cells needed to encode an
> +		address. The value must be 0.
> +
> +
> +Example:
> +++++++++
> +
> +nwl_pcie: pcie at fd0e0000 {
> +	#address-cells = <3>;
> +	#size-cells = <2>;
> +	compatible = "xlnx,nwl-pcie-2.11";
> +	#interrupt-cells = <1>;
> +	msi-controller;
> +	device_type = "pci";
> +	interrupt-parent = <&gic>;
> +	interrupts = <0 114 4>, <0 115 4>, <0 116 4>, <0 117 4>, <0 118 4>;
> +	interrupt-names = "msi0", "msi1", "intx", "dummy", "misc";
> +	interrupt-map-mask = <0x0 0x0 0x0 0x7>;
> +	interrupt-map = <0x0 0x0 0x0 0x1 &pcie_intc 0x1>,
> +			<0x0 0x0 0x0 0x2 &pcie_intc 0x2>,
> +			<0x0 0x0 0x0 0x3 &pcie_intc 0x3>,
> +			<0x0 0x0 0x0 0x4 &pcie_intc 0x4>;
> +
> +	msi-parent = <&nwl_pcie>;
> +	reg = <0x0 0xfd0e0000 0x1000>,
> +	      <0x0 0xfd480000 0x1000>,
> +	      <0x0 0xe0000000 0x1000000>;
> +	reg-names = "breg", "pcireg", "cfg";
> +	ranges = <0x02000000 0x00000000 0xe1000000 0x00000000 0xe1000000 0 0x0f000000>;
> +
> +	pcie_intc: legacy-interrupt-controller {
> +		interrupt-controller;
> +		#address-cells = <0>;
> +		#interrupt-cells = <1>;
> +	};
> +
> +};
> diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
> index d5e58ba..24cbcba 100644
> --- a/drivers/pci/host/Kconfig
> +++ b/drivers/pci/host/Kconfig
> @@ -15,6 +15,16 @@ config PCI_MVEBU
>  	depends on ARCH_MVEBU || ARCH_DOVE
>  	depends on OF
>  
> +config PCIE_XILINX_NWL
> +	bool "NWL PCIe Core"
> +	depends on ARCH_ZYNQMP
> +	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
> +	help
> +	 Say 'Y' here if you want kernel to support for Xilinx
> +	 NWL PCIe controller. The controller can act as Root Port
> +	 or End Point. The current option selection will only
> +	 support root port enabling.
> +
>  config PCIE_DW
>  	bool
>  
> diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
> index 140d66f..6a56df7 100644
> --- a/drivers/pci/host/Makefile
> +++ b/drivers/pci/host/Makefile
> @@ -10,6 +10,7 @@ obj-$(CONFIG_PCI_HOST_GENERIC) += pci-host-generic.o
>  obj-$(CONFIG_PCIE_SPEAR13XX) += pcie-spear13xx.o
>  obj-$(CONFIG_PCI_KEYSTONE) += pci-keystone-dw.o pci-keystone.o
>  obj-$(CONFIG_PCIE_XILINX) += pcie-xilinx.o
> +obj-$(CONFIG_PCIE_XILINX_NWL) += pcie-xilinx-nwl.o
>  obj-$(CONFIG_PCI_XGENE) += pci-xgene.o
>  obj-$(CONFIG_PCI_XGENE_MSI) += pci-xgene-msi.o
>  obj-$(CONFIG_PCI_LAYERSCAPE) += pci-layerscape.o
> diff --git a/drivers/pci/host/pcie-xilinx-nwl.c b/drivers/pci/host/pcie-xilinx-nwl.c
> new file mode 100644
> index 0000000..024d0c0
> --- /dev/null
> +++ b/drivers/pci/host/pcie-xilinx-nwl.c
> @@ -0,0 +1,1072 @@
> +/*
> + * PCIe host controller driver for NWL PCIe Bridge
> + * Based on pcie-xilinx.c, pci-tegra.c
> + *
> + * (C) Copyright 2014 - 2015, Xilinx, Inc.
> + *
> + * This program is free software: you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation, either version 2 of the License, or
> + * (at your option) any later version.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/irqdomain.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/msi.h>
> +#include <linux/of_address.h>
> +#include <linux/of_pci.h>
> +#include <linux/of_platform.h>
> +#include <linux/of_irq.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +#include <linux/irqchip/chained_irq.h>
> +
> +/* Bridge core config registers */
> +#define BRCFG_PCIE_RX0			0x00000000
> +#define BRCFG_PCIE_RX1			0x00000004
> +#define BRCFG_AXI_MASTER		0x00000008
> +#define BRCFG_PCIE_TX			0x0000000C
> +#define BRCFG_INTERRUPT			0x00000010
> +#define BRCFG_RAM_DISABLE0		0x00000014
> +#define BRCFG_RAM_DISABLE1		0x00000018
> +#define BRCFG_PCIE_RELAXED_ORDER	0x0000001C
> +#define BRCFG_PCIE_RX_MSG_FILTER	0x00000020
> +
> +/* Attribute registers */
> +#define NWL_ATTRIB_100			0x00000190
> +
> +/* Egress - Bridge translation registers */
> +#define E_BREG_CAPABILITIES		0x00000200
> +#define E_BREG_STATUS			0x00000204
> +#define E_BREG_CONTROL			0x00000208
> +#define E_BREG_BASE_LO			0x00000210
> +#define E_BREG_BASE_HI			0x00000214
> +#define E_ECAM_CAPABILITIES		0x00000220
> +#define E_ECAM_STATUS			0x00000224
> +#define E_ECAM_CONTROL			0x00000228
> +#define E_ECAM_BASE_LO			0x00000230
> +#define E_ECAM_BASE_HI			0x00000234
> +
> +/* Ingress - address translations */
> +#define I_MSII_CAPABILITIES		0x00000300
> +#define I_MSII_CONTROL			0x00000308
> +#define I_MSII_BASE_LO			0x00000310
> +#define I_MSII_BASE_HI			0x00000314
> +
> +#define I_ISUB_CONTROL			0x000003E8
> +#define SET_ISUB_CONTROL		BIT(0)
> +/* Rxed msg fifo  - Interrupt status registers */
> +#define MSGF_MISC_STATUS		0x00000400
> +#define MSGF_MISC_MASK			0x00000404
> +#define MSGF_LEG_STATUS			0x00000420
> +#define MSGF_LEG_MASK			0x00000424
> +#define MSGF_MSI_STATUS_LO		0x00000440
> +#define MSGF_MSI_STATUS_HI		0x00000444
> +#define MSGF_MSI_MASK_LO		0x00000448
> +#define MSGF_MSI_MASK_HI		0x0000044C
> +#define MSGF_RX_FIFO_POP		0x00000484
> +#define MSGF_RX_FIFO_TYPE		0x00000488
> +#define MSGF_RX_FIFO_ADDRLO		0x00000490
> +#define MSGF_RX_FIFO_ADDRHI		0x00000494
> +#define MSGF_RX_FIFO_DATA		0x00000498
> +
> +/* Msg filter mask bits */
> +#define CFG_ENABLE_PM_MSG_FWD		BIT(1)
> +#define CFG_ENABLE_INT_MSG_FWD		BIT(2)
> +#define CFG_ENABLE_ERR_MSG_FWD		BIT(3)
> +#define CFG_ENABLE_SLT_MSG_FWD		BIT(5)
> +#define CFG_ENABLE_VEN_MSG_FWD		BIT(7)
> +#define CFG_ENABLE_OTH_MSG_FWD		BIT(13)
> +#define CFG_ENABLE_VEN_MSG_EN		BIT(14)
> +#define CFG_ENABLE_VEN_MSG_VEN_INV	BIT(15)
> +#define CFG_ENABLE_VEN_MSG_VEN_ID	GENMASK(31, 16)
> +#define CFG_ENABLE_MSG_FILTER_MASK	(CFG_ENABLE_PM_MSG_FWD | \
> +					CFG_ENABLE_INT_MSG_FWD | \
> +					CFG_ENABLE_ERR_MSG_FWD | \
> +					CFG_ENABLE_SLT_MSG_FWD | \
> +					CFG_ENABLE_VEN_MSG_FWD | \
> +					CFG_ENABLE_OTH_MSG_FWD | \
> +					CFG_ENABLE_VEN_MSG_EN | \
> +					CFG_ENABLE_VEN_MSG_VEN_INV | \
> +					CFG_ENABLE_VEN_MSG_VEN_ID)
> +
> +/* Misc interrupt status mask bits */
> +#define MSGF_MISC_SR_RXMSG_AVAIL	BIT(0)
> +#define MSGF_MISC_SR_RXMSG_OVER		BIT(1)
> +#define MSGF_MISC_SR_SLAVE_ERR		BIT(4)
> +#define MSGF_MISC_SR_MASTER_ERR		BIT(5)
> +#define MSGF_MISC_SR_I_ADDR_ERR		BIT(6)
> +#define MSGF_MISC_SR_E_ADDR_ERR		BIT(7)
> +#define MSGF_MISC_SR_UR_DETECT          BIT(20)
> +
> +#define MSGF_MISC_SR_PCIE_CORE		GENMASK(18, 16)
> +#define MSGF_MISC_SR_PCIE_CORE_ERR	GENMASK(31, 22)
> +
> +#define MSGF_MISC_SR_MASKALL		(MSGF_MISC_SR_RXMSG_AVAIL | \
> +					MSGF_MISC_SR_RXMSG_OVER | \
> +					MSGF_MISC_SR_SLAVE_ERR | \
> +					MSGF_MISC_SR_MASTER_ERR | \
> +					MSGF_MISC_SR_I_ADDR_ERR | \
> +					MSGF_MISC_SR_E_ADDR_ERR | \
> +					MSGF_MISC_SR_UR_DETECT | \
> +					MSGF_MISC_SR_PCIE_CORE | \
> +					MSGF_MISC_SR_PCIE_CORE_ERR)
> +
> +/* Message rx fifo type mask bits */
> +#define MSGF_RX_FIFO_TYPE_MSI	(1)
> +#define MSGF_RX_FIFO_TYPE_TYPE	GENMASK(1, 0)
> +
> +/* Legacy interrupt status mask bits */
> +#define MSGF_LEG_SR_INTA		BIT(0)
> +#define MSGF_LEG_SR_INTB		BIT(1)
> +#define MSGF_LEG_SR_INTC		BIT(2)
> +#define MSGF_LEG_SR_INTD		BIT(3)
> +#define MSGF_LEG_SR_MASKALL		(MSGF_LEG_SR_INTA | MSGF_LEG_SR_INTB | \
> +					MSGF_LEG_SR_INTC | MSGF_LEG_SR_INTD)
> +
> +/* MSI interrupt status mask bits */
> +#define MSGF_MSI_SR_LO_MASK		BIT(0)
> +#define MSGF_MSI_SR_HI_MASK		BIT(0)
> +
> +#define MSII_PRESENT			BIT(0)
> +#define MSII_ENABLE			BIT(0)
> +#define MSII_STATUS_ENABLE		BIT(15)
> +
> +/* Bridge config interrupt mask */
> +#define BRCFG_INTERRUPT_MASK		BIT(0)
> +#define BREG_PRESENT			BIT(0)
> +#define BREG_ENABLE			BIT(0)
> +#define BREG_ENABLE_FORCE		BIT(1)
> +
> +/* E_ECAM status mask bits */
> +#define E_ECAM_PRESENT			BIT(0)
> +#define E_ECAM_SR_WR_PEND		BIT(16)
> +#define E_ECAM_SR_RD_PEND		BIT(0)
> +#define E_ECAM_SR_MASKALL		(E_ECAM_SR_WR_PEND | E_ECAM_SR_RD_PEND)
> +#define E_ECAM_CR_ENABLE		BIT(0)
> +#define E_ECAM_SIZE_LOC			GENMASK(20, 16)
> +#define E_ECAM_SIZE_SHIFT		16
> +#define ECAM_BUS_LOC_SHIFT		20
> +#define ECAM_DEV_LOC_SHIFT		12
> +#define NWL_ECAM_VALUE_DEFAULT		12
> +#define NWL_ECAM_SIZE_MIN		4096
> +
> +#define ATTR_UPSTREAM_FACING		BIT(6)
> +#define CFG_DMA_REG_BAR			GENMASK(2, 0)
> +
> +/* msgf_rx_fifo_pop bits */
> +#define MSGF_RX_FIFO_POP_POP	BIT(0)
> +
> +#define INT_PCI_MSI_NR			(2 * 32)
> +
> +/* Readin the PS_LINKUP */
> +#define PS_LINKUP_OFFSET			0x00000238
> +#define PCIE_PHY_LINKUP_BIT			BIT(0)
> +#define PHY_RDY_LINKUP_BIT			BIT(1)
> +#define PCIE_USER_LINKUP			0
> +#define PHY_RDY_LINKUP				1
> +#define LINKUP_ITER_CHECK			5
> +
> +/* PCIE Message Request */
> +#define TX_PCIE_MSG				0x00000620
> +#define TX_PCIE_MSG_CNTL			0x00000004
> +#define TX_PCIE_MSG_SPEC_LO			0x00000008
> +#define TX_PCIE_MSG_SPEC_HI			0x0000000C
> +#define TX_PCIE_MSG_DATA			0x00000010
> +
> +#define MSG_BUSY_BIT				BIT(8)
> +#define MSG_EXECUTE_BIT				BIT(0)
> +#define MSG_DONE_BIT				BIT(16)
> +#define MSG_DONE_STATUS_BIT			(BIT(25) | BIT(24))
> +#define RANDOM_DIGIT				0x11223344
> +#define PATTRN_SSLP_TLP				0x01005074
> +
> +#define EXP_CAP_BASE				0x60
> +
> +/* SSPL ERROR */
> +#define SLVERR					0x02
> +#define DECERR					0x03
> +
> +struct nwl_msi {			/* MSI information */
> +	struct irq_domain *msi_domain;
> +	unsigned long *bitmap;
> +	struct irq_domain *dev_domain;
> +	struct mutex lock;		/* protect bitmap variable */
> +	int irq_msi0;
> +	int irq_msi1;
> +};
> +
> +struct nwl_pcie {
> +	struct device *dev;
> +	void __iomem *breg_base;
> +	void __iomem *pcireg_base;
> +	void __iomem *ecam_base;
> +	phys_addr_t phys_breg_base;	/* Physical Bridge Register Base */
> +	phys_addr_t phys_pcie_reg_base;	/* Physical PCIe Controller Base */
> +	phys_addr_t phys_ecam_base;	/* Physical Configuration Base */
> +	u32 breg_size;
> +	u32 pcie_reg_size;
> +	u32 ecam_size;
> +	int irq_intx;
> +	int irq_misc;
> +	u32 ecam_value;
> +	u8 last_busno;
> +	u8 root_busno;
> +	u8 link_up;
> +	struct nwl_msi msi;
> +	struct irq_domain *legacy_irq_domain;
> +};
> +
> +static inline u32 nwl_bridge_readl(struct nwl_pcie *pcie, u32 off)
> +{
> +	return readl(pcie->breg_base + off);
> +}
> +
> +static inline void nwl_bridge_writel(struct nwl_pcie *pcie, u32 val, u32 off)
> +{
> +	writel(val, pcie->breg_base + off);
> +}
> +
> +static inline bool nwl_pcie_link_up(struct nwl_pcie *pcie, u32 check_link_up)
> +{
> +	unsigned int status = -EINVAL;
> +
> +	if (check_link_up == PCIE_USER_LINKUP)
> +		status = (readl(pcie->pcireg_base + PS_LINKUP_OFFSET) &
> +			  PCIE_PHY_LINKUP_BIT) ? 1 : 0;
> +	else if (check_link_up == PHY_RDY_LINKUP)
> +		status = (readl(pcie->pcireg_base + PS_LINKUP_OFFSET) &
> +			  PHY_RDY_LINKUP_BIT) ? 1 : 0;
> +	return status;

It's a bit sloppy here to return 0, 1, or -EINVAL from a function declared
to return "bool".  A bool function should return "true" or "false".

I think the best thing is to split this into two functions:

  static bool nwl_pcie_link_up(struct nwl_pcie *pcie)
  {
    if (readl(pcie->pcireg_base + PS_LINKUP_OFFSET) & PCIE_PHY_LINKUP_BIT)
      return true;
    return false;
  }

  static bool nwl_phy_link_up(struct nwl_pcie *pcie)
  {
    if (readl(pcie->pcireg_base + PS_LINKUP_OFFSET) & PHY_RDY_LINKUP_BIT)
      return true;
    return false;
  }

Then there's no possibility of a caller passing an invalid
"check_link_up" argument, so you don't have to worry about an -EINVAL
return.

> +}
> +
> +static bool nwl_pcie_valid_device(struct pci_bus *bus, unsigned int devfn)
> +{
> +	struct nwl_pcie *pcie = bus->sysdata;
> +
> +	/* Check link,before accessing downstream ports */
> +	if (bus->number != pcie->root_busno) {
> +		if (!nwl_pcie_link_up(pcie, PCIE_USER_LINKUP))
> +			return false;
> +	}
> +
> +	/* Only one device down on each root port */
> +	if (bus->number == pcie->root_busno && devfn > 0)
> +		return false;
> +
> +	/*
> +	 * Do not read more than one device on the bus directly attached
> +	 * to root port.
> +	 */
> +	if (bus->primary == pcie->root_busno && devfn > 0)

Why is this?  Do you have some restriction on the PCIe topology below the
Root Port?  If there's a spec-compliant link coming from the Root Port, it
seems like any legal PCIe device could be attached, including a
multifunction device.

> +		return false;
> +
> +	return true;
> +}
> +
> +/**
> + * nwl_pcie_get_config_base - Get configuration base
> + *
> + * @bus: Bus structure of current bus
> + * @devfn: Device/function
> + * @where: Offset from base
> + *
> + * Return: Base address of the configuration space needed to be
> + *	   accessed.
> + */
> +static void __iomem *nwl_pcie_get_config_base(struct pci_bus *bus,
> +						 unsigned int devfn,
> +						 int where)
> +{
> +	struct nwl_pcie *pcie = bus->sysdata;
> +	int relbus;
> +
> +	if (!nwl_pcie_valid_device(bus, devfn))
> +		return NULL;
> +
> +	relbus = (bus->number << ECAM_BUS_LOC_SHIFT) |
> +			(devfn << ECAM_DEV_LOC_SHIFT);
> +
> +	return pcie->ecam_base + relbus + where;
> +}
> +
> +/**
> + * nwl_setup_sspl - Set Slot Power limit
> + *
> + * @pcie: PCIe port information
> + */
> +static int nwl_setup_sspl(struct nwl_pcie *pcie)

This function needs a little explanation because it doesn't really make
any sense when compared with the PCIe spec.  The spec says the Slot Power
Limit Value is HwInit, which means it's supposed to be initialized by
firmware or hardware, and it should be read-only by the time we get here.
I think the value there should reflect parameters of the hardware design;
we wouldn't want a user to write an arbitrary limit that would tell a card
it can pull more power than the slot can supply.

But I saw another driver recently (pcie-snpsdev.c) that's doing something
similar, so there must be something else going on here.  In any case, a
comment here about exactly *what* is going on would be much appreciated.

> +{
> +	unsigned int status;
> +	int retval = 0;
> +
> +	do {
> +		status = nwl_bridge_readl(pcie, TX_PCIE_MSG) & MSG_BUSY_BIT;
> +		if (!status) {
> +			/*
> +			 * Generate the TLP message for a single EP
> +			 */
> +			nwl_bridge_writel(pcie, 0x0,
> +					  TX_PCIE_MSG + TX_PCIE_MSG_CNTL);
> +			nwl_bridge_writel(pcie, 0x0,
> +					  TX_PCIE_MSG + TX_PCIE_MSG_SPEC_LO);
> +			nwl_bridge_writel(pcie, 0x0,
> +					  TX_PCIE_MSG + TX_PCIE_MSG_SPEC_HI);
> +			nwl_bridge_writel(pcie, 0x0,
> +					  TX_PCIE_MSG + TX_PCIE_MSG_DATA);
> +			/* Pattern to generate SSLP TLP */
> +			nwl_bridge_writel(pcie, PATTRN_SSLP_TLP,
> +					  TX_PCIE_MSG + TX_PCIE_MSG_CNTL);
> +			nwl_bridge_writel(pcie, RANDOM_DIGIT,
> +					  TX_PCIE_MSG + TX_PCIE_MSG_DATA);
> +			nwl_bridge_writel(pcie, nwl_bridge_readl(pcie,
> +					  TX_PCIE_MSG) | 0x1, TX_PCIE_MSG);
> +			mdelay(2);

Arnd suggested a sleep instead of delay here, but I didn't see a
response.  See http://lkml.kernel.org/r/2677327.lnRZhqx5GI at wuerfel

> +			status = nwl_bridge_readl(pcie, TX_PCIE_MSG)
> +						  & MSG_DONE_BIT;
> +			if (status) {
> +				status = nwl_bridge_readl(pcie, TX_PCIE_MSG)
> +						  & MSG_DONE_STATUS_BIT;
> +				if (status == SLVERR) {
> +					dev_err(pcie->dev, "AXI slave error");
> +					retval = SLVERR;
> +				} else if (status == DECERR) {
> +					dev_err(pcie->dev, "AXI Decode error");
> +					retval = DECERR;
> +				}

I think both these cases (SLVERR and DECERR) are impossible:

  #define MSG_DONE_STATUS_BIT                     (BIT(25) | BIT(24))
  #define SLVERR                                  0x02
  #define DECERR                                  0x03

MSG_DONE_STATUS_BIT is 0x3000000, so after masking status with it, the
result can never be 0x02 or 0x03.

> +			} else {
> +				retval = 1;
> +			}

You only set "retval = 1" here in the case when "status == 0", which means
you'll exit the loop, so this would be slightly simpler as:

  status = nwl_bridge_readl(pcie, TX_PCIE_MSG) & MSG_DONE_BIT;
  if (!status)
    return 1;

  status = nwl_bridge_readl(pcie, TX_PCIE_MSG) & MSG_DONE_STATUS_BIT;
  ...

It's not clear to me whether you need to re-read TX_PCIE_MSG here.

> +		}
> +	} while (status);
> +
> +	return retval;
> +}
> +
> +/**
> + * nwl_nwl_readl_config - Read configuration space
> + *
> + * @bus: Bus structure of current bus
> + * @devfn: Device/function
> + * @where: Offset from base
> + * @size: Byte/word/dword
> + * @val: Value to be read
> + *
> + * Return: PCIBIOS_SUCCESSFUL on success
> + *	   PCIBIOS_DEVICE_NOT_FOUND on failure.
> + */
> +static int nwl_nwl_readl_config(struct pci_bus *bus,
> +				unsigned int devfn,
> +				int where,
> +				int size,
> +				u32 *val)
> +{
> +	void __iomem *addr;
> +
> +	addr = nwl_pcie_get_config_base(bus, devfn, where);
> +	if (!addr) {
> +		*val = ~0;
> +		return PCIBIOS_DEVICE_NOT_FOUND;
> +	}
> +
> +	switch (size) {
> +	case 1:
> +		*val = readb(addr);
> +		break;
> +	case 2:
> +		*val = readw(addr);
> +		break;
> +	default:
> +		*val = readl(addr);
> +		break;
> +	}
> +	return PCIBIOS_SUCCESSFUL;
> +}
> +
> +/**
> + * nwl_nwl_writel_config - Write configuration space
> + *
> + * @bus: Bus structure of current bus
> + * @devfn: Device/function
> + * @where: Offset from base
> + * @size: Byte/word/dword
> + * @val: Value to be written to device
> + *
> + * Return: PCIBIOS_SUCCESSFUL on success,
> + *	   PCIBIOS_DEVICE_NOT_FOUND on failure.
> + */
> +static int nwl_nwl_writel_config(struct pci_bus *bus,
> +				unsigned int devfn,
> +				int where,
> +				int size,
> +				u32 val)
> +{
> +	void __iomem *addr;
> +	int retval;
> +	struct nwl_pcie *pcie = bus->sysdata;
> +
> +	addr = nwl_pcie_get_config_base(bus, devfn, where);
> +	if (!addr)
> +		return PCIBIOS_DEVICE_NOT_FOUND;
> +
> +	switch (size) {
> +	case 1:
> +		writeb(val, addr);
> +		break;
> +	case 2:
> +		writew(val, addr);
> +		break;
> +	default:
> +		writel(val, addr);
> +		break;
> +	}
> +	if (addr == (pcie->ecam_base + EXP_CAP_BASE + PCI_EXP_SLTCAP)) {
> +		retval = nwl_setup_sspl(pcie);
> +		if (retval)
> +			return PCIBIOS_SET_FAILED;
> +	}
> +
> +	return PCIBIOS_SUCCESSFUL;
> +}
> +
> +/* PCIe operations */
> +static struct pci_ops nwl_pcie_ops = {
> +	.read  = nwl_nwl_readl_config,
> +	.write = nwl_nwl_writel_config,
> +};
> +
> +static irqreturn_t nwl_pcie_misc_handler(int irq, void *data)
> +{
> +	struct nwl_pcie *pcie = data;
> +	u32 misc_stat;
> +
> +	/* Checking for misc interrupts */
> +	misc_stat = nwl_bridge_readl(pcie, MSGF_MISC_STATUS) &
> +				     MSGF_MISC_SR_MASKALL;
> +	if (!misc_stat)
> +		return IRQ_NONE;
> +
> +	if (misc_stat & MSGF_MISC_SR_RXMSG_OVER)
> +		dev_err(pcie->dev, "Received Message FIFO Overflow\n");
> +
> +	if (misc_stat & MSGF_MISC_SR_SLAVE_ERR)
> +		dev_err(pcie->dev, "Slave error\n");
> +
> +	if (misc_stat & MSGF_MISC_SR_MASTER_ERR)
> +		dev_err(pcie->dev, "Master error\n");
> +
> +	if (misc_stat & MSGF_MISC_SR_I_ADDR_ERR)
> +		dev_err(pcie->dev,
> +			"In Misc Ingress address translation error\n");
> +
> +	if (misc_stat & MSGF_MISC_SR_E_ADDR_ERR)
> +		dev_err(pcie->dev,
> +			"In Misc Egress address translation error\n");
> +
> +	if (misc_stat & MSGF_MISC_SR_PCIE_CORE_ERR)
> +		dev_err(pcie->dev, "PCIe Core error\n");
> +
> +	/* Clear misc interrupt status */
> +	nwl_bridge_writel(pcie, misc_stat, MSGF_MISC_STATUS);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static void nwl_pcie_leg_handler(struct irq_desc *desc)
> +{
> +	struct irq_chip *chip = irq_desc_get_chip(desc);
> +	struct nwl_pcie *pcie;
> +	unsigned long status;
> +	u32 bit;
> +	u32 virq;
> +
> +	chained_irq_enter(chip, desc);
> +	pcie = irq_desc_get_handler_data(desc);
> +
> +	while ((status = nwl_bridge_readl(pcie, MSGF_LEG_STATUS) &
> +				MSGF_LEG_SR_MASKALL) != 0) {
> +		for_each_set_bit(bit, &status, 4) {
> +
> +			virq = irq_find_mapping(pcie->legacy_irq_domain,
> +						bit + 1);
> +			if (virq)
> +				generic_handle_irq(virq);
> +		}
> +	}
> +
> +	chained_irq_exit(chip, desc);
> +}
> +
> +static void nwl_pcie_handle_msi_irq(struct nwl_pcie *pcie, u32 status_reg)
> +{
> +	struct nwl_msi *msi;
> +	unsigned long status;
> +	u32 bit;
> +	u32 virq;
> +
> +	msi = &pcie->msi;
> +
> +	while ((status = nwl_bridge_readl(pcie, status_reg)) != 0) {
> +		for_each_set_bit(bit, &status, 32) {
> +			nwl_bridge_writel(pcie, 1 << bit, status_reg);
> +			virq = irq_find_mapping(msi->dev_domain, bit);
> +			if (virq)
> +				generic_handle_irq(virq);
> +		}
> +	}
> +}
> +
> +static void nwl_pcie_msi_handler_high(struct irq_desc *desc)
> +{
> +	struct irq_chip *chip = irq_desc_get_chip(desc);
> +	struct nwl_pcie *pcie;
> +
> +	chained_irq_enter(chip, desc);
> +	pcie = irq_desc_get_handler_data(desc);
> +	nwl_pcie_handle_msi_irq(pcie, MSGF_MSI_STATUS_HI);
> +
> +	chained_irq_exit(chip, desc);
> +}
> +
> +static void nwl_pcie_msi_handler_low(struct irq_desc *desc)
> +{
> +	struct irq_chip *chip = irq_desc_get_chip(desc);
> +	struct nwl_pcie *pcie;
> +
> +	chained_irq_enter(chip, desc);
> +	pcie = irq_desc_get_handler_data(desc);
> +	nwl_pcie_handle_msi_irq(pcie, MSGF_MSI_STATUS_LO);
> +
> +	chained_irq_exit(chip, desc);
> +}
> +
> +static int nwl_legacy_map(struct irq_domain *domain, unsigned int irq,
> +				irq_hw_number_t hwirq)
> +{
> +	irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
> +	irq_set_chip_data(irq, domain->host_data);
> +
> +	return 0;
> +}
> +
> +static const struct irq_domain_ops legacy_domain_ops = {
> +	.map = nwl_legacy_map,
> +};
> +
> +#ifdef CONFIG_PCI_MSI
> +static struct irq_chip nwl_msi_irq_chip = {
> +	.name = "nwl_pcie:msi",
> +	.irq_enable = unmask_msi_irq,
> +	.irq_disable = mask_msi_irq,
> +	.irq_mask = mask_msi_irq,
> +	.irq_unmask = unmask_msi_irq,
> +
> +};
> +
> +static struct msi_domain_info nwl_msi_domain_info = {
> +	.flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
> +		  MSI_FLAG_MULTI_PCI_MSI),
> +	.chip = &nwl_msi_irq_chip,
> +};
> +#endif
> +
> +static void nwl_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
> +{
> +	struct nwl_pcie *pcie = irq_data_get_irq_chip_data(data);
> +	phys_addr_t msi_addr = pcie->phys_pcie_reg_base;
> +
> +	msg->address_lo = lower_32_bits(msi_addr);
> +	msg->address_hi = upper_32_bits(msi_addr);
> +	msg->data = data->hwirq;
> +}
> +
> +static int nwl_msi_set_affinity(struct irq_data *irq_data,
> +				const struct cpumask *mask, bool force)
> +{
> +	return -EINVAL;
> +}
> +
> +static struct irq_chip nwl_irq_chip = {
> +	.name = "Xilinx MSI",
> +	.irq_compose_msi_msg = nwl_compose_msi_msg,
> +	.irq_set_affinity = nwl_msi_set_affinity,
> +};
> +
> +static int nwl_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
> +				unsigned int nr_irqs, void *args)
> +{
> +	struct nwl_pcie *pcie = domain->host_data;
> +	struct nwl_msi *msi = &pcie->msi;
> +	int bit;
> +	int i;
> +
> +	mutex_lock(&msi->lock);
> +	bit = bitmap_find_next_zero_area(msi->bitmap, INT_PCI_MSI_NR, 0,
> +					 nr_irqs, 0);
> +
> +	if (bit < INT_PCI_MSI_NR)
> +		bitmap_set(msi->bitmap, bit, nr_irqs);
> +	else
> +		bit = -ENOSPC;
> +
> +	if (bit < 0) {
> +		mutex_unlock(&msi->lock);
> +		return bit;
> +	}

  mutex_lock(&msi->lock);
  bit = bitmap_find_next_zero_area(...);
  if (bit >= INT_PCI_MSI_NR) {
    mutex_unlock(&msi->lock);
    return -ENOSPC;
  }

  bitmap_set(msi->bitmap, bit, nr_irqs);
  ...

> +	for (i = 0; i < nr_irqs; i++) {
> +		irq_domain_set_info(domain, virq + i, bit + i, &nwl_irq_chip,
> +				domain->host_data, handle_simple_irq,
> +				NULL, NULL);
> +	}
> +	mutex_unlock(&msi->lock);
> +
> +	return 0;
> +}
> +
> +static void nwl_irq_domain_free(struct irq_domain *domain, unsigned int virq,
> +					unsigned int nr_irqs)
> +{
> +	struct irq_data *data = irq_domain_get_irq_data(domain, virq);
> +	struct nwl_pcie *pcie = irq_data_get_irq_chip_data(data);
> +	struct nwl_msi *msi = &pcie->msi;
> +
> +	mutex_lock(&msi->lock);
> +

Unnecessary blank lines.

> +	bitmap_clear(msi->bitmap, data->hwirq, nr_irqs);
> +
> +	mutex_unlock(&msi->lock);
> +}
> +
> +static const struct irq_domain_ops dev_msi_domain_ops = {
> +	.alloc  = nwl_irq_domain_alloc,
> +	.free   = nwl_irq_domain_free,
> +};
> +
> +static void nwl_msi_free_irq_domain(struct nwl_pcie *pcie)
> +{
> +	struct nwl_msi *msi = &pcie->msi;
> +
> +	if (msi->irq_msi0)
> +		irq_set_chained_handler_and_data(msi->irq_msi0, NULL, NULL);
> +	if (msi->irq_msi1)
> +		irq_set_chained_handler_and_data(msi->irq_msi1, NULL, NULL);
> +
> +	if (msi->msi_domain)
> +		irq_domain_remove(msi->msi_domain);
> +	if (msi->dev_domain)
> +		irq_domain_remove(msi->dev_domain);
> +
> +	kfree(msi->bitmap);
> +	msi->bitmap = NULL;
> +}
> +
> +static void nwl_pcie_free_irq_domain(struct nwl_pcie *pcie)
> +{
> +	int i;
> +	u32 irq;
> +
> +

Extra newline.

> +	for (i = 0; i < 4; i++) {
> +		irq = irq_find_mapping(pcie->legacy_irq_domain, i + 1);
> +		if (irq > 0)
> +			irq_dispose_mapping(irq);
> +	}
> +	if (pcie->legacy_irq_domain)
> +		irq_domain_remove(pcie->legacy_irq_domain);

Something seems wrong here.  I don't know when irq_dispose_mapping()
is required, but it's not used consistently in drivers/pci, and it
should be.  Currently, only pci-tegra.c, pcie-xilinx.c, and this new
driver use it.  Tegra uses it only for MSIs, and Xilinx seems to use
it for both MSIs and INTx.  What's right?

> +
> +	nwl_msi_free_irq_domain(pcie);
> +}
> +
> +static int nwl_pcie_init_msi_irq_domain(struct nwl_pcie *pcie)
> +{
> +#ifdef CONFIG_PCI_MSI
> +	struct device_node *node = pcie->dev->of_node;
> +	struct nwl_msi *msi = &pcie->msi;
> +
> +	msi->dev_domain = irq_domain_add_linear(NULL, INT_PCI_MSI_NR,
> +					&dev_msi_domain_ops, pcie);
> +	if (!msi->dev_domain) {
> +		dev_err(pcie->dev, "failed to create dev IRQ domain\n");
> +		return -ENOMEM;
> +	}
> +	msi->msi_domain = pci_msi_create_irq_domain(node,
> +							&nwl_msi_domain_info,
> +							msi->dev_domain);
> +	if (!msi->msi_domain) {
> +		dev_err(pcie->dev, "failed to create msi IRQ domain\n");
> +		irq_domain_remove(msi->dev_domain);
> +		return -ENOMEM;
> +	}
> +#endif
> +	return 0;
> +}
> +
> +static int nwl_pcie_init_irq_domain(struct nwl_pcie *pcie)
> +{
> +	struct device_node *node = pcie->dev->of_node;
> +	struct device_node *legacy_intc_node;
> +
> +	legacy_intc_node = of_get_next_child(node, NULL);
> +	if (!legacy_intc_node) {
> +		dev_err(pcie->dev, "No legacy intc node found\n");
> +		return PTR_ERR(legacy_intc_node);
> +	}
> +
> +	pcie->legacy_irq_domain = irq_domain_add_linear(legacy_intc_node, 4,

This "4", the one in nwl_pcie_free_irq_domain(), and the one in
nwl_pcie_leg_handler() should all be replaced by a #define so we know
they all refer to the same thing.

I see that xilinx_pcie_init_irq_domain() and
dra7xx_pcie_init_irq_domain() have a similar issue, and it'd
be nice to fix them, too (in a separate patch, of course).

> +							&legacy_domain_ops,
> +							pcie);
> +
> +	if (!pcie->legacy_irq_domain) {
> +		dev_err(pcie->dev, "failed to create IRQ domain\n");
> +		return -ENOMEM;
> +	}
> +
> +	nwl_pcie_init_msi_irq_domain(pcie);
> +
> +	return 0;
> +}
> +
> +static int nwl_pcie_enable_msi(struct nwl_pcie *pcie, struct pci_bus *bus)
> +{
> +	struct platform_device *pdev = to_platform_device(pcie->dev);
> +	struct nwl_msi *msi = &pcie->msi;
> +	unsigned long base;
> +	int ret;
> +	int size = BITS_TO_LONGS(INT_PCI_MSI_NR) * sizeof(long);
> +
> +	mutex_init(&msi->lock);
> +
> +	msi->bitmap = kzalloc(size, GFP_KERNEL);
> +	if (!msi->bitmap)
> +		return -ENOMEM;
> +
> +	/* Check for msii_present bit */
> +	ret = nwl_bridge_readl(pcie, I_MSII_CAPABILITIES) & MSII_PRESENT;
> +	if (!ret) {
> +		dev_err(pcie->dev, "MSI not present\n");
> +		ret = -EIO;
> +		goto err;

These error paths leak msi->bitmap.

> +	}
> +
> +	/* Enable MSII */
> +	nwl_bridge_writel(pcie, nwl_bridge_readl(pcie, I_MSII_CONTROL) |
> +			  MSII_ENABLE, I_MSII_CONTROL);
> +
> +	/* Enable MSII status */
> +	nwl_bridge_writel(pcie, nwl_bridge_readl(pcie, I_MSII_CONTROL) |
> +			  MSII_STATUS_ENABLE, I_MSII_CONTROL);
> +
> +	/* setup AFI/FPCI range */
> +	base = pcie->phys_pcie_reg_base;
> +	nwl_bridge_writel(pcie, lower_32_bits(base), I_MSII_BASE_LO);
> +	nwl_bridge_writel(pcie, upper_32_bits(base), I_MSII_BASE_HI);
> +
> +	/* Disable high range msi interrupts */

The comments before each line make the code harder to read.  Something like
this might be useful:

  /*
   * For high range MSI interrupts: disable, clear any pending, register
   * the handler, and enable.
   */

I think you could move the platform_get_irq_byname() calls up so they're
not in the middle of the hardware twiddling code.  That would also help the
code read better.

> +	nwl_bridge_writel(pcie, (u32)~MSGF_MSI_SR_HI_MASK, MSGF_MSI_MASK_HI);
> +
> +	/* Clear pending high range msi interrupts */
> +	nwl_bridge_writel(pcie, nwl_bridge_readl(pcie,  MSGF_MSI_STATUS_HI) &
> +			  MSGF_MSI_SR_HI_MASK, MSGF_MSI_STATUS_HI);
> +	/* Get msi_1 IRQ number */
> +	msi->irq_msi1 = platform_get_irq_byname(pdev, "msi1");
> +	if (msi->irq_msi1 < 0) {
> +		dev_err(&pdev->dev, "failed to get IRQ#%d\n", msi->irq_msi1);
> +		goto err;

"ret" contains "I_MSII_CAPABILITIES & MSII_PRESENT", so I think this and
the subsequent error paths return junk.

> +	}
> +	/* Register msi handler */
> +	irq_set_chained_handler_and_data(msi->irq_msi1,
> +					 nwl_pcie_msi_handler_high, pcie);
> +
> +	/* Enable all high range msi interrupts */
> +	nwl_bridge_writel(pcie, MSGF_MSI_SR_HI_MASK, MSGF_MSI_MASK_HI);
> +
> +	/* Disable low range msi interrupts */
> +	nwl_bridge_writel(pcie, (u32)~MSGF_MSI_SR_LO_MASK, MSGF_MSI_MASK_LO);
> +
> +	/* Clear pending low range msi interrupts */
> +	nwl_bridge_writel(pcie, nwl_bridge_readl(pcie, MSGF_MSI_STATUS_LO) &
> +			  MSGF_MSI_SR_LO_MASK, MSGF_MSI_STATUS_LO);
> +	/* Get msi_0 IRQ number */
> +	msi->irq_msi0 = platform_get_irq_byname(pdev, "msi0");
> +	if (msi->irq_msi0 < 0) {
> +		dev_err(&pdev->dev, "failed to get IRQ#%d\n", msi->irq_msi0);
> +		goto err;
> +	}
> +
> +	/* Register msi handler */
> +	irq_set_chained_handler_and_data(msi->irq_msi0,
> +					 nwl_pcie_msi_handler_low, pcie);
> +
> +	/* Enable all low range msi interrupts */
> +	nwl_bridge_writel(pcie, MSGF_MSI_SR_LO_MASK, MSGF_MSI_MASK_LO);
> +
> +	return 0;
> +err:
> +	return ret;
> +}
> +
> +static int nwl_pcie_bridge_init(struct nwl_pcie *pcie)
> +{
> +	struct platform_device *pdev = to_platform_device(pcie->dev);
> +	u32 breg_val, ecam_val, first_busno = 0;
> +	int err;
> +	int check_link_up = 0;
> +
> +	/* Check for BREG present bit */
> +	breg_val = nwl_bridge_readl(pcie, E_BREG_CAPABILITIES) & BREG_PRESENT;
> +	if (!breg_val) {
> +		dev_err(pcie->dev, "BREG is not present\n");
> +		return breg_val;
> +	}
> +	/* Write bridge_off to breg base */
> +	nwl_bridge_writel(pcie, lower_32_bits(pcie->phys_breg_base),
> +			  E_BREG_BASE_LO);
> +	nwl_bridge_writel(pcie, upper_32_bits(pcie->phys_breg_base),
> +			  E_BREG_BASE_HI);
> +
> +	/* Enable BREG */
> +	nwl_bridge_writel(pcie, ~BREG_ENABLE_FORCE & BREG_ENABLE,
> +			  E_BREG_CONTROL);
> +
> +	/* Disable DMA channel registers */
> +	nwl_bridge_writel(pcie, nwl_bridge_readl(pcie, BRCFG_PCIE_RX0) |
> +			  CFG_DMA_REG_BAR, BRCFG_PCIE_RX0);
> +
> +	/* Enable the bridge config interrupt */
> +	nwl_bridge_writel(pcie, nwl_bridge_readl(pcie, BRCFG_INTERRUPT) |
> +			  BRCFG_INTERRUPT_MASK, BRCFG_INTERRUPT);
> +	/* Enable Ingress subtractive decode translation */
> +	nwl_bridge_writel(pcie, SET_ISUB_CONTROL, I_ISUB_CONTROL);
> +
> +	/* Enable msg filtering details */
> +	nwl_bridge_writel(pcie, CFG_ENABLE_MSG_FILTER_MASK,
> +			  BRCFG_PCIE_RX_MSG_FILTER);
> +	do {
> +		err = nwl_pcie_link_up(pcie, PHY_RDY_LINKUP);
> +		if (err != 1) {

nwl_pcie_link_up() is defined to return "bool", so you should use it that
way, e.g., save the result in something like "link_up" and test as
"if (!link_up)" instead of testing a bool against "1".

> +			check_link_up++;
> +			if (check_link_up > LINKUP_ITER_CHECK)
> +				return -ENODEV;
> +			msleep(1000);
> +		}
> +	} while (!err);
> +
> +	/* Check for ECAM present bit */

Superfluous comment.

> +	ecam_val = nwl_bridge_readl(pcie, E_ECAM_CAPABILITIES) & E_ECAM_PRESENT;
> +	if (!ecam_val) {
> +		dev_err(pcie->dev, "ECAM is not present\n");
> +		return ecam_val;
> +	}
> +
> +	/* Enable ECAM */

This comment is useful, but the ones below are distracting because you can
read the same thing from the code.

> +	nwl_bridge_writel(pcie, nwl_bridge_readl(pcie, E_ECAM_CONTROL) |
> +			  E_ECAM_CR_ENABLE, E_ECAM_CONTROL);
> +	/* Write ecam_value on ecam_control */
> +	nwl_bridge_writel(pcie, nwl_bridge_readl(pcie, E_ECAM_CONTROL) |
> +			  (pcie->ecam_value << E_ECAM_SIZE_SHIFT),
> +			  E_ECAM_CONTROL);
> +	/* Write phy_reg_base to ecam base */
> +	nwl_bridge_writel(pcie, lower_32_bits(pcie->phys_ecam_base),
> +			  E_ECAM_BASE_LO);
> +	nwl_bridge_writel(pcie, upper_32_bits(pcie->phys_ecam_base),
> +			  E_ECAM_BASE_HI);
> +
> +	/* Get bus range */
> +	ecam_val = nwl_bridge_readl(pcie, E_ECAM_CONTROL);
> +	pcie->last_busno = (ecam_val & E_ECAM_SIZE_LOC) >> E_ECAM_SIZE_SHIFT;
> +	/* Write primary, secondary and subordinate bus numbers */
> +	ecam_val = first_busno;
> +	ecam_val |= (first_busno + 1) << 8;
> +	ecam_val |= (pcie->last_busno << E_ECAM_SIZE_SHIFT);
> +	writel(ecam_val, (pcie->ecam_base + PCI_PRIMARY_BUS));
> +
> +	/* Check if PCIe link is up? */

Remove the comment; it's obvious from the code.

> +	pcie->link_up = nwl_pcie_link_up(pcie, PCIE_USER_LINKUP);
> +	if (!pcie->link_up)
> +		dev_info(pcie->dev, "Link is DOWN\n");
> +	else
> +		dev_info(pcie->dev, "Link is UP\n");

Avoid the negation with:

  if (pcie->link_up)
    dev_info(pcie->dev, "Link is UP\n");
  else
    dev_info(pcie->dev, "Link is DOWN\n");

or

  dev_info(pcie->dev, "Link is %s\n", pcie->link_up ? "UP" : "DOWN");

> +
> +	/* Disable all misc interrupts */
> +	nwl_bridge_writel(pcie, (u32)~MSGF_MISC_SR_MASKALL, MSGF_MISC_MASK);
> +
> +	/* Clear pending misc interrupts */
> +	nwl_bridge_writel(pcie, nwl_bridge_readl(pcie, MSGF_MISC_STATUS) &
> +			  MSGF_MISC_SR_MASKALL, MSGF_MISC_STATUS);
> +
> +	/* Get misc IRQ number */
> +	pcie->irq_misc = platform_get_irq_byname(pdev, "misc");
> +	if (pcie->irq_misc < 0) {
> +		dev_err(&pdev->dev, "failed to get misc IRQ %d\n",
> +			pcie->irq_misc);
> +		return -EINVAL;
> +	}
> +	/* Register misc handler */
> +	err = devm_request_irq(pcie->dev, pcie->irq_misc,
> +			       nwl_pcie_misc_handler, IRQF_SHARED,
> +			       "nwl_pcie:misc", pcie);
> +	if (err) {
> +		dev_err(pcie->dev, "fail to register misc IRQ#%d\n",
> +			pcie->irq_misc);
> +		return err;
> +	}
> +	/* Enable all misc interrupts */
> +	nwl_bridge_writel(pcie, MSGF_MISC_SR_MASKALL, MSGF_MISC_MASK);
> +
> +	/* Disable all legacy interrupts */
> +	nwl_bridge_writel(pcie, (u32)~MSGF_LEG_SR_MASKALL, MSGF_LEG_MASK);
> +
> +	/* Clear pending legacy interrupts */
> +	nwl_bridge_writel(pcie, nwl_bridge_readl(pcie, MSGF_LEG_STATUS) &
> +			  MSGF_LEG_SR_MASKALL, MSGF_LEG_STATUS);
> +
> +	/* Enable all legacy interrupts */
> +	nwl_bridge_writel(pcie, MSGF_LEG_SR_MASKALL, MSGF_LEG_MASK);
> +
> +	return 0;
> +}
> +
> +static int nwl_pcie_parse_dt(struct nwl_pcie *pcie,
> +					struct platform_device *pdev)
> +{
> +	struct device_node *node = pcie->dev->of_node;
> +	struct resource *res;
> +	const char *type;
> +
> +	/* Check for device type */
> +	type = of_get_property(node, "device_type", NULL);
> +	if (!type || strcmp(type, "pci")) {
> +		dev_err(pcie->dev, "invalid \"device_type\" %s\n", type);
> +		return -EINVAL;
> +	}
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "breg");
> +	pcie->breg_base = devm_ioremap_resource(pcie->dev, res);
> +	if (IS_ERR(pcie->breg_base))
> +		return PTR_ERR(pcie->breg_base);
> +	pcie->phys_breg_base = res->start;
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pcireg");
> +	pcie->pcireg_base = devm_ioremap_resource(pcie->dev, res);
> +	if (IS_ERR(pcie->pcireg_base))
> +		return PTR_ERR(pcie->pcireg_base);
> +	pcie->phys_pcie_reg_base = res->start;
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cfg");
> +	pcie->ecam_base = devm_ioremap_resource(pcie->dev, res);
> +	if (IS_ERR(pcie->ecam_base))
> +		return PTR_ERR(pcie->ecam_base);
> +	pcie->phys_ecam_base = res->start;
> +
> +	/* Get intx IRQ number */
> +	pcie->irq_intx = platform_get_irq_byname(pdev, "intx");
> +	if (pcie->irq_intx < 0) {
> +		dev_err(&pdev->dev, "failed to get intx IRQ %d\n",
> +			pcie->irq_intx);
> +		return -EINVAL;
> +	}
> +
> +	/* Register intx handler */
> +	irq_set_chained_handler_and_data(pcie->irq_intx,
> +					 nwl_pcie_leg_handler, pcie);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id nwl_pcie_of_match[] = {
> +	{ .compatible = "xlnx,nwl-pcie-2.11", },
> +	{}
> +};
> +
> +static int nwl_pcie_probe(struct platform_device *pdev)
> +{
> +	struct device_node *node = pdev->dev.of_node;
> +	struct nwl_pcie *pcie;
> +	struct pci_bus *bus;
> +	int err;
> +

Remove extra blank line.

> +	resource_size_t iobase = 0;
> +	LIST_HEAD(res);
> +
> +	pcie = devm_kzalloc(&pdev->dev, sizeof(*pcie), GFP_KERNEL);
> +	if (!pcie)
> +		return -ENOMEM;
> +
> +	pcie->ecam_value = NWL_ECAM_VALUE_DEFAULT;
> +
> +	pcie->dev = &pdev->dev;
> +
> +	err = nwl_pcie_parse_dt(pcie, pdev);
> +	if (err) {
> +		dev_err(pcie->dev, "Parsing DT failed\n");
> +		return err;

This leaks the nwl_pcie struct you just allocated.  And all the subsequent
error paths do too, of course.

> +	}
> +	/* Bridge initialization */
> +	err = nwl_pcie_bridge_init(pcie);
> +	if (err) {
> +		dev_err(pcie->dev, "HW Initalization failed\n");
> +		return err;
> +	}
> +
> +	err = of_pci_get_host_bridge_resources(node, 0, 0xff, &res, &iobase);
> +	if (err) {
> +		pr_err("Getting bridge resources failed\n");
> +		return err;
> +	}
> +
> +	err = nwl_pcie_init_irq_domain(pcie);
> +	if (err) {
> +		dev_err(pcie->dev, "Failed creating IRQ Domain\n");
> +		return err;
> +	}
> +
> +	bus = pci_create_root_bus(&pdev->dev, pcie->root_busno,
> +				  &nwl_pcie_ops, pcie, &res);
> +	if (!bus)
> +		return -ENOMEM;
> +
> +	/* Enable MSI */

Comment is superfluous.

> +	if (IS_ENABLED(CONFIG_PCI_MSI)) {
> +		err = nwl_pcie_enable_msi(pcie, bus);
> +		if (err < 0) {
> +			dev_err(&pdev->dev,
> +				"failed to enable MSI support: %d\n", err);
> +			return err;
> +		}
> +	}
> +	pci_scan_child_bus(bus);
> +	pci_assign_unassigned_bus_resources(bus);
> +	pcie_bus_configure_settings(bus);
> +	pci_bus_add_devices(bus);
> +	platform_set_drvdata(pdev, pcie);
> +
> +	return 0;
> +}
> +
> +static int nwl_pcie_remove(struct platform_device *pdev)
> +{
> +	struct nwl_pcie *pcie = platform_get_drvdata(pdev);
> +
> +	nwl_pcie_free_irq_domain(pcie);
> +	platform_set_drvdata(pdev, NULL);

This leaks the nwl_pcie struct.

> +	return 0;
> +}
> +
> +static struct platform_driver nwl_pcie_driver = {
> +	.driver = {
> +		.name = "nwl-pcie",
> +		.of_match_table = nwl_pcie_of_match,
> +	},
> +	.probe = nwl_pcie_probe,
> +	.remove = nwl_pcie_remove,
> +};
> +module_platform_driver(nwl_pcie_driver);
> +
> +MODULE_AUTHOR("Xilinx, Inc");
> +MODULE_DESCRIPTION("NWL PCIe driver");
> +MODULE_LICENSE("GPL");
> -- 
> 2.1.1
> 
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