Re: [PATCH v2 2/2] PCI: meson: add the Amlogic Meson PCIe controller driver

[Jerome Brunet]

On Fri, 2018-08-24 at 15:36 +0800, Hanjie Lin wrote:
> From: Yue Wang <yue.wang@xxxxxxxxxxx>
> 
> The Amlogic Meson PCIe host controller is based on the Synopsys DesignWare
> PCI core. This patch adds the driver support for Meson PCIe controller.
> 
> Signed-off-by: Yue Wang <yue.wang@xxxxxxxxxxx>
> Signed-off-by: Hanjie Lin <hanjie.lin@xxxxxxxxxxx>
> ---
>  drivers/pci/controller/dwc/Kconfig     |  12 +
>  drivers/pci/controller/dwc/Makefile    |   1 +
>  drivers/pci/controller/dwc/pci-meson.c | 613 +++++++++++++++++++++++++++++++++
>  3 files changed, 626 insertions(+)
>  create mode 100644 drivers/pci/controller/dwc/pci-meson.c
> 
> diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
> index 91b0194..6cb36f6 100644
> --- a/drivers/pci/controller/dwc/Kconfig
> +++ b/drivers/pci/controller/dwc/Kconfig
> @@ -193,4 +193,16 @@ config PCIE_HISI_STB
>  	help
>            Say Y here if you want PCIe controller support on HiSilicon STB SoCs
>  
> +config PCI_MESON
> +	bool "MESON PCIe controller"
> +	depends on PCI
> +	depends on PCI_MSI_IRQ_DOMAIN
> +	select PCIEPORTBUS
> +	select PCIE_DW_HOST
> +	help
> +	  Say Y here if you want to enable PCI controller support on Amlogic
> +	  SoCs. The PCI controller on Amlogic is based on DesignWare hardware
> +	  and therefore the driver re-uses the DesignWare core functions to
> +	  implement the driver.
> +
>  endmenu
> diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
> index 5d2ce72..cf676bd 100644
> --- a/drivers/pci/controller/dwc/Makefile
> +++ b/drivers/pci/controller/dwc/Makefile
> @@ -14,6 +14,7 @@ obj-$(CONFIG_PCIE_ARMADA_8K) += pcie-armada8k.o
>  obj-$(CONFIG_PCIE_ARTPEC6) += pcie-artpec6.o
>  obj-$(CONFIG_PCIE_KIRIN) += pcie-kirin.o
>  obj-$(CONFIG_PCIE_HISI_STB) += pcie-histb.o
> +obj-$(CONFIG_PCI_MESON) += pci-meson.o
>  
>  # The following drivers are for devices that use the generic ACPI
>  # pci_root.c driver but don't support standard ECAM config access.
> diff --git a/drivers/pci/controller/dwc/pci-meson.c b/drivers/pci/controller/dwc/pci-meson.c
> new file mode 100644
> index 0000000..a9edf20
> --- /dev/null
> +++ b/drivers/pci/controller/dwc/pci-meson.c
> @@ -0,0 +1,613 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * PCIe host controller driver for Amlogic MESON SoCs
> + *
> + * Copyright (c) 2018 Amlogic, inc.
> + * Author: Yue Wang <yue.wang@xxxxxxxxxxx>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/of_device.h>
> +#include <linux/of_gpio.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +#include <linux/phy/phy.h>
> +#include <linux/resource.h>
> +#include <linux/types.h>
> +#include <linux/reset.h>
> +
> +#include "pcie-designware.h"
> +
> +#define to_meson_pcie(x) dev_get_drvdata((x)->dev)
> +
> +/* External local bus interface registers */
> +#define PLR_OFFSET			0x700
> +#define PCIE_PORT_LINK_CTRL_OFF		(PLR_OFFSET + 0x10)
> +#define FAST_LINK_MODE			BIT(7)
> +#define LINK_CAPABLE_MASK		GENMASK(21, 16)
> +#define LINK_CAPABLE_X1			BIT(16)
> +
> +#define PCIE_GEN2_CTRL_OFF		(PLR_OFFSET + 0x10c)
> +#define NUM_OF_LANES_MASK		GENMASK(12, 8)
> +#define NUM_OF_LANES_X1			BIT(8)
> +#define DIRECT_SPEED_CHANGE		BIT(17)
> +
> +#define TYPE1_HDR_OFFSET		0x0
> +#define PCIE_STATUS_COMMAND		(TYPE1_HDR_OFFSET + 0x04)
> +#define PCI_IO_EN			BIT(0)
> +#define PCI_MEM_SPACE_EN		BIT(1)
> +#define PCI_BUS_MASTER_EN		BIT(2)
> +
> +#define PCIE_BASE_ADDR0			(TYPE1_HDR_OFFSET + 0x10)
> +#define PCIE_BASE_ADDR1			(TYPE1_HDR_OFFSET + 0x14)
> +
> +#define PCIE_CAP_OFFSET			0x70
> +#define PCIE_DEV_CTRL_DEV_STUS		(PCIE_CAP_OFFSET + 0x08)
> +#define PCIE_CAP_MAX_PAYLOAD_MASK	GENMASK(7, 5)
> +#define PCIE_CAP_MAX_PAYLOAD_SIZE(x)	((x) << 5)
> +#define PCIE_CAP_MAX_READ_REQ_MASK	GENMASK(14, 12)
> +#define PCIE_CAP_MAX_READ_REQ_SIZE(x)	((x) << 12)
> +
> +#define PCI_CLASS_REVISION_MASK		GENMASK(7, 0)
> +
> +/* PCIe specific config registers */
> +#define PCIE_CFG0			0x0
> +#define APP_LTSSM_ENABLE		BIT(7)
> +
> +#define PCIE_CFG_STATUS12		0x30
> +#define IS_SMLH_LINK_UP(x)		((x) & (1 << 6))
> +#define IS_RDLH_LINK_UP(x)		((x) & (1 << 16))
> +#define IS_LTSSM_UP(x)			((((x) >> 10) & 0x1f) == 0x11)
> +
> +#define PCIE_CFG_STATUS17		0x44
> +#define PM_CURRENT_STATE(x)		(((x) >> 7) & 0x1)
> +
> +#define WAIT_LINKUP_TIMEOUT		2000
> +#define PORT_CLK_RATE			100000000UL
> +#define MAX_PAYLOAD_SIZE		256
> +#define MAX_READ_REQ_SIZE		256
> +
> +enum pcie_data_rate {
> +	PCIE_GEN1,
> +	PCIE_GEN2,
> +	PCIE_GEN3,
> +	PCIE_GEN4
> +};
> +
> +struct meson_pcie_mem_res {
> +	void __iomem *elbi_base; /* DT 0th resource */
> +	void __iomem *cfg_base; /* DT 2nd resource */
> +};
> +
> +struct meson_pcie_clk_res {
> +	struct clk *clk;
> +	struct clk *mipi_gate;
> +	struct clk *port_clk;
> +	struct clk *general_clk;
> +};
> +
> +struct meson_pcie_rc_reset {
> +	struct reset_control *port;
> +	struct reset_control *apb;
> +};
> +
> +struct meson_pcie {
> +	struct dw_pcie pci;
> +	struct meson_pcie_mem_res mem_res;
> +	struct meson_pcie_clk_res clk_res;
> +	struct meson_pcie_rc_reset mrst;
> +	struct gpio_desc *reset_gpio;
> +
> +	struct phy *phy;
> +	enum of_gpio_flags gpio_flag;
> +	int pcie_num;
> +	u32 port_num;
> +	u32 device_attch;
> +};
> +
> +static int meson_pcie_get_mem(struct platform_device *pdev,
> +			      struct meson_pcie *mp)
> +{
> +	struct device *dev = mp->pci.dev;
> +	struct resource *res;
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "elbi");
> +	if (!res)
> +		return -ENODEV;
> +
> +	mp->mem_res.elbi_base = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(mp->mem_res.elbi_base))
> +		return PTR_ERR(mp->mem_res.elbi_base);
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cfg");
> +	if (!res)
> +		return -ENODEV;
> +
> +	mp->mem_res.cfg_base = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(mp->mem_res.cfg_base))
> +		return PTR_ERR(mp->mem_res.cfg_base);
> +
> +	return 0;
> +}
> +
> +static void meson_pcie_rc_reset(struct meson_pcie *mp)
> +{
> +	struct meson_pcie_rc_reset *mrst = &mp->mrst;
> +
> +	reset_control_assert(mrst->port);
> +	reset_control_assert(mrst->apb);
> +	udelay(400);
> +	reset_control_deassert(mrst->port);
> +	reset_control_deassert(mrst->apb);
> +	udelay(500);
> +}
> +
> +static int meson_pcie_init_clk(struct meson_pcie *mp)
> +{
> +	struct device *dev = mp->pci.dev;
> +	struct meson_pcie_clk_res *res = &mp->clk_res;
> +	int ret;
> +
> +	res->port_clk = devm_clk_get(dev, "port");
> +	if (IS_ERR(res->port_clk)) {
> +		if (PTR_ERR(res->port_clk) != -EPROBE_DEFER)
> +			dev_err(dev, "Failed to get pcie port clock\n");
> +
> +		return PTR_ERR(res->port_clk);
> +	}
> +
> +	res->mipi_gate = devm_clk_get(dev, "pcie_mipi_en");
> +	if (IS_ERR(res->mipi_gate)) {
> +		if (PTR_ERR(res->mipi_gate) != -EPROBE_DEFER)
> +			dev_err(dev, "Failed to get pcie mipi clock\n");
> +
> +		return PTR_ERR(res->mipi_gate);
> +	}
> +
> +	res->general_clk = devm_clk_get(dev, "pcie_general");
> +	if (IS_ERR(res->general_clk)) {
> +		if (PTR_ERR(res->general_clk) != -EPROBE_DEFER)
> +			dev_err(dev, "Failed to get pcie general clock\n");
> +
> +		return PTR_ERR(res->general_clk);
> +	}
> +
> +	res->clk = devm_clk_get(dev, "pcie");
> +	if (IS_ERR(res->clk)) {
> +		if (PTR_ERR(res->clk) != -EPROBE_DEFER)
> +			dev_err(dev, "Failed to get pcie rc clock\n");
> +
> +		return PTR_ERR(res->clk);
> +	}
> +
> +	phy_init(mp->phy);
> +	meson_pcie_rc_reset(mp);
> +
> +	ret = clk_set_rate(res->port_clk, PORT_CLK_RATE);
> +	if (ret) {
> +		dev_err(dev, "set bus clk rate failed, ret = %d", ret);
> +		goto err_clk;
> +	}
> +
> +	ret = clk_prepare_enable(res->port_clk);
> +	if (ret) {
> +		dev_err(dev, "cannot enable pcie port clock");
> +		goto err_clk;
> +	}
> +
> +	ret = clk_prepare_enable(res->mipi_gate);
> +	if (ret) {
> +		dev_err(dev, "cannot enable pcie mipi gate clock");
> +		goto err_port_clk;
> +	}
> +
> +	ret = clk_prepare_enable(res->general_clk);
> +	if (ret) {
> +		dev_err(dev, "cannot enable pcie general clock");
> +		goto err_mipi_gate;
> +	}
> +
> +	ret = clk_prepare_enable(res->clk);
> +	if (ret) {
> +		dev_err(dev, "cannot enable pcie rc clock");
> +		goto err_general_clk;
> +	}
> +
> +	return 0;
> +
> +err_general_clk:
> +	clk_disable_unprepare(res->general_clk);
> +err_mipi_gate:
> +	clk_disable_unprepare(res->mipi_gate);
> +err_port_clk:
> +	clk_disable_unprepare(res->port_clk);
> +err_clk:
> +	return ret;

You are doing this from device probe but there is no remove counter part,
meaning the clock will be left enabled when the device is removed (and clock
count unbalanced). To just fire and forget clock, like you are doing, you could
use :

devm_add_action_or_reset(dev, (void(*)(void *))clk_disable_unprepare,
				<you-clk>);

This will take care of the errors cases and driver removal
Maybe you could make an helper function to do the get - enable - add reset.
Also, if the you just fire and forget the clock in this way, you don't need to
keep the clock pointer around (in your device data)

Last, do you really need to enable all the clocks at probe time ? Can't some be
enabled later on. I don't know much about pcie but maybe some enable could be
delayed until the pcie bus is actually connected to something ? in use ?

> +}
> +
> +static void meson_pcie_deinit_clk(struct meson_pcie *mp)
> +{
> +	clk_disable_unprepare(mp->clk_res.clk);
> +	clk_disable_unprepare(mp->clk_res.general_clk);
> +	clk_disable_unprepare(mp->clk_res.mipi_gate);
> +	clk_disable_unprepare(mp->clk_res.port_clk);
> +}

... then you can remove this function

> +
> +static inline void meson_elb_writel(struct meson_pcie *mp, u32 val, u32 reg)
> +{
> +	writel(val, mp->mem_res.elbi_base + reg);
> +}
> +
> +static inline u32 meson_elb_readl(struct meson_pcie *mp, u32 reg)
> +{
> +	return readl(mp->mem_res.elbi_base + reg);
> +}
> +
> +static inline u32 meson_cfg_readl(struct meson_pcie *mp, u32 reg)
> +{
> +	return readl(mp->mem_res.cfg_base + reg);
> +}
> +
> +static inline void meson_cfg_writel(struct meson_pcie *mp, u32 val, u32 reg)
> +{
> +	writel(val, mp->mem_res.cfg_base + reg);
> +}
> +
> +static void meson_pcie_assert_reset(struct meson_pcie *mp)
> +{
> +	gpiod_set_value_cansleep(mp->reset_gpio, 0);
> +	udelay(500);
> +	gpiod_set_value_cansleep(mp->reset_gpio, 1);
> +}
> +
> +static void meson_pcie_init_dw(struct meson_pcie *mp)
> +{
> +	u32 val = 0;
> +
> +	val = meson_cfg_readl(mp, PCIE_CFG0);
> +	val |= APP_LTSSM_ENABLE;
> +	meson_cfg_writel(mp, val, PCIE_CFG0);
> +
> +	val = meson_elb_readl(mp, PCIE_PORT_LINK_CTRL_OFF);
> +	val &= ~LINK_CAPABLE_MASK;
> +	meson_elb_writel(mp, val, PCIE_PORT_LINK_CTRL_OFF);
> +
> +	val = meson_elb_readl(mp, PCIE_PORT_LINK_CTRL_OFF);
> +	val |= LINK_CAPABLE_X1 | FAST_LINK_MODE;
> +	meson_elb_writel(mp, val, PCIE_PORT_LINK_CTRL_OFF);
> +
> +	val = meson_elb_readl(mp, PCIE_GEN2_CTRL_OFF);
> +	val &= ~NUM_OF_LANES_MASK;
> +	meson_elb_writel(mp, val, PCIE_GEN2_CTRL_OFF);
> +
> +	val = meson_elb_readl(mp, PCIE_GEN2_CTRL_OFF);
> +	val |= NUM_OF_LANES_X1 | DIRECT_SPEED_CHANGE;
> +	meson_elb_writel(mp, val, PCIE_GEN2_CTRL_OFF);
> +
> +	meson_elb_writel(mp, 0x0, PCIE_BASE_ADDR0);
> +	meson_elb_writel(mp, 0x0, PCIE_BASE_ADDR1);
> +}
> +
> +static int meson_size_to_payload(int size)
> +{
> +	if (size & (size - 1) || size < 128 || size > 4096)
> +		return 1;
> +
> +	return fls(size) - 8;
> +}
> +
> +static void meson_set_max_payload(struct meson_pcie *mp, int size)
> +{
> +	u32 val = 0;
> +	int max_payload_size = meson_size_to_payload(size);
> +
> +	val = meson_elb_readl(mp, PCIE_DEV_CTRL_DEV_STUS);
> +	val &= ~PCIE_CAP_MAX_PAYLOAD_MASK;
> +	meson_elb_writel(mp, val, PCIE_DEV_CTRL_DEV_STUS);
> +
> +	val = meson_elb_readl(mp, PCIE_DEV_CTRL_DEV_STUS);
> +	val |= PCIE_CAP_MAX_PAYLOAD_SIZE(max_payload_size);
> +	meson_elb_writel(mp, val, PCIE_DEV_CTRL_DEV_STUS);
> +}
> +
> +static void meson_set_max_rd_req_size(struct meson_pcie *mp, int size)
> +{
> +	u32 val = 0;
> +	int max_rd_req_size = meson_size_to_payload(size);
> +
> +	val = meson_elb_readl(mp, PCIE_DEV_CTRL_DEV_STUS);
> +	val &= ~PCIE_CAP_MAX_READ_REQ_MASK;
> +	meson_elb_writel(mp, val, PCIE_DEV_CTRL_DEV_STUS);
> +
> +	val = meson_elb_readl(mp, PCIE_DEV_CTRL_DEV_STUS);
> +	val |= PCIE_CAP_MAX_READ_REQ_SIZE(max_rd_req_size);
> +	meson_elb_writel(mp, val, PCIE_DEV_CTRL_DEV_STUS);
> +}
> +
> +static inline void meson_enable_memory_space(struct meson_pcie *mp)
> +{
> +	/* Set the RC Bus Master, Memory Space and I/O Space enables */
> +	meson_elb_writel(mp, PCI_IO_EN | PCI_MEM_SPACE_EN | PCI_BUS_MASTER_EN,
> +			 PCIE_STATUS_COMMAND);
> +}
> +
> +static int meson_pcie_establish_link(struct meson_pcie *mp)
> +{
> +	struct dw_pcie *pci = &mp->pci;
> +	struct pcie_port *pp = &pci->pp;
> +
> +	meson_pcie_init_dw(mp);
> +	meson_set_max_payload(mp, MAX_PAYLOAD_SIZE);
> +	meson_set_max_rd_req_size(mp, MAX_READ_REQ_SIZE);
> +
> +	dw_pcie_setup_rc(pp);
> +	meson_enable_memory_space(mp);
> +
> +	meson_pcie_assert_reset(mp);
> +
> +	/* check if the link is up or not */
> +	if (!dw_pcie_wait_for_link(pci))
> +		return 0;
> +
> +	return -ETIMEDOUT;
> +}
> +
> +static void meson_pcie_msi_init(struct meson_pcie *mp)
> +{
> +	struct pcie_port *pp = &mp->pci.pp;
> +
> +	dw_pcie_msi_init(pp);
> +}
> +
> +static void meson_pcie_enable_interrupts(struct meson_pcie *mp)
> +{
> +	if (IS_ENABLED(CONFIG_PCI_MSI))
> +		meson_pcie_msi_init(mp);
> +}
> +
> +static u32 meson_pcie_read_dbi(struct dw_pcie *pci, void __iomem *base,
> +			       u32 reg, size_t size)
> +{
> +	u32 val;
> +
> +	dw_pcie_read(base + reg, size, &val);
> +
> +	return val;
> +}
> +
> +static void meson_pcie_write_dbi(struct dw_pcie *pci, void __iomem *base,
> +				 u32 reg, size_t size, u32 val)
> +{
> +	dw_pcie_write(base + reg, size, val);
> +}
> +
> +static int meson_pcie_rd_own_conf(struct pcie_port *pp, int where, int size,
> +				  u32 *val)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct meson_pcie *mp = to_meson_pcie(pci);
> +
> +	if (!mp->device_attch)
> +		return 0;
> +
> +	/* the device class is not reported correctly from the register */
> +	if (where == PCI_CLASS_REVISION) {
> +		*val = readl(pci->dbi_base + PCI_CLASS_REVISION);
> +		/* keep revision id */
> +		*val &= PCI_CLASS_REVISION_MASK;
> +		*val |= PCI_CLASS_BRIDGE_PCI << 16;
> +		return PCIBIOS_SUCCESSFUL;
> +	}
> +
> +	return dw_pcie_read(pci->dbi_base + where, size, val);
> +}
> +
> +static int meson_pcie_wr_own_conf(struct pcie_port *pp, int where,
> +				  int size, u32 val)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct meson_pcie *mp = to_meson_pcie(pci);
> +
> +	if (!mp->device_attch)
> +		return 0;
> +
> +	return dw_pcie_write(pci->dbi_base + where, size, val);
> +}
> +
> +static int meson_pcie_link_up(struct dw_pcie *pci)
> +{
> +	struct meson_pcie *mp = to_meson_pcie(pci);
> +	struct device *dev = pci->dev;
> +	u32 smlh_up = 0;
> +	u32 ltssm_up = 0;
> +	u32 rdlh_up = 0;
> +	u32 speed_okay = 0;
> +	u32 cnt = 0;
> +	u32 state12, state17;
> +
> +	while (smlh_up == 0 || rdlh_up == 0 || ltssm_up == 0 ||
> +	       speed_okay == 0) {
> +		udelay(20);
> +
> +		state12 = meson_cfg_readl(mp, PCIE_CFG_STATUS12);
> +		state17 = meson_cfg_readl(mp, PCIE_CFG_STATUS17);
> +		smlh_up = IS_SMLH_LINK_UP(state12);
> +		rdlh_up = IS_RDLH_LINK_UP(state12);
> +		ltssm_up = IS_LTSSM_UP(state12);
> +
> +		if (PM_CURRENT_STATE(state17) < PCIE_GEN3)
> +			speed_okay = 1;
> +
> +		if (smlh_up)
> +			dev_dbg(dev, "smlh_link_up is on\n");
> +		if (rdlh_up)
> +			dev_dbg(dev, "rdlh_link_up is on\n");
> +		if (ltssm_up)
> +			dev_dbg(dev, "ltssm_up is on\n");
> +		if (speed_okay)
> +			dev_dbg(dev, "speed_okay\n");
> +
> +		cnt++;
> +
> +		if (cnt >= WAIT_LINKUP_TIMEOUT) {
> +			dev_err(dev, "Error: Wait linkup timeout.\n");
> +			return 0;
> +		}
> +	}
> +
> +	return 1;
> +}
> +
> +static int meson_pcie_host_init(struct pcie_port *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct meson_pcie *mp = to_meson_pcie(pci);
> +	int ret;
> +
> +	ret = meson_pcie_establish_link(mp);
> +
> +	if (ret)
> +		return ret;
> +
> +	mp->device_attch = 1;
> +	meson_pcie_enable_interrupts(mp);
> +
> +	return 0;
> +}
> +
> +static const struct dw_pcie_host_ops meson_pcie_host_ops = {
> +	.rd_own_conf = meson_pcie_rd_own_conf,
> +	.wr_own_conf = meson_pcie_wr_own_conf,
> +	.host_init = meson_pcie_host_init,
> +};
> +
> +static int meson_add_pcie_port(struct meson_pcie *mp,
> +			       struct platform_device *pdev)
> +{
> +	struct dw_pcie *pci = &mp->pci;
> +	struct pcie_port *pp = &pci->pp;
> +	struct device *dev = &pdev->dev;
> +	int ret;
> +
> +	if (IS_ENABLED(CONFIG_PCI_MSI)) {
> +		pp->msi_irq = platform_get_irq(pdev, 0);
> +		if (pp->msi_irq < 0) {
> +			dev_err(dev, "failed to get msi irq\n");
> +			return pp->msi_irq;
> +		}
> +	}
> +
> +	pp->root_bus_nr = -1;
> +	pp->ops = &meson_pcie_host_ops;
> +	pci->dbi_base = mp->mem_res.elbi_base;
> +
> +	ret = dw_pcie_host_init(pp);
> +	if (ret) {
> +		dev_err(dev, "failed to initialize host\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct dw_pcie_ops dw_pcie_ops = {
> +	.read_dbi = meson_pcie_read_dbi,
> +	.write_dbi = meson_pcie_write_dbi,
> +	.link_up = meson_pcie_link_up,
> +};
> +
> +static int meson_pcie_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node;
> +	struct dw_pcie *pci;
> +	struct meson_pcie *mp;
> +	struct meson_pcie_rc_reset *mrst;
> +	int ret;
> +
> +	mp = devm_kzalloc(dev, sizeof(*mp), GFP_KERNEL);
> +	if (!mp)
> +		return -ENOMEM;
> +
> +	pci = &mp->pci;
> +	pci->dev = dev;
> +	pci->ops = &dw_pcie_ops;
> +
> +	mp->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
> +	if (IS_ERR(mp->reset_gpio)) {
> +		dev_err(dev, "Get reset gpio failed\n");
> +		return PTR_ERR(mp->reset_gpio);
> +	}
> +
> +	mp->phy = devm_of_phy_get(dev, np, NULL);

For the 3rd time, you do *not* need a phy driver to just handle a reset line.
It is overkill.

you should claim the shared reset line here and be done with it.

> +	if (IS_ERR(mp->phy)) {
> +		if (PTR_ERR(mp->phy) != -EPROBE_DEFER)
> +			dev_err(dev, "Get phy failed, set default %ld\n",
> +				PTR_ERR(mp->phy));
> +		return PTR_ERR(mp->phy);
> +	}
> +
> +	mrst = &mp->mrst;
> +
> +	mrst->port = devm_reset_control_get_shared(dev, "port");

There is no reason for this reset to be shared since there is one per pcie port.

> +	if (IS_ERR(mrst->port)) {
> +		if (PTR_ERR(mrst->port) != -EPROBE_DEFER)
> +			dev_err(dev, "couldn't get port reset %ld\n",
> +				PTR_ERR(mrst->port));
> +
> +		return PTR_ERR(mrst->port);
> +	}
> +
> +	mrst->apb = devm_reset_control_get_shared(dev, "apb");
> +	if (IS_ERR(mrst->apb)) {
> +		if (PTR_ERR(mrst->apb) != -EPROBE_DEFER)
> +			dev_err(dev, "couldn't get apb reset\n");
> +
> +		return PTR_ERR(mrst->apb);
> +	}
> +
> +	reset_control_deassert(mrst->port);
> +	reset_control_deassert(mrst->apb);
> +
> +	phy_power_on(mp->phy);
> +
> +	ret = meson_pcie_init_clk(mp);
> +	if (ret) {
> +		dev_err(dev, "Init clock resources failed, %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = meson_pcie_get_mem(pdev, mp);
> +	if (ret) {
> +		dev_err(dev, "Get memory resource failed, %d\n", ret);
> +		return ret;
> +	}
> +
> +	platform_set_drvdata(pdev, mp);
> +
> +	ret = meson_add_pcie_port(mp, pdev);
> +	if (ret < 0) {
> +		dev_err(dev, "Add PCIE port failed, %d\n", ret);
> +		meson_pcie_deinit_clk(mp);
> +	}
> +
> +	return ret;
> +}
> +
> +static const struct of_device_id meson_pcie_of_match[] = {
> +	{
> +		.compatible = "amlogic,axg-pcie",
> +	},
> +	{},
> +};
> +
> +static struct platform_driver meson_pcie_driver = {
> +	.probe = meson_pcie_probe,
> +	.driver = {
> +		.name = "meson-pcie",
> +		.of_match_table = meson_pcie_of_match,
> +	},
> +};
> +
> +builtin_platform_driver(meson_pcie_driver);