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Date: Thu, 29 Feb 2024 15:24:04 +0100
From: Lorenzo Pieralisi <lpieralisi@kernel.org>
To: Minda Chen <minda.chen@starfivetech.com>
Cc: Conor Dooley <conor@kernel.org>,
	Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= <kw@linux.com>,
	Rob Herring <robh+dt@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Daire McNamara <daire.mcnamara@microchip.com>,
	Emil Renner Berthing <emil.renner.berthing@canonical.com>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-riscv@lists.infradead.org, linux-pci@vger.kernel.org,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Mason Huo <mason.huo@starfivetech.com>,
	Leyfoon Tan <leyfoon.tan@starfivetech.com>,
	Kevin Xie <kevin.xie@starfivetech.com>
Subject: Re: [PATCH v15,RESEND 21/23] PCI: starfive: Add JH7110 PCIe
 controller
Message-ID: <ZeCThFcD2HBg8/bx@lpieralisi>
References: <20240227103522.80915-1-minda.chen@starfivetech.com>
 <20240227103522.80915-22-minda.chen@starfivetech.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
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In-Reply-To: <20240227103522.80915-22-minda.chen@starfivetech.com>

On Tue, Feb 27, 2024 at 06:35:20PM +0800, Minda Chen wrote:
> Add StarFive JH7110 SoC PCIe controller platform driver codes, JH7110
> with PLDA host PCIe core.
> 
> Signed-off-by: Minda Chen <minda.chen@starfivetech.com>
> Co-developed-by: Kevin Xie <kevin.xie@starfivetech.com>
> Reviewed-by: Mason Huo <mason.huo@starfivetech.com>
> ---
>  MAINTAINERS                                 |   7 +
>  drivers/pci/controller/plda/Kconfig         |  12 +
>  drivers/pci/controller/plda/Makefile        |   1 +
>  drivers/pci/controller/plda/pcie-plda.h     |  71 ++-
>  drivers/pci/controller/plda/pcie-starfive.c | 473 ++++++++++++++++++++
>  5 files changed, 563 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/pci/controller/plda/pcie-starfive.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index fc9576e69a71..d3b0a0fb754f 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -17078,6 +17078,13 @@ S:	Maintained
>  F:	Documentation/devicetree/bindings/pci/socionext,uniphier-pcie*
>  F:	drivers/pci/controller/dwc/pcie-uniphier*
>  
> +PCIE DRIVER FOR STARFIVE JH71x0
> +M:	Kevin Xie <kevin.xie@starfivetech.com>
> +L:	linux-pci@vger.kernel.org
> +S:	Maintained
> +F:	Documentation/devicetree/bindings/pci/starfive*
> +F:	drivers/pci/controller/plda/pcie-starfive.c
> +
>  PCIE DRIVER FOR ST SPEAR13XX
>  M:	Pratyush Anand <pratyush.anand@gmail.com>
>  L:	linux-pci@vger.kernel.org
> diff --git a/drivers/pci/controller/plda/Kconfig b/drivers/pci/controller/plda/Kconfig
> index e54a82ee94f5..c0e14146d7e4 100644
> --- a/drivers/pci/controller/plda/Kconfig
> +++ b/drivers/pci/controller/plda/Kconfig
> @@ -15,4 +15,16 @@ config PCIE_MICROCHIP_HOST
>  	  Say Y here if you want kernel to support the Microchip AXI PCIe
>  	  Host Bridge driver.
>  
> +config PCIE_STARFIVE_HOST
> +	tristate "StarFive PCIe host controller"
> +	depends on PCI_MSI && OF
> +	depends on ARCH_STARFIVE || COMPILE_TEST
> +	select PCIE_PLDA_HOST
> +	help
> +	  Say Y here if you want to support the StarFive PCIe controller in
> +	  host mode. StarFive PCIe controller uses PLDA PCIe core.
> +
> +	  If you choose to build this driver as module it will be dynamically
> +	  linked and module will be called pcie-starfive.ko.
> +
>  endmenu
> diff --git a/drivers/pci/controller/plda/Makefile b/drivers/pci/controller/plda/Makefile
> index 4340ab007f44..0ac6851bed48 100644
> --- a/drivers/pci/controller/plda/Makefile
> +++ b/drivers/pci/controller/plda/Makefile
> @@ -1,3 +1,4 @@
>  # SPDX-License-Identifier: GPL-2.0
>  obj-$(CONFIG_PCIE_PLDA_HOST) += pcie-plda-host.o
>  obj-$(CONFIG_PCIE_MICROCHIP_HOST) += pcie-microchip-host.o
> +obj-$(CONFIG_PCIE_STARFIVE_HOST) += pcie-starfive.o
> diff --git a/drivers/pci/controller/plda/pcie-plda.h b/drivers/pci/controller/plda/pcie-plda.h
> index 7b69891700a4..04e385758a2f 100644
> --- a/drivers/pci/controller/plda/pcie-plda.h
> +++ b/drivers/pci/controller/plda/pcie-plda.h
> @@ -10,10 +10,20 @@
>  #define PLDA_MAX_NUM_MSI_IRQS			32
>  
>  /* PCIe Bridge Phy Regs */
> +#define GEN_SETTINGS				0x80
> +#define  RP_ENABLE				1
> +#define PCIE_PCI_IDS_DW1			0x9c
> +#define  IDS_CLASS_CODE_SHIFT			16
> +#define  REVISION_ID_MASK			GENMASK(7, 0)
> +#define  CLASS_CODE_ID_MASK			GENMASK(31, 8)
>  #define PCIE_PCI_IRQ_DW0			0xa8
>  #define  MSIX_CAP_MASK				BIT(31)
>  #define  NUM_MSI_MSGS_MASK			GENMASK(6, 4)
>  #define  NUM_MSI_MSGS_SHIFT			4
> +#define PCI_MISC				0xb4
> +#define  PHY_FUNCTION_DIS			BIT(15)
> +#define PCIE_WINROM				0xfc
> +#define  PREF_MEM_WIN_64_SUPPORT		BIT(3)
>  
>  #define IMASK_LOCAL				0x180
>  #define  DMA_END_ENGINE_0_MASK			0x00000000u
> @@ -65,6 +75,8 @@
>  #define ISTATUS_HOST				0x18c
>  #define IMSI_ADDR				0x190
>  #define ISTATUS_MSI				0x194
> +#define PMSG_SUPPORT_RX				0x3f0
> +#define  PMSG_LTR_SUPPORT			BIT(2)
>  
>  /* PCIe Master table init defines */
>  #define ATR0_PCIE_WIN0_SRCADDR_PARAM		0x600u
> @@ -86,6 +98,8 @@
>  #define  PCIE_TX_RX_INTERFACE			0x00000000u
>  #define  PCIE_CONFIG_INTERFACE			0x00000001u
>  
> +#define CONFIG_SPACE_ADDR_OFFSET		0x1000u
> +
>  #define ATR_ENTRY_SIZE				32
>  
>  enum plda_int_event {
> @@ -200,4 +214,59 @@ static inline void plda_set_default_msi(struct plda_msi *msi)
>  	msi->vector_phy = IMSI_ADDR;
>  	msi->num_vectors = PLDA_MAX_NUM_MSI_IRQS;
>  }
> -#endif
> +
> +static inline void plda_pcie_enable_root_port(struct plda_pcie_rp *plda)
> +{
> +	u32 value;
> +
> +	value = readl_relaxed(plda->bridge_addr + GEN_SETTINGS);
> +	value |= RP_ENABLE;
> +	writel_relaxed(value, plda->bridge_addr + GEN_SETTINGS);
> +}
> +
> +static inline void plda_pcie_set_standard_class(struct plda_pcie_rp *plda)
> +{
> +	u32 value;
> +
> +	/* set class code and reserve revision id */
> +	value = readl_relaxed(plda->bridge_addr + PCIE_PCI_IDS_DW1);
> +	value &= REVISION_ID_MASK;
> +	value |= (PCI_CLASS_BRIDGE_PCI << IDS_CLASS_CODE_SHIFT);
> +	writel_relaxed(value, plda->bridge_addr + PCIE_PCI_IDS_DW1);
> +}
> +
> +static inline void plda_pcie_set_pref_win_64bit(struct plda_pcie_rp *plda)
> +{
> +	u32 value;
> +
> +	value = readl_relaxed(plda->bridge_addr + PCIE_WINROM);
> +	value |= PREF_MEM_WIN_64_SUPPORT;
> +	writel_relaxed(value, plda->bridge_addr + PCIE_WINROM);
> +}

What does this do ?

> +static inline void plda_pcie_disable_ltr(struct plda_pcie_rp *plda)
> +{
> +	u32 value;
> +
> +	value = readl_relaxed(plda->bridge_addr + PMSG_SUPPORT_RX);
> +	value &= ~PMSG_LTR_SUPPORT;
> +	writel_relaxed(value, plda->bridge_addr + PMSG_SUPPORT_RX);
> +}
> +
> +static inline void plda_pcie_disable_func(struct plda_pcie_rp *plda)
> +{
> +	u32 value;
> +
> +	value = readl_relaxed(plda->bridge_addr + PCI_MISC);
> +	value |= PHY_FUNCTION_DIS;
> +	writel_relaxed(value, plda->bridge_addr + PCI_MISC);
> +}
> +
> +static inline void plda_pcie_write_rc_bar(struct plda_pcie_rp *plda, u64 val)
> +{
> +	void __iomem *addr = plda->bridge_addr + CONFIG_SPACE_ADDR_OFFSET;
> +
> +	writel_relaxed(lower_32_bits(val), addr + PCI_BASE_ADDRESS_0);
> +	writel_relaxed(upper_32_bits(val), addr + PCI_BASE_ADDRESS_1);
> +}
> +#endif /* _PCIE_PLDA_H */
> diff --git a/drivers/pci/controller/plda/pcie-starfive.c b/drivers/pci/controller/plda/pcie-starfive.c
> new file mode 100644
> index 000000000000..9bb9f0e29565
> --- /dev/null
> +++ b/drivers/pci/controller/plda/pcie-starfive.c
> @@ -0,0 +1,473 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * PCIe host controller driver for StarFive JH7110 Soc.
> + *
> + * Copyright (C) 2023 StarFive Technology Co., Ltd.
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/of_pci.h>
> +#include <linux/pci.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
> +#include <linux/reset.h>
> +#include "../../pci.h"
> +
> +#include "pcie-plda.h"
> +
> +#define PCIE_FUNC_NUM			4
> +
> +/* system control */
> +#define STG_SYSCON_PCIE0_BASE			0x48
> +#define STG_SYSCON_PCIE1_BASE			0x1f8
> +
> +#define STG_SYSCON_AR_OFFSET			0x78
> +#define STG_SYSCON_AXI4_SLVL_AR_MASK		GENMASK(22, 8)
> +#define STG_SYSCON_AXI4_SLVL_PHY_AR(x)		FIELD_PREP(GENMASK(20, 17), x)
> +#define STG_SYSCON_AW_OFFSET			0x7c
> +#define STG_SYSCON_AXI4_SLVL_AW_MASK		GENMASK(14, 0)
> +#define STG_SYSCON_AXI4_SLVL_PHY_AW(x)		FIELD_PREP(GENMASK(12, 9), x)
> +#define STG_SYSCON_CLKREQ			BIT(22)
> +#define STG_SYSCON_CKREF_SRC_MASK		GENMASK(19, 18)
> +#define STG_SYSCON_RP_NEP_OFFSET		0xe8
> +#define STG_SYSCON_K_RP_NEP			BIT(8)
> +#define STG_SYSCON_LNKSTA_OFFSET		0x170
> +#define DATA_LINK_ACTIVE			BIT(5)
> +
> +/* Parameters for the waiting for link up routine */
> +#define LINK_WAIT_MAX_RETRIES	10
> +#define LINK_WAIT_USLEEP_MIN	90000
> +#define LINK_WAIT_USLEEP_MAX	100000
> +
> +struct starfive_jh7110_pcie {
> +	struct plda_pcie_rp plda;
> +	struct reset_control *resets;
> +	struct clk_bulk_data *clks;
> +	struct regmap *reg_syscon;
> +	struct gpio_desc *power_gpio;
> +	struct gpio_desc *reset_gpio;
> +	struct phy *phy;
> +
> +	unsigned int stg_pcie_base;
> +	int num_clks;
> +};
> +
> +/*
> + * The BAR0/1 of bridge should be hidden during enumeration to
> + * avoid the sizing and resource allocation by PCIe core.

Please explain. This is what's preventing this driver to re-use
the PCI_HOST_COMMON infrastructure and it is unclear why.

> + */
> +static bool starfive_pcie_hide_rc_bar(struct pci_bus *bus, unsigned int devfn,
> +				      int offset)
> +{
> +	if (pci_is_root_bus(bus) && !devfn &&
> +	    (offset == PCI_BASE_ADDRESS_0 || offset == PCI_BASE_ADDRESS_1))
> +		return true;
> +
> +	return false;
> +}
> +
> +static int starfive_pcie_config_write(struct pci_bus *bus, unsigned int devfn,
> +				      int where, int size, u32 value)
> +{
> +	if (starfive_pcie_hide_rc_bar(bus, devfn, where))
> +		return PCIBIOS_SUCCESSFUL;
> +
> +	return pci_generic_config_write(bus, devfn, where, size, value);
> +}
> +
> +static int starfive_pcie_config_read(struct pci_bus *bus, unsigned int devfn,
> +				     int where, int size, u32 *value)
> +{
> +	if (starfive_pcie_hide_rc_bar(bus, devfn, where)) {
> +		*value = 0;
> +		return PCIBIOS_SUCCESSFUL;
> +	}
> +
> +	return pci_generic_config_read(bus, devfn, where, size, value);
> +}
> +
> +static int starfive_pcie_parse_dt(struct starfive_jh7110_pcie *pcie,
> +				  struct device *dev)
> +{
> +	int domain_nr;
> +
> +	pcie->num_clks = devm_clk_bulk_get_all(dev, &pcie->clks);
> +	if (pcie->num_clks < 0)
> +		return dev_err_probe(dev, pcie->num_clks,
> +				     "failed to get pcie clocks\n");
> +
> +	pcie->resets = devm_reset_control_array_get_exclusive(dev);
> +	if (IS_ERR(pcie->resets))
> +		return dev_err_probe(dev, PTR_ERR(pcie->resets),
> +				     "failed to get pcie resets");
> +
> +	pcie->reg_syscon =
> +		syscon_regmap_lookup_by_phandle(dev->of_node,
> +						"starfive,stg-syscon");
> +
> +	if (IS_ERR(pcie->reg_syscon))
> +		return dev_err_probe(dev, PTR_ERR(pcie->reg_syscon),
> +				     "failed to parse starfive,stg-syscon\n");
> +
> +	pcie->phy = devm_phy_optional_get(dev, NULL);
> +	if (IS_ERR(pcie->phy))
> +		return dev_err_probe(dev, PTR_ERR(pcie->phy),
> +				     "failed to get pcie phy\n");
> +
> +	domain_nr = of_get_pci_domain_nr(dev->of_node);
> +
> +	if (domain_nr < 0 || domain_nr > 1)
> +		return dev_err_probe(dev, -ENODEV,
> +				     "failed to get valid pcie domain\n");
> +
> +	if (domain_nr == 0)
> +		pcie->stg_pcie_base = STG_SYSCON_PCIE0_BASE;
> +	else
> +		pcie->stg_pcie_base = STG_SYSCON_PCIE1_BASE;

I don't agree with this. The domain number is a software allocated
value attached to a controller. It is written nowhere that you can't
swap them and leave this code path broken.

> +	pcie->reset_gpio = devm_gpiod_get_optional(dev, "perst",
> +						   GPIOD_OUT_HIGH);
> +	if (IS_ERR(pcie->reset_gpio))
> +		return dev_err_probe(dev, PTR_ERR(pcie->reset_gpio),
> +				     "failed to get perst-gpio\n");
> +
> +	pcie->power_gpio = devm_gpiod_get_optional(dev, "enable",
> +						   GPIOD_OUT_LOW);
> +	if (IS_ERR(pcie->power_gpio))
> +		return dev_err_probe(dev, PTR_ERR(pcie->power_gpio),
> +				     "failed to get power-gpio\n");
> +
> +	return 0;
> +}
> +
> +static struct pci_ops starfive_pcie_ops = {
> +	.map_bus	= plda_pcie_map_bus,

It looks like this is an ECAM driver with the read/config quirks
for read/write in the method below. Please explain why they are needed.

> +	.read           = starfive_pcie_config_read,
> +	.write          = starfive_pcie_config_write,
> +};
> +
> +static int starfive_pcie_clk_rst_init(struct starfive_jh7110_pcie *pcie)
> +{
> +	struct device *dev = pcie->plda.dev;
> +	int ret;
> +
> +	ret = clk_bulk_prepare_enable(pcie->num_clks, pcie->clks);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to enable clocks\n");
> +
> +	ret = reset_control_deassert(pcie->resets);
> +	if (ret) {
> +		clk_bulk_disable_unprepare(pcie->num_clks, pcie->clks);
> +		dev_err_probe(dev, ret, "failed to deassert resets\n");
> +	}
> +
> +	return ret;
> +}
> +
> +static void starfive_pcie_clk_rst_deinit(struct starfive_jh7110_pcie *pcie)
> +{
> +	reset_control_assert(pcie->resets);
> +	clk_bulk_disable_unprepare(pcie->num_clks, pcie->clks);
> +}
> +
> +static bool starfive_pcie_link_up(struct plda_pcie_rp *plda)
> +{
> +	struct starfive_jh7110_pcie *pcie =
> +		container_of(plda, struct starfive_jh7110_pcie, plda);
> +	int ret;
> +	u32 stg_reg_val;
> +
> +	ret = regmap_read(pcie->reg_syscon,
> +			  pcie->stg_pcie_base + STG_SYSCON_LNKSTA_OFFSET,
> +			  &stg_reg_val);
> +	if (ret) {
> +		dev_err(pcie->plda.dev, "failed to read link status\n");
> +		return false;
> +	}
> +
> +	return !!(stg_reg_val & DATA_LINK_ACTIVE);
> +}
> +
> +static int starfive_pcie_host_wait_for_link(struct starfive_jh7110_pcie *pcie)
> +{
> +	int retries;
> +
> +	/* Check if the link is up or not */
> +	for (retries = 0; retries < LINK_WAIT_MAX_RETRIES; retries++) {
> +		if (starfive_pcie_link_up(&pcie->plda)) {
> +			dev_info(pcie->plda.dev, "port link up\n");
> +			return 0;
> +		}
> +		usleep_range(LINK_WAIT_USLEEP_MIN, LINK_WAIT_USLEEP_MAX);
> +	}
> +
> +	return -ETIMEDOUT;
> +}
> +
> +static int starfive_pcie_enable_phy(struct device *dev,
> +				    struct starfive_jh7110_pcie *pcie)
> +{
> +	int ret;
> +
> +	if (!pcie->phy)
> +		return 0;
> +
> +	ret = phy_init(pcie->phy);
> +	if (ret)
> +		return dev_err_probe(dev, ret,
> +				     "failed to initialize pcie phy\n");
> +
> +	ret = phy_set_mode(pcie->phy, PHY_MODE_PCIE);
> +	if (ret) {
> +		dev_err_probe(dev, ret, "failed to set pcie mode\n");
> +		goto err_phy_on;
> +	}
> +
> +	ret = phy_power_on(pcie->phy);
> +	if (ret) {
> +		dev_err_probe(dev, ret, "failed to power on pcie phy\n");
> +		goto err_phy_on;
> +	}
> +
> +	return 0;
> +
> +err_phy_on:
> +	phy_exit(pcie->phy);
> +	return ret;
> +}
> +
> +static void starfive_pcie_disable_phy(struct starfive_jh7110_pcie *pcie)
> +{
> +	phy_power_off(pcie->phy);
> +	phy_exit(pcie->phy);
> +}
> +
> +static void starfive_pcie_host_deinit(struct plda_pcie_rp *plda)
> +{
> +	struct starfive_jh7110_pcie *pcie =
> +		container_of(plda, struct starfive_jh7110_pcie, plda);
> +
> +	starfive_pcie_clk_rst_deinit(pcie);
> +	if (pcie->power_gpio)
> +		gpiod_set_value_cansleep(pcie->power_gpio, 0);
> +	starfive_pcie_disable_phy(pcie);
> +}
> +
> +static int starfive_pcie_host_init(struct plda_pcie_rp *plda)
> +{
> +	struct starfive_jh7110_pcie *pcie =
> +		container_of(plda, struct starfive_jh7110_pcie, plda);
> +	struct device *dev = plda->dev;
> +	int ret;
> +	int i;
> +
> +	ret = starfive_pcie_enable_phy(dev, pcie);
> +	if (ret)
> +		return ret;
> +
> +	regmap_update_bits(pcie->reg_syscon,
> +			   pcie->stg_pcie_base + STG_SYSCON_RP_NEP_OFFSET,
> +			   STG_SYSCON_K_RP_NEP, STG_SYSCON_K_RP_NEP);
> +
> +	regmap_update_bits(pcie->reg_syscon,
> +			   pcie->stg_pcie_base + STG_SYSCON_AW_OFFSET,
> +			   STG_SYSCON_CKREF_SRC_MASK,
> +			   FIELD_PREP(STG_SYSCON_CKREF_SRC_MASK, 2));
> +
> +	regmap_update_bits(pcie->reg_syscon,
> +			   pcie->stg_pcie_base + STG_SYSCON_AW_OFFSET,
> +			   STG_SYSCON_CLKREQ, STG_SYSCON_CLKREQ);
> +
> +	ret = starfive_pcie_clk_rst_init(pcie);
> +	if (ret)
> +		return ret;
> +
> +	if (pcie->power_gpio)
> +		gpiod_set_value_cansleep(pcie->power_gpio, 1);
> +
> +	if (pcie->reset_gpio)
> +		gpiod_set_value_cansleep(pcie->reset_gpio, 1);
> +
> +	/* Disable physical functions except #0 */
> +	for (i = 1; i < PCIE_FUNC_NUM; i++) {
> +		regmap_update_bits(pcie->reg_syscon,
> +				   pcie->stg_pcie_base + STG_SYSCON_AR_OFFSET,
> +				   STG_SYSCON_AXI4_SLVL_AR_MASK,
> +				   STG_SYSCON_AXI4_SLVL_PHY_AR(i));
> +
> +		regmap_update_bits(pcie->reg_syscon,
> +				   pcie->stg_pcie_base + STG_SYSCON_AW_OFFSET,
> +				   STG_SYSCON_AXI4_SLVL_AW_MASK,
> +				   STG_SYSCON_AXI4_SLVL_PHY_AW(i));
> +
> +		plda_pcie_disable_func(plda);
> +	}
> +
> +	regmap_update_bits(pcie->reg_syscon,
> +			   pcie->stg_pcie_base + STG_SYSCON_AR_OFFSET,
> +			   STG_SYSCON_AXI4_SLVL_AR_MASK, 0);
> +	regmap_update_bits(pcie->reg_syscon,
> +			   pcie->stg_pcie_base + STG_SYSCON_AW_OFFSET,
> +			   STG_SYSCON_AXI4_SLVL_AW_MASK, 0);
> +
> +	plda_pcie_enable_root_port(plda);
> +	plda_pcie_write_rc_bar(plda, 0);
> +
> +	/* PCIe PCI Standard Configuration Identification Settings. */
> +	plda_pcie_set_standard_class(plda);
> +
> +	/*
> +	 * The LTR message forwarding of PCIe Message Reception was set by core

"LTR message forwarding of PCIe Message Reception".

What is this referring to ?

Thanks,
Lorenzo

> +	 * as default, but the forward id & addr are also need to be reset.
> +	 * If we do not disable LTR message forwarding here, or set a legal
> +	 * forwarding address, the kernel will get stuck after the driver probe.
> +	 * To workaround, disable the LTR message forwarding support on
> +	 * PCIe Message Reception.
> +	 */
> +	plda_pcie_disable_ltr(plda);
> +
> +	/* Prefetchable memory window 64-bit addressing support */
> +	plda_pcie_set_pref_win_64bit(plda);
> +
> +	/*
> +	 * Ensure that PERST has been asserted for at least 100 ms,
> +	 * the sleep value is T_PVPERL from PCIe CEM spec r2.0 (Table 2-4)
> +	 */
> +	msleep(100);
> +	if (pcie->reset_gpio)
> +		gpiod_set_value_cansleep(pcie->reset_gpio, 0);
> +
> +	/*
> +	 * With a Downstream Port (<=5GT/s), software must wait a minimum
> +	 * of 100ms following exit from a conventional reset before
> +	 * sending a configuration request to the device.
> +	 */
> +	msleep(PCIE_RESET_CONFIG_DEVICE_WAIT_MS);
> +
> +	if (starfive_pcie_host_wait_for_link(pcie))
> +		dev_info(dev, "port link down\n");
> +
> +	return 0;
> +}
> +
> +static const struct plda_pcie_host_ops sf_host_ops = {
> +	.host_init = starfive_pcie_host_init,
> +	.host_deinit = starfive_pcie_host_deinit,
> +};
> +
> +static const struct plda_event stf_pcie_event = {
> +	.intx_event = EVENT_PM_MSI_INT_INTX,
> +	.msi_event  = EVENT_PM_MSI_INT_MSI
> +};
> +
> +static int starfive_pcie_probe(struct platform_device *pdev)
> +{
> +	struct starfive_jh7110_pcie *pcie;
> +	struct device *dev = &pdev->dev;
> +	struct plda_pcie_rp *plda;
> +	int ret;
> +
> +	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
> +	if (!pcie)
> +		return -ENOMEM;
> +
> +	plda = &pcie->plda;
> +	plda->dev = dev;
> +
> +	ret = starfive_pcie_parse_dt(pcie, dev);
> +	if (ret)
> +		return ret;
> +
> +	plda->host_ops = &sf_host_ops;
> +	plda->num_events = PLDA_MAX_EVENT_NUM;
> +	/* mask doorbell event */
> +	plda->events_bitmap = GENMASK(PLDA_INT_EVENT_NUM - 1, 0)
> +			     & ~BIT(PLDA_AXI_DOORBELL)
> +			     & ~BIT(PLDA_PCIE_DOORBELL);
> +	plda->events_bitmap <<= PLDA_NUM_DMA_EVENTS;
> +	ret = plda_pcie_host_init(&pcie->plda, &starfive_pcie_ops,
> +				  &stf_pcie_event);
> +	if (ret)
> +		return ret;
> +
> +	pm_runtime_enable(&pdev->dev);
> +	pm_runtime_get_sync(&pdev->dev);
> +	platform_set_drvdata(pdev, pcie);
> +
> +	return 0;
> +}
> +
> +static void starfive_pcie_remove(struct platform_device *pdev)
> +{
> +	struct starfive_jh7110_pcie *pcie = platform_get_drvdata(pdev);
> +
> +	pm_runtime_put(&pdev->dev);
> +	pm_runtime_disable(&pdev->dev);
> +	plda_pcie_host_deinit(&pcie->plda);
> +	platform_set_drvdata(pdev, NULL);
> +}
> +
> +static int starfive_pcie_suspend_noirq(struct device *dev)
> +{
> +	struct starfive_jh7110_pcie *pcie = dev_get_drvdata(dev);
> +
> +	clk_bulk_disable_unprepare(pcie->num_clks, pcie->clks);
> +	starfive_pcie_disable_phy(pcie);
> +
> +	return 0;
> +}
> +
> +static int starfive_pcie_resume_noirq(struct device *dev)
> +{
> +	struct starfive_jh7110_pcie *pcie = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = starfive_pcie_enable_phy(dev, pcie);
> +	if (ret)
> +		return ret;
> +
> +	ret = clk_bulk_prepare_enable(pcie->num_clks, pcie->clks);
> +	if (ret) {
> +		dev_err(dev, "failed to enable clocks\n");
> +		starfive_pcie_disable_phy(pcie);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops starfive_pcie_pm_ops = {
> +	NOIRQ_SYSTEM_SLEEP_PM_OPS(starfive_pcie_suspend_noirq,
> +				  starfive_pcie_resume_noirq)
> +};
> +
> +static const struct of_device_id starfive_pcie_of_match[] = {
> +	{ .compatible = "starfive,jh7110-pcie", },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, starfive_pcie_of_match);
> +
> +static struct platform_driver starfive_pcie_driver = {
> +	.driver = {
> +		.name = "pcie-starfive",
> +		.of_match_table = of_match_ptr(starfive_pcie_of_match),
> +		.pm = pm_sleep_ptr(&starfive_pcie_pm_ops),
> +	},
> +	.probe = starfive_pcie_probe,
> +	.remove_new = starfive_pcie_remove,
> +};
> +module_platform_driver(starfive_pcie_driver);
> +
> +MODULE_DESCRIPTION("StarFive JH7110 PCIe host driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.17.1
> 
> 
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