[PATCH v2 1/3] starfive: pci: Add StarFive JH7110 pcie driver

Pali Rohár pali at kernel.org
Fri Mar 10 18:42:36 CET 2023


On Friday 10 March 2023 18:36:44 Minda Chen wrote:
> On 2023/3/8 15:31, Pali Rohár wrote:
> > Hello! See few comments below.
> > 
> > On Wednesday 08 March 2023 13:48:31 Minda Chen wrote:
> >> From: Mason Huo <mason.huo at starfivetech.com>
> >> 
> >> Add pcie driver for StarFive JH7110, the driver depends on
> >> starfive gpio, pinctrl, clk and reset driver to do init.
> >> 
> >> Several devices are tested:
> >> a) M.2 NVMe SSD
> >> b) Realtek 8169 Ethernet adapter.
> >> 
> >> Signed-off-by: Mason Huo <mason.huo at starfivetech.com>
> >> Signed-off-by: Minda Chen <minda.chen at starfivetech.com>
> >> ---
> >>  drivers/pci/Kconfig                |  11 +
> >>  drivers/pci/Makefile               |   1 +
> >>  drivers/pci/pcie_starfive_jh7110.c | 478 +++++++++++++++++++++++++++++
> >>  3 files changed, 490 insertions(+)
> >>  create mode 100644 drivers/pci/pcie_starfive_jh7110.c
> >> 
> >> diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
> >> index ef328d2652..e7b0ff5bc3 100644
> >> --- a/drivers/pci/Kconfig
> >> +++ b/drivers/pci/Kconfig
> >> @@ -374,4 +374,15 @@ config PCIE_UNIPHIER
> >>  	  Say Y here if you want to enable PCIe controller support on
> >>  	  UniPhier SoCs.
> >>  
> >> +config PCIE_STARFIVE_JH7110
> >> +	bool "Enable Starfive JH7110 PCIe driver"
> >> +	depends on STARFIVE_JH7110
> >> +	depends on PINCTRL_STARFIVE_JH7110
> >> +	depends on CLK_JH7110
> >> +	depends on RESET_JH7110
> >> +	default y
> >> +	help
> >> +	  Say Y here if you want to enable PCIe controller support on
> >> +	  StarFive JH7110 SoC.
> >> +
> >>  endif
> >> diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
> >> index 49506e7ba5..bbe3323bb5 100644
> >> --- a/drivers/pci/Makefile
> >> +++ b/drivers/pci/Makefile
> >> @@ -49,3 +49,4 @@ obj-$(CONFIG_PCI_OCTEONTX) += pci_octeontx.o
> >>  obj-$(CONFIG_PCIE_OCTEON) += pcie_octeon.o
> >>  obj-$(CONFIG_PCIE_DW_SIFIVE) += pcie_dw_sifive.o
> >>  obj-$(CONFIG_PCIE_UNIPHIER) += pcie_uniphier.o
> >> +obj-$(CONFIG_PCIE_STARFIVE_JH7110) += pcie_starfive_jh7110.o
> >> diff --git a/drivers/pci/pcie_starfive_jh7110.c b/drivers/pci/pcie_starfive_jh7110.c
> >> new file mode 100644
> >> index 0000000000..5ccef1ef02
> >> --- /dev/null
> >> +++ b/drivers/pci/pcie_starfive_jh7110.c
> >> @@ -0,0 +1,478 @@
> >> +// SPDX-License-Identifier: GPL-2.0+
> >> +/*
> >> + * StarFive PLDA PCIe host controller driver
> >> + *
> >> + * Copyright (c) 2023 Starfive, Inc.
> >> + * Author: Mason Huo <mason.huo at starfivetech.com>
> >> + *
> >> + */
> >> +
> >> +#include <common.h>
> >> +#include <clk.h>
> >> +#include <dm.h>
> >> +#include <generic-phy.h>
> >> +#include <pci.h>
> >> +#include <power-domain.h>
> >> +#include <regmap.h>
> >> +#include <reset.h>
> >> +#include <syscon.h>
> >> +#include <asm/global_data.h>
> >> +#include <asm/io.h>
> >> +#include <asm-generic/gpio.h>
> >> +#include <dm/device_compat.h>
> >> +#include <dm/pinctrl.h>
> >> +#include <linux/delay.h>
> >> +#include <linux/iopoll.h>
> >> +#include <power/regulator.h>
> >> +
> >> +DECLARE_GLOBAL_DATA_PTR;
> >> +
> >> +#define GEN_SETTINGS			0x80
> >> +#define PCIE_PCI_IDS			0x9C
> >> +#define PCIE_WINROM			0xFC
> >> +#define PMSG_SUPPORT_RX			0x3F0
> >> +#define PCI_MISC			0xB4
> >> +
> >> +#define PLDA_EP_ENABLE			0
> >> +#define PLDA_RP_ENABLE			1
> >> +
> >> +#define IDS_REVISION_ID			0x02
> >> +#define IDS_PCI_TO_PCI_BRIDGE		0x060400
> >> +#define IDS_CLASS_CODE_SHIFT		8
> > 
> > Please do not duplicate standard PCI macros and constants. In U-Boot
> > they are already available in include/pci_ids.h header file.
> > 
> ok
> >> +#define PREF_MEM_WIN_64_SUPPORT		BIT(3)
> >> +#define PMSG_LTR_SUPPORT		BIT(2)
> >> +#define PLDA_FUNCTION_DIS		BIT(15)
> >> +#define PLDA_FUNC_NUM			4
> >> +#define PLDA_PHY_FUNC_SHIFT		9
> >> +
> >> +#define XR3PCI_ATR_AXI4_SLV0		0x800
> >> +#define XR3PCI_ATR_SRC_ADDR_LOW		0x0
> >> +#define XR3PCI_ATR_SRC_ADDR_HIGH	0x4
> >> +#define XR3PCI_ATR_TRSL_ADDR_LOW	0x8
> >> +#define XR3PCI_ATR_TRSL_ADDR_HIGH	0xc
> >> +#define XR3PCI_ATR_TRSL_PARAM		0x10
> >> +#define XR3PCI_ATR_TABLE_OFFSET		0x20
> >> +#define XR3PCI_ATR_MAX_TABLE_NUM	8
> >> +
> >> +#define XR3PCI_ATR_SRC_WIN_SIZE_SHIFT	1
> >> +#define XR3PCI_ATR_SRC_ADDR_MASK	GENMASK(31, 12)
> >> +#define XR3PCI_ATR_TRSL_ADDR_MASK	GENMASK(31, 12)
> >> +#define XR3_PCI_ECAM_SIZE		28
> >> +#define XR3PCI_ATR_TRSL_DIR		BIT(22)
> >> +/* IDs used in the XR3PCI_ATR_TRSL_PARAM */
> >> +#define XR3PCI_ATR_TRSLID_PCIE_MEMORY	0x0
> >> +#define XR3PCI_ATR_TRSLID_PCIE_CONFIG	0x1
> >> +
> >> +#define ECAM_BUS_SHIFT			20
> >> +#define ECAM_DEV_SHIFT			15
> >> +#define ECAM_FUNC_SHIFT			12
> > 
> > Please do not implement duplicate PCIe ECAM code. U-Boot and also Linux
> > kernel already provides PCIE_ECAM_OFFSET() macro.
> > 
> >> +/* Secondary bus number offset in config space */
> >> +#define PCI_SECONDARY_BUS		0x19
> > 
> > Unused.
> > 
> ok
> >> +
> >> +/* system control */
> >> +#define STG_SYSCON_K_RP_NEP_MASK		BIT(8)
> >> +#define STG_SYSCON_AXI4_SLVL_ARFUNC_MASK	GENMASK(22, 8)
> >> +#define STG_SYSCON_AXI4_SLVL_ARFUNC_SHIFT	8
> >> +#define STG_SYSCON_AXI4_SLVL_AWFUNC_MASK	GENMASK(14, 0)
> >> +#define STG_SYSCON_CLKREQ_MASK			BIT(22)
> >> +#define STG_SYSCON_CKREF_SRC_SHIFT		18
> >> +#define STG_SYSCON_CKREF_SRC_MASK		GENMASK(19, 18)
> >> +
> >> +struct starfive_pcie {
> >> +	struct udevice *dev;
> >> +
> >> +	void __iomem *reg_base;
> >> +	void __iomem *cfg_base;
> >> +
> >> +	struct regmap *regmap;
> >> +	u32 stg_arfun;
> >> +	u32 stg_awfun;
> >> +	u32 stg_rp_nep;
> >> +
> >> +	struct clk_bulk	clks;
> >> +	struct reset_ctl_bulk	rsts;
> >> +
> >> +	int atr_table_num;
> >> +	int first_busno;
> >> +};
> >> +
> >> +static int starfive_pcie_addr_valid(pci_dev_t bdf, int first_busno)
> >> +{
> >> +	if ((PCI_BUS(bdf) == first_busno) && (PCI_DEV(bdf) > 0))
> >> +		return 0;
> >> +	if ((PCI_BUS(bdf) == first_busno + 1) && (PCI_DEV(bdf) > 0))
> >> +		return 0;
> > 
> > If fisrt_busno is the bus of the root port then first_busno+1 does not
> > have to bus of the PCIe device on the other end of the link from the
> > root port. See for example pci_mvebu.c how this logic is handled.
> > You probably want to also limit access to non-zero function of root port
> > unless you have multifunction root-port device.
> > 
> root port limitation can follow the  pci_mvebu.c

It can follow, but question is why it should follow pci_mvebu.c. Marvell
PCIe controller does not use ECAM, instead it uses Intel PCI conf1
mechanism and moreover it contains HW bugs which are workarounded in
that filter code.

> >> +
> >> +	return 1;
> >> +}
> >> +
> >> +static int starfive_pcie_off_conf(pci_dev_t bdf, uint offset)
> >> +{
> >> +	unsigned int bus = PCI_BUS(bdf);
> >> +	unsigned int dev = PCI_DEV(bdf);
> >> +	unsigned int func = PCI_FUNC(bdf);
> >> +
> >> +	return (bus << ECAM_BUS_SHIFT) | (dev << ECAM_DEV_SHIFT) |
> >> +			(func << ECAM_FUNC_SHIFT) | offset;
> >> +}
> >> +
> >> +static bool starfive_pcie_hide_rc_bar(pci_dev_t bdf, int offset)
> >> +{
> >> +	/* Only root port 1 is in use */
> >> +	if ((PCI_BUS(bdf) == 0) &&
> > 
> > This looks like an incorrect check for the bus of he root port.
> > See for example pci_mvebu.c where logic should be correct.
> > 
> > I guess you wanted to use: PCI_BUS(bdf)-dev_seq(udev)
> > [1] This is a work around method. Our PCIe support 64bit. But the config
> space is 16KB. If no limitation here, uboot will set high 32 bit base address to 0xfffffff after init.

I just do not understand. BAR configures PCIe MEM space mapping and it
is fully independent of the PCIe config space. I do not see reason for
limitation.

> But this will make kernel pcie failed. This value will be not cleared.
> While kernel read the base address first. kernel pcie can not work.
> And our IC we can not reset the PCIe to clear this value.
> I dont know how to fix it expcept this method.

Well, this sounds like a bug in kernel, which should be fixed or at
least reported.

And if in the u-boot is workaround for particular kernel bug then it
should be properly documented with information in which kernel version
was bug fixed. Otherwise u-boot code stay in non-maintenanceble state.

> >> +	    (offset == PCI_BASE_ADDRESS_0 || offset == PCI_BASE_ADDRESS_1))
> >> +		return true;
> >> +
> >> +	return false;
> >> +}
> >> +
> >> +static int starfive_pcie_conf_address(const struct udevice *udev, pci_dev_t bdf,
> >> +				      uint offset, void **paddr)
> >> +{
> >> +	struct starfive_pcie *priv = dev_get_priv(udev);
> >> +	int where = starfive_pcie_off_conf(bdf, offset);
> >> +
> >> +	if (!starfive_pcie_addr_valid(bdf, priv->first_busno))
> >> +		return -EINVAL;
> > 
> > Is this check needed? Does it mean that ECAM returns bogus information
> > for disconnected devices, that it needs to be manually filtered? (Which
> > is against PCIe spec).
> > 
> I found nvme device can not work if the non-zero function of root port
> without limitation. But I will try to fix it. Maybe I can remove this.

So you have multifunction root port device (if you are talking about
non-zero function)? And what does it mean that NVMe device cannot work?
Can you connect your device to second function of root port if it works?

> >> +
> >> +	*paddr = (void *)(priv->cfg_base + where);
> >> +	return 0;
> >> +}
> >> +
> >> +static int starfive_pcie_config_read(const struct udevice *udev, pci_dev_t bdf,
> >> +				     uint offset, ulong *valuep,
> >> +				     enum pci_size_t size)
> >> +{
> >> +	/* Make sure the LAST TLP is finished, before reading vendor ID. */
> >> +	if (offset == PCI_VENDOR_ID)
> >> +		mdelay(20);
> > 
> > This looks strange. There is some bug / errata that reading vendor id
> > from ECAM does not work correctly?
> > 
> I will remove this. It is not a errata of reading the vendor ID. 
> >> +
> >> +	return pci_generic_mmap_read_config(udev, starfive_pcie_conf_address,
> >> +					    bdf, offset, valuep, size);
> >> +}
> >> +
> >> +int starfive_pcie_config_write(struct udevice *udev, pci_dev_t bdf,
> >> +			       uint offset, ulong value,
> >> +			       enum pci_size_t size)
> >> +{
> >> +	if (starfive_pcie_hide_rc_bar(bdf, offset))
> >> +		return 0;
> > 
> > Why you are ignoring writes to some offset, but not ignoring reads? And
> > ignoring results in no-error (return value 0)?
> >The same as [1]

But this does not explain why is result ignored. I'm just lost what is
aim or expected result here.

> >> +
> >> +	return pci_generic_mmap_write_config(udev, starfive_pcie_conf_address,
> >> +					     bdf, offset, value, size);
> >> +}
> >> +
> >> +static int starfive_pcie_set_atr_entry(struct starfive_pcie *priv, phys_addr_t src_addr,
> >> +				       phys_addr_t trsl_addr, size_t window_size,
> >> +				       int trsl_param)
> >> +{
> >> +	void __iomem *base =
> >> +		priv->reg_base + XR3PCI_ATR_AXI4_SLV0;
> >> +
> >> +	/* Support AXI4 Slave 0 Address Translation Tables 0-7. */
> >> +	if (priv->atr_table_num >= XR3PCI_ATR_MAX_TABLE_NUM) {
> >> +		dev_err(priv->dev, "ATR table number %d exceeds max num\n",
> >> +			priv->atr_table_num);
> >> +		return -EINVAL;
> >> +	}
> >> +	base +=  XR3PCI_ATR_TABLE_OFFSET * priv->atr_table_num;
> >> +	priv->atr_table_num++;
> >> +
> >> +	/* X3PCI_ATR_SRC_ADDR_LOW:
> >> +	 *   - bit 0: enable entry,
> >> +	 *   - bits 1-6: ATR window size: total size in bytes: 2^(ATR_WSIZE + 1)
> >> +	 *   - bits 7-11: reserved
> >> +	 *   - bits 12-31: start of source address
> >> +	 */
> >> +	writel((lower_32_bits(src_addr) & XR3PCI_ATR_SRC_ADDR_MASK) |
> >> +			(fls(window_size) - 1) << XR3PCI_ATR_SRC_WIN_SIZE_SHIFT | 1,
> >> +			base + XR3PCI_ATR_SRC_ADDR_LOW);
> >> +	writel(upper_32_bits(src_addr), base + XR3PCI_ATR_SRC_ADDR_HIGH);
> >> +	writel((lower_32_bits(trsl_addr) & XR3PCI_ATR_TRSL_ADDR_MASK),
> >> +	       base + XR3PCI_ATR_TRSL_ADDR_LOW);
> >> +	writel(upper_32_bits(trsl_addr), base + XR3PCI_ATR_TRSL_ADDR_HIGH);
> >> +	writel(trsl_param, base + XR3PCI_ATR_TRSL_PARAM);
> >> +
> >> +	dev_dbg(priv->dev, "ATR entry: 0x%010llx %s 0x%010llx [0x%010llx] (param: 0x%06x)\n",
> >> +		src_addr, (trsl_param & XR3PCI_ATR_TRSL_DIR) ? "<-" : "->",
> >> +		trsl_addr, (u64)window_size, trsl_param);
> >> +	return 0;
> >> +}
> >> +
> >> +static int starfive_pcie_atr_init(struct starfive_pcie *priv)
> >> +{
> >> +	struct udevice *ctlr = pci_get_controller(priv->dev);
> >> +	struct pci_controller *hose = dev_get_uclass_priv(ctlr);
> >> +	int i, ret;
> >> +
> >> +	/* As the two host bridges in JH7110 soc have the same default
> >> +	 * address translation table, this cause the second root port can't
> >> +	 * access it's host bridge config space correctly.
> >> +	 * To workaround, config the ATR of host bridge config space by SW.
> >> +	 */
> >> +
> >> +	ret = starfive_pcie_set_atr_entry(priv,
> >> +					  (phys_addr_t)priv->cfg_base,
> >> +					  0,
> >> +					  1 << XR3_PCI_ECAM_SIZE,
> >> +					  XR3PCI_ATR_TRSLID_PCIE_CONFIG);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	for (i = 0; i < hose->region_count; i++) {
> >> +		if (hose->regions[i].flags == PCI_REGION_SYS_MEMORY)
> >> +			continue;
> >> +
> >> +		/* Only support identity mappings. */
> >> +		if (hose->regions[i].bus_start !=
> >> +		    hose->regions[i].phys_start)
> >> +			return -EINVAL;
> >> +
> >> +		ret = starfive_pcie_set_atr_entry(priv,
> >> +						  hose->regions[i].phys_start,
> >> +						  hose->regions[i].bus_start,
> >> +						  hose->regions[i].size,
> >> +						  XR3PCI_ATR_TRSLID_PCIE_MEMORY);
> >> +		if (ret)
> >> +			return ret;
> >> +	}
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int starfive_pcie_get_syscon(struct udevice *dev)
> >> +{
> >> +	struct starfive_pcie *priv = dev_get_priv(dev);
> >> +	struct udevice *syscon;
> >> +	struct ofnode_phandle_args syscfg_phandle;
> >> +	u32 cells[4];
> >> +	int ret;
> >> +
> >> +	/* get corresponding syscon phandle */
> >> +	ret = dev_read_phandle_with_args(dev, "starfive,stg-syscon", NULL, 0, 0,
> >> +					 &syscfg_phandle);
> >> +
> >> +	if (ret < 0) {
> >> +		dev_err(dev, "Can't get syscfg phandle: %d\n", ret);
> >> +		return ret;
> >> +	}
> >> +
> >> +	ret = uclass_get_device_by_ofnode(UCLASS_SYSCON, syscfg_phandle.node,
> >> +					  &syscon);
> >> +	if (ret) {
> >> +		dev_err(dev, "Unable to find syscon device (%d)\n", ret);
> >> +		return ret;
> >> +	}
> >> +
> >> +	priv->regmap = syscon_get_regmap(syscon);
> >> +	if (!priv->regmap) {
> >> +		dev_err(dev, "Unable to find regmap\n");
> >> +		return -ENODEV;
> >> +	}
> >> +
> >> +	/* get syscon register offset */
> >> +	ret = dev_read_u32_array(dev, "starfive,stg-syscon",
> >> +				 cells, ARRAY_SIZE(cells));
> >> +	if (ret) {
> >> +		dev_err(dev, "Get syscon register err %d\n", ret);
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	dev_dbg(dev, "Get syscon values: %x, %x, %x\n",
> >> +		cells[1], cells[2], cells[3]);
> >> +	priv->stg_arfun = cells[1];
> >> +	priv->stg_awfun = cells[2];
> >> +	priv->stg_rp_nep = cells[3];
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int starfive_pcie_parse_dt(struct udevice *dev)
> >> +{
> >> +	struct starfive_pcie *priv = dev_get_priv(dev);
> >> +	int ret;
> >> +
> >> +	priv->reg_base = (void *)dev_read_addr_name(dev, "reg");
> >> +	if (priv->reg_base == (void __iomem *)FDT_ADDR_T_NONE) {
> >> +		dev_err(dev, "Missing required reg address range\n");
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	priv->cfg_base = (void *)dev_read_addr_name(dev, "config");
> >> +	if (priv->cfg_base == (void __iomem *)FDT_ADDR_T_NONE) {
> >> +		dev_err(dev, "Missing required config address range");
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	ret = starfive_pcie_get_syscon(dev);
> >> +	if (ret) {
> >> +		dev_err(dev, "Can't get syscon: %d\n", ret);
> >> +		return ret;
> >> +	}
> >> +
> >> +	ret = reset_get_bulk(dev, &priv->rsts);
> >> +	if (ret) {
> >> +		dev_err(dev, "Can't get reset: %d\n", ret);
> >> +		return ret;
> >> +	}
> >> +
> >> +	ret = clk_get_bulk(dev, &priv->clks);
> >> +	if (ret) {
> >> +		dev_err(dev, "Can't get clock: %d\n", ret);
> >> +		return ret;
> >> +	}
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int starfive_pcie_init_port(struct udevice *dev)
> >> +{
> >> +	int ret, i;
> >> +	unsigned int value;
> >> +	struct starfive_pcie *priv = dev_get_priv(dev);
> >> +
> >> +	ret = clk_enable_bulk(&priv->clks);
> >> +	if (ret) {
> >> +		dev_err(dev, "Failed to enable clks (ret=%d)\n", ret);
> >> +		return ret;
> >> +	}
> >> +
> >> +	ret = reset_deassert_bulk(&priv->rsts);
> >> +	if (ret) {
> >> +		dev_err(dev, "Failed to deassert resets (ret=%d)\n", ret);
> >> +		goto err_deassert_clk;
> >> +	}
> >> +
> >> +	ret = pinctrl_select_state(dev, "perst-active");
> >> +	if (ret) {
> >> +		dev_err(dev, "Set perst-active pinctrl failed: %d\n", ret);
> >> +		goto err_deassert_reset;
> >> +	}
> >> +
> >> +	/* Disable physical functions except #0 */
> >> +	for (i = 1; i < PLDA_FUNC_NUM; i++) {
> >> +		regmap_update_bits(priv->regmap,
> >> +				   priv->stg_arfun,
> >> +				   STG_SYSCON_AXI4_SLVL_ARFUNC_MASK,
> >> +				   (i << PLDA_PHY_FUNC_SHIFT) <<
> >> +				   STG_SYSCON_AXI4_SLVL_ARFUNC_SHIFT);
> >> +		regmap_update_bits(priv->regmap,
> >> +				   priv->stg_awfun,
> >> +				   STG_SYSCON_AXI4_SLVL_AWFUNC_MASK,
> >> +				   i << PLDA_PHY_FUNC_SHIFT);
> >> +
> >> +		value = readl(priv->reg_base + PCI_MISC);
> >> +		value |= PLDA_FUNCTION_DIS;
> >> +		writel(value, priv->reg_base + PCI_MISC);
> >> +	}
> >> +
> >> +	/* Disable physical functions */
> >> +	regmap_update_bits(priv->regmap,
> >> +			   priv->stg_arfun,
> >> +			   STG_SYSCON_AXI4_SLVL_ARFUNC_MASK,
> >> +			   0);
> >> +	regmap_update_bits(priv->regmap,
> >> +			   priv->stg_awfun,
> >> +			   STG_SYSCON_AXI4_SLVL_AWFUNC_MASK,
> >> +			   0);
> >> +
> >> +	/* Enable root port */
> >> +	value = readl(priv->reg_base + GEN_SETTINGS);
> >> +	value |= PLDA_RP_ENABLE;
> >> +	writel(value, priv->reg_base + GEN_SETTINGS);
> >> +
> >> +	/* PCIe PCI Standard Configuration Identification Settings. */
> >> +	value = (IDS_PCI_TO_PCI_BRIDGE << IDS_CLASS_CODE_SHIFT) | IDS_REVISION_ID;
> >> +	writel(value, priv->reg_base + PCIE_PCI_IDS);
> >> +
> >> +	/* The LTR message forwarding of PCIe Message Reception was set by core
> >> +	 * 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 this driver probe.
> >> +	 * To workaround, disable the LTR message forwarding support on
> >> +	 * PCIe Message Reception.
> >> +	 */
> >> +	value = readl(priv->reg_base + PMSG_SUPPORT_RX);
> >> +	value &= ~PMSG_LTR_SUPPORT;
> >> +	writel(value, priv->reg_base + PMSG_SUPPORT_RX);
> >> +
> >> +	/* Prefetchable memory window 64-bit addressing support */
> >> +	value = readl(priv->reg_base + PCIE_WINROM);
> >> +	value |= PREF_MEM_WIN_64_SUPPORT;
> >> +	writel(value, priv->reg_base + PCIE_WINROM);
> >> +
> >> +	starfive_pcie_atr_init(priv);
> >> +
> >> +	/* Ensure that PERST has been asserted for at least 300 ms */
> >> +	mdelay(300);
> >> +	ret = pinctrl_select_state(dev, "perst-default");
> >> +	if (ret) {
> >> +		dev_err(dev, "Set perst-default pinctrl failed: %d\n", ret);
> >> +		return ret;
> >> +	}
> >> +
> >> +	return 0;
> >> +
> >> +err_deassert_clk:
> >> +	clk_disable_bulk(&priv->clks);
> >> +err_deassert_reset:
> >> +	reset_assert_bulk(&priv->rsts);
> >> +	return ret;
> >> +}
> >> +
> >> +static int starfive_pcie_probe(struct udevice *dev)
> >> +{
> >> +	struct starfive_pcie *priv = dev_get_priv(dev);
> >> +	int ret;
> >> +
> >> +	priv->atr_table_num = 0;
> >> +	priv->dev = dev;
> >> +	priv->first_busno = dev_seq(dev);
> >> +
> >> +	ret = starfive_pcie_parse_dt(dev);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	regmap_update_bits(priv->regmap,
> >> +			   priv->stg_rp_nep,
> >> +			   STG_SYSCON_K_RP_NEP_MASK,
> >> +			   STG_SYSCON_K_RP_NEP_MASK);
> >> +
> >> +	regmap_update_bits(priv->regmap,
> >> +			   priv->stg_awfun,
> >> +			   STG_SYSCON_CKREF_SRC_MASK,
> >> +			   2 << STG_SYSCON_CKREF_SRC_SHIFT);
> >> +
> >> +	regmap_update_bits(priv->regmap,
> >> +			   priv->stg_awfun,
> >> +			   STG_SYSCON_CLKREQ_MASK,
> >> +			   STG_SYSCON_CLKREQ_MASK);
> >> +
> >> +	ret = starfive_pcie_init_port(dev);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	dev_err(dev, "Starfive PCIe bus probed.\n");
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static const struct dm_pci_ops starfive_pcie_ops = {
> >> +	.read_config	= starfive_pcie_config_read,
> >> +	.write_config	= starfive_pcie_config_write,
> >> +};
> >> +
> >> +static const struct udevice_id starfive_pcie_ids[] = {
> >> +	{ .compatible = "starfive,jh7110-pcie" },
> >> +	{ }
> >> +};
> >> +
> >> +U_BOOT_DRIVER(starfive_pcie_drv) = {
> >> +	.name			= "starfive_7110_pcie",
> >> +	.id			= UCLASS_PCI,
> >> +	.of_match		= starfive_pcie_ids,
> >> +	.ops			= &starfive_pcie_ops,
> >> +	.probe			= starfive_pcie_probe,
> >> +	.priv_auto	= sizeof(struct starfive_pcie),
> >> +};
> >> -- 
> >> 2.17.1
> >> 


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