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Message-ID: <20250912230236.GA1650055@bhelgaas>
Date: Fri, 12 Sep 2025 18:02:36 -0500
From: Bjorn Helgaas <helgaas@...nel.org>
To: Vincent Guittot <vincent.guittot@...aro.org>
Cc: chester62515@...il.com, mbrugger@...e.com,
ghennadi.procopciuc@....nxp.com, s32@....com, lpieralisi@...nel.org,
kwilczynski@...nel.org, mani@...nel.org, robh@...nel.org,
krzk+dt@...nel.org, conor+dt@...nel.org, Ionut.Vicovan@....com,
larisa.grigore@....com, Ghennadi.Procopciuc@....com,
ciprianmarian.costea@....com, bogdan.hamciuc@....com,
linux-arm-kernel@...ts.infradead.org, linux-pci@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4] pcie: s32g: Add initial PCIe support (RC)
Run "git log --oneline drivers/pci/controller/dwc" and follow the
subject line convention.
On Fri, Sep 12, 2025 at 04:14:35PM +0200, Vincent Guittot wrote:
> Add initial support of the PCIe controller for S32G Soc family. Only
> host mode is supported.
> +++ b/drivers/pci/controller/dwc/Kconfig
> @@ -255,6 +255,18 @@ config PCIE_TEGRA194_EP
> in order to enable device-specific features PCIE_TEGRA194_EP must be
> selected. This uses the DesignWare core.
>
> +config PCI_S32G
> + bool "NXP S32G PCIe controller (host mode)"
> + depends on ARCH_S32 || (OF && COMPILE_TEST)
> + select PCIE_DW_HOST
> + help
> + Enable support for the PCIe controller in NXP S32G based boards to
> + work in Host mode. The controller is based on Designware IP and
> + can work either as RC or EP. In order to enable host-specific
> + features PCI_S32G must be selected and in order to enable
> + device-specific features PCI_S32G_EP must be selected.
s/Designware/DesignWare/
"enable host-specific features" is oddly specific. You need PCI_S32G
to make S32G PCIe work at all.
Remove PCI_S32G_EP since you didn't add that. There are several
references to endpoint mode in the code below; you should probably
remove those as well until you add that support.
> +++ b/drivers/pci/controller/dwc/pci-s32g-regs.h
Squash this into pcie-s32g.c. No need to add a separate include file.
Maybe if/when you add endpoint support, but no need now.
> +/* Instance PCIE_SS - CTRL register offsets (ctrl base) */
> +#define LINK_INT_CTRL_STS (0x40U)
Unnecessary parens. Unnecessary "U".
> +#define LINK_REQ_RST_NOT_INT_EN BIT(1)
> +#define LINK_REQ_RST_NOT_CLR BIT(2)
> +
> +/* PCIe controller 0 general control 1 (PE0_GEN_CTRL_1) (ctrl base) */
> +#define PE0_GEN_CTRL_1 (0x50U)
> +#define SS_DEVICE_TYPE_MASK GENMASK(3, 0)
> +#define SS_DEVICE_TYPE(x) FIELD_PREP(SS_DEVICE_TYPE_MASK, x)
> +
> +enum pcie_dev_type_val {
> + PCIE_EP_VAL = 0x0,
> + PCIE_RC_VAL = 0x4
> +};
Use the existing PCI_EXP_TYPE_ENDPOINT, PCI_EXP_TYPE_ROOT_PORT.
> +
> +#define SRIS_MODE_EN BIT(8)
> +
> +/* PCIe controller 0 general control 3 (PE0_GEN_CTRL_3) (ctrl base) */
> +#define PE0_GEN_CTRL_3 (0x58U)
> +/* LTSSM Enable. Active high. Set it low to hold the LTSSM in Detect state. */
> +#define LTSSM_EN BIT(0)
> +
> +/* PCIe Controller 0 Link Debug 2 (ctrl base) */
> +#define PCIE_SS_PE0_LINK_DBG_2 (0xB4U)
> +#define PCIE_SS_SMLH_LTSSM_STATE_MASK GENMASK(5, 0)
> +#define PCIE_SS_SMLH_LINK_UP BIT(6)
> +#define PCIE_SS_RDLH_LINK_UP BIT(7)
> +#define LTSSM_STATE_L0 0x11U /* L0 state */
> +#define LTSSM_STATE_L0S 0x12U /* L0S state */
> +#define LTSSM_STATE_L1_IDLE 0x14U /* L1_IDLE state */
> +#define LTSSM_STATE_HOT_RESET 0x1FU /* HOT_RESET state */
> +
> +/* PCIe Controller 0 Interrupt Status (ctrl base) */
> +#define PE0_INT_STS (0xE8U)
> +#define HP_INT_STS BIT(6)
> +
> +/* Status and Command Register. pci-regs.h */
> +
> +/* Instance PCIE_CAP */
> +#define PCIE_CAP_BASE (0x70U)
Should be able to use dw_pcie_find_capability() or similar to avoid
hard-coding this.
> +/* Device Control and Status Register. */
> +#define CAP_DEVICE_CONTROL_DEVICE_STATUS (PCIE_CAP_BASE + PCI_EXP_DEVCTL)
Use PCI_EXP_DEVCTL and PCI_EXP_DEVSTA directly in the code so grep
finds the uses easily. Same for link, slot, etc. below.
> +#define CAP_CORR_ERR_REPORT_EN BIT(0)
> +#define CAP_NON_FATAL_ERR_REPORT_EN BIT(1)
> +#define CAP_FATAL_ERR_REPORT_EN BIT(2)
> +#define CAP_UNSUPPORT_REQ_REP_EN BIT(3)
> +#define CAP_EN_REL_ORDER BIT(4)
> +#define CAP_MAX_PAYLOAD_SIZE_CS_MASK GENMASK(7, 5)
> +#define CAP_MAX_PAYLOAD_SIZE_CS(x) FIELD_PREP(CAP_MAX_PAYLOAD_SIZE_CS_MASK, x)
> +#define CAP_MAX_READ_REQ_SIZE_MASK GENMASK(14, 12)
> +#define CAP_MAX_READ_REQ_SIZE(x) FIELD_PREP(CAP_MAX_READ_REQ_SIZE_MASK, x)
Use existing PCI_EXP_DEVCTL_CERE, PCI_EXP_DEVCTL_NFERE, etc. so grep
finds these easily.
> +/* Link Control and Status Register. */
> +#define PCIE_CTRL_LINK_STATUS (PCIE_CAP_BASE + PCI_EXP_LNKCTL)
> +#define PCIE_CAP_RETRAIN_LINK BIT(5)
> +#define PCIE_CAP_LINK_TRAINING BIT(27)
> +
> +/* Slot Control and Status Register */
> +#define PCIE_SLOT_CONTROL_SLOT_STATUS (PCIE_CAP_BASE + PCI_EXP_SLTCTL)
> +#define PCIE_CAP_PRESENCE_DETECT_CHANGE_EN BIT(3)
> +#define PCIE_CAP_HOT_PLUG_INT_EN BIT(5)
> +#define PCIE_CAP_DLL_STATE_CHANGED_EN BIT(12)
> +
> +/* Link Control 2 and Status 2 Register. */
> +#define CAP_LINK_CONTROL2_LINK_STATUS2 (PCIE_CAP_BASE + PCI_EXP_LNKCTL2)
> +#define PCIE_CAP_TARGET_LINK_SPEED_MASK GENMASK(3, 0)
> +#define PCIE_CAP_TARGET_LINK_SPEED(x) FIELD_PREP(PCIE_CAP_TARGET_LINK_SPEED_MASK, x)
> +
> +/* Instance PCIE_PORT_LOGIC - DBI register offsets */
> +#define PCIE_PORT_LOGIC_BASE (0x700U)
> +
> +/* Port Force Link Register. pcie-designware.h */
> +
> +/* Link Width and Speed Change Control Register. pcie-designware.h */
> +
> +/* Gen3 Control Register. pcie-designware.h */
> +#define PCIE_EQ_PHASE_2_3 BIT(9)
> +
> +/* Gen3 EQ Control Register. pcie-designware.h */
> +
> +/* ACE Cache Coherency Control Register 3 */
> +#define PORT_LOGIC_COHERENCY_CONTROL_1 (PCIE_PORT_LOGIC_BASE + 0x1E0U)
> +#define PORT_LOGIC_COHERENCY_CONTROL_2 (PCIE_PORT_LOGIC_BASE + 0x1E4U)
> +#define PORT_LOGIC_COHERENCY_CONTROL_3 (PCIE_PORT_LOGIC_BASE + 0x1E8U)
Add blank line before comment.
> +/*
> + * See definition of register "ACE Cache Coherency Control Register 1"
> + * (COHERENCY_CONTROL_1_OFF) in the SoC RM
> + */
> +#define CC_1_MEMTYPE_BOUNDARY_MASK GENMASK(31, 2)
> +#define CC_1_MEMTYPE_BOUNDARY(x) FIELD_PREP(CC_1_MEMTYPE_BOUNDARY_MASK, x)
> +#define CC_1_MEMTYPE_VALUE BIT(0)
> +#define CC_1_MEMTYPE_LOWER_PERIPH 0x0
> +#define CC_1_MEMTYPE_LOWER_MEM 0x1
> +
> +#endif /* PCI_S32G_REGS_H */
> diff --git a/drivers/pci/controller/dwc/pci-s32g.c b/drivers/pci/controller/dwc/pci-s32g.c
> new file mode 100644
> index 000000000000..3a7c2fc83432
> --- /dev/null
> +++ b/drivers/pci/controller/dwc/pci-s32g.c
> @@ -0,0 +1,697 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * PCIe host controller driver for NXP S32G SoCs
> + *
> + * Copyright 2019-2025 NXP
> + */
> +
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/of_device.h>
> +#include <linux/of_address.h>
> +#include <linux/pci.h>
> +#include <linux/phy.h>
> +#include <linux/phy/phy.h>
> +#include <linux/interrupt.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/io.h>
> +#include <linux/sizes.h>
Alphabetize the includes above.
> +#include "pcie-designware.h"
> +#include "pci-s32g-regs.h"
> +#include "pci-s32g.h"
> +
> +static void s32g_pcie_writel_ctrl(struct s32g_pcie *pci, u32 reg, u32 val)
> +{
> + if (dw_pcie_write(pci->ctrl_base + reg, 0x4, val))
> + dev_err(pci->pcie.dev, "Write ctrl address failed\n");
> +}
> +
> +static u32 s32g_pcie_readl_ctrl(struct s32g_pcie *pci, u32 reg)
> +{
> + u32 val = 0;
> +
> + if (dw_pcie_read(pci->ctrl_base + reg, 0x4, &val))
> + dev_err(pci->pcie.dev, "Read ctrl address failed\n");
> +
> + return val;
> +}
> +
> +static void s32g_pcie_enable_ltssm(struct s32g_pcie *pci)
> +{
> + u32 reg;
> +
> + reg = s32g_pcie_readl_ctrl(pci, PE0_GEN_CTRL_3);
> + reg |= LTSSM_EN;
> + s32g_pcie_writel_ctrl(pci, PE0_GEN_CTRL_3, reg);
> +}
> +
> +static void s32g_pcie_disable_ltssm(struct s32g_pcie *pci)
> +{
> + u32 reg;
> +
> + reg = s32g_pcie_readl_ctrl(pci, PE0_GEN_CTRL_3);
> + reg &= ~LTSSM_EN;
> + s32g_pcie_writel_ctrl(pci, PE0_GEN_CTRL_3, reg);
> +}
> +
> +static bool is_s32g_pcie_ltssm_enabled(struct s32g_pcie *pci)
> +{
> + return (s32g_pcie_readl_ctrl(pci, PE0_GEN_CTRL_3) & LTSSM_EN);
> +}
> +
> +#define PCIE_LINKUP (PCIE_SS_SMLH_LINK_UP | PCIE_SS_RDLH_LINK_UP)
> +
> +static bool has_data_phy_link(struct s32g_pcie *s32g_pp)
> +{
> + u32 val = s32g_pcie_readl_ctrl(s32g_pp, PCIE_SS_PE0_LINK_DBG_2);
> +
> + if ((val & PCIE_LINKUP) == PCIE_LINKUP) {
> + switch (val & PCIE_SS_SMLH_LTSSM_STATE_MASK) {
> + case LTSSM_STATE_L0:
> + case LTSSM_STATE_L0S:
> + case LTSSM_STATE_L1_IDLE:
> + return true;
> + default:
> + return false;
> + }
> + }
> +
> + return false;
> +}
> +
> +static struct pci_bus *s32g_get_child_downstream_bus(struct pci_bus *bus)
> +{
> + struct pci_bus *child, *root_bus = NULL;
> +
> + list_for_each_entry(child, &bus->children, node) {
> + if (child->parent == bus) {
> + root_bus = child;
> + break;
> + }
> + }
> +
> + if (!root_bus)
> + return ERR_PTR(-ENODEV);
> +
> + return root_bus;
> +}
> +
> +static bool s32g_pcie_link_is_up(struct dw_pcie *pcie)
Use names similar to other drivers, "s32g_pcie_link_up" in this case.
> +{
> + struct s32g_pcie *s32g_pp = to_s32g_from_dw_pcie(pcie);
> +
> + if (!is_s32g_pcie_ltssm_enabled(s32g_pp))
> + return 0;
> +
> + return has_data_phy_link(s32g_pp);
> +}
> +
> +/* Use 200ms for PHY link timeout (slightly larger than 100ms, which PCIe standard requests
> + * to wait "before sending a Configuration Request to the device")
Use same comment style as other drivers, e.g.,
/*
* Use 200ms ...
*/
> + */
> +#define PCIE_LINK_TIMEOUT_US (200 * USEC_PER_MSEC)
> +#define PCIE_LINK_WAIT_US 1000
Instead of defining your own, use #defines from drivers/pci/pci.h for
values from the PCIe spec.
> +static int s32g_pcie_start_link(struct dw_pcie *pcie)
> +{
> + struct s32g_pcie *s32g_pp = to_s32g_from_dw_pcie(pcie);
> + u32 reg, tmp;
> + int ret;
> +
> + /* Don't do anything if not Root Complex */
> + if (!is_s32g_pcie_rc(s32g_pp->mode))
> + return 0;
> +
> + if (pcie->max_link_speed >= 1 && pcie->max_link_speed < 3) {
> + /* Limit max link speed */
> + reg = dw_pcie_readl_dbi(pcie, CAP_LINK_CONTROL2_LINK_STATUS2);
> + reg &= ~(PCIE_CAP_TARGET_LINK_SPEED_MASK);
> + reg |= PCIE_CAP_TARGET_LINK_SPEED(pcie->max_link_speed);
> + dw_pcie_writel_dbi(pcie, CAP_LINK_CONTROL2_LINK_STATUS2, reg);
> +
> + if (is_s32g_pcie_ltssm_enabled(s32g_pp)) {
> + ret = read_poll_timeout(dw_pcie_readl_dbi, tmp,
> + !(tmp & PCIE_CAP_LINK_TRAINING),
> + PCIE_LINK_WAIT_US, PCIE_LINK_TIMEOUT_US, 0,
> + pcie, PCIE_CTRL_LINK_STATUS);
> + if (ret)
> + dev_warn(s32g_pp->pcie.dev,
> + "Failed to finalize link training\n");
> +
> + reg = dw_pcie_readl_dbi(pcie, PCIE_CTRL_LINK_STATUS);
> + reg |= PCIE_CAP_RETRAIN_LINK;
> + dw_pcie_writel_dbi(pcie, PCIE_CTRL_LINK_STATUS, reg);
> + }
> + }
> +
> + /* Start LTSSM. */
> + s32g_pcie_enable_ltssm(s32g_pp);
> +
> + return 0;
> +}
> +
> +static void s32g_pcie_stop_link(struct dw_pcie *pcie)
> +{
> + struct s32g_pcie *s32g_pp = to_s32g_from_dw_pcie(pcie);
> +
> + s32g_pcie_disable_ltssm(s32g_pp);
> +}
> +
> +struct dw_pcie_ops s32g_pcie_ops = {
> + .link_up = s32g_pcie_link_is_up,
> + .start_link = s32g_pcie_start_link,
> + .stop_link = s32g_pcie_stop_link,
> +};
> +
> +static struct dw_pcie_host_ops s32g_pcie_host_ops;
Probably should be const. I guess you don't need anything filled in?
That would be unusual, but there are a couple drivers like that
(amd_mdb_pcie_host_ops, dw_plat_pcie_host_ops, keembay_pcie_host_ops).
> +static void s32g_pcie_set_phy_mode(struct s32g_pcie *s32g_pp)
> +{
> + struct dw_pcie *pcie = &s32g_pp->pcie;
> + struct device *dev = pcie->dev;
> + struct device_node *np = dev->of_node;
> + const char *pcie_phy_mode = NULL;
> + int ret;
> +
> + ret = of_property_read_string(np, "nxp,phy-mode", &pcie_phy_mode);
> + if (ret || !pcie_phy_mode) {
> + dev_info(dev, "Missing 'nxp,phy-mode' property, using default CRNS\n");
> + s32g_pp->phy_mode = CRNS;
> + } else if (!strcmp(pcie_phy_mode, "crns")) {
> + s32g_pp->phy_mode = CRNS;
> + } else if (!strcmp(pcie_phy_mode, "crss")) {
> + s32g_pp->phy_mode = CRSS;
> + } else if (!strcmp(pcie_phy_mode, "srns")) {
> + s32g_pp->phy_mode = SRNS;
> + } else if (!strcmp(pcie_phy_mode, "sris")) {
> + s32g_pp->phy_mode = SRIS;
> + } else {
> + dev_warn(dev, "Unsupported 'nxp,phy-mode' specified, using default CRNS\n");
> + s32g_pp->phy_mode = CRNS;
> + }
> +}
> +
> +static void disable_equalization(struct dw_pcie *pcie)
> +{
> + u32 val;
> +
> + val = dw_pcie_readl_dbi(pcie, GEN3_EQ_CONTROL_OFF);
> + val &= ~(GEN3_EQ_CONTROL_OFF_FB_MODE |
> + GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC);
> + val |= FIELD_PREP(GEN3_EQ_CONTROL_OFF_FB_MODE, 1) |
> + FIELD_PREP(GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC, 0x84);
> + dw_pcie_dbi_ro_wr_en(pcie);
> + dw_pcie_writel_dbi(pcie, GEN3_EQ_CONTROL_OFF, val);
> + dw_pcie_dbi_ro_wr_dis(pcie);
> +}
> +
> +static void s32g_pcie_reset_mstr_ace(struct dw_pcie *pcie, u64 ddr_base_addr)
> +{
> + u32 ddr_base_low = lower_32_bits(ddr_base_addr);
> + u32 ddr_base_high = upper_32_bits(ddr_base_addr);
> +
> + dw_pcie_dbi_ro_wr_en(pcie);
> + dw_pcie_writel_dbi(pcie, PORT_LOGIC_COHERENCY_CONTROL_3, 0x0);
Add blank line here before comment and use conventional comment style
(first line is "/*" only).
> + /* Transactions to peripheral targets should be non-coherent,
> + * or Ncore might drop them. Define the start of DDR as seen by Linux
> + * as the boundary between "memory" and "peripherals", with peripherals
> + * being below this boundary, and memory addresses being above it.
> + * One example where this is needed are PCIe MSIs, which use NoSnoop=0
> + * and might end up routed to Ncore.
> + */
> + dw_pcie_writel_dbi(pcie, PORT_LOGIC_COHERENCY_CONTROL_1,
> + (ddr_base_low & CC_1_MEMTYPE_BOUNDARY_MASK) |
> + (CC_1_MEMTYPE_LOWER_PERIPH & CC_1_MEMTYPE_VALUE));
> + dw_pcie_writel_dbi(pcie, PORT_LOGIC_COHERENCY_CONTROL_2, ddr_base_high);
> + dw_pcie_dbi_ro_wr_dis(pcie);
> +}
> +
> +static int init_pcie(struct s32g_pcie *s32g_pp)
> +{
> + struct dw_pcie *pcie = &s32g_pp->pcie;
> + u32 val;
> +
> + val = s32g_pcie_readl_ctrl(s32g_pp, PE0_GEN_CTRL_1);
> + val &= ~SS_DEVICE_TYPE_MASK;
> +
> + if (is_s32g_pcie_rc(s32g_pp->mode))
> + val |= SS_DEVICE_TYPE(PCIE_RC_VAL);
> + else
> + val |= SS_DEVICE_TYPE(PCIE_EP_VAL);
> +
> + if (s32g_pp->phy_mode == SRIS)
> + val |= SRIS_MODE_EN;
> + else
> + val &= ~SRIS_MODE_EN;
> +
> + s32g_pcie_writel_ctrl(s32g_pp, PE0_GEN_CTRL_1, val);
> +
> + /* Disable phase 2,3 equalization */
> + disable_equalization(pcie);
> +
> + /* Make sure DBI registers are R/W - see dw_pcie_setup_rc */
> + dw_pcie_dbi_ro_wr_en(pcie);
> + dw_pcie_setup(pcie);
> + dw_pcie_dbi_ro_wr_dis(pcie);
> +
> + /* Make sure we use the coherency defaults (just in case the settings
> + * have been changed from their reset values
> + */
> + s32g_pcie_reset_mstr_ace(pcie, s32g_pp->coherency_base);
> +
> + val = dw_pcie_readl_dbi(pcie, PCIE_PORT_FORCE);
> + val |= PORT_FORCE_DO_DESKEW_FOR_SRIS;
> + dw_pcie_dbi_ro_wr_en(pcie);
> + dw_pcie_writel_dbi(pcie, PCIE_PORT_FORCE, val);
> +
> + if (is_s32g_pcie_rc(s32g_pp->mode)) {
> + /* Set max payload supported, 256 bytes and
> + * relaxed ordering.
> + */
> + val = dw_pcie_readl_dbi(pcie, CAP_DEVICE_CONTROL_DEVICE_STATUS);
> + val &= ~(CAP_EN_REL_ORDER |
> + CAP_MAX_PAYLOAD_SIZE_CS_MASK |
> + CAP_MAX_READ_REQ_SIZE_MASK);
> + val |= CAP_EN_REL_ORDER |
> + CAP_MAX_PAYLOAD_SIZE_CS(1) |
> + CAP_MAX_READ_REQ_SIZE(1);
> + dw_pcie_writel_dbi(pcie, CAP_DEVICE_CONTROL_DEVICE_STATUS, val);
> +
> + /* Enable the IO space, Memory space, Bus master,
> + * Parity error, Serr and disable INTx generation
> + */
> + dw_pcie_writel_dbi(pcie, PCI_COMMAND,
> + PCI_COMMAND_SERR | PCI_COMMAND_PARITY |
> + PCI_COMMAND_INTX_DISABLE | PCI_COMMAND_IO |
> + PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER);
> +
> + /* Enable errors */
> + val = dw_pcie_readl_dbi(pcie, CAP_DEVICE_CONTROL_DEVICE_STATUS);
> + val |= CAP_CORR_ERR_REPORT_EN |
> + CAP_NON_FATAL_ERR_REPORT_EN |
> + CAP_FATAL_ERR_REPORT_EN |
> + CAP_UNSUPPORT_REQ_REP_EN;
> + dw_pcie_writel_dbi(pcie, CAP_DEVICE_CONTROL_DEVICE_STATUS, val);
> + }
> +
> + val = dw_pcie_readl_dbi(pcie, GEN3_RELATED_OFF);
> + val |= PCIE_EQ_PHASE_2_3;
> + dw_pcie_writel_dbi(pcie, GEN3_RELATED_OFF, val);
> +
> + /* Disable writing dbi registers */
> + dw_pcie_dbi_ro_wr_dis(pcie);
> +
> + s32g_pcie_enable_ltssm(s32g_pp);
> +
> + return 0;
> +}
> +
> +static int init_pcie_phy(struct s32g_pcie *s32g_pp)
> +{
> + struct dw_pcie *pcie = &s32g_pp->pcie;
> + struct device *dev = pcie->dev;
> + int ret;
> +
> + ret = phy_init(s32g_pp->phy);
> + if (ret) {
> + dev_err(dev, "Failed to init serdes PHY\n");
> + return ret;
> + }
> +
> + ret = phy_set_mode_ext(s32g_pp->phy, PHY_MODE_PCIE,
> + s32g_pp->phy_mode);
> + if (ret) {
> + dev_err(dev, "Failed to set mode on serdes PHY\n");
> + goto err_phy_exit;
> + }
> +
> + ret = phy_power_on(s32g_pp->phy);
> + if (ret) {
> + dev_err(dev, "Failed to power on serdes PHY\n");
> + goto err_phy_exit;
> + }
> +
> + return 0;
> +
> +err_phy_exit:
> + phy_exit(s32g_pp->phy);
> + return ret;
> +}
> +
> +static int deinit_pcie_phy(struct s32g_pcie *s32g_pp)
> +{
> + struct dw_pcie *pcie = &s32g_pp->pcie;
> + struct device *dev = pcie->dev;
> + int ret;
> +
> + if (s32g_pp->phy) {
> + ret = phy_power_off(s32g_pp->phy);
> + if (ret) {
> + dev_err(dev, "Failed to power off serdes PHY\n");
> + return ret;
> + }
> +
> + ret = phy_exit(s32g_pp->phy);
> + if (ret) {
> + dev_err(dev, "Failed to exit serdes PHY\n");
> + return ret;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static int wait_phy_data_link(struct s32g_pcie *s32g_pp)
> +{
> + bool has_link;
> + int ret;
> +
> + ret = read_poll_timeout(has_data_phy_link, has_link, has_link,
> + PCIE_LINK_WAIT_US, PCIE_LINK_TIMEOUT_US, 0, s32g_pp);
> + if (ret)
> + dev_info(s32g_pp->pcie.dev, "Failed to stabilize PHY link\n");
> +
> + return ret;
> +}
> +
> +static void s32g_pcie_downstream_dev_to_D0(struct s32g_pcie *s32g_pp)
> +{
> + struct dw_pcie *pcie = &s32g_pp->pcie;
> + struct dw_pcie_rp *pp = &pcie->pp;
> + struct pci_bus *root_bus = NULL;
> + struct pci_dev *pdev;
> +
> + /* Check if we did manage to initialize the host */
> + if (!pp->bridge || !pp->bridge->bus)
> + return;
> +
> + /*
> + * link doesn't go into L2 state with some of the EndPoints
> + * if they are not in D0 state. So, we need to make sure that immediate
> + * downstream devices are in D0 state before sending PME_TurnOff to put
> + * link into L2 state.
s/EndPoint/Endpoint/ to match PCIe spec usage. More cases below.
Wrap comments to fill 78 columns.
I'm doubtful about the need for this function since most drivers don't
do this.
> + */
> +
> + root_bus = s32g_get_child_downstream_bus(pp->bridge->bus);
> + if (IS_ERR(root_bus)) {
> + dev_err(pcie->dev, "Failed to find downstream devices\n");
> + return;
> + }
> +
> + list_for_each_entry(pdev, &root_bus->devices, bus_list) {
> + if (PCI_SLOT(pdev->devfn) == 0) {
> + if (pci_set_power_state(pdev, PCI_D0))
> + dev_err(pcie->dev,
> + "Failed to transition %s to D0 state\n",
> + dev_name(&pdev->dev));
> + }
> + }
> +}
> +
> +static u64 s32g_get_coherency_boundary(struct device *dev)
> +{
> + struct device_node *np;
> + struct resource res;
> +
> + np = of_find_node_by_type(NULL, "memory");
> +
> + if (of_address_to_resource(np, 0, &res)) {
> + dev_warn(dev, "Fail to get coherency boundary\n");
> + return 0;
> + }
> +
> + return res.start;
> +}
> +
> +static int s32g_pcie_init_common(struct platform_device *pdev,
> + struct s32g_pcie *s32g_pp,
> + const struct s32g_pcie_data *data)
> +{
> + struct device *dev = &pdev->dev;
> + struct dw_pcie *pcie = &s32g_pp->pcie;
> + struct phy *phy;
> +
> + pcie->dev = dev;
> + pcie->ops = &s32g_pcie_ops;
> +
> + s32g_pp->mode = data->mode;
> +
> + platform_set_drvdata(pdev, s32g_pp);
> +
> + phy = devm_phy_get(dev, NULL);
> + if (IS_ERR(phy))
> + return dev_err_probe(dev, PTR_ERR(phy),
> + "Failed to get serdes PHY\n");
> + s32g_pp->phy = phy;
> +
> + s32g_pcie_set_phy_mode(s32g_pp);
> +
> + pcie->dbi_base = devm_platform_ioremap_resource_byname(pdev, "dbi");
> + if (IS_ERR(pcie->dbi_base))
> + return PTR_ERR(pcie->dbi_base);
> +
> + pcie->dbi_base2 = devm_platform_ioremap_resource_byname(pdev, "dbi2");
> + if (IS_ERR(pcie->dbi_base2))
> + return PTR_ERR(pcie->dbi_base2);
> +
> + pcie->atu_base = devm_platform_ioremap_resource_byname(pdev, "atu");
> + if (IS_ERR(pcie->atu_base))
> + return PTR_ERR(pcie->atu_base);
> +
> + s32g_pp->ctrl_base = devm_platform_ioremap_resource_byname(pdev, "ctrl");
> + if (IS_ERR(s32g_pp->ctrl_base))
> + return PTR_ERR(s32g_pp->ctrl_base);
> +
> + s32g_pp->coherency_base = s32g_get_coherency_boundary(dev);
> +
> + return 0;
> +}
> +
> +static int s32g_pcie_init_host(struct platform_device *pdev,
> + struct s32g_pcie *s32g_pp)
> +{
> + struct dw_pcie *pcie = &s32g_pp->pcie;
> + struct dw_pcie_rp *pp = &pcie->pp;
> +
> + /* Set dw host ops */
> + pp->ops = &s32g_pcie_host_ops;
Seems overkill to make this a separate function. Most do it in
*_add_pcie_port() or *_pcie_probe():
git grep -p "pp->ops =" drivers/pci/controller/
Follow the structure and function names of other drivers whenever
possible.
> + return 0;
> +}
> +
> +static int s32g_pcie_config_common(struct device *dev,
> + struct s32g_pcie *s32g_pp)
> +{
> + int ret = 0;
Unnecessary init.
> + s32g_pcie_disable_ltssm(s32g_pp);
> +
> + ret = init_pcie_phy(s32g_pp);
> + if (ret)
> + return ret;
> +
> + ret = init_pcie(s32g_pp);
> + if (ret)
> + goto err_deinit_phy;
> +
> + return 0;
> +
> +err_deinit_phy:
> + deinit_pcie_phy(s32g_pp);
> + return ret;
> +}
> +
> +static void s32g_pcie_deconfig_common(struct s32g_pcie *s32g_pp)
> +{
> + s32g_pcie_disable_ltssm(s32g_pp);
> + deinit_pcie_phy(s32g_pp);
> +}
> +
> +static int s32g_pcie_config_host(struct device *dev,
> + struct s32g_pcie *s32g_pp)
> +{
> + struct dw_pcie *pcie = &s32g_pp->pcie;
Typical struct dw_pcie * variable name is "pci".
> + struct dw_pcie_rp *pp = &pcie->pp;
> + int ret = 0;
Pointless init.
> + ret = wait_phy_data_link(s32g_pp);
> + if ((ret) && (!phy_validate(s32g_pp->phy, PHY_MODE_PCIE, 0, NULL))) {
> + dev_err(pcie->dev, "Failed to get link up with EP connected\n");
> + goto err_host_deinit;
> + }
> +
> + ret = dw_pcie_host_init(pp);
> + if (ret) {
> + dev_err(dev, "Failed to initialize host\n");
> + goto err_host_deinit;
> + }
> +
> + return 0;
> +
> +err_host_deinit:
> + dw_pcie_host_deinit(pp);
> + return ret;
> +}
> +
> +static int s32g_pcie_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct s32g_pcie *s32g_pp;
Typical driver struct pointers are named "pcie".
> + const struct s32g_pcie_data *data;
> + int ret = 0;
Pointless init.
> + data = of_device_get_match_data(dev);
> + if (!data)
> + return -EINVAL;
> +
> + s32g_pp = devm_kzalloc(dev, sizeof(*s32g_pp), GFP_KERNEL);
> + if (!s32g_pp)
> + return -ENOMEM;
> +
> + ret = s32g_pcie_init_common(pdev, s32g_pp, data);
> + if (ret)
> + return ret;
> +
> + ret = s32g_pcie_init_host(pdev, s32g_pp);
> + if (ret)
> + return ret;
> +
> + pm_runtime_enable(dev);
> + ret = pm_runtime_get_sync(dev);
> + if (ret < 0)
> + goto err_pm_runtime_put;
> +
> + ret = s32g_pcie_config_common(dev, s32g_pp);
> + if (ret)
> + goto err_pm_runtime_put;
> +
> + ret = s32g_pcie_config_host(dev, s32g_pp);
> + if (ret)
> + goto err_deinit_controller;
> +
> + return 0;
> +
> +err_deinit_controller:
> + s32g_pcie_deconfig_common(s32g_pp);
> +err_pm_runtime_put:
> + pm_runtime_put(dev);
> + pm_runtime_disable(dev);
> +
> + return ret;
> +}
> +
> +static void s32g_pcie_shutdown(struct platform_device *pdev)
> +{
> + pm_runtime_put(&pdev->dev);
> + pm_runtime_disable(&pdev->dev);
> +}
> +
> +static int s32g_pcie_suspend(struct device *dev)
> +{
> + struct s32g_pcie *s32g_pp = dev_get_drvdata(dev);
> + struct dw_pcie *pcie = &s32g_pp->pcie;
> + struct dw_pcie_rp *pp = &pcie->pp;
> + struct pci_bus *bus, *root_bus;
> +
> + /* Save MSI interrupt vector */
> + s32g_pp->msi_ctrl_int = dw_pcie_readl_dbi(pcie,
> + PCIE_MSI_INTR0_ENABLE);
> +
> + if (is_s32g_pcie_rc(s32g_pp->mode)) {
> + s32g_pcie_downstream_dev_to_D0(s32g_pp);
> +
> + bus = pp->bridge->bus;
> + root_bus = s32g_get_child_downstream_bus(bus);
> + if (!IS_ERR(root_bus))
> + pci_walk_bus(root_bus, pci_dev_set_disconnected, NULL);
> +
> + pci_stop_root_bus(bus);
> + pci_remove_root_bus(bus);
> + }
> +
> + s32g_pcie_deconfig_common(s32g_pp);
> +
> + return 0;
> +}
> +
> +static int s32g_pcie_resume(struct device *dev)
> +{
> + struct s32g_pcie *s32g_pp = dev_get_drvdata(dev);
> + struct dw_pcie *pcie = &s32g_pp->pcie;
> + struct dw_pcie_rp *pp = &pcie->pp;
> + int ret = 0;
> +
> + ret = s32g_pcie_config_common(dev, s32g_pp);
> + if (ret < 0)
> + return ret;
> +
> + if (is_s32g_pcie_rc(s32g_pp->mode)) {
> + ret = dw_pcie_setup_rc(pp);
> + if (ret) {
> + dev_err(dev, "Failed to resume DW RC: %d\n", ret);
> + goto fail_host_init;
> + }
> +
> + ret = dw_pcie_start_link(pcie);
> + if (ret) {
> + /* We do not exit with error if link up was unsuccessful
> + * EndPoint may not be connected.
> + */
> + if (dw_pcie_wait_for_link(pcie))
> + dev_warn(pcie->dev,
> + "Link Up failed, EndPoint may not be connected\n");
> +
> + if (!phy_validate(s32g_pp->phy, PHY_MODE_PCIE, 0, NULL)) {
> + dev_err(dev, "Failed to get link up with EP connected\n");
> + goto fail_host_init;
> + }
> + }
> +
> + ret = pci_host_probe(pp->bridge);
> + if (ret)
> + goto fail_host_init;
> + }
> +
> + /* Restore MSI interrupt vector */
> + dw_pcie_writel_dbi(pcie, PCIE_MSI_INTR0_ENABLE,
> + s32g_pp->msi_ctrl_int);
> +
> + return 0;
> +
> +fail_host_init:
> + s32g_pcie_deconfig_common(s32g_pp);
> + return ret;
> +}
> +
> +static const struct dev_pm_ops s32g_pcie_pm_ops = {
> + SYSTEM_SLEEP_PM_OPS(s32g_pcie_suspend,
> + s32g_pcie_resume)
> +};
> +
> +static const struct s32g_pcie_data rc_of_data = {
> + .mode = DW_PCIE_RC_TYPE,
> +};
Looks like you don't need this yet, since you only support RC mode.
Don't add data structures or code that isn't exercised yet.
> +static const struct of_device_id s32g_pcie_of_match[] = {
> + { .compatible = "nxp,s32g2-pcie", .data = &rc_of_data },
> + { /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, s32g_pcie_of_match);
> +
> +static struct platform_driver s32g_pcie_driver = {
> + .driver = {
> + .name = "s32g-pcie",
> + .owner = THIS_MODULE,
> + .of_match_table = s32g_pcie_of_match,
> + .pm = pm_sleep_ptr(&s32g_pcie_pm_ops),
> + },
> + .probe = s32g_pcie_probe,
> + .shutdown = s32g_pcie_shutdown,
> +};
> +
> +module_platform_driver(s32g_pcie_driver);
> +
> +MODULE_AUTHOR("Ionut Vicovan <Ionut.Vicovan@....com>");
> +MODULE_DESCRIPTION("NXP S32G PCIe Host controller driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/pci/controller/dwc/pci-s32g.h b/drivers/pci/controller/dwc/pci-s32g.h
> new file mode 100644
> index 000000000000..cdd0c635cc72
> --- /dev/null
> +++ b/drivers/pci/controller/dwc/pci-s32g.h
> @@ -0,0 +1,45 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * PCIe host controller driver for NXP S32G SoCs
> + *
> + * Copyright 2019-2025 NXP
> + */
> +
> +#ifndef PCIE_S32G_H
> +#define PCIE_S32G_H
> +
> +#include <linux/types.h>
> +#include <linux/pcie/nxp-s32g-pcie-phy-submode.h>
> +
> +#define to_s32g_from_dw_pcie(x) \
> + container_of(x, struct s32g_pcie, pcie)
> +
> +struct s32g_pcie_data {
> + enum dw_pcie_device_mode mode;
> +};
> +
> +struct s32g_pcie {
> + struct dw_pcie pcie;
> +
> + u32 msi_ctrl_int;
> +
> + /* we have cfg in struct dw_pcie_rp and
> + * dbi in struct dw_pcie, so define only ctrl here
> + */
> + void __iomem *ctrl_base;
> + u64 coherency_base;
> +
> + enum dw_pcie_device_mode mode;
> +
> + enum pcie_phy_mode phy_mode;
> +
> + struct phy *phy;
> +};
> +
> +static inline
> +bool is_s32g_pcie_rc(enum dw_pcie_device_mode mode)
> +{
> + return mode == DW_PCIE_RC_TYPE;
> +}
> +
> +#endif /* PCIE_S32G_H */
> --
> 2.43.0
>
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