U-Boot

// SPDX-License-Identifier: GPL-2.0-only OR MIT
/*
 * Copyright (C) 2025 Texas Instruments Incorporated - https://www.ti.com
 *
 * PCIe Endpoint controller driver for TI's K3 SoCs with Cadence PCIe controller
 *
 * Ported from the Linux driver - drivers/pci/controller/cadence/pci-j721e.c
 *
 * Author: Hrushikesh Salunke <h-salunke@ti.com>
 *
 */

#include <clk.h>
#include <dm.h>
#include <dm/device_compat.h>
#include <generic-phy.h>
#include <linux/log2.h>
#include <linux/sizes.h>
#include <power-domain.h>
#include <regmap.h>
#include <syscon.h>
#include <pci_ep.h>
#include <linux/delay.h>

#include "pcie-cadence.h"

#define PCIE_USER_CMD_STATUS_REG_OFFSET	0x4
#define LINK_TRAINING_ENABLE			BIT(0)

#define PCIE_MODE_SEL_MASK			BIT(7)
#define PCIE_GEN_SEL_MASK			GENMASK(1, 0)
#define PCIE_LINK_WIDTH_MASK			GENMASK(9, 8)

struct pcie_cdns_ti_ep_data {
	unsigned int		quirk_retrain_flag:1;
	unsigned int		quirk_detect_quiet_flag:1;
	unsigned int		quirk_disable_flr:1;
	unsigned int		byte_access_allowed:1;
	unsigned int		max_lanes;
};

struct pcie_cdns_ti_ep {
	struct udevice		*dev;
	void __iomem		*intd_cfg_base;
	void __iomem		*user_cfg_base;
	void __iomem		*reg_base;
	void __iomem		*mem_base;
	fdt_size_t		cfg_size;
	struct regmap		*syscon_base;
	u32			max_link_speed;
	u32			num_lanes;
	u32			pcie_ctrl_offset;
	unsigned int		quirk_retrain_flag:1;
	unsigned int		quirk_detect_quiet_flag:1;
	unsigned int		quirk_disable_flr:1;
	unsigned int		byte_access_allowed:1;
};

static inline u32 pcie_cdns_ti_ep_user_readl(struct pcie_cdns_ti_ep *pcie, u32 offset)
{
	return readl(pcie->user_cfg_base + offset);
}

static inline void pcie_cdns_ti_ep_user_writel(struct pcie_cdns_ti_ep *pcie, u32 offset,
					       u32 val)
{
	writel(val, pcie->user_cfg_base + offset);
}

static void pcie_cdns_ti_start_link(struct pcie_cdns_ti_ep *pcie)
{
	u32 reg;

	reg = pcie_cdns_ti_ep_user_readl(pcie, PCIE_USER_CMD_STATUS_REG_OFFSET);
	reg |= LINK_TRAINING_ENABLE;
	pcie_cdns_ti_ep_user_writel(pcie, PCIE_USER_CMD_STATUS_REG_OFFSET, reg);
}

static int pcie_cdns_reset(struct udevice *dev, struct power_domain *pci_pwrdmn)
{
	int ret;

	ret = power_domain_off(pci_pwrdmn);
	if (ret) {
		dev_err(dev, "failed to power off\n");
		return ret;
	}

	ret = power_domain_on(pci_pwrdmn);
	if (ret) {
		dev_err(dev, "failed to power on: %d\n", ret);
		return ret;
	}
	mdelay(1);
	return 0;
}

static int pcie_cdns_config_serdes(struct udevice *dev)
{
	int ret;

	if (CONFIG_IS_ENABLED(MUX_MMIO)) {
		struct udevice *mux;

		ret = uclass_get_device_by_seq(UCLASS_MUX, 0, &mux);
		if (ret) {
			dev_err(dev, "unable to get mux\n");
			return ret;
		}
	}

	if (CONFIG_IS_ENABLED(PHY_CADENCE_TORRENT)) {
		struct phy serdes;

		ret = generic_phy_get_by_name(dev,  "pcie-phy", &serdes);
		if (ret != 0 && ret != -EBUSY) {
			dev_err(dev, "unable to get serdes\n");
			return ret;
		}
		generic_phy_reset(&serdes);
		generic_phy_init(&serdes);
		generic_phy_power_on(&serdes);
	} else {
		dev_info(dev, "Proceeding with the assumption that the SERDES is already configured\n");
	}
	return 0;
}

static int pcie_cdns_ti_ctrl_init(struct pcie_cdns_ti_ep *pcie)
{
	struct regmap *syscon = pcie->syscon_base;
	u32 val = 0;

	/* Set mode of operation */
	regmap_update_bits(syscon, pcie->pcie_ctrl_offset, PCIE_MODE_SEL_MASK,
			   val);

	/* Set link speed */
	regmap_update_bits(syscon, pcie->pcie_ctrl_offset, PCIE_GEN_SEL_MASK,
			   pcie->max_link_speed - 1);

	/* Set link width */
	regmap_update_bits(syscon, pcie->pcie_ctrl_offset, PCIE_LINK_WIDTH_MASK,
			   (pcie->num_lanes - 1) << 8);
	return 0;
}

static int pcie_cdns_ti_write_header(struct udevice *dev, uint fn,
				     struct pci_ep_header *hdr)
{
	struct pcie_cdns_ti_ep *pcie_ep = dev_get_priv(dev);
	struct cdns_pcie pcie;

	pcie.reg_base = pcie_ep->reg_base;

	cdns_pcie_ep_fn_writew(&pcie, fn, PCI_DEVICE_ID, hdr->deviceid);
	cdns_pcie_ep_fn_writeb(&pcie, fn, PCI_REVISION_ID, hdr->revid);
	cdns_pcie_ep_fn_writeb(&pcie, fn, PCI_CLASS_PROG,
			       hdr->progif_code);
	cdns_pcie_ep_fn_writew(&pcie, fn, PCI_CLASS_DEVICE,
			       hdr->subclass_code |
			       hdr->baseclass_code << 8);
	cdns_pcie_ep_fn_writeb(&pcie, fn, PCI_CACHE_LINE_SIZE,
			       hdr->cache_line_size);
	cdns_pcie_ep_fn_writew(&pcie, fn, PCI_SUBSYSTEM_ID,
			       hdr->subsys_id);
	cdns_pcie_ep_fn_writeb(&pcie, fn, PCI_INTERRUPT_PIN,
			       hdr->interrupt_pin);

	/*
	 * Vendor ID can only be modified from function 0, all other functions
	 * use the same vendor ID as function 0.
	 */
	if (fn == 0) {
		/* Update the vendor IDs. */
		u32 id = CDNS_PCIE_LM_ID_VENDOR(hdr->vendorid) |
			 CDNS_PCIE_LM_ID_SUBSYS(hdr->subsys_vendor_id);

		cdns_pcie_writel(&pcie, CDNS_PCIE_LM_ID, id);
	}

	return 0;
}

static int pcie_cdns_ti_set_bar(struct udevice *dev, uint fn,
				struct pci_bar *ep_bar)
{
	struct pcie_cdns_ti_ep *pcie_ep = dev_get_priv(dev);
	struct cdns_pcie pcie;
	dma_addr_t bar_phys = ep_bar->phys_addr;
	enum pci_barno bar = ep_bar->barno;
	int flags = ep_bar->flags;
	u32 addr0, addr1, reg, cfg, b, aperture, ctrl;
	u64 sz;

	pcie.reg_base = pcie_ep->reg_base;

	/* BAR size is 2^(aperture + 7) */
	sz = max_t(size_t, ep_bar->size, CDNS_PCIE_EP_MIN_APERTURE);
	/*
	 * roundup_pow_of_two() returns an unsigned long, which is not suited
	 * for 64bit values.
	 */
	sz = 1ULL << fls64(sz - 1);
	aperture = ilog2(sz) - 7; /* 128B -> 0, 256B -> 1, 512B -> 2, ... */

	if ((flags & PCI_BASE_ADDRESS_SPACE) == PCI_BASE_ADDRESS_SPACE_IO) {
		ctrl = CDNS_PCIE_LM_BAR_CFG_CTRL_IO_32BITS;
	} else {
		bool is_prefetch = !!(flags & PCI_BASE_ADDRESS_MEM_PREFETCH);
		bool is_64bits = (sz > SZ_2G) |
			!!(ep_bar->flags & PCI_BASE_ADDRESS_MEM_TYPE_64);

		if (is_64bits && (bar & 1))
			return -EINVAL;

		if (is_64bits && !(flags & PCI_BASE_ADDRESS_MEM_TYPE_64))
			ep_bar->flags |= PCI_BASE_ADDRESS_MEM_TYPE_64;

		if (is_64bits && is_prefetch)
			ctrl = CDNS_PCIE_LM_BAR_CFG_CTRL_PREFETCH_MEM_64BITS;
		else if (is_prefetch)
			ctrl = CDNS_PCIE_LM_BAR_CFG_CTRL_PREFETCH_MEM_32BITS;
		else if (is_64bits)
			ctrl = CDNS_PCIE_LM_BAR_CFG_CTRL_MEM_64BITS;
		else
			ctrl = CDNS_PCIE_LM_BAR_CFG_CTRL_MEM_32BITS;
	}

	addr0 = lower_32_bits(bar_phys);
	addr1 = upper_32_bits(bar_phys);
	cdns_pcie_writel(&pcie, CDNS_PCIE_AT_IB_EP_FUNC_BAR_ADDR0(fn, bar),
			 addr0);
	cdns_pcie_writel(&pcie, CDNS_PCIE_AT_IB_EP_FUNC_BAR_ADDR1(fn, bar),
			 addr1);

	/*
	 * Cadence PCIe controller provides a register interface to configure
	 * BAR of an Endpoint function. Per function there are two BAR configuration
	 * registers, out of which first is used to configure BAR_0 to BAR_4 and
	 * second is used to configure the remaining BARs.
	 */
	if (bar < BAR_4) {
		reg = CDNS_PCIE_LM_EP_FUNC_BAR_CFG0(fn);
		b = bar;
	} else {
		reg = CDNS_PCIE_LM_EP_FUNC_BAR_CFG1(fn);
		b = bar - BAR_4;
	}

	cfg = cdns_pcie_readl(&pcie, reg);

	cfg &= ~(CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_APERTURE_MASK(b) |
		 CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL_MASK(b));
	cfg |= (CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_APERTURE(b, aperture) |
		CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL(b, ctrl));
	cdns_pcie_writel(&pcie, reg, cfg);

	cfg = cdns_pcie_readl(&pcie, reg);

	return 0;
}

static int pcie_cdns_ti_start(struct udevice *dev)
{
	struct pcie_cdns_ti_ep *pcie = dev_get_priv(dev);

	pcie_cdns_ti_start_link(pcie);

	return 0;
}

static int pcie_cdns_ti_ep_probe(struct udevice *dev)
{
	struct pcie_cdns_ti_ep *pcie = dev_get_priv(dev);
	struct pcie_cdns_ti_ep_data *data;
	struct power_domain pci_pwrdmn;
	struct cdns_pcie pcie_dev;
	struct clk *clk;
	int ret;

	pcie_dev.reg_base = pcie->reg_base;
	pcie->dev = dev;
	data = (struct pcie_cdns_ti_ep_data *)dev_get_driver_data(dev);
	if (!data)
		return -EINVAL;

	pcie->quirk_retrain_flag = data->quirk_retrain_flag;
	pcie->quirk_detect_quiet_flag = data->quirk_detect_quiet_flag;
	pcie->quirk_disable_flr = data->quirk_disable_flr;

	if (pcie->num_lanes > data->max_lanes) {
		dev_warn(dev, "cannot support %d lanes, defaulting to %d\n",
			 pcie->num_lanes, data->max_lanes);
		pcie->num_lanes = data->max_lanes;
	}

	ret = power_domain_get_by_index(dev, &pci_pwrdmn, 0);
	if (ret) {
		dev_err(dev, "failed to get power domain: %d\n", ret);
		return ret;
	}

	/*
	 * Reset the PCIe controller so that newly configured BAR
	 * values are reflected.
	 */
	ret = pcie_cdns_reset(dev, &pci_pwrdmn);
	if (ret) {
		dev_err(dev, "failed to reset controller: %d\n", ret);
		return ret;
	}

	clk = devm_clk_get(dev, "fck");
	if (IS_ERR(clk)) {
		ret = PTR_ERR(clk);
		dev_err(dev, "failed to get functional clock\n");
		return ret;
	}

	ret = pcie_cdns_config_serdes(dev);
	if (ret) {
		dev_err(dev, "failed to configure serdes: %d\n", ret);
		return ret;
	}

	ret = pcie_cdns_ti_ctrl_init(pcie);
	if (ret) {
		dev_err(dev, "failed to initialize controller: %d\n", ret);
		return ret;
	}

	/*
	 * Disable all the functions except function 0 (anyway BIT(0) is
	 * hardwired to 1). This is required to avoid RC from enumerating
	 * those functions which are not even configured.
	 */
	cdns_pcie_writel(&pcie_dev, CDNS_PCIE_LM_EP_FUNC_CFG, BIT(0));

	return 0;
}

static int pcie_cdns_ti_ep_of_to_plat(struct udevice *dev)
{
	struct pcie_cdns_ti_ep *pcie = dev_get_priv(dev);
	struct regmap *syscon;
	u32 offset;
	int ret;

	pcie->intd_cfg_base = dev_remap_addr_name(dev, "intd_cfg");
	if (!pcie->intd_cfg_base)
		return -EINVAL;

	pcie->user_cfg_base = dev_remap_addr_name(dev, "user_cfg");
	if (!pcie->user_cfg_base)
		return -EINVAL;

	pcie->reg_base = dev_remap_addr_name(dev, "reg");
	if (!pcie->reg_base)
		return -EINVAL;

	pcie->mem_base = dev_remap_addr_name(dev, "mem");
	if (!pcie->mem_base)
		return -EINVAL;

	ret = dev_read_u32(dev, "num-lanes", &pcie->num_lanes);
	if (ret)
		return ret;

	ret = dev_read_u32(dev, "max-link-speed", &pcie->max_link_speed);
	if (ret)
		return ret;

	syscon = syscon_regmap_lookup_by_phandle(dev, "ti,syscon-pcie-ctrl");
	if (IS_ERR(syscon)) {
		if (PTR_ERR(syscon) == -ENODEV)
			return 0;
		return PTR_ERR(syscon);
	}

	ret = dev_read_u32_index(dev, "ti,syscon-pcie-ctrl", 1, &offset);
	if (ret)
		return ret;

	pcie->syscon_base = syscon;
	pcie->pcie_ctrl_offset = offset;

	return 0;
}

static const struct pci_ep_ops pcie_cdns_ti_ep_ops = {
	.write_header = pcie_cdns_ti_write_header,
	.set_bar	  = pcie_cdns_ti_set_bar,
	.start	      = pcie_cdns_ti_start,
};

static const struct pcie_cdns_ti_ep_data am64_pcie_ep_data = {
	.max_lanes = 1,
};

static const struct pcie_cdns_ti_ep_data j784s4_pcie_ep_data = {
	.max_lanes = 4,
};

static const struct udevice_id pcie_cdns_ti_ep_ids[] = {
	{
		.compatible = "ti,am64-pcie-ep",
		.data = (ulong)&am64_pcie_ep_data,
	},
	{
		.compatible = "ti,j784s4-pcie-ep",
		.data = (ulong)&j784s4_pcie_ep_data,
	},
	{},
};

U_BOOT_DRIVER(pcie_cdns_ti_ep) = {
	.name			= "pcie_cdns_ti_ep",
	.id			    = UCLASS_PCI_EP,
	.of_match		= pcie_cdns_ti_ep_ids,
	.ops			= &pcie_cdns_ti_ep_ops,
	.of_to_plat		= pcie_cdns_ti_ep_of_to_plat,
	.probe			= pcie_cdns_ti_ep_probe,
	.priv_auto		= sizeof(struct pcie_cdns_ti_ep),
};