linux-zen-server/drivers/pci/controller/dwc/pcie-bt1.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2021 BAIKAL ELECTRONICS, JSC
 *
 * Authors:
 *   Vadim Vlasov <Vadim.Vlasov@baikalelectronics.ru>
 *   Serge Semin <Sergey.Semin@baikalelectronics.ru>
 *
 * Baikal-T1 PCIe controller driver
 */

#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/reset.h>
#include <linux/types.h>

#include "pcie-designware.h"

/* Baikal-T1 System CCU control registers */
#define BT1_CCU_PCIE_CLKC			0x140
#define BT1_CCU_PCIE_REQ_PCS_CLK		BIT(16)
#define BT1_CCU_PCIE_REQ_MAC_CLK		BIT(17)
#define BT1_CCU_PCIE_REQ_PIPE_CLK		BIT(18)

#define BT1_CCU_PCIE_RSTC			0x144
#define BT1_CCU_PCIE_REQ_LINK_RST		BIT(13)
#define BT1_CCU_PCIE_REQ_SMLH_RST		BIT(14)
#define BT1_CCU_PCIE_REQ_PHY_RST		BIT(16)
#define BT1_CCU_PCIE_REQ_CORE_RST		BIT(24)
#define BT1_CCU_PCIE_REQ_STICKY_RST		BIT(26)
#define BT1_CCU_PCIE_REQ_NSTICKY_RST		BIT(27)

#define BT1_CCU_PCIE_PMSC			0x148
#define BT1_CCU_PCIE_LTSSM_STATE_MASK		GENMASK(5, 0)
#define BT1_CCU_PCIE_LTSSM_DET_QUIET		0x00
#define BT1_CCU_PCIE_LTSSM_DET_ACT		0x01
#define BT1_CCU_PCIE_LTSSM_POLL_ACT		0x02
#define BT1_CCU_PCIE_LTSSM_POLL_COMP		0x03
#define BT1_CCU_PCIE_LTSSM_POLL_CONF		0x04
#define BT1_CCU_PCIE_LTSSM_PRE_DET_QUIET	0x05
#define BT1_CCU_PCIE_LTSSM_DET_WAIT		0x06
#define BT1_CCU_PCIE_LTSSM_CFG_LNKWD_START	0x07
#define BT1_CCU_PCIE_LTSSM_CFG_LNKWD_ACEPT	0x08
#define BT1_CCU_PCIE_LTSSM_CFG_LNNUM_WAIT	0x09
#define BT1_CCU_PCIE_LTSSM_CFG_LNNUM_ACEPT	0x0a
#define BT1_CCU_PCIE_LTSSM_CFG_COMPLETE		0x0b
#define BT1_CCU_PCIE_LTSSM_CFG_IDLE		0x0c
#define BT1_CCU_PCIE_LTSSM_RCVR_LOCK		0x0d
#define BT1_CCU_PCIE_LTSSM_RCVR_SPEED		0x0e
#define BT1_CCU_PCIE_LTSSM_RCVR_RCVRCFG		0x0f
#define BT1_CCU_PCIE_LTSSM_RCVR_IDLE		0x10
#define BT1_CCU_PCIE_LTSSM_L0			0x11
#define BT1_CCU_PCIE_LTSSM_L0S			0x12
#define BT1_CCU_PCIE_LTSSM_L123_SEND_IDLE	0x13
#define BT1_CCU_PCIE_LTSSM_L1_IDLE		0x14
#define BT1_CCU_PCIE_LTSSM_L2_IDLE		0x15
#define BT1_CCU_PCIE_LTSSM_L2_WAKE		0x16
#define BT1_CCU_PCIE_LTSSM_DIS_ENTRY		0x17
#define BT1_CCU_PCIE_LTSSM_DIS_IDLE		0x18
#define BT1_CCU_PCIE_LTSSM_DISABLE		0x19
#define BT1_CCU_PCIE_LTSSM_LPBK_ENTRY		0x1a
#define BT1_CCU_PCIE_LTSSM_LPBK_ACTIVE		0x1b
#define BT1_CCU_PCIE_LTSSM_LPBK_EXIT		0x1c
#define BT1_CCU_PCIE_LTSSM_LPBK_EXIT_TOUT	0x1d
#define BT1_CCU_PCIE_LTSSM_HOT_RST_ENTRY	0x1e
#define BT1_CCU_PCIE_LTSSM_HOT_RST		0x1f
#define BT1_CCU_PCIE_LTSSM_RCVR_EQ0		0x20
#define BT1_CCU_PCIE_LTSSM_RCVR_EQ1		0x21
#define BT1_CCU_PCIE_LTSSM_RCVR_EQ2		0x22
#define BT1_CCU_PCIE_LTSSM_RCVR_EQ3		0x23
#define BT1_CCU_PCIE_SMLH_LINKUP		BIT(6)
#define BT1_CCU_PCIE_RDLH_LINKUP		BIT(7)
#define BT1_CCU_PCIE_PM_LINKSTATE_L0S		BIT(8)
#define BT1_CCU_PCIE_PM_LINKSTATE_L1		BIT(9)
#define BT1_CCU_PCIE_PM_LINKSTATE_L2		BIT(10)
#define BT1_CCU_PCIE_L1_PENDING			BIT(12)
#define BT1_CCU_PCIE_REQ_EXIT_L1		BIT(14)
#define BT1_CCU_PCIE_LTSSM_RCVR_EQ		BIT(15)
#define BT1_CCU_PCIE_PM_DSTAT_MASK		GENMASK(18, 16)
#define BT1_CCU_PCIE_PM_PME_EN			BIT(20)
#define BT1_CCU_PCIE_PM_PME_STATUS		BIT(21)
#define BT1_CCU_PCIE_AUX_PM_EN			BIT(22)
#define BT1_CCU_PCIE_AUX_PWR_DET		BIT(23)
#define BT1_CCU_PCIE_WAKE_DET			BIT(24)
#define BT1_CCU_PCIE_TURNOFF_REQ		BIT(30)
#define BT1_CCU_PCIE_TURNOFF_ACK		BIT(31)

#define BT1_CCU_PCIE_GENC			0x14c
#define BT1_CCU_PCIE_LTSSM_EN			BIT(1)
#define BT1_CCU_PCIE_DBI2_MODE			BIT(2)
#define BT1_CCU_PCIE_MGMT_EN			BIT(3)
#define BT1_CCU_PCIE_RXLANE_FLIP_EN		BIT(16)
#define BT1_CCU_PCIE_TXLANE_FLIP_EN		BIT(17)
#define BT1_CCU_PCIE_SLV_XFER_PEND		BIT(24)
#define BT1_CCU_PCIE_RCV_XFER_PEND		BIT(25)
#define BT1_CCU_PCIE_DBI_XFER_PEND		BIT(26)
#define BT1_CCU_PCIE_DMA_XFER_PEND		BIT(27)

#define BT1_CCU_PCIE_LTSSM_LINKUP(_pmsc) \
({ \
	int __state = FIELD_GET(BT1_CCU_PCIE_LTSSM_STATE_MASK, _pmsc); \
	__state >= BT1_CCU_PCIE_LTSSM_L0 && __state <= BT1_CCU_PCIE_LTSSM_L2_WAKE; \
})

/* Baikal-T1 PCIe specific control registers */
#define BT1_PCIE_AXI2MGM_LANENUM		0xd04
#define BT1_PCIE_AXI2MGM_LANESEL_MASK		GENMASK(3, 0)

#define BT1_PCIE_AXI2MGM_ADDRCTL		0xd08
#define BT1_PCIE_AXI2MGM_PHYREG_ADDR_MASK	GENMASK(20, 0)
#define BT1_PCIE_AXI2MGM_READ_FLAG		BIT(29)
#define BT1_PCIE_AXI2MGM_DONE			BIT(30)
#define BT1_PCIE_AXI2MGM_BUSY			BIT(31)

#define BT1_PCIE_AXI2MGM_WRITEDATA		0xd0c
#define BT1_PCIE_AXI2MGM_WDATA			GENMASK(15, 0)

#define BT1_PCIE_AXI2MGM_READDATA		0xd10
#define BT1_PCIE_AXI2MGM_RDATA			GENMASK(15, 0)

/* Generic Baikal-T1 PCIe interface resources */
#define BT1_PCIE_NUM_APP_CLKS			ARRAY_SIZE(bt1_pcie_app_clks)
#define BT1_PCIE_NUM_CORE_CLKS			ARRAY_SIZE(bt1_pcie_core_clks)
#define BT1_PCIE_NUM_APP_RSTS			ARRAY_SIZE(bt1_pcie_app_rsts)
#define BT1_PCIE_NUM_CORE_RSTS			ARRAY_SIZE(bt1_pcie_core_rsts)

/* PCIe bus setup delays and timeouts */
#define BT1_PCIE_RST_DELAY_MS			100
#define BT1_PCIE_RUN_DELAY_US			100
#define BT1_PCIE_REQ_DELAY_US			1
#define BT1_PCIE_REQ_TIMEOUT_US			1000
#define BT1_PCIE_LNK_DELAY_US			1000
#define BT1_PCIE_LNK_TIMEOUT_US			1000000

static const enum dw_pcie_app_clk bt1_pcie_app_clks[] = {
	DW_PCIE_DBI_CLK, DW_PCIE_MSTR_CLK, DW_PCIE_SLV_CLK,
};

static const enum dw_pcie_core_clk bt1_pcie_core_clks[] = {
	DW_PCIE_REF_CLK,
};

static const enum dw_pcie_app_rst bt1_pcie_app_rsts[] = {
	DW_PCIE_MSTR_RST, DW_PCIE_SLV_RST,
};

static const enum dw_pcie_core_rst bt1_pcie_core_rsts[] = {
	DW_PCIE_NON_STICKY_RST, DW_PCIE_STICKY_RST, DW_PCIE_CORE_RST,
	DW_PCIE_PIPE_RST, DW_PCIE_PHY_RST, DW_PCIE_HOT_RST, DW_PCIE_PWR_RST,
};

struct bt1_pcie {
	struct dw_pcie dw;
	struct platform_device *pdev;
	struct regmap *sys_regs;
};
#define to_bt1_pcie(_dw) container_of(_dw, struct bt1_pcie, dw)

/*
 * Baikal-T1 MMIO space must be read/written by the dword-aligned
 * instructions. Note the methods are optimized to have the dword operations
 * performed with minimum overhead as the most frequently used ones.
 */
static int bt1_pcie_read_mmio(void __iomem *addr, int size, u32 *val)
{
	unsigned int ofs = (uintptr_t)addr & 0x3;

	if (!IS_ALIGNED((uintptr_t)addr, size))
		return -EINVAL;

	*val = readl(addr - ofs) >> ofs * BITS_PER_BYTE;
	if (size == 4) {
		return 0;
	} else if (size == 2) {
		*val &= 0xffff;
		return 0;
	} else if (size == 1) {
		*val &= 0xff;
		return 0;
	}

	return -EINVAL;
}

static int bt1_pcie_write_mmio(void __iomem *addr, int size, u32 val)
{
	unsigned int ofs = (uintptr_t)addr & 0x3;
	u32 tmp, mask;

	if (!IS_ALIGNED((uintptr_t)addr, size))
		return -EINVAL;

	if (size == 4) {
		writel(val, addr);
		return 0;
	} else if (size == 2 || size == 1) {
		mask = GENMASK(size * BITS_PER_BYTE - 1, 0);
		tmp = readl(addr - ofs) & ~(mask << ofs * BITS_PER_BYTE);
		tmp |= (val & mask) << ofs * BITS_PER_BYTE;
		writel(tmp, addr - ofs);
		return 0;
	}

	return -EINVAL;
}

static u32 bt1_pcie_read_dbi(struct dw_pcie *pci, void __iomem *base, u32 reg,
			     size_t size)
{
	int ret;
	u32 val;

	ret = bt1_pcie_read_mmio(base + reg, size, &val);
	if (ret) {
		dev_err(pci->dev, "Read DBI address failed\n");
		return ~0U;
	}

	return val;
}

static void bt1_pcie_write_dbi(struct dw_pcie *pci, void __iomem *base, u32 reg,
			       size_t size, u32 val)
{
	int ret;

	ret = bt1_pcie_write_mmio(base + reg, size, val);
	if (ret)
		dev_err(pci->dev, "Write DBI address failed\n");
}

static void bt1_pcie_write_dbi2(struct dw_pcie *pci, void __iomem *base, u32 reg,
				size_t size, u32 val)
{
	struct bt1_pcie *btpci = to_bt1_pcie(pci);
	int ret;

	regmap_update_bits(btpci->sys_regs, BT1_CCU_PCIE_GENC,
			   BT1_CCU_PCIE_DBI2_MODE, BT1_CCU_PCIE_DBI2_MODE);

	ret = bt1_pcie_write_mmio(base + reg, size, val);
	if (ret)
		dev_err(pci->dev, "Write DBI2 address failed\n");

	regmap_update_bits(btpci->sys_regs, BT1_CCU_PCIE_GENC,
			   BT1_CCU_PCIE_DBI2_MODE, 0);
}

static int bt1_pcie_start_link(struct dw_pcie *pci)
{
	struct bt1_pcie *btpci = to_bt1_pcie(pci);
	u32 val;
	int ret;

	/*
	 * Enable LTSSM and make sure it was able to establish both PHY and
	 * data links. This procedure shall work fine to reach 2.5 GT/s speed.
	 */
	regmap_update_bits(btpci->sys_regs, BT1_CCU_PCIE_GENC,
			   BT1_CCU_PCIE_LTSSM_EN, BT1_CCU_PCIE_LTSSM_EN);

	ret = regmap_read_poll_timeout(btpci->sys_regs, BT1_CCU_PCIE_PMSC, val,
				       (val & BT1_CCU_PCIE_SMLH_LINKUP),
				       BT1_PCIE_LNK_DELAY_US, BT1_PCIE_LNK_TIMEOUT_US);
	if (ret) {
		dev_err(pci->dev, "LTSSM failed to set PHY link up\n");
		return ret;
	}

	ret = regmap_read_poll_timeout(btpci->sys_regs, BT1_CCU_PCIE_PMSC, val,
				       (val & BT1_CCU_PCIE_RDLH_LINKUP),
				       BT1_PCIE_LNK_DELAY_US, BT1_PCIE_LNK_TIMEOUT_US);
	if (ret) {
		dev_err(pci->dev, "LTSSM failed to set data link up\n");
		return ret;
	}

	/*
	 * Activate direct speed change after the link is established in an
	 * attempt to reach a higher bus performance (up to Gen.3 - 8.0 GT/s).
	 * This is required at least to get 8.0 GT/s speed.
	 */
	val = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
	val |= PORT_LOGIC_SPEED_CHANGE;
	dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, val);

	ret = regmap_read_poll_timeout(btpci->sys_regs, BT1_CCU_PCIE_PMSC, val,
				       BT1_CCU_PCIE_LTSSM_LINKUP(val),
				       BT1_PCIE_LNK_DELAY_US, BT1_PCIE_LNK_TIMEOUT_US);
	if (ret)
		dev_err(pci->dev, "LTSSM failed to get into L0 state\n");

	return ret;
}

static void bt1_pcie_stop_link(struct dw_pcie *pci)
{
	struct bt1_pcie *btpci = to_bt1_pcie(pci);

	regmap_update_bits(btpci->sys_regs, BT1_CCU_PCIE_GENC,
			   BT1_CCU_PCIE_LTSSM_EN, 0);
}

static const struct dw_pcie_ops bt1_pcie_ops = {
	.read_dbi = bt1_pcie_read_dbi,
	.write_dbi = bt1_pcie_write_dbi,
	.write_dbi2 = bt1_pcie_write_dbi2,
	.start_link = bt1_pcie_start_link,
	.stop_link = bt1_pcie_stop_link,
};

static struct pci_ops bt1_pci_ops = {
	.map_bus = dw_pcie_own_conf_map_bus,
	.read = pci_generic_config_read32,
	.write = pci_generic_config_write32,
};

static int bt1_pcie_get_resources(struct bt1_pcie *btpci)
{
	struct device *dev = btpci->dw.dev;
	int i;

	/* DBI access is supposed to be performed by the dword-aligned IOs */
	btpci->dw.pp.bridge->ops = &bt1_pci_ops;

	/* These CSRs are in MMIO so we won't check the regmap-methods status */
	btpci->sys_regs =
		syscon_regmap_lookup_by_phandle(dev->of_node, "baikal,bt1-syscon");
	if (IS_ERR(btpci->sys_regs))
		return dev_err_probe(dev, PTR_ERR(btpci->sys_regs),
				     "Failed to get syscon\n");

	/* Make sure all the required resources have been specified */
	for (i = 0; i < BT1_PCIE_NUM_APP_CLKS; i++) {
		if (!btpci->dw.app_clks[bt1_pcie_app_clks[i]].clk) {
			dev_err(dev, "App clocks set is incomplete\n");
			return -ENOENT;
		}
	}

	for (i = 0; i < BT1_PCIE_NUM_CORE_CLKS; i++) {
		if (!btpci->dw.core_clks[bt1_pcie_core_clks[i]].clk) {
			dev_err(dev, "Core clocks set is incomplete\n");
			return -ENOENT;
		}
	}

	for (i = 0; i < BT1_PCIE_NUM_APP_RSTS; i++) {
		if (!btpci->dw.app_rsts[bt1_pcie_app_rsts[i]].rstc) {
			dev_err(dev, "App resets set is incomplete\n");
			return -ENOENT;
		}
	}

	for (i = 0; i < BT1_PCIE_NUM_CORE_RSTS; i++) {
		if (!btpci->dw.core_rsts[bt1_pcie_core_rsts[i]].rstc) {
			dev_err(dev, "Core resets set is incomplete\n");
			return -ENOENT;
		}
	}

	return 0;
}

static void bt1_pcie_full_stop_bus(struct bt1_pcie *btpci, bool init)
{
	struct device *dev = btpci->dw.dev;
	struct dw_pcie *pci = &btpci->dw;
	int ret;

	/* Disable LTSSM for sure */
	regmap_update_bits(btpci->sys_regs, BT1_CCU_PCIE_GENC,
			   BT1_CCU_PCIE_LTSSM_EN, 0);

	/*
	 * Application reset controls are trigger-based so assert the core
	 * resets only.
	 */
	ret = reset_control_bulk_assert(DW_PCIE_NUM_CORE_RSTS, pci->core_rsts);
	if (ret)
		dev_err(dev, "Failed to assert core resets\n");

	/*
	 * Clocks are disabled by default at least in accordance with the clk
	 * enable counter value on init stage.
	 */
	if (!init) {
		clk_bulk_disable_unprepare(DW_PCIE_NUM_CORE_CLKS, pci->core_clks);

		clk_bulk_disable_unprepare(DW_PCIE_NUM_APP_CLKS, pci->app_clks);
	}

	/* The peripheral devices are unavailable anyway so reset them too */
	gpiod_set_value_cansleep(pci->pe_rst, 1);

	/* Make sure all the resets are settled */
	msleep(BT1_PCIE_RST_DELAY_MS);
}

/*
 * Implements the cold reset procedure in accordance with the reference manual
 * and available PM signals.
 */
static int bt1_pcie_cold_start_bus(struct bt1_pcie *btpci)
{
	struct device *dev = btpci->dw.dev;
	struct dw_pcie *pci = &btpci->dw;
	u32 val;
	int ret;

	/* First get out of the Power/Hot reset state */
	ret = reset_control_deassert(pci->core_rsts[DW_PCIE_PWR_RST].rstc);
	if (ret) {
		dev_err(dev, "Failed to deassert PHY reset\n");
		return ret;
	}

	ret = reset_control_deassert(pci->core_rsts[DW_PCIE_HOT_RST].rstc);
	if (ret) {
		dev_err(dev, "Failed to deassert hot reset\n");
		goto err_assert_pwr_rst;
	}

	/* Wait for the PM-core to stop requesting the PHY reset */
	ret = regmap_read_poll_timeout(btpci->sys_regs, BT1_CCU_PCIE_RSTC, val,
				       !(val & BT1_CCU_PCIE_REQ_PHY_RST),
				       BT1_PCIE_REQ_DELAY_US, BT1_PCIE_REQ_TIMEOUT_US);
	if (ret) {
		dev_err(dev, "Timed out waiting for PM to stop PHY resetting\n");
		goto err_assert_hot_rst;
	}

	ret = reset_control_deassert(pci->core_rsts[DW_PCIE_PHY_RST].rstc);
	if (ret) {
		dev_err(dev, "Failed to deassert PHY reset\n");
		goto err_assert_hot_rst;
	}

	/* Clocks can be now enabled, but the ref one is crucial at this stage */
	ret = clk_bulk_prepare_enable(DW_PCIE_NUM_APP_CLKS, pci->app_clks);
	if (ret) {
		dev_err(dev, "Failed to enable app clocks\n");
		goto err_assert_phy_rst;
	}

	ret = clk_bulk_prepare_enable(DW_PCIE_NUM_CORE_CLKS, pci->core_clks);
	if (ret) {
		dev_err(dev, "Failed to enable ref clocks\n");
		goto err_disable_app_clk;
	}

	/* Wait for the PM to stop requesting the controller core reset */
	ret = regmap_read_poll_timeout(btpci->sys_regs, BT1_CCU_PCIE_RSTC, val,
				       !(val & BT1_CCU_PCIE_REQ_CORE_RST),
				       BT1_PCIE_REQ_DELAY_US, BT1_PCIE_REQ_TIMEOUT_US);
	if (ret) {
		dev_err(dev, "Timed out waiting for PM to stop core resetting\n");
		goto err_disable_core_clk;
	}

	/* PCS-PIPE interface and controller core can be now activated */
	ret = reset_control_deassert(pci->core_rsts[DW_PCIE_PIPE_RST].rstc);
	if (ret) {
		dev_err(dev, "Failed to deassert PIPE reset\n");
		goto err_disable_core_clk;
	}

	ret = reset_control_deassert(pci->core_rsts[DW_PCIE_CORE_RST].rstc);
	if (ret) {
		dev_err(dev, "Failed to deassert core reset\n");
		goto err_assert_pipe_rst;
	}

	/* It's recommended to reset the core and application logic together */
	ret = reset_control_bulk_reset(DW_PCIE_NUM_APP_RSTS, pci->app_rsts);
	if (ret) {
		dev_err(dev, "Failed to reset app domain\n");
		goto err_assert_core_rst;
	}

	/* Sticky/Non-sticky CSR flags can be now unreset too */
	ret = reset_control_deassert(pci->core_rsts[DW_PCIE_STICKY_RST].rstc);
	if (ret) {
		dev_err(dev, "Failed to deassert sticky reset\n");
		goto err_assert_core_rst;
	}

	ret = reset_control_deassert(pci->core_rsts[DW_PCIE_NON_STICKY_RST].rstc);
	if (ret) {
		dev_err(dev, "Failed to deassert non-sticky reset\n");
		goto err_assert_sticky_rst;
	}

	/* Activate the PCIe bus peripheral devices */
	gpiod_set_value_cansleep(pci->pe_rst, 0);

	/* Make sure the state is settled (LTSSM is still disabled though) */
	usleep_range(BT1_PCIE_RUN_DELAY_US, BT1_PCIE_RUN_DELAY_US + 100);

	return 0;

err_assert_sticky_rst:
	reset_control_assert(pci->core_rsts[DW_PCIE_STICKY_RST].rstc);

err_assert_core_rst:
	reset_control_assert(pci->core_rsts[DW_PCIE_CORE_RST].rstc);

err_assert_pipe_rst:
	reset_control_assert(pci->core_rsts[DW_PCIE_PIPE_RST].rstc);

err_disable_core_clk:
	clk_bulk_disable_unprepare(DW_PCIE_NUM_CORE_CLKS, pci->core_clks);

err_disable_app_clk:
	clk_bulk_disable_unprepare(DW_PCIE_NUM_APP_CLKS, pci->app_clks);

err_assert_phy_rst:
	reset_control_assert(pci->core_rsts[DW_PCIE_PHY_RST].rstc);

err_assert_hot_rst:
	reset_control_assert(pci->core_rsts[DW_PCIE_HOT_RST].rstc);

err_assert_pwr_rst:
	reset_control_assert(pci->core_rsts[DW_PCIE_PWR_RST].rstc);

	return ret;
}

static int bt1_pcie_host_init(struct dw_pcie_rp *pp)
{
	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
	struct bt1_pcie *btpci = to_bt1_pcie(pci);
	int ret;

	ret = bt1_pcie_get_resources(btpci);
	if (ret)
		return ret;

	bt1_pcie_full_stop_bus(btpci, true);

	return bt1_pcie_cold_start_bus(btpci);
}

static void bt1_pcie_host_deinit(struct dw_pcie_rp *pp)
{
	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
	struct bt1_pcie *btpci = to_bt1_pcie(pci);

	bt1_pcie_full_stop_bus(btpci, false);
}

static const struct dw_pcie_host_ops bt1_pcie_host_ops = {
	.host_init = bt1_pcie_host_init,
	.host_deinit = bt1_pcie_host_deinit,
};

static struct bt1_pcie *bt1_pcie_create_data(struct platform_device *pdev)
{
	struct bt1_pcie *btpci;

	btpci = devm_kzalloc(&pdev->dev, sizeof(*btpci), GFP_KERNEL);
	if (!btpci)
		return ERR_PTR(-ENOMEM);

	btpci->pdev = pdev;

	platform_set_drvdata(pdev, btpci);

	return btpci;
}

static int bt1_pcie_add_port(struct bt1_pcie *btpci)
{
	struct device *dev = &btpci->pdev->dev;
	int ret;

	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
	if (ret)
		return ret;

	btpci->dw.version = DW_PCIE_VER_460A;
	btpci->dw.dev = dev;
	btpci->dw.ops = &bt1_pcie_ops;

	btpci->dw.pp.num_vectors = MAX_MSI_IRQS;
	btpci->dw.pp.ops = &bt1_pcie_host_ops;

	dw_pcie_cap_set(&btpci->dw, REQ_RES);

	ret = dw_pcie_host_init(&btpci->dw.pp);

	return dev_err_probe(dev, ret, "Failed to initialize DWC PCIe host\n");
}

static void bt1_pcie_del_port(struct bt1_pcie *btpci)
{
	dw_pcie_host_deinit(&btpci->dw.pp);
}

static int bt1_pcie_probe(struct platform_device *pdev)
{
	struct bt1_pcie *btpci;

	btpci = bt1_pcie_create_data(pdev);
	if (IS_ERR(btpci))
		return PTR_ERR(btpci);

	return bt1_pcie_add_port(btpci);
}

static int bt1_pcie_remove(struct platform_device *pdev)
{
	struct bt1_pcie *btpci = platform_get_drvdata(pdev);

	bt1_pcie_del_port(btpci);

	return 0;
}

static const struct of_device_id bt1_pcie_of_match[] = {
	{ .compatible = "baikal,bt1-pcie" },
	{},
};
MODULE_DEVICE_TABLE(of, bt1_pcie_of_match);

static struct platform_driver bt1_pcie_driver = {
	.probe = bt1_pcie_probe,
	.remove = bt1_pcie_remove,
	.driver = {
		.name	= "bt1-pcie",
		.of_match_table = bt1_pcie_of_match,
	},
};
module_platform_driver(bt1_pcie_driver);

MODULE_AUTHOR("Serge Semin <Sergey.Semin@baikalelectronics.ru>");
MODULE_DESCRIPTION("Baikal-T1 PCIe driver");
MODULE_LICENSE("GPL");