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- Drop redundant '-gpios' from DT GPIO lookup (Ben Dooks) - Force 2.5GT/s for initial device probe to workaround enumeration issue on SiFive Unmatched board (Ben Dooks) * pci/host/fu740: PCI: fu740: Force 2.5GT/s for initial device probe PCI: fu740: Drop redundant '-gpios' from DT GPIO lookup
358 lines
11 KiB
C
358 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* FU740 DesignWare PCIe Controller integration
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* Copyright (C) 2019-2021 SiFive, Inc.
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* Paul Walmsley
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* Greentime Hu
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*
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* Based in part on the i.MX6 PCIe host controller shim which is:
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*
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* Copyright (C) 2013 Kosagi
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* https://www.kosagi.com
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*/
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#include <linux/clk.h>
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#include <linux/delay.h>
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#include <linux/gpio.h>
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#include <linux/gpio/consumer.h>
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#include <linux/kernel.h>
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#include <linux/mfd/syscon.h>
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#include <linux/module.h>
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#include <linux/pci.h>
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#include <linux/platform_device.h>
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#include <linux/regulator/consumer.h>
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#include <linux/resource.h>
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#include <linux/types.h>
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#include <linux/interrupt.h>
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#include <linux/iopoll.h>
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#include <linux/reset.h>
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#include "pcie-designware.h"
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#define to_fu740_pcie(x) dev_get_drvdata((x)->dev)
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struct fu740_pcie {
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struct dw_pcie pci;
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void __iomem *mgmt_base;
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struct gpio_desc *reset;
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struct gpio_desc *pwren;
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struct clk *pcie_aux;
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struct reset_control *rst;
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};
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#define SIFIVE_DEVICESRESETREG 0x28
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#define PCIEX8MGMT_PERST_N 0x0
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#define PCIEX8MGMT_APP_LTSSM_ENABLE 0x10
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#define PCIEX8MGMT_APP_HOLD_PHY_RST 0x18
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#define PCIEX8MGMT_DEVICE_TYPE 0x708
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#define PCIEX8MGMT_PHY0_CR_PARA_ADDR 0x860
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#define PCIEX8MGMT_PHY0_CR_PARA_RD_EN 0x870
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#define PCIEX8MGMT_PHY0_CR_PARA_RD_DATA 0x878
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#define PCIEX8MGMT_PHY0_CR_PARA_SEL 0x880
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#define PCIEX8MGMT_PHY0_CR_PARA_WR_DATA 0x888
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#define PCIEX8MGMT_PHY0_CR_PARA_WR_EN 0x890
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#define PCIEX8MGMT_PHY0_CR_PARA_ACK 0x898
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#define PCIEX8MGMT_PHY1_CR_PARA_ADDR 0x8a0
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#define PCIEX8MGMT_PHY1_CR_PARA_RD_EN 0x8b0
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#define PCIEX8MGMT_PHY1_CR_PARA_RD_DATA 0x8b8
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#define PCIEX8MGMT_PHY1_CR_PARA_SEL 0x8c0
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#define PCIEX8MGMT_PHY1_CR_PARA_WR_DATA 0x8c8
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#define PCIEX8MGMT_PHY1_CR_PARA_WR_EN 0x8d0
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#define PCIEX8MGMT_PHY1_CR_PARA_ACK 0x8d8
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#define PCIEX8MGMT_PHY_CDR_TRACK_EN BIT(0)
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#define PCIEX8MGMT_PHY_LOS_THRSHLD BIT(5)
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#define PCIEX8MGMT_PHY_TERM_EN BIT(9)
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#define PCIEX8MGMT_PHY_TERM_ACDC BIT(10)
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#define PCIEX8MGMT_PHY_EN BIT(11)
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#define PCIEX8MGMT_PHY_INIT_VAL (PCIEX8MGMT_PHY_CDR_TRACK_EN|\
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PCIEX8MGMT_PHY_LOS_THRSHLD|\
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PCIEX8MGMT_PHY_TERM_EN|\
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PCIEX8MGMT_PHY_TERM_ACDC|\
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PCIEX8MGMT_PHY_EN)
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#define PCIEX8MGMT_PHY_LANEN_DIG_ASIC_RX_OVRD_IN_3 0x1008
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#define PCIEX8MGMT_PHY_LANE_OFF 0x100
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#define PCIEX8MGMT_PHY_LANE0_BASE (PCIEX8MGMT_PHY_LANEN_DIG_ASIC_RX_OVRD_IN_3 + 0x100 * 0)
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#define PCIEX8MGMT_PHY_LANE1_BASE (PCIEX8MGMT_PHY_LANEN_DIG_ASIC_RX_OVRD_IN_3 + 0x100 * 1)
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#define PCIEX8MGMT_PHY_LANE2_BASE (PCIEX8MGMT_PHY_LANEN_DIG_ASIC_RX_OVRD_IN_3 + 0x100 * 2)
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#define PCIEX8MGMT_PHY_LANE3_BASE (PCIEX8MGMT_PHY_LANEN_DIG_ASIC_RX_OVRD_IN_3 + 0x100 * 3)
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static void fu740_pcie_assert_reset(struct fu740_pcie *afp)
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{
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/* Assert PERST_N GPIO */
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gpiod_set_value_cansleep(afp->reset, 0);
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/* Assert controller PERST_N */
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writel_relaxed(0x0, afp->mgmt_base + PCIEX8MGMT_PERST_N);
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}
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static void fu740_pcie_deassert_reset(struct fu740_pcie *afp)
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{
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/* Deassert controller PERST_N */
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writel_relaxed(0x1, afp->mgmt_base + PCIEX8MGMT_PERST_N);
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/* Deassert PERST_N GPIO */
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gpiod_set_value_cansleep(afp->reset, 1);
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}
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static void fu740_pcie_power_on(struct fu740_pcie *afp)
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{
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gpiod_set_value_cansleep(afp->pwren, 1);
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/*
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* Ensure that PERST has been asserted for at least 100 ms.
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* Section 2.2 of PCI Express Card Electromechanical Specification
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* Revision 3.0
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*/
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msleep(100);
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}
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static void fu740_pcie_drive_reset(struct fu740_pcie *afp)
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{
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fu740_pcie_assert_reset(afp);
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fu740_pcie_power_on(afp);
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fu740_pcie_deassert_reset(afp);
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}
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static void fu740_phyregwrite(const uint8_t phy, const uint16_t addr,
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const uint16_t wrdata, struct fu740_pcie *afp)
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{
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struct device *dev = afp->pci.dev;
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void __iomem *phy_cr_para_addr;
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void __iomem *phy_cr_para_wr_data;
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void __iomem *phy_cr_para_wr_en;
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void __iomem *phy_cr_para_ack;
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int ret, val;
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/* Setup */
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if (phy) {
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phy_cr_para_addr = afp->mgmt_base + PCIEX8MGMT_PHY1_CR_PARA_ADDR;
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phy_cr_para_wr_data = afp->mgmt_base + PCIEX8MGMT_PHY1_CR_PARA_WR_DATA;
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phy_cr_para_wr_en = afp->mgmt_base + PCIEX8MGMT_PHY1_CR_PARA_WR_EN;
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phy_cr_para_ack = afp->mgmt_base + PCIEX8MGMT_PHY1_CR_PARA_ACK;
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} else {
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phy_cr_para_addr = afp->mgmt_base + PCIEX8MGMT_PHY0_CR_PARA_ADDR;
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phy_cr_para_wr_data = afp->mgmt_base + PCIEX8MGMT_PHY0_CR_PARA_WR_DATA;
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phy_cr_para_wr_en = afp->mgmt_base + PCIEX8MGMT_PHY0_CR_PARA_WR_EN;
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phy_cr_para_ack = afp->mgmt_base + PCIEX8MGMT_PHY0_CR_PARA_ACK;
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}
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writel_relaxed(addr, phy_cr_para_addr);
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writel_relaxed(wrdata, phy_cr_para_wr_data);
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writel_relaxed(1, phy_cr_para_wr_en);
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/* Wait for wait_idle */
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ret = readl_poll_timeout(phy_cr_para_ack, val, val, 10, 5000);
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if (ret)
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dev_warn(dev, "Wait for wait_idle state failed!\n");
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/* Clear */
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writel_relaxed(0, phy_cr_para_wr_en);
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/* Wait for ~wait_idle */
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ret = readl_poll_timeout(phy_cr_para_ack, val, !val, 10, 5000);
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if (ret)
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dev_warn(dev, "Wait for !wait_idle state failed!\n");
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}
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static void fu740_pcie_init_phy(struct fu740_pcie *afp)
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{
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/* Enable phy cr_para_sel interfaces */
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writel_relaxed(0x1, afp->mgmt_base + PCIEX8MGMT_PHY0_CR_PARA_SEL);
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writel_relaxed(0x1, afp->mgmt_base + PCIEX8MGMT_PHY1_CR_PARA_SEL);
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/*
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* Wait 10 cr_para cycles to guarantee that the registers are ready
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* to be edited.
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*/
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ndelay(10);
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/* Set PHY AC termination mode */
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fu740_phyregwrite(0, PCIEX8MGMT_PHY_LANE0_BASE, PCIEX8MGMT_PHY_INIT_VAL, afp);
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fu740_phyregwrite(0, PCIEX8MGMT_PHY_LANE1_BASE, PCIEX8MGMT_PHY_INIT_VAL, afp);
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fu740_phyregwrite(0, PCIEX8MGMT_PHY_LANE2_BASE, PCIEX8MGMT_PHY_INIT_VAL, afp);
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fu740_phyregwrite(0, PCIEX8MGMT_PHY_LANE3_BASE, PCIEX8MGMT_PHY_INIT_VAL, afp);
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fu740_phyregwrite(1, PCIEX8MGMT_PHY_LANE0_BASE, PCIEX8MGMT_PHY_INIT_VAL, afp);
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fu740_phyregwrite(1, PCIEX8MGMT_PHY_LANE1_BASE, PCIEX8MGMT_PHY_INIT_VAL, afp);
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fu740_phyregwrite(1, PCIEX8MGMT_PHY_LANE2_BASE, PCIEX8MGMT_PHY_INIT_VAL, afp);
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fu740_phyregwrite(1, PCIEX8MGMT_PHY_LANE3_BASE, PCIEX8MGMT_PHY_INIT_VAL, afp);
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}
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static int fu740_pcie_start_link(struct dw_pcie *pci)
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{
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struct device *dev = pci->dev;
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struct fu740_pcie *afp = dev_get_drvdata(dev);
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u8 cap_exp = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
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int ret;
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u32 orig, tmp;
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/*
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* Force 2.5GT/s when starting the link, due to some devices not
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* probing at higher speeds. This happens with the PCIe switch
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* on the Unmatched board when U-Boot has not initialised the PCIe.
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* The fix in U-Boot is to force 2.5GT/s, which then gets cleared
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* by the soft reset done by this driver.
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*/
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dev_dbg(dev, "cap_exp at %x\n", cap_exp);
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dw_pcie_dbi_ro_wr_en(pci);
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tmp = dw_pcie_readl_dbi(pci, cap_exp + PCI_EXP_LNKCAP);
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orig = tmp & PCI_EXP_LNKCAP_SLS;
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tmp &= ~PCI_EXP_LNKCAP_SLS;
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tmp |= PCI_EXP_LNKCAP_SLS_2_5GB;
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dw_pcie_writel_dbi(pci, cap_exp + PCI_EXP_LNKCAP, tmp);
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/* Enable LTSSM */
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writel_relaxed(0x1, afp->mgmt_base + PCIEX8MGMT_APP_LTSSM_ENABLE);
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ret = dw_pcie_wait_for_link(pci);
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if (ret) {
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dev_err(dev, "error: link did not start\n");
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goto err;
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}
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tmp = dw_pcie_readl_dbi(pci, cap_exp + PCI_EXP_LNKCAP);
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if ((tmp & PCI_EXP_LNKCAP_SLS) != orig) {
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dev_dbg(dev, "changing speed back to original\n");
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tmp &= ~PCI_EXP_LNKCAP_SLS;
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tmp |= orig;
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dw_pcie_writel_dbi(pci, cap_exp + PCI_EXP_LNKCAP, tmp);
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tmp = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
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tmp |= PORT_LOGIC_SPEED_CHANGE;
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dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, tmp);
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ret = dw_pcie_wait_for_link(pci);
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if (ret) {
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dev_err(dev, "error: link did not start at new speed\n");
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goto err;
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}
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}
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ret = 0;
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err:
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WARN_ON(ret); /* we assume that errors will be very rare */
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dw_pcie_dbi_ro_wr_dis(pci);
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return ret;
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}
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static int fu740_pcie_host_init(struct pcie_port *pp)
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{
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struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
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struct fu740_pcie *afp = to_fu740_pcie(pci);
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struct device *dev = pci->dev;
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int ret;
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/* Power on reset */
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fu740_pcie_drive_reset(afp);
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/* Enable pcieauxclk */
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ret = clk_prepare_enable(afp->pcie_aux);
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if (ret) {
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dev_err(dev, "unable to enable pcie_aux clock\n");
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return ret;
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}
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/*
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* Assert hold_phy_rst (hold the controller LTSSM in reset after
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* power_up_rst_n for register programming with cr_para)
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*/
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writel_relaxed(0x1, afp->mgmt_base + PCIEX8MGMT_APP_HOLD_PHY_RST);
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/* Deassert power_up_rst_n */
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ret = reset_control_deassert(afp->rst);
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if (ret) {
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dev_err(dev, "unable to deassert pcie_power_up_rst_n\n");
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return ret;
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}
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fu740_pcie_init_phy(afp);
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/* Disable pcieauxclk */
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clk_disable_unprepare(afp->pcie_aux);
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/* Clear hold_phy_rst */
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writel_relaxed(0x0, afp->mgmt_base + PCIEX8MGMT_APP_HOLD_PHY_RST);
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/* Enable pcieauxclk */
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clk_prepare_enable(afp->pcie_aux);
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/* Set RC mode */
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writel_relaxed(0x4, afp->mgmt_base + PCIEX8MGMT_DEVICE_TYPE);
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return 0;
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}
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static const struct dw_pcie_host_ops fu740_pcie_host_ops = {
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.host_init = fu740_pcie_host_init,
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};
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static const struct dw_pcie_ops dw_pcie_ops = {
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.start_link = fu740_pcie_start_link,
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};
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static int fu740_pcie_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct dw_pcie *pci;
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struct fu740_pcie *afp;
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afp = devm_kzalloc(dev, sizeof(*afp), GFP_KERNEL);
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if (!afp)
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return -ENOMEM;
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pci = &afp->pci;
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pci->dev = dev;
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pci->ops = &dw_pcie_ops;
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pci->pp.ops = &fu740_pcie_host_ops;
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/* SiFive specific region: mgmt */
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afp->mgmt_base = devm_platform_ioremap_resource_byname(pdev, "mgmt");
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if (IS_ERR(afp->mgmt_base))
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return PTR_ERR(afp->mgmt_base);
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/* Fetch GPIOs */
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afp->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
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if (IS_ERR(afp->reset))
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return dev_err_probe(dev, PTR_ERR(afp->reset), "unable to get reset-gpios\n");
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afp->pwren = devm_gpiod_get_optional(dev, "pwren", GPIOD_OUT_LOW);
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if (IS_ERR(afp->pwren))
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return dev_err_probe(dev, PTR_ERR(afp->pwren), "unable to get pwren-gpios\n");
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/* Fetch clocks */
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afp->pcie_aux = devm_clk_get(dev, "pcie_aux");
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if (IS_ERR(afp->pcie_aux))
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return dev_err_probe(dev, PTR_ERR(afp->pcie_aux),
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"pcie_aux clock source missing or invalid\n");
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/* Fetch reset */
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afp->rst = devm_reset_control_get_exclusive(dev, NULL);
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if (IS_ERR(afp->rst))
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return dev_err_probe(dev, PTR_ERR(afp->rst), "unable to get reset\n");
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platform_set_drvdata(pdev, afp);
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return dw_pcie_host_init(&pci->pp);
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}
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static void fu740_pcie_shutdown(struct platform_device *pdev)
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{
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struct fu740_pcie *afp = platform_get_drvdata(pdev);
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/* Bring down link, so bootloader gets clean state in case of reboot */
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fu740_pcie_assert_reset(afp);
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}
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static const struct of_device_id fu740_pcie_of_match[] = {
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{ .compatible = "sifive,fu740-pcie", },
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{},
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};
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static struct platform_driver fu740_pcie_driver = {
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.driver = {
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.name = "fu740-pcie",
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.of_match_table = fu740_pcie_of_match,
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.suppress_bind_attrs = true,
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},
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.probe = fu740_pcie_probe,
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.shutdown = fu740_pcie_shutdown,
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};
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builtin_platform_driver(fu740_pcie_driver);
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