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linux/drivers/pci/dwc/pci-imx6.c
Andrey Smirnov e6dcd87fff PCI: imx6: Do not wait for speed change on i.MX7 
As can be seen from [1]:

  "...the different behavior between iMX6Q PCIe and iMX7D PCIe maybe caused
  by the different controller version.

  Regarding to the DOC description, the DIRECT_SPEED_CHANGE should be
  cleared after the speed change from GEN1 to GEN2. Unfortunately, when
  GEN1 device is used, the behavior is not documented.

  So, IC design guys run the simulation and find out the following
  behaviors:

     1. DIRECT_SPEED_CHANGE will be cleared in 7D after speed change
     	from GEN1 to GEN2. This matches doc’s description

     2. set MAX link speed(PCIE_CAP_TARGET_LINK_SPEED=0x01) as GEN1 and
     	re-run the simulation, DIRECT_SPEED_CHANGE will not be cleared;
     	remain as 1, this matches your result, but function test is
     	passed, so this bit should not affect the normal PCIe function."

imx6_pcie_wait_for_speed_change() will report false failures for Gen1 ->
Gen1 speed transition, so avoid doing that check and just rely on
imx6_pcie_wait_for_link() only.

[1] https://community.nxp.com/message/867943

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Cc: yurovsky@gmail.com
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Dong Aisheng <dongas86@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
2017-04-04 17:56:41 -05:00

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/*
* PCIe host controller driver for Freescale i.MX6 SoCs
*
* Copyright (C) 2013 Kosagi
* http://www.kosagi.com
*
* Author: Sean Cross <xobs@kosagi.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
#include <linux/mfd/syscon/imx7-iomuxc-gpr.h>
#include <linux/module.h>
#include <linux/of_gpio.h>
#include <linux/of_device.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/resource.h>
#include <linux/signal.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/reset.h>
#include "pcie-designware.h"
#define to_imx6_pcie(x) dev_get_drvdata((x)->dev)
enum imx6_pcie_variants {
IMX6Q,
IMX6SX,
IMX6QP,
IMX7D,
};
struct imx6_pcie {
struct dw_pcie *pci;
int reset_gpio;
bool gpio_active_high;
struct clk *pcie_bus;
struct clk *pcie_phy;
struct clk *pcie_inbound_axi;
struct clk *pcie;
struct regmap *iomuxc_gpr;
struct reset_control *pciephy_reset;
struct reset_control *apps_reset;
enum imx6_pcie_variants variant;
u32 tx_deemph_gen1;
u32 tx_deemph_gen2_3p5db;
u32 tx_deemph_gen2_6db;
u32 tx_swing_full;
u32 tx_swing_low;
int link_gen;
};
/* Parameters for the waiting for PCIe PHY PLL to lock on i.MX7 */
#define PHY_PLL_LOCK_WAIT_MAX_RETRIES 2000
#define PHY_PLL_LOCK_WAIT_USLEEP_MIN 50
#define PHY_PLL_LOCK_WAIT_USLEEP_MAX 200
/* PCIe Root Complex registers (memory-mapped) */
#define PCIE_RC_LCR 0x7c
#define PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN1 0x1
#define PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN2 0x2
#define PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK 0xf
#define PCIE_RC_LCSR 0x80
/* PCIe Port Logic registers (memory-mapped) */
#define PL_OFFSET 0x700
#define PCIE_PL_PFLR (PL_OFFSET + 0x08)
#define PCIE_PL_PFLR_LINK_STATE_MASK (0x3f << 16)
#define PCIE_PL_PFLR_FORCE_LINK (1 << 15)
#define PCIE_PHY_DEBUG_R0 (PL_OFFSET + 0x28)
#define PCIE_PHY_DEBUG_R1 (PL_OFFSET + 0x2c)
#define PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING (1 << 29)
#define PCIE_PHY_DEBUG_R1_XMLH_LINK_UP (1 << 4)
#define PCIE_PHY_CTRL (PL_OFFSET + 0x114)
#define PCIE_PHY_CTRL_DATA_LOC 0
#define PCIE_PHY_CTRL_CAP_ADR_LOC 16
#define PCIE_PHY_CTRL_CAP_DAT_LOC 17
#define PCIE_PHY_CTRL_WR_LOC 18
#define PCIE_PHY_CTRL_RD_LOC 19
#define PCIE_PHY_STAT (PL_OFFSET + 0x110)
#define PCIE_PHY_STAT_ACK_LOC 16
#define PCIE_LINK_WIDTH_SPEED_CONTROL 0x80C
#define PORT_LOGIC_SPEED_CHANGE (0x1 << 17)
/* PHY registers (not memory-mapped) */
#define PCIE_PHY_RX_ASIC_OUT 0x100D
#define PCIE_PHY_RX_ASIC_OUT_VALID (1 << 0)
#define PHY_RX_OVRD_IN_LO 0x1005
#define PHY_RX_OVRD_IN_LO_RX_DATA_EN (1 << 5)
#define PHY_RX_OVRD_IN_LO_RX_PLL_EN (1 << 3)
static int pcie_phy_poll_ack(struct imx6_pcie *imx6_pcie, int exp_val)
{
struct dw_pcie *pci = imx6_pcie->pci;
u32 val;
u32 max_iterations = 10;
u32 wait_counter = 0;
do {
val = dw_pcie_readl_dbi(pci, PCIE_PHY_STAT);
val = (val >> PCIE_PHY_STAT_ACK_LOC) & 0x1;
wait_counter++;
if (val == exp_val)
return 0;
udelay(1);
} while (wait_counter < max_iterations);
return -ETIMEDOUT;
}
static int pcie_phy_wait_ack(struct imx6_pcie *imx6_pcie, int addr)
{
struct dw_pcie *pci = imx6_pcie->pci;
u32 val;
int ret;
val = addr << PCIE_PHY_CTRL_DATA_LOC;
dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, val);
val |= (0x1 << PCIE_PHY_CTRL_CAP_ADR_LOC);
dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, val);
ret = pcie_phy_poll_ack(imx6_pcie, 1);
if (ret)
return ret;
val = addr << PCIE_PHY_CTRL_DATA_LOC;
dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, val);
return pcie_phy_poll_ack(imx6_pcie, 0);
}
/* Read from the 16-bit PCIe PHY control registers (not memory-mapped) */
static int pcie_phy_read(struct imx6_pcie *imx6_pcie, int addr, int *data)
{
struct dw_pcie *pci = imx6_pcie->pci;
u32 val, phy_ctl;
int ret;
ret = pcie_phy_wait_ack(imx6_pcie, addr);
if (ret)
return ret;
/* assert Read signal */
phy_ctl = 0x1 << PCIE_PHY_CTRL_RD_LOC;
dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, phy_ctl);
ret = pcie_phy_poll_ack(imx6_pcie, 1);
if (ret)
return ret;
val = dw_pcie_readl_dbi(pci, PCIE_PHY_STAT);
*data = val & 0xffff;
/* deassert Read signal */
dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, 0x00);
return pcie_phy_poll_ack(imx6_pcie, 0);
}
static int pcie_phy_write(struct imx6_pcie *imx6_pcie, int addr, int data)
{
struct dw_pcie *pci = imx6_pcie->pci;
u32 var;
int ret;
/* write addr */
/* cap addr */
ret = pcie_phy_wait_ack(imx6_pcie, addr);
if (ret)
return ret;
var = data << PCIE_PHY_CTRL_DATA_LOC;
dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, var);
/* capture data */
var |= (0x1 << PCIE_PHY_CTRL_CAP_DAT_LOC);
dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, var);
ret = pcie_phy_poll_ack(imx6_pcie, 1);
if (ret)
return ret;
/* deassert cap data */
var = data << PCIE_PHY_CTRL_DATA_LOC;
dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, var);
/* wait for ack de-assertion */
ret = pcie_phy_poll_ack(imx6_pcie, 0);
if (ret)
return ret;
/* assert wr signal */
var = 0x1 << PCIE_PHY_CTRL_WR_LOC;
dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, var);
/* wait for ack */
ret = pcie_phy_poll_ack(imx6_pcie, 1);
if (ret)
return ret;
/* deassert wr signal */
var = data << PCIE_PHY_CTRL_DATA_LOC;
dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, var);
/* wait for ack de-assertion */
ret = pcie_phy_poll_ack(imx6_pcie, 0);
if (ret)
return ret;
dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, 0x0);
return 0;
}
static void imx6_pcie_reset_phy(struct imx6_pcie *imx6_pcie)
{
u32 tmp;
pcie_phy_read(imx6_pcie, PHY_RX_OVRD_IN_LO, &tmp);
tmp |= (PHY_RX_OVRD_IN_LO_RX_DATA_EN |
PHY_RX_OVRD_IN_LO_RX_PLL_EN);
pcie_phy_write(imx6_pcie, PHY_RX_OVRD_IN_LO, tmp);
usleep_range(2000, 3000);
pcie_phy_read(imx6_pcie, PHY_RX_OVRD_IN_LO, &tmp);
tmp &= ~(PHY_RX_OVRD_IN_LO_RX_DATA_EN |
PHY_RX_OVRD_IN_LO_RX_PLL_EN);
pcie_phy_write(imx6_pcie, PHY_RX_OVRD_IN_LO, tmp);
}
/* Added for PCI abort handling */
static int imx6q_pcie_abort_handler(unsigned long addr,
unsigned int fsr, struct pt_regs *regs)
{
return 0;
}
static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
{
switch (imx6_pcie->variant) {
case IMX7D:
reset_control_assert(imx6_pcie->pciephy_reset);
reset_control_assert(imx6_pcie->apps_reset);
break;
case IMX6SX:
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
IMX6SX_GPR12_PCIE_TEST_POWERDOWN,
IMX6SX_GPR12_PCIE_TEST_POWERDOWN);
/* Force PCIe PHY reset */
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR5,
IMX6SX_GPR5_PCIE_BTNRST_RESET,
IMX6SX_GPR5_PCIE_BTNRST_RESET);
break;
case IMX6QP:
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
IMX6Q_GPR1_PCIE_SW_RST,
IMX6Q_GPR1_PCIE_SW_RST);
break;
case IMX6Q:
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
IMX6Q_GPR1_PCIE_TEST_PD, 1 << 18);
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16);
break;
}
}
static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
{
struct dw_pcie *pci = imx6_pcie->pci;
struct device *dev = pci->dev;
int ret = 0;
switch (imx6_pcie->variant) {
case IMX6SX:
ret = clk_prepare_enable(imx6_pcie->pcie_inbound_axi);
if (ret) {
dev_err(dev, "unable to enable pcie_axi clock\n");
break;
}
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
IMX6SX_GPR12_PCIE_TEST_POWERDOWN, 0);
break;
case IMX6QP: /* FALLTHROUGH */
case IMX6Q:
/* power up core phy and enable ref clock */
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18);
/*
* the async reset input need ref clock to sync internally,
* when the ref clock comes after reset, internal synced
* reset time is too short, cannot meet the requirement.
* add one ~10us delay here.
*/
udelay(10);
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16);
break;
case IMX7D:
break;
}
return ret;
}
static void imx7d_pcie_wait_for_phy_pll_lock(struct imx6_pcie *imx6_pcie)
{
u32 val;
unsigned int retries;
struct device *dev = imx6_pcie->pci->dev;
for (retries = 0; retries < PHY_PLL_LOCK_WAIT_MAX_RETRIES; retries++) {
regmap_read(imx6_pcie->iomuxc_gpr, IOMUXC_GPR22, &val);
if (val & IMX7D_GPR22_PCIE_PHY_PLL_LOCKED)
return;
usleep_range(PHY_PLL_LOCK_WAIT_USLEEP_MIN,
PHY_PLL_LOCK_WAIT_USLEEP_MAX);
}
dev_err(dev, "PCIe PLL lock timeout\n");
}
static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
{
struct dw_pcie *pci = imx6_pcie->pci;
struct device *dev = pci->dev;
int ret;
ret = clk_prepare_enable(imx6_pcie->pcie_phy);
if (ret) {
dev_err(dev, "unable to enable pcie_phy clock\n");
return;
}
ret = clk_prepare_enable(imx6_pcie->pcie_bus);
if (ret) {
dev_err(dev, "unable to enable pcie_bus clock\n");
goto err_pcie_bus;
}
ret = clk_prepare_enable(imx6_pcie->pcie);
if (ret) {
dev_err(dev, "unable to enable pcie clock\n");
goto err_pcie;
}
ret = imx6_pcie_enable_ref_clk(imx6_pcie);
if (ret) {
dev_err(dev, "unable to enable pcie ref clock\n");
goto err_ref_clk;
}
/* allow the clocks to stabilize */
usleep_range(200, 500);
/* Some boards don't have PCIe reset GPIO. */
if (gpio_is_valid(imx6_pcie->reset_gpio)) {
gpio_set_value_cansleep(imx6_pcie->reset_gpio,
imx6_pcie->gpio_active_high);
msleep(100);
gpio_set_value_cansleep(imx6_pcie->reset_gpio,
!imx6_pcie->gpio_active_high);
}
switch (imx6_pcie->variant) {
case IMX7D:
reset_control_deassert(imx6_pcie->pciephy_reset);
imx7d_pcie_wait_for_phy_pll_lock(imx6_pcie);
break;
case IMX6SX:
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR5,
IMX6SX_GPR5_PCIE_BTNRST_RESET, 0);
break;
case IMX6QP:
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
IMX6Q_GPR1_PCIE_SW_RST, 0);
usleep_range(200, 500);
break;
case IMX6Q: /* Nothing to do */
break;
}
return;
err_ref_clk:
clk_disable_unprepare(imx6_pcie->pcie);
err_pcie:
clk_disable_unprepare(imx6_pcie->pcie_bus);
err_pcie_bus:
clk_disable_unprepare(imx6_pcie->pcie_phy);
}
static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
{
switch (imx6_pcie->variant) {
case IMX7D:
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
IMX7D_GPR12_PCIE_PHY_REFCLK_SEL, 0);
break;
case IMX6SX:
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
IMX6SX_GPR12_PCIE_RX_EQ_MASK,
IMX6SX_GPR12_PCIE_RX_EQ_2);
/* FALLTHROUGH */
default:
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
IMX6Q_GPR12_PCIE_CTL_2, 0 << 10);
/* configure constant input signal to the pcie ctrl and phy */
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
IMX6Q_GPR12_LOS_LEVEL, 9 << 4);
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
IMX6Q_GPR8_TX_DEEMPH_GEN1,
imx6_pcie->tx_deemph_gen1 << 0);
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
IMX6Q_GPR8_TX_DEEMPH_GEN2_3P5DB,
imx6_pcie->tx_deemph_gen2_3p5db << 6);
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
IMX6Q_GPR8_TX_DEEMPH_GEN2_6DB,
imx6_pcie->tx_deemph_gen2_6db << 12);
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
IMX6Q_GPR8_TX_SWING_FULL,
imx6_pcie->tx_swing_full << 18);
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
IMX6Q_GPR8_TX_SWING_LOW,
imx6_pcie->tx_swing_low << 25);
break;
}
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
IMX6Q_GPR12_DEVICE_TYPE, PCI_EXP_TYPE_ROOT_PORT << 12);
}
static int imx6_pcie_wait_for_link(struct imx6_pcie *imx6_pcie)
{
struct dw_pcie *pci = imx6_pcie->pci;
struct device *dev = pci->dev;
/* check if the link is up or not */
if (!dw_pcie_wait_for_link(pci))
return 0;
dev_dbg(dev, "DEBUG_R0: 0x%08x, DEBUG_R1: 0x%08x\n",
dw_pcie_readl_dbi(pci, PCIE_PHY_DEBUG_R0),
dw_pcie_readl_dbi(pci, PCIE_PHY_DEBUG_R1));
return -ETIMEDOUT;
}
static int imx6_pcie_wait_for_speed_change(struct imx6_pcie *imx6_pcie)
{
struct dw_pcie *pci = imx6_pcie->pci;
struct device *dev = pci->dev;
u32 tmp;
unsigned int retries;
for (retries = 0; retries < 200; retries++) {
tmp = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
/* Test if the speed change finished. */
if (!(tmp & PORT_LOGIC_SPEED_CHANGE))
return 0;
usleep_range(100, 1000);
}
dev_err(dev, "Speed change timeout\n");
return -EINVAL;
}
static irqreturn_t imx6_pcie_msi_handler(int irq, void *arg)
{
struct imx6_pcie *imx6_pcie = arg;
struct dw_pcie *pci = imx6_pcie->pci;
struct pcie_port *pp = &pci->pp;
return dw_handle_msi_irq(pp);
}
static int imx6_pcie_establish_link(struct imx6_pcie *imx6_pcie)
{
struct dw_pcie *pci = imx6_pcie->pci;
struct device *dev = pci->dev;
u32 tmp;
int ret;
/*
* Force Gen1 operation when starting the link. In case the link is
* started in Gen2 mode, there is a possibility the devices on the
* bus will not be detected at all. This happens with PCIe switches.
*/
tmp = dw_pcie_readl_dbi(pci, PCIE_RC_LCR);
tmp &= ~PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK;
tmp |= PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN1;
dw_pcie_writel_dbi(pci, PCIE_RC_LCR, tmp);
/* Start LTSSM. */
if (imx6_pcie->variant == IMX7D)
reset_control_deassert(imx6_pcie->apps_reset);
else
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
IMX6Q_GPR12_PCIE_CTL_2, 1 << 10);
ret = imx6_pcie_wait_for_link(imx6_pcie);
if (ret)
goto err_reset_phy;
if (imx6_pcie->link_gen == 2) {
/* Allow Gen2 mode after the link is up. */
tmp = dw_pcie_readl_dbi(pci, PCIE_RC_LCR);
tmp &= ~PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK;
tmp |= PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN2;
dw_pcie_writel_dbi(pci, PCIE_RC_LCR, tmp);
} else {
dev_info(dev, "Link: Gen2 disabled\n");
}
/*
* Start Directed Speed Change so the best possible speed both link
* partners support can be negotiated.
*/
tmp = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
tmp |= PORT_LOGIC_SPEED_CHANGE;
dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, tmp);
if (imx6_pcie->variant != IMX7D) {
/*
* On i.MX7, DIRECT_SPEED_CHANGE behaves differently
* from i.MX6 family when no link speed transition
* occurs and we go Gen1 -> yep, Gen1. The difference
* is that, in such case, it will not be cleared by HW
* which will cause the following code to report false
* failure.
*/
ret = imx6_pcie_wait_for_speed_change(imx6_pcie);
if (ret) {
dev_err(dev, "Failed to bring link up!\n");
goto err_reset_phy;
}
}
/* Make sure link training is finished as well! */
ret = imx6_pcie_wait_for_link(imx6_pcie);
if (ret) {
dev_err(dev, "Failed to bring link up!\n");
goto err_reset_phy;
}
tmp = dw_pcie_readl_dbi(pci, PCIE_RC_LCSR);
dev_info(dev, "Link up, Gen%i\n", (tmp >> 16) & 0xf);
return 0;
err_reset_phy:
dev_dbg(dev, "PHY DEBUG_R0=0x%08x DEBUG_R1=0x%08x\n",
dw_pcie_readl_dbi(pci, PCIE_PHY_DEBUG_R0),
dw_pcie_readl_dbi(pci, PCIE_PHY_DEBUG_R1));
imx6_pcie_reset_phy(imx6_pcie);
return ret;
}
static void imx6_pcie_host_init(struct pcie_port *pp)
{
struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
struct imx6_pcie *imx6_pcie = to_imx6_pcie(pci);
imx6_pcie_assert_core_reset(imx6_pcie);
imx6_pcie_init_phy(imx6_pcie);
imx6_pcie_deassert_core_reset(imx6_pcie);
dw_pcie_setup_rc(pp);
imx6_pcie_establish_link(imx6_pcie);
if (IS_ENABLED(CONFIG_PCI_MSI))
dw_pcie_msi_init(pp);
}
static int imx6_pcie_link_up(struct dw_pcie *pci)
{
return dw_pcie_readl_dbi(pci, PCIE_PHY_DEBUG_R1) &
PCIE_PHY_DEBUG_R1_XMLH_LINK_UP;
}
static struct dw_pcie_host_ops imx6_pcie_host_ops = {
.host_init = imx6_pcie_host_init,
};
static int imx6_add_pcie_port(struct imx6_pcie *imx6_pcie,
struct platform_device *pdev)
{
struct dw_pcie *pci = imx6_pcie->pci;
struct pcie_port *pp = &pci->pp;
struct device *dev = &pdev->dev;
int ret;
if (IS_ENABLED(CONFIG_PCI_MSI)) {
pp->msi_irq = platform_get_irq_byname(pdev, "msi");
if (pp->msi_irq <= 0) {
dev_err(dev, "failed to get MSI irq\n");
return -ENODEV;
}
ret = devm_request_irq(dev, pp->msi_irq,
imx6_pcie_msi_handler,
IRQF_SHARED | IRQF_NO_THREAD,
"mx6-pcie-msi", imx6_pcie);
if (ret) {
dev_err(dev, "failed to request MSI irq\n");
return ret;
}
}
pp->root_bus_nr = -1;
pp->ops = &imx6_pcie_host_ops;
ret = dw_pcie_host_init(pp);
if (ret) {
dev_err(dev, "failed to initialize host\n");
return ret;
}
return 0;
}
static const struct dw_pcie_ops dw_pcie_ops = {
.link_up = imx6_pcie_link_up,
};
static int imx6_pcie_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct dw_pcie *pci;
struct imx6_pcie *imx6_pcie;
struct resource *dbi_base;
struct device_node *node = dev->of_node;
int ret;
imx6_pcie = devm_kzalloc(dev, sizeof(*imx6_pcie), GFP_KERNEL);
if (!imx6_pcie)
return -ENOMEM;
pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
if (!pci)
return -ENOMEM;
pci->dev = dev;
pci->ops = &dw_pcie_ops;
imx6_pcie->pci = pci;
imx6_pcie->variant =
(enum imx6_pcie_variants)of_device_get_match_data(dev);
dbi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
pci->dbi_base = devm_ioremap_resource(dev, dbi_base);
if (IS_ERR(pci->dbi_base))
return PTR_ERR(pci->dbi_base);
/* Fetch GPIOs */
imx6_pcie->reset_gpio = of_get_named_gpio(node, "reset-gpio", 0);
imx6_pcie->gpio_active_high = of_property_read_bool(node,
"reset-gpio-active-high");
if (gpio_is_valid(imx6_pcie->reset_gpio)) {
ret = devm_gpio_request_one(dev, imx6_pcie->reset_gpio,
imx6_pcie->gpio_active_high ?
GPIOF_OUT_INIT_HIGH :
GPIOF_OUT_INIT_LOW,
"PCIe reset");
if (ret) {
dev_err(dev, "unable to get reset gpio\n");
return ret;
}
} else if (imx6_pcie->reset_gpio == -EPROBE_DEFER) {
return imx6_pcie->reset_gpio;
}
/* Fetch clocks */
imx6_pcie->pcie_phy = devm_clk_get(dev, "pcie_phy");
if (IS_ERR(imx6_pcie->pcie_phy)) {
dev_err(dev, "pcie_phy clock source missing or invalid\n");
return PTR_ERR(imx6_pcie->pcie_phy);
}
imx6_pcie->pcie_bus = devm_clk_get(dev, "pcie_bus");
if (IS_ERR(imx6_pcie->pcie_bus)) {
dev_err(dev, "pcie_bus clock source missing or invalid\n");
return PTR_ERR(imx6_pcie->pcie_bus);
}
imx6_pcie->pcie = devm_clk_get(dev, "pcie");
if (IS_ERR(imx6_pcie->pcie)) {
dev_err(dev, "pcie clock source missing or invalid\n");
return PTR_ERR(imx6_pcie->pcie);
}
switch (imx6_pcie->variant) {
case IMX6SX:
imx6_pcie->pcie_inbound_axi = devm_clk_get(dev,
"pcie_inbound_axi");
if (IS_ERR(imx6_pcie->pcie_inbound_axi)) {
dev_err(dev, "pcie_inbound_axi clock missing or invalid\n");
return PTR_ERR(imx6_pcie->pcie_inbound_axi);
}
break;
case IMX7D:
imx6_pcie->pciephy_reset = devm_reset_control_get(dev,
"pciephy");
if (IS_ERR(imx6_pcie->pciephy_reset)) {
dev_err(dev, "Failed to get PCIEPHY reset contol\n");
return PTR_ERR(imx6_pcie->pciephy_reset);
}
imx6_pcie->apps_reset = devm_reset_control_get(dev, "apps");
if (IS_ERR(imx6_pcie->apps_reset)) {
dev_err(dev, "Failed to get PCIE APPS reset contol\n");
return PTR_ERR(imx6_pcie->apps_reset);
}
break;
default:
break;
}
/* Grab GPR config register range */
imx6_pcie->iomuxc_gpr =
syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr");
if (IS_ERR(imx6_pcie->iomuxc_gpr)) {
dev_err(dev, "unable to find iomuxc registers\n");
return PTR_ERR(imx6_pcie->iomuxc_gpr);
}
/* Grab PCIe PHY Tx Settings */
if (of_property_read_u32(node, "fsl,tx-deemph-gen1",
&imx6_pcie->tx_deemph_gen1))
imx6_pcie->tx_deemph_gen1 = 0;
if (of_property_read_u32(node, "fsl,tx-deemph-gen2-3p5db",
&imx6_pcie->tx_deemph_gen2_3p5db))
imx6_pcie->tx_deemph_gen2_3p5db = 0;
if (of_property_read_u32(node, "fsl,tx-deemph-gen2-6db",
&imx6_pcie->tx_deemph_gen2_6db))
imx6_pcie->tx_deemph_gen2_6db = 20;
if (of_property_read_u32(node, "fsl,tx-swing-full",
&imx6_pcie->tx_swing_full))
imx6_pcie->tx_swing_full = 127;
if (of_property_read_u32(node, "fsl,tx-swing-low",
&imx6_pcie->tx_swing_low))
imx6_pcie->tx_swing_low = 127;
/* Limit link speed */
ret = of_property_read_u32(node, "fsl,max-link-speed",
&imx6_pcie->link_gen);
if (ret)
imx6_pcie->link_gen = 1;
platform_set_drvdata(pdev, imx6_pcie);
ret = imx6_add_pcie_port(imx6_pcie, pdev);
if (ret < 0)
return ret;
return 0;
}
static void imx6_pcie_shutdown(struct platform_device *pdev)
{
struct imx6_pcie *imx6_pcie = platform_get_drvdata(pdev);
/* bring down link, so bootloader gets clean state in case of reboot */
imx6_pcie_assert_core_reset(imx6_pcie);
}
static const struct of_device_id imx6_pcie_of_match[] = {
{ .compatible = "fsl,imx6q-pcie", .data = (void *)IMX6Q, },
{ .compatible = "fsl,imx6sx-pcie", .data = (void *)IMX6SX, },
{ .compatible = "fsl,imx6qp-pcie", .data = (void *)IMX6QP, },
{ .compatible = "fsl,imx7d-pcie", .data = (void *)IMX7D, },
{},
};
static struct platform_driver imx6_pcie_driver = {
.driver = {
.name = "imx6q-pcie",
.of_match_table = imx6_pcie_of_match,
},
.probe = imx6_pcie_probe,
.shutdown = imx6_pcie_shutdown,
};
static int __init imx6_pcie_init(void)
{
/*
* Since probe() can be deferred we need to make sure that
* hook_fault_code is not called after __init memory is freed
* by kernel and since imx6q_pcie_abort_handler() is a no-op,
* we can install the handler here without risking it
* accessing some uninitialized driver state.
*/
hook_fault_code(16 + 6, imx6q_pcie_abort_handler, SIGBUS, 0,
"imprecise external abort");
return platform_driver_register(&imx6_pcie_driver);
}
device_initcall(imx6_pcie_init);
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