// SPDX-License-Identifier: GPL-2.0
/*
* PCIe host controller driver for Amlogic MESON SoCs
*
* Copyright (c) 2018 Amlogic, inc.
* Author: Yue Wang <yue.wang@amlogic.com>
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/reset.h>
#include <linux/resource.h>
#include <linux/types.h>
#include <linux/phy/phy.h>
#include <linux/module.h>
#include "pcie-designware.h"
#define to_meson_pcie(x) dev_get_drvdata((x)->dev)
#define PCIE_CAP_MAX_PAYLOAD_SIZE(x) ((x) << 5)
#define PCIE_CAP_MAX_READ_REQ_SIZE(x) ((x) << 12)
/* PCIe specific config registers */
#define PCIE_CFG0 0x0
#define APP_LTSSM_ENABLE BIT(7)
#define PCIE_CFG_STATUS12 0x30
#define IS_SMLH_LINK_UP(x) ((x) & (1 << 6))
#define IS_RDLH_LINK_UP(x) ((x) & (1 << 16))
#define IS_LTSSM_UP(x) ((((x) >> 10) & 0x1f) == 0x11)
#define PCIE_CFG_STATUS17 0x44
#define PM_CURRENT_STATE(x) (((x) >> 7) & 0x1)
#define WAIT_LINKUP_TIMEOUT 4000
#define PORT_CLK_RATE 100000000UL
#define MAX_PAYLOAD_SIZE 256
#define MAX_READ_REQ_SIZE 256
#define PCIE_RESET_DELAY 500
#define PCIE_SHARED_RESET 1
#define PCIE_NORMAL_RESET 0
enum pcie_data_rate {
PCIE_GEN1,
PCIE_GEN2,
PCIE_GEN3,
PCIE_GEN4
};
struct meson_pcie_clk_res {
struct clk *clk;
struct clk *port_clk;
struct clk *general_clk;
};
struct meson_pcie_rc_reset {
struct reset_control *port;
struct reset_control *apb;
};
struct meson_pcie {
struct dw_pcie pci;
void __iomem *cfg_base;
struct meson_pcie_clk_res clk_res;
struct meson_pcie_rc_reset mrst;
struct gpio_desc *reset_gpio;
struct phy *phy;
};
static struct reset_control *meson_pcie_get_reset(struct meson_pcie *mp,
const char *id,
u32 reset_type)
{
struct device *dev = mp->pci.dev;
struct reset_control *reset;
if (reset_type == PCIE_SHARED_RESET)
reset = devm_reset_control_get_shared(dev, id);
else
reset = devm_reset_control_get(dev, id);
return reset;
}
static int meson_pcie_get_resets(struct meson_pcie *mp)
{
struct meson_pcie_rc_reset *mrst = &mp->mrst;
mrst->port = meson_pcie_get_reset(mp, "port", PCIE_NORMAL_RESET);
if (IS_ERR(mrst->port))
return PTR_ERR(mrst->port);
reset_control_deassert(mrst->port);
mrst->apb = meson_pcie_get_reset(mp, "apb", PCIE_SHARED_RESET);
if (IS_ERR(mrst->apb))
return PTR_ERR(mrst->apb);
reset_control_deassert(mrst->apb);
return 0;
}
static int meson_pcie_get_mems(struct platform_device *pdev,
struct meson_pcie *mp)
{
struct dw_pcie *pci = &mp->pci;
pci->dbi_base = devm_platform_ioremap_resource_byname(pdev, "elbi");
if (IS_ERR(pci->dbi_base))
return PTR_ERR(pci->dbi_base);
mp->cfg_base = devm_platform_ioremap_resource_byname(pdev, "cfg");
if (IS_ERR(mp->cfg_base))
return PTR_ERR(mp->cfg_base);
return 0;
}
static int meson_pcie_power_on(struct meson_pcie *mp)
{
int ret = 0;
ret = phy_init(mp->phy);
if (ret)
return ret;
ret = phy_power_on(mp->phy);
if (ret) {
phy_exit(mp->phy);
return ret;
}
return 0;
}
static void meson_pcie_power_off(struct meson_pcie *mp)
{
phy_power_off(mp->phy);
phy_exit(mp->phy);
}
static int meson_pcie_reset(struct meson_pcie *mp)
{
struct meson_pcie_rc_reset *mrst = &mp->mrst;
int ret = 0;
ret = phy_reset(mp->phy);
if (ret)
return ret;
reset_control_assert(mrst->port);
reset_control_assert(mrst->apb);
udelay(PCIE_RESET_DELAY);
reset_control_deassert(mrst->port);
reset_control_deassert(mrst->apb);
udelay(PCIE_RESET_DELAY);
return 0;
}
static inline struct clk *meson_pcie_probe_clock(struct device *dev,
const char *id, u64 rate)
{
struct clk *clk;
int ret;
clk = devm_clk_get(dev, id);
if (IS_ERR(clk))
return clk;
if (rate) {
ret = clk_set_rate(clk, rate);
if (ret) {
dev_err(dev, "set clk rate failed, ret = %d\n", ret);
return ERR_PTR(ret);
}
}
ret = clk_prepare_enable(clk);
if (ret) {
dev_err(dev, "couldn't enable clk\n");
return ERR_PTR(ret);
}
devm_add_action_or_reset(dev,
(void (*) (void *))clk_disable_unprepare,
clk);
return clk;
}
static int meson_pcie_probe_clocks(struct meson_pcie *mp)
{
struct device *dev = mp->pci.dev;
struct meson_pcie_clk_res *res = &mp->clk_res;
res->port_clk = meson_pcie_probe_clock(dev, "port", PORT_CLK_RATE);
if (IS_ERR(res->port_clk))
return PTR_ERR(res->port_clk);
res->general_clk = meson_pcie_probe_clock(dev, "general", 0);
if (IS_ERR(res->general_clk))
return PTR_ERR(res->general_clk);
res->clk = meson_pcie_probe_clock(dev, "pclk", 0);
if (IS_ERR(res->clk))
return PTR_ERR(res->clk);
return 0;
}
static inline u32 meson_cfg_readl(struct meson_pcie *mp, u32 reg)
{
return readl(mp->cfg_base + reg);
}
static inline void meson_cfg_writel(struct meson_pcie *mp, u32 val, u32 reg)
{
writel(val, mp->cfg_base + reg);
}
static void meson_pcie_assert_reset(struct meson_pcie *mp)
{
gpiod_set_value_cansleep(mp->reset_gpio, 1);
udelay(500);
gpiod_set_value_cansleep(mp->reset_gpio, 0);
}
static void meson_pcie_ltssm_enable(struct meson_pcie *mp)
{
u32 val;
val = meson_cfg_readl(mp, PCIE_CFG0);
val |= APP_LTSSM_ENABLE;
meson_cfg_writel(mp, val, PCIE_CFG0);
}
static int meson_size_to_payload(struct meson_pcie *mp, int size)
{
struct device *dev = mp->pci.dev;
/*
* dwc supports 2^(val+7) payload size, which val is 0~5 default to 1.
* So if input size is not 2^order alignment or less than 2^7 or bigger
* than 2^12, just set to default size 2^(1+7).
*/
if (!is_power_of_2(size) || size < 128 || size > 4096) {
dev_warn(dev, "payload size %d, set to default 256\n", size);
return 1;
}
return fls(size) - 8;
}
static void meson_set_max_payload(struct meson_pcie *mp, int size)
{
struct dw_pcie *pci = &mp->pci;
u32 val;
u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
int max_payload_size = meson_size_to_payload(mp, size);
val = dw_pcie_readl_dbi(pci, offset + PCI_EXP_DEVCTL);
val &= ~PCI_EXP_DEVCTL_PAYLOAD;
dw_pcie_writel_dbi(pci, offset + PCI_EXP_DEVCTL, val);
val = dw_pcie_readl_dbi(pci, offset + PCI_EXP_DEVCTL);
val |= PCIE_CAP_MAX_PAYLOAD_SIZE(max_payload_size);
dw_pcie_writel_dbi(pci, offset + PCI_EXP_DEVCTL, val);
}
static void meson_set_max_rd_req_size(struct meson_pcie *mp, int size)
{
struct dw_pcie *pci = &mp->pci;
u32 val;
u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
int max_rd_req_size = meson_size_to_payload(mp, size);
val = dw_pcie_readl_dbi(pci, offset + PCI_EXP_DEVCTL);
val &= ~PCI_EXP_DEVCTL_READRQ;
dw_pcie_writel_dbi(pci, offset + PCI_EXP_DEVCTL, val);
val = dw_pcie_readl_dbi(pci, offset + PCI_EXP_DEVCTL);
val |= PCIE_CAP_MAX_READ_REQ_SIZE(max_rd_req_size);
dw_pcie_writel_dbi(pci, offset + PCI_EXP_DEVCTL, val);
}
static int meson_pcie_start_link(struct dw_pcie *pci)
{
struct meson_pcie *mp = to_meson_pcie(pci);
meson_pcie_ltssm_enable(mp);
meson_pcie_assert_reset(mp);
return 0;
}
static int meson_pcie_rd_own_conf(struct pci_bus *bus, u32 devfn,
int where, int size, u32 *val)
{
int ret;
ret = pci_generic_config_read(bus, devfn, where, size, val);
if (ret != PCIBIOS_SUCCESSFUL)
return ret;
/*
* There is a bug in the MESON AXG PCIe controller whereby software
* cannot program the PCI_CLASS_DEVICE register, so we must fabricate
* the return value in the config accessors.
*/
if ((where & ~3) == PCI_CLASS_REVISION) {
if (size <= 2)
*val = (*val & ((1 << (size * 8)) - 1)) << (8 * (where & 3));
*val &= ~0xffffff00;
*val |= PCI_CLASS_BRIDGE_PCI_NORMAL << 8;
if (size <= 2)
*val = (*val >> (8 * (where & 3))) & ((1 << (size * 8)) - 1);
}
return PCIBIOS_SUCCESSFUL;
}
static struct pci_ops meson_pci_ops = {
.map_bus = dw_pcie_own_conf_map_bus,
.read = meson_pcie_rd_own_conf,
.write = pci_generic_config_write,
};
static int meson_pcie_link_up(struct dw_pcie *pci)
{
struct meson_pcie *mp = to_meson_pcie(pci);
struct device *dev = pci->dev;
u32 speed_okay = 0;
u32 cnt = 0;
u32 state12, state17, smlh_up, ltssm_up, rdlh_up;
do {
state12 = meson_cfg_readl(mp, PCIE_CFG_STATUS12);
state17 = meson_cfg_readl(mp, PCIE_CFG_STATUS17);
smlh_up = IS_SMLH_LINK_UP(state12);
rdlh_up = IS_RDLH_LINK_UP(state12);
ltssm_up = IS_LTSSM_UP(state12);
if (PM_CURRENT_STATE(state17) < PCIE_GEN3)
speed_okay = 1;
if (smlh_up)
dev_dbg(dev, "smlh_link_up is on\n");
if (rdlh_up)
dev_dbg(dev, "rdlh_link_up is on\n");
if (ltssm_up)
dev_dbg(dev, "ltssm_up is on\n");
if (speed_okay)
dev_dbg(dev, "speed_okay\n");
if (smlh_up && rdlh_up && ltssm_up && speed_okay)
return 1;
cnt++;
udelay(10);
} while (cnt < WAIT_LINKUP_TIMEOUT);
dev_err(dev, "error: wait linkup timeout\n");
return 0;
}
static int meson_pcie_host_init(struct dw_pcie_rp *pp)
{
struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
struct meson_pcie *mp = to_meson_pcie(pci);
pp->bridge->ops = &meson_pci_ops;
meson_set_max_payload(mp, MAX_PAYLOAD_SIZE);
meson_set_max_rd_req_size(mp, MAX_READ_REQ_SIZE);
return 0;
}
static const struct dw_pcie_host_ops meson_pcie_host_ops = {
.host_init = meson_pcie_host_init,
};
static const struct dw_pcie_ops dw_pcie_ops = {
.link_up = meson_pcie_link_up,
.start_link = meson_pcie_start_link,
};
static int meson_pcie_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct dw_pcie *pci;
struct meson_pcie *mp;
int ret;
mp = devm_kzalloc(dev, sizeof(*mp), GFP_KERNEL);
if (!mp)
return -ENOMEM;
pci = &mp->pci;
pci->dev = dev;
pci->ops = &dw_pcie_ops;
pci->pp.ops = &meson_pcie_host_ops;
pci->num_lanes = 1;
mp->phy = devm_phy_get(dev, "pcie");
if (IS_ERR(mp->phy)) {
dev_err(dev, "get phy failed, %ld\n", PTR_ERR(mp->phy));
return PTR_ERR(mp->phy);
}
mp->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
if (IS_ERR(mp->reset_gpio)) {
dev_err(dev, "get reset gpio failed\n");
return PTR_ERR(mp->reset_gpio);
}
ret = meson_pcie_get_resets(mp);
if (ret) {
dev_err(dev, "get reset resource failed, %d\n", ret);
return ret;
}
ret = meson_pcie_get_mems(pdev, mp);
if (ret) {
dev_err(dev, "get memory resource failed, %d\n", ret);
return ret;
}
ret = meson_pcie_power_on(mp);
if (ret) {
dev_err(dev, "phy power on failed, %d\n", ret);
return ret;
}
ret = meson_pcie_reset(mp);
if (ret) {
dev_err(dev, "reset failed, %d\n", ret);
goto err_phy;
}
ret = meson_pcie_probe_clocks(mp);
if (ret) {
dev_err(dev, "init clock resources failed, %d\n", ret);
goto err_phy;
}
platform_set_drvdata(pdev, mp);
ret = dw_pcie_host_init(&pci->pp);
if (ret < 0) {
dev_err(dev, "Add PCIe port failed, %d\n", ret);
goto err_phy;
}
return 0;
err_phy:
meson_pcie_power_off(mp);
return ret;
}
static const struct of_device_id meson_pcie_of_match[] = {
{
.compatible = "amlogic,axg-pcie",
},
{
.compatible = "amlogic,g12a-pcie",
},
{},
};
MODULE_DEVICE_TABLE(of, meson_pcie_of_match);
static struct platform_driver meson_pcie_driver = {
.probe = meson_pcie_probe,
.driver = {
.name = "meson-pcie",
.of_match_table = meson_pcie_of_match,
},
};
module_platform_driver(meson_pcie_driver);
MODULE_AUTHOR("Yue Wang <yue.wang@amlogic.com>");
MODULE_DESCRIPTION("Amlogic PCIe Controller driver");
MODULE_LICENSE("GPL v2");