[PATCH v2 12/12] xhci: tegra: enable ELPG for runtime/system PM

From: JC Kuo
Date: Mon Aug 31 2020 - 00:41:30 EST

This commit implements the complete programming sequence for ELPG
entry and exit.

1. At ELPG entry, invokes tegra_xusb_padctl_enable_phy_sleepwalk()
and tegra_xusb_padctl_enable_phy_wake() to configure XUSB PADCTL
sleepwalk and wake detection circuits to maintain USB lines level
and respond to wake events (wake-on-connect, wake-on-disconnect,
device-initiated-wake).

2. At ELPG exit, invokes tegra_xusb_padctl_disable_phy_sleepwalk()
and tegra_xusb_padctl_disable_phy_wake() to disarm sleepwalk and
wake detection circuits.

At runtime suspend, XUSB host controller can enter ELPG to reduce
power consumption. When XUSB PADCTL wake detection circuit detects
a wake event, an interrupt will be raised. xhci-tegra driver then
will invoke pm_runtime_resume() for xhci-tegra.

Runtime resume could also be triggered by protocol drivers, this is
the host-initiated-wake event. At runtime resume, xhci-tegra driver
brings XUSB host controller out of ELPG to handle the wake events.

The same ELPG enter/exit procedure will be performed for system
suspend/resume path so USB devices can remain connected across SC7.

Signed-off-by: JC Kuo <jckuo@xxxxxxxxxx>
---
drivers/usb/host/xhci-tegra.c | 391 +++++++++++++++++++++++++++++++---
1 file changed, 361 insertions(+), 30 deletions(-)

diff --git a/drivers/usb/host/xhci-tegra.c b/drivers/usb/host/xhci-tegra.c
index ce6526c2caf6..9530cfc83f45 100644
--- a/drivers/usb/host/xhci-tegra.c
+++ b/drivers/usb/host/xhci-tegra.c
@@ -15,9 +15,11 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_device.h>
+#include <linux/of_irq.h>
#include <linux/phy/phy.h>
#include <linux/phy/tegra/xusb.h>
#include <linux/platform_device.h>
+#include <linux/usb/ch9.h>
#include <linux/pm.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
@@ -224,6 +226,7 @@ struct tegra_xusb {

int xhci_irq;
int mbox_irq;
+ int padctl_irq;

void __iomem *ipfs_base;
void __iomem *fpci_base;
@@ -268,10 +271,13 @@ struct tegra_xusb {
dma_addr_t phys;
} fw;

+ bool suspended;
struct tegra_xusb_context context;
};

static struct hc_driver __read_mostly tegra_xhci_hc_driver;
+static int tegra_xusb_exit_elpg(struct tegra_xusb *tegra, bool runtime);
+static int tegra_xusb_enter_elpg(struct tegra_xusb *tegra, bool runtime);

static inline u32 fpci_readl(struct tegra_xusb *tegra, unsigned int offset)
{
@@ -657,6 +663,9 @@ static irqreturn_t tegra_xusb_mbox_thread(int irq, void *data)

mutex_lock(&tegra->lock);

+ if (pm_runtime_suspended(tegra->dev) || tegra->suspended)
+ goto out;
+
value = fpci_readl(tegra, tegra->soc->mbox.data_out);
tegra_xusb_mbox_unpack(&msg, value);

@@ -670,6 +679,7 @@ static irqreturn_t tegra_xusb_mbox_thread(int irq, void *data)

tegra_xusb_mbox_handle(tegra, &msg);

+out:
mutex_unlock(&tegra->lock);
return IRQ_HANDLED;
}
@@ -812,12 +822,27 @@ static void tegra_xusb_phy_disable(struct tegra_xusb *tegra)

static int tegra_xusb_runtime_suspend(struct device *dev)
{
- return 0;
+ struct tegra_xusb *tegra = dev_get_drvdata(dev);
+ int ret;
+
+ synchronize_irq(tegra->mbox_irq);
+ mutex_lock(&tegra->lock);
+ ret = tegra_xusb_enter_elpg(tegra, true);
+ mutex_unlock(&tegra->lock);
+
+ return ret;
}

static int tegra_xusb_runtime_resume(struct device *dev)
{
- return 0;
+ struct tegra_xusb *tegra = dev_get_drvdata(dev);
+ int err;
+
+ mutex_lock(&tegra->lock);
+ err = tegra_xusb_exit_elpg(tegra, true);
+ mutex_unlock(&tegra->lock);
+
+ return err;
}

#ifdef CONFIG_PM_SLEEP
@@ -1121,6 +1146,22 @@ static int __tegra_xusb_enable_firmware_messages(struct tegra_xusb *tegra)
return err;
}

+static irqreturn_t tegra_xusb_padctl_irq(int irq, void *data)
+{
+ struct tegra_xusb *tegra = data;
+
+ mutex_lock(&tegra->lock);
+ if (tegra->suspended) {
+ mutex_unlock(&tegra->lock);
+ return IRQ_HANDLED;
+ }
+ mutex_unlock(&tegra->lock);
+
+ pm_runtime_resume(tegra->dev);
+
+ return IRQ_HANDLED;
+}
+
static int tegra_xusb_enable_firmware_messages(struct tegra_xusb *tegra)
{
int err;
@@ -1244,6 +1285,51 @@ static void tegra_xhci_id_work(struct work_struct *work)
}
}

+static bool is_usb2_otg_phy(struct tegra_xusb *tegra, int index)
+{
+ return (tegra->usbphy[index] != NULL);
+}
+
+static bool is_usb3_otg_phy(struct tegra_xusb *tegra, int index)
+{
+ struct tegra_xusb_padctl *padctl = tegra->padctl;
+ int i, port;
+
+ for (i = 0; i < tegra->num_usb_phys; i++) {
+ if (is_usb2_otg_phy(tegra, i)) {
+ port = tegra_xusb_padctl_get_usb3_companion(padctl,i);
+ if (index == port)
+ return true;
+ }
+ }
+
+ return false;
+}
+
+static bool is_host_mode_phy(struct tegra_xusb *tegra, int phy_type, int index)
+{
+ if (strcmp(tegra->soc->phy_types[phy_type].name, "hsic") == 0)
+ return true;
+
+ if (strcmp(tegra->soc->phy_types[phy_type].name, "usb2") == 0) {
+ if (is_usb2_otg_phy(tegra, index)) {
+ return ((index == tegra->otg_usb2_port) &&
+ tegra->host_mode);
+ } else
+ return true;
+ }
+
+ if (strcmp(tegra->soc->phy_types[phy_type].name, "usb3") == 0) {
+ if (is_usb3_otg_phy(tegra, index)) {
+ return ((index == tegra->otg_usb3_port) &&
+ tegra->host_mode);
+ } else
+ return true;
+ }
+
+ return false;
+}
+
static int tegra_xusb_get_usb2_port(struct tegra_xusb *tegra,
struct usb_phy *usbphy)
{
@@ -1336,6 +1422,7 @@ static void tegra_xusb_deinit_usb_phy(struct tegra_xusb *tegra)
static int tegra_xusb_probe(struct platform_device *pdev)
{
struct tegra_xusb *tegra;
+ struct device_node *np;
struct resource *regs;
struct xhci_hcd *xhci;
unsigned int i, j, k;
@@ -1383,6 +1470,14 @@ static int tegra_xusb_probe(struct platform_device *pdev)
if (IS_ERR(tegra->padctl))
return PTR_ERR(tegra->padctl);

+ np = of_parse_phandle(pdev->dev.of_node, "nvidia,xusb-padctl", 0);
+ if (!np)
+ return -ENODEV;
+
+ tegra->padctl_irq = of_irq_get(np, 0);
+ if (tegra->padctl_irq < 0)
+ return tegra->padctl_irq;
+
tegra->host_clk = devm_clk_get(&pdev->dev, "xusb_host");
if (IS_ERR(tegra->host_clk)) {
err = PTR_ERR(tegra->host_clk);
@@ -1527,6 +1622,7 @@ static int tegra_xusb_probe(struct platform_device *pdev)
goto put_powerdomains;
}

+ tegra->hcd->skip_phy_initialization = 1;
tegra->hcd->regs = tegra->regs;
tegra->hcd->rsrc_start = regs->start;
tegra->hcd->rsrc_len = resource_size(regs);
@@ -1609,12 +1705,6 @@ static int tegra_xusb_probe(struct platform_device *pdev)
goto put_usb3;
}

- err = tegra_xusb_enable_firmware_messages(tegra);
- if (err < 0) {
- dev_err(&pdev->dev, "failed to enable messages: %d\n", err);
- goto remove_usb3;
- }
-
err = devm_request_threaded_irq(&pdev->dev, tegra->mbox_irq,
tegra_xusb_mbox_irq,
tegra_xusb_mbox_thread, 0,
@@ -1624,12 +1714,40 @@ static int tegra_xusb_probe(struct platform_device *pdev)
goto remove_usb3;
}

+ err = devm_request_threaded_irq(&pdev->dev, tegra->padctl_irq,
+ NULL,
+ tegra_xusb_padctl_irq,
+ IRQF_ONESHOT |
+ IRQF_TRIGGER_HIGH,
+ dev_name(&pdev->dev), tegra);
+ if (err < 0) {
+ dev_err(&pdev->dev, "failed to request padctl IRQ: %d\n", err);
+ goto remove_usb3;
+ }
+
+ err = tegra_xusb_enable_firmware_messages(tegra);
+ if (err < 0) {
+ dev_err(&pdev->dev, "failed to enable messages: %d\n", err);
+ goto remove_usb3;
+ }
+
err = tegra_xusb_init_usb_phy(tegra);
if (err < 0) {
dev_err(&pdev->dev, "failed to init USB PHY: %d\n", err);
goto remove_usb3;
}

+ /* Enable wake for both USB 2.0 and USB 3.0 roothubs */
+ device_init_wakeup(&tegra->hcd->self.root_hub->dev, true);
+ device_init_wakeup(&xhci->shared_hcd->self.root_hub->dev, true);
+ device_init_wakeup(tegra->dev, true);
+
+ pm_runtime_use_autosuspend(tegra->dev);
+ pm_runtime_set_autosuspend_delay(tegra->dev, 2000);
+ pm_runtime_mark_last_busy(tegra->dev);
+ pm_runtime_set_active(tegra->dev);
+ pm_runtime_enable(tegra->dev);
+
return 0;

remove_usb3:
@@ -1665,6 +1783,7 @@ static int tegra_xusb_remove(struct platform_device *pdev)

tegra_xusb_deinit_usb_phy(tegra);

+ pm_runtime_get_sync(&pdev->dev);
usb_remove_hcd(xhci->shared_hcd);
usb_put_hcd(xhci->shared_hcd);
xhci->shared_hcd = NULL;
@@ -1674,8 +1793,8 @@ static int tegra_xusb_remove(struct platform_device *pdev)
dma_free_coherent(&pdev->dev, tegra->fw.size, tegra->fw.virt,
tegra->fw.phys);

- pm_runtime_put_sync(&pdev->dev);
pm_runtime_disable(&pdev->dev);
+ pm_runtime_put(&pdev->dev);

tegra_xusb_powergate_partitions(tegra);

@@ -1717,9 +1836,17 @@ static bool xhci_hub_ports_suspended(struct xhci_hub *hub)
static int tegra_xusb_check_ports(struct tegra_xusb *tegra)
{
struct xhci_hcd *xhci = hcd_to_xhci(tegra->hcd);
+ struct xhci_hub *rhub = xhci_get_rhub(xhci->main_hcd);
+ struct xhci_bus_state *bus_state = &rhub->bus_state;
unsigned long flags;
int err = 0;

+ if (bus_state->bus_suspended) {
+ /* xusb_hub_suspend() has just directed one or more USB2 port(s)
+ * to U3 state, it takes 3ms to enter U3. */
+ usleep_range(3000, 4000);
+ }
+
spin_lock_irqsave(&xhci->lock, flags);

if (!xhci_hub_ports_suspended(&xhci->usb2_rhub) ||
@@ -1765,45 +1892,184 @@ static void tegra_xusb_restore_context(struct tegra_xusb *tegra)
}
}

-static int tegra_xusb_enter_elpg(struct tegra_xusb *tegra, bool wakeup)
+static enum usb_device_speed
+tegra_xhci_portsc_to_speed(struct tegra_xusb *tegra, u32 portsc)
+{
+ if (DEV_LOWSPEED(portsc))
+ return USB_SPEED_LOW;
+ else if (DEV_HIGHSPEED(portsc))
+ return USB_SPEED_HIGH;
+ else if (DEV_FULLSPEED(portsc))
+ return USB_SPEED_FULL;
+ else if (DEV_SUPERSPEED_ANY(portsc))
+ return USB_SPEED_SUPER;
+ else
+ return USB_SPEED_UNKNOWN;
+}
+
+static void tegra_xhci_enable_phy_sleepwalk_wake(struct tegra_xusb *tegra)
+{
+ struct tegra_xusb_padctl *padctl = tegra->padctl;
+ struct xhci_hcd *xhci = hcd_to_xhci(tegra->hcd);
+ enum usb_device_speed speed;
+ struct phy *phy;
+ int index, offset;
+ int i, j, k;
+ struct xhci_hub *rhub;
+ u32 portsc;
+
+ for (i = 0, k = 0; i < tegra->soc->num_types; i++) {
+ if (strcmp(tegra->soc->phy_types[i].name, "usb3") == 0)
+ rhub = &xhci->usb3_rhub;
+ else
+ rhub = &xhci->usb2_rhub;
+
+ if (strcmp(tegra->soc->phy_types[i].name, "hsic") == 0)
+ offset = tegra->soc->ports.usb2.count;
+ else
+ offset = 0;
+
+ for (j = 0; j < tegra->soc->phy_types[i].num; j++) {
+ phy = tegra->phys[k++];
+
+ if (!phy)
+ continue;
+
+ index = j + offset;
+
+ if (index >= rhub->num_ports)
+ continue;
+
+ if (!is_host_mode_phy(tegra, i, j))
+ continue;
+
+ portsc = readl(rhub->ports[index]->addr);
+ speed = tegra_xhci_portsc_to_speed(tegra, portsc);
+ tegra_xusb_padctl_enable_phy_sleepwalk(padctl, phy,
+ speed);
+ tegra_xusb_padctl_enable_phy_wake(padctl, phy);
+ }
+ }
+}
+
+static void tegra_xhci_disable_phy_wake(struct tegra_xusb *tegra)
+{
+ struct tegra_xusb_padctl *padctl = tegra->padctl;
+ int i;
+
+ for (i = 0; i < tegra->num_phys; i++) {
+ if (!tegra->phys[i])
+ continue;
+
+ tegra_xusb_padctl_disable_phy_wake(padctl, tegra->phys[i]);
+ }
+}
+
+static void tegra_xhci_disable_phy_sleepwalk(struct tegra_xusb *tegra)
+{
+ struct tegra_xusb_padctl *padctl = tegra->padctl;
+ int i;
+
+ for (i = 0; i < tegra->num_phys; i++) {
+ if (!tegra->phys[i])
+ continue;
+
+ tegra_xusb_padctl_disable_phy_sleepwalk(padctl, tegra->phys[i]);
+ }
+}
+
+static int tegra_xusb_enter_elpg(struct tegra_xusb *tegra, bool runtime)
{
struct xhci_hcd *xhci = hcd_to_xhci(tegra->hcd);
+ struct device *dev = tegra->dev;
+ bool wakeup = runtime ? true : device_may_wakeup(dev);
+ unsigned int i;
int err;
+ u32 usbcmd;
+
+ dev_dbg(dev, "entering ELPG\n");
+
+ usbcmd = readl(&xhci->op_regs->command);
+ usbcmd &= ~CMD_EIE;
+ writel(usbcmd, &xhci->op_regs->command);

err = tegra_xusb_check_ports(tegra);
if (err < 0) {
dev_err(tegra->dev, "not all ports suspended: %d\n", err);
- return err;
+ goto out;
}

err = xhci_suspend(xhci, wakeup);
if (err < 0) {
dev_err(tegra->dev, "failed to suspend XHCI: %d\n", err);
- return err;
+ goto out;
}

tegra_xusb_save_context(tegra);
- tegra_xusb_phy_disable(tegra);
+
+ if (wakeup)
+ tegra_xhci_enable_phy_sleepwalk_wake(tegra);
+
+ tegra_xusb_powergate_partitions(tegra);
+
+ for (i = 0; i < tegra->num_phys; i++) {
+ if (!tegra->phys[i])
+ continue;
+
+ phy_power_off(tegra->phys[i]);
+ if (!wakeup)
+ phy_exit(tegra->phys[i]);
+ }
tegra_xusb_clk_disable(tegra);

- return 0;
+out:
+ if (!err)
+ dev_dbg(tegra->dev, "entering ELPG done\n");
+ else {
+ usbcmd = readl(&xhci->op_regs->command);
+ usbcmd |= CMD_EIE;
+ writel(usbcmd, &xhci->op_regs->command);
+
+ dev_dbg(tegra->dev, "entering ELPG failed\n");
+ pm_runtime_mark_last_busy(tegra->dev);
+ }
+
+ return err;
}

-static int tegra_xusb_exit_elpg(struct tegra_xusb *tegra, bool wakeup)
+static int tegra_xusb_exit_elpg(struct tegra_xusb *tegra, bool runtime)
{
struct xhci_hcd *xhci = hcd_to_xhci(tegra->hcd);
+ struct device *dev = tegra->dev;
+ bool wakeup = runtime ? true : device_may_wakeup(dev);
+ unsigned int i;
+ u32 usbcmd;
int err;

+ dev_dbg(dev, "exiting ELPG\n");
+ pm_runtime_mark_last_busy(tegra->dev);
+
err = tegra_xusb_clk_enable(tegra);
if (err < 0) {
dev_err(tegra->dev, "failed to enable clocks: %d\n", err);
- return err;
+ goto out;
}

- err = tegra_xusb_phy_enable(tegra);
- if (err < 0) {
- dev_err(tegra->dev, "failed to enable PHYs: %d\n", err);
- goto disable_clk;
+ err = tegra_xusb_unpowergate_partitions(tegra);
+ if (err)
+ goto disable_clks;
+
+ if (wakeup)
+ tegra_xhci_disable_phy_wake(tegra);
+
+ for (i = 0; i < tegra->num_phys; i++) {
+ if (!tegra->phys[i])
+ continue;
+
+ if (!wakeup)
+ phy_init(tegra->phys[i]);
+
+ phy_power_on(tegra->phys[i]);
}

tegra_xusb_config(tegra);
@@ -1821,31 +2087,78 @@ static int tegra_xusb_exit_elpg(struct tegra_xusb *tegra, bool wakeup)
goto disable_phy;
}

- err = xhci_resume(xhci, true);
+ if (wakeup)
+ tegra_xhci_disable_phy_sleepwalk(tegra);
+
+ err = xhci_resume(xhci, 0);
if (err < 0) {
dev_err(tegra->dev, "failed to resume XHCI: %d\n", err);
goto disable_phy;
}

- return 0;
+ usbcmd = readl(&xhci->op_regs->command);
+ usbcmd |= CMD_EIE;
+ writel(usbcmd, &xhci->op_regs->command);
+
+ goto out;

disable_phy:
- tegra_xusb_phy_disable(tegra);
-disable_clk:
+ for (i = 0; i < tegra->num_phys; i++) {
+ if (!tegra->phys[i])
+ continue;
+
+ phy_power_off(tegra->phys[i]);
+ if (!wakeup)
+ phy_exit(tegra->phys[i]);
+ }
+ tegra_xusb_powergate_partitions(tegra);
+disable_clks:
tegra_xusb_clk_disable(tegra);
+out:
+ if (!err)
+ dev_dbg(dev, "exiting ELPG done\n");
+ else
+ dev_dbg(dev, "exiting ELPG failed\n");
+
return err;
}

static int tegra_xusb_suspend(struct device *dev)
{
struct tegra_xusb *tegra = dev_get_drvdata(dev);
- bool wakeup = device_may_wakeup(dev);
int err;

synchronize_irq(tegra->mbox_irq);
-
mutex_lock(&tegra->lock);
- err = tegra_xusb_enter_elpg(tegra, wakeup);
+
+ if (pm_runtime_suspended(dev)) {
+ err = tegra_xusb_exit_elpg(tegra, true);
+ if (err < 0)
+ goto out;
+ }
+
+ err = tegra_xusb_enter_elpg(tegra, false);
+ if (err < 0) {
+ if (pm_runtime_suspended(dev)) {
+ pm_runtime_disable(dev);
+ pm_runtime_set_active(dev);
+ pm_runtime_enable(dev);
+ }
+
+ goto out;
+ }
+
+out:
+ if (!err) {
+ tegra->suspended = true;
+ pm_runtime_disable(dev);
+
+ if (device_may_wakeup(dev)) {
+ if (enable_irq_wake(tegra->padctl_irq))
+ dev_err(dev, "failed to enable padctl wakes\n");
+ }
+ }
+
mutex_unlock(&tegra->lock);

return err;
@@ -1854,14 +2167,32 @@ static int tegra_xusb_suspend(struct device *dev)
static int tegra_xusb_resume(struct device *dev)
{
struct tegra_xusb *tegra = dev_get_drvdata(dev);
- bool wakeup = device_may_wakeup(dev);
int err;

mutex_lock(&tegra->lock);
- err = tegra_xusb_exit_elpg(tegra, wakeup);
+
+ if (!tegra->suspended) {
+ mutex_unlock(&tegra->lock);
+ return 0;
+ }
+
+ err = tegra_xusb_exit_elpg(tegra, false);
+ if (err < 0) {
+ mutex_unlock(&tegra->lock);
+ return err;
+ }
+
+ if (device_may_wakeup(dev)) {
+ if (disable_irq_wake(tegra->padctl_irq))
+ dev_err(dev, "failed to disable padctl wakes\n");
+ }
+ tegra->suspended = false;
mutex_unlock(&tegra->lock);

- return err;
+ pm_runtime_set_active(dev);
+ pm_runtime_enable(dev);
+
+ return 0;
}
#endif

--
2.25.1