Commit c40cf770 authored by Douglas Anderson's avatar Douglas Anderson Committed by Felipe Balbi
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usb: dwc2: optionally assert phy reset when waking up

On the rk3288 USB host-only port (the one that's not the OTG-enabled
port) the PHY can get into a bad state when a wakeup is asserted (not
just a wakeup from full system suspend but also a wakeup from

We can get the PHY out of its bad state by asserting its "port reset",
but unfortunately that seems to assert a reset onto the USB bus so it
could confuse things if we don't actually deenumerate / reenumerate the

We can also get the PHY out of its bad state by fully resetting it using
the reset from the CRU (clock reset unit), which does a more full
reset.  The CRU-based reset appears to actually cause devices on the bus
to be removed and reinserted, which fixes the problem (albeit in a hacky

It's unfortunate that we need to do a full re-enumeration of devices at
wakeup time, but this is better than alternative of letting the bus get
Signed-off-by: default avatarDouglas Anderson <>
Signed-off-by: default avatarYunzhi Li <>
Signed-off-by: default avatarFelipe Balbi <>
parent cc389eaa
......@@ -859,6 +859,8 @@ struct dwc2_hregs_backup {
* @gadget_enabled: Peripheral mode sub-driver initialization indicator.
* @ll_hw_enabled: Status of low-level hardware resources.
* @hibernated: True if core is hibernated
* @reset_phy_on_wake: Quirk saying that we should assert PHY reset on a
* remote wakeup.
* @frame_number: Frame number read from the core. For both device
* and host modes. The value ranges are from 0
......@@ -972,6 +974,7 @@ struct dwc2_hregs_backup {
* @status_buf_dma: DMA address for status_buf
* @start_work: Delayed work for handling host A-cable connection
* @reset_work: Delayed work for handling a port reset
* @phy_reset_work: Work structure for doing a PHY reset
* @otg_port: OTG port number
* @frame_list: Frame list
* @frame_list_dma: Frame list DMA address
......@@ -1045,6 +1048,7 @@ struct dwc2_hsotg {
unsigned int gadget_enabled:1;
unsigned int ll_hw_enabled:1;
unsigned int hibernated:1;
unsigned int reset_phy_on_wake:1;
u16 frame_number;
struct phy *phy;
......@@ -1147,6 +1151,7 @@ struct dwc2_hsotg {
struct delayed_work start_work;
struct delayed_work reset_work;
struct work_struct phy_reset_work;
u8 otg_port;
u32 *frame_list;
dma_addr_t frame_list_dma;
......@@ -1431,6 +1436,8 @@ int dwc2_restore_host_registers(struct dwc2_hsotg *hsotg);
int dwc2_host_enter_hibernation(struct dwc2_hsotg *hsotg);
int dwc2_host_exit_hibernation(struct dwc2_hsotg *hsotg,
int rem_wakeup, int reset);
static inline void dwc2_host_schedule_phy_reset(struct dwc2_hsotg *hsotg)
{ schedule_work(&hsotg->phy_reset_work); }
static inline int dwc2_hcd_get_frame_number(struct dwc2_hsotg *hsotg)
{ return 0; }
......@@ -1454,6 +1461,7 @@ static inline int dwc2_host_enter_hibernation(struct dwc2_hsotg *hsotg)
static inline int dwc2_host_exit_hibernation(struct dwc2_hsotg *hsotg,
int rem_wakeup, int reset)
{ return 0; }
static inline void dwc2_host_schedule_phy_reset(struct dwc2_hsotg *hsotg) {}
......@@ -435,6 +435,18 @@ static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg)
/* Restart the Phy Clock */
pcgcctl &= ~PCGCTL_STOPPCLK;
dwc2_writel(hsotg, pcgcctl, PCGCTL);
* If we've got this quirk then the PHY is stuck upon
* wakeup. Assert reset. This will propagate out and
* eventually we'll re-enumerate the device. Not great
* but the best we can do. We can't call phy_reset()
* at interrupt time but there's no hurry, so we'll
* schedule it for later.
if (hsotg->reset_phy_on_wake)
jiffies + msecs_to_jiffies(71));
} else {
......@@ -4376,6 +4376,17 @@ static void dwc2_hcd_reset_func(struct work_struct *work)
spin_unlock_irqrestore(&hsotg->lock, flags);
static void dwc2_hcd_phy_reset_func(struct work_struct *work)
struct dwc2_hsotg *hsotg = container_of(work, struct dwc2_hsotg,
int ret;
ret = phy_reset(hsotg->phy);
if (ret)
dev_warn(hsotg->dev, "PHY reset failed\n");
* =========================================================================
* Linux HC Driver Functions
......@@ -5152,6 +5163,8 @@ static void dwc2_hcd_free(struct dwc2_hsotg *hsotg)
......@@ -5293,11 +5306,10 @@ int dwc2_hcd_init(struct dwc2_hsotg *hsotg)
hsotg->hc_ptr_array[i] = channel;
/* Initialize hsotg start work */
/* Initialize work */
INIT_DELAYED_WORK(&hsotg->start_work, dwc2_hcd_start_func);
/* Initialize port reset work */
INIT_DELAYED_WORK(&hsotg->reset_work, dwc2_hcd_reset_func);
INIT_WORK(&hsotg->phy_reset_work, dwc2_hcd_phy_reset_func);
* Allocate space for storing data on status transactions. Normally no
......@@ -481,6 +481,15 @@ static int dwc2_driver_probe(struct platform_device *dev)
hsotg->gadget_enabled = 1;
hsotg->reset_phy_on_wake =
if (hsotg->reset_phy_on_wake && !hsotg->phy) {
"Quirk reset-phy-on-wake only supports generic PHYs\n");
hsotg->reset_phy_on_wake = false;
if (hsotg->dr_mode != USB_DR_MODE_PERIPHERAL) {
retval = dwc2_hcd_init(hsotg);
if (retval) {
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