[PATCH] usb: dwc3: core: workaround for hibernation D3 entry timeout

[joswang]

From: joswang <joswang@xxxxxxxxxx>

In the case of enable hibernation, there is an issue with
the DWC31 2.00a and earlier versions where the controller
link power state transition from P3/P3CPM/P4 to P2 may take
longer than expected, ultimately resulting in the hibernation
D3 entering time exceeding the expected 10ms.

Synopsys workaround:
If the PHY supports direct P3 to P2 transition, program
GUSB3PIPECTL.P3P2Tran0K=1. However, note that as per PIPE4
Specification, direct transition from P3 to P2 is illegal.

Therefore, adding p3p2tranok quirk for workaround hibernation
D3 exceeded the expected entry time.

Signed-off-by: joswang <joswang@xxxxxxxxxx>
---
 drivers/usb/dwc3/core.c | 5 +++++
 drivers/usb/dwc3/core.h | 4 ++++
 2 files changed, 9 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 7ee61a89520b..3a8fbc2d6b99 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -666,6 +666,9 @@ static int dwc3_ss_phy_setup(struct dwc3 *dwc, int index)
 	if (dwc->dis_del_phy_power_chg_quirk)
 		reg &= ~DWC3_GUSB3PIPECTL_DEPOCHANGE;
 
+	if (dwc->p2p3tranok_quirk)
+		reg |= DWC3_GUSB3PIPECTL_P3P2TRANOK;
+
 	dwc3_writel(dwc->regs, DWC3_GUSB3PIPECTL(index), reg);
 
 	return 0;
@@ -1715,6 +1718,8 @@ static void dwc3_get_properties(struct dwc3 *dwc)
 
 	dwc->dis_split_quirk = device_property_read_bool(dev,
 				"snps,dis-split-quirk");
+	dwc->p2p3tranok_quirk = device_property_read_bool(dev,
+				"snps,p2p3tranok-quirk");
 
 	dwc->lpm_nyet_threshold = lpm_nyet_threshold;
 	dwc->tx_de_emphasis = tx_de_emphasis;
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 3781c736c1a1..2810dce8b42e 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -327,6 +327,7 @@
 #define DWC3_GUSB3PIPECTL_DEP1P2P3_EN	DWC3_GUSB3PIPECTL_DEP1P2P3(1)
 #define DWC3_GUSB3PIPECTL_DEPOCHANGE	BIT(18)
 #define DWC3_GUSB3PIPECTL_SUSPHY	BIT(17)
+#define DWC3_GUSB3PIPECTL_P3P2TRANOK	BIT(11)
 #define DWC3_GUSB3PIPECTL_LFPSFILT	BIT(9)
 #define DWC3_GUSB3PIPECTL_RX_DETOPOLL	BIT(8)
 #define DWC3_GUSB3PIPECTL_TX_DEEPH_MASK	DWC3_GUSB3PIPECTL_TX_DEEPH(3)
@@ -1132,6 +1133,8 @@ struct dwc3_scratchpad_array {
  *			instances in park mode.
  * @parkmode_disable_hs_quirk: set if we need to disable all HishSpeed
  *			instances in park mode.
+ * @p2p3tranok_quirk: set if Controller transitions directly from phy
+ *			power state P2 to P3 or from state P3 to P2.
  * @gfladj_refclk_lpm_sel: set if we need to enable SOF/ITP counter
  *                          running based on ref_clk
  * @tx_de_emphasis_quirk: set if we enable Tx de-emphasis quirk
@@ -1361,6 +1364,7 @@ struct dwc3 {
 	unsigned		ulpi_ext_vbus_drv:1;
 	unsigned		parkmode_disable_ss_quirk:1;
 	unsigned		parkmode_disable_hs_quirk:1;
+	unsigned		p2p3tranok_quirk:1;
 	unsigned		gfladj_refclk_lpm_sel:1;
 
 	unsigned		tx_de_emphasis_quirk:1;
-- 
2.17.1