[PATCH v3 1/2] usb: dwc3: Add a quirk to set GUCTL.SPRSCTRLTRANSEN bit.

[Yaqin Pan <akingchen@vivo.com>]

This quirk is only for dwc3 host mode.
the dwc3 controller can't emurate some devices successfully.
For example, TF card reader (aaaa:8816):
failed log
usb 1-1: new high-speed USB device number 2 using xhci-hcd
usb 1-1: device descriptor read/all, error -110
From the usb analyzer, always return NAK in the data phase.
if enable the GUCTL.SPRSCTRLTRANSEN bit. then the log is:
usb 2-1: new high-speed USB device number 3 using xhci-hcd
usb 2-1: New USB device found, idVendor=aaaa,
idProduct=8816, bcdDevice=13.08
usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 2-1: Product: MXT USB Device
usb 2-1: Manufacturer: MXTronics
usb 2-1: SerialNumber: 150101v01
usb 2-1: New USB device found, VID=aaaa, PID=8816

Some devices are slow in responding to Control transfers.
Scheduling mulitiple transactions in one microframe/frame
can cause the devices to misbehave. if this qurik is enabled,
the host controller schedules transations for a Control transfer
in defferent microframes/frame.

Signed-off-by: Yaqin Pan <akingchen@vivo.com>
---
 drivers/usb/dwc3/core.c | 4 ++++
 drivers/usb/dwc3/core.h | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index ba74ad7f6995..93ac2c79a2c0 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1071,6 +1071,8 @@ static int dwc3_core_init(struct dwc3 *dwc)
 		 * packet with Retry=1 & Nump != 0)
 		 */
 		reg |= DWC3_GUCTL_HSTINAUTORETRY;
+		if (dwc->sprs_ctrl_trans_quirk)
+			reg |= DWC3_GUCTL_SPRSCTRLTRANSEN;
 
 		dwc3_writel(dwc->regs, DWC3_GUCTL, reg);
 	}
@@ -1377,6 +1379,8 @@ static void dwc3_get_properties(struct dwc3 *dwc)
 
 	dwc->dis_split_quirk = device_property_read_bool(dev,
 				"snps,dis-split-quirk");
+	dwc->sprs_ctrl_trans_quirk = device_property_read_bool(dev,
+				"snps,sprs-ctrl-trans-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 5991766239ba..6048087df1d1 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -254,6 +254,7 @@
 
 /* Global User Control Register */
 #define DWC3_GUCTL_HSTINAUTORETRY	BIT(14)
+#define DWC3_GUCTL_SPRSCTRLTRANSEN	BIT(17)
 
 /* Global User Control 1 Register */
 #define DWC3_GUCTL1_PARKMODE_DISABLE_SS	BIT(17)
@@ -1077,6 +1078,7 @@ struct dwc3_scratchpad_array {
  *	3	- Reserved
  * @dis_metastability_quirk: set to disable metastability quirk.
  * @dis_split_quirk: set to disable split boundary.
+ * @sprs_ctrl_trans_quirk: set to enable sparse control transaction quirk.
  * @imod_interval: set the interrupt moderation interval in 250ns
  *			increments or 0 to disable.
  */
@@ -1279,6 +1281,7 @@ struct dwc3 {
 	unsigned		dis_metastability_quirk:1;
 
 	unsigned		dis_split_quirk:1;
+	unsigned		sprs_ctrl_trans_quirk:1;
 	unsigned		async_callbacks:1;
 
 	u16			imod_interval;
-- 
2.17.1