linux-kernel - [PATCH 3/3] usb: dwc3: gadget: Add support for disabling U1 and U2 entries

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Date:   Thu, 2 May 2019 15:50:23 +0530
From:   Anurag Kumar Vulisha <anurag.kumar.vulisha@...inx.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Felipe Balbi <balbi@...nel.org>
CC:     <linux-usb@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <v.anuragkumar@...il.com>,
        Anurag Kumar Vulisha <anurag.kumar.vulisha@...inx.com>
Subject: [PATCH 3/3] usb: dwc3: gadget: Add support for disabling U1 and U2 entries

Gadget applications may have a requirement to disable the U1 and U2
entry based on the usecase. For example, when performing performance
benchmarking on mass storage gadget the U1 and U2 entries can be disabled.
Another example is when periodic transfers like ISOC transfers are used
with bInterval of 1 which doesn't require the link to enter into U1 or U2
state (since ping is issued from host for every uframe interval). In this
case the U1 and U2 entry can be disabled. This can be done by setting
U1DevExitLat and U2DevExitLat values to 0 in the BOS descriptor. Host on
seeing 0 value for U1DevExitLat and U2DevExitLat, it doesn't send SET_SEL
commands to the gadget. Thus entry of U1 and U2 states can be avioded.
This patch updates the same

Signed-off-by: Anurag Kumar Vulisha <anurag.kumar.vulisha@...inx.com>
---
 drivers/usb/dwc3/core.c   |  4 ++++
 drivers/usb/dwc3/core.h   |  4 ++++
 drivers/usb/dwc3/gadget.c | 19 +++++++++++++++++++
 drivers/usb/dwc3/gadget.h |  6 ++++++
 4 files changed, 33 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index a1b126f..4f0912c 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1285,6 +1285,10 @@ static void dwc3_get_properties(struct dwc3 *dwc)
 				"snps,dis_u2_susphy_quirk");
 	dwc->dis_enblslpm_quirk = device_property_read_bool(dev,
 				"snps,dis_enblslpm_quirk");
+	dwc->dis_u1_entry_quirk = device_property_read_bool(dev,
+				"snps,dis_u1_entry_quirk");
+	dwc->dis_u2_entry_quirk = device_property_read_bool(dev,
+				"snps,dis_u2_entry_quirk");
 	dwc->dis_rxdet_inp3_quirk = device_property_read_bool(dev,
 				"snps,dis_rxdet_inp3_quirk");
 	dwc->dis_u2_freeclk_exists_quirk = device_property_read_bool(dev,
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 1528d39..fa398e2 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1015,6 +1015,8 @@ struct dwc3_scratchpad_array {
  * @dis_u2_susphy_quirk: set if we disable usb2 suspend phy
  * @dis_enblslpm_quirk: set if we clear enblslpm in GUSB2PHYCFG,
  *                      disabling the suspend signal to the PHY.
+ * @dis_u1_entry_quirk: set if link entering into U1 state needs to be disabled.
+ * @dis_u2_entry_quirk: set if link entering into U2 state needs to be disabled.
  * @dis_rxdet_inp3_quirk: set if we disable Rx.Detect in P3
  * @dis_u2_freeclk_exists_quirk : set if we clear u2_freeclk_exists
  *			in GUSB2PHYCFG, specify that USB2 PHY doesn't
@@ -1206,6 +1208,8 @@ struct dwc3 {
 	unsigned		dis_u3_susphy_quirk:1;
 	unsigned		dis_u2_susphy_quirk:1;
 	unsigned		dis_enblslpm_quirk:1;
+	unsigned		dis_u1_entry_quirk:1;
+	unsigned		dis_u2_entry_quirk:1;
 	unsigned		dis_rxdet_inp3_quirk:1;
 	unsigned		dis_u2_freeclk_exists_quirk:1;
 	unsigned		dis_del_phy_power_chg_quirk:1;
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index e293400..f2d3112 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2073,6 +2073,24 @@ static int dwc3_gadget_stop(struct usb_gadget *g)
 	return 0;
 }
 
+static void dwc3_gadget_config_params(struct usb_gadget *g,
+				      struct usb_dcd_config_params *params)
+{
+	struct dwc3		*dwc = gadget_to_dwc(g);
+
+	/* U1 Device exit Latency */
+	if (dwc->dis_u1_entry_quirk)
+		params->bU1devExitLat = 0;
+	else
+		params->bU1devExitLat = DWC3_DEFAULT_U1_DEV_EXIT_LAT;
+
+	/* U2 Device exit Latency */
+	if (dwc->dis_u2_entry_quirk)
+		params->bU2DevExitLat = 0;
+	else
+		params->bU2DevExitLat = DWC3_DEFAULT_U2_DEV_EXIT_LAT;
+}
+
 static void dwc3_gadget_set_speed(struct usb_gadget *g,
 				  enum usb_device_speed speed)
 {
@@ -2142,6 +2160,7 @@ static const struct usb_gadget_ops dwc3_gadget_ops = {
 	.udc_start		= dwc3_gadget_start,
 	.udc_stop		= dwc3_gadget_stop,
 	.udc_set_speed		= dwc3_gadget_set_speed,
+	.get_config_params	= dwc3_gadget_config_params,
 };
 
 /* -------------------------------------------------------------------------- */
diff --git a/drivers/usb/dwc3/gadget.h b/drivers/usb/dwc3/gadget.h
index 3ed738e..5faf4d1 100644
--- a/drivers/usb/dwc3/gadget.h
+++ b/drivers/usb/dwc3/gadget.h
@@ -48,6 +48,12 @@ struct dwc3;
 /* DEPXFERCFG parameter 0 */
 #define DWC3_DEPXFERCFG_NUM_XFER_RES(n)	((n) & 0xffff)
 
+/* U1 Device exit Latency */
+#define DWC3_DEFAULT_U1_DEV_EXIT_LAT	0x0A	/* Less then 10 microsec */
+
+/* U2 Device exit Latency */
+#define DWC3_DEFAULT_U2_DEV_EXIT_LAT	0x1FF	/* Less then 511 microsec */
+
 /* -------------------------------------------------------------------------- */
 
 #define to_dwc3_request(r)	(container_of(r, struct dwc3_request, request))
-- 
2.1.1