[PATCH] usb: dwc2: gadget: respect driver's max_speed

From: John Keeping <john@metanate.com>
To: Minas Harutyunyan <hminas@synopsys.com>
Cc: John Keeping <john@metanate.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] usb: dwc2: gadget: respect driver's max_speed
Date: Fri,  5 Nov 2021 17:23:04 +0000	[thread overview]
Message-ID: <20211105172304.1308458-1-john@metanate.com> (raw)

UDCs should not enumerate faster than the max_speed set by the gadget
driver.  Use this to further restrict the speed set in the DWC2
parameters so that the device will not connect faster than is supported
by the gadget driver.

For configfs-based composite devices this can be set via the max_speed
configfs file.

Signed-off-by: John Keeping <john@metanate.com>
---
 drivers/usb/dwc2/gadget.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index 744539b78f6c..1f39c2f1be8e 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -3377,6 +3377,7 @@ void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *hsotg,
 	u32 val;
 	u32 usbcfg;
 	u32 dcfg = 0;
+	u8 speed;
 	int ep;
 
 	/* Kill any ep0 requests as controller will be reinitialized */
@@ -3418,7 +3419,22 @@ void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *hsotg,
 
 	dcfg |= DCFG_EPMISCNT(1);
 
-	switch (hsotg->params.speed) {
+	speed = hsotg->params.speed;
+	if (hsotg->driver) {
+		switch (hsotg->driver->max_speed) {
+		case USB_SPEED_LOW:
+			speed = DWC2_SPEED_PARAM_LOW;
+			break;
+		case USB_SPEED_FULL:
+			if (speed != USB_SPEED_LOW)
+				speed = DWC2_SPEED_PARAM_FULL;
+			break;
+		default:
+			break;
+		}
+	}
+
+	switch (speed) {
 	case DWC2_SPEED_PARAM_LOW:
 		dcfg |= DCFG_DEVSPD_LS;
 		break;
-- 
2.33.1

