usb: dwc3: gadget: Avoid using reserved endpoints on Intel Merrifield

Intel Merrifield SoC uses these endpoints for tracing and they cannot
be re-allocated if being used because the side band flow control signals
are hard wired to certain endpoints:

• 1 High BW Bulk IN (IN#1) (RTIT)
• 1 1KB BW Bulk IN (IN#8) + 1 1KB BW Bulk OUT (Run Control) (OUT#8)

In device mode, since RTIT (EP#1) and EXI/RunControl (EP#8) uses
External Buffer Control (EBC) mode, these endpoints are to be mapped to
EBC mode (to be done by EXI target driver). Additionally TRB for RTIT
and EXI are maintained in STM (System Trace Module) unit and the EXI
target driver will as well configure the TRB location for EP #1 IN
and EP#8 (IN and OUT). Since STM/PTI and EXI hardware blocks manage
these endpoints and interface to OTG3 controller through EBC interface,
there is no need to enable any events (such as XferComplete etc)
for these end points.

Signed-off-by: Andy Shevchenko <[email protected]>
Tested-by: Ferry Toth <[email protected]>
Acked-by: Thinh Nguyen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: andy-shev

drivers/usb/dwc3/dwc3-pci.c

@@ -148,11 +148,21 @@ static const struct property_entry dwc3_pci_intel_byt_properties[] = {
 	{}
 };
 
+/*
+ * Intel Merrifield SoC uses these endpoints for tracing and they cannot
+ * be re-allocated if being used because the side band flow control signals
+ * are hard wired to certain endpoints:
+ * - 1 High BW Bulk IN (IN#1) (RTIT)
+ * - 1 1KB BW Bulk IN (IN#8) + 1 1KB BW Bulk OUT (Run Control) (OUT#8)
+ */
+static const u8 dwc3_pci_mrfld_reserved_endpoints[] = { 3, 16, 17 };
+
 static const struct property_entry dwc3_pci_mrfld_properties[] = {
 	PROPERTY_ENTRY_STRING("dr_mode", "otg"),
 	PROPERTY_ENTRY_STRING("linux,extcon-name", "mrfld_bcove_pwrsrc"),
 	PROPERTY_ENTRY_BOOL("snps,dis_u3_susphy_quirk"),
 	PROPERTY_ENTRY_BOOL("snps,dis_u2_susphy_quirk"),
+	PROPERTY_ENTRY_U8_ARRAY("snps,reserved-endpoints", dwc3_pci_mrfld_reserved_endpoints),
 	PROPERTY_ENTRY_BOOL("snps,usb2-gadget-lpm-disable"),
 	PROPERTY_ENTRY_BOOL("linux,sysdev_is_parent"),
 	{}