Patch "usb: dwc3: core: Skip setting event buffers for host only controllers" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    usb: dwc3: core: Skip setting event buffers for host only controllers

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     usb-dwc3-core-skip-setting-event-buffers-for-host-on.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 04189db474048168da841a0820f4dbefb63d0c61
Author: Krishna Kurapati <quic_kriskura@xxxxxxxxxxx>
Date:   Sat Apr 20 10:18:55 2024 +0530

    usb: dwc3: core: Skip setting event buffers for host only controllers
    
    [ Upstream commit 89d7f962994604a3e3d480832788d06179abefc5 ]
    
    On some SoC's like SA8295P where the tertiary controller is host-only
    capable, GEVTADDRHI/LO, GEVTSIZ, GEVTCOUNT registers are not accessible.
    Trying to access them leads to a crash.
    
    For DRD/Peripheral supported controllers, event buffer setup is done
    again in gadget_pullup. Skip setup or cleanup of event buffers if
    controller is host-only capable.
    
    Suggested-by: Johan Hovold <johan@xxxxxxxxxx>
    Signed-off-by: Krishna Kurapati <quic_kriskura@xxxxxxxxxxx>
    Acked-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>
    Reviewed-by: Johan Hovold <johan+linaro@xxxxxxxxxx>
    Reviewed-by: Bjorn Andersson <andersson@xxxxxxxxxx>
    Tested-by: Johan Hovold <johan+linaro@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20240420044901.884098-4-quic_kriskura@xxxxxxxxxxx
    Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 12e72e804278e..cbe475134b3c6 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -391,6 +391,13 @@ static void dwc3_free_event_buffers(struct dwc3 *dwc)
 static int dwc3_alloc_event_buffers(struct dwc3 *dwc, unsigned length)
 {
 	struct dwc3_event_buffer *evt;
+	unsigned int hw_mode;
+
+	hw_mode = DWC3_GHWPARAMS0_MODE(dwc->hwparams.hwparams0);
+	if (hw_mode == DWC3_GHWPARAMS0_MODE_HOST) {
+		dwc->ev_buf = NULL;
+		return 0;
+	}
 
 	evt = dwc3_alloc_one_event_buffer(dwc, length);
 	if (IS_ERR(evt)) {
@@ -412,6 +419,9 @@ int dwc3_event_buffers_setup(struct dwc3 *dwc)
 {
 	struct dwc3_event_buffer	*evt;
 
+	if (!dwc->ev_buf)
+		return 0;
+
 	evt = dwc->ev_buf;
 	evt->lpos = 0;
 	dwc3_writel(dwc->regs, DWC3_GEVNTADRLO(0),
@@ -429,6 +439,9 @@ void dwc3_event_buffers_cleanup(struct dwc3 *dwc)
 {
 	struct dwc3_event_buffer	*evt;
 
+	if (!dwc->ev_buf)
+		return;
+
 	evt = dwc->ev_buf;
 
 	evt->lpos = 0;