[PATCH v2 1/2] usb: dwc2: fix fifo reinit in dwc2_hsotg_core_init_disconnected

[Fabrice Gasnier]

Currently, the fifo gets re-init, with a running DMA, e.g. when
using_desc_dma():
- dwc2_hsotg_init_fifo -> Flushes the FIFO, DMA may run in parallel
- DCFG_DESCDMA_EN gets cleared (e.g. disables dma desc)
- then DCFG_DESCDMA_EN gets set back again.

So move the dwc2_hsotg_init_fifo() call after DCFG_DESCDMA_EN gets
cleared e.g. DCFG write. Then the FIFO can be flushed safely, before
DCFG_DESCDMA_EN is set back on.

A BNA interrupt may happen on EP0, before this change. When it happens
we can't recover to a working device.

Fixes: a5c18f113150 ("usb: dwc2: gadget: Enable descriptor DMA mode")
Cc: stable@xxxxxxxxxxxxxxx
Acked-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxxxxxxx>
---
Changes in v2:
- Update Fixes tag and collect Thinh's Acked-by tag.
---
 drivers/usb/dwc2/gadget.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index 6c8a9f05fff0..bdabf3c39da1 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -3486,8 +3486,6 @@ void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *hsotg,
 
 	dwc2_phy_init(hsotg, true);
 
-	dwc2_hsotg_init_fifo(hsotg);
-
 	if (!is_usb_reset) {
 		dwc2_set_bit(hsotg, DCTL, DCTL_SFTDISCON);
 		if (hsotg->params.eusb2_disc)
@@ -3515,6 +3513,8 @@ void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *hsotg,
 
 	dwc2_writel(hsotg, dcfg,  DCFG);
 
+	dwc2_hsotg_init_fifo(hsotg);
+
 	/* Clear any pending OTG interrupts */
 	dwc2_writel(hsotg, 0xffffffff, GOTGINT);
 

-- 
2.43.0