[PATCH 06/15] usb: dwc2: Clear fifo_map when resetting core.

Artur Petrosyan
2021-04-15T05:40:20Z

Switching from device mode to host mode by disconnecting
device cable core enters and exits form hibernation.
However, the fifo map remains not cleared. It results
to a WARNING (WARNING: CPU: 5 PID: 0 at drivers/usb/dwc2/
gadget.c:307 dwc2_hsotg_init_fifo+0x12/0x152 [dwc2])
if in host mode we disconnect the micro a to b host
cable. Because core reset occurs.

To avoid the WARNING, fifo_map should be cleared
in dwc2_core_reset() function by taking into account configs.
fifo_map must be cleared only if driver is configured in
"CONFIG_USB_DWC2_PERIPHERAL" or "CONFIG_USB_DWC2_DUAL_ROLE"
mode.

- Added "static inline void dwc2_clear_fifo_map()" helper
function to clear fifo_map with peripheral or dual role mode.

- Added a dummy version of "dwc2_clear_fifo_map()" helper
for host-only mode.

Signed-off-by: Artur Petrosyan <Arthur.Petrosyan@synopsys.com>
Acked-by: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>
---
drivers/usb/dwc2/core.c | 16 ++++++++++++++++
drivers/usb/dwc2/core.h | 3 +++
2 files changed, 19 insertions(+)

diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c
index cb65f7f60573..eccd96fa164e 100644
--- a/drivers/usb/dwc2/core.c
+++ b/drivers/usb/dwc2/core.c
@@ -470,6 +470,22 @@ int dwc2_core_reset(struct dwc2_hsotg *hsotg, bool skip_wait)
dwc2_writel(hsotg, greset, GRSTCTL);
}

+ /*
+ * Switching from device mode to host mode by disconnecting
+ * device cable core enters and exits form hibernation.
+ * However, the fifo map remains not cleared. It results
+ * to a WARNING (WARNING: CPU: 5 PID: 0 at drivers/usb/dwc2/
+ * gadget.c:307 dwc2_hsotg_init_fifo+0x12/0x152 [dwc2])
+ * if in host mode we disconnect the micro a to b host
+ * cable. Because core reset occurs.
+ * To avoid the WARNING, fifo_map should be cleared
+ * in dwc2_core_reset() function by taking into account configs.
+ * fifo_map must be cleared only if driver is configured in
+ * "CONFIG_USB_DWC2_PERIPHERAL" or "CONFIG_USB_DWC2_DUAL_ROLE"
+ * mode.
+ */
+ dwc2_clear_fifo_map(hsotg);
+
/* Wait for AHB master IDLE state */
if (dwc2_hsotg_wait_bit_set(hsotg, GRSTCTL, GRSTCTL_AHBIDLE, 10000)) {
dev_warn(hsotg->dev, "%s: HANG! AHB Idle timeout GRSTCTL GRSTCTL_AHBIDLE\n",
diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index 8c12b3061f7f..e1f432095565 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -1423,6 +1423,8 @@ int dwc2_hsotg_tx_fifo_total_depth(struct dwc2_hsotg *hsotg);
int dwc2_hsotg_tx_fifo_average_depth(struct dwc2_hsotg *hsotg);
void dwc2_gadget_init_lpm(struct dwc2_hsotg *hsotg);
void dwc2_gadget_program_ref_clk(struct dwc2_hsotg *hsotg);
+static inline void dwc2_clear_fifo_map(struct dwc2_hsotg *hsotg)
+{ hsotg->fifo_map = 0; }
#else
static inline int dwc2_hsotg_remove(struct dwc2_hsotg *dwc2)
{ return 0; }
@@ -1467,6 +1469,7 @@ static inline int dwc2_hsotg_tx_fifo_average_depth(struct dwc2_hsotg *hsotg)
{ return 0; }
static inline void dwc2_gadget_init_lpm(struct dwc2_hsotg *hsotg) {}
static inline void dwc2_gadget_program_ref_clk(struct dwc2_hsotg *hsotg) {}
+static inline void dwc2_clear_fifo_map(struct dwc2_hsotg *hsotg) {}
#endif

#if IS_ENABLED(CONFIG_USB_DWC2_HOST) || IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE)
--
2.25.1