usb: dwc2: reset dwc2 core before dwc2_get_hwparams()

We initiate dwc2 usb controller in BIOS, dwc2_core_reset() should
be called before dwc2_get_hwparams() to reset core registers to
default value. Without this the FIFO setting might be incorrect
because calculating FIFO size need power-on value of
GRXFSIZ/GNPTXFSIZ/HPTXFSIZ registers.

This patch could avoid warnning massage like in rk3288 platform:
[    2.074764] dwc2 ff580000.usb: 256 invalid for
host_perio_tx_fifo_size. Check HW configuration.

Signed-off-by: Yunzhi Li <lyz@rock-chips.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

3 files changed, 8 insertions, 1 deletions

diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c
index 0bc1c0ed12eb..0a584ecb233f 100644
--- a/drivers/usb/dwc2/core.c
+++ b/drivers/usb/dwc2/core.c
@@ -481,7 +481,7 @@ static void dwc2_init_fs_ls_pclk_sel(struct dwc2_hsotg *hsotg)
  * Do core a soft reset of the core.  Be careful with this because it
  * resets all the internal state machines of the core.
  */
-static int dwc2_core_reset(struct dwc2_hsotg *hsotg)
+int dwc2_core_reset(struct dwc2_hsotg *hsotg)
 {
         u32 greset;
         int count = 0;
diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index 05f01785de05..d1d855af63e6 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -880,6 +880,7 @@ enum dwc2_halt_status {
  * The following functions support initialization of the core driver component
  * and the DWC_otg controller
  */
+extern int dwc2_core_reset(struct dwc2_hsotg *hsotg);
 extern void dwc2_core_host_init(struct dwc2_hsotg *hsotg);
 extern int dwc2_enter_hibernation(struct dwc2_hsotg *hsotg);
 extern int dwc2_exit_hibernation(struct dwc2_hsotg *hsotg, bool restore);
diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
index 5df2adf6f4e7..a72302d740dd 100644
--- a/drivers/usb/dwc2/platform.c
+++ b/drivers/usb/dwc2/platform.c
@@ -456,6 +456,12 @@ static int dwc2_driver_probe(struct platform_device *dev)
         if (retval)
                 return retval;
 
+        /*
+         * Reset before dwc2_get_hwparams() then it could get power-on real
+         * reset value form registers.
+         */
+        dwc2_core_reset(hsotg);
+
         /* Detect config values from hardware */
         retval = dwc2_get_hwparams(hsotg);
         if (retval)