Before flushing fifos required to check AHB master state and
flush when AHB master is in IDLE state.
Signed-off-by: Minas Harutyunyan <hmi...@synopsys.com>
---
 drivers/usb/dwc2/core.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c
index dbca3b8890da..cbc7c562477f 100644
--- a/drivers/usb/dwc2/core.c
+++ b/drivers/usb/dwc2/core.c
@@ -670,10 +670,23 @@ void dwc2_flush_tx_fifo(struct dwc2_hsotg *hsotg, const 
int num)
 
        dev_vdbg(hsotg->dev, "Flush Tx FIFO %d\n", num);
 
+       /* Wait for AHB master IDLE state */
+       do {
+               udelay(1);
+               greset = dwc2_readl(hsotg->regs + GRSTCTL);
+               if (++count > 10000) {
+                       dev_warn(hsotg->dev,
+                                "%s() HANG! AHB Idle GRSTCTL=%0x\n",
+                                __func__, greset);
+                       return;
+               }
+       } while (!(greset & GRSTCTL_AHBIDLE));
+
        greset = GRSTCTL_TXFFLSH;
        greset |= num << GRSTCTL_TXFNUM_SHIFT & GRSTCTL_TXFNUM_MASK;
        dwc2_writel(greset, hsotg->regs + GRSTCTL);
 
+       count = 0;
        do {
                greset = dwc2_readl(hsotg->regs + GRSTCTL);
                if (++count > 10000) {
@@ -702,9 +715,23 @@ void dwc2_flush_rx_fifo(struct dwc2_hsotg *hsotg)
 
        dev_vdbg(hsotg->dev, "%s()\n", __func__);
 
+       /* Wait for AHB master IDLE state */
+       do {
+               udelay(1);
+               greset = dwc2_readl(hsotg->regs + GRSTCTL);
+               if (++count > 10000) {
+                       dev_warn(hsotg->dev,
+                                "%s() HANG! AHB Idle GRSTCTL=%0x\n",
+                                __func__, greset);
+                       return;
+               }
+       } while (!(greset & GRSTCTL_AHBIDLE));
+
        greset = GRSTCTL_RXFFLSH;
        dwc2_writel(greset, hsotg->regs + GRSTCTL);
 
+       /* Wait for RxFIFO flush done */
+       count = 0;
        do {
                greset = dwc2_readl(hsotg->regs + GRSTCTL);
                if (++count > 10000) {
-- 
2.11.0

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