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Date:   Fri, 16 Apr 2021 16:47:30 +0400
In-Reply-To: <cover.1618464534.git.Arthur.Petrosyan@synopsys.com>
References: <cover.1618464534.git.Arthur.Petrosyan@synopsys.com>
From:   Artur Petrosyan <Arthur.Petrosyan@synopsys.com>
Subject: [PATCH v2 06/15] usb: dwc2: Clear fifo_map when resetting core.
To:     Felipe Balbi <balbi@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     John Youn <John.Youn@synopsys.com>,
        Artur Petrosyan <Arthur.Petrosyan@synopsys.com>,
        Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>
Message-Id: <20210416124731.C500AA005D@mailhost.synopsys.com>
Precedence: bulk

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