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Date:   Tue, 13 Apr 2021 11:37:22 +0400
In-Reply-To: <cover.1618297800.git.Arthur.Petrosyan@synopsys.com>
References: <cover.1618297800.git.Arthur.Petrosyan@synopsys.com>
From:   Artur Petrosyan <Arthur.Petrosyan@synopsys.com>
Subject: [PATCH v2 11/12] usb: dwc2: Add clock gating exiting flow by system resume
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>
Message-Id: <20210413073723.BA0FEA022E@mailhost.synopsys.com>
Precedence: bulk

If not hibernation nor partial power down are supported,
port resume is done using the clock gating programming flow.

Adds a new flow of exiting clock gating when PC is
resumed.

Signed-off-by: Artur Petrosyan <Arthur.Petrosyan@synopsys.com>
---
 Changes in v2:
 - None

 drivers/usb/dwc2/hcd.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index 09dcd37b9ef8..04a1b53d65af 100644
--- a/drivers/usb/dwc2/hcd.c
+++ b/drivers/usb/dwc2/hcd.c
@@ -4445,6 +4445,28 @@ static int _dwc2_hcd_resume(struct usb_hcd *hcd)
 		break;
 	case DWC2_POWER_DOWN_PARAM_HIBERNATION:
 	case DWC2_POWER_DOWN_PARAM_NONE:
+		/*
+		 * If not hibernation nor partial power down are supported,
+		 * port resume is done using the clock gating programming flow.
+		 */
+		spin_unlock_irqrestore(&hsotg->lock, flags);
+		dwc2_host_exit_clock_gating(hsotg, 0);
+
+		/*
+		 * Initialize the Core for Host mode, as after system resume
+		 * the global interrupts are disabled.
+		 */
+		dwc2_core_init(hsotg, false);
+		dwc2_enable_global_interrupts(hsotg);
+		dwc2_hcd_reinit(hsotg);
+		spin_lock_irqsave(&hsotg->lock, flags);
+
+		/*
+		 * Set HW accessible bit before powering on the controller
+		 * since an interrupt may rise.
+		 */
+		set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
+		break;
 	default:
 		hsotg->lx_state = DWC2_L0;
 		goto unlock;
-- 
2.25.1