linux-kernel - [PATCH] usb: dwc2: hcd: Fix host channel halt flow

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Date:   Wed, 6 Dec 2017 18:58:52 +0400
From:   Minas Harutyunyan <Minas.Harutyunyan@...opsys.com>
To:     John Youn <John.Youn@...opsys.com>,
        Felipe Balbi <balbi@...nel.org>,
        "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
        <linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC:     Minas Harutyunyan <Minas.Harutyunyan@...opsys.com>
Subject: [PATCH] usb: dwc2: hcd: Fix host channel halt flow

According databook in Buffer and External DMA mode
non-split periodic channels can't be halted.

Signed-off-by: Minas Harutyunyan <hminas@...opsys.com>
---
 drivers/usb/dwc2/hcd.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index 614bb9603def..987122497408 100644
--- a/drivers/usb/dwc2/hcd.c
+++ b/drivers/usb/dwc2/hcd.c
@@ -985,6 +985,25 @@ void dwc2_hc_halt(struct dwc2_hsotg *hsotg, struct dwc2_host_chan *chan,
 
 	if (dbg_hc(chan))
 		dev_vdbg(hsotg->dev, "%s()\n", __func__);
+
+	/*
+	 * In buffer DMA or external DMA mode channel can't be halted
+	 * for non-split periodic channels. At the end of the next
+	 * uframe/frame (in the worst case), the core generates a channel
+	 * halted and disables the channel automatically.
+	 */
+	if ((hsotg->core_params->dma_enable > 0 &&
+	     hsotg->core_params->dma_desc_enable <= 0) ||
+	     hsotg->hw_params.arch == GHWCFG2_EXT_DMA_ARCH) {
+		if (!chan->do_split &&
+		    (chan->ep_type == USB_ENDPOINT_XFER_ISOC ||
+		     chan->ep_type == USB_ENDPOINT_XFER_INT)) {
+			dev_err(hsotg->dev, "%s() Channel can't be halted\n",
+				__func__);
+			return;
+		}
+	}
+
 	if (halt_status == DWC2_HC_XFER_NO_HALT_STATUS)
 		dev_err(hsotg->dev, "!!! halt_status = %d !!!\n", halt_status);
 
-- 
2.11.0