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Groups > linux.kernel > #1270922

[PATCH v4 07/12] usb: xhci: dbc: handle dbc-configured exit

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DbC might exit configured state in some cases (refer to 7.6.4.4 in
xHCI spec 1.1). Software needs detect and clear this situation by
clearing DCCTRL.DCR and wait until the DbC configured before read
or write oprations.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/usb/early/xhci-dbc.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/usb/early/xhci-dbc.c b/drivers/usb/early/xhci-dbc.c
index f51daa4..8a5a51f 100644
--- a/drivers/usb/early/xhci-dbc.c
+++ b/drivers/usb/early/xhci-dbc.c
@@ -1153,6 +1153,29 @@ static int xdbc_wait_until_bulk_done(struct xdbc_trb *trb, int loops)
 	return -EIO;
 }
 
+static int xdbc_wait_until_dbc_configured(void)
+{
+	int timeout = 0;
+	u32 reg;
+
+	/* Port exits configured state */
+	reg = readl(&xdbcp->xdbc_reg->control);
+	if (!(reg & CTRL_DRC))
+		return 0;
+
+	/* clear run change bit (RW1C) */
+	writel(reg | CTRL_DRC, &xdbcp->xdbc_reg->control);
+
+	do {
+		if (readl(&xdbcp->xdbc_reg->control) & CTRL_DCR)
+			return 0;
+
+		xdbc_udelay(10);
+	} while (timeout++ < XDBC_LOOPS);
+
+	return -ETIMEDOUT;
+}
+
 static int xdbc_bulk_transfer(void *data, int size, int loops, bool read)
 {
 	u64 addr;
@@ -1167,6 +1190,11 @@ static int xdbc_bulk_transfer(void *data, int size, int loops, bool read)
 		return -EINVAL;
 	}
 
+	if (xdbc_wait_until_dbc_configured()) {
+		xdbc_trace("%s: hardware not ready\n", __func__);
+		return -EPERM;
+	}
+
 	ring = (read ? &xdbcp->in_ring : &xdbcp->out_ring);
 	trb = ring->enqueue;
 	cycle = ring->cycle_state;
-- 
2.1.4

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Thread

[PATCH v4 00/12] usb: early: add support for early printk through USB3 debug port Lu Baolu <baolu.lu@linux.intel.com> - 2015-11-17 07:40 +0100
  [PATCH v4 05/12] usb: xhci: dbc: add debug buffer Lu Baolu <baolu.lu@linux.intel.com> - 2015-11-17 07:40 +0100
  [PATCH v4 09/12] x86: early_printk: add USB3 debug port earlyprintk support Lu Baolu <baolu.lu@linux.intel.com> - 2015-11-17 07:50 +0100
  [PATCH v4 04/12] usb: xhci: dbc: add support for Intel xHCI dbc quirk Lu Baolu <baolu.lu@linux.intel.com> - 2015-11-17 07:50 +0100
  [PATCH v4 12/12] usb: doc: add document for xHCI DbC driver Lu Baolu <baolu.lu@linux.intel.com> - 2015-11-17 07:50 +0100
  [PATCH v4 03/12] usb: xhci: dbc: probe and setup xhci debug capability Lu Baolu <baolu.lu@linux.intel.com> - 2015-11-17 07:50 +0100
  [PATCH v4 02/12] x86: fixmap: add permanent fixmap for xhci debug port Lu Baolu <baolu.lu@linux.intel.com> - 2015-11-17 07:50 +0100
  [PATCH v4 10/12] usb: xhci: dbc: add handshake between debug target and host Lu Baolu <baolu.lu@linux.intel.com> - 2015-11-17 07:50 +0100
  [PATCH v4 01/12] usb: xhci: add sysfs file for xHCI debug port Lu Baolu <baolu.lu@linux.intel.com> - 2015-11-17 07:50 +0100
    Re: [PATCH v4 01/12] usb: xhci: add sysfs file for xHCI debug port Mathias Nyman <mathias.nyman@linux.intel.com> - 2015-11-20 15:30 +0100
      Re: [PATCH v4 01/12] usb: xhci: add sysfs file for xHCI debug port Lu Baolu <baolu.lu@linux.intel.com> - 2015-11-22 04:10 +0100
  [PATCH v4 11/12] usb: serial: usb_debug: add support for dbc debug device Lu Baolu <baolu.lu@linux.intel.com> - 2015-11-17 07:50 +0100
  [PATCH v4 06/12] usb: xhci: dbc: add bulk out and bulk in interfaces Lu Baolu <baolu.lu@linux.intel.com> - 2015-11-17 07:50 +0100
  [PATCH v4 07/12] usb: xhci: dbc: handle dbc-configured exit Lu Baolu <baolu.lu@linux.intel.com> - 2015-11-17 07:50 +0100
  [PATCH v4 08/12] usb: xhci: dbc: handle endpoint stall Lu Baolu <baolu.lu@linux.intel.com> - 2015-11-17 07:50 +0100

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