[PATCH 10/15] USB: s3c-hsotg: Ensure FIFOs are fully flushed after layout

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Ben Dooks <ben-linux@xxxxxxxxx>

According to the design guide, if the FIFO layout is changed, then the
FIFOs must be flushed to ensure all FIFO pointers are correct.

Signed-off-by: Ben Dooks <ben-linux@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
 drivers/usb/gadget/s3c-hsotg.c |   26 ++++++++++++++++++++++++++
 1 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/drivers/usb/gadget/s3c-hsotg.c b/drivers/usb/gadget/s3c-hsotg.c
index 31d19e1..26193ec 100644
--- a/drivers/usb/gadget/s3c-hsotg.c
+++ b/drivers/usb/gadget/s3c-hsotg.c
@@ -300,6 +300,7 @@ static void s3c_hsotg_init_fifo(struct s3c_hsotg *hsotg)
 	unsigned int ep;
 	unsigned int addr;
 	unsigned int size;
+	int timeout;
 	u32 val;
 
 	/* the ryu 2.6.24 release ahs
@@ -335,6 +336,31 @@ static void s3c_hsotg_init_fifo(struct s3c_hsotg *hsotg)
 
 		writel(val, hsotg->regs + S3C_DPTXFSIZn(ep));
 	}
+
+	/* according to p428 of the design guide, we need to ensure that
+	 * all fifos are flushed before continuing */
+
+	writel(S3C_GRSTCTL_TxFNum(0x10) | S3C_GRSTCTL_TxFFlsh |
+	       S3C_GRSTCTL_RxFFlsh, hsotg->regs + S3C_GRSTCTL);
+
+	/* wait until the fifos are both flushed */
+	timeout = 100;
+	while (1) {
+		val = readl(hsotg->regs + S3C_GRSTCTL);
+
+		if ((val & (S3C_GRSTCTL_TxFFlsh | S3C_GRSTCTL_RxFFlsh)) == 0)
+			break;
+
+		if (--timeout == 0) {
+			dev_err(hsotg->dev,
+				"%s: timeout flushing fifos (GRSTCTL=%08x)\n",
+				__func__, val);
+		}
+
+		udelay(1);
+	}
+
+	dev_dbg(hsotg->dev, "FIFOs reset, timeout at %d\n", timeout);
 }
 
 /**
-- 
1.7.1

--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux Media]     [Linux Input]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Old Linux USB Devel Archive]

  Powered by Linux