USB: s3c-hsotg: Ensure FIFOs are fully flushed after layout

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@fluff.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/gadget/s3c-hsotg.c b/drivers/usb/gadget/s3c-hsotg.c
index 31d19e1f261d3f9b25ab6f968842682b4cb174d0..26193eceb3231d48c06e98b29a09cf9849b319f5 100644 (file)
--- 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);
 }
 
 /**