From ben-linux@fluff.org Tue Jun 1 13:41:17 2010 From: Ben Dooks Date: Tue, 25 May 2010 05:36:52 +0100 Subject: USB: s3c-hsotg: Ensure FIFOs are fully flushed after layout To: linux-samsung-soc@vger.kernel.org, linux-usb@vger.kernel.org Cc: Ben Dooks Message-ID: <1274762213-3404-6-git-send-email-ben-linux@fluff.org> 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 Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/s3c-hsotg.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) --- 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 s 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 s 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); } /**