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    SubjectRe: [PATCH RESEND v3 04/11] usb: xhci-rcar: convert to readl_poll_timeout_atomic()
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    On Fri, 2020-09-11 at 09:34 +0100, Daniel Thompson wrote:
    > On Fri, Sep 11, 2020 at 10:33:21AM +0800, Chunfeng Yun wrote:
    > > On Thu, 2020-09-10 at 14:12 +0100, Daniel Thompson wrote:
    > > > On Thu, Sep 10, 2020 at 04:21:45PM +0800, Chunfeng Yun wrote:
    > > > > Use readl_poll_timeout_atomic() to simplify code
    > > > >
    > > > > Cc: Mathias Nyman <mathias.nyman@linux.intel.com>
    > > > > Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
    > > > > Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
    > > > > ---
    > > > > v2~v3: no changes
    > > > > ---
    > > > > drivers/usb/host/xhci-rcar.c | 43 ++++++++++++-------------------------------
    > > > > 1 file changed, 12 insertions(+), 31 deletions(-)
    > > > >
    > > > > diff --git a/drivers/usb/host/xhci-rcar.c b/drivers/usb/host/xhci-rcar.c
    > > > > index c1025d3..74f836f 100644
    > > > > --- a/drivers/usb/host/xhci-rcar.c
    > > > > +++ b/drivers/usb/host/xhci-rcar.c
    > > > > @@ -6,6 +6,7 @@
    > > > > */
    > > > >
    > > > > #include <linux/firmware.h>
    > > > > +#include <linux/iopoll.h>
    > > > > #include <linux/module.h>
    > > > > #include <linux/platform_device.h>
    > > > > #include <linux/of.h>
    > > > > @@ -127,8 +128,7 @@ static int xhci_rcar_download_firmware(struct usb_hcd *hcd)
    > > > > void __iomem *regs = hcd->regs;
    > > > > struct xhci_plat_priv *priv = hcd_to_xhci_priv(hcd);
    > > > > const struct firmware *fw;
    > > > > - int retval, index, j, time;
    > > > > - int timeout = 10000;
    > > > > + int retval, index, j;
    > > > > u32 data, val, temp;
    > > > > u32 quirks = 0;
    > > > > const struct soc_device_attribute *attr;
    > > > > @@ -166,32 +166,19 @@ static int xhci_rcar_download_firmware(struct usb_hcd *hcd)
    > > > > temp |= RCAR_USB3_DL_CTRL_FW_SET_DATA0;
    > > > > writel(temp, regs + RCAR_USB3_DL_CTRL);
    > > > >
    > > > > - for (time = 0; time < timeout; time++) {
    > > > > - val = readl(regs + RCAR_USB3_DL_CTRL);
    > > > > - if ((val & RCAR_USB3_DL_CTRL_FW_SET_DATA0) == 0)
    > > > > - break;
    > > > > - udelay(1);
    > > > > - }
    > > > > - if (time == timeout) {
    > > > > - retval = -ETIMEDOUT;
    > > > > + retval = readl_poll_timeout_atomic(regs + RCAR_USB3_DL_CTRL,
    > > > > + val, !(val & RCAR_USB3_DL_CTRL_FW_SET_DATA0),
    > > > > + 1, 10000);
    > > > > + if (retval < 0)
    > > > > break;
    > > > > - }
    > > > > }
    > > > >
    > > > > temp = readl(regs + RCAR_USB3_DL_CTRL);
    > > > > temp &= ~RCAR_USB3_DL_CTRL_ENABLE;
    > > > > writel(temp, regs + RCAR_USB3_DL_CTRL);
    > > > >
    > > > > - for (time = 0; time < timeout; time++) {
    > > > > - val = readl(regs + RCAR_USB3_DL_CTRL);
    > > > > - if (val & RCAR_USB3_DL_CTRL_FW_SUCCESS) {
    > > > > - retval = 0;
    Here will set it 0 too

    > > > > - break;
    > > > > - }
    > > > > - udelay(1);
    > > > > - }
    > > > > - if (time == timeout)
    > > > > - retval = -ETIMEDOUT;
    > > > > + retval = readl_poll_timeout_atomic((regs + RCAR_USB3_DL_CTRL),
    > > > > + val, (val & RCAR_USB3_DL_CTRL_FW_SUCCESS), 1, 10000);
    > > >
    > > > Directly assigning to retval at this point will clobber a previous
    > > > -ETIMEDOUT error.
    > > >
    > > > In other words if there is a timeout waiting for FW_SET_DATA0, but not for
    > > > DW_SUCCESS, then we will return the wrong return value.
    > >
    > > Yes, agree with you, but seems I keep its original logic unchanged.
    >
    > I disagree.
    >
    > Your patch does not preserve the original logic. Your patch explicitly
    > sets retval to zero if the second loop succeeds. The original code does
    > not do this. As a result there is a change of return code for one of the
    > error paths.
    >
    >
    > Daniel.

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