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Message-ID: <OSAPR01MB3683A8CE38F900DC0CA5D472D8240@OSAPR01MB3683.jpnprd01.prod.outlook.com>
Date: Fri, 11 Sep 2020 04:57:52 +0000
From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
To: Chunfeng Yun <chunfeng.yun@...iatek.com>
CC: Daniel Thompson <daniel.thompson@...aro.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Mathias Nyman <mathias.nyman@...el.com>,
Felipe Balbi <balbi@...nel.org>,
Matthias Brugger <matthias.bgg@...il.com>,
Douglas Anderson <dianders@...omium.org>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
Lee Jones <lee.jones@...aro.org>,
Sumit Garg <sumit.garg@...aro.org>,
Jann Horn <jannh@...gle.com>, Arnd Bergmann <arnd@...db.de>,
Jason Yan <yanaijie@...wei.com>,
Chuhong Yuan <hslester96@...il.com>,
"Gustavo A. R. Silva" <gustavoars@...nel.org>,
Ben Dooks <ben.dooks@...ethink.co.uk>,
Saurav Girepunje <saurav.girepunje@...il.com>,
"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-mediatek@...ts.infradead.org"
<linux-mediatek@...ts.infradead.org>,
Mathias Nyman <mathias.nyman@...ux.intel.com>
Subject: RE: [PATCH RESEND v3 04/11] usb: xhci-rcar: convert to
readl_poll_timeout_atomic()
Hi Chunfeng,
> From: Chunfeng Yun, Sent: Friday, September 11, 2020 1:13 PM
>
> On Fri, 2020-09-11 at 03:13 +0000, Yoshihiro Shimoda wrote:
> > Hi Daniel, Chunfeng,
> >
> > > From: Chunfeng Yun, Sent: Friday, September 11, 2020 11:33 AM
> > >
> > > 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@...ux.intel.com>
> > > > > Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
> > > > > Signed-off-by: Chunfeng Yun <chunfeng.yun@...iatek.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)
> How about free firmware and return error number here ? instead of break
I think clearing CTRL_ENABLE code below is needed.
And, I think this patch should not change a lot of things...
> > > > > 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;
> > > > > - 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.
> >
> > Thank you for your comment! I didn't realized this.
> >
> > > Yes, agree with you, but seems I keep its original logic unchanged.
> > > Hi Yoshihiro,
> > >
> > > What do think about Daniel's suggestion? should I fix it up?
> >
> > I think you should fix it up like below:
> >
> > if (readl_poll_timeout_atomic(regs + RCAR_USB3_DL_CTRL,
> > val, val & RCAR_USB3_DL_CTRL_FW_SUCCESS, 1, 10000) < 0)
> > retval = -ETIMEOUT; /* Overwrite retval if timeout occurred */
>
> readl_poll_timeout_atomic() only return -ETIMEOUT error number, so this
> likes what I did, doesn't fix it.
readl_poll_timeout_atomic() returns 0 if timeout doesn't happen.
So, when my suggestion code runs, the retval is not overwritten if
the readl_poll_timeout_atomic(regs + RCAR_USB3_DL_CTRL...) returns 0.
Best regards,
Yoshihiro Shimoda
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