On Sun, Jan 12, 2025 at 09:48:41PM +0100, Marek Vasut wrote:
> On 1/10/25 8:43 AM, Varadarajan Narayanan wrote:
> > dwc3_core_init loops 'timeout' times to check if the IP block is out
> > of reset using 'while (timeout--)'. If there is some issue and
> > the block doesn't come out of reset, the loop will run till
> > 'timeout' becomes zero and the post decrement operator would set
> > timeout to 0xffffffff. Though the IP block is not out reset, the
> > subsequent if check 'if !timeout' would fail as timeout is not
> > equal to zero and the function proceeds with the initialization.
> >
> > Make this a pre decrement to address this.
> >
> > Signed-off-by: Varadarajan Narayanan <quic_var...@quicinc.com>
> Does the following patch work too ? It removes all the fragile open-coded
> polling
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index a35b8c2f646..7e7017d4be7 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -29,6 +29,7 @@
> #include <linux/usb/ch9.h>
> #include <linux/usb/gadget.h>
> #include <linux/bitfield.h>
> +#include <linux/iopoll.h>
> #include <linux/math64.h>
> #include <linux/time.h>
>
> @@ -587,7 +588,6 @@ static void dwc3_set_incr_burst_type(struct dwc3 *dwc)
> */
> static int dwc3_core_init(struct dwc3 *dwc)
> {
> - unsigned long timeout;
> u32 hwparams4 = dwc->hwparams.hwparams4;
> u32 reg;
> int ret;
> @@ -610,17 +610,12 @@ static int dwc3_core_init(struct dwc3 *dwc)
> }
>
> /* issue device SoftReset too */
> - timeout = 5000;
> dwc3_writel(dwc->regs, DWC3_DCTL, DWC3_DCTL_CSFTRST);
> - while (timeout--) {
> - reg = dwc3_readl(dwc->regs, DWC3_DCTL);
> - if (!(reg & DWC3_DCTL_CSFTRST))
> - break;
> - };
> -
> - if (!timeout) {
> + ret = read_poll_timeout(dwc3_readl, reg,
> + !(reg & DWC3_DCTL_CSFTRST),
> + 1, 5000, dwc->regs, DWC3_DCTL);
> + if (ret) {
> dev_err(dwc->dev, "Reset Timed Out\n");
> - ret = -ETIMEDOUT;
> goto err0;
> }
This worked too.
Tested-By: Varadarajan Narayanan <quic_var...@quicinc.com>
Thanks
Varada
