[linux dev-6.6 v1] usb: chipidea: udc: enforce write to the memory.

[Paul Menzel]

Dear Tomer,


Thank you for your patch.

Am 10.07.24 um 14:41 schrieb Tomer Maimon:
> In the prime endpoint function, we need to read from qh.ptr->td.token
> to ensure that the previous write to it has indeed been committed
> to memory.

Please document the datasheet name, revision and section. If this 
actually caused user visible problems, please also document the test case.

> Signed-off-by: Tomer Maimon <tmaimon77 at gmail.com>
> ---
>   drivers/usb/chipidea/udc.c | 15 ++++++++++++---
>   1 file changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
> index 0b7bd3c643c3..0b14a1d54d59 100644
> --- a/drivers/usb/chipidea/udc.c
> +++ b/drivers/usb/chipidea/udc.c
> @@ -190,12 +190,21 @@ static int hw_ep_get_halt(struct ci_hdrc *ci, int num, int dir)
>    *
>    * This function returns an error code
>    */
> -static int hw_ep_prime(struct ci_hdrc *ci, int num, int dir, int is_ctrl)
> +static int hw_ep_prime(struct ci_hdrc *ci, struct ci_hw_ep *hwep, int num,
> +		       int dir, int is_ctrl)
>   {
>   	int n = hw_ep_bit(num, dir);
>   
>   	/* Synchronize before ep prime */
>   	wmb();
> +	
> +	/*
> +	 * We add the read from qh.ptr->td.token to make sure the previous
> +	 * write to it indeed got into the mamory so when we prime the DMA

m*e*mory

> +	 * will read the updated data
> +	 */
> +	if (hwep->qh.ptr->td.token & 0x80000000)
> +		pr_info("%s(): hwep->qh.ptr->td.token=%08x\n", __func__, hwep->qh.ptr->td.token);
>   
>   	if (is_ctrl && dir == RX && hw_read(ci, OP_ENDPTSETUPSTAT, BIT(num)))
>   		return -EAGAIN;
> @@ -632,7 +641,7 @@ static int _hardware_enqueue(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq)
>   		hwep->qh.ptr->cap |= cpu_to_le32(mul << __ffs(QH_MULT));
>   	}
>   
> -	ret = hw_ep_prime(ci, hwep->num, hwep->dir,
> +	ret = hw_ep_prime(ci, hwep, hwep->num, hwep->dir,
>   			   hwep->type == USB_ENDPOINT_XFER_CONTROL);
>   done:
>   	return ret;
> @@ -658,7 +667,7 @@ static int reprime_dtd(struct ci_hdrc *ci, struct ci_hw_ep *hwep,
>   	hwep->qh.ptr->td.token &=
>   		cpu_to_le32(~(TD_STATUS_HALTED | TD_STATUS_ACTIVE));
>   
> -	return hw_ep_prime(ci, hwep->num, hwep->dir,
> +	return hw_ep_prime(ci, hwep, hwep->num, hwep->dir,
>   				hwep->type == USB_ENDPOINT_XFER_CONTROL);
>   }
>   


Kind regards,

Paul