Re: [PATCH] net/imx_fec: Updating the IMX_FEC IP to support loopback mode.

[Jason Wang <jasowang@redhat.com>]

On 2019/11/30 上午12:04, Philippe Mathieu-Daudé wrote:
> On Fri, Nov 29, 2019 at 4:59 PM Wasim, Bilal <Bilal_Wasim@mentor.com> wrote:
>> Thanks for the pointers philippe.. Is the patch okay to be merged without it or do I need to do a re-submission with the updated username ?
> If there are no review comments on your patch, I think the maintainer
> taking your patch can fix this details directly, no need to resend.
>
>> -----Original Message-----
>> From: Philippe Mathieu-Daudé [mailto:philmd@redhat.com]
>> Sent: Friday, November 29, 2019 8:38 PM
>> To: bilalwasim676@gmail.com; qemu-devel@nongnu.org
>> Cc: peter.maydell@linaro.org; aa1ronham@gmail.com; jcd@tribudubois.net; qemu-arm@nongnu.org; Wasim, Bilal <Bilal_Wasim@mentor.com>; linux@roeck-us.net; Jason Wang <jasowang@redhat.com>
>> Subject: Re: [PATCH] net/imx_fec: Updating the IMX_FEC IP to support loopback mode.
>>
>> Hi Bilal,
>>
>> Cc'ing Jason, the maintainer of network devices.
>>
>> On 11/29/19 4:05 PM, bilalwasim676@gmail.com wrote:
>>> From: bwasim <bilal_wasim@mentor.com>
>> Your git setup misses your 'user.name', you could fix it running:
>>
>>     git config user.name "Bilal Wasim"
>>
>> (eventually with the --global option).
>>
>> The patch looks good otherwise.
>>
>> Thanks!


Applied with the fix for user.name.

Thanks


>>
>>> Loopback mode only works when specific conditions (as dictated by the
>>> IP guide) are met, i.e. the MII_MODE is set and the RMII_MODE is
>>> cleared. If not, we simply send the packet on the output queue (for TX
>>> to the host network). Tested by running a custom RTOS and TXing a ton
>>> of packets. The same packets were received on the RX side..
>>>
>>> Signed-off-by: Bilal Wasim <bilal_wasim@mentor.com>
>>> ---
>>>    hw/net/imx_fec.c | 27 +++++++++++++++++++++++++--
>>>    1 file changed, 25 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/hw/net/imx_fec.c b/hw/net/imx_fec.c index
>>> bd99236864..c51e7f7363 100644
>>> --- a/hw/net/imx_fec.c
>>> +++ b/hw/net/imx_fec.c
>>> @@ -256,6 +256,29 @@ static const VMStateDescription vmstate_imx_eth =
>>> {
>>>
>>>    static void imx_eth_update(IMXFECState *s);
>>>
>>> +/*
>>> + * Function to check if the MAC is configured to run in loopback mode.
>>> + * If so, invoke the "receive" routine.
>>> + * Else write to the output.
>>> + * */
>>> +static void send_pkt(IMXFECState *s, uint8_t *frame, int frame_size)
>>> +{
>>> +    NetClientState *nc = qemu_get_queue(s->nic);
>>> +
>>> +    /*
>>> +     * Loopback or Normal mode ?
>>> +     * Per the FEC Manual: If loopback is enabled, the MII_MODE
>>> +     * should be SET and the RMII_MODE should be cleared. Loopback
>>> +     * will only work if this criterion is met. If not met,
>>> +     * we will send the frame on the output queue. */
>>> +    if ((s->regs[ENET_RCR] & ENET_RCR_LOOP) && (s->regs[ENET_RCR] & ENET_RCR_MII_MODE)
>>> +            && !(s->regs[ENET_RCR] & ENET_RCR_RMII_MODE)) {
>>> +        nc->info->receive(nc, frame, frame_size);
>>> +    } else {
>>> +        qemu_send_packet(nc, frame, frame_size);
>>> +    }
>>> +}
>>> +
>>>    /*
>>>     * The MII phy could raise a GPIO to the processor which in turn
>>>     * could be handled as an interrpt by the OS.
>>> @@ -488,7 +511,7 @@ static void imx_fec_do_tx(IMXFECState *s)
>>>            frame_size += len;
>>>            if (bd.flags & ENET_BD_L) {
>>>                /* Last buffer in frame.  */
>>> -            qemu_send_packet(qemu_get_queue(s->nic), s->frame, frame_size);
>>> +            send_pkt(s, (uint8_t *)&s->frame, frame_size);
>>>                ptr = s->frame;
>>>                frame_size = 0;
>>>                s->regs[ENET_EIR] |= ENET_INT_TXF; @@ -586,7 +609,7 @@
>>> static void imx_enet_do_tx(IMXFECState *s, uint32_t index)
>>>                }
>>>                /* Last buffer in frame.  */
>>>
>>> -            qemu_send_packet(qemu_get_queue(s->nic), s->frame, frame_size);
>>> +            send_pkt(s, (uint8_t *)&s->frame, frame_size);
>>>                ptr = s->frame;
>>>
>>>                frame_size = 0;
>>>