> -----Original Message----- > From: Roger Quadros <rogerq@xxxxxxxxxx> > Sent: Tuesday, June 27, 2023 5:41 AM > To: Ravi Gunasekaran <r-gunasekaran@xxxxxx>; Frank Li <frank.li@xxxxxxx> > Cc: linux-usb@xxxxxxxxxxxxxxx; peter.chen@xxxxxxxxxx; > pawell@xxxxxxxxxxx > Subject: [EXT] Re: usb: cdns3: Onchip memory reservation for built-in > gadgets > > Caution: This is an external email. Please take care when clicking links or > opening attachments. When in doubt, report the message using the 'Report > this email' button > > > Hi, > > On 27/06/2023 15:56, Ravi Gunasekaran wrote: > > Hi, > > > > Firstly, I'm not sure if it is alright to post queries this way. > > If it is wrong, I apologize for it. Please let me know the right path/forum to > ask the questions. > > > > This is regarding the commit > > dce49449e04f usb: cdns3: allocate TX FIFO size according to composite EP > number > > > > This commit introduced cdns3_gadget_check_config() which is invoked > while binding gadget created via configfs and > > also a logic to calculate ep_buf_size (which was CDNS3_EP_BUF_SIZE = 4). > > > > But for gadgets such as g_ether, g_cdc, the checks are not performed. And > also for these legacy gadget drivers, > > memory needs to be reserved for multiple IN end points and shared > memory for OUT end points. So when ep_buf_size = 15, > > the memory reservation fails, as it exceeds total onchip memory. > > > > So I was wondering if additional checks need to done in the cadence gadget > driver or am I doing something wrong while > > loading gadgets such as g_ether. > > > > I think Ravi's concern is that. > > prior to commit dce49449e04f, priv_dev->ep_buf_size was fixed at 4. > After commit dce49449e04f, it is at 0 if check_config() is not called e.g. > in the legacy gadget cases (e.g. g_ether). > So cdns3_ep_config() fails with dev_err(priv_dev->dev, "onchip mem is full, > ep is invalid\n"). > > A potential fix might be to start with priv_dev->ep_buf_size = 4 > instead of 0 so it works for legacy gadgets as well where check_config() is not > invoked. I think it should fix at legacy driver by call usb_gadget_check_config. Assume there are a UDC controller, which only 2 endpoint. g_cdc should get failure. Best regards Frank Li > > -- > cheers, > -roger
