On Tue, Aug 26, 2025 at 02:39:07PM +0200, Andrew Lunn wrote:
> > Yes. It is not safe, so I 'must wait_event_timeout before free cookie'....
> > But is there a safe way to do it?
> > Maybe:
> > ->allocate cookie
> > -> map it to an unique id
> > ->set the id to req->cookie
> > ->receive response and check id valid? Then access cookie?
>
> This is part of why adding cookies in a separate patch with a good
> commit message is important.
>
> Please take a step back. What is the big picture? Why do you need a
> cookie? What is it used for? If you describe what your requirements
> are, we might be able to suggest a better solution, or point you at a
> driver you can copy code from.
>
> Andrew
>
I try to explain the it:
driver-->fw, we has two types request:
1. without response, such as mucse_mbx_ifinsmod
2. with response, such as mucse_fw_get_macaddr
fw --> driver, we has one types request:
1. link status (link speed, duplex, pause status...)
fw tiggers irq when it sends response or request.
In order to handle link status timely, we do an irqhandle like this:
static int rnpgbe_rcv_msg_from_fw(struct mucse *mucse)
{
u32 msgbuf[MUCSE_FW_MAILBOX_WORDS];
struct mucse_hw *hw = &mucse->hw;
struct mbx_fw_cmd_reply *reply;
int retval;
/* read mbx data out */
retval = mucse_read_mbx(hw, msgbuf, MUCSE_FW_MAILBOX_WORDS);
if (retval)
return retval;
reply = (struct mbx_fw_cmd_reply *)msgbuf;
/* judge request or response */
if (le16_to_cpu(reply->flags) & FLAGS_DD) {
/* if it is a response, call wake_up(cookie) */
return rnpgbe_mbx_fw_reply_handler(mucse,
(struct mbx_fw_cmd_reply *)msgbuf);
} else {
/* if it is a request, handle link status */
return rnpgbe_mbx_fw_req_handler(mucse,
(struct mbx_fw_cmd_req *)msgbuf);
}
}
And driver requests with response is bellow 'without' irqhandle:
static int mucse_fw_send_cmd_wait(struct mucse_hw *hw,
struct mbx_fw_cmd_req *req,
struct mbx_fw_cmd_reply *reply)
{
...
mucse_write_posted_mbx(hw, (u32 *)req, len);
...
/* but as irqhandle be added, mbx data is read out in the
* handler, mucse_read_posted_mbx cannot read anything */
mucse_read_posted_mbx(hw, (u32 *)reply, sizeof(*reply));
}
To solve mucse_read_posted_mbx cannot read data with irq, we add 'cookie'.
After mucse_write_posted_mbx, call wait_event_timeout. wake_up is called
in irqhandle.
Thanks for your feedback.
