Hi Dmitry,

Thanks for your comments,

On Tue, Sep 24, 2024 at 12:16:27PM GMT, Maxime Ripard wrote:

quoted

On Tue, Sep 24, 2024 at 03:36:49PM GMT, Sandor Yu wrote:

quoted

+static int cdns_mhdp8501_read_hpd(struct cdns_mhdp8501_device
+*mhdp) {
+   u8 status;
+   int ret;
+
+   mutex_lock(&mhdp_mailbox_mutex);
+
+   ret = cdns_mhdp_mailbox_send(&mhdp->base,

MB_MODULE_ID_GENERAL,

quoted

quoted

+                                GENERAL_GET_HPD_STATE, 0,

NULL);

quoted

quoted

+   if (ret)
+           goto err_get_hpd;
+
+   ret = cdns_mhdp_mailbox_recv_header(&mhdp->base,

MB_MODULE_ID_GENERAL,

quoted

quoted

+                                       GENERAL_GET_HPD_STATE,
+                                       sizeof(status));
+   if (ret)
+           goto err_get_hpd;
+
+   ret = cdns_mhdp_mailbox_recv_data(&mhdp->base, &status,

sizeof(status));

quoted

quoted

+   if (ret)
+           goto err_get_hpd;
+
+   mutex_unlock(&mhdp_mailbox_mutex);

That's better I guess, but it's still not a good API design. If you
can't have concurrent accesses, then cdns_mhdp_mailbox_send et al.
should take the mutex themselves.

I think that a proper API might be:

int cdns_mhdp_mailbox_send_recv(struct cdns_mhdp_device *mhdp,
                        u8 module_id, u8 opcode,
                        u16 size, const u8 *message,
                        u16 buf_size, u8 *buf);

Internally it should take the lock, exchange the data, then return.

Thank you for your great suggestion. It seems like this should be able to solve the current problem.
I need to check each existing FW access functions one by one to see if they can all work under this API function.

B.R
Sandor

--
With best wishes
Dmitry