Re: [PATCH v9 5/9] mailbox: add CIX mailbox driver

On Sun, Jul 13, 2025, at 19:00, Jassi Brar wrote:

On Tue, Jul 8, 2025 at 8:54 AM Guomin chen [off-list ref] wrote:
....

quoted

quoted

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+/* [0~7] Fast channel
+ * [8] doorbell base channel
+ * [9]fifo base channel
+ * [10] register base channel
+ */
+#define MBOX_FAST_IDX          7
+#define MBOX_DB_IDX            8
+#define MBOX_FIFO_IDX          9
+#define MBOX_REG_IDX           10
+#define CIX_MBOX_CHANS         11
+

if it is not really a single controller owning different channels,
maybe implement only what you currently use.

As mentioned in the previous email, a single controller can support
multiple different channels.

OK. I am not too worried about having all variants in one driver esp
when it is manageable and share the code.
Unless I am overlooking something. Arnd?

My main worry here is that the types are all quite different: while
the doorbell and fast mailboxes are what a lot of other drivers have,
the FIFO mode does not seem to be a good fit for the mailbox subsystem
but instead looks like a more generic firmware interface with variable
length messages.

For those, I think a higher-level driver with fixed data structures
passed through the hardware interface seems more appropriate.

Are there any other mailbox drivers that just use the mailbox to
tunnel variable-length messages?

     Arnd