Re: [PATCH 0/6] mailbox: pcc: Refactor and improve initialisation and interrupt handling

[Adam Young]

I was just looking at it.  I think reposting might cause too much churn, 
when the  crux of the matter is what to do with these three functions I 
added:

extern struct pcc_mbox_chan *
pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id);
extern void pcc_mbox_free_channel(struct pcc_mbox_chan *chan);
extern
int pcc_mbox_write_to_buffer(struct pcc_mbox_chan *pchan, int len, void 
*data);
extern
int pcc_mbox_query_bytes_available(struct pcc_mbox_chan *pchan);
extern
int pcc_mbox_read_from_buffer(struct pcc_mbox_chan *pchan, int len,
                              void *data);

In my last patch I added them as EXPORT_SYMBOL_GPL.  You mentioned you 
wanted them as inline.

We can do that, but it does mean further exposing the ACPI header file.  
THe simplest is  pcc_mbox_query_bytes_available which I have posted 
below.  As you can see, it needs the struct 
acpi_pcct_ext_pcc_shared_memory  which comes from 
include/acpi/actbl2.h.  If you are OK with adding that to 
include/acpi/pcc.h  We can inline the functions in there.

These three functions are requied as a result of the direct access to 
the shared memory buffer.


int pcc_mbox_query_bytes_available(struct pcc_mbox_chan *pchan)
{
        struct acpi_pcct_ext_pcc_shared_memory pcc_header;
        struct pcc_chan_info *pinfo = pchan->mchan->con_priv;
        int data_len;
        u64 val;

        pcc_chan_reg_read(&pinfo->cmd_complete, &val);
        if (val) {
                pr_info("%s Buffer not enabled for reading", __func__);
                return -1;
        }
        memcpy_fromio(&pcc_header, pchan->shmem,
                      sizeof(pcc_header));
        data_len = pcc_header.length - sizeof(u32) + sizeof(pcc_header);
        return data_len;
}




On 1/27/26 04:29, Sudeep Holla wrote:
> On Mon, Jan 26, 2026 at 12:07:26PM -0500, Adam Young wrote:
> > On 1/12/26 11:55, Sudeep Holla wrote:
> > > On Thu, Nov 27, 2025 at 02:40:56PM +0000, Sudeep Holla wrote:
> > > > Hi Jassi,
> > > >
> > > > On Thu, Oct 16, 2025 at 08:08:14PM +0100, Sudeep Holla wrote:
> > > > > This series refines and stabilizes the PCC mailbox driver to improve
> > > > > initialisation order, interrupt handling, and completion signaling.
> > > > Are you happy to pull these patches directly from the list or do you
> > > > prefer me to send you pull request or do you want me to direct this via
> > > > ACPI/Rafael's tree. Please advice.
> > > Hi Jassi,
> > >
> > > Sorry for the nag. I did see these patches in -next as well as your
> > > v6.19 merge window pull request which didn't make it to Linus tree.
> > > However I don't see it -next any longer. Please advice if you want
> > > anything from my side so that this can be merged for v6.20/v7.0
> > I thought you had an approach you wanted to implement for the functions that
> > provided access to the Mailbox internals: you wanted to do them inline but
> > hadn't gotten to them yet.  Is that still the case?  I will resubmit mine as
> > is with -next if that is acceptable.
> Honestly, it has been a while and I have lost the context. Please post what
> you have or thinking of on top of linux-next or jassi's -next and we can start
> the discussion fresh.