Re: [PATCH 2/4] clk: tegra: check BPMP response return code

[Timo Alho]

Hi Jon,

On 21.09.2017 14:21, Jonathan Hunter wrote:
> On 07/09/17 10:31, Timo Alho wrote:
> > Check return code in BPMP response message(s). The typical error case
> > is when clock operation is attempted with invalid clock identifier.
> >
> > Also remove error print from call to clk_get_info() as the
> > implementation loops through range of all possible identifier, but the
> > operation is expected error out when the clock id is unused.
> >
> > Signed-off-by: Timo Alho <talho@xxxxxxxxxx>
> > ---
> >   drivers/clk/tegra/clk-bpmp.c | 15 ++++++++++-----
> >   1 file changed, 10 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/clk/tegra/clk-bpmp.c b/drivers/clk/tegra/clk-bpmp.c
> > index 638ace6..a896692 100644
> > --- a/drivers/clk/tegra/clk-bpmp.c
> > +++ b/drivers/clk/tegra/clk-bpmp.c
> > @@ -55,6 +55,7 @@ struct tegra_bpmp_clk_message {
> >   	struct {
> >   		void *data;
> >   		size_t size;
> > +		int ret;
> >   	} rx;
> >   };
> >   
> > @@ -64,6 +65,7 @@ static int tegra_bpmp_clk_transfer(struct tegra_bpmp *bpmp,
> >   	struct mrq_clk_request request;
> >   	struct tegra_bpmp_message msg;
> >   	void *req = &request;
> > +	int err;
> >   
> >   	memset(&request, 0, sizeof(request));
> >   	request.cmd_and_id = (clk->cmd << 24) | clk->id;
> > @@ -84,7 +86,13 @@ static int tegra_bpmp_clk_transfer(struct tegra_bpmp *bpmp,
> >   	msg.rx.data = clk->rx.data;
> >   	msg.rx.size = clk->rx.size;
> >   
> > -	return tegra_bpmp_transfer(bpmp, &msg);
> > +	err = tegra_bpmp_transfer(bpmp, &msg);
> > +	if (err < 0)
> > +		return err;
> > +	else if (msg.rx.ret < 0)
> > +		return -EINVAL;
>
> I assume that the error codes returned do not correlated to the Linux
> error codes here. Is that correct? If not we could just return the
> actual error code. Otherwise would it be useful to print a message with
> the bpmp error code for debug?

The error codes are not 1:1 match with Linux. Unfortunately, printing 
message for debug is not either viable as during clock probing we are 
expecting many of the calls to return -BPMP_EINVAL to indicate that 
particular clock ID is unused.

-Timo