Am Tue, 19 Nov 2024 16:16:42 +0200
schrieb Roger Quadros <rogerq@xxxxxxxxxx>:
> On 19/11/2024 15:56, Andreas Kemnade wrote:
> > Am Tue, 19 Nov 2024 15:10:23 +0200
> > schrieb Roger Quadros <rogerq@xxxxxxxxxx>:
> >
> >> Hi,
> >>
> >> On 13/11/2024 23:16, Karol Przybylski wrote:
> >>> clk_prepare() is called in usbtll_omap_probe to fill clk array.
> >>> Return code is not checked, leaving possible error condition unhandled.
> >>>
> >>> Added variable to hold return value from clk_prepare() and dev_dbg statement
> >>> when it's not successful.
> >>>
> >>> Found in coverity scan, CID 1594680
> >>>
> >>> Signed-off-by: Karol Przybylski <karprzy7@xxxxxxxxx>
> >>> ---
> >>> drivers/mfd/omap-usb-tll.c | 11 +++++++----
> >>> 1 file changed, 7 insertions(+), 4 deletions(-)
> >>>
> >>> diff --git a/drivers/mfd/omap-usb-tll.c b/drivers/mfd/omap-usb-tll.c
> >>> index 0f7fdb99c809..2e9319ee1b74 100644
> >>> --- a/drivers/mfd/omap-usb-tll.c
> >>> +++ b/drivers/mfd/omap-usb-tll.c
> >>> @@ -202,7 +202,7 @@ static int usbtll_omap_probe(struct platform_device *pdev)
> >>> struct device *dev = &pdev->dev;
> >>> struct usbtll_omap *tll;
> >>> void __iomem *base;
> >>> - int i, nch, ver;
> >>> + int i, nch, ver, err;
> >>>
> >>> dev_dbg(dev, "starting TI HSUSB TLL Controller\n");
> >>>
> >>> @@ -248,10 +248,13 @@ static int usbtll_omap_probe(struct platform_device *pdev)
> >>> "usb_tll_hs_usb_ch%d_clk", i);
> >>> tll->ch_clk[i] = clk_get(dev, clkname);
> >>>
> >>> - if (IS_ERR(tll->ch_clk[i]))
> >>> + if (IS_ERR(tll->ch_clk[i])) {
> >>> dev_dbg(dev, "can't get clock : %s\n", clkname);
> >
> > if you want dev_err() later, then why not here?
>
> Because clk is optional. If it is not there then we should not complain.
> But if it is there then it needs to be enabled successfully.
>
I guess you mean *prepared*, the clock is enabled later (with error
checking). But your reasoning makes sense.
> >
> >>> - else
> >>> - clk_prepare(tll->ch_clk[i]);
> >>> + } else {
> >>> + err = clk_prepare(tll->ch_clk[i]);
> >>> + if (err)
> >>> + dev_dbg(dev, "clock prepare error for: %s\n", clkname);
> >>
> >> dev_err()?
> >>
> > So why do you want a different return handling here? (I doubt there is
> > any clock having a real prepare() involved here)
> >
> > As said in an earlier incarnation of this patch, the real question is
> > whether having partial clocks available is a valid operating scenario.
> > If yes, then the error should be ignored. If no, then bailing out early
> > is a good idea.
>
> In the DT binding, clocks is optional. So if it doesn't exist it is not
> an error condition.
>
> >
> > clk_prepare() errors are catched by failing clk_enable() later,
> > ch_clk[i] is checked later, too.
> >
> >> I think we should return the error in this case.
> >> (after unpreparing the prepared clocks and clk_put())
> >>
> > and pm_runtime_put_sync(dev)
which can probably be done before dealing with the clocks. It is only
needed for the register access.
Regards,
Andreas
