| Message ID | 20241113211614.518439-1-karprzy7@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | mfd: omap-usb-tll: check clk_prepare return code | expand |
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@gmail.com> > --- > 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); > - 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()? I think we should return the error in this case. (after unpreparing the prepared clocks and clk_put()) > + } > } > > pm_runtime_put_sync(dev);
Am Tue, 19 Nov 2024 15:10:23 +0200 schrieb Roger Quadros <rogerq@kernel.org>: > 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@gmail.com> > > --- > > 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? > > - 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. 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) Regards, Andreas
On 19/11/2024 15:56, Andreas Kemnade wrote: > Am Tue, 19 Nov 2024 15:10:23 +0200 > schrieb Roger Quadros <rogerq@kernel.org>: > >> 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@gmail.com> >>> --- >>> 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. > >>> - 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) > > Regards, > Andreas
Am Tue, 19 Nov 2024 16:16:42 +0200 schrieb Roger Quadros <rogerq@kernel.org>: > On 19/11/2024 15:56, Andreas Kemnade wrote: > > Am Tue, 19 Nov 2024 15:10:23 +0200 > > schrieb Roger Quadros <rogerq@kernel.org>: > > > >> 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@gmail.com> > >>> --- > >>> 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
On Tue, 26 Nov 2024 at 23:06, Andreas Kemnade <andreas@kemnade.info> wrote: > > Am Tue, 19 Nov 2024 16:16:42 +0200 > schrieb Roger Quadros <rogerq@kernel.org>: > > > On 19/11/2024 15:56, Andreas Kemnade wrote: > > > Am Tue, 19 Nov 2024 15:10:23 +0200 > > > schrieb Roger Quadros <rogerq@kernel.org>: > > > > > >> 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@gmail.com> > > >>> --- > > >>> 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. I'm fairly new to this subsystem and I'm trying to understand the conclusion. In the end, we should add dev_err() here after clk_prepare() with appropriate handling? > > Regards, > Andreas Best regards, Karol
Am Thu, 5 Dec 2024 22:54:05 +0100 schrieb Karol P <karprzy7@gmail.com>: > On Tue, 26 Nov 2024 at 23:06, Andreas Kemnade <andreas@kemnade.info> wrote: > > > > Am Tue, 19 Nov 2024 16:16:42 +0200 > > schrieb Roger Quadros <rogerq@kernel.org>: > > > > > On 19/11/2024 15:56, Andreas Kemnade wrote: > > > > Am Tue, 19 Nov 2024 15:10:23 +0200 > > > > schrieb Roger Quadros <rogerq@kernel.org>: > > > > > > > >> 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@gmail.com> > > > >>> --- > > > >>> 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. > > I'm fairly new to this subsystem and I'm trying to understand the > conclusion. In the end, we should add dev_err() here after > clk_prepare() with appropriate handling? > we must make sure pm_runtime_put/get are paired and _put is called in any case. Looking around a bit: I think a good solution would be along this lines: https://lore.kernel.org/linux-omap/34ab5f0b78c2869cc43797a72d6a2f40d9b246f3.camel@siemens.com/T/#u using devm_clk_get_prepared() things can be simplified. Regards, Andreas
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); - 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); + } } pm_runtime_put_sync(dev);
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@gmail.com> --- drivers/mfd/omap-usb-tll.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)