| Message ID | 20210429134749.75157-1-ameynarkhede03@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | PCI: mediatek: Verify whether the free_ck clock is ungated or not | expand |
Can you make the subject say something at a higher level instead of just paraphrasing the C code? I'm guessing this means resume will now fail if the clock isn't turned on? On Thu, Apr 29, 2021 at 07:17:49PM +0530, Amey Narkhede wrote: > Verify that the free_ck clock is ungated on device resume > by checking return value of clk_prepare_enable(). Also the commit log -- this doesn't say anything more than the code itself. Did you find this by tripping over it? Or just by code inspection? I guess without the check, we continue on and try to resume, but accesses to PCI devices fail and maybe return ~0 data or cause machine checks or something? > Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com> > --- > drivers/pci/controller/pcie-mediatek.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c > index 23548b517..9b13214bf 100644 > --- a/drivers/pci/controller/pcie-mediatek.c > +++ b/drivers/pci/controller/pcie-mediatek.c > @@ -1154,11 +1154,14 @@ static int __maybe_unused mtk_pcie_resume_noirq(struct device *dev) > { > struct mtk_pcie *pcie = dev_get_drvdata(dev); > struct mtk_pcie_port *port, *tmp; > + int ret; > > if (list_empty(&pcie->ports)) > return 0; > > - clk_prepare_enable(pcie->free_ck); > + ret = clk_prepare_enable(pcie->free_ck); > + if (ret) > + return ret; Most callers print an error message when clk_prepare_enable() fails. > list_for_each_entry_safe(port, tmp, &pcie->ports, list) > mtk_pcie_enable_port(port); > -- > 2.31.1
On 21/04/29 05:38PM, Bjorn Helgaas wrote: > Can you make the subject say something at a higher level instead of > just paraphrasing the C code? I'm guessing this means resume will now > fail if the clock isn't turned on? > > On Thu, Apr 29, 2021 at 07:17:49PM +0530, Amey Narkhede wrote: > > Verify that the free_ck clock is ungated on device resume > > by checking return value of clk_prepare_enable(). > > Also the commit log -- this doesn't say anything more than the code > itself. Did you find this by tripping over it? Or just by code > inspection? I guess without the check, we continue on and try to > resume, but accesses to PCI devices fail and maybe return ~0 data or > cause machine checks or something? > I found this with code inspection. Sorry for the unclear commit messsage. I'll try to clarify it in v2. > > Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com> > > --- > > drivers/pci/controller/pcie-mediatek.c | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c > > index 23548b517..9b13214bf 100644 > > --- a/drivers/pci/controller/pcie-mediatek.c > > +++ b/drivers/pci/controller/pcie-mediatek.c > > @@ -1154,11 +1154,14 @@ static int __maybe_unused mtk_pcie_resume_noirq(struct device *dev) > > { > > struct mtk_pcie *pcie = dev_get_drvdata(dev); > > struct mtk_pcie_port *port, *tmp; > > + int ret; > > > > if (list_empty(&pcie->ports)) > > return 0; > > > > - clk_prepare_enable(pcie->free_ck); > > + ret = clk_prepare_enable(pcie->free_ck); > > + if (ret) > > + return ret; > > Most callers print an error message when clk_prepare_enable() fails. > [...] I'll update this in v2. Thanks, Amey
diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c index 23548b517..9b13214bf 100644 --- a/drivers/pci/controller/pcie-mediatek.c +++ b/drivers/pci/controller/pcie-mediatek.c @@ -1154,11 +1154,14 @@ static int __maybe_unused mtk_pcie_resume_noirq(struct device *dev) { struct mtk_pcie *pcie = dev_get_drvdata(dev); struct mtk_pcie_port *port, *tmp; + int ret; if (list_empty(&pcie->ports)) return 0; - clk_prepare_enable(pcie->free_ck); + ret = clk_prepare_enable(pcie->free_ck); + if (ret) + return ret; list_for_each_entry_safe(port, tmp, &pcie->ports, list) mtk_pcie_enable_port(port);
Verify that the free_ck clock is ungated on device resume by checking return value of clk_prepare_enable(). Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com> --- drivers/pci/controller/pcie-mediatek.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) -- 2.31.1