Re: [v2] PCI: tegra194: Fix debugfs directory creation when CONFIG_PCIEASPM is disabled

[Hans Zhang]

On 2025/4/7 02:10, Christophe JAILLET wrote:
> Le 06/04/2025 à 15:43, Hans Zhang a écrit :
> > Previously, the debugfs directory was unconditionally created in
> > tegra_pcie_config_rp() regardless of the CONFIG_PCIEASPM setting.
> > This led to unnecessary directory creation when ASPM support was 
> > disabled.
> >
> > Move the debugfs directory creation into init_debugfs() which is
> > conditionally compiled based on CONFIG_PCIEASPM. This ensures:
> > - The directory is only created when ASPM-related debugfs entries are
> >    needed.
> > - Proper error handling for directory creation failures.
> > - Avoids cluttering debugfs with empty directories when ASPM is disabled.
> >
> > Signed-off-by: Hans Zhang <18255117159-9Onoh4P/yGk@xxxxxxxxxxxxxxxx>
> > ---
> > Changes since v1:
> > https://lore.kernel.org/linux-pci/20250405145459.26800-1-18255117159-9Onoh4P/yGk@xxxxxxxxxxxxxxxx
> >
> > - The first version was committed incorrectly because the judgment
> >    parameter in "debugfs_remove_recursive" was not noticed.
> > ---
> >   drivers/pci/controller/dwc/pcie-tegra194.c | 27 +++++++++++++---------
> >   1 file changed, 16 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c 
> > b/drivers/pci/controller/dwc/pcie-tegra194.c
> > index 5103995cd6c7..f048b2342af4 100644
> > --- a/drivers/pci/controller/dwc/pcie-tegra194.c
> > +++ b/drivers/pci/controller/dwc/pcie-tegra194.c
> > @@ -711,16 +711,27 @@ static void init_host_aspm(struct tegra_pcie_dw 
> > *pcie)
> >       dw_pcie_writel_dbi(pci, PCIE_PORT_AFR, val);
> >   }
> > -static void init_debugfs(struct tegra_pcie_dw *pcie)
> > +static int init_debugfs(struct tegra_pcie_dw *pcie)
>
> I would keep it a void function.
> If devm_kasprintf() fails, which is unlikely, then the module should 
> still work correctly. So just a return; should be fine IMHO.
>
> Usually, errors related to debugfs are silently ignored as is does not 
> prevent this to work.

Hi Christophe,

Thanks your for reply. Will change.

Best regards,
Hans

> CJ
>
> >   {
> > -    debugfs_create_devm_seqfile(pcie->dev, "aspm_state_cnt", 
> > pcie->debugfs,
> > +    struct device *dev = pcie->dev;
> > +    char *name;
> > +
> > +    name = devm_kasprintf(dev, GFP_KERNEL, "%pOFP", dev->of_node);
> > +    if (!name)
> > +        return -ENOMEM;
> > +
> > +    pcie->debugfs = debugfs_create_dir(name, NULL);
> > +
> > +    debugfs_create_devm_seqfile(dev, "aspm_state_cnt", pcie->debugfs,
> >                       aspm_state_cnt);
> > +
> > +    return 0;
> >   }
> >   #else
> >   static inline void disable_aspm_l12(struct tegra_pcie_dw *pcie) { 
> > return; }
> >   static inline void disable_aspm_l11(struct tegra_pcie_dw *pcie) { 
> > return; }
> >   static inline void init_host_aspm(struct tegra_pcie_dw *pcie) { 
> > return; }
> > -static inline void init_debugfs(struct tegra_pcie_dw *pcie) { return; }
> > +static inline int init_debugfs(struct tegra_pcie_dw *pcie) { return 0; }
> >   #endif
> >   static void tegra_pcie_enable_system_interrupts(struct dw_pcie_rp *pp)
> > @@ -1634,7 +1645,6 @@ static void tegra_pcie_deinit_controller(struct 
> > tegra_pcie_dw *pcie)
> >   static int tegra_pcie_config_rp(struct tegra_pcie_dw *pcie)
> >   {
> >       struct device *dev = pcie->dev;
> > -    char *name;
> >       int ret;
> >       pm_runtime_enable(dev);
> > @@ -1664,14 +1674,9 @@ static int tegra_pcie_config_rp(struct 
> > tegra_pcie_dw *pcie)
> >           goto fail_host_init;
> >       }
> > -    name = devm_kasprintf(dev, GFP_KERNEL, "%pOFP", dev->of_node);
> > -    if (!name) {
> > -        ret = -ENOMEM;
> > +    ret = init_debugfs(pcie);
> > +    if (ret < 0)
> >           goto fail_host_init;
> > -    }
> > -
> > -    pcie->debugfs = debugfs_create_dir(name, NULL);
> > -    init_debugfs(pcie);
> >       return ret;
> >
> > base-commit: a8662bcd2ff152bfbc751cab20f33053d74d0963