| Message ID | 20220511183210.5248-4-prabhakar.mahadev-lad.rj@bp.renesas.com |
|---|---|
| State | New |
| Headers | show |
| Series | Renesas RZ/G2L IRQC support | expand |
On Wed, May 11, 2022 at 8:32 PM Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> wrote: > Allow free() callback to be overridden from irq_domain_ops for > hierarchical chips. > > This allows drivers to free any resources which are allocated during > populate_parent_alloc_arg(). > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
On Wed, 11 May 2022 19:32:08 +0100, Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> wrote: > > Allow free() callback to be overridden from irq_domain_ops for > hierarchical chips. > > This allows drivers to free any resources which are allocated during > populate_parent_alloc_arg(). Do you mean more than the fwspec? I don't see this being used. There is also the question of why we need to have dynamic allocation for the fwspec itself. Why isn't that a simple stack allocation in the context of gpiochip_hierarchy_irq_domain_alloc()? M. > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> > --- > drivers/gpio/gpiolib.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c > index b7694171655c..d36c4a965efc 100644 > --- a/drivers/gpio/gpiolib.c > +++ b/drivers/gpio/gpiolib.c > @@ -1187,15 +1187,18 @@ static void gpiochip_hierarchy_setup_domain_ops(struct irq_domain_ops *ops) > ops->activate = gpiochip_irq_domain_activate; > ops->deactivate = gpiochip_irq_domain_deactivate; > ops->alloc = gpiochip_hierarchy_irq_domain_alloc; > - ops->free = irq_domain_free_irqs_common; > > /* > - * We only allow overriding the translate() function for > + * We only allow overriding the translate() and free() functions for > * hierarchical chips, and this should only be done if the user > - * really need something other than 1:1 translation. > + * really need something other than 1:1 translation for translate() > + * callback and free if user wants to free up any resources which > + * were allocated during callbacks, for example populate_parent_alloc_arg. > */ > if (!ops->translate) > ops->translate = gpiochip_hierarchy_irq_domain_translate; > + if (!ops->free) > + ops->free = irq_domain_free_irqs_common; > } > > static int gpiochip_hierarchy_add_domain(struct gpio_chip *gc) > -- > 2.25.1 > >
Hi Marc, Thank you for the review. On Thu, May 12, 2022 at 12:19 PM Marc Zyngier <maz@kernel.org> wrote: > > On Wed, 11 May 2022 19:32:08 +0100, > Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> wrote: > > > > Allow free() callback to be overridden from irq_domain_ops for > > hierarchical chips. > > > > This allows drivers to free any resources which are allocated during > > populate_parent_alloc_arg(). > > Do you mean more than the fwspec? I don't see this being used. > The free callback is used in patch 5/5 where free is overridden by rzg2l_gpio_irq_domain_free. I just gave an example there as an populate_parent_alloc_arg() In actual in the child_to_parent_hwirq callback I am using a bitmap [0] to get a free tint slot, this bitmap needs freeing up when the GPIO interrupt is released from the driver that as when overridden free callback frees the allocated tint slot so that its available for re-use. > There is also the question of why we need to have dynamic allocation > for the fwspec itself. Why isn't that a simple stack allocation in the > context of gpiochip_hierarchy_irq_domain_alloc()? > you mean gpio core itself should handle the fwspec allocation/freeing? [0] https://patchwork.kernel.org/project/linux-renesas-soc/patch/20220511183210.5248-6-prabhakar.mahadev-lad.rj@bp.renesas.com/ Cheers, Prabhakar > M. > > > > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> > > --- > > drivers/gpio/gpiolib.c | 9 ++++++--- > > 1 file changed, 6 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c > > index b7694171655c..d36c4a965efc 100644 > > --- a/drivers/gpio/gpiolib.c > > +++ b/drivers/gpio/gpiolib.c > > @@ -1187,15 +1187,18 @@ static void gpiochip_hierarchy_setup_domain_ops(struct irq_domain_ops *ops) > > ops->activate = gpiochip_irq_domain_activate; > > ops->deactivate = gpiochip_irq_domain_deactivate; > > ops->alloc = gpiochip_hierarchy_irq_domain_alloc; > > - ops->free = irq_domain_free_irqs_common; > > > > /* > > - * We only allow overriding the translate() function for > > + * We only allow overriding the translate() and free() functions for > > * hierarchical chips, and this should only be done if the user > > - * really need something other than 1:1 translation. > > + * really need something other than 1:1 translation for translate() > > + * callback and free if user wants to free up any resources which > > + * were allocated during callbacks, for example populate_parent_alloc_arg. > > */ > > if (!ops->translate) > > ops->translate = gpiochip_hierarchy_irq_domain_translate; > > + if (!ops->free) > > + ops->free = irq_domain_free_irqs_common; > > } > > > > static int gpiochip_hierarchy_add_domain(struct gpio_chip *gc) > > -- > > 2.25.1 > > > > > > -- > Without deviation from the norm, progress is not possible.
On Thu, 12 May 2022 13:48:53 +0100, "Lad, Prabhakar" <prabhakar.csengg@gmail.com> wrote: > > Hi Marc, > > Thank you for the review. > > On Thu, May 12, 2022 at 12:19 PM Marc Zyngier <maz@kernel.org> wrote: > > > > On Wed, 11 May 2022 19:32:08 +0100, > > Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> wrote: > > > > > > Allow free() callback to be overridden from irq_domain_ops for > > > hierarchical chips. > > > > > > This allows drivers to free any resources which are allocated during > > > populate_parent_alloc_arg(). > > > > Do you mean more than the fwspec? I don't see this being used. > > > The free callback is used in patch 5/5 where free is overridden by > rzg2l_gpio_irq_domain_free. I just gave an example there as an > populate_parent_alloc_arg() In actual in the child_to_parent_hwirq > callback I am using a bitmap [0] to get a free tint slot, this bitmap > needs freeing up when the GPIO interrupt is released from the driver > that as when overridden free callback frees the allocated tint slot so > that its available for re-use. Right, so that's actually a different life-cycle, and the whole populate_parent_alloc_arg() is a red herring. What you want is to free resources that have been allocated via some other paths. It'd be good if your commit message actually reflected this instead of using an example that doesn't actually exist. > > > There is also the question of why we need to have dynamic allocation > > for the fwspec itself. Why isn't that a simple stack allocation in the > > context of gpiochip_hierarchy_irq_domain_alloc()? > > > you mean gpio core itself should handle the fwspec > allocation/freeing? Yes. The only reason we resort to dynamic allocation is because ThunderX is using MSI-based GPIOs, and thus doesn't use a fwspec (no firmware is involved here). If we had a union of the two types, we could just have a stack variable, and pass that along, completely sidestepping the whole dynamic allocation/freeing business. M.
Hi Marc, On Thu, May 12, 2022 at 2:24 PM Marc Zyngier <maz@kernel.org> wrote: > > On Thu, 12 May 2022 13:48:53 +0100, > "Lad, Prabhakar" <prabhakar.csengg@gmail.com> wrote: > > > > Hi Marc, > > > > Thank you for the review. > > > > On Thu, May 12, 2022 at 12:19 PM Marc Zyngier <maz@kernel.org> wrote: > > > > > > On Wed, 11 May 2022 19:32:08 +0100, > > > Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> wrote: > > > > > > > > Allow free() callback to be overridden from irq_domain_ops for > > > > hierarchical chips. > > > > > > > > This allows drivers to free any resources which are allocated during > > > > populate_parent_alloc_arg(). > > > > > > Do you mean more than the fwspec? I don't see this being used. > > > > > The free callback is used in patch 5/5 where free is overridden by > > rzg2l_gpio_irq_domain_free. I just gave an example there as an > > populate_parent_alloc_arg() In actual in the child_to_parent_hwirq > > callback I am using a bitmap [0] to get a free tint slot, this bitmap > > needs freeing up when the GPIO interrupt is released from the driver > > that as when overridden free callback frees the allocated tint slot so > > that its available for re-use. > > Right, so that's actually a different life-cycle, and the whole > populate_parent_alloc_arg() is a red herring. What you want is to free > resources that have been allocated via some other paths. It'd be good Is there any other path which I have missed where I can free up resources? > if your commit message actually reflected this instead of using an > example that doesn't actually exist. > My bad, I will update the commit message. > > > > > There is also the question of why we need to have dynamic allocation > > > for the fwspec itself. Why isn't that a simple stack allocation in the > > > context of gpiochip_hierarchy_irq_domain_alloc()? > > > > > you mean gpio core itself should handle the fwspec > > allocation/freeing? > > Yes. The only reason we resort to dynamic allocation is because > ThunderX is using MSI-based GPIOs, and thus doesn't use a fwspec (no > firmware is involved here). > I see.. > If we had a union of the two types, we could just have a stack > variable, and pass that along, completely sidestepping the whole > dynamic allocation/freeing business. > Right agreed. Cheers, Prabhakar
On Thu, 12 May 2022 14:50:05 +0100, "Lad, Prabhakar" <prabhakar.csengg@gmail.com> wrote: > > Hi Marc, > > On Thu, May 12, 2022 at 2:24 PM Marc Zyngier <maz@kernel.org> wrote: > > > > On Thu, 12 May 2022 13:48:53 +0100, > > "Lad, Prabhakar" <prabhakar.csengg@gmail.com> wrote: > > > > > > Hi Marc, > > > > > > Thank you for the review. > > > > > > On Thu, May 12, 2022 at 12:19 PM Marc Zyngier <maz@kernel.org> wrote: > > > > > > > > On Wed, 11 May 2022 19:32:08 +0100, > > > > Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> wrote: > > > > > > > > > > Allow free() callback to be overridden from irq_domain_ops for > > > > > hierarchical chips. > > > > > > > > > > This allows drivers to free any resources which are allocated during > > > > > populate_parent_alloc_arg(). > > > > > > > > Do you mean more than the fwspec? I don't see this being used. > > > > > > > The free callback is used in patch 5/5 where free is overridden by > > > rzg2l_gpio_irq_domain_free. I just gave an example there as an > > > populate_parent_alloc_arg() In actual in the child_to_parent_hwirq > > > callback I am using a bitmap [0] to get a free tint slot, this bitmap > > > needs freeing up when the GPIO interrupt is released from the driver > > > that as when overridden free callback frees the allocated tint slot so > > > that its available for re-use. > > > > Right, so that's actually a different life-cycle, and the whole > > populate_parent_alloc_arg() is a red herring. What you want is to free > > resources that have been allocated via some other paths. It'd be good > Is there any other path which I have missed where I can free up resources? No, that's the only one. It is just that usually, the alloc() callback is where you are supposed to perform... allocations. It'd be good if you could move your allocation there, as I would expect calls to child_to_parent_hwirq() to be idempotent. > > > if your commit message actually reflected this instead of using an > > example that doesn't actually exist. > > > My bad, I will update the commit message. > > > > > > > > There is also the question of why we need to have dynamic allocation > > > > for the fwspec itself. Why isn't that a simple stack allocation in the > > > > context of gpiochip_hierarchy_irq_domain_alloc()? > > > > > > > you mean gpio core itself should handle the fwspec > > > allocation/freeing? > > > > Yes. The only reason we resort to dynamic allocation is because > > ThunderX is using MSI-based GPIOs, and thus doesn't use a fwspec (no > > firmware is involved here). > > > I see.. > > > If we had a union of the two types, we could just have a stack > > variable, and pass that along, completely sidestepping the whole > > dynamic allocation/freeing business. > > > Right agreed. FWIW, I've just posted a PoC patch[1]. Thanks, M. [1] https://lore.kernel.org/r/20220512162320.2213488-1-maz@kernel.org
Hi Marc, On Thu, May 12, 2022 at 5:26 PM Marc Zyngier <maz@kernel.org> wrote: > > On Thu, 12 May 2022 14:50:05 +0100, > "Lad, Prabhakar" <prabhakar.csengg@gmail.com> wrote: > > > > Hi Marc, > > > > On Thu, May 12, 2022 at 2:24 PM Marc Zyngier <maz@kernel.org> wrote: > > > > > > On Thu, 12 May 2022 13:48:53 +0100, > > > "Lad, Prabhakar" <prabhakar.csengg@gmail.com> wrote: > > > > > > > > Hi Marc, > > > > > > > > Thank you for the review. > > > > > > > > On Thu, May 12, 2022 at 12:19 PM Marc Zyngier <maz@kernel.org> wrote: > > > > > > > > > > On Wed, 11 May 2022 19:32:08 +0100, > > > > > Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> wrote: > > > > > > > > > > > > Allow free() callback to be overridden from irq_domain_ops for > > > > > > hierarchical chips. > > > > > > > > > > > > This allows drivers to free any resources which are allocated during > > > > > > populate_parent_alloc_arg(). > > > > > > > > > > Do you mean more than the fwspec? I don't see this being used. > > > > > > > > > The free callback is used in patch 5/5 where free is overridden by > > > > rzg2l_gpio_irq_domain_free. I just gave an example there as an > > > > populate_parent_alloc_arg() In actual in the child_to_parent_hwirq > > > > callback I am using a bitmap [0] to get a free tint slot, this bitmap > > > > needs freeing up when the GPIO interrupt is released from the driver > > > > that as when overridden free callback frees the allocated tint slot so > > > > that its available for re-use. > > > > > > Right, so that's actually a different life-cycle, and the whole > > > populate_parent_alloc_arg() is a red herring. What you want is to free > > > resources that have been allocated via some other paths. It'd be good > > Is there any other path which I have missed where I can free up resources? > > No, that's the only one. It is just that usually, the alloc() > callback is where you are supposed to perform... allocations. > OK. > It'd be good if you could move your allocation there, as I would > expect calls to child_to_parent_hwirq() to be idempotent. > For now I'll go with the current implementation, as currently a an array is maintained which is tied with the tint slot and child (which is obtained from child_to_parent_hwirq) > > > > > if your commit message actually reflected this instead of using an > > > example that doesn't actually exist. > > > > > My bad, I will update the commit message. > > > > > > > > > > > There is also the question of why we need to have dynamic allocation > > > > > for the fwspec itself. Why isn't that a simple stack allocation in the > > > > > context of gpiochip_hierarchy_irq_domain_alloc()? > > > > > > > > > you mean gpio core itself should handle the fwspec > > > > allocation/freeing? > > > > > > Yes. The only reason we resort to dynamic allocation is because > > > ThunderX is using MSI-based GPIOs, and thus doesn't use a fwspec (no > > > firmware is involved here). > > > > > I see.. > > > > > If we had a union of the two types, we could just have a stack > > > variable, and pass that along, completely sidestepping the whole > > > dynamic allocation/freeing business. > > > > > Right agreed. > > FWIW, I've just posted a PoC patch[1]. > I guess I'll have to rebase my changes on top of it now ;) Cheers, Prabhakar
On Thu, 12 May 2022 18:55:38 +0100, "Lad, Prabhakar" <prabhakar.csengg@gmail.com> wrote: > > Hi Marc, > > On Thu, May 12, 2022 at 5:26 PM Marc Zyngier <maz@kernel.org> wrote: > > > > On Thu, 12 May 2022 14:50:05 +0100, > > "Lad, Prabhakar" <prabhakar.csengg@gmail.com> wrote: > > > > > > Hi Marc, > > > > > > On Thu, May 12, 2022 at 2:24 PM Marc Zyngier <maz@kernel.org> wrote: > > > > > > > > On Thu, 12 May 2022 13:48:53 +0100, > > > > "Lad, Prabhakar" <prabhakar.csengg@gmail.com> wrote: > > > > > > > > > > Hi Marc, > > > > > > > > > > Thank you for the review. > > > > > > > > > > On Thu, May 12, 2022 at 12:19 PM Marc Zyngier <maz@kernel.org> wrote: > > > > > > > > > > > > On Wed, 11 May 2022 19:32:08 +0100, > > > > > > Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> wrote: > > > > > > > > > > > > > > Allow free() callback to be overridden from irq_domain_ops for > > > > > > > hierarchical chips. > > > > > > > > > > > > > > This allows drivers to free any resources which are allocated during > > > > > > > populate_parent_alloc_arg(). > > > > > > > > > > > > Do you mean more than the fwspec? I don't see this being used. > > > > > > > > > > > The free callback is used in patch 5/5 where free is overridden by > > > > > rzg2l_gpio_irq_domain_free. I just gave an example there as an > > > > > populate_parent_alloc_arg() In actual in the child_to_parent_hwirq > > > > > callback I am using a bitmap [0] to get a free tint slot, this bitmap > > > > > needs freeing up when the GPIO interrupt is released from the driver > > > > > that as when overridden free callback frees the allocated tint slot so > > > > > that its available for re-use. > > > > > > > > Right, so that's actually a different life-cycle, and the whole > > > > populate_parent_alloc_arg() is a red herring. What you want is to free > > > > resources that have been allocated via some other paths. It'd be good > > > Is there any other path which I have missed where I can free up resources? > > > > No, that's the only one. It is just that usually, the alloc() > > callback is where you are supposed to perform... allocations. > > > OK. > > > It'd be good if you could move your allocation there, as I would > > expect calls to child_to_parent_hwirq() to be idempotent. > > > For now I'll go with the current implementation, as currently a an > array is maintained which is tied with the tint slot and child (which > is obtained from child_to_parent_hwirq) > > > > > > > > if your commit message actually reflected this instead of using an > > > > example that doesn't actually exist. > > > > > > > My bad, I will update the commit message. > > > > > > > > > > > > > > There is also the question of why we need to have dynamic allocation > > > > > > for the fwspec itself. Why isn't that a simple stack allocation in the > > > > > > context of gpiochip_hierarchy_irq_domain_alloc()? > > > > > > > > > > > you mean gpio core itself should handle the fwspec > > > > > allocation/freeing? > > > > > > > > Yes. The only reason we resort to dynamic allocation is because > > > > ThunderX is using MSI-based GPIOs, and thus doesn't use a fwspec (no > > > > firmware is involved here). > > > > > > > I see.. > > > > > > > If we had a union of the two types, we could just have a stack > > > > variable, and pass that along, completely sidestepping the whole > > > > dynamic allocation/freeing business. > > > > > > > Right agreed. > > > > FWIW, I've just posted a PoC patch[1]. > > > I guess I'll have to rebase my changes on top of it now ;) Not yet. Let's see what people say about it. M.
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index b7694171655c..d36c4a965efc 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1187,15 +1187,18 @@ static void gpiochip_hierarchy_setup_domain_ops(struct irq_domain_ops *ops) ops->activate = gpiochip_irq_domain_activate; ops->deactivate = gpiochip_irq_domain_deactivate; ops->alloc = gpiochip_hierarchy_irq_domain_alloc; - ops->free = irq_domain_free_irqs_common; /* - * We only allow overriding the translate() function for + * We only allow overriding the translate() and free() functions for * hierarchical chips, and this should only be done if the user - * really need something other than 1:1 translation. + * really need something other than 1:1 translation for translate() + * callback and free if user wants to free up any resources which + * were allocated during callbacks, for example populate_parent_alloc_arg. */ if (!ops->translate) ops->translate = gpiochip_hierarchy_irq_domain_translate; + if (!ops->free) + ops->free = irq_domain_free_irqs_common; } static int gpiochip_hierarchy_add_domain(struct gpio_chip *gc)
Allow free() callback to be overridden from irq_domain_ops for hierarchical chips. This allows drivers to free any resources which are allocated during populate_parent_alloc_arg(). Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> --- drivers/gpio/gpiolib.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)