2022-06-27 05:26:14

by Samuel Holland

Subject: [PATCH v1 2/3] irqchip/sifive-plic: Name the chip more generically

The interface for SiFive's PLIC was adopted and clarified by RISC-V as
the standard PLIC interface. Now that several PLIC implementations by
different vendors share this same interface, it is somewhat misleading
to report "SiFive PLIC" to userspace, when no SiFive hardware may be
present. This is especially the case when some implementations are
subtly incompatible with the binding and behavior of the SiFive PLIC,
yet are similar enough to share a driver.

Signed-off-by: Samuel Holland <[email protected]>
---

drivers/irqchip/irq-sifive-plic.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index bb87e4c3b88e..90515865af08 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -28,6 +28,11 @@
* The largest number supported by devices marked as 'sifive,plic-1.0.0', is
* 1024, of which device 0 is defined as non-existent by the RISC-V Privileged
* Spec.
+ *
+ * The PLIC behavior and memory map is futher formalized as an official RISC-V
+ * specification:
+ *
+ * https://github.com/riscv/riscv-plic-spec/blob/master/riscv-plic.adoc
*/

#define MAX_DEVICES 1024
@@ -177,12 +182,12 @@ static void plic_irq_eoi(struct irq_data *d)
}

static struct irq_chip plic_chip = {
- .name = "SiFive PLIC",
- .irq_mask = plic_irq_mask,
- .irq_unmask = plic_irq_unmask,
- .irq_eoi = plic_irq_eoi,
+ .name = "PLIC",
+ .irq_mask = plic_irq_mask,
+ .irq_unmask = plic_irq_unmask,
+ .irq_eoi = plic_irq_eoi,
#ifdef CONFIG_SMP
- .irq_set_affinity = plic_set_affinity,
+ .irq_set_affinity = plic_set_affinity,
#endif
};

--
2.35.1

2022-06-27 07:03:37

by Guo Ren

Subject: Re: [PATCH v1 2/3] irqchip/sifive-plic: Name the chip more generically

Reviewed-by: Guo Ren <[email protected]>

On Mon, Jun 27, 2022 at 1:13 PM Samuel Holland <[email protected]> wrote:
>
> The interface for SiFive's PLIC was adopted and clarified by RISC-V as
> the standard PLIC interface. Now that several PLIC implementations by
> different vendors share this same interface, it is somewhat misleading
> to report "SiFive PLIC" to userspace, when no SiFive hardware may be
> present. This is especially the case when some implementations are
> subtly incompatible with the binding and behavior of the SiFive PLIC,
> yet are similar enough to share a driver.
>
> Signed-off-by: Samuel Holland <[email protected]>
> ---
>
> drivers/irqchip/irq-sifive-plic.c | 15 ++++++++++-----
> 1 file changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
> index bb87e4c3b88e..90515865af08 100644
> --- a/drivers/irqchip/irq-sifive-plic.c
> +++ b/drivers/irqchip/irq-sifive-plic.c
> @@ -28,6 +28,11 @@
> * The largest number supported by devices marked as 'sifive,plic-1.0.0', is
> * 1024, of which device 0 is defined as non-existent by the RISC-V Privileged
> * Spec.
> + *
> + * The PLIC behavior and memory map is futher formalized as an official RISC-V
> + * specification:
> + *
> + * https://github.com/riscv/riscv-plic-spec/blob/master/riscv-plic.adoc
> */
>
> #define MAX_DEVICES 1024
> @@ -177,12 +182,12 @@ static void plic_irq_eoi(struct irq_data *d)
> }
>
> static struct irq_chip plic_chip = {
> - .name = "SiFive PLIC",
> - .irq_mask = plic_irq_mask,
> - .irq_unmask = plic_irq_unmask,
> - .irq_eoi = plic_irq_eoi,
> + .name = "PLIC",
> + .irq_mask = plic_irq_mask,
> + .irq_unmask = plic_irq_unmask,
> + .irq_eoi = plic_irq_eoi,
> #ifdef CONFIG_SMP
> - .irq_set_affinity = plic_set_affinity,
> + .irq_set_affinity = plic_set_affinity,
> #endif
> };
>
> --
> 2.35.1
>


--
Best Regards
Guo Ren

ML: https://lore.kernel.org/linux-csky/

2022-06-27 07:51:23

by Marc Zyngier

Subject: Re: [PATCH v1 2/3] irqchip/sifive-plic: Name the chip more generically

On 2022-06-27 06:12, Samuel Holland wrote:
> The interface for SiFive's PLIC was adopted and clarified by RISC-V as
> the standard PLIC interface. Now that several PLIC implementations by
> different vendors share this same interface, it is somewhat misleading
> to report "SiFive PLIC" to userspace, when no SiFive hardware may be
> present. This is especially the case when some implementations are
> subtly incompatible with the binding and behavior of the SiFive PLIC,
> yet are similar enough to share a driver.

Too late. This is ABI, and not changing, exactly because userspace
sees it.

M.
--
Jazz is not dead. It just smells funny...

2022-06-27 13:59:49

by Samuel Holland

Subject: Re: [PATCH v1 2/3] irqchip/sifive-plic: Name the chip more generically

On 6/27/22 2:11 AM, Marc Zyngier wrote:
> On 2022-06-27 06:12, Samuel Holland wrote:
>> The interface for SiFive's PLIC was adopted and clarified by RISC-V as
>> the standard PLIC interface. Now that several PLIC implementations by
>> different vendors share this same interface, it is somewhat misleading
>> to report "SiFive PLIC" to userspace, when no SiFive hardware may be
>> present. This is especially the case when some implementations are
>> subtly incompatible with the binding and behavior of the SiFive PLIC,
>> yet are similar enough to share a driver.
>
> Too late. This is ABI, and not changing, exactly because userspace
> sees it.

That makes sense. I will drop this patch.

Regards,
Samuel