On 19/04/16 18:13, Eric Auger wrote:
> The purpose is to be able to retrieve the MSI doorbells of an irqchip.
> This is now needed since on some platforms those doorbells must be
> iommu mapped (in case the MSIs transit through an IOMMU that do not
> bypass those transactions).
>
> The assumption is there is a maximum of one doorbell region per cpu.
> The number of doorbells for the whole irqchip is stored in nb_doorbells.
>
> A doorbell region is characterized by its physical address base, size and
> IOMMU protection flag.
>
> irq_chip msi_doorbell_info callback enables to retrieve the doorbells of
> the irqchip.
>
> Signed-off-by: Eric Auger <eric.au...@linaro.org>
>
> ---
>
> v7: creation
> ---
> include/linux/irq.h | 26 ++++++++++++++++++++++----
> 1 file changed, 22 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/irq.h b/include/linux/irq.h
> index c4de623..fdad8c1 100644
> --- a/include/linux/irq.h
> +++ b/include/linux/irq.h
> @@ -312,9 +312,25 @@ static inline irq_hw_number_t irqd_to_hwirq(struct
> irq_data *d)
> return d->hwirq;
> }
>
> -/**
> - * struct irq_chip - hardware interrupt chip descriptor
> - *
> +/* MSI doorbell region */
> +struct irq_chip_msi_doorbell {
> + phys_addr_t base;
> + size_t size;
> + int prot; /* iommu protection flag */
I find this one a bit scary. "int" is a probably not the right type if
it is a set of flags (it should describe both the protection and the
memory attributes - in this case, probably something like Device +
Writeable). You should probably use the same type the IOMMU code uses
(and if it is actually an int, then I'll shut up...).
> +};
> +
> +/*
> + * Describe all the MSI doorbell regions for an irqchip.
> + * A single doorbell region per cpu is assumed.
> + * In case a single doorbell is supported for the whole irqchip,
> + * the region is described in as cpu #0's one
> + */
> +struct irq_chip_msi_doorbell_info {
> + struct irq_chip_msi_doorbell __percpu *percpu_doorbells;
> + int nb_doorbells; /* overall number of doorbells */
> +};
How can size and prot be different from one CPU to another? It really
feels like they should be common. Can I suggest something like this?
struct irq_chip_msi_doorbell_info {
phys_addr_t __percpu *doorbells;
size_t size;
u32 prot;
};
and get rid of struct irq_chip_msi_doorbell altogether?
> +
> +/** * struct irq_chip - hardware interrupt chip descriptor *
> * @name: name for /proc/interrupts
> * @irq_startup: start up the interrupt (defaults to ->enable if NULL)
> * @irq_shutdown: shut down the interrupt (defaults to ->disable if NULL)
> @@ -349,6 +365,7 @@ static inline irq_hw_number_t irqd_to_hwirq(struct
> irq_data *d)
> * @irq_get_irqchip_state: return the internal state of an interrupt
> * @irq_set_irqchip_state: set the internal state of a interrupt
> * @irq_set_vcpu_affinity: optional to target a vCPU in a virtual machine
> + * @msi_doorbell_info: return the MSI doorbell info
> * @ipi_send_single: send a single IPI to destination cpus
> * @ipi_send_mask: send an IPI to destination cpus in cpumask
> * @flags: chip specific flags
> @@ -394,7 +411,8 @@ struct irq_chip {
> int (*irq_set_irqchip_state)(struct irq_data *data, enum
> irqchip_irq_state which, bool state);
>
> int (*irq_set_vcpu_affinity)(struct irq_data *data, void
> *vcpu_info);
> -
> + const struct irq_chip_msi_doorbell_info *(*msi_doorbell_info)(
> + struct irq_data *data);
> void (*ipi_send_single)(struct irq_data *data, unsigned int
> cpu);
> void (*ipi_send_mask)(struct irq_data *data, const struct
> cpumask *dest);
>
>
Thanks,
M.
--
Jazz is not dead. It just smells funny...
