Re: [Xen-devel] [RFC PATCH 13/19] xen/arm: its: implement hw_irq_controller for LPIs

[Vijay Kilari <vijay.kilari@xxxxxxxxx>]

On Mon, Mar 9, 2015 at 9:39 PM, Stefano Stabellini
<stefano.stabellini@xxxxxxxxxxxxx> wrote:
> On Mon, 9 Mar 2015, Vijay Kilari wrote:
>> On Tue, Mar 3, 2015 at 10:58 PM, Stefano Stabellini
>> <stefano.stabellini@xxxxxxxxxxxxx> wrote:
>> > On Mon, 2 Mar 2015, vijay.kilari@xxxxxxxxx wrote:
>> >> From: Vijaya Kumar K <Vijaya.Kumar@xxxxxxxxxxxxxxxxxx>
>> >>
>> >> This patch implements hw_irq_controller api's required
>> >> to handle LPI's.
>> >>
>> >> Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@xxxxxxxxxxxxxxxxxx>
>> >> ---
>> >>  xen/arch/arm/gic-v3-its.c |  104 
>> >> ++++++++++++++++++++++++++++++++++++++++++++-
>> >>  xen/arch/arm/gic.c        |   11 +++++
>> >>  xen/include/asm-arm/gic.h |    8 +++-
>> >>  3 files changed, 121 insertions(+), 2 deletions(-)
>> >>
>> >> diff --git a/xen/arch/arm/gic-v3-its.c b/xen/arch/arm/gic-v3-its.c
>> >> index 5d9550f..b2c3320 100644
>> >> --- a/xen/arch/arm/gic-v3-its.c
>> >> +++ b/xen/arch/arm/gic-v3-its.c
>> >> @@ -140,6 +140,9 @@ struct its_cmd_desc {
>> >>  typedef struct its_collection *(*its_cmd_builder_t)(struct its_cmd_block 
>> >> *,
>> >>                                  struct its_cmd_desc *);
>> >>
>> >> +static void its_send_movi(struct its_node *its, struct its_collection 
>> >> *col,
>> >> +                          u32 dev_id, u32 id);
>> >> +
>> >>  uint32_t its_get_pta_type(void)
>> >>  {
>> >>      return pta_type;
>> >> @@ -244,6 +247,103 @@ int its_get_physical_cid(uint32_t *col_id, uint64_t 
>> >> vta)
>> >>      return 1;
>> >>  }
>> >>
>> >> +static void lpi_set_config(u32 hwirq, u32 id, int enable)
>> >> +{
>> >> +    u8 *cfg;
>> >> +
>> >> +    cfg = gic_rdists->prop_page + hwirq - NR_GIC_LPI;
>> >> +
>> >> +    if ( enable )
>> >> +        *cfg |= (1 << 0);
>> >> +    else
>> >> +        *cfg &= ~(1 << 0);
>> >> +
>> >> +    /*
>> >> +     * Make the above write visible to the redistributors.
>> >> +     * And yes, we're flushing exactly: One. Single. Byte.
>> >> +     * Humpf...
>> >> +     */
>> >> +    if (gic_rdists->flags & RDIST_FLAGS_PROPBASE_NEEDS_FLUSHING)
>> >> +        clean_dcache_va_range(cfg, sizeof(*cfg));
>> >> +    else
>> >> +        dsb(ishst);
>> >> +}
>> >> +
>> >> +static void its_mask_irq(struct irq_desc *d)
>> >> +{
>> >> +    u32 id;
>> >> +
>> >> +    id = d->irq;
>> >> +    set_bit(_IRQ_DISABLED, &d->status);
>> >> +    lpi_set_config(d->irq, id, 0);
>> >> +}
>> >> +
>> >> +static void its_unmask_irq(struct irq_desc *d)
>> >> +{
>> >> +    u32 id;
>> >> +
>> >> +    id = d->irq;
>> >> +    clear_bit(_IRQ_DISABLED, &d->status);
>> >> +    lpi_set_config(d->irq, id, 1);
>> >> +}
>> >> +
>> >> +static unsigned int its_irq_startup(struct irq_desc *desc)
>> >> +{
>> >> +    its_unmask_irq(desc);
>> >> +
>> >> +    return 0;
>> >> +}
>> >> +
>> >> +static void its_irq_shutdown(struct irq_desc *desc)
>> >> +{
>> >> +    its_mask_irq(desc);
>> >> +}
>> >> +
>> >> +static void its_eoi_irq(struct irq_desc *d)
>> >> +{
>> >> +    gic_eoi_irq(d);
>> >> +}
>> >> +
>> >> +static void its_ack_irq(struct irq_desc *desc)
>> >> +{
>> >> +    /* No ACK -- reading IAR has done this for us */
>> >> +}
>> >> +
>> >> +static void its_set_affinity(struct irq_desc *d, const cpumask_t 
>> >> *mask_val)
>> >> +{
>> >> +    /* XXX: check cpumask_any or cpu_online_map is ok? */
>> >> +    cpumask_t online_mask;
>> >> +    unsigned int cpu;
>> >> +    struct vits_device *its_dev = irq_get_desc_data(d);
>> >> +    struct its_collection *target_col;
>> >> +    uint32_t id;
>> >> +
>> >> +    cpumask_and(&online_mask, mask_val, &cpu_online_map);
>> >> +    cpu = cpumask_any(&online_mask);
>> >> +    /* Physical collection id */
>> >> +    target_col = &its->collections[cpu];
>> >> +    /* Physical irq is considered not virq */
>> >> +    id = d->irq;
>> >> +
>> >> +    its_send_movi(its, target_col, its_dev->dev_id, id);
>> >> +}
>> >> +
>> >> +/* TODO: To implement set_affinity */
>> >> +static const hw_irq_controller gic_guest_its_type = {
>> >> +    .typename     = "gic-its",
>> >> +    .startup      = its_irq_startup,
>> >> +    .shutdown     = its_irq_shutdown,
>> >> +    .enable       = its_unmask_irq,
>> >> +    .disable      = its_mask_irq,
>> >> +    .ack          = its_ack_irq,
>> >> +    .end          = its_eoi_irq,
>> >> +    .set_affinity = its_set_affinity,
>> >> +};
>> >> +
>> >> +static const struct gic_its_hw_operations gic_its_ops = {
>> >> +    .gic_guest_lpi_type  = &gic_guest_its_type,
>> >> +};
>> >
>> > Aside from the one call to its_send_movi, nothing here is ITS specific.
>> > In fact I would just move all this to gic-v3.c as it feels like part of
>> > the GICv3 driver rather than the ITS driver.
>>
>> its_mask_irq(), its_umask_irq() & its_set_affinity() are different for ITS.
>
> It looks like they are different because they deal with LPIs. If that is
> the only difference, then I think they should be in gic-v3.c. LPIs in
> general works regardless of the presence of an ITS, right?

OK. I will take care. Yes LPI works without ITS using GICR_{SET,CLR}LPIR
registers. I have not added this support for now.

Regards
Vijay

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