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



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?


> >
> >
> >>  static u64 its_cmd_ptr_to_offset(struct its_node *its,
> >>                                   struct its_cmd_block *ptr)
> >>  {
> >> @@ -392,7 +492,7 @@ static void its_send_mapc(struct its_node *its, struct 
> >> its_collection *col,
> >>      its_send_single_command(its, its_build_mapc_cmd, &desc);
> >>  }
> >>
> >> -void its_send_movi(struct its_node *its, struct its_collection *col,
> >> +static void its_send_movi(struct its_node *its, struct its_collection 
> >> *col,
> >>                     u32 dev_id, u32 id)
> >>  {
> >>      struct its_cmd_desc desc;
> >> @@ -872,6 +972,8 @@ int its_init(struct dt_device_node *node, struct 
> >> rdist_prop *rdists)
> >>
> >>      its_alloc_lpi_tables();
> >>
> >> +    register_gic_its_ops(&gic_its_ops);
> >> +
> >>      return 0;
> >>  }
> >>
> >> diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
> >> index 390c8b0..fb77387 100644
> >> --- a/xen/arch/arm/gic.c
> >> +++ b/xen/arch/arm/gic.c
> >> @@ -46,12 +46,18 @@ static DEFINE_PER_CPU(uint64_t, lr_mask);
> >>  static void gic_update_one_lr(struct vcpu *v, int i);
> >>
> >>  static const struct gic_hw_operations *gic_hw_ops;
> >> +static const struct gic_its_hw_operations *gic_its_hw_ops;
> >>
> >>  void register_gic_ops(const struct gic_hw_operations *ops)
> >>  {
> >>      gic_hw_ops = ops;
> >>  }
> >>
> >> +void register_gic_its_ops(const struct gic_its_hw_operations *ops)
> >> +{
> >> +    gic_its_hw_ops = ops;
> >> +}
> >
> > Not clear why you need this.
> 
> This is registered to gic driver and the .gic_guest_lpi_type
> field in  gic_its_hw_operations is used to update desc->handler
> of ITS descriptor
> 

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