Hi Eric,
On Tue, Jun 07, 2016 at 04:01:26PM +0000, Eric Auger wrote:
> This patch adds the registration of the MSI global doorbell in
> gicv3-its driver.
>
> This will allow the msi layer to iommu_map this doorbell when
> requested.
>
> Signed-off-by: Eric Auger <eric.au...@redhat.com>
> ---
> drivers/irqchip/irq-gic-v3-its.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/irqchip/irq-gic-v3-its.c
> b/drivers/irqchip/irq-gic-v3-its.c
> index 5eb1f9e..ed9dfce 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -29,6 +29,8 @@
> #include <linux/of_platform.h>
> #include <linux/percpu.h>
> #include <linux/slab.h>
> +#include <linux/iommu.h>
> +#include <linux/msi-doorbell.h>
>
> #include <linux/irqchip.h>
> #include <linux/irqchip/arm-gic-v3.h>
> @@ -1607,6 +1609,7 @@ static int __init its_probe(struct device_node *node,
>
> if (of_property_read_bool(node, "msi-controller")) {
> struct msi_domain_info *info;
> + phys_addr_t translater;
>
> info = kzalloc(sizeof(*info), GFP_KERNEL);
> if (!info) {
> @@ -1614,10 +1617,21 @@ static int __init its_probe(struct device_node *node,
> goto out_free_tables;
> }
>
> + translater = its->phys_base + GITS_TRANSLATER;
> + err = msi_doorbell_register_global(its, translater,
> + sizeof(u32),
> + IOMMU_WRITE | IOMMU_MMIO, true);
This doesn't work :(
First we have its_probe registering the global mapping with
doorbell->chip_data = its, which is a pointer to an its_node structure.
But when enabling MSIs for a device, its_irq_domain_alloc puts a pointer
to an *its_device* into irq_data->chip_data. This seems to be a
per-device structure, allocated by its_msi_prepare.
The following call to msi_doorbell_lookup won't ever succeed, because it
will compare its_node to its_device. I can't figure out how to fix it
cleanly at the moment.
Jean-Philippe
> + if (err) {
> + kfree(info);
> + goto out_free_tables;
> + }
> +
> +
> inner_domain = irq_domain_add_tree(node, &its_domain_ops, its);
> if (!inner_domain) {
> err = -ENOMEM;
> kfree(info);
> + msi_doorbell_unregister(its);
> goto out_free_tables;
> }
>
> --
> 1.9.1
>
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