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SubjectRe: [PATCH v3 09/13] irqchip: GICv3: ITS: MSI support
Hi Marc,
On 2014/11/24 22:35, Marc Zyngier wrote:

> Now, the bit of code that allow us to use the ITS as a MSI controller.
> Both MSI and MSI-X are supported.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> drivers/irqchip/irq-gic-v3-its.c | 176 +++++++++++++++++++++++++++++++++++++
> include/linux/irqchip/arm-gic-v3.h | 6 ++
> 2 files changed, 182 insertions(+)
>
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index d687fd4..532c6df 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -587,12 +587,47 @@ static int its_set_affinity(struct irq_data *d, const struct cpumask *mask_val,
> return IRQ_SET_MASK_OK_DONE;
> }
>
> +static void its_irq_compose_msi_msg(struct irq_data *d, struct msi_msg *msg)
> +{
> + struct its_device *its_dev = irq_data_get_irq_chip_data(d);
> + struct its_node *its;
> + u64 addr;
> +
> + its = its_dev->its;
> + addr = its->phys_base + GITS_TRANSLATER;
> +
> + msg->address_lo = addr & ((1UL << 32) - 1);
> + msg->address_hi = addr >> 32;
> + msg->data = its_get_event_id(d);
> +}
> +
> static struct irq_chip its_irq_chip = {
> .name = "ITS",
> .irq_mask = its_mask_irq,
> .irq_unmask = its_unmask_irq,
> .irq_eoi = its_eoi_irq,
> .irq_set_affinity = its_set_affinity,
> + .irq_compose_msi_msg = its_irq_compose_msi_msg,
> +};
> +
> +static void its_mask_msi_irq(struct irq_data *d)
> +{
> + pci_msi_mask_irq(d);
> + irq_chip_mask_parent(d);
> +}
> +
> +static void its_unmask_msi_irq(struct irq_data *d)
> +{
> + pci_msi_unmask_irq(d);
> + irq_chip_unmask_parent(d);
> +}
> +
> +static struct irq_chip its_msi_irq_chip = {
> + .name = "ITS-MSI",
> + .irq_unmask = its_unmask_msi_irq,
> + .irq_mask = its_mask_msi_irq,
> + .irq_eoi = irq_chip_eoi_parent,
> + .irq_write_msi_msg = pci_msi_domain_write_msg,
> };
>
> /*
> @@ -1055,3 +1090,144 @@ static void its_free_device(struct its_device *its_dev)
> kfree(its_dev->itt);
> kfree(its_dev);
> }
> +
> +static int its_alloc_device_irq(struct its_device *dev, irq_hw_number_t *hwirq)
> +{
> + int idx;
> +
> + idx = find_first_zero_bit(dev->lpi_map, dev->nr_lpis);
> + if (idx == dev->nr_lpis)
> + return -ENOSPC;
> +
> + *hwirq = dev->lpi_base + idx;
> + set_bit(idx, dev->lpi_map);
> +
> + /* Map the GIC irq ID to the device */
> + its_send_mapvi(dev, *hwirq, idx);

It would be better if we do hardware-level initialization in domain.{activate,deactivate}.

> +
> + return 0;
> +}
> +
> +static int its_msi_prepare(struct irq_domain *domain, struct device *dev,
> + int nvec, msi_alloc_info_t *info)
> +{
> + struct pci_dev *pdev;
> + struct its_node *its;
> + u32 dev_id;
> + struct its_device *its_dev;
> +
> + if (!dev_is_pci(dev))
> + return -EINVAL;
> +
> + pdev = to_pci_dev(dev);
> + dev_id = PCI_DEVID(pdev->bus->number, pdev->devfn);
> + its = domain->parent->host_data;
> +
> + its_dev = its_find_device(its, dev_id);
> + if (WARN_ON(its_dev))
> + return -EINVAL;
> +
> + its_dev = its_create_device(its, dev_id, nvec);
> + if (!its_dev)
> + return -ENOMEM;
> +
> + dev_dbg(&pdev->dev, "ITT %d entries, %d bits\n", nvec, ilog2(nvec));
> +
> + info->scratchpad[0].ptr = its_dev;
> + info->scratchpad[1].ptr = dev;
> + return 0;
> +}
> +
> +static struct msi_domain_ops its_pci_msi_ops = {
> + .msi_prepare = its_msi_prepare,
> +};
> +
> +static struct msi_domain_info its_pci_msi_domain_info = {
> + .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
> + MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
> + .ops = &its_pci_msi_ops,
> + .chip = &its_msi_irq_chip,
> +};
> +
> +static int its_irq_gic_domain_alloc(struct irq_domain *domain,
> + unsigned int virq,
> + irq_hw_number_t hwirq)
> +{
> + struct of_phandle_args args;
> +
> + args.np = domain->parent->of_node;
> + args.args_count = 3;
> + args.args[0] = GIC_IRQ_TYPE_LPI;
> + args.args[1] = hwirq;
> + args.args[2] = IRQ_TYPE_EDGE_RISING;
> +
> + return irq_domain_alloc_irqs_parent(domain, virq, 1, &args);
> +}
> +
> +static int its_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
> + unsigned int nr_irqs, void *args)
> +{
> + msi_alloc_info_t *info = args;
> + struct its_device *its_dev = info->scratchpad[0].ptr;
> + irq_hw_number_t hwirq;
> + int err;
> + int i;
> +
> + for (i = 0; i < nr_irqs; i++) {
> + err = its_alloc_device_irq(its_dev, &hwirq);
> + if (err)
> + return err;
> +
> + err = its_irq_gic_domain_alloc(domain, virq + i, hwirq);
> + if (err)
> + return err;
> +
> + irq_domain_set_hwirq_and_chip(domain, virq + i,
> + hwirq, &its_irq_chip, its_dev);
> + dev_dbg(info->scratchpad[1].ptr, "ID:%d pID:%d vID:%d\n",
> + (int)(hwirq - its_dev->lpi_base), (int)hwirq, virq + i);
> + }
> +
> + return 0;
> +}
> +
> +static void its_irq_domain_free(struct irq_domain *domain, unsigned int virq,
> + unsigned int nr_irqs)
> +{
> + struct irq_data *d = irq_domain_get_irq_data(domain, virq);
> + struct its_device *its_dev = irq_data_get_irq_chip_data(d);
> + int i;
> +
> + for (i = 0; i < nr_irqs; i++) {
> + struct irq_data *data = irq_domain_get_irq_data(domain,
> + virq + i);
> + int event = its_get_event_id(data);
> +
> + /* Stop the delivery of interrupts */
> + its_send_discard(its_dev, event);
> +
> + /* Mark interrupt index as unused */
> + clear_bit(event, its_dev->lpi_map);
> +
> + /* Nuke the entry in the domain */
> + irq_domain_reset_irq_data(d);

I think you mean "data" here, instead of "d"?

Regards,
Abel

> + }
> +
> + /* If all interrupts have been freed, start mopping the floor */
> + if (bitmap_empty(its_dev->lpi_map, its_dev->nr_lpis)) {
> + its_lpi_free(its_dev->lpi_map,
> + its_dev->lpi_base,
> + its_dev->nr_lpis);
> +
> + /* Unmap device/itt */
> + its_send_mapd(its_dev, 0);
> + its_free_device(its_dev);
> + }
> +
> + irq_domain_free_irqs_parent(domain, virq, nr_irqs);
> +}
> +
> +static const struct irq_domain_ops its_domain_ops = {
> + .alloc = its_irq_domain_alloc,
> + .free = its_irq_domain_free,
> +};
> diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
> index 21c9d70..0ed30d7 100644
> --- a/include/linux/irqchip/arm-gic-v3.h
> +++ b/include/linux/irqchip/arm-gic-v3.h
> @@ -295,6 +295,12 @@
>
> #include <linux/stringify.h>
>
> +/*
> + * We need a value to serve as a irq-type for LPIs. Choose one that will
> + * hopefully pique the interest of the reviewer.
> + */
> +#define GIC_IRQ_TYPE_LPI 0xa110c8ed
> +
> struct rdists {
> struct {
> void __iomem *rd_base;





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