On Thu, Aug 14, 2025 at 07:28:32AM +0800, Inochi Amaoto wrote:
> As the RISC-V PLIC can not apply affinity setting without calling
> irq_enable(), it will make the interrupt unavailble when using as
> an underlying IRQ chip for MSI controller.
s/unavailble/unavailable/ (mentioned previously)
> Implement .irq_startup() and .irq_shutdown() for the PCI MSI and
> MSI-X templates. For chips that specify MSI_FLAG_PCI_MSI_STARTUP_PARENT,
> these startup and shutdown the parent as well, which allows the
> irq on the parent chip to be enabled if the irq is not enabled
> when allocating. This is necessary for the MSI controllers which
> use PLIC as underlying IRQ chip.
s/irq/IRQ/ a couple times above
> Suggested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Signed-off-by: Inochi Amaoto <inochiama@xxxxxxxxx>
Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Thomas, I assume you'll merge this series; let me know if not.
> ---
> drivers/pci/msi/irqdomain.c | 52 +++++++++++++++++++++++++++++++++++++
> include/linux/msi.h | 2 ++
> 2 files changed, 54 insertions(+)
>
> diff --git a/drivers/pci/msi/irqdomain.c b/drivers/pci/msi/irqdomain.c
> index 0938ef7ebabf..e0a800f918e8 100644
> --- a/drivers/pci/msi/irqdomain.c
> +++ b/drivers/pci/msi/irqdomain.c
> @@ -148,6 +148,23 @@ static void pci_device_domain_set_desc(msi_alloc_info_t *arg, struct msi_desc *d
> arg->hwirq = desc->msi_index;
> }
>
> +static void cond_shutdown_parent(struct irq_data *data)
> +{
> + struct msi_domain_info *info = data->domain->host_data;
> +
> + if (unlikely(info->flags & MSI_FLAG_PCI_MSI_STARTUP_PARENT))
> + irq_chip_shutdown_parent(data);
> +}
> +
> +static unsigned int cond_startup_parent(struct irq_data *data)
> +{
> + struct msi_domain_info *info = data->domain->host_data;
> +
> + if (unlikely(info->flags & MSI_FLAG_PCI_MSI_STARTUP_PARENT))
> + return irq_chip_startup_parent(data);
> + return 0;
> +}
> +
> static __always_inline void cond_mask_parent(struct irq_data *data)
> {
> struct msi_domain_info *info = data->domain->host_data;
> @@ -164,6 +181,23 @@ static __always_inline void cond_unmask_parent(struct irq_data *data)
> irq_chip_unmask_parent(data);
> }
>
> +static void pci_irq_shutdown_msi(struct irq_data *data)
> +{
> + struct msi_desc *desc = irq_data_get_msi_desc(data);
> +
> + pci_msi_mask(desc, BIT(data->irq - desc->irq));
> + cond_shutdown_parent(data);
> +}
> +
> +static unsigned int pci_irq_startup_msi(struct irq_data *data)
> +{
> + struct msi_desc *desc = irq_data_get_msi_desc(data);
> + unsigned int ret = cond_startup_parent(data);
> +
> + pci_msi_unmask(desc, BIT(data->irq - desc->irq));
> + return ret;
> +}
> +
> static void pci_irq_mask_msi(struct irq_data *data)
> {
> struct msi_desc *desc = irq_data_get_msi_desc(data);
> @@ -194,6 +228,8 @@ static void pci_irq_unmask_msi(struct irq_data *data)
> static const struct msi_domain_template pci_msi_template = {
> .chip = {
> .name = "PCI-MSI",
> + .irq_startup = pci_irq_startup_msi,
> + .irq_shutdown = pci_irq_shutdown_msi,
> .irq_mask = pci_irq_mask_msi,
> .irq_unmask = pci_irq_unmask_msi,
> .irq_write_msi_msg = pci_msi_domain_write_msg,
> @@ -210,6 +246,20 @@ static const struct msi_domain_template pci_msi_template = {
> },
> };
>
> +static void pci_irq_shutdown_msix(struct irq_data *data)
> +{
> + pci_msix_mask(irq_data_get_msi_desc(data));
> + cond_shutdown_parent(data);
> +}
> +
> +static unsigned int pci_irq_startup_msix(struct irq_data *data)
> +{
> + unsigned int ret = cond_startup_parent(data);
> +
> + pci_msix_unmask(irq_data_get_msi_desc(data));
> + return ret;
> +}
> +
> static void pci_irq_mask_msix(struct irq_data *data)
> {
> pci_msix_mask(irq_data_get_msi_desc(data));
> @@ -234,6 +284,8 @@ EXPORT_SYMBOL_GPL(pci_msix_prepare_desc);
> static const struct msi_domain_template pci_msix_template = {
> .chip = {
> .name = "PCI-MSIX",
> + .irq_startup = pci_irq_startup_msix,
> + .irq_shutdown = pci_irq_shutdown_msix,
> .irq_mask = pci_irq_mask_msix,
> .irq_unmask = pci_irq_unmask_msix,
> .irq_write_msi_msg = pci_msi_domain_write_msg,
> diff --git a/include/linux/msi.h b/include/linux/msi.h
> index e5e86a8529fb..3111ba95fbde 100644
> --- a/include/linux/msi.h
> +++ b/include/linux/msi.h
> @@ -568,6 +568,8 @@ enum {
> MSI_FLAG_PARENT_PM_DEV = (1 << 8),
> /* Support for parent mask/unmask */
> MSI_FLAG_PCI_MSI_MASK_PARENT = (1 << 9),
> + /* Support for parent startup/shutdown */
> + MSI_FLAG_PCI_MSI_STARTUP_PARENT = (1 << 10),
>
> /* Mask for the generic functionality */
> MSI_GENERIC_FLAGS_MASK = GENMASK(15, 0),
> --
> 2.50.1
>
