On Wed, Sep 5, 2018 at 12:26 AM, Christoph Hellwig <h...@infradead.org> wrote: > On Tue, Sep 04, 2018 at 06:15:12PM +0530, Anup Patel wrote: >> This patch selects following GENERIC_IRQ kconfig options: >> GENERIC_IRQ_MULTI_HANDLER > > This is already selected by arch/riscv/Kconfig. > >> GENERIC_IRQ_PROBE > > This is something only used by ISA drivers. Why would we want that > on RISC-V?
Yes, thanks for pointing. GENERIC_IRQ_PROBE is not required at this time. I will drop this selection. May be will re-consider later. > >> GENERIC_IRQ_SHOW_LEVEL > > We don't really have any special level triggerd irq handling in > RISC-V. That being said this is trivial and I don't see why it > even is a Kconfig option. Please have a discussion with Thomas > and Marc on why we have this option instead of a default. Most of MMIO device interrupts are level-interrupts. In fact, all HW interrupt lines coming to PLIC will be level-interrupts. It's just that PLIC does not implement state machine to sample Level-IRQs and Edge-IRQs differently. Even the interrupt-controller virtualization in hypervisors deal with Level and Edge interrupts differently. I am sure we will see both Level and Edge triggered interrupts in RISC-V system. The MMIO device interrupts will be mostly Level triggered and PCI MSIs will be mapped as Edge triggered by MSI controller. We should definitely select GENERIC_IRQ_SHOW_LEVEL so that nature of IRQ interrupt line is evident in /proc/interrupts. > >> HANDLE_DOMAIN_IRQ > > We aren't using handle_domain_irq anywhere in RISC-V, no need to > build this. The new RISC-V local interrupt controller driver introduced by this patchset uses handle_domain_irq(). The main advantage of handle_domain_irq() is that it helps reduce few lines of code which is otherwise common across interrupt-controller drivers (mostly code related to irq_enter(), irq_exit(), and set_irq_regs()). Regards, Anup
