[PATCH V5 0/2] gpio: Add virtio based driver
From: Viresh Kumar
Date: Tue Aug 10 2021 - 06:25:38 EST
Hello,
This adds Virtio GPIO driver based on the proposed specification [1].
The specification for basic GPIO operations is already reviewed by Linus and
Arnd, while the IRQ stuff is still under discussion and not finalized.
I am sharing the code, so everyone gets more clarity on how it will work
eventually in Linux.
I have tested this patchset with Qemu guest with help of the libgpiod utility.
I have also tested basic handling of interrupts on the guest side. It works as
expected.
The host side virtio-backend isn't ready yet and my tests only tested the flow
control between guest and host, but didn't play with real GPIO pins. That will
be done once I have a working backend in place (WIP).
V4->V5:
- Use ____cacheline_aligned for buffers.
- Proper locking in place, which avoids the use of work-item for processing
interrupts.
- Separate callbacks for enable/disable of irqs.
- The irq is disabled at the host only for enable/disable now, instead of
mask/unmask.
- mask/unmask only control the queuing of buffers now.
- Use handle_level_irq() instead of handle_fasteoi_irq().
- Other minor changes.
V3->V4:
- Lots of changes, as the specification changed too much. Better forget
everything we have done until now :)
--
Viresh
[1] https://lists.oasis-open.org/archives/virtio-dev/202107/msg00232.html
Viresh Kumar (2):
gpio: Add virtio-gpio driver
gpio: virtio: Add IRQ support
MAINTAINERS | 7 +
drivers/gpio/Kconfig | 10 +
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-virtio.c | 668 +++++++++++++++++++++++++++++++
include/uapi/linux/virtio_gpio.h | 72 ++++
5 files changed, 758 insertions(+)
create mode 100644 drivers/gpio/gpio-virtio.c
create mode 100644 include/uapi/linux/virtio_gpio.h
--
2.31.1.272.g89b43f80a514