From patchwork Thu Apr 23 09:01:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geert Uytterhoeven X-Patchwork-Id: 207031 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C63B4C55193 for ; Thu, 23 Apr 2020 09:06:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AA0912075A for ; Thu, 23 Apr 2020 09:06:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725884AbgDWJG0 (ORCPT ); Thu, 23 Apr 2020 05:06:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49934 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726346AbgDWJGZ (ORCPT ); Thu, 23 Apr 2020 05:06:25 -0400 Received: from xavier.telenet-ops.be (xavier.telenet-ops.be [IPv6:2a02:1800:120:4::f00:14]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 60312C08C5F2 for ; Thu, 23 Apr 2020 02:06:25 -0700 (PDT) Received: from ramsan ([IPv6:2a02:1810:ac12:ed60:89cc:efc7:85ce:4669]) by xavier.telenet-ops.be with bizsmtp id W91L2200Q1RvcFS0191LFG; Thu, 23 Apr 2020 11:01:21 +0200 Received: from rox.of.borg ([192.168.97.57]) by ramsan with esmtp (Exim 4.90_1) (envelope-from ) id 1jRXjU-0006kA-Al; Thu, 23 Apr 2020 11:01:20 +0200 Received: from geert by rox.of.borg with local (Exim 4.90_1) (envelope-from ) id 1jRXjU-0002vS-7c; Thu, 23 Apr 2020 11:01:20 +0200 From: Geert Uytterhoeven To: Peter Maydell , Paolo Bonzini , Alexander Graf , Linus Walleij , Bartosz Golaszewski , Magnus Damm Cc: qemu-arm@nongnu.org, qemu-devel@nongnu.org, linux-gpio@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH QEMU v2 0/5] Add a GPIO backend Date: Thu, 23 Apr 2020 11:01:13 +0200 Message-Id: <20200423090118.11199-1-geert+renesas@glider.be> X-Mailer: git-send-email 2.17.1 Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org Hi all, This patch series adds a GPIO controller backend, to connect virtual GPIOs on the guest to physical GPIOs on the host, and enables support for this using user-creatable PL061 GPIO controller instances. This allows the guest to control any external device connected to the physical GPIOs. While this can be used with an upstream Linux kernel (e.g. using a dedicated GPIO controller connected to an external bus), proper isolation and assignment of GPIOs to virtual machines depends on the GPIO Aggregator[1], which has not been accepted in Linux upstream yet. Aggregating GPIOs and exposing them as a new gpiochip was suggested in response to my proof-of-concept for GPIO virtualization with QEMU[2][3]. Features and limitations: - The backend uses libgpiod on Linux, - For now only GPIO outputs are supported, - The number of GPIO lines mapped is limited to the number of GPIO lines available on the virtual GPIO controller (i.e. 8 on PL061). Future work: - GPIO inputs, - GPIO line configuration, - Optimizations for controlling multiple GPIO lines at once, - ... This series contains 5 patches: - The first two patches refactor the existing code for reuse, - The third patch adds a gneric GPIO backend using libgpiod, - The fourth patch adds gpiodev support to the PL061 driver, - The fifth patch adds dynamic PL061 support to ARM virt. Changes compared to v1[2]: - Drop vgpios and gpios parameters, and map the full gpiochip instead, - Replace the single hardcoded PL061 instance (created by ARM virt) by multiple dynamically created instances, one per imported GPIO controller. For testing, I have pushed this series to the topic/gpio-backend-v2 branch of my git repository at https://github.com/geertu/qemu.git. Sample session on the Renesas Salvator-XS development board: - Unbind keyboard (shared with LEDs) from gpio-keys driver: host$ echo keys > /sys/bus/platform/drivers/gpio-keys/unbind - Aggregate GPIO lines connected to LEDs into a new virtual GPIO chip: host$ echo e6055400.gpio 11-13 \ > /sys/bus/platform/drivers/gpio-aggregator/new_device gpio-aggregator gpio-aggregator.0: 0 => gpio-371 gpio-aggregator gpio-aggregator.0: 1 => gpio-372 gpio-aggregator gpio-aggregator.0: 2 => gpio-373 gpiochip_find_base: found new base at 343 gpio gpiochip10: (gpio-aggregator.0): added GPIO chardev (254:10) gpiochip_setup_dev: registered GPIOs 343 to 345 on device: gpiochip10 (gpio-aggregator.0) - Adjust permissions on /dev/gpiochip10 (optional) - Launch QEMU: host$ aarch64-softmmu/qemu-system-aarch64 -enable-kvm -M virt \ -cpu cortex-a57 -m 1024 -nographic -kernel /path/to/Image \ -device pl061,host=gpio-aggregator.0 ... pl061_gpio c000000.gpio: PL061 GPIO chip registered ... - Control LEDs: guest$ gpioset gpiochip0 0=0 1=1 # LED4 OFF, LED5 ON guest$ gpioset gpiochip0 0=1 1=0 # LED4 ON, LED5 OFF Thanks for your comments! [1] "[PATCH v6 0/8] gpio: Add GPIO Aggregator" (https://lore.kernel.org/linux-gpio/20200324135328.5796-1-geert+renesas@glider.be/) [2] "[PATCH QEMU POC] Add a GPIO backend" (https://lore.kernel.org/linux-gpio/20181003152521.23144-1-geert+renesas@glider.be/) [3] "Getting To Blinky: Virt Edition / Making device pass-through work on embedded ARM" (https://fosdem.org/2019/schedule/event/vai_getting_to_blinky/) Geert Uytterhoeven (5): ARM: PL061: Move TYPE_PL061 to hw/gpio/pl061.h ARM: PL061: Extract pl061_create_fdt() Add a GPIO backend using libgpiod ARM: PL061: Add gpiodev support hw/arm/virt: Add dynamic PL061 GPIO support MAINTAINERS | 7 +++ backends/Makefile.objs | 2 + backends/gpiodev.c | 94 ++++++++++++++++++++++++++++++++++++++++ configure | 28 ++++++++++++ hw/arm/sysbus-fdt.c | 18 ++++++++ hw/arm/virt.c | 21 ++------- hw/gpio/pl061.c | 79 ++++++++++++++++++++++++++++++++- include/hw/gpio/pl061.h | 23 ++++++++++ include/sysemu/gpiodev.h | 12 +++++ qemu-options.hx | 9 ++++ 10 files changed, 275 insertions(+), 18 deletions(-) create mode 100644 backends/gpiodev.c create mode 100644 include/hw/gpio/pl061.h create mode 100644 include/sysemu/gpiodev.h