From patchwork Mon Mar 22 13:35:59 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jie Deng X-Patchwork-Id: 406328 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=-14.8 required=3.0 tests=BAYES_00, DATE_IN_FUTURE_06_12, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, 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 57481C433C1 for ; Mon, 22 Mar 2021 05:36:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 100F761582 for ; Mon, 22 Mar 2021 05:36:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229715AbhCVFgI (ORCPT ); Mon, 22 Mar 2021 01:36:08 -0400 Received: from mga11.intel.com ([192.55.52.93]:10233 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229455AbhCVFfz (ORCPT ); Mon, 22 Mar 2021 01:35:55 -0400 IronPort-SDR: zeiEyZJra9UMErJ1wEsLXYCfx4d2a7uz15cU8GAfk0zM86CbqAo4EyC9pUzd1C207hKnS56SaU ozdp6Yq5gjxA== X-IronPort-AV: E=McAfee;i="6000,8403,9930"; a="186885659" X-IronPort-AV: E=Sophos;i="5.81,268,1610438400"; d="scan'208";a="186885659" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Mar 2021 22:35:54 -0700 IronPort-SDR: 2ZW1DZbfcUSwP/No8SotJaLYrONhAOVg1AvxiJOgGdvPD/livn1nvCVb/kj0SIljULUsrlFwup cdoA6SQq1anA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.81,268,1610438400"; d="scan'208";a="513187820" Received: from jiedeng-optiplex-7050.sh.intel.com ([10.239.154.104]) by fmsmga001.fm.intel.com with ESMTP; 21 Mar 2021 22:35:49 -0700 From: Jie Deng To: linux-i2c@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org Cc: mst@redhat.com, wsa@kernel.org, jasowang@redhat.com, wsa+renesas@sang-engineering.com, andriy.shevchenko@linux.intel.com, conghui.chen@intel.com, arnd@arndb.de, kblaiech@mellanox.com, jarkko.nikula@linux.intel.com, Sergey.Semin@baikalelectronics.ru, rppt@kernel.org, jie.deng@intel.com, loic.poulain@linaro.org, tali.perry1@gmail.com, u.kleine-koenig@pengutronix.de, bjorn.andersson@linaro.org, yu1.wang@intel.com, shuo.a.liu@intel.com, viresh.kumar@linaro.org, stefanha@redhat.com, pbonzini@redhat.com Subject: [PATCH v9] i2c: virtio: add a virtio i2c frontend driver Date: Mon, 22 Mar 2021 21:35:59 +0800 Message-Id: X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org Add an I2C bus driver for virtio para-virtualization. The controller can be emulated by the backend driver in any device model software by following the virtio protocol. The device specification can be found on https://lists.oasis-open.org/archives/virtio-comment/202101/msg00008.html. By following the specification, people may implement different backend drivers to emulate different controllers according to their needs. Co-developed-by: Conghui Chen Signed-off-by: Conghui Chen Signed-off-by: Jie Deng --- Changes in v9: - Remove the virtio_adapter and update its members in probe. - Refined the virtio_i2c_complete_reqs for buf free. Changes in v8: - Make virtio_i2c.adap a pointer. - Mark members in virtio_i2c_req with ____cacheline_aligned. Changes in v7: - Remove unused headers. - Update Makefile and Kconfig. - Add the cleanup after completing reqs. - Avoid memcpy for data marked with I2C_M_DMA_SAFE. - Fix something reported by kernel test robot. Changes in v6: - Move struct virtio_i2c_req into the driver. - Use only one buf in struct virtio_i2c_req. Changes in v5: - The first version based on the acked specification. drivers/i2c/busses/Kconfig | 11 ++ drivers/i2c/busses/Makefile | 3 + drivers/i2c/busses/i2c-virtio.c | 286 ++++++++++++++++++++++++++++++++++++++++ include/uapi/linux/virtio_i2c.h | 40 ++++++ include/uapi/linux/virtio_ids.h | 1 + 5 files changed, 341 insertions(+) create mode 100644 drivers/i2c/busses/i2c-virtio.c create mode 100644 include/uapi/linux/virtio_i2c.h diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 05ebf75..cb8d0d8 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -21,6 +21,17 @@ config I2C_ALI1535 This driver can also be built as a module. If so, the module will be called i2c-ali1535. +config I2C_VIRTIO + tristate "Virtio I2C Adapter" + select VIRTIO + help + If you say yes to this option, support will be included for the virtio + I2C adapter driver. The hardware can be emulated by any device model + software according to the virtio protocol. + + This driver can also be built as a module. If so, the module + will be called i2c-virtio. + config I2C_ALI1563 tristate "ALI 1563" depends on PCI diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index 615f35e..efdd3f3 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -145,4 +145,7 @@ obj-$(CONFIG_I2C_XGENE_SLIMPRO) += i2c-xgene-slimpro.o obj-$(CONFIG_SCx200_ACB) += scx200_acb.o obj-$(CONFIG_I2C_FSI) += i2c-fsi.o +# VIRTIO I2C host controller driver +obj-$(CONFIG_I2C_VIRTIO) += i2c-virtio.o + ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG diff --git a/drivers/i2c/busses/i2c-virtio.c b/drivers/i2c/busses/i2c-virtio.c new file mode 100644 index 0000000..316986e --- /dev/null +++ b/drivers/i2c/busses/i2c-virtio.c @@ -0,0 +1,286 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Virtio I2C Bus Driver + * + * The Virtio I2C Specification: + * https://raw.githubusercontent.com/oasis-tcs/virtio-spec/master/virtio-i2c.tex + * + * Copyright (c) 2021 Intel Corporation. All rights reserved. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/** + * struct virtio_i2c - virtio I2C data + * @vdev: virtio device for this controller + * @completion: completion of virtio I2C message + * @adap: I2C adapter for this controller + * @i2c_lock: lock for virtqueue processing + * @vq: the virtio virtqueue for communication + */ +struct virtio_i2c { + struct virtio_device *vdev; + struct completion completion; + struct i2c_adapter adap; + struct mutex lock; + struct virtqueue *vq; +}; + +/** + * struct virtio_i2c_req - the virtio I2C request structure + * @out_hdr: the OUT header of the virtio I2C message + * @buf: the buffer into which data is read, or from which it's written + * @in_hdr: the IN header of the virtio I2C message + */ +struct virtio_i2c_req { + struct virtio_i2c_out_hdr out_hdr ____cacheline_aligned; + uint8_t *buf ____cacheline_aligned; + struct virtio_i2c_in_hdr in_hdr ____cacheline_aligned; +}; + +static void virtio_i2c_msg_done(struct virtqueue *vq) +{ + struct virtio_i2c *vi = vq->vdev->priv; + + complete(&vi->completion); +} + +static int virtio_i2c_send_reqs(struct virtqueue *vq, + struct virtio_i2c_req *reqs, + struct i2c_msg *msgs, int nr) +{ + struct scatterlist *sgs[3], out_hdr, msg_buf, in_hdr; + int i, outcnt, incnt, err = 0; + + for (i = 0; i < nr; i++) { + if (!msgs[i].len) + break; + + /* + * Only 7-bit mode supported for this moment. For the address format, + * Please check the Virtio I2C Specification. + */ + reqs[i].out_hdr.addr = cpu_to_le16(msgs[i].addr << 1); + + if (i != nr - 1) + reqs[i].out_hdr.flags = cpu_to_le32(VIRTIO_I2C_FLAGS_FAIL_NEXT); + + outcnt = incnt = 0; + sg_init_one(&out_hdr, &reqs[i].out_hdr, sizeof(reqs[i].out_hdr)); + sgs[outcnt++] = &out_hdr; + + reqs[i].buf = i2c_get_dma_safe_msg_buf(&msgs[i], 1); + if (!reqs[i].buf) + break; + + sg_init_one(&msg_buf, reqs[i].buf, msgs[i].len); + + if (msgs[i].flags & I2C_M_RD) + sgs[outcnt + incnt++] = &msg_buf; + else + sgs[outcnt++] = &msg_buf; + + sg_init_one(&in_hdr, &reqs[i].in_hdr, sizeof(reqs[i].in_hdr)); + sgs[outcnt + incnt++] = &in_hdr; + + err = virtqueue_add_sgs(vq, sgs, outcnt, incnt, &reqs[i], GFP_KERNEL); + if (err < 0) { + pr_err("failed to add msg[%d] to virtqueue.\n", i); + i2c_put_dma_safe_msg_buf(reqs[i].buf, &msgs[i], false); + break; + } + } + + return i; +} + +static int virtio_i2c_complete_reqs(struct virtqueue *vq, + struct virtio_i2c_req *reqs, + struct i2c_msg *msgs, int nr, + bool timeout) +{ + struct virtio_i2c_req *req; + bool err_found = false; + unsigned int len; + int i, j = 0; + + for (i = 0; i < nr; i++) { + /* Detach the ith request from the vq */ + req = virtqueue_get_buf(vq, &len); + + if (timeout || err_found) { + i2c_put_dma_safe_msg_buf(reqs[i].buf, &msgs[i], false); + continue; + } + + /* + * Condition (req && req == &reqs[i]) should always meet since + * we have total nr requests in the vq. + */ + if (WARN_ON(!(req && req == &reqs[i])) || + (req->in_hdr.status != VIRTIO_I2C_MSG_OK)) { + err_found = true; + i2c_put_dma_safe_msg_buf(reqs[i].buf, &msgs[i], false); + continue; + } + + i2c_put_dma_safe_msg_buf(reqs[i].buf, &msgs[i], true); + ++j; + } + + return (timeout ? -ETIMEDOUT : j); +} + +static int virtio_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) +{ + struct virtio_i2c *vi = i2c_get_adapdata(adap); + struct virtqueue *vq = vi->vq; + struct virtio_i2c_req *reqs; + unsigned long time_left; + int ret, nr; + + reqs = kcalloc(num, sizeof(*reqs), GFP_KERNEL); + if (!reqs) + return -ENOMEM; + + mutex_lock(&vi->lock); + + ret = virtio_i2c_send_reqs(vq, reqs, msgs, num); + if (ret == 0) + goto err_unlock_free; + + nr = ret; + reinit_completion(&vi->completion); + virtqueue_kick(vq); + + time_left = wait_for_completion_timeout(&vi->completion, adap->timeout); + if (!time_left) { + dev_err(&adap->dev, "virtio i2c backend timeout.\n"); + ret = virtio_i2c_complete_reqs(vq, reqs, msgs, nr, true); + goto err_unlock_free; + } + + ret = virtio_i2c_complete_reqs(vq, reqs, msgs, nr, false); + +err_unlock_free: + mutex_unlock(&vi->lock); + kfree(reqs); + return ret; +} + +static void virtio_i2c_del_vqs(struct virtio_device *vdev) +{ + vdev->config->reset(vdev); + vdev->config->del_vqs(vdev); +} + +static int virtio_i2c_setup_vqs(struct virtio_i2c *vi) +{ + struct virtio_device *vdev = vi->vdev; + + vi->vq = virtio_find_single_vq(vdev, virtio_i2c_msg_done, "msg"); + return PTR_ERR_OR_ZERO(vi->vq); +} + +static u32 virtio_i2c_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static struct i2c_algorithm virtio_algorithm = { + .master_xfer = virtio_i2c_xfer, + .functionality = virtio_i2c_func, +}; + +static int virtio_i2c_probe(struct virtio_device *vdev) +{ + struct device *pdev = vdev->dev.parent; + struct virtio_i2c *vi; + int ret; + + vi = devm_kzalloc(&vdev->dev, sizeof(*vi), GFP_KERNEL); + if (!vi) + return -ENOMEM; + + vdev->priv = vi; + vi->vdev = vdev; + + mutex_init(&vi->lock); + init_completion(&vi->completion); + + ret = virtio_i2c_setup_vqs(vi); + if (ret) + return ret; + + vi->adap.owner = THIS_MODULE; + snprintf(vi->adap.name, sizeof(vi->adap.name), "Virtio I2C Adapter"); + vi->adap.class = I2C_CLASS_DEPRECATED; + vi->adap.algo = &virtio_algorithm; + vi->adap.dev.parent = &vdev->dev; + vi->adap.timeout = HZ / 10; + i2c_set_adapdata(&vi->adap, vi); + + /* Setup ACPI node for controlled devices which will be probed through ACPI */ + ACPI_COMPANION_SET(&vi->adap.dev, ACPI_COMPANION(pdev)); + + ret = i2c_add_adapter(&vi->adap); + if (ret) { + virtio_i2c_del_vqs(vdev); + dev_err(&vdev->dev, "failed to add virtio-i2c adapter.\n"); + } + + return ret; +} + +static void virtio_i2c_remove(struct virtio_device *vdev) +{ + struct virtio_i2c *vi = vdev->priv; + + i2c_del_adapter(&vi->adap); + virtio_i2c_del_vqs(vdev); +} + +static struct virtio_device_id id_table[] = { + { VIRTIO_ID_I2C_ADPTER, VIRTIO_DEV_ANY_ID }, + {} +}; +MODULE_DEVICE_TABLE(virtio, id_table); + +static int __maybe_unused virtio_i2c_freeze(struct virtio_device *vdev) +{ + virtio_i2c_del_vqs(vdev); + return 0; +} + +static int __maybe_unused virtio_i2c_restore(struct virtio_device *vdev) +{ + return virtio_i2c_setup_vqs(vdev->priv); +} + +static struct virtio_driver virtio_i2c_driver = { + .id_table = id_table, + .probe = virtio_i2c_probe, + .remove = virtio_i2c_remove, + .driver = { + .name = "i2c_virtio", + }, +#ifdef CONFIG_PM_SLEEP + .freeze = virtio_i2c_freeze, + .restore = virtio_i2c_restore, +#endif +}; +module_virtio_driver(virtio_i2c_driver); + +MODULE_AUTHOR("Jie Deng "); +MODULE_AUTHOR("Conghui Chen "); +MODULE_DESCRIPTION("Virtio i2c bus driver"); +MODULE_LICENSE("GPL"); diff --git a/include/uapi/linux/virtio_i2c.h b/include/uapi/linux/virtio_i2c.h new file mode 100644 index 0000000..bbcfb2c --- /dev/null +++ b/include/uapi/linux/virtio_i2c.h @@ -0,0 +1,40 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later WITH Linux-syscall-note */ +/* + * Definitions for virtio I2C Adpter + * + * Copyright (c) 2021 Intel Corporation. All rights reserved. + */ + +#ifndef _UAPI_LINUX_VIRTIO_I2C_H +#define _UAPI_LINUX_VIRTIO_I2C_H + +#include + +/* The bit 0 of the @virtio_i2c_out_hdr.@flags, used to group the requests */ +#define VIRTIO_I2C_FLAGS_FAIL_NEXT 0x00000001 + +/** + * struct virtio_i2c_out_hdr - the virtio I2C message OUT header + * @addr: the controlled device address + * @padding: used to pad to full dword + * @flags: used for feature extensibility + */ +struct virtio_i2c_out_hdr { + __le16 addr; + __le16 padding; + __le32 flags; +}; + +/** + * struct virtio_i2c_in_hdr - the virtio I2C message IN header + * @status: the processing result from the backend + */ +struct virtio_i2c_in_hdr { + __u8 status; +}; + +/* The final status written by the device */ +#define VIRTIO_I2C_MSG_OK 0 +#define VIRTIO_I2C_MSG_ERR 1 + +#endif /* _UAPI_LINUX_VIRTIO_I2C_H */ diff --git a/include/uapi/linux/virtio_ids.h b/include/uapi/linux/virtio_ids.h index bc1c062..6ae32db 100644 --- a/include/uapi/linux/virtio_ids.h +++ b/include/uapi/linux/virtio_ids.h @@ -54,5 +54,6 @@ #define VIRTIO_ID_FS 26 /* virtio filesystem */ #define VIRTIO_ID_PMEM 27 /* virtio pmem */ #define VIRTIO_ID_MAC80211_HWSIM 29 /* virtio mac80211-hwsim */ +#define VIRTIO_ID_I2C_ADPTER 34 /* virtio i2c adpter */ #endif /* _LINUX_VIRTIO_IDS_H */