From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- drivers/i2c/busses/i2c-virtio.c | 278 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 278 insertions(+) create mode 100644 drivers/i2c/busses/i2c-virtio.c (limited to 'drivers/i2c/busses/i2c-virtio.c') diff --git a/drivers/i2c/busses/i2c-virtio.c b/drivers/i2c/busses/i2c-virtio.c new file mode 100644 index 0000000000..c60ae531ba --- /dev/null +++ b/drivers/i2c/busses/i2c-virtio.c @@ -0,0 +1,278 @@ +// 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 + * @adap: I2C adapter for this controller + * @vq: the virtio virtqueue for communication + */ +struct virtio_i2c { + struct virtio_device *vdev; + struct i2c_adapter adap; + struct virtqueue *vq; +}; + +/** + * struct virtio_i2c_req - the virtio I2C request structure + * @completion: completion of virtio I2C message + * @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 completion completion; + 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_req *req; + unsigned int len; + + while ((req = virtqueue_get_buf(vq, &len))) + complete(&req->completion); +} + +static int virtio_i2c_prepare_reqs(struct virtqueue *vq, + struct virtio_i2c_req *reqs, + struct i2c_msg *msgs, int num) +{ + struct scatterlist *sgs[3], out_hdr, msg_buf, in_hdr; + int i; + + for (i = 0; i < num; i++) { + int outcnt = 0, incnt = 0; + + init_completion(&reqs[i].completion); + + /* + * 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 (msgs[i].flags & I2C_M_RD) + reqs[i].out_hdr.flags |= cpu_to_le32(VIRTIO_I2C_FLAGS_M_RD); + + if (i != num - 1) + reqs[i].out_hdr.flags |= cpu_to_le32(VIRTIO_I2C_FLAGS_FAIL_NEXT); + + sg_init_one(&out_hdr, &reqs[i].out_hdr, sizeof(reqs[i].out_hdr)); + sgs[outcnt++] = &out_hdr; + + if (msgs[i].len) { + 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; + + if (virtqueue_add_sgs(vq, sgs, outcnt, incnt, &reqs[i], GFP_KERNEL)) { + 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 num) +{ + bool failed = false; + int i, j = 0; + + for (i = 0; i < num; i++) { + struct virtio_i2c_req *req = &reqs[i]; + + wait_for_completion(&req->completion); + + if (!failed && req->in_hdr.status != VIRTIO_I2C_MSG_OK) + failed = true; + + i2c_put_dma_safe_msg_buf(reqs[i].buf, &msgs[i], !failed); + + if (!failed) + j++; + } + + return 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; + int count; + + reqs = kcalloc(num, sizeof(*reqs), GFP_KERNEL); + if (!reqs) + return -ENOMEM; + + count = virtio_i2c_prepare_reqs(vq, reqs, msgs, num); + if (!count) + goto err_free; + + /* + * For the case where count < num, i.e. we weren't able to queue all the + * msgs, ideally we should abort right away and return early, but some + * of the messages are already sent to the remote I2C controller and the + * virtqueue will be left in undefined state in that case. We kick the + * remote here to clear the virtqueue, so we can try another set of + * messages later on. + */ + virtqueue_kick(vq); + + count = virtio_i2c_complete_reqs(vq, reqs, msgs, count); + +err_free: + kfree(reqs); + return count; +} + +static void virtio_i2c_del_vqs(struct virtio_device *vdev) +{ + virtio_reset_device(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 virtio_i2c *vi; + int ret; + + if (!virtio_has_feature(vdev, VIRTIO_I2C_F_ZERO_LENGTH_REQUEST)) { + dev_err(&vdev->dev, "Zero-length request feature is mandatory\n"); + return -EINVAL; + } + + vi = devm_kzalloc(&vdev->dev, sizeof(*vi), GFP_KERNEL); + if (!vi) + return -ENOMEM; + + vdev->priv = vi; + vi->vdev = vdev; + + ret = virtio_i2c_setup_vqs(vi); + if (ret) + return ret; + + vi->adap.owner = THIS_MODULE; + snprintf(vi->adap.name, sizeof(vi->adap.name), + "i2c_virtio at virtio bus %d", vdev->index); + vi->adap.algo = &virtio_algorithm; + vi->adap.dev.parent = &vdev->dev; + vi->adap.dev.of_node = vdev->dev.of_node; + 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(vdev->dev.parent)); + + ret = i2c_add_adapter(&vi->adap); + if (ret) + virtio_i2c_del_vqs(vdev); + + 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_ADAPTER, VIRTIO_DEV_ANY_ID }, + {} +}; +MODULE_DEVICE_TABLE(virtio, id_table); + +static int virtio_i2c_freeze(struct virtio_device *vdev) +{ + virtio_i2c_del_vqs(vdev); + return 0; +} + +static int virtio_i2c_restore(struct virtio_device *vdev) +{ + return virtio_i2c_setup_vqs(vdev->priv); +} + +static const unsigned int features[] = { + VIRTIO_I2C_F_ZERO_LENGTH_REQUEST, +}; + +static struct virtio_driver virtio_i2c_driver = { + .feature_table = features, + .feature_table_size = ARRAY_SIZE(features), + .id_table = id_table, + .probe = virtio_i2c_probe, + .remove = virtio_i2c_remove, + .driver = { + .name = "i2c_virtio", + }, + .freeze = pm_sleep_ptr(virtio_i2c_freeze), + .restore = pm_sleep_ptr(virtio_i2c_restore), +}; +module_virtio_driver(virtio_i2c_driver); + +MODULE_AUTHOR("Jie Deng "); +MODULE_AUTHOR("Conghui Chen "); +MODULE_DESCRIPTION("Virtio i2c bus driver"); +MODULE_LICENSE("GPL"); -- cgit v1.2.3