dcce162559
The virtio specification received a new mandatory feature (VIRTIO_I2C_F_ZERO_LENGTH_REQUEST) for zero length requests. Fail if the feature isn't offered by the device. For each read-request, set the VIRTIO_I2C_FLAGS_M_RD flag, as required by the VIRTIO_I2C_F_ZERO_LENGTH_REQUEST feature. This allows us to support zero length requests, like SMBUS Quick, where the buffer need not be sent anymore. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Link: https://lore.kernel.org/r/7c58868cd26d2fc4bd82d0d8b0dfb55636380110.1634808714.git.viresh.kumar@linaro.org Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Jie Deng <jie.deng@intel.com> # once the spec is merged
47 lines
1.2 KiB
C
47 lines
1.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later WITH Linux-syscall-note */
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/*
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* Definitions for virtio I2C Adpter
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*
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* Copyright (c) 2021 Intel Corporation. All rights reserved.
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*/
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#ifndef _UAPI_LINUX_VIRTIO_I2C_H
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#define _UAPI_LINUX_VIRTIO_I2C_H
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#include <linux/const.h>
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#include <linux/types.h>
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/* Virtio I2C Feature bits */
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#define VIRTIO_I2C_F_ZERO_LENGTH_REQUEST 0
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/* The bit 0 of the @virtio_i2c_out_hdr.@flags, used to group the requests */
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#define VIRTIO_I2C_FLAGS_FAIL_NEXT _BITUL(0)
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/* The bit 1 of the @virtio_i2c_out_hdr.@flags, used to mark a buffer as read */
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#define VIRTIO_I2C_FLAGS_M_RD _BITUL(1)
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/**
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* struct virtio_i2c_out_hdr - the virtio I2C message OUT header
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* @addr: the controlled device address
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* @padding: used to pad to full dword
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* @flags: used for feature extensibility
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*/
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struct virtio_i2c_out_hdr {
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__le16 addr;
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__le16 padding;
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__le32 flags;
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};
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/**
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* struct virtio_i2c_in_hdr - the virtio I2C message IN header
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* @status: the processing result from the backend
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*/
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struct virtio_i2c_in_hdr {
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__u8 status;
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};
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/* The final status written by the device */
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#define VIRTIO_I2C_MSG_OK 0
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#define VIRTIO_I2C_MSG_ERR 1
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#endif /* _UAPI_LINUX_VIRTIO_I2C_H */
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