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path: root/drivers/i2c/busses/i2c-virtio.c
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2025-05-19i2c: virtio: Replace dev_err() with dev_err_probe() in probe functionEnrico Zanda
This simplifies the code while improving log. Signed-off-by: Enrico Zanda <e.zanda1@gmail.com> Link: https://lore.kernel.org/r/20250415183447.396277-8-e.zanda1@gmail.com Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
2024-09-10i2c: virtio: Constify struct i2c_algorithm and struct virtio_device_idChristophe JAILLET
'struct i2c_algorithm' and 'struct virtio_device_id' are not modified in this driver. Constifying this structure moves some data to a read-only section, so increase overall security, especially when the structure holds some function pointers, which is the case for struct i2c_algorithm. On a x86_64, with allmodconfig: Before: ====== text data bss dec hex filename 6663 568 16 7247 1c4f drivers/i2c/busses/i2c-virtio.o After: ===== text data bss dec hex filename 6735 472 16 7223 1c37 drivers/i2c/busses/i2c-virtio.o -- Compile tested only Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
2024-07-11i2c: virtio: reword according to newest specificationWolfram Sang
Change the wording of this driver wrt. the newest I2C v7 and SMBus 3.2 specifications and replace "master/slave" with more appropriate terms. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Andi Shyti <andi.shyti@kernel.org> Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
2023-08-08i2c: virtio: Remove #ifdef guards for PM related functionsPaul Cercueil
Use the new PM macros for the suspend and resume functions to be automatically dropped by the compiler when CONFIG_PM or CONFIG_PM_SLEEP are disabled, without having to use #ifdef guards. This has the advantage of always compiling these functions in, independently of any Kconfig option. Thanks to that, bugs and other regressions are subsequently easier to catch. Signed-off-by: Paul Cercueil <paul@crapouillou.net> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Link: https://lore.kernel.org/r/20230722115310.27681-5-paul@crapouillou.net Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
2022-01-14virtio: wrap config->reset callsMichael S. Tsirkin
This will enable cleanups down the road. The idea is to disable cbs, then add "flush_queued_cbs" callback as a parameter, this way drivers can flush any work queued after callbacks have been disabled. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Link: https://lore.kernel.org/r/20211013105226.20225-1-mst@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2021-12-09i2c: virtio: fix completion handlingVincent Whitchurch
The driver currently assumes that the notify callback is only received when the device is done with all the queued buffers. However, this is not true, since the notify callback could be called without any of the queued buffers being completed (for example, with virtio-pci and shared interrupts) or with only some of the buffers being completed (since the driver makes them available to the device in multiple separate virtqueue_add_sgs() calls). This can lead to incorrect data on the I2C bus or memory corruption in the guest if the device operates on buffers which are have been freed by the driver. (The WARN_ON in the driver is also triggered.) BUG kmalloc-128 (Tainted: G W ): Poison overwritten First byte 0x0 instead of 0x6b Allocated in i2cdev_ioctl_rdwr+0x9d/0x1de age=243 cpu=0 pid=28 memdup_user+0x2e/0xbd i2cdev_ioctl_rdwr+0x9d/0x1de i2cdev_ioctl+0x247/0x2ed vfs_ioctl+0x21/0x30 sys_ioctl+0xb18/0xb41 Freed in i2cdev_ioctl_rdwr+0x1bb/0x1de age=68 cpu=0 pid=28 kfree+0x1bd/0x1cc i2cdev_ioctl_rdwr+0x1bb/0x1de i2cdev_ioctl+0x247/0x2ed vfs_ioctl+0x21/0x30 sys_ioctl+0xb18/0xb41 Fix this by calling virtio_get_buf() from the notify handler like other virtio drivers and by actually waiting for all the buffers to be completed. Fixes: 3cfc88380413d20f ("i2c: virtio: add a virtio i2c frontend driver") Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Wolfram Sang <wsa@kernel.org>
2021-11-23i2c: virtio: disable timeout handlingVincent Whitchurch
If a timeout is hit, it can result is incorrect data on the I2C bus and/or memory corruptions in the guest since the device can still be operating on the buffers it was given while the guest has freed them. Here is, for example, the start of a slub_debug splat which was triggered on the next transfer after one transfer was forced to timeout by setting a breakpoint in the backend (rust-vmm/vhost-device): BUG kmalloc-1k (Not tainted): Poison overwritten First byte 0x1 instead of 0x6b Allocated in virtio_i2c_xfer+0x65/0x35c age=350 cpu=0 pid=29 __kmalloc+0xc2/0x1c9 virtio_i2c_xfer+0x65/0x35c __i2c_transfer+0x429/0x57d i2c_transfer+0x115/0x134 i2cdev_ioctl_rdwr+0x16a/0x1de i2cdev_ioctl+0x247/0x2ed vfs_ioctl+0x21/0x30 sys_ioctl+0xb18/0xb41 Freed in virtio_i2c_xfer+0x32e/0x35c age=244 cpu=0 pid=29 kfree+0x1bd/0x1cc virtio_i2c_xfer+0x32e/0x35c __i2c_transfer+0x429/0x57d i2c_transfer+0x115/0x134 i2cdev_ioctl_rdwr+0x16a/0x1de i2cdev_ioctl+0x247/0x2ed vfs_ioctl+0x21/0x30 sys_ioctl+0xb18/0xb41 There is no simple fix for this (the driver would have to always create bounce buffers and hold on to them until the device eventually returns the buffers), so just disable the timeout support for now. Fixes: 3cfc88380413d20f ("i2c: virtio: add a virtio i2c frontend driver") Acked-by: Jie Deng <jie.deng@intel.com> Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Wolfram Sang <wsa@kernel.org>
2021-11-01i2c: virtio: Add support for zero-length requestsViresh Kumar
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
2021-08-19i2c: virtio: add a virtio i2c frontend driverJie Deng
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 <conghui.chen@intel.com> Signed-off-by: Conghui Chen <conghui.chen@intel.com> Signed-off-by: Jie Deng <jie.deng@intel.com> Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org> Tested-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Wolfram Sang <wsa@kernel.org>