From dd05add7b2b6004c5fa3a1f276f56d8668f86b65 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Sat, 26 Sep 2026 19:20:30 -0300 Subject: netfs: zero the tail of a short DIO/unbuffered read The buffered read collector zero-fills the tail of a short read that stops below the inode's i_size (netfs_clear_unread()), so a read that races an extending write still returns the expected number of bytes. The non-buffered collector path does no such thing: it just records how much was transferred. Add the same zero-fill for the non-buffered case, gated on NETFS_SREQ_CLEAR_TAIL: a subreq's source sets that flag when a short result from it is known to be safe to treat as a hole, as opposed to NETFS_SREQ_HIT_EOF, which means the read genuinely ran off the end of the file and should be reported short as-is. Only CLEAR_TAIL should zero-fill here; a real EOF must stay a real short read. No source currently sets CLEAR_TAIL on an unbuffered/DIO subrequest, so this is inert on its own -- a following change teaches cifs to set it in the one case that needs it. Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item") Reviewed-by: David Howells Reviewed-by: Namjae Jeon Signed-off-by: Paulo Alcantara Cc: Christian Brauner Cc: Matthew Wilcox Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Bharath SM Cc: stable@vger.kernel.org --- drivers/gpu/host1x/mipi.c | 195 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 195 insertions(+) create mode 100644 drivers/gpu/host1x/mipi.c (limited to 'drivers/gpu/host1x/mipi.c') diff --git a/drivers/gpu/host1x/mipi.c b/drivers/gpu/host1x/mipi.c new file mode 100644 index 000000000..988681423 --- /dev/null +++ b/drivers/gpu/host1x/mipi.c @@ -0,0 +1,195 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2013 NVIDIA Corporation + * Copyright (C) 2025 Svyatoslav Ryhel + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* only need to support one provider */ +static struct { + struct device_node *np; + const struct tegra_mipi_ops *ops; +} provider; + +/** + * tegra_mipi_enable - Enable the Tegra MIPI calibration device. + * @device: Handle to the Tegra MIPI calibration device. + * + * This calls the enable sequence for the Tegra MIPI calibration device. + * + * Returns 0 on success or a negative error code on failure. + */ +int tegra_mipi_enable(struct tegra_mipi_device *device) +{ + if (device->ops->enable) + return device->ops->enable(device); + + return 0; +} +EXPORT_SYMBOL(tegra_mipi_enable); + +/** + * tegra_mipi_disable - Disable the Tegra MIPI calibration device. + * @device: Handle to the Tegra MIPI calibration device. + * + * This calls the disable sequence for the Tegra MIPI calibration device. + * + * Returns 0 on success or a negative error code on failure. + */ +int tegra_mipi_disable(struct tegra_mipi_device *device) +{ + if (device->ops->disable) + return device->ops->disable(device); + + return 0; +} +EXPORT_SYMBOL(tegra_mipi_disable); + +/** + * tegra_mipi_start_calibration - Start the Tegra MIPI calibration sequence. + * @device: Handle to the Tegra MIPI calibration device. + * + * This initiates the calibration of CSI/DSI interfaces via the Tegra MIPI + * calibration device. + * + * Returns 0 on success or a negative error code on failure. + */ +int tegra_mipi_start_calibration(struct tegra_mipi_device *device) +{ + if (device->ops->start_calibration) + return device->ops->start_calibration(device); + + return 0; +} +EXPORT_SYMBOL(tegra_mipi_start_calibration); + +/** + * tegra_mipi_finish_calibration - Finish the Tegra MIPI calibration sequence. + * @device: Handle to the Tegra MIPI calibration device. + * + * This completes the calibration of CSI/DSI interfaces via the Tegra MIPI + * calibration device. + * + * Returns 0 on success or a negative error code on failure. + */ +int tegra_mipi_finish_calibration(struct tegra_mipi_device *device) +{ + if (device->ops->finish_calibration) + return device->ops->finish_calibration(device); + + return 0; +} +EXPORT_SYMBOL(tegra_mipi_finish_calibration); + +/** + * tegra_mipi_request - Request a Tegra MIPI calibration device. + * @device: Handle of the device requesting the MIPI calibration function. + * @np: Device node pointer of the device requesting the MIPI calibration + * function. + * + * This function requests a reference to a Tegra MIPI calibration device. + * + * Returns a pointer to the Tegra MIPI calibration device on success, + * or an ERR_PTR-encoded error code on failure. + */ +struct tegra_mipi_device *tegra_mipi_request(struct device *device, + struct device_node *np) +{ + struct tegra_mipi_device *mipidev; + struct of_phandle_args args; + int err; + + err = of_parse_phandle_with_args(np, "nvidia,mipi-calibrate", + "#nvidia,mipi-calibrate-cells", 0, + &args); + if (err < 0) + return ERR_PTR(err); + + if (provider.np != args.np) { + err = -ENODEV; + goto out; + } + + mipidev = kzalloc_obj(*mipidev); + if (!mipidev) { + err = -ENOMEM; + goto out; + } + + mipidev->pdev = of_find_device_by_node(args.np); + if (!mipidev->pdev) { + err = -ENODEV; + goto free; + } + + of_node_put(args.np); + + mipidev->ops = provider.ops; + mipidev->pads = args.args[0]; + + return mipidev; + +free: + kfree(mipidev); +out: + of_node_put(args.np); + return ERR_PTR(err); +} +EXPORT_SYMBOL(tegra_mipi_request); + +/** + * tegra_mipi_free - Free a Tegra MIPI calibration device. + * @mipidev: Handle to the Tegra MIPI calibration device. + * + * This function releases a reference to a Tegra MIPI calibration device + * previously requested by tegra_mipi_request(). + */ +void tegra_mipi_free(struct tegra_mipi_device *mipidev) +{ + platform_device_put(mipidev->pdev); + kfree(mipidev); +} +EXPORT_SYMBOL(tegra_mipi_free); + +static void tegra_mipi_remove_provider(void *data) +{ + provider.np = NULL; + provider.ops = NULL; +} + +/** + * devm_tegra_mipi_add_provider - Managed registration of a Tegra MIPI + * calibration function provider. + * @device: Handle to the device providing the MIPI calibration function. + * @np: Device node pointer of the device providing the MIPI calibration + * function. + * @ops: Operations supported by the MIPI calibration device. + * + * This registers a device that provides MIPI calibration functions. + * For Tegra20 and Tegra30, this is the CSI block, while Tegra114 and + * newer SoC generations have a dedicated hardware block for these + * functions. + * + * Returns 0 on success or a negative error code on failure. + */ +int devm_tegra_mipi_add_provider(struct device *device, struct device_node *np, + const struct tegra_mipi_ops *ops) +{ + if (provider.np) + return -EBUSY; + + provider.np = np; + provider.ops = ops; + + return devm_add_action_or_reset(device, tegra_mipi_remove_provider, NULL); +} +EXPORT_SYMBOL(devm_tegra_mipi_add_provider); -- cgit v1.3.1