kernel/linux.git/drivers/firewire/core-transaction.c, branch v6.6.131

firewire: core: implement variations to send request and wait for response with time stamp

2023-05-29T23:12:40+00:00

In the previous commit, the core function of Linux FireWire subsystem was changed for two cases to operate asynchronous transaction with or without time stamp. This commit changes kernel API for the two cases. Current kernel API, fw_send_request(), is changed to be static inline function to call __fw_send_request(), which receives two argument for union and flag of callback function. The new kernel API, fw_send_request_with_tstamp() is also added as static inline function, too. When calling, the two arguments are copied to internal structure, then used in softIRQ context. Link: https://lore.kernel.org/r/20230529113406.986289-7-o-takashi@sakamocchi.jp Signed-off-by: Takashi Sakamoto

firewire: core: use union for callback of transaction completion

2023-05-29T23:12:40+00:00

In 1394 OHCI, the OUTPUT_LAST descriptor of Asynchronous Transmit (AT) request context has timeStamp field, in which 1394 OHCI controller record the isochronous cycle when the packet was sent for the request subaction. Additionally, for the case of split transaction in IEEE 1394, Asynchronous Receive (AT) request context is used for response subaction to finish the transaction. The trailer quadlet of descriptor in the context has timeStamp field, in which 1394 OHCI controller records the isochronous cycle when the packet arrived. Current implementation of 1394 OHCI controller driver stores values of both fields to internal structure as time stamp, while Linux FireWire subsystem provides no way to access to it. When using asynchronous transaction service provided by the subsystem, callback function is passed to kernel API. The prototype of callback function has the lack of argument for the values. This commit adds a new callback function for the purpose. It has an additional argument to point to the constant array with two elements. For backward compatibility to kernel space, a new union is also adds to wrap two different prototype of callback function. The fw_transaction structure has the union as a member and a boolean flag to express which function callback is available. The core function is changed to handle the two cases; with or without time stamp. For the error path to process transaction, the isochronous cycle is computed by current value of CYCLE_TIMER register in 1394 OHCI controller. Especially for the case of timeout of split transaction, the expected isochronous cycle is computed. Link: https://lore.kernel.org/r/20230529113406.986289-6-o-takashi@sakamocchi.jp Signed-off-by: Takashi Sakamoto

firewire: cdev: obsolete NULL check to detect IEC 61883-1 FCP region

2023-01-23T08:17:44+00:00

In the character device, the listener to address space should distinguish whether the request is to IEC 61883-1 FCP region or not. The user space application needs to access to the object of request in enough later by read(2), while the core function releases the object of request in the FCP case after completing the callback to handler. The handler guarantees the access safe by some way. It's done by duplication of the object after NULL check to the request, since core function passes NULL in the FCP case. It's inconvenient since the object of request includes some helpful information. It's better to add another way to check whether the request is to FCP region or not. Conveniently the file of transaction layer includes local implementation for the purpose. This commit moves it to module local file and use it instead of the NULL check, then the result of check is stored to per-client data for the inbound transaction so that the result can be referred by later to release the data. Signed-off-by: Takashi Sakamoto Link: https://lore.kernel.org/r/20230120090344.296451-3-o-takashi@sakamocchi.jp Signed-off-by: Takashi Iwai

firewire: core: use kref structure to maintain lifetime of data for fw_request structure

2023-01-23T08:17:43+00:00

Developers have acknowledged that maintenance of lifetime for fw_transaction structure is effective when handling asynchronous transaction to IEC 61883-1 FCP region, since the core function allows multiples listeners to the region. Some of them needs to access to the payload of request in process context after the callback to listener, while the core function releases the object for the structure just after completing the callbacks to listeners. One of the listeners is character device. Current implementation of the character device duplicates the object for the payload of transaction, while it's a cost in kernel memory consumption. The lifetime management can reduce it. The typical way to maintain the lifetime is reference count. This commit uses kref structure as a first step for the purpose. Signed-off-by: Takashi Sakamoto Link: https://lore.kernel.org/r/20230120090344.296451-2-o-takashi@sakamocchi.jp Signed-off-by: Takashi Iwai

Merge branch 'for-linus' into for-next

2022-05-23T05:48:27+00:00

Merge for 5.18-rc1 Signed-off-by: Takashi Iwai

firewire: remove check of list iterator against head past the loop body

2022-04-25T06:01:08+00:00

When list_for_each_entry() completes the iteration over the whole list without breaking the loop, the iterator value will be a bogus pointer computed based on the head element. While it is safe to use the pointer to determine if it was computed based on the head element, either with list_entry_is_head() or &pos->member == head, using the iterator variable after the loop should be avoided. In preparation to limit the scope of a list iterator to the list traversal loop, use a dedicated pointer to point to the found element [1]. Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [1] Cc: Signed-off-by: Jakob Koschel Signed-off-by: Takashi Sakamoto Link: https://lore.kernel.org/r/20220409041243.603210-3-o-takashi@sakamocchi.jp Signed-off-by: Takashi Iwai

firewire: add kernel API to access packet structure in request structure for AR context

2022-04-05T16:23:05+00:00

In 1394 OHCI specification, descriptor of Asynchronous Receive DMA context has timeStamp field in its trailer quadlet. The field is written by the host controller for the time to receive asynchronous request subaction in isochronous cycle time. In Linux FireWire subsystem, the value of field is stored to fw_packet structure and copied to fw_request structure as the part. The fw_request structure is hidden from unit driver and passed as opaque pointer when calling registered handler. It's inconvenient to the unit driver which needs timestamp of packet. This commit adds kernel API to pick up timestamp from opaque pointer to fw_request structure. Signed-off-by: Takashi Sakamoto Link: https://lore.kernel.org/r/20220405072221.226217-4-o-takashi@sakamocchi.jp Signed-off-by: Takashi Iwai

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva

firewire: ohci: Replace zero-length array with flexible-array

2020-06-16T04:08:31+00:00

There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://github.com/KSPP/linux/issues/21 Signed-off-by: Gustavo A. R. Silva

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

2019-05-30T18:26:35+00:00

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Richard Fontana Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman