cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

lib.c (2132B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * miscellaneous helper functions
      4 *
      5 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
      6 */
      7
      8#include <linux/delay.h>
      9#include <linux/device.h>
     10#include <linux/firewire.h>
     11#include <linux/module.h>
     12#include <linux/slab.h>
     13#include "lib.h"
     14
     15#define ERROR_RETRY_DELAY_MS	20
     16
     17/**
     18 * snd_fw_transaction - send a request and wait for its completion
     19 * @unit: the driver's unit on the target device
     20 * @tcode: the transaction code
     21 * @offset: the address in the target's address space
     22 * @buffer: input/output data
     23 * @length: length of @buffer
     24 * @flags: use %FW_FIXED_GENERATION and add the generation value to attempt the
     25 *         request only in that generation; use %FW_QUIET to suppress error
     26 *         messages
     27 *
     28 * Submits an asynchronous request to the target device, and waits for the
     29 * response.  The node ID and the current generation are derived from @unit.
     30 * On a bus reset or an error, the transaction is retried a few times.
     31 * Returns zero on success, or a negative error code.
     32 */
     33int snd_fw_transaction(struct fw_unit *unit, int tcode,
     34		       u64 offset, void *buffer, size_t length,
     35		       unsigned int flags)
     36{
     37	struct fw_device *device = fw_parent_device(unit);
     38	int generation, rcode, tries = 0;
     39
     40	generation = flags & FW_GENERATION_MASK;
     41	for (;;) {
     42		if (!(flags & FW_FIXED_GENERATION)) {
     43			generation = device->generation;
     44			smp_rmb(); /* node_id vs. generation */
     45		}
     46		rcode = fw_run_transaction(device->card, tcode,
     47					   device->node_id, generation,
     48					   device->max_speed, offset,
     49					   buffer, length);
     50
     51		if (rcode == RCODE_COMPLETE)
     52			return 0;
     53
     54		if (rcode == RCODE_GENERATION && (flags & FW_FIXED_GENERATION))
     55			return -EAGAIN;
     56
     57		if (rcode_is_permanent_error(rcode) || ++tries >= 3) {
     58			if (!(flags & FW_QUIET))
     59				dev_err(&unit->device,
     60					"transaction failed: %s\n",
     61					fw_rcode_string(rcode));
     62			return -EIO;
     63		}
     64
     65		msleep(ERROR_RETRY_DELAY_MS);
     66	}
     67}
     68EXPORT_SYMBOL(snd_fw_transaction);
     69
     70MODULE_DESCRIPTION("FireWire audio helper functions");
     71MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
     72MODULE_LICENSE("GPL v2");