cregit-Linux how code gets into the kernel

Release 4.7 sound/firewire/fcp.c

Directory: sound/firewire
/*
 * Function Control Protocol (IEC 61883-1) helper functions
 *
 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
 * Licensed under the terms of the GNU General Public License, version 2.
 */

#include <linux/device.h>
#include <linux/firewire.h>
#include <linux/firewire-constants.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/delay.h>
#include "fcp.h"
#include "lib.h"
#include "amdtp-stream.h"


#define CTS_AVC 0x00


#define ERROR_RETRIES	3

#define ERROR_DELAY_MS	5

#define FCP_TIMEOUT_MS	125


int avc_general_set_sig_fmt(struct fw_unit *unit, unsigned int rate, enum avc_general_plug_dir dir, unsigned short pid) { unsigned int sfc; u8 *buf; bool flag; int err; flag = false; for (sfc = 0; sfc < CIP_SFC_COUNT; sfc++) { if (amdtp_rate_table[sfc] == rate) { flag = true; break; } } if (!flag) return -EINVAL; buf = kzalloc(8, GFP_KERNEL); if (buf == NULL) return -ENOMEM; buf[0] = 0x00; /* AV/C CONTROL */ buf[1] = 0xff; /* UNIT */ if (dir == AVC_GENERAL_PLUG_DIR_IN) buf[2] = 0x19; /* INPUT PLUG SIGNAL FORMAT */ else buf[2] = 0x18; /* OUTPUT PLUG SIGNAL FORMAT */ buf[3] = 0xff & pid; /* plug id */ buf[4] = 0x90; /* EOH_1, Form_1, FMT. AM824 */ buf[5] = 0x07 & sfc; /* FDF-hi. AM824, frequency */ buf[6] = 0xff; /* FDF-mid. AM824, SYT hi (not used)*/ buf[7] = 0xff; /* FDF-low. AM824, SYT lo (not used) */ /* do transaction and check buf[1-5] are the same against command */ err = fcp_avc_transaction(unit, buf, 8, buf, 8, BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(5)); if (err >= 0 && err < 8) err = -EIO; else if (buf[0] == 0x08) /* NOT IMPLEMENTED */ err = -ENOSYS; else if (buf[0] == 0x0a) /* REJECTED */ err = -EINVAL; if (err < 0) goto end; err = 0; end: kfree(buf); return err; }

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EXPORT_SYMBOL(avc_general_set_sig_fmt);
int avc_general_get_sig_fmt(struct fw_unit *unit, unsigned int *rate, enum avc_general_plug_dir dir, unsigned short pid) { unsigned int sfc; u8 *buf; int err; buf = kzalloc(8, GFP_KERNEL); if (buf == NULL) return -ENOMEM; buf[0] = 0x01; /* AV/C STATUS */ buf[1] = 0xff; /* Unit */ if (dir == AVC_GENERAL_PLUG_DIR_IN) buf[2] = 0x19; /* INPUT PLUG SIGNAL FORMAT */ else buf[2] = 0x18; /* OUTPUT PLUG SIGNAL FORMAT */ buf[3] = 0xff & pid; /* plug id */ buf[4] = 0x90; /* EOH_1, Form_1, FMT. AM824 */ buf[5] = 0xff; /* FDF-hi. AM824, frequency */ buf[6] = 0xff; /* FDF-mid. AM824, SYT hi (not used) */ buf[7] = 0xff; /* FDF-low. AM824, SYT lo (not used) */ /* do transaction and check buf[1-4] are the same against command */ err = fcp_avc_transaction(unit, buf, 8, buf, 8, BIT(1) | BIT(2) | BIT(3) | BIT(4)); if (err >= 0 && err < 8) err = -EIO; else if (buf[0] == 0x08) /* NOT IMPLEMENTED */ err = -ENOSYS; else if (buf[0] == 0x0a) /* REJECTED */ err = -EINVAL; else if (buf[0] == 0x0b) /* IN TRANSITION */ err = -EAGAIN; if (err < 0) goto end; /* check sfc field and pick up rate */ sfc = 0x07 & buf[5]; if (sfc >= CIP_SFC_COUNT) { err = -EAGAIN; /* also in transition */ goto end; } *rate = amdtp_rate_table[sfc]; err = 0; end: kfree(buf); return err; }

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EXPORT_SYMBOL(avc_general_get_sig_fmt);
int avc_general_get_plug_info(struct fw_unit *unit, unsigned int subunit_type, unsigned int subunit_id, unsigned int subfunction, u8 info[AVC_PLUG_INFO_BUF_BYTES]) { u8 *buf; int err; /* extended subunit in spec.4.2 is not supported */ if ((subunit_type == 0x1E) || (subunit_id == 5)) return -EINVAL; buf = kzalloc(8, GFP_KERNEL); if (buf == NULL) return -ENOMEM; buf[0] = 0x01; /* AV/C STATUS */ /* UNIT or Subunit, Functionblock */ buf[1] = ((subunit_type & 0x1f) << 3) | (subunit_id & 0x7); buf[2] = 0x02; /* PLUG INFO */ buf[3] = 0xff & subfunction; err = fcp_avc_transaction(unit, buf, 8, buf, 8, BIT(1) | BIT(2)); if (err >= 0 && err < 8) err = -EIO; else if (buf[0] == 0x08) /* NOT IMPLEMENTED */ err = -ENOSYS; else if (buf[0] == 0x0a) /* REJECTED */ err = -EINVAL; else if (buf[0] == 0x0b) /* IN TRANSITION */ err = -EAGAIN; if (err < 0) goto end; info[0] = buf[4]; info[1] = buf[5]; info[2] = buf[6]; info[3] = buf[7]; err = 0; end: kfree(buf); return err; }

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EXPORT_SYMBOL(avc_general_get_plug_info); static DEFINE_SPINLOCK(transactions_lock); static LIST_HEAD(transactions); enum fcp_state { STATE_PENDING, STATE_BUS_RESET, STATE_COMPLETE, STATE_DEFERRED, }; struct fcp_transaction { struct list_head list; struct fw_unit *unit; void *response_buffer; unsigned int response_size; unsigned int response_match_bytes; enum fcp_state state; wait_queue_head_t wait; bool deferrable; }; /** * fcp_avc_transaction - send an AV/C command and wait for its response * @unit: a unit on the target device * @command: a buffer containing the command frame; must be DMA-able * @command_size: the size of @command * @response: a buffer for the response frame * @response_size: the maximum size of @response * @response_match_bytes: a bitmap specifying the bytes used to detect the * correct response frame * * This function sends a FCP command frame to the target and waits for the * corresponding response frame to be returned. * * Because it is possible for multiple FCP transactions to be active at the * same time, the correct response frame is detected by the value of certain * bytes. These bytes must be set in @response before calling this function, * and the corresponding bits must be set in @response_match_bytes. * * @command and @response can point to the same buffer. * * Returns the actual size of the response frame, or a negative error code. */
int fcp_avc_transaction(struct fw_unit *unit, const void *command, unsigned int command_size, void *response, unsigned int response_size, unsigned int response_match_bytes) { struct fcp_transaction t; int tcode, ret, tries = 0; t.unit = unit; t.response_buffer = response; t.response_size = response_size; t.response_match_bytes = response_match_bytes; t.state = STATE_PENDING; init_waitqueue_head(&t.wait); if (*(const u8 *)command == 0x00 || *(const u8 *)command == 0x03) t.deferrable = true; spin_lock_irq(&transactions_lock); list_add_tail(&t.list, &transactions); spin_unlock_irq(&transactions_lock); for (;;) { tcode = command_size == 4 ? TCODE_WRITE_QUADLET_REQUEST : TCODE_WRITE_BLOCK_REQUEST; ret = snd_fw_transaction(t.unit, tcode, CSR_REGISTER_BASE + CSR_FCP_COMMAND, (void *)command, command_size, 0); if (ret < 0) break; deferred: wait_event_timeout(t.wait, t.state != STATE_PENDING, msecs_to_jiffies(FCP_TIMEOUT_MS)); if (t.state == STATE_DEFERRED) { /* * 'AV/C General Specification' define no time limit * on command completion once an INTERIM response has * been sent. but we promise to finish this function * for a caller. Here we use FCP_TIMEOUT_MS for next * interval. This is not in the specification. */ t.state = STATE_PENDING; goto deferred; } else if (t.state == STATE_COMPLETE) { ret = t.response_size; break; } else if (t.state == STATE_BUS_RESET) { msleep(ERROR_DELAY_MS); } else if (++tries >= ERROR_RETRIES) { dev_err(&t.unit->device, "FCP command timed out\n"); ret = -EIO; break; } } spin_lock_irq(&transactions_lock); list_del(&t.list); spin_unlock_irq(&transactions_lock); return ret; }

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EXPORT_SYMBOL(fcp_avc_transaction); /** * fcp_bus_reset - inform the target handler about a bus reset * @unit: the unit that might be used by fcp_avc_transaction() * * This function must be called from the driver's .update handler to inform * the FCP transaction handler that a bus reset has happened. Any pending FCP * transactions are retried. */
void fcp_bus_reset(struct fw_unit *unit) { struct fcp_transaction *t; spin_lock_irq(&transactions_lock); list_for_each_entry(t, &transactions, list) { if (t->unit == unit && (t->state == STATE_PENDING || t->state == STATE_DEFERRED)) { t->state = STATE_BUS_RESET; wake_up(&t->wait); } } spin_unlock_irq(&transactions_lock); }

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clemens ladischclemens ladisch6789.33%150.00%
takashi sakamototakashi sakamoto810.67%150.00%
Total75100.00%2100.00%

EXPORT_SYMBOL(fcp_bus_reset); /* checks whether the response matches the masked bytes in response_buffer */
static bool is_matching_response(struct fcp_transaction *transaction, const void *response, size_t length) { const u8 *p1, *p2; unsigned int mask, i; p1 = response; p2 = transaction->response_buffer; mask = transaction->response_match_bytes; for (i = 0; ; ++i) { if ((mask & 1) && p1[i] != p2[i]) return false; mask >>= 1; if (!mask) return true; if (--length == 0) return false; } }

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clemens ladischclemens ladisch104100.00%1100.00%
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static void fcp_response(struct fw_card *card, struct fw_request *request, int tcode, int destination, int source, int generation, unsigned long long offset, void *data, size_t length, void *callback_data) { struct fcp_transaction *t; unsigned long flags; if (length < 1 || (*(const u8 *)data & 0xf0) != CTS_AVC) return; spin_lock_irqsave(&transactions_lock, flags); list_for_each_entry(t, &transactions, list) { struct fw_device *device = fw_parent_device(t->unit); if (device->card != card || device->generation != generation) continue; smp_rmb(); /* node_id vs. generation */ if (device->node_id != source) continue; if (t->state == STATE_PENDING && is_matching_response(t, data, length)) { if (t->deferrable && *(const u8 *)data == 0x0f) { t->state = STATE_DEFERRED; } else { t->state = STATE_COMPLETE; t->response_size = min_t(unsigned int, length, t->response_size); memcpy(t->response_buffer, data, t->response_size); } wake_up(&t->wait); } } spin_unlock_irqrestore(&transactions_lock, flags); }

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clemens ladischclemens ladisch19485.84%150.00%
takashi sakamototakashi sakamoto3214.16%150.00%
Total226100.00%2100.00%

static struct fw_address_handler response_register_handler = { .length = 0x200, .address_callback = fcp_response, };
static int __init fcp_module_init(void) { static const struct fw_address_region response_register_region = { .start = CSR_REGISTER_BASE + CSR_FCP_RESPONSE, .end = CSR_REGISTER_BASE + CSR_FCP_END, }; fw_core_add_address_handler(&response_register_handler, &response_register_region); return 0; }

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static void __exit fcp_module_exit(void) { WARN_ON(!list_empty(&transactions)); fw_core_remove_address_handler(&response_register_handler); }

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module_init(fcp_module_init); module_exit(fcp_module_exit);

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takashi sakamototakashi sakamoto97353.88%457.14%
clemens ladischclemens ladisch83045.96%228.57%
stephen rothwellstephen rothwell30.17%114.29%
Total1806100.00%7100.00%
Directory: sound/firewire
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