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Thomas Gleixner1a59d1b82019-05-27 08:55:05 +02001// SPDX-License-Identifier: GPL-2.0-or-later
Kristian Høgsbergc781c062007-05-07 20:33:32 -04002/*
3 * Copyright (C) 2005-2007 Kristian Hoegsberg <krh@bitplanet.net>
Kristian Høgsberg3038e352006-12-19 19:58:27 -05004 */
5
Stefan Richtere8ca9702009-06-04 21:09:38 +02006#include <linux/bug.h>
Stefan Richter459f7922008-05-24 16:50:22 +02007#include <linux/completion.h>
8#include <linux/crc-itu-t.h>
Kristian Høgsberg3038e352006-12-19 19:58:27 -05009#include <linux/device.h>
Stefan Richter459f7922008-05-24 16:50:22 +020010#include <linux/errno.h>
Stefan Richter77c9a5d2009-06-05 16:26:18 +020011#include <linux/firewire.h>
12#include <linux/firewire-constants.h>
Stefan Richtere8ca9702009-06-04 21:09:38 +020013#include <linux/jiffies.h>
14#include <linux/kernel.h>
Stefan Richter459f7922008-05-24 16:50:22 +020015#include <linux/kref.h>
Stefan Richtere8ca9702009-06-04 21:09:38 +020016#include <linux/list.h>
Stefan Richter459f7922008-05-24 16:50:22 +020017#include <linux/module.h>
Kristian Høgsberg6a5033b2007-05-07 20:33:33 -040018#include <linux/mutex.h>
Stefan Richtere8ca9702009-06-04 21:09:38 +020019#include <linux/spinlock.h>
Stefan Richtere8ca9702009-06-04 21:09:38 +020020#include <linux/workqueue.h>
Stefan Richter459f7922008-05-24 16:50:22 +020021
Arun Sharma600634972011-07-26 16:09:06 -070022#include <linux/atomic.h>
Stefan Richtere8ca9702009-06-04 21:09:38 +020023#include <asm/byteorder.h>
24
Stefan Richter77c9a5d2009-06-05 16:26:18 +020025#include "core.h"
Kristian Høgsberg3038e352006-12-19 19:58:27 -050026
Stefan Richter26b49502012-02-18 22:03:14 +010027#define define_fw_printk_level(func, kern_level) \
28void func(const struct fw_card *card, const char *fmt, ...) \
29{ \
30 struct va_format vaf; \
31 va_list args; \
32 \
33 va_start(args, fmt); \
34 vaf.fmt = fmt; \
35 vaf.va = &args; \
36 printk(kern_level KBUILD_MODNAME " %s: %pV", \
37 dev_name(card->device), &vaf); \
38 va_end(args); \
39}
40define_fw_printk_level(fw_err, KERN_ERR);
41define_fw_printk_level(fw_notice, KERN_NOTICE);
42
Stefan Richtercb7c96da32009-10-08 00:42:53 +020043int fw_compute_block_crc(__be32 *block)
Stefan Richter8e859732009-10-08 00:41:59 +020044{
45 int length;
46 u16 crc;
47
48 length = (be32_to_cpu(block[0]) >> 16) & 0xff;
49 crc = crc_itu_t(0, (u8 *)&block[1], length * 4);
50 *block |= cpu_to_be32(crc);
51
52 return length;
53}
54
Kristian Høgsberg6a5033b2007-05-07 20:33:33 -040055static DEFINE_MUTEX(card_mutex);
Kristian Høgsberg3038e352006-12-19 19:58:27 -050056static LIST_HEAD(card_list);
57
58static LIST_HEAD(descriptor_list);
59static int descriptor_count;
60
Stefan Richterfe242572009-10-08 00:42:27 +020061static __be32 tmp_config_rom[256];
Stefan Richtere3008392010-01-24 14:47:02 +010062/* ROM header, bus info block, root dir header, capabilities = 7 quadlets */
63static size_t config_rom_length = 1 + 4 + 1 + 1;
Stefan Richterfe242572009-10-08 00:42:27 +020064
Kristian Høgsberga77754a2007-05-07 20:33:35 -040065#define BIB_CRC(v) ((v) << 0)
66#define BIB_CRC_LENGTH(v) ((v) << 16)
67#define BIB_INFO_LENGTH(v) ((v) << 24)
Stefan Richteredd5bda2010-04-14 22:30:18 +020068#define BIB_BUS_NAME 0x31333934 /* "1394" */
Kristian Høgsberga77754a2007-05-07 20:33:35 -040069#define BIB_LINK_SPEED(v) ((v) << 0)
70#define BIB_GENERATION(v) ((v) << 4)
71#define BIB_MAX_ROM(v) ((v) << 8)
72#define BIB_MAX_RECEIVE(v) ((v) << 12)
73#define BIB_CYC_CLK_ACC(v) ((v) << 16)
74#define BIB_PMC ((1) << 27)
75#define BIB_BMC ((1) << 28)
76#define BIB_ISC ((1) << 29)
77#define BIB_CMC ((1) << 30)
Stefan Richteredd5bda2010-04-14 22:30:18 +020078#define BIB_IRMC ((1) << 31)
79#define NODE_CAPABILITIES 0x0c0083c0 /* per IEEE 1394 clause 8.3.2.6.5.2 */
Kristian Høgsberg3038e352006-12-19 19:58:27 -050080
Clemens Ladischdd5eeb92011-03-07 11:21:15 +010081/*
82 * IEEE-1394 specifies a default SPLIT_TIMEOUT value of 800 cycles (100 ms),
83 * but we have to make it longer because there are many devices whose firmware
84 * is just too slow for that.
85 */
86#define DEFAULT_SPLIT_TIMEOUT (2 * 8000)
87
Stefan Richter60445652011-01-15 18:19:48 +010088#define CANON_OUI 0x000085
89
Stefan Richtere3008392010-01-24 14:47:02 +010090static void generate_config_rom(struct fw_card *card, __be32 *config_rom)
Kristian Høgsberg3038e352006-12-19 19:58:27 -050091{
92 struct fw_descriptor *desc;
Stefan Richter8e859732009-10-08 00:41:59 +020093 int i, j, k, length;
Kristian Høgsberg3038e352006-12-19 19:58:27 -050094
Kristian Høgsbergc781c062007-05-07 20:33:32 -040095 /*
96 * Initialize contents of config rom buffer. On the OHCI
Stefan Richter5e20c282007-01-21 20:44:09 +010097 * controller, block reads to the config rom accesses the host
98 * memory, but quadlet read access the hardware bus info block
99 * registers. That's just crack, but it means we should make
Jay Fenlason2cc489c22008-10-22 15:59:42 -0400100 * sure the contents of bus info block in host memory matches
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400101 * the version stored in the OHCI registers.
102 */
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500103
Stefan Richter8e859732009-10-08 00:41:59 +0200104 config_rom[0] = cpu_to_be32(
105 BIB_CRC_LENGTH(4) | BIB_INFO_LENGTH(4) | BIB_CRC(0));
Stefan Richteredd5bda2010-04-14 22:30:18 +0200106 config_rom[1] = cpu_to_be32(BIB_BUS_NAME);
Stefan Richter8e859732009-10-08 00:41:59 +0200107 config_rom[2] = cpu_to_be32(
Kristian Høgsberga77754a2007-05-07 20:33:35 -0400108 BIB_LINK_SPEED(card->link_speed) |
109 BIB_GENERATION(card->config_rom_generation++ % 14 + 2) |
110 BIB_MAX_ROM(2) |
111 BIB_MAX_RECEIVE(card->max_receive) |
Stefan Richteredd5bda2010-04-14 22:30:18 +0200112 BIB_BMC | BIB_ISC | BIB_CMC | BIB_IRMC);
Stefan Richter8e859732009-10-08 00:41:59 +0200113 config_rom[3] = cpu_to_be32(card->guid >> 32);
114 config_rom[4] = cpu_to_be32(card->guid);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500115
116 /* Generate root directory. */
Stefan Richteredd5bda2010-04-14 22:30:18 +0200117 config_rom[6] = cpu_to_be32(NODE_CAPABILITIES);
Stefan Richter8e859732009-10-08 00:41:59 +0200118 i = 7;
119 j = 7 + descriptor_count;
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500120
121 /* Generate root directory entries for descriptors. */
122 list_for_each_entry (desc, &descriptor_list, link) {
Kristian Høgsberg937f6872007-03-07 12:12:36 -0500123 if (desc->immediate > 0)
Stefan Richter8e859732009-10-08 00:41:59 +0200124 config_rom[i++] = cpu_to_be32(desc->immediate);
125 config_rom[i] = cpu_to_be32(desc->key | (j - i));
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500126 i++;
127 j += desc->length;
128 }
129
130 /* Update root directory length. */
Stefan Richter8e859732009-10-08 00:41:59 +0200131 config_rom[5] = cpu_to_be32((i - 5 - 1) << 16);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500132
133 /* End of root directory, now copy in descriptors. */
134 list_for_each_entry (desc, &descriptor_list, link) {
Stefan Richter8e859732009-10-08 00:41:59 +0200135 for (k = 0; k < desc->length; k++)
136 config_rom[i + k] = cpu_to_be32(desc->data[k]);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500137 i += desc->length;
138 }
139
140 /* Calculate CRCs for all blocks in the config rom. This
141 * assumes that CRC length and info length are identical for
142 * the bus info block, which is always the case for this
143 * implementation. */
Kristian Høgsberge1755692007-05-07 20:33:31 -0400144 for (i = 0; i < j; i += length + 1)
Stefan Richtercb7c96da32009-10-08 00:42:53 +0200145 length = fw_compute_block_crc(config_rom + i);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500146
Stefan Richtere3008392010-01-24 14:47:02 +0100147 WARN_ON(j != config_rom_length);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500148}
149
Stefan Richter53dca512008-12-14 21:47:04 +0100150static void update_config_roms(void)
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500151{
152 struct fw_card *card;
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500153
154 list_for_each_entry (card, &card_list, link) {
Stefan Richtere3008392010-01-24 14:47:02 +0100155 generate_config_rom(card, tmp_config_rom);
156 card->driver->set_config_rom(card, tmp_config_rom,
157 config_rom_length);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500158 }
159}
160
Stefan Richtere3008392010-01-24 14:47:02 +0100161static size_t required_space(struct fw_descriptor *desc)
162{
163 /* descriptor + entry into root dir + optional immediate entry */
164 return desc->length + 1 + (desc->immediate > 0 ? 1 : 0);
165}
166
Stefan Richter53dca512008-12-14 21:47:04 +0100167int fw_core_add_descriptor(struct fw_descriptor *desc)
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500168{
169 size_t i;
Stefan Richtere3008392010-01-24 14:47:02 +0100170 int ret;
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500171
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400172 /*
173 * Check descriptor is valid; the length of all blocks in the
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500174 * descriptor has to add up to exactly the length of the
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400175 * block.
176 */
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500177 i = 0;
178 while (i < desc->length)
179 i += (desc->data[i] >> 16) + 1;
180
181 if (i != desc->length)
Kristian Høgsberg66dea3e2007-03-28 21:26:42 +0200182 return -EINVAL;
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500183
Kristian Høgsberg6a5033b2007-05-07 20:33:33 -0400184 mutex_lock(&card_mutex);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500185
Stefan Richtere3008392010-01-24 14:47:02 +0100186 if (config_rom_length + required_space(desc) > 256) {
187 ret = -EBUSY;
188 } else {
189 list_add_tail(&desc->link, &descriptor_list);
190 config_rom_length += required_space(desc);
Kristian Høgsberg937f6872007-03-07 12:12:36 -0500191 descriptor_count++;
Stefan Richtere3008392010-01-24 14:47:02 +0100192 if (desc->immediate > 0)
193 descriptor_count++;
194 update_config_roms();
195 ret = 0;
196 }
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500197
Kristian Høgsberg6a5033b2007-05-07 20:33:33 -0400198 mutex_unlock(&card_mutex);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500199
Stefan Richtere3008392010-01-24 14:47:02 +0100200 return ret;
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500201}
Jay Fenlasonc76acec2009-05-18 13:08:06 -0400202EXPORT_SYMBOL(fw_core_add_descriptor);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500203
Stefan Richter53dca512008-12-14 21:47:04 +0100204void fw_core_remove_descriptor(struct fw_descriptor *desc)
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500205{
Kristian Høgsberg6a5033b2007-05-07 20:33:33 -0400206 mutex_lock(&card_mutex);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500207
208 list_del(&desc->link);
Stefan Richtere3008392010-01-24 14:47:02 +0100209 config_rom_length -= required_space(desc);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500210 descriptor_count--;
Kristian Høgsberg937f6872007-03-07 12:12:36 -0500211 if (desc->immediate > 0)
212 descriptor_count--;
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500213 update_config_roms();
214
Kristian Høgsberg6a5033b2007-05-07 20:33:33 -0400215 mutex_unlock(&card_mutex);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500216}
Jay Fenlasonc76acec2009-05-18 13:08:06 -0400217EXPORT_SYMBOL(fw_core_remove_descriptor);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500218
Stefan Richter02d37be2010-07-08 16:09:06 +0200219static int reset_bus(struct fw_card *card, bool short_reset)
220{
221 int reg = short_reset ? 5 : 1;
222 int bit = short_reset ? PHY_BUS_SHORT_RESET : PHY_BUS_RESET;
223
224 return card->driver->update_phy_reg(card, reg, 0, bit);
225}
226
227void fw_schedule_bus_reset(struct fw_card *card, bool delayed, bool short_reset)
228{
229 /* We don't try hard to sort out requests of long vs. short resets. */
230 card->br_short = short_reset;
231
232 /* Use an arbitrary short delay to combine multiple reset requests. */
233 fw_card_get(card);
Stefan Richter105e53f2011-05-01 20:50:31 +0200234 if (!queue_delayed_work(fw_workqueue, &card->br_work,
Stefan Richter6ea9e7b2010-10-13 13:39:46 +0200235 delayed ? DIV_ROUND_UP(HZ, 100) : 0))
Stefan Richter02d37be2010-07-08 16:09:06 +0200236 fw_card_put(card);
237}
238EXPORT_SYMBOL(fw_schedule_bus_reset);
239
240static void br_work(struct work_struct *work)
241{
242 struct fw_card *card = container_of(work, struct fw_card, br_work.work);
243
244 /* Delay for 2s after last reset per IEEE 1394 clause 8.2.1. */
245 if (card->reset_jiffies != 0 &&
Clemens Ladische71084a2011-01-22 15:05:03 +0100246 time_before64(get_jiffies_64(), card->reset_jiffies + 2 * HZ)) {
Stefan Richter105e53f2011-05-01 20:50:31 +0200247 if (!queue_delayed_work(fw_workqueue, &card->br_work, 2 * HZ))
Stefan Richter02d37be2010-07-08 16:09:06 +0200248 fw_card_put(card);
249 return;
250 }
251
252 fw_send_phy_config(card, FW_PHY_CONFIG_NO_NODE_ID, card->generation,
253 FW_PHY_CONFIG_CURRENT_GAP_COUNT);
254 reset_bus(card, card->br_short);
255 fw_card_put(card);
256}
257
Stefan Richtercbae7872009-03-10 21:08:37 +0100258static void allocate_broadcast_channel(struct fw_card *card, int generation)
Jay Fenlason6104ee92009-02-23 15:59:34 -0500259{
Stefan Richtercbae7872009-03-10 21:08:37 +0100260 int channel, bandwidth = 0;
Jay Fenlason6104ee92009-02-23 15:59:34 -0500261
Clemens Ladische91b2782010-06-10 08:40:49 +0200262 if (!card->broadcast_channel_allocated) {
263 fw_iso_resource_manage(card, generation, 1ULL << 31,
Stefan Richterf30e6d32011-04-22 15:13:54 +0200264 &channel, &bandwidth, true);
Clemens Ladische91b2782010-06-10 08:40:49 +0200265 if (channel != 31) {
Stefan Richter26b49502012-02-18 22:03:14 +0100266 fw_notice(card, "failed to allocate broadcast channel\n");
Clemens Ladische91b2782010-06-10 08:40:49 +0200267 return;
268 }
Stefan Richter7889b602009-03-10 21:09:28 +0100269 card->broadcast_channel_allocated = true;
Jay Fenlason6104ee92009-02-23 15:59:34 -0500270 }
Clemens Ladische91b2782010-06-10 08:40:49 +0200271
272 device_for_each_child(card->device, (void *)(long)generation,
273 fw_device_set_broadcast_channel);
Jay Fenlason6104ee92009-02-23 15:59:34 -0500274}
Jay Fenlason6104ee92009-02-23 15:59:34 -0500275
Kristian Høgsberg83db8012007-01-26 00:37:50 -0500276static const char gap_count_table[] = {
277 63, 5, 7, 8, 10, 13, 16, 18, 21, 24, 26, 29, 32, 35, 37, 40
278};
279
Stefan Richter53dca512008-12-14 21:47:04 +0100280void fw_schedule_bm_work(struct fw_card *card, unsigned long delay)
Jay Fenlason0fa1986f2008-11-29 17:44:57 +0100281{
Jay Fenlason0fa1986f2008-11-29 17:44:57 +0100282 fw_card_get(card);
Stefan Richter02d37be2010-07-08 16:09:06 +0200283 if (!schedule_delayed_work(&card->bm_work, delay))
Jay Fenlason0fa1986f2008-11-29 17:44:57 +0100284 fw_card_put(card);
285}
286
Stefan Richter02d37be2010-07-08 16:09:06 +0200287static void bm_work(struct work_struct *work)
Kristian Høgsberg19a15b92006-12-19 19:58:31 -0500288{
Stefan Richter02d37be2010-07-08 16:09:06 +0200289 struct fw_card *card = container_of(work, struct fw_card, bm_work.work);
Stefan Richter10389532010-05-30 19:43:52 +0200290 struct fw_device *root_device, *irm_device;
Stefan Richtercbae7872009-03-10 21:08:37 +0100291 struct fw_node *root_node;
Stefan Richter250b2b62010-06-21 23:24:35 +0200292 int root_id, new_root_id, irm_id, bm_id, local_id;
Stefan Richtercbae7872009-03-10 21:08:37 +0100293 int gap_count, generation, grace, rcode;
Stefan Richter25b1c3d2008-03-24 20:57:12 +0100294 bool do_reset = false;
Stefan Richter62305822009-01-09 20:49:37 +0100295 bool root_device_is_running;
296 bool root_device_is_cmc;
Stefan Richter10389532010-05-30 19:43:52 +0200297 bool irm_is_1394_1995_only;
Stefan Richter60445652011-01-15 18:19:48 +0100298 bool keep_this_irm;
Stefan Richterf30e6d32011-04-22 15:13:54 +0200299 __be32 transaction_data[2];
Kristian Høgsberg19a15b92006-12-19 19:58:31 -0500300
Stefan Richterae948012010-06-21 23:23:52 +0200301 spin_lock_irq(&card->lock);
Stefan Richter15803472008-02-24 18:57:23 +0100302
Stefan Richtercbae7872009-03-10 21:08:37 +0100303 if (card->local_node == NULL) {
Stefan Richterae948012010-06-21 23:23:52 +0200304 spin_unlock_irq(&card->lock);
Jay Fenlason0fa1986f2008-11-29 17:44:57 +0100305 goto out_put_card;
Stefan Richter15803472008-02-24 18:57:23 +0100306 }
Kristian Høgsberg19a15b92006-12-19 19:58:31 -0500307
308 generation = card->generation;
Stefan Richter10389532010-05-30 19:43:52 +0200309
Stefan Richtercbae7872009-03-10 21:08:37 +0100310 root_node = card->root_node;
311 fw_node_get(root_node);
Stefan Richter15803472008-02-24 18:57:23 +0100312 root_device = root_node->data;
Stefan Richter62305822009-01-09 20:49:37 +0100313 root_device_is_running = root_device &&
314 atomic_read(&root_device->state) == FW_DEVICE_RUNNING;
315 root_device_is_cmc = root_device && root_device->cmc;
Stefan Richter10389532010-05-30 19:43:52 +0200316
317 irm_device = card->irm_node->data;
318 irm_is_1394_1995_only = irm_device && irm_device->config_rom &&
319 (irm_device->config_rom[2] & 0x000000f0) == 0;
320
Stefan Richter60445652011-01-15 18:19:48 +0100321 /* Canon MV5i works unreliably if it is not root node. */
322 keep_this_irm = irm_device && irm_device->config_rom &&
323 irm_device->config_rom[3] >> 8 == CANON_OUI;
324
Stefan Richtercbae7872009-03-10 21:08:37 +0100325 root_id = root_node->node_id;
326 irm_id = card->irm_node->node_id;
327 local_id = card->local_node->node_id;
Stefan Richtere1dc7ca2009-03-10 21:07:46 +0100328
Clemens Ladische71084a2011-01-22 15:05:03 +0100329 grace = time_after64(get_jiffies_64(),
330 card->reset_jiffies + DIV_ROUND_UP(HZ, 8));
Stefan Richtere1dc7ca2009-03-10 21:07:46 +0100331
Clemens Ladisch7e0e314f2010-06-10 08:37:15 +0200332 if ((is_next_generation(generation, card->bm_generation) &&
333 !card->bm_abdicate) ||
Kristian Høgsberg931c4832007-01-26 00:38:45 -0500334 (card->bm_generation != generation && grace)) {
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400335 /*
336 * This first step is to figure out who is IRM and
Kristian Høgsberg931c4832007-01-26 00:38:45 -0500337 * then try to become bus manager. If the IRM is not
338 * well defined (e.g. does not have an active link
339 * layer or does not responds to our lock request, we
340 * will have to do a little vigilante bus management.
341 * In that case, we do a goto into the gap count logic
342 * so that when we do the reset, we still optimize the
343 * gap count. That could well save a reset in the
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400344 * next generation.
345 */
Kristian Høgsberg931c4832007-01-26 00:38:45 -0500346
Stefan Richtercbae7872009-03-10 21:08:37 +0100347 if (!card->irm_node->link_on) {
348 new_root_id = local_id;
Stefan Richter26b49502012-02-18 22:03:14 +0100349 fw_notice(card, "%s, making local node (%02x) root\n",
Stefan Richter10389532010-05-30 19:43:52 +0200350 "IRM has link off", new_root_id);
351 goto pick_me;
352 }
353
Stefan Richter60445652011-01-15 18:19:48 +0100354 if (irm_is_1394_1995_only && !keep_this_irm) {
Stefan Richter10389532010-05-30 19:43:52 +0200355 new_root_id = local_id;
Stefan Richter26b49502012-02-18 22:03:14 +0100356 fw_notice(card, "%s, making local node (%02x) root\n",
Stefan Richter10389532010-05-30 19:43:52 +0200357 "IRM is not 1394a compliant", new_root_id);
Kristian Høgsberg931c4832007-01-26 00:38:45 -0500358 goto pick_me;
359 }
360
Stefan Richterf30e6d32011-04-22 15:13:54 +0200361 transaction_data[0] = cpu_to_be32(0x3f);
362 transaction_data[1] = cpu_to_be32(local_id);
Kristian Høgsberg931c4832007-01-26 00:38:45 -0500363
Stefan Richterae948012010-06-21 23:23:52 +0200364 spin_unlock_irq(&card->lock);
Kristian Høgsberg931c4832007-01-26 00:38:45 -0500365
Jay Fenlason1e119fa2008-07-20 14:20:53 +0200366 rcode = fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
367 irm_id, generation, SCODE_100,
368 CSR_REGISTER_BASE + CSR_BUS_MANAGER_ID,
Stefan Richterf30e6d32011-04-22 15:13:54 +0200369 transaction_data, 8);
Kristian Høgsberg931c4832007-01-26 00:38:45 -0500370
Jay Fenlason1e119fa2008-07-20 14:20:53 +0200371 if (rcode == RCODE_GENERATION)
372 /* Another bus reset, BM work has been rescheduled. */
Stefan Richter15803472008-02-24 18:57:23 +0100373 goto out;
Kristian Høgsberg931c4832007-01-26 00:38:45 -0500374
Stefan Richterf30e6d32011-04-22 15:13:54 +0200375 bm_id = be32_to_cpu(transaction_data[0]);
Stefan Richtercbae7872009-03-10 21:08:37 +0100376
Stefan Richter250b2b62010-06-21 23:24:35 +0200377 spin_lock_irq(&card->lock);
378 if (rcode == RCODE_COMPLETE && generation == card->generation)
379 card->bm_node_id =
380 bm_id == 0x3f ? local_id : 0xffc0 | bm_id;
381 spin_unlock_irq(&card->lock);
382
383 if (rcode == RCODE_COMPLETE && bm_id != 0x3f) {
Stefan Richtercbae7872009-03-10 21:08:37 +0100384 /* Somebody else is BM. Only act as IRM. */
385 if (local_id == irm_id)
386 allocate_broadcast_channel(card, generation);
387
Stefan Richter15803472008-02-24 18:57:23 +0100388 goto out;
Jay Fenlason6104ee92009-02-23 15:59:34 -0500389 }
Kristian Høgsberg931c4832007-01-26 00:38:45 -0500390
Clemens Ladischbda3b8a2010-06-10 08:23:28 +0200391 if (rcode == RCODE_SEND_ERROR) {
392 /*
393 * We have been unable to send the lock request due to
394 * some local problem. Let's try again later and hope
395 * that the problem has gone away by then.
396 */
397 fw_schedule_bm_work(card, DIV_ROUND_UP(HZ, 8));
398 goto out;
399 }
400
Stefan Richterae948012010-06-21 23:23:52 +0200401 spin_lock_irq(&card->lock);
Jay Fenlason1e119fa2008-07-20 14:20:53 +0200402
Stefan Richter60445652011-01-15 18:19:48 +0100403 if (rcode != RCODE_COMPLETE && !keep_this_irm) {
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400404 /*
405 * The lock request failed, maybe the IRM
Kristian Høgsberg931c4832007-01-26 00:38:45 -0500406 * isn't really IRM capable after all. Let's
407 * do a bus reset and pick the local node as
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400408 * root, and thus, IRM.
409 */
Stefan Richtercbae7872009-03-10 21:08:37 +0100410 new_root_id = local_id;
Clemens Ladisch3b00b002012-04-11 17:38:47 +0200411 fw_notice(card, "BM lock failed (%s), making local node (%02x) root\n",
412 fw_rcode_string(rcode), new_root_id);
Kristian Høgsberg931c4832007-01-26 00:38:45 -0500413 goto pick_me;
414 }
415 } else if (card->bm_generation != generation) {
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400416 /*
Stefan Richtere1dc7ca2009-03-10 21:07:46 +0100417 * We weren't BM in the last generation, and the last
418 * bus reset is less than 125ms ago. Reschedule this job.
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400419 */
Stefan Richterae948012010-06-21 23:23:52 +0200420 spin_unlock_irq(&card->lock);
Stefan Richtere1dc7ca2009-03-10 21:07:46 +0100421 fw_schedule_bm_work(card, DIV_ROUND_UP(HZ, 8));
Stefan Richter15803472008-02-24 18:57:23 +0100422 goto out;
Kristian Høgsberg931c4832007-01-26 00:38:45 -0500423 }
424
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400425 /*
426 * We're bus manager for this generation, so next step is to
Kristian Høgsberg931c4832007-01-26 00:38:45 -0500427 * make sure we have an active cycle master and do gap count
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400428 * optimization.
429 */
Kristian Høgsberg931c4832007-01-26 00:38:45 -0500430 card->bm_generation = generation;
Kristian Høgsberg19a15b92006-12-19 19:58:31 -0500431
Stefan Richter15803472008-02-24 18:57:23 +0100432 if (root_device == NULL) {
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400433 /*
434 * Either link_on is false, or we failed to read the
435 * config rom. In either case, pick another root.
436 */
Stefan Richtercbae7872009-03-10 21:08:37 +0100437 new_root_id = local_id;
Stefan Richter62305822009-01-09 20:49:37 +0100438 } else if (!root_device_is_running) {
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400439 /*
440 * If we haven't probed this device yet, bail out now
441 * and let's try again once that's done.
442 */
Stefan Richterae948012010-06-21 23:23:52 +0200443 spin_unlock_irq(&card->lock);
Stefan Richter15803472008-02-24 18:57:23 +0100444 goto out;
Stefan Richter62305822009-01-09 20:49:37 +0100445 } else if (root_device_is_cmc) {
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400446 /*
Clemens Ladischc374ab42010-06-10 08:41:51 +0200447 * We will send out a force root packet for this
448 * node as part of the gap count optimization.
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400449 */
Kristian Høgsberg931c4832007-01-26 00:38:45 -0500450 new_root_id = root_id;
Kristian Høgsberg83db8012007-01-26 00:37:50 -0500451 } else {
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400452 /*
453 * Current root has an active link layer and we
Kristian Høgsberg19a15b92006-12-19 19:58:31 -0500454 * successfully read the config rom, but it's not
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400455 * cycle master capable.
456 */
Stefan Richtercbae7872009-03-10 21:08:37 +0100457 new_root_id = local_id;
Kristian Høgsberg83db8012007-01-26 00:37:50 -0500458 }
Kristian Høgsberg19a15b92006-12-19 19:58:31 -0500459
Kristian Høgsberg931c4832007-01-26 00:38:45 -0500460 pick_me:
Stefan Richter24d40122007-06-18 19:44:12 +0200461 /*
462 * Pick a gap count from 1394a table E-1. The table doesn't cover
463 * the typically much larger 1394b beta repeater delays though.
464 */
465 if (!card->beta_repeaters_present &&
Stefan Richter15803472008-02-24 18:57:23 +0100466 root_node->max_hops < ARRAY_SIZE(gap_count_table))
467 gap_count = gap_count_table[root_node->max_hops];
Kristian Høgsberg83db8012007-01-26 00:37:50 -0500468 else
469 gap_count = 63;
470
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400471 /*
Stefan Richter25b1c3d2008-03-24 20:57:12 +0100472 * Finally, figure out if we should do a reset or not. If we have
473 * done less than 5 resets with the same physical topology and we
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400474 * have either a new root or a new gap count setting, let's do it.
475 */
Kristian Høgsberg83db8012007-01-26 00:37:50 -0500476
Kristian Høgsberg931c4832007-01-26 00:38:45 -0500477 if (card->bm_retries++ < 5 &&
478 (card->gap_count != gap_count || new_root_id != root_id))
Stefan Richter25b1c3d2008-03-24 20:57:12 +0100479 do_reset = true;
Kristian Høgsberg19a15b92006-12-19 19:58:31 -0500480
Stefan Richterae948012010-06-21 23:23:52 +0200481 spin_unlock_irq(&card->lock);
Kristian Høgsberg19a15b92006-12-19 19:58:31 -0500482
Kristian Høgsberg83db8012007-01-26 00:37:50 -0500483 if (do_reset) {
Stefan Richter26b49502012-02-18 22:03:14 +0100484 fw_notice(card, "phy config: new root=%x, gap_count=%d\n",
485 new_root_id, gap_count);
Kristian Høgsberg931c4832007-01-26 00:38:45 -0500486 fw_send_phy_config(card, new_root_id, generation, gap_count);
Stefan Richter02d37be2010-07-08 16:09:06 +0200487 reset_bus(card, true);
Stefan Richtercbae7872009-03-10 21:08:37 +0100488 /* Will allocate broadcast channel after the reset. */
Clemens Ladischc374ab42010-06-10 08:41:51 +0200489 goto out;
Kristian Høgsberg19a15b92006-12-19 19:58:31 -0500490 }
Jay Fenlason6104ee92009-02-23 15:59:34 -0500491
Clemens Ladischc374ab42010-06-10 08:41:51 +0200492 if (root_device_is_cmc) {
493 /*
494 * Make sure that the cycle master sends cycle start packets.
495 */
Stefan Richterf30e6d32011-04-22 15:13:54 +0200496 transaction_data[0] = cpu_to_be32(CSR_STATE_BIT_CMSTR);
Clemens Ladischc374ab42010-06-10 08:41:51 +0200497 rcode = fw_run_transaction(card, TCODE_WRITE_QUADLET_REQUEST,
498 root_id, generation, SCODE_100,
499 CSR_REGISTER_BASE + CSR_STATE_SET,
Stefan Richterf30e6d32011-04-22 15:13:54 +0200500 transaction_data, 4);
Clemens Ladischc374ab42010-06-10 08:41:51 +0200501 if (rcode == RCODE_GENERATION)
502 goto out;
503 }
504
505 if (local_id == irm_id)
506 allocate_broadcast_channel(card, generation);
507
Stefan Richter15803472008-02-24 18:57:23 +0100508 out:
Stefan Richter15803472008-02-24 18:57:23 +0100509 fw_node_put(root_node);
Jay Fenlason0fa1986f2008-11-29 17:44:57 +0100510 out_put_card:
511 fw_card_put(card);
Kristian Høgsberg19a15b92006-12-19 19:58:31 -0500512}
513
Stefan Richter53dca512008-12-14 21:47:04 +0100514void fw_card_initialize(struct fw_card *card,
515 const struct fw_card_driver *driver,
516 struct device *device)
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500517{
Kristian Høgsbergbbf19db2007-02-06 14:49:38 -0500518 static atomic_t index = ATOMIC_INIT(-1);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500519
Kristian Høgsbergbbf19db2007-02-06 14:49:38 -0500520 card->index = atomic_inc_return(&index);
Stefan Richter5e20c282007-01-21 20:44:09 +0100521 card->driver = driver;
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500522 card->device = device;
Stefan Richter5e20c282007-01-21 20:44:09 +0100523 card->current_tlabel = 0;
524 card->tlabel_mask = 0;
Clemens Ladischdd5eeb92011-03-07 11:21:15 +0100525 card->split_timeout_hi = DEFAULT_SPLIT_TIMEOUT / 8000;
526 card->split_timeout_lo = (DEFAULT_SPLIT_TIMEOUT % 8000) << 19;
527 card->split_timeout_cycles = DEFAULT_SPLIT_TIMEOUT;
528 card->split_timeout_jiffies =
529 DIV_ROUND_UP(DEFAULT_SPLIT_TIMEOUT * HZ, 8000);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500530 card->color = 0;
Stefan Richtere534fe12008-05-24 16:41:09 +0200531 card->broadcast_channel = BROADCAST_CHANNEL_INITIAL;
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500532
Stefan Richter459f7922008-05-24 16:50:22 +0200533 kref_init(&card->kref);
534 init_completion(&card->done);
Stefan Richter5e20c282007-01-21 20:44:09 +0100535 INIT_LIST_HEAD(&card->transaction_list);
Stefan Richterbf54e142010-07-16 22:25:51 +0200536 INIT_LIST_HEAD(&card->phy_receiver_list);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500537 spin_lock_init(&card->lock);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500538
539 card->local_node = NULL;
540
Stefan Richter02d37be2010-07-08 16:09:06 +0200541 INIT_DELAYED_WORK(&card->br_work, br_work);
542 INIT_DELAYED_WORK(&card->bm_work, bm_work);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500543}
544EXPORT_SYMBOL(fw_card_initialize);
545
Stefan Richter53dca512008-12-14 21:47:04 +0100546int fw_card_add(struct fw_card *card,
547 u32 max_receive, u32 link_speed, u64 guid)
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500548{
Stefan Richtere1eff7a2009-02-03 17:55:19 +0100549 int ret;
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500550
551 card->max_receive = max_receive;
552 card->link_speed = link_speed;
553 card->guid = guid;
554
Kristian Høgsberg6a5033b2007-05-07 20:33:33 -0400555 mutex_lock(&card_mutex);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500556
Stefan Richtere3008392010-01-24 14:47:02 +0100557 generate_config_rom(card, tmp_config_rom);
558 ret = card->driver->enable(card, tmp_config_rom, config_rom_length);
Stefan Richterb171e202009-09-06 18:50:29 +0200559 if (ret == 0)
560 list_add_tail(&card->link, &card_list);
561
562 mutex_unlock(&card_mutex);
Stefan Richtere1eff7a2009-02-03 17:55:19 +0100563
564 return ret;
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500565}
566EXPORT_SYMBOL(fw_card_add);
567
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400568/*
Stefan Richterd645f4d2009-06-16 19:15:25 +0200569 * The next few functions implement a dummy driver that is used once a card
570 * driver shuts down an fw_card. This allows the driver to cleanly unload,
571 * as all IO to the card will be handled (and failed) by the dummy driver
572 * instead of calling into the module. Only functions for iso context
573 * shutdown still need to be provided by the card driver.
Stefan Richter20802222010-08-01 12:23:14 +0200574 *
575 * .read/write_csr() should never be called anymore after the dummy driver
576 * was bound since they are only used within request handler context.
577 * .set_config_rom() is never called since the card is taken out of card_list
578 * before switching to the dummy driver.
Kristian Høgsbergc781c062007-05-07 20:33:32 -0400579 */
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500580
Stefan Richter02d37be2010-07-08 16:09:06 +0200581static int dummy_read_phy_reg(struct fw_card *card, int address)
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500582{
Stefan Richter02d37be2010-07-08 16:09:06 +0200583 return -ENODEV;
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500584}
585
Stefan Richter53dca512008-12-14 21:47:04 +0100586static int dummy_update_phy_reg(struct fw_card *card, int address,
587 int clear_bits, int set_bits)
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500588{
589 return -ENODEV;
590}
591
Stefan Richter53dca512008-12-14 21:47:04 +0100592static void dummy_send_request(struct fw_card *card, struct fw_packet *packet)
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500593{
Stefan Richter18d0cdf2010-07-18 12:44:01 +0200594 packet->callback(packet, card, RCODE_CANCELLED);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500595}
596
Stefan Richter53dca512008-12-14 21:47:04 +0100597static void dummy_send_response(struct fw_card *card, struct fw_packet *packet)
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500598{
Stefan Richter18d0cdf2010-07-18 12:44:01 +0200599 packet->callback(packet, card, RCODE_CANCELLED);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500600}
601
Stefan Richter53dca512008-12-14 21:47:04 +0100602static int dummy_cancel_packet(struct fw_card *card, struct fw_packet *packet)
Kristian Høgsberg730c32f2007-02-06 14:49:32 -0500603{
604 return -ENOENT;
605}
606
Stefan Richter53dca512008-12-14 21:47:04 +0100607static int dummy_enable_phys_dma(struct fw_card *card,
608 int node_id, int generation)
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500609{
610 return -ENODEV;
611}
612
Stefan Richter20802222010-08-01 12:23:14 +0200613static struct fw_iso_context *dummy_allocate_iso_context(struct fw_card *card,
614 int type, int channel, size_t header_size)
615{
616 return ERR_PTR(-ENODEV);
617}
618
Hector Martine70b6692022-04-05 16:22:19 +0900619static u32 dummy_read_csr(struct fw_card *card, int csr_offset)
620{
621 return 0;
622}
623
624static void dummy_write_csr(struct fw_card *card, int csr_offset, u32 value)
625{
626}
627
Stefan Richter20802222010-08-01 12:23:14 +0200628static int dummy_start_iso(struct fw_iso_context *ctx,
629 s32 cycle, u32 sync, u32 tags)
630{
631 return -ENODEV;
632}
633
634static int dummy_set_iso_channels(struct fw_iso_context *ctx, u64 *channels)
635{
636 return -ENODEV;
637}
638
639static int dummy_queue_iso(struct fw_iso_context *ctx, struct fw_iso_packet *p,
640 struct fw_iso_buffer *buffer, unsigned long payload)
641{
642 return -ENODEV;
643}
644
Clemens Ladisch13882a82011-05-02 09:33:56 +0200645static void dummy_flush_queue_iso(struct fw_iso_context *ctx)
646{
647}
648
Clemens Ladischd1bbd202012-03-18 19:06:39 +0100649static int dummy_flush_iso_completions(struct fw_iso_context *ctx)
650{
651 return -ENODEV;
652}
653
Stefan Richterd645f4d2009-06-16 19:15:25 +0200654static const struct fw_card_driver dummy_driver_template = {
Stefan Richter20802222010-08-01 12:23:14 +0200655 .read_phy_reg = dummy_read_phy_reg,
656 .update_phy_reg = dummy_update_phy_reg,
657 .send_request = dummy_send_request,
658 .send_response = dummy_send_response,
659 .cancel_packet = dummy_cancel_packet,
660 .enable_phys_dma = dummy_enable_phys_dma,
Hector Martine70b6692022-04-05 16:22:19 +0900661 .read_csr = dummy_read_csr,
662 .write_csr = dummy_write_csr,
Stefan Richter20802222010-08-01 12:23:14 +0200663 .allocate_iso_context = dummy_allocate_iso_context,
664 .start_iso = dummy_start_iso,
665 .set_iso_channels = dummy_set_iso_channels,
666 .queue_iso = dummy_queue_iso,
Clemens Ladisch13882a82011-05-02 09:33:56 +0200667 .flush_queue_iso = dummy_flush_queue_iso,
Clemens Ladischd1bbd202012-03-18 19:06:39 +0100668 .flush_iso_completions = dummy_flush_iso_completions,
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500669};
670
Stefan Richter53dca512008-12-14 21:47:04 +0100671void fw_card_release(struct kref *kref)
Stefan Richter459f7922008-05-24 16:50:22 +0200672{
673 struct fw_card *card = container_of(kref, struct fw_card, kref);
674
675 complete(&card->done);
676}
Chris Bootfc5f80b2012-02-01 22:36:02 +0000677EXPORT_SYMBOL_GPL(fw_card_release);
Stefan Richter459f7922008-05-24 16:50:22 +0200678
Stefan Richter53dca512008-12-14 21:47:04 +0100679void fw_core_remove_card(struct fw_card *card)
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500680{
Stefan Richterd645f4d2009-06-16 19:15:25 +0200681 struct fw_card_driver dummy_driver = dummy_driver_template;
Niels Dosschea7ecbe92022-04-09 13:12:43 +0900682 unsigned long flags;
Stefan Richterd645f4d2009-06-16 19:15:25 +0200683
Marc Butlerecab4132007-03-23 10:24:02 -0600684 card->driver->update_phy_reg(card, 4,
685 PHY_LINK_ACTIVE | PHY_CONTENDER, 0);
Stefan Richter02d37be2010-07-08 16:09:06 +0200686 fw_schedule_bus_reset(card, false, true);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500687
Kristian Høgsberg6a5033b2007-05-07 20:33:33 -0400688 mutex_lock(&card_mutex);
Stefan Richtere747a5c2009-01-24 20:35:38 +0100689 list_del_init(&card->link);
Kristian Høgsberg6a5033b2007-05-07 20:33:33 -0400690 mutex_unlock(&card_mutex);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500691
Stefan Richterd645f4d2009-06-16 19:15:25 +0200692 /* Switch off most of the card driver interface. */
693 dummy_driver.free_iso_context = card->driver->free_iso_context;
694 dummy_driver.stop_iso = card->driver->stop_iso;
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500695 card->driver = &dummy_driver;
696
Niels Dosschea7ecbe92022-04-09 13:12:43 +0900697 spin_lock_irqsave(&card->lock, flags);
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500698 fw_destroy_nodes(card);
Niels Dosschea7ecbe92022-04-09 13:12:43 +0900699 spin_unlock_irqrestore(&card->lock, flags);
Stefan Richter459f7922008-05-24 16:50:22 +0200700
701 /* Wait for all users, especially device workqueue jobs, to finish. */
702 fw_card_put(card);
703 wait_for_completion(&card->done);
Stefan Richter8a2d9ed2007-08-21 01:05:14 +0200704
Stefan Richter1e8afea2008-07-12 14:51:18 +0200705 WARN_ON(!list_empty(&card->transaction_list));
Kristian Høgsberg3038e352006-12-19 19:58:27 -0500706}
707EXPORT_SYMBOL(fw_core_remove_card);
Takashi Sakamotobaa914c2022-04-05 16:22:20 +0900708
709/**
710 * fw_card_read_cycle_time: read from Isochronous Cycle Timer Register of 1394 OHCI in MMIO region
711 * for controller card.
712 * @card: The instance of card for 1394 OHCI controller.
713 * @cycle_time: The mutual reference to value of cycle time for the read operation.
714 *
715 * Read value from Isochronous Cycle Timer Register of 1394 OHCI in MMIO region for the given
716 * controller card. This function accesses the region without any lock primitives or IRQ mask.
717 * When returning successfully, the content of @value argument has value aligned to host endianness,
718 * formetted by CYCLE_TIME CSR Register of IEEE 1394 std.
719 *
720 * Context: Any context.
721 * Return:
722 * * 0 - Read successfully.
723 * * -ENODEV - The controller is unavailable due to being removed or unbound.
724 */
725int fw_card_read_cycle_time(struct fw_card *card, u32 *cycle_time)
726{
727 if (card->driver->read_csr == dummy_read_csr)
728 return -ENODEV;
729
730 // It's possible to switch to dummy driver between the above and the below. This is the best
731 // effort to return -ENODEV.
732 *cycle_time = card->driver->read_csr(card, CSR_CYCLE_TIME);
733 return 0;
734}
735EXPORT_SYMBOL_GPL(fw_card_read_cycle_time);