1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Basic HP/COMPAQ MSA 1000 support. This is only needed if your HW cannot be
4 * upgraded.
5 *
6 * Copyright (C) 2006 Red Hat, Inc. All rights reserved.
7 * Copyright (C) 2006 Mike Christie
8 * Copyright (C) 2008 Hannes Reinecke <hare@suse.de>
9 */
10
11 #include <linux/slab.h>
12 #include <linux/module.h>
13 #include <scsi/scsi.h>
14 #include <scsi/scsi_dbg.h>
15 #include <scsi/scsi_eh.h>
16 #include <scsi/scsi_dh.h>
17
18 #define HP_SW_NAME "hp_sw"
19
20 #define HP_SW_TIMEOUT (60 * HZ)
21 #define HP_SW_RETRIES 3
22
23 #define HP_SW_PATH_UNINITIALIZED -1
24 #define HP_SW_PATH_ACTIVE 0
25 #define HP_SW_PATH_PASSIVE 1
26
27 struct hp_sw_dh_data {
28 int path_state;
29 int retries;
30 int retry_cnt;
31 struct scsi_device *sdev;
32 };
33
34 static int hp_sw_start_stop(struct hp_sw_dh_data *);
35
36 /*
37 * tur_done - Handle TEST UNIT READY return status
38 * @sdev: sdev the command has been sent to
39 * @errors: blk error code
40 *
41 * Returns SCSI_DH_DEV_OFFLINED if the sdev is on the passive path
42 */
tur_done(struct scsi_device * sdev,struct hp_sw_dh_data * h,struct scsi_sense_hdr * sshdr)43 static int tur_done(struct scsi_device *sdev, struct hp_sw_dh_data *h,
44 struct scsi_sense_hdr *sshdr)
45 {
46 int ret = SCSI_DH_IO;
47
48 switch (sshdr->sense_key) {
49 case UNIT_ATTENTION:
50 ret = SCSI_DH_IMM_RETRY;
51 break;
52 case NOT_READY:
53 if (sshdr->asc == 0x04 && sshdr->ascq == 2) {
54 /*
55 * LUN not ready - Initialization command required
56 *
57 * This is the passive path
58 */
59 h->path_state = HP_SW_PATH_PASSIVE;
60 ret = SCSI_DH_OK;
61 break;
62 }
63 fallthrough;
64 default:
65 sdev_printk(KERN_WARNING, sdev,
66 "%s: sending tur failed, sense %x/%x/%x\n",
67 HP_SW_NAME, sshdr->sense_key, sshdr->asc,
68 sshdr->ascq);
69 break;
70 }
71 return ret;
72 }
73
74 /*
75 * hp_sw_tur - Send TEST UNIT READY
76 * @sdev: sdev command should be sent to
77 *
78 * Use the TEST UNIT READY command to determine
79 * the path state.
80 */
hp_sw_tur(struct scsi_device * sdev,struct hp_sw_dh_data * h)81 static int hp_sw_tur(struct scsi_device *sdev, struct hp_sw_dh_data *h)
82 {
83 unsigned char cmd[6] = { TEST_UNIT_READY };
84 struct scsi_sense_hdr sshdr;
85 int ret = SCSI_DH_OK, res;
86 blk_opf_t opf = REQ_OP_DRV_IN | REQ_FAILFAST_DEV |
87 REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER;
88 const struct scsi_exec_args exec_args = {
89 .sshdr = &sshdr,
90 };
91
92 retry:
93 res = scsi_execute_cmd(sdev, cmd, opf, NULL, 0, HP_SW_TIMEOUT,
94 HP_SW_RETRIES, &exec_args);
95 if (res) {
96 if (scsi_sense_valid(&sshdr))
97 ret = tur_done(sdev, h, &sshdr);
98 else {
99 sdev_printk(KERN_WARNING, sdev,
100 "%s: sending tur failed with %x\n",
101 HP_SW_NAME, res);
102 ret = SCSI_DH_IO;
103 }
104 } else {
105 h->path_state = HP_SW_PATH_ACTIVE;
106 ret = SCSI_DH_OK;
107 }
108 if (ret == SCSI_DH_IMM_RETRY)
109 goto retry;
110
111 return ret;
112 }
113
114 /*
115 * hp_sw_start_stop - Send START STOP UNIT command
116 * @sdev: sdev command should be sent to
117 *
118 * Sending START STOP UNIT activates the SP.
119 */
hp_sw_start_stop(struct hp_sw_dh_data * h)120 static int hp_sw_start_stop(struct hp_sw_dh_data *h)
121 {
122 unsigned char cmd[6] = { START_STOP, 0, 0, 0, 1, 0 };
123 struct scsi_sense_hdr sshdr;
124 struct scsi_device *sdev = h->sdev;
125 int res, rc = SCSI_DH_OK;
126 int retry_cnt = HP_SW_RETRIES;
127 blk_opf_t opf = REQ_OP_DRV_IN | REQ_FAILFAST_DEV |
128 REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER;
129 const struct scsi_exec_args exec_args = {
130 .sshdr = &sshdr,
131 };
132
133 retry:
134 res = scsi_execute_cmd(sdev, cmd, opf, NULL, 0, HP_SW_TIMEOUT,
135 HP_SW_RETRIES, &exec_args);
136 if (res) {
137 if (!scsi_sense_valid(&sshdr)) {
138 sdev_printk(KERN_WARNING, sdev,
139 "%s: sending start_stop_unit failed, "
140 "no sense available\n", HP_SW_NAME);
141 return SCSI_DH_IO;
142 }
143 switch (sshdr.sense_key) {
144 case NOT_READY:
145 if (sshdr.asc == 0x04 && sshdr.ascq == 3) {
146 /*
147 * LUN not ready - manual intervention required
148 *
149 * Switch-over in progress, retry.
150 */
151 if (--retry_cnt)
152 goto retry;
153 rc = SCSI_DH_RETRY;
154 break;
155 }
156 fallthrough;
157 default:
158 sdev_printk(KERN_WARNING, sdev,
159 "%s: sending start_stop_unit failed, "
160 "sense %x/%x/%x\n", HP_SW_NAME,
161 sshdr.sense_key, sshdr.asc, sshdr.ascq);
162 rc = SCSI_DH_IO;
163 }
164 }
165 return rc;
166 }
167
hp_sw_prep_fn(struct scsi_device * sdev,struct request * req)168 static blk_status_t hp_sw_prep_fn(struct scsi_device *sdev, struct request *req)
169 {
170 struct hp_sw_dh_data *h = sdev->handler_data;
171
172 if (h->path_state != HP_SW_PATH_ACTIVE) {
173 req->rq_flags |= RQF_QUIET;
174 return BLK_STS_IOERR;
175 }
176
177 return BLK_STS_OK;
178 }
179
180 /*
181 * hp_sw_activate - Activate a path
182 * @sdev: sdev on the path to be activated
183 *
184 * The HP Active/Passive firmware is pretty simple;
185 * the passive path reports NOT READY with sense codes
186 * 0x04/0x02; a START STOP UNIT command will then
187 * activate the passive path (and deactivate the
188 * previously active one).
189 */
hp_sw_activate(struct scsi_device * sdev,activate_complete fn,void * data)190 static int hp_sw_activate(struct scsi_device *sdev,
191 activate_complete fn, void *data)
192 {
193 int ret = SCSI_DH_OK;
194 struct hp_sw_dh_data *h = sdev->handler_data;
195
196 ret = hp_sw_tur(sdev, h);
197
198 if (ret == SCSI_DH_OK && h->path_state == HP_SW_PATH_PASSIVE)
199 ret = hp_sw_start_stop(h);
200
201 if (fn)
202 fn(data, ret);
203 return 0;
204 }
205
hp_sw_bus_attach(struct scsi_device * sdev)206 static int hp_sw_bus_attach(struct scsi_device *sdev)
207 {
208 struct hp_sw_dh_data *h;
209 int ret;
210
211 h = kzalloc(sizeof(*h), GFP_KERNEL);
212 if (!h)
213 return SCSI_DH_NOMEM;
214 h->path_state = HP_SW_PATH_UNINITIALIZED;
215 h->retries = HP_SW_RETRIES;
216 h->sdev = sdev;
217
218 ret = hp_sw_tur(sdev, h);
219 if (ret != SCSI_DH_OK)
220 goto failed;
221 if (h->path_state == HP_SW_PATH_UNINITIALIZED) {
222 ret = SCSI_DH_NOSYS;
223 goto failed;
224 }
225
226 sdev_printk(KERN_INFO, sdev, "%s: attached to %s path\n",
227 HP_SW_NAME, h->path_state == HP_SW_PATH_ACTIVE?
228 "active":"passive");
229
230 sdev->handler_data = h;
231 return SCSI_DH_OK;
232 failed:
233 kfree(h);
234 return ret;
235 }
236
hp_sw_bus_detach(struct scsi_device * sdev)237 static void hp_sw_bus_detach( struct scsi_device *sdev )
238 {
239 kfree(sdev->handler_data);
240 sdev->handler_data = NULL;
241 }
242
243 static struct scsi_device_handler hp_sw_dh = {
244 .name = HP_SW_NAME,
245 .module = THIS_MODULE,
246 .attach = hp_sw_bus_attach,
247 .detach = hp_sw_bus_detach,
248 .activate = hp_sw_activate,
249 .prep_fn = hp_sw_prep_fn,
250 };
251
hp_sw_init(void)252 static int __init hp_sw_init(void)
253 {
254 return scsi_register_device_handler(&hp_sw_dh);
255 }
256
hp_sw_exit(void)257 static void __exit hp_sw_exit(void)
258 {
259 scsi_unregister_device_handler(&hp_sw_dh);
260 }
261
262 module_init(hp_sw_init);
263 module_exit(hp_sw_exit);
264
265 MODULE_DESCRIPTION("HP Active/Passive driver");
266 MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu");
267 MODULE_LICENSE("GPL");
268