1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
|
/*
* Greybus gbuf handling
*
* Copyright 2014 Google Inc.
*
* Released under the GPLv2 only.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/types.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include "greybus.h"
static void cport_process_event(struct work_struct *work);
static struct kmem_cache *gbuf_head_cache;
/* Workqueue to handle Greybus buffer completions. */
static struct workqueue_struct *gbuf_workqueue;
static struct gbuf *__alloc_gbuf(struct greybus_module *gmod,
u16 cport_id,
gbuf_complete_t complete,
gfp_t gfp_mask,
void *context)
{
struct gbuf *gbuf;
gbuf = kmem_cache_zalloc(gbuf_head_cache, gfp_mask);
if (!gbuf)
return NULL;
kref_init(&gbuf->kref);
gbuf->gmod = gmod;
gbuf->cport_id = cport_id;
INIT_WORK(&gbuf->event, cport_process_event);
gbuf->complete = complete;
gbuf->context = context;
return gbuf;
}
/**
* greybus_alloc_gbuf - allocate a greybus buffer
*
* @gmod: greybus device that wants to allocate this
* @cport: cport to send the data to
* @complete: callback when the gbuf is finished with
* @size: size of the buffer
* @gfp_mask: allocation mask
* @context: context added to the gbuf by the driver
*
* TODO: someday it will be nice to handle DMA, but for now, due to the
* architecture we are stuck with, the greybus core has to allocate the buffer
* that the driver can then fill up with the data to be sent out. Curse
* hardware designers for this issue...
*/
struct gbuf *greybus_alloc_gbuf(struct greybus_module *gmod,
u16 cport_id,
gbuf_complete_t complete,
unsigned int size,
gfp_t gfp_mask,
void *context)
{
struct gbuf *gbuf;
int retval;
gbuf = __alloc_gbuf(gmod, cport_id, complete, gfp_mask, context);
if (!gbuf)
return NULL;
gbuf->direction = GBUF_DIRECTION_OUT;
/* Host controller specific allocation for the actual buffer */
retval = gbuf->gmod->hd->driver->alloc_gbuf_data(gbuf, size, gfp_mask);
if (retval) {
greybus_free_gbuf(gbuf);
return NULL;
}
return gbuf;
}
EXPORT_SYMBOL_GPL(greybus_alloc_gbuf);
static DEFINE_MUTEX(gbuf_mutex);
static void free_gbuf(struct kref *kref)
{
struct gbuf *gbuf = container_of(kref, struct gbuf, kref);
/* If the direction is "out" then the host controller frees the data */
if (gbuf->direction == GBUF_DIRECTION_OUT) {
gbuf->gmod->hd->driver->free_gbuf_data(gbuf);
} else {
/* we "own" this in data, so free it ourselves */
kfree(gbuf->transfer_buffer);
}
kmem_cache_free(gbuf_head_cache, gbuf);
}
void greybus_free_gbuf(struct gbuf *gbuf)
{
/* drop the reference count and get out of here */
kref_put_mutex(&gbuf->kref, free_gbuf, &gbuf_mutex);
}
EXPORT_SYMBOL_GPL(greybus_free_gbuf);
struct gbuf *greybus_get_gbuf(struct gbuf *gbuf)
{
mutex_lock(&gbuf_mutex);
kref_get(&gbuf->kref);
mutex_unlock(&gbuf_mutex);
return gbuf;
}
EXPORT_SYMBOL_GPL(greybus_get_gbuf);
int greybus_submit_gbuf(struct gbuf *gbuf, gfp_t gfp_mask)
{
return gbuf->gmod->hd->driver->submit_gbuf(gbuf, gbuf->gmod->hd, gfp_mask);
}
int greybus_kill_gbuf(struct gbuf *gbuf)
{
// FIXME - implement
return -ENOMEM;
}
static void cport_process_event(struct work_struct *work)
{
struct gbuf *gbuf = container_of(work, struct gbuf, event);
/* Call the completion handler, then drop our reference */
gbuf->complete(gbuf);
greybus_put_gbuf(gbuf);
}
#define MAX_CPORTS 1024
struct gb_cport_handler {
gbuf_complete_t handler;
u16 cport_id;
struct greybus_module *gmod;
void *context;
};
static struct gb_cport_handler cport_handler[MAX_CPORTS];
// FIXME - use a lock for this list of handlers, but really, for now we don't
// need it, we don't have a dynamic system...
int gb_register_cport_complete(struct greybus_module *gmod,
gbuf_complete_t handler, u16 cport_id,
void *context)
{
if (cport_handler[cport_id].handler)
return -EINVAL;
cport_handler[cport_id].context = context;
cport_handler[cport_id].gmod = gmod;
cport_handler[cport_id].cport_id = cport_id;
cport_handler[cport_id].handler = handler;
return 0;
}
void gb_deregister_cport_complete(u16 cport_id)
{
cport_handler[cport_id].handler = NULL;
}
void greybus_cport_in(struct greybus_host_device *hd, u16 cport_id,
u8 *data, size_t length)
{
struct gb_cport_handler *ch;
struct gbuf *gbuf;
/* first check to see if we have a cport handler for this cport */
ch = &cport_handler[cport_id];
if (!ch->handler) {
/* Ugh, drop the data on the floor, after logging it... */
dev_err(hd->parent,
"Received data for cport %d, but no handler!\n",
cport_id);
return;
}
gbuf = __alloc_gbuf(ch->gmod, ch->cport_id, ch->handler, GFP_ATOMIC,
ch->context);
if (!gbuf) {
/* Again, something bad went wrong, log it... */
pr_err("can't allocate gbuf???\n");
return;
}
gbuf->hdpriv = hd;
gbuf->direction = GBUF_DIRECTION_IN;
/*
* FIXME:
* Very dumb copy data method for now, if this is slow (odds are it will
* be, we should move to a model where the hd "owns" all buffers, but we
* want something up and working first for now.
*/
gbuf->transfer_buffer = kmalloc(length, GFP_ATOMIC);
if (!gbuf->transfer_buffer) {
kfree(gbuf);
return;
}
memcpy(gbuf->transfer_buffer, data, length);
gbuf->transfer_buffer_length = length;
gbuf->actual_length = length;
queue_work(gbuf_workqueue, &gbuf->event);
}
EXPORT_SYMBOL_GPL(greybus_cport_in);
/* Can be called in interrupt context, do the work and get out of here */
void greybus_gbuf_finished(struct gbuf *gbuf)
{
queue_work(gbuf_workqueue, &gbuf->event);
}
EXPORT_SYMBOL_GPL(greybus_gbuf_finished);
int gb_gbuf_init(void)
{
gbuf_workqueue = alloc_workqueue("greybus_gbuf", 0, 1);
if (!gbuf_workqueue)
return -ENOMEM;
gbuf_head_cache = kmem_cache_create("gbuf_head_cache",
sizeof(struct gbuf), 0, 0, NULL);
return 0;
}
void gb_gbuf_exit(void)
{
destroy_workqueue(gbuf_workqueue);
kmem_cache_destroy(gbuf_head_cache);
}
|