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Inaky Perez-Gonzalez11a7d0e2008-12-20 16:57:50 -08001/*
2 * Intel Wireless WiMAX Connection 2400m
3 * USB-specific i2400m driver definitions
4 *
5 *
6 * Copyright (C) 2007-2008 Intel Corporation. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * * Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * * Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in
16 * the documentation and/or other materials provided with the
17 * distribution.
18 * * Neither the name of Intel Corporation nor the names of its
19 * contributors may be used to endorse or promote products derived
20 * from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
25 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
26 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
27 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
28 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
32 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 *
34 *
35 * Intel Corporation <linux-wimax@intel.com>
36 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
37 * Yanir Lubetkin <yanirx.lubetkin@intel.com>
38 * - Initial implementation
39 *
40 *
41 * This driver implements the bus-specific part of the i2400m for
42 * USB. Check i2400m.h for a generic driver description.
43 *
44 * ARCHITECTURE
45 *
46 * This driver listens to notifications sent from the notification
47 * endpoint (in usb-notif.c); when data is ready to read, the code in
48 * there schedules a read from the device (usb-rx.c) and then passes
49 * the data to the generic RX code (rx.c).
50 *
51 * When the generic driver needs to send data (network or control), it
52 * queues up in the TX FIFO (tx.c) and that will notify the driver
53 * through the i2400m->bus_tx_kick() callback
54 * (usb-tx.c:i2400mu_bus_tx_kick) which will send the items in the
55 * FIFO queue.
56 *
57 * This driver, as well, implements the USB-specific ops for the generic
58 * driver to be able to setup/teardown communication with the device
59 * [i2400m_bus_dev_start() and i2400m_bus_dev_stop()], reseting the
60 * device [i2400m_bus_reset()] and performing firmware upload
61 * [i2400m_bus_bm_cmd() and i2400_bus_bm_wait_for_ack()].
62 */
63
64#ifndef __I2400M_USB_H__
65#define __I2400M_USB_H__
66
67#include "i2400m.h"
68#include <linux/kthread.h>
69
70
71/*
72 * Error Density Count: cheapo error density (over time) counter
73 *
74 * Originally by Reinette Chatre <reinette.chatre@intel.com>
75 *
76 * Embed an 'struct edc' somewhere. Each time there is a soft or
77 * retryable error, call edc_inc() and check if the error top
78 * watermark has been reached.
79 */
80enum {
81 EDC_MAX_ERRORS = 10,
82 EDC_ERROR_TIMEFRAME = HZ,
83};
84
85/* error density counter */
86struct edc {
87 unsigned long timestart;
88 u16 errorcount;
89};
90
91static inline void edc_init(struct edc *edc)
92{
93 edc->timestart = jiffies;
94}
95
96/**
97 * edc_inc - report a soft error and check if we are over the watermark
98 *
99 * @edc: pointer to error density counter.
100 * @max_err: maximum number of errors we can accept over the timeframe
101 * @timeframe: lenght of the timeframe (in jiffies).
102 *
103 * Returns: !0 1 if maximum acceptable errors per timeframe has been
104 * exceeded. 0 otherwise.
105 *
106 * This is way to determine if the number of acceptable errors per time
107 * period has been exceeded. It is not accurate as there are cases in which
108 * this scheme will not work, for example if there are periodic occurences
109 * of errors that straddle updates to the start time. This scheme is
110 * sufficient for our usage.
111 *
112 * To use, embed a 'struct edc' somewhere, initialize it with
113 * edc_init() and when an error hits:
114 *
115 * if (do_something_fails_with_a_soft_error) {
116 * if (edc_inc(&my->edc, MAX_ERRORS, MAX_TIMEFRAME))
117 * Ops, hard error, do something about it
118 * else
119 * Retry or ignore, depending on whatever
120 * }
121 */
122static inline int edc_inc(struct edc *edc, u16 max_err, u16 timeframe)
123{
124 unsigned long now;
125
126 now = jiffies;
127 if (now - edc->timestart > timeframe) {
128 edc->errorcount = 1;
129 edc->timestart = now;
130 } else if (++edc->errorcount > max_err) {
131 edc->errorcount = 0;
132 edc->timestart = now;
133 return 1;
134 }
135 return 0;
136}
137
138/* Host-Device interface for USB */
139enum {
140 I2400MU_MAX_NOTIFICATION_LEN = 256,
141 I2400MU_BLK_SIZE = 16,
142 I2400MU_PL_SIZE_MAX = 0x3EFF,
143
144 /* Endpoints */
145 I2400MU_EP_BULK_OUT = 0,
146 I2400MU_EP_NOTIFICATION,
147 I2400MU_EP_RESET_COLD,
148 I2400MU_EP_BULK_IN,
149};
150
151
152/**
153 * struct i2400mu - descriptor for a USB connected i2400m
154 *
155 * @i2400m: bus-generic i2400m implementation; has to be first (see
156 * it's documentation in i2400m.h).
157 *
158 * @usb_dev: pointer to our USB device
159 *
160 * @usb_iface: pointer to our USB interface
161 *
162 * @urb_edc: error density counter; used to keep a density-on-time tab
163 * on how many soft (retryable or ignorable) errors we get. If we
164 * go over the threshold, we consider the bus transport is failing
165 * too much and reset.
166 *
167 * @notif_urb: URB for receiving notifications from the device.
168 *
169 * @tx_kthread: thread we use for data TX. We use a thread because in
170 * order to do deep power saving and put the device to sleep, we
171 * need to call usb_autopm_*() [blocking functions].
172 *
173 * @tx_wq: waitqueue for the TX kthread to sleep when there is no data
174 * to be sent; when more data is available, it is woken up by
175 * i2400mu_bus_tx_kick().
176 *
177 * @rx_kthread: thread we use for data RX. We use a thread because in
178 * order to do deep power saving and put the device to sleep, we
179 * need to call usb_autopm_*() [blocking functions].
180 *
181 * @rx_wq: waitqueue for the RX kthread to sleep when there is no data
182 * to receive. When data is available, it is woken up by
183 * usb-notif.c:i2400mu_notification_grok().
184 *
185 * @rx_pending_count: number of rx-data-ready notifications that were
186 * still not handled by the RX kthread.
187 *
188 * @rx_size: current RX buffer size that is being used.
189 *
190 * @rx_size_acc: accumulator of the sizes of the previous read
191 * transactions.
192 *
193 * @rx_size_cnt: number of read transactions accumulated in
194 * @rx_size_acc.
195 *
196 * @do_autopm: disable(0)/enable(>0) calling the
197 * usb_autopm_get/put_interface() barriers when executing
198 * commands. See doc in i2400mu_suspend() for more information.
199 *
200 * @rx_size_auto_shrink: if true, the rx_size is shrinked
201 * automatically based on the average size of the received
202 * transactions. This allows the receive code to allocate smaller
203 * chunks of memory and thus reduce pressure on the memory
204 * allocator by not wasting so much space. By default it is
205 * enabled.
206 *
207 * @debugfs_dentry: hookup for debugfs files.
208 * These have to be in a separate directory, a child of
209 * (wimax_dev->debugfs_dentry) so they can be removed when the
210 * module unloads, as we don't keep each dentry.
211 */
212struct i2400mu {
213 struct i2400m i2400m; /* FIRST! See doc */
214
215 struct usb_device *usb_dev;
216 struct usb_interface *usb_iface;
217 struct edc urb_edc; /* Error density counter */
218
219 struct urb *notif_urb;
220 struct task_struct *tx_kthread;
221 wait_queue_head_t tx_wq;
222
223 struct task_struct *rx_kthread;
224 wait_queue_head_t rx_wq;
225 atomic_t rx_pending_count;
226 size_t rx_size, rx_size_acc, rx_size_cnt;
227 atomic_t do_autopm;
228 u8 rx_size_auto_shrink;
229
230 struct dentry *debugfs_dentry;
231};
232
233
234static inline
235void i2400mu_init(struct i2400mu *i2400mu)
236{
237 i2400m_init(&i2400mu->i2400m);
238 edc_init(&i2400mu->urb_edc);
239 init_waitqueue_head(&i2400mu->tx_wq);
240 atomic_set(&i2400mu->rx_pending_count, 0);
241 init_waitqueue_head(&i2400mu->rx_wq);
242 i2400mu->rx_size = PAGE_SIZE - sizeof(struct skb_shared_info);
243 atomic_set(&i2400mu->do_autopm, 1);
244 i2400mu->rx_size_auto_shrink = 1;
245}
246
247extern int i2400mu_notification_setup(struct i2400mu *);
248extern void i2400mu_notification_release(struct i2400mu *);
249
250extern int i2400mu_rx_setup(struct i2400mu *);
251extern void i2400mu_rx_release(struct i2400mu *);
252extern void i2400mu_rx_kick(struct i2400mu *);
253
254extern int i2400mu_tx_setup(struct i2400mu *);
255extern void i2400mu_tx_release(struct i2400mu *);
256extern void i2400mu_bus_tx_kick(struct i2400m *);
257
258extern ssize_t i2400mu_bus_bm_cmd_send(struct i2400m *,
259 const struct i2400m_bootrom_header *,
260 size_t, int);
261extern ssize_t i2400mu_bus_bm_wait_for_ack(struct i2400m *,
262 struct i2400m_bootrom_header *,
263 size_t);
264#endif /* #ifndef __I2400M_USB_H__ */