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MIPS: Yosemite, Emma: Fix off-by-two in arcs_cmdline buffer size check
[linux-2.6/linux-mips.git] / drivers / i2c / busses / i2c-xiic.c
blob4bb68f35caf2efc30fdd0466a114ad0822e27d5a
1 /*
2 * i2c-xiic.c
3 * Copyright (c) 2002-2007 Xilinx Inc.
4 * Copyright (c) 2009-2010 Intel Corporation
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 *
19 *
20 * This code was implemented by Mocean Laboratories AB when porting linux
21 * to the automotive development board Russellville. The copyright holder
22 * as seen in the header is Intel corporation.
23 * Mocean Laboratories forked off the GNU/Linux platform work into a
24 * separate company called Pelagicore AB, which committed the code to the
25 * kernel.
26 */
27
28 /* Supports:
29 * Xilinx IIC
30 */
31 #include <linux/kernel.h>
32 #include <linux/module.h>
33 #include <linux/init.h>
34 #include <linux/errno.h>
35 #include <linux/delay.h>
36 #include <linux/platform_device.h>
37 #include <linux/i2c.h>
38 #include <linux/interrupt.h>
39 #include <linux/wait.h>
40 #include <linux/i2c-xiic.h>
41 #include <linux/io.h>
42 #include <linux/slab.h>
43
44 #define DRIVER_NAME "xiic-i2c"
45
46 enum xilinx_i2c_state {
47 STATE_DONE,
48 STATE_ERROR,
49 STATE_START
50 };
51
52 /**
53 * struct xiic_i2c - Internal representation of the XIIC I2C bus
54 * @base: Memory base of the HW registers
55 * @wait: Wait queue for callers
56 * @adap: Kernel adapter representation
57 * @tx_msg: Messages from above to be sent
58 * @lock: Mutual exclusion
59 * @tx_pos: Current pos in TX message
60 * @nmsgs: Number of messages in tx_msg
61 * @state: See STATE_
62 * @rx_msg: Current RX message
63 * @rx_pos: Position within current RX message
64 */
65 struct xiic_i2c {
66 void __iomem *base;
67 wait_queue_head_t wait;
68 struct i2c_adapter adap;
69 struct i2c_msg *tx_msg;
70 spinlock_t lock;
71 unsigned int tx_pos;
72 unsigned int nmsgs;
73 enum xilinx_i2c_state state;
74 struct i2c_msg *rx_msg;
75 int rx_pos;
76 };
77
78
79 #define XIIC_MSB_OFFSET 0
80 #define XIIC_REG_OFFSET (0x100+XIIC_MSB_OFFSET)
81
82 /*
83 * Register offsets in bytes from RegisterBase. Three is added to the
84 * base offset to access LSB (IBM style) of the word
85 */
86 #define XIIC_CR_REG_OFFSET (0x00+XIIC_REG_OFFSET) /* Control Register */
87 #define XIIC_SR_REG_OFFSET (0x04+XIIC_REG_OFFSET) /* Status Register */
88 #define XIIC_DTR_REG_OFFSET (0x08+XIIC_REG_OFFSET) /* Data Tx Register */
89 #define XIIC_DRR_REG_OFFSET (0x0C+XIIC_REG_OFFSET) /* Data Rx Register */
90 #define XIIC_ADR_REG_OFFSET (0x10+XIIC_REG_OFFSET) /* Address Register */
91 #define XIIC_TFO_REG_OFFSET (0x14+XIIC_REG_OFFSET) /* Tx FIFO Occupancy */
92 #define XIIC_RFO_REG_OFFSET (0x18+XIIC_REG_OFFSET) /* Rx FIFO Occupancy */
93 #define XIIC_TBA_REG_OFFSET (0x1C+XIIC_REG_OFFSET) /* 10 Bit Address reg */
94 #define XIIC_RFD_REG_OFFSET (0x20+XIIC_REG_OFFSET) /* Rx FIFO Depth reg */
95 #define XIIC_GPO_REG_OFFSET (0x24+XIIC_REG_OFFSET) /* Output Register */
96
97 /* Control Register masks */
98 #define XIIC_CR_ENABLE_DEVICE_MASK 0x01 /* Device enable = 1 */
99 #define XIIC_CR_TX_FIFO_RESET_MASK 0x02 /* Transmit FIFO reset=1 */
100 #define XIIC_CR_MSMS_MASK 0x04 /* Master starts Txing=1 */
101 #define XIIC_CR_DIR_IS_TX_MASK 0x08 /* Dir of tx. Txing=1 */
102 #define XIIC_CR_NO_ACK_MASK 0x10 /* Tx Ack. NO ack = 1 */
103 #define XIIC_CR_REPEATED_START_MASK 0x20 /* Repeated start = 1 */
104 #define XIIC_CR_GENERAL_CALL_MASK 0x40 /* Gen Call enabled = 1 */
105
106 /* Status Register masks */
107 #define XIIC_SR_GEN_CALL_MASK 0x01 /* 1=a mstr issued a GC */
108 #define XIIC_SR_ADDR_AS_SLAVE_MASK 0x02 /* 1=when addr as slave */
109 #define XIIC_SR_BUS_BUSY_MASK 0x04 /* 1 = bus is busy */
110 #define XIIC_SR_MSTR_RDING_SLAVE_MASK 0x08 /* 1=Dir: mstr <-- slave */
111 #define XIIC_SR_TX_FIFO_FULL_MASK 0x10 /* 1 = Tx FIFO full */
112 #define XIIC_SR_RX_FIFO_FULL_MASK 0x20 /* 1 = Rx FIFO full */
113 #define XIIC_SR_RX_FIFO_EMPTY_MASK 0x40 /* 1 = Rx FIFO empty */
114 #define XIIC_SR_TX_FIFO_EMPTY_MASK 0x80 /* 1 = Tx FIFO empty */
115
116 /* Interrupt Status Register masks Interrupt occurs when... */
117 #define XIIC_INTR_ARB_LOST_MASK 0x01 /* 1 = arbitration lost */
118 #define XIIC_INTR_TX_ERROR_MASK 0x02 /* 1=Tx error/msg complete */
119 #define XIIC_INTR_TX_EMPTY_MASK 0x04 /* 1 = Tx FIFO/reg empty */
120 #define XIIC_INTR_RX_FULL_MASK 0x08 /* 1=Rx FIFO/reg=OCY level */
121 #define XIIC_INTR_BNB_MASK 0x10 /* 1 = Bus not busy */
122 #define XIIC_INTR_AAS_MASK 0x20 /* 1 = when addr as slave */
123 #define XIIC_INTR_NAAS_MASK 0x40 /* 1 = not addr as slave */
124 #define XIIC_INTR_TX_HALF_MASK 0x80 /* 1 = TX FIFO half empty */
125
126 /* The following constants specify the depth of the FIFOs */
127 #define IIC_RX_FIFO_DEPTH 16 /* Rx fifo capacity */
128 #define IIC_TX_FIFO_DEPTH 16 /* Tx fifo capacity */
129
130 /* The following constants specify groups of interrupts that are typically
131 * enabled or disables at the same time
132 */
133 #define XIIC_TX_INTERRUPTS \
134 (XIIC_INTR_TX_ERROR_MASK | XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK)
135
136 #define XIIC_TX_RX_INTERRUPTS (XIIC_INTR_RX_FULL_MASK | XIIC_TX_INTERRUPTS)
137
138 /* The following constants are used with the following macros to specify the
139 * operation, a read or write operation.
140 */
141 #define XIIC_READ_OPERATION 1
142 #define XIIC_WRITE_OPERATION 0
143
144 /*
145 * Tx Fifo upper bit masks.
146 */
147 #define XIIC_TX_DYN_START_MASK 0x0100 /* 1 = Set dynamic start */
148 #define XIIC_TX_DYN_STOP_MASK 0x0200 /* 1 = Set dynamic stop */
149
150 /*
151 * The following constants define the register offsets for the Interrupt
152 * registers. There are some holes in the memory map for reserved addresses
153 * to allow other registers to be added and still match the memory map of the
154 * interrupt controller registers
155 */
156 #define XIIC_DGIER_OFFSET 0x1C /* Device Global Interrupt Enable Register */
157 #define XIIC_IISR_OFFSET 0x20 /* Interrupt Status Register */
158 #define XIIC_IIER_OFFSET 0x28 /* Interrupt Enable Register */
159 #define XIIC_RESETR_OFFSET 0x40 /* Reset Register */
160
161 #define XIIC_RESET_MASK 0xAUL
162
163 /*
164 * The following constant is used for the device global interrupt enable
165 * register, to enable all interrupts for the device, this is the only bit
166 * in the register
167 */
168 #define XIIC_GINTR_ENABLE_MASK 0x80000000UL
169
170 #define xiic_tx_space(i2c) ((i2c)->tx_msg->len - (i2c)->tx_pos)
171 #define xiic_rx_space(i2c) ((i2c)->rx_msg->len - (i2c)->rx_pos)
172
173 static void xiic_start_xfer(struct xiic_i2c *i2c);
174 static void __xiic_start_xfer(struct xiic_i2c *i2c);
175
176 static inline void xiic_setreg8(struct xiic_i2c *i2c, int reg, u8 value)
177 {
178 iowrite8(value, i2c->base + reg);
179 }
180
181 static inline u8 xiic_getreg8(struct xiic_i2c *i2c, int reg)
182 {
183 return ioread8(i2c->base + reg);
184 }
185
186 static inline void xiic_setreg16(struct xiic_i2c *i2c, int reg, u16 value)
187 {
188 iowrite16(value, i2c->base + reg);
189 }
190
191 static inline void xiic_setreg32(struct xiic_i2c *i2c, int reg, int value)
192 {
193 iowrite32(value, i2c->base + reg);
194 }
195
196 static inline int xiic_getreg32(struct xiic_i2c *i2c, int reg)
197 {
198 return ioread32(i2c->base + reg);
199 }
200
201 static inline void xiic_irq_dis(struct xiic_i2c *i2c, u32 mask)
202 {
203 u32 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET);
204 xiic_setreg32(i2c, XIIC_IIER_OFFSET, ier & ~mask);
205 }
206
207 static inline void xiic_irq_en(struct xiic_i2c *i2c, u32 mask)
208 {
209 u32 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET);
210 xiic_setreg32(i2c, XIIC_IIER_OFFSET, ier | mask);
211 }
212
213 static inline void xiic_irq_clr(struct xiic_i2c *i2c, u32 mask)
214 {
215 u32 isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET);
216 xiic_setreg32(i2c, XIIC_IISR_OFFSET, isr & mask);
217 }
218
219 static inline void xiic_irq_clr_en(struct xiic_i2c *i2c, u32 mask)
220 {
221 xiic_irq_clr(i2c, mask);
222 xiic_irq_en(i2c, mask);
223 }
224
225 static void xiic_clear_rx_fifo(struct xiic_i2c *i2c)
226 {
227 u8 sr;
228 for (sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET);
229 !(sr & XIIC_SR_RX_FIFO_EMPTY_MASK);
230 sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET))
231 xiic_getreg8(i2c, XIIC_DRR_REG_OFFSET);
232 }
233
234 static void xiic_reinit(struct xiic_i2c *i2c)
235 {
236 xiic_setreg32(i2c, XIIC_RESETR_OFFSET, XIIC_RESET_MASK);
237
238 /* Set receive Fifo depth to maximum (zero based). */
239 xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, IIC_RX_FIFO_DEPTH - 1);
240
241 /* Reset Tx Fifo. */
242 xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_TX_FIFO_RESET_MASK);
243
244 /* Enable IIC Device, remove Tx Fifo reset & disable general call. */
245 xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_ENABLE_DEVICE_MASK);
246
247 /* make sure RX fifo is empty */
248 xiic_clear_rx_fifo(i2c);
249
250 /* Enable interrupts */
251 xiic_setreg32(i2c, XIIC_DGIER_OFFSET, XIIC_GINTR_ENABLE_MASK);
252
253 xiic_irq_clr_en(i2c, XIIC_INTR_AAS_MASK | XIIC_INTR_ARB_LOST_MASK);
254 }
255
256 static void xiic_deinit(struct xiic_i2c *i2c)
257 {
258 u8 cr;
259
260 xiic_setreg32(i2c, XIIC_RESETR_OFFSET, XIIC_RESET_MASK);
261
262 /* Disable IIC Device. */
263 cr = xiic_getreg8(i2c, XIIC_CR_REG_OFFSET);
264 xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, cr & ~XIIC_CR_ENABLE_DEVICE_MASK);
265 }
266
267 static void xiic_read_rx(struct xiic_i2c *i2c)
268 {
269 u8 bytes_in_fifo;
270 int i;
271
272 bytes_in_fifo = xiic_getreg8(i2c, XIIC_RFO_REG_OFFSET) + 1;
273
274 dev_dbg(i2c->adap.dev.parent, "%s entry, bytes in fifo: %d, msg: %d"
275 ", SR: 0x%x, CR: 0x%x\n",
276 __func__, bytes_in_fifo, xiic_rx_space(i2c),
277 xiic_getreg8(i2c, XIIC_SR_REG_OFFSET),
278 xiic_getreg8(i2c, XIIC_CR_REG_OFFSET));
279
280 if (bytes_in_fifo > xiic_rx_space(i2c))
281 bytes_in_fifo = xiic_rx_space(i2c);
282
283 for (i = 0; i < bytes_in_fifo; i++)
284 i2c->rx_msg->buf[i2c->rx_pos++] =
285 xiic_getreg8(i2c, XIIC_DRR_REG_OFFSET);
286
287 xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET,
288 (xiic_rx_space(i2c) > IIC_RX_FIFO_DEPTH) ?
289 IIC_RX_FIFO_DEPTH - 1 : xiic_rx_space(i2c) - 1);
290 }
291
292 static int xiic_tx_fifo_space(struct xiic_i2c *i2c)
293 {
294 /* return the actual space left in the FIFO */
295 return IIC_TX_FIFO_DEPTH - xiic_getreg8(i2c, XIIC_TFO_REG_OFFSET) - 1;
296 }
297
298 static void xiic_fill_tx_fifo(struct xiic_i2c *i2c)
299 {
300 u8 fifo_space = xiic_tx_fifo_space(i2c);
301 int len = xiic_tx_space(i2c);
302
303 len = (len > fifo_space) ? fifo_space : len;
304
305 dev_dbg(i2c->adap.dev.parent, "%s entry, len: %d, fifo space: %d\n",
306 __func__, len, fifo_space);
307
308 while (len--) {
309 u16 data = i2c->tx_msg->buf[i2c->tx_pos++];
310 if ((xiic_tx_space(i2c) == 0) && (i2c->nmsgs == 1)) {
311 /* last message in transfer -> STOP */
312 data |= XIIC_TX_DYN_STOP_MASK;
313 dev_dbg(i2c->adap.dev.parent, "%s TX STOP\n", __func__);
314
315 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data);
316 } else
317 xiic_setreg8(i2c, XIIC_DTR_REG_OFFSET, data);
318 }
319 }
320
321 static void xiic_wakeup(struct xiic_i2c *i2c, int code)
322 {
323 i2c->tx_msg = NULL;
324 i2c->rx_msg = NULL;
325 i2c->nmsgs = 0;
326 i2c->state = code;
327 wake_up(&i2c->wait);
328 }
329
330 static void xiic_process(struct xiic_i2c *i2c)
331 {
332 u32 pend, isr, ier;
333 u32 clr = 0;
334
335 /* Get the interrupt Status from the IPIF. There is no clearing of
336 * interrupts in the IPIF. Interrupts must be cleared at the source.
337 * To find which interrupts are pending; AND interrupts pending with
338 * interrupts masked.
339 */
340 isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET);
341 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET);
342 pend = isr & ier;
343
344 dev_dbg(i2c->adap.dev.parent, "%s entry, IER: 0x%x, ISR: 0x%x, "
345 "pend: 0x%x, SR: 0x%x, msg: %p, nmsgs: %d\n",
346 __func__, ier, isr, pend, xiic_getreg8(i2c, XIIC_SR_REG_OFFSET),
347 i2c->tx_msg, i2c->nmsgs);
348
349 /* Do not processes a devices interrupts if the device has no
350 * interrupts pending
351 */
352 if (!pend)
353 return;
354
355 /* Service requesting interrupt */
356 if ((pend & XIIC_INTR_ARB_LOST_MASK) ||
357 ((pend & XIIC_INTR_TX_ERROR_MASK) &&
358 !(pend & XIIC_INTR_RX_FULL_MASK))) {
359 /* bus arbritration lost, or...
360 * Transmit error _OR_ RX completed
361 * if this happens when RX_FULL is not set
362 * this is probably a TX error
363 */
364
365 dev_dbg(i2c->adap.dev.parent, "%s error\n", __func__);
366
367 /* dynamic mode seem to suffer from problems if we just flushes
368 * fifos and the next message is a TX with len 0 (only addr)
369 * reset the IP instead of just flush fifos
370 */
371 xiic_reinit(i2c);
372
373 if (i2c->tx_msg)
374 xiic_wakeup(i2c, STATE_ERROR);
375
376 } else if (pend & XIIC_INTR_RX_FULL_MASK) {
377 /* Receive register/FIFO is full */
378
379 clr = XIIC_INTR_RX_FULL_MASK;
380 if (!i2c->rx_msg) {
381 dev_dbg(i2c->adap.dev.parent,
382 "%s unexpexted RX IRQ\n", __func__);
383 xiic_clear_rx_fifo(i2c);
384 goto out;
385 }
386
387 xiic_read_rx(i2c);
388 if (xiic_rx_space(i2c) == 0) {
389 /* this is the last part of the message */
390 i2c->rx_msg = NULL;
391
392 /* also clear TX error if there (RX complete) */
393 clr |= (isr & XIIC_INTR_TX_ERROR_MASK);
394
395 dev_dbg(i2c->adap.dev.parent,
396 "%s end of message, nmsgs: %d\n",
397 __func__, i2c->nmsgs);
398
399 /* send next message if this wasn't the last,
400 * otherwise the transfer will be finialise when
401 * receiving the bus not busy interrupt
402 */
403 if (i2c->nmsgs > 1) {
404 i2c->nmsgs--;
405 i2c->tx_msg++;
406 dev_dbg(i2c->adap.dev.parent,
407 "%s will start next...\n", __func__);
408
409 __xiic_start_xfer(i2c);
410 }
411 }
412 } else if (pend & XIIC_INTR_BNB_MASK) {
413 /* IIC bus has transitioned to not busy */
414 clr = XIIC_INTR_BNB_MASK;
415
416 /* The bus is not busy, disable BusNotBusy interrupt */
417 xiic_irq_dis(i2c, XIIC_INTR_BNB_MASK);
418
419 if (!i2c->tx_msg)
420 goto out;
421
422 if ((i2c->nmsgs == 1) && !i2c->rx_msg &&
423 xiic_tx_space(i2c) == 0)
424 xiic_wakeup(i2c, STATE_DONE);
425 else
426 xiic_wakeup(i2c, STATE_ERROR);
427
428 } else if (pend & (XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK)) {
429 /* Transmit register/FIFO is empty or ½ empty */
430
431 clr = pend &
432 (XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK);
433
434 if (!i2c->tx_msg) {
435 dev_dbg(i2c->adap.dev.parent,
436 "%s unexpexted TX IRQ\n", __func__);
437 goto out;
438 }
439
440 xiic_fill_tx_fifo(i2c);
441
442 /* current message sent and there is space in the fifo */
443 if (!xiic_tx_space(i2c) && xiic_tx_fifo_space(i2c) >= 2) {
444 dev_dbg(i2c->adap.dev.parent,
445 "%s end of message sent, nmsgs: %d\n",
446 __func__, i2c->nmsgs);
447 if (i2c->nmsgs > 1) {
448 i2c->nmsgs--;
449 i2c->tx_msg++;
450 __xiic_start_xfer(i2c);
451 } else {
452 xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK);
453
454 dev_dbg(i2c->adap.dev.parent,
455 "%s Got TX IRQ but no more to do...\n",
456 __func__);
457 }
458 } else if (!xiic_tx_space(i2c) && (i2c->nmsgs == 1))
459 /* current frame is sent and is last,
460 * make sure to disable tx half
461 */
462 xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK);
463 } else {
464 /* got IRQ which is not acked */
465 dev_err(i2c->adap.dev.parent, "%s Got unexpected IRQ\n",
466 __func__);
467 clr = pend;
468 }
469 out:
470 dev_dbg(i2c->adap.dev.parent, "%s clr: 0x%x\n", __func__, clr);
471
472 xiic_setreg32(i2c, XIIC_IISR_OFFSET, clr);
473 }
474
475 static int xiic_bus_busy(struct xiic_i2c *i2c)
476 {
477 u8 sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET);
478
479 return (sr & XIIC_SR_BUS_BUSY_MASK) ? -EBUSY : 0;
480 }
481
482 static int xiic_busy(struct xiic_i2c *i2c)
483 {
484 int tries = 3;
485 int err;
486
487 if (i2c->tx_msg)
488 return -EBUSY;
489
490 /* for instance if previous transfer was terminated due to TX error
491 * it might be that the bus is on it's way to become available
492 * give it at most 3 ms to wake
493 */
494 err = xiic_bus_busy(i2c);
495 while (err && tries--) {
496 mdelay(1);
497 err = xiic_bus_busy(i2c);
498 }
499
500 return err;
501 }
502
503 static void xiic_start_recv(struct xiic_i2c *i2c)
504 {
505 u8 rx_watermark;
506 struct i2c_msg *msg = i2c->rx_msg = i2c->tx_msg;
507
508 /* Clear and enable Rx full interrupt. */
509 xiic_irq_clr_en(i2c, XIIC_INTR_RX_FULL_MASK | XIIC_INTR_TX_ERROR_MASK);
510
511 /* we want to get all but last byte, because the TX_ERROR IRQ is used
512 * to inidicate error ACK on the address, and negative ack on the last
513 * received byte, so to not mix them receive all but last.
514 * In the case where there is only one byte to receive
515 * we can check if ERROR and RX full is set at the same time
516 */
517 rx_watermark = msg->len;
518 if (rx_watermark > IIC_RX_FIFO_DEPTH)
519 rx_watermark = IIC_RX_FIFO_DEPTH;
520 xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, rx_watermark - 1);
521
522 if (!(msg->flags & I2C_M_NOSTART))
523 /* write the address */
524 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET,
525 (msg->addr << 1) | XIIC_READ_OPERATION |
526 XIIC_TX_DYN_START_MASK);
527
528 xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK);
529
530 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET,
531 msg->len | ((i2c->nmsgs == 1) ? XIIC_TX_DYN_STOP_MASK : 0));
532 if (i2c->nmsgs == 1)
533 /* very last, enable bus not busy as well */
534 xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK);
535
536 /* the message is tx:ed */
537 i2c->tx_pos = msg->len;
538 }
539
540 static void xiic_start_send(struct xiic_i2c *i2c)
541 {
542 struct i2c_msg *msg = i2c->tx_msg;
543
544 xiic_irq_clr(i2c, XIIC_INTR_TX_ERROR_MASK);
545
546 dev_dbg(i2c->adap.dev.parent, "%s entry, msg: %p, len: %d, "
547 "ISR: 0x%x, CR: 0x%x\n",
548 __func__, msg, msg->len, xiic_getreg32(i2c, XIIC_IISR_OFFSET),
549 xiic_getreg8(i2c, XIIC_CR_REG_OFFSET));
550
551 if (!(msg->flags & I2C_M_NOSTART)) {
552 /* write the address */
553 u16 data = ((msg->addr << 1) & 0xfe) | XIIC_WRITE_OPERATION |
554 XIIC_TX_DYN_START_MASK;
555 if ((i2c->nmsgs == 1) && msg->len == 0)
556 /* no data and last message -> add STOP */
557 data |= XIIC_TX_DYN_STOP_MASK;
558
559 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data);
560 }
561
562 xiic_fill_tx_fifo(i2c);
563
564 /* Clear any pending Tx empty, Tx Error and then enable them. */
565 xiic_irq_clr_en(i2c, XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_ERROR_MASK |
566 XIIC_INTR_BNB_MASK);
567 }
568
569 static irqreturn_t xiic_isr(int irq, void *dev_id)
570 {
571 struct xiic_i2c *i2c = dev_id;
572
573 spin_lock(&i2c->lock);
574 /* disable interrupts globally */
575 xiic_setreg32(i2c, XIIC_DGIER_OFFSET, 0);
576
577 dev_dbg(i2c->adap.dev.parent, "%s entry\n", __func__);
578
579 xiic_process(i2c);
580
581 xiic_setreg32(i2c, XIIC_DGIER_OFFSET, XIIC_GINTR_ENABLE_MASK);
582 spin_unlock(&i2c->lock);
583
584 return IRQ_HANDLED;
585 }
586
587 static void __xiic_start_xfer(struct xiic_i2c *i2c)
588 {
589 int first = 1;
590 int fifo_space = xiic_tx_fifo_space(i2c);
591 dev_dbg(i2c->adap.dev.parent, "%s entry, msg: %p, fifos space: %d\n",
592 __func__, i2c->tx_msg, fifo_space);
593
594 if (!i2c->tx_msg)
595 return;
596
597 i2c->rx_pos = 0;
598 i2c->tx_pos = 0;
599 i2c->state = STATE_START;
600 while ((fifo_space >= 2) && (first || (i2c->nmsgs > 1))) {
601 if (!first) {
602 i2c->nmsgs--;
603 i2c->tx_msg++;
604 i2c->tx_pos = 0;
605 } else
606 first = 0;
607
608 if (i2c->tx_msg->flags & I2C_M_RD) {
609 /* we dont date putting several reads in the FIFO */
610 xiic_start_recv(i2c);
611 return;
612 } else {
613 xiic_start_send(i2c);
614 if (xiic_tx_space(i2c) != 0) {
615 /* the message could not be completely sent */
616 break;
617 }
618 }
619
620 fifo_space = xiic_tx_fifo_space(i2c);
621 }
622
623 /* there are more messages or the current one could not be completely
624 * put into the FIFO, also enable the half empty interrupt
625 */
626 if (i2c->nmsgs > 1 || xiic_tx_space(i2c))
627 xiic_irq_clr_en(i2c, XIIC_INTR_TX_HALF_MASK);
628
629 }
630
631 static void xiic_start_xfer(struct xiic_i2c *i2c)
632 {
633 unsigned long flags;
634
635 spin_lock_irqsave(&i2c->lock, flags);
636 xiic_reinit(i2c);
637 /* disable interrupts globally */
638 xiic_setreg32(i2c, XIIC_DGIER_OFFSET, 0);
639 spin_unlock_irqrestore(&i2c->lock, flags);
640
641 __xiic_start_xfer(i2c);
642 xiic_setreg32(i2c, XIIC_DGIER_OFFSET, XIIC_GINTR_ENABLE_MASK);
643 }
644
645 static int xiic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
646 {
647 struct xiic_i2c *i2c = i2c_get_adapdata(adap);
648 int err;
649
650 dev_dbg(adap->dev.parent, "%s entry SR: 0x%x\n", __func__,
651 xiic_getreg8(i2c, XIIC_SR_REG_OFFSET));
652
653 err = xiic_busy(i2c);
654 if (err)
655 return err;
656
657 i2c->tx_msg = msgs;
658 i2c->nmsgs = num;
659
660 xiic_start_xfer(i2c);
661
662 if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) ||
663 (i2c->state == STATE_DONE), HZ))
664 return (i2c->state == STATE_DONE) ? num : -EIO;
665 else {
666 i2c->tx_msg = NULL;
667 i2c->rx_msg = NULL;
668 i2c->nmsgs = 0;
669 return -ETIMEDOUT;
670 }
671 }
672
673 static u32 xiic_func(struct i2c_adapter *adap)
674 {
675 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
676 }
677
678 static const struct i2c_algorithm xiic_algorithm = {
679 .master_xfer = xiic_xfer,
680 .functionality = xiic_func,
681 };
682
683 static struct i2c_adapter xiic_adapter = {
684 .owner = THIS_MODULE,
685 .name = DRIVER_NAME,
686 .class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
687 .algo = &xiic_algorithm,
688 };
689
690
691 static int __devinit xiic_i2c_probe(struct platform_device *pdev)
692 {
693 struct xiic_i2c *i2c;
694 struct xiic_i2c_platform_data *pdata;
695 struct resource *res;
696 int ret, irq;
697 u8 i;
698
699 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
700 if (!res)
701 goto resource_missing;
702
703 irq = platform_get_irq(pdev, 0);
704 if (irq < 0)
705 goto resource_missing;
706
707 pdata = (struct xiic_i2c_platform_data *) pdev->dev.platform_data;
708 if (!pdata)
709 return -EINVAL;
710
711 i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);
712 if (!i2c)
713 return -ENOMEM;
714
715 if (!request_mem_region(res->start, resource_size(res), pdev->name)) {
716 dev_err(&pdev->dev, "Memory region busy\n");
717 ret = -EBUSY;
718 goto request_mem_failed;
719 }
720
721 i2c->base = ioremap(res->start, resource_size(res));
722 if (!i2c->base) {
723 dev_err(&pdev->dev, "Unable to map registers\n");
724 ret = -EIO;
725 goto map_failed;
726 }
727
728 /* hook up driver to tree */
729 platform_set_drvdata(pdev, i2c);
730 i2c->adap = xiic_adapter;
731 i2c_set_adapdata(&i2c->adap, i2c);
732 i2c->adap.dev.parent = &pdev->dev;
733
734 xiic_reinit(i2c);
735
736 spin_lock_init(&i2c->lock);
737 init_waitqueue_head(&i2c->wait);
738 ret = request_irq(irq, xiic_isr, 0, pdev->name, i2c);
739 if (ret) {
740 dev_err(&pdev->dev, "Cannot claim IRQ\n");
741 goto request_irq_failed;
742 }
743
744 /* add i2c adapter to i2c tree */
745 ret = i2c_add_adapter(&i2c->adap);
746 if (ret) {
747 dev_err(&pdev->dev, "Failed to add adapter\n");
748 goto add_adapter_failed;
749 }
750
751 /* add in known devices to the bus */
752 for (i = 0; i < pdata->num_devices; i++)
753 i2c_new_device(&i2c->adap, pdata->devices + i);
754
755 return 0;
756
757 add_adapter_failed:
758 free_irq(irq, i2c);
759 request_irq_failed:
760 xiic_deinit(i2c);
761 iounmap(i2c->base);
762 map_failed:
763 release_mem_region(res->start, resource_size(res));
764 request_mem_failed:
765 kfree(i2c);
766
767 return ret;
768 resource_missing:
769 dev_err(&pdev->dev, "IRQ or Memory resource is missing\n");
770 return -ENOENT;
771 }
772
773 static int __devexit xiic_i2c_remove(struct platform_device* pdev)
774 {
775 struct xiic_i2c *i2c = platform_get_drvdata(pdev);
776 struct resource *res;
777
778 /* remove adapter & data */
779 i2c_del_adapter(&i2c->adap);
780
781 xiic_deinit(i2c);
782
783 platform_set_drvdata(pdev, NULL);
784
785 free_irq(platform_get_irq(pdev, 0), i2c);
786
787 iounmap(i2c->base);
788
789 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
790 if (res)
791 release_mem_region(res->start, resource_size(res));
792
793 kfree(i2c);
794
795 return 0;
796 }
797
798
799 /* work with hotplug and coldplug */
800 MODULE_ALIAS("platform:"DRIVER_NAME);
801
802 static struct platform_driver xiic_i2c_driver = {
803 .probe = xiic_i2c_probe,
804 .remove = __devexit_p(xiic_i2c_remove),
805 .driver = {
806 .owner = THIS_MODULE,
807 .name = DRIVER_NAME,
808 },
809 };
810
811 static int __init xiic_i2c_init(void)
812 {
813 return platform_driver_register(&xiic_i2c_driver);
814 }
815
816 static void __exit xiic_i2c_exit(void)
817 {
818 platform_driver_unregister(&xiic_i2c_driver);
819 }
820
821 module_init(xiic_i2c_init);
822 module_exit(xiic_i2c_exit);
823
824 MODULE_AUTHOR("info@mocean-labs.com");
825 MODULE_DESCRIPTION("Xilinx I2C bus driver");
826 MODULE_LICENSE("GPL v2");
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