2 * LocalPlus Bus FIFO driver for the Freescale MPC52xx.
4 * Copyright (C) 2009 Secret Lab Technologies Ltd.
6 * This file is released under the GPLv2
9 * - Add support for multiple requests to be queued.
12 #include <linux/interrupt.h>
13 #include <linux/kernel.h>
15 #include <linux/of_platform.h>
16 #include <linux/spinlock.h>
17 #include <linux/module.h>
20 #include <asm/mpc52xx.h>
23 #include <sysdev/bestcomm/bestcomm.h>
24 #include <sysdev/bestcomm/bestcomm_priv.h>
25 #include <sysdev/bestcomm/gen_bd.h>
27 MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
28 MODULE_DESCRIPTION("MPC5200 LocalPlus FIFO device driver");
29 MODULE_LICENSE("GPL");
31 #define LPBFIFO_REG_PACKET_SIZE (0x00)
32 #define LPBFIFO_REG_START_ADDRESS (0x04)
33 #define LPBFIFO_REG_CONTROL (0x08)
34 #define LPBFIFO_REG_ENABLE (0x0C)
35 #define LPBFIFO_REG_BYTES_DONE_STATUS (0x14)
36 #define LPBFIFO_REG_FIFO_DATA (0x40)
37 #define LPBFIFO_REG_FIFO_STATUS (0x44)
38 #define LPBFIFO_REG_FIFO_CONTROL (0x48)
39 #define LPBFIFO_REG_FIFO_ALARM (0x4C)
41 struct mpc52xx_lpbfifo
{
43 phys_addr_t regs_phys
;
48 struct bcom_task
*bcom_tx_task
;
49 struct bcom_task
*bcom_rx_task
;
50 struct bcom_task
*bcom_cur_task
;
52 /* Current state data */
53 struct mpc52xx_lpbfifo_request
*req
;
57 /* The MPC5200 has only one fifo, so only need one instance structure */
58 static struct mpc52xx_lpbfifo lpbfifo
;
61 * mpc52xx_lpbfifo_kick - Trigger the next block of data to be transferred
63 static void mpc52xx_lpbfifo_kick(struct mpc52xx_lpbfifo_request
*req
)
65 size_t transfer_size
= req
->size
- req
->pos
;
71 int dma
= !(req
->flags
& MPC52XX_LPBFIFO_FLAG_NO_DMA
);
72 int write
= req
->flags
& MPC52XX_LPBFIFO_FLAG_WRITE
;
73 int poll_dma
= req
->flags
& MPC52XX_LPBFIFO_FLAG_POLL_DMA
;
75 /* Set and clear the reset bits; is good practice in User Manual */
76 out_be32(lpbfifo
.regs
+ LPBFIFO_REG_ENABLE
, 0x01010000);
78 /* set master enable bit */
79 out_be32(lpbfifo
.regs
+ LPBFIFO_REG_ENABLE
, 0x00000001);
81 /* While the FIFO can be setup for transfer sizes as large as
82 * 16M-1, the FIFO itself is only 512 bytes deep and it does
83 * not generate interrupts for FIFO full events (only transfer
84 * complete will raise an IRQ). Therefore when not using
85 * Bestcomm to drive the FIFO it needs to either be polled, or
86 * transfers need to constrained to the size of the fifo.
88 * This driver restricts the size of the transfer
90 if (transfer_size
> 512)
93 /* Load the FIFO with data */
95 reg
= lpbfifo
.regs
+ LPBFIFO_REG_FIFO_DATA
;
96 data
= req
->data
+ req
->pos
;
97 for (i
= 0; i
< transfer_size
; i
+= 4)
98 out_be32(reg
, *data
++);
101 /* Unmask both error and completion irqs */
102 out_be32(lpbfifo
.regs
+ LPBFIFO_REG_ENABLE
, 0x00000301);
104 /* Choose the correct direction
106 * Configure the watermarks so DMA will always complete correctly.
107 * It may be worth experimenting with the ALARM value to see if
108 * there is a performance impacit. However, if it is wrong there
109 * is a risk of DMA not transferring the last chunk of data
112 out_be32(lpbfifo
.regs
+ LPBFIFO_REG_FIFO_ALARM
, 0x1e4);
113 out_8(lpbfifo
.regs
+ LPBFIFO_REG_FIFO_CONTROL
, 7);
114 lpbfifo
.bcom_cur_task
= lpbfifo
.bcom_tx_task
;
116 out_be32(lpbfifo
.regs
+ LPBFIFO_REG_FIFO_ALARM
, 0x1ff);
117 out_8(lpbfifo
.regs
+ LPBFIFO_REG_FIFO_CONTROL
, 0);
118 lpbfifo
.bcom_cur_task
= lpbfifo
.bcom_rx_task
;
121 if (lpbfifo
.dma_irqs_enabled
) {
122 disable_irq(bcom_get_task_irq(lpbfifo
.bcom_rx_task
));
123 lpbfifo
.dma_irqs_enabled
= 0;
126 if (!lpbfifo
.dma_irqs_enabled
) {
127 enable_irq(bcom_get_task_irq(lpbfifo
.bcom_rx_task
));
128 lpbfifo
.dma_irqs_enabled
= 1;
133 bd
= bcom_prepare_next_buffer(lpbfifo
.bcom_cur_task
);
134 bd
->status
= transfer_size
;
137 * In the DMA read case, the DMA doesn't complete,
138 * possibly due to incorrect watermarks in the ALARM
139 * and CONTROL regs. For now instead of trying to
140 * determine the right watermarks that will make this
141 * work, just increase the number of bytes the FIFO is
144 * When submitting another operation, the FIFO will get
145 * reset, so the condition of the FIFO waiting for a
146 * non-existent 4 bytes will get cleared.
148 transfer_size
+= 4; /* BLECH! */
150 bd
->data
[0] = req
->data_phys
+ req
->pos
;
151 bcom_submit_next_buffer(lpbfifo
.bcom_cur_task
, NULL
);
153 /* error irq & master enabled bit */
154 bit_fields
= 0x00000201;
157 if (write
&& (!poll_dma
))
158 bit_fields
|= 0x00000100; /* completion irq too */
159 out_be32(lpbfifo
.regs
+ LPBFIFO_REG_ENABLE
, bit_fields
);
162 /* Set transfer size, width, chip select and READ mode */
163 out_be32(lpbfifo
.regs
+ LPBFIFO_REG_START_ADDRESS
,
164 req
->offset
+ req
->pos
);
165 out_be32(lpbfifo
.regs
+ LPBFIFO_REG_PACKET_SIZE
, transfer_size
);
167 bit_fields
= req
->cs
<< 24 | 0x000008;
169 bit_fields
|= 0x010000; /* read mode */
170 out_be32(lpbfifo
.regs
+ LPBFIFO_REG_CONTROL
, bit_fields
);
173 if (!lpbfifo
.req
->defer_xfer_start
)
174 out_8(lpbfifo
.regs
+ LPBFIFO_REG_PACKET_SIZE
, 0x01);
176 bcom_enable(lpbfifo
.bcom_cur_task
);
180 * mpc52xx_lpbfifo_irq - IRQ handler for LPB FIFO
182 * On transmit, the dma completion irq triggers before the fifo completion
183 * triggers. Handle the dma completion here instead of the LPB FIFO Bestcomm
184 * task completion irq because everything is not really done until the LPB FIFO
185 * completion irq triggers.
188 * For DMA, on receive, the "Fat Lady" is the bestcom completion irq. on
189 * transmit, the fifo completion irq is the "Fat Lady". The opera (or in this
190 * case the DMA/FIFO operation) is not finished until the "Fat Lady" sings.
192 * Reasons for entering this routine:
193 * 1) PIO mode rx and tx completion irq
194 * 2) DMA interrupt mode tx completion irq
195 * 3) DMA polled mode tx
198 * 1) Transfer aborted
199 * 2) FIFO complete without DMA; more data to do
200 * 3) FIFO complete without DMA; all data transferred
201 * 4) FIFO complete using DMA
203 * Condition 1 can occur regardless of whether or not DMA is used.
204 * It requires executing the callback to report the error and exiting
207 * Condition 2 requires programming the FIFO with the next block of data
209 * Condition 3 requires executing the callback to report completion
211 * Condition 4 means the same as 3, except that we also retrieve the bcom
212 * buffer so DMA doesn't get clogged up.
214 * To make things trickier, the spinlock must be dropped before
215 * executing the callback, otherwise we could end up with a deadlock
216 * or nested spinlock condition. The out path is non-trivial, so
217 * extra fiddling is done to make sure all paths lead to the same
220 static irqreturn_t
mpc52xx_lpbfifo_irq(int irq
, void *dev_id
)
222 struct mpc52xx_lpbfifo_request
*req
;
223 u32 status
= in_8(lpbfifo
.regs
+ LPBFIFO_REG_BYTES_DONE_STATUS
);
230 int dma
, write
, poll_dma
;
232 spin_lock_irqsave(&lpbfifo
.lock
, flags
);
237 spin_unlock_irqrestore(&lpbfifo
.lock
, flags
);
238 pr_err("bogus LPBFIFO IRQ\n");
242 dma
= !(req
->flags
& MPC52XX_LPBFIFO_FLAG_NO_DMA
);
243 write
= req
->flags
& MPC52XX_LPBFIFO_FLAG_WRITE
;
244 poll_dma
= req
->flags
& MPC52XX_LPBFIFO_FLAG_POLL_DMA
;
247 spin_unlock_irqrestore(&lpbfifo
.lock
, flags
);
248 pr_err("bogus LPBFIFO IRQ (dma and not writting)\n");
252 if ((status
& 0x01) == 0) {
256 /* check abort bit */
258 out_be32(lpbfifo
.regs
+ LPBFIFO_REG_ENABLE
, 0x01010000);
263 /* Read result from hardware */
264 count
= in_be32(lpbfifo
.regs
+ LPBFIFO_REG_BYTES_DONE_STATUS
);
267 if (!dma
&& !write
) {
268 /* copy the data out of the FIFO */
269 reg
= lpbfifo
.regs
+ LPBFIFO_REG_FIFO_DATA
;
270 data
= req
->data
+ req
->pos
;
271 for (i
= 0; i
< count
; i
+= 4)
272 *data
++ = in_be32(reg
);
275 /* Update transfer position and count */
278 /* Decide what to do next */
279 if (req
->size
- req
->pos
)
280 mpc52xx_lpbfifo_kick(req
); /* more work to do */
286 out_8(lpbfifo
.regs
+ LPBFIFO_REG_BYTES_DONE_STATUS
, 0x01);
288 if (dma
&& (status
& 0x11)) {
290 * Count the DMA as complete only when the FIFO completion
291 * status or abort bits are set.
293 * (status & 0x01) should always be the case except sometimes
294 * when using polled DMA.
296 * (status & 0x10) {transfer aborted}: This case needs more
299 bcom_retrieve_buffer(lpbfifo
.bcom_cur_task
, &status
, NULL
);
301 req
->last_byte
= ((u8
*)req
->data
)[req
->size
- 1];
303 /* When the do_callback flag is set; it means the transfer is finished
304 * so set the FIFO as idle */
308 if (irq
!= 0) /* don't increment on polled case */
311 req
->irq_ticks
+= get_tbl() - ts
;
312 spin_unlock_irqrestore(&lpbfifo
.lock
, flags
);
314 /* Spinlock is released; it is now safe to call the callback */
315 if (do_callback
&& req
->callback
)
322 * mpc52xx_lpbfifo_bcom_irq - IRQ handler for LPB FIFO Bestcomm task
324 * Only used when receiving data.
326 static irqreturn_t
mpc52xx_lpbfifo_bcom_irq(int irq
, void *dev_id
)
328 struct mpc52xx_lpbfifo_request
*req
;
333 spin_lock_irqsave(&lpbfifo
.lock
, flags
);
337 if (!req
|| (req
->flags
& MPC52XX_LPBFIFO_FLAG_NO_DMA
)) {
338 spin_unlock_irqrestore(&lpbfifo
.lock
, flags
);
342 if (irq
!= 0) /* don't increment on polled case */
345 if (!bcom_buffer_done(lpbfifo
.bcom_cur_task
)) {
346 spin_unlock_irqrestore(&lpbfifo
.lock
, flags
);
348 req
->buffer_not_done_cnt
++;
349 if ((req
->buffer_not_done_cnt
% 1000) == 0)
350 pr_err("transfer stalled\n");
355 bcom_retrieve_buffer(lpbfifo
.bcom_cur_task
, &status
, NULL
);
357 req
->last_byte
= ((u8
*)req
->data
)[req
->size
- 1];
359 req
->pos
= status
& 0x00ffffff;
361 /* Mark the FIFO as idle */
364 /* Release the lock before calling out to the callback. */
365 req
->irq_ticks
+= get_tbl() - ts
;
366 spin_unlock_irqrestore(&lpbfifo
.lock
, flags
);
375 * mpc52xx_lpbfifo_bcom_poll - Poll for DMA completion
377 void mpc52xx_lpbfifo_poll(void)
379 struct mpc52xx_lpbfifo_request
*req
= lpbfifo
.req
;
380 int dma
= !(req
->flags
& MPC52XX_LPBFIFO_FLAG_NO_DMA
);
381 int write
= req
->flags
& MPC52XX_LPBFIFO_FLAG_WRITE
;
384 * For more information, see comments on the "Fat Lady"
387 mpc52xx_lpbfifo_irq(0, NULL
);
389 mpc52xx_lpbfifo_bcom_irq(0, NULL
);
391 EXPORT_SYMBOL(mpc52xx_lpbfifo_poll
);
394 * mpc52xx_lpbfifo_submit - Submit an LPB FIFO transfer request.
395 * @req: Pointer to request structure
397 int mpc52xx_lpbfifo_submit(struct mpc52xx_lpbfifo_request
*req
)
404 spin_lock_irqsave(&lpbfifo
.lock
, flags
);
406 /* If the req pointer is already set, then a transfer is in progress */
408 spin_unlock_irqrestore(&lpbfifo
.lock
, flags
);
412 /* Setup the transfer */
416 req
->buffer_not_done_cnt
= 0;
419 mpc52xx_lpbfifo_kick(req
);
420 spin_unlock_irqrestore(&lpbfifo
.lock
, flags
);
423 EXPORT_SYMBOL(mpc52xx_lpbfifo_submit
);
425 int mpc52xx_lpbfifo_start_xfer(struct mpc52xx_lpbfifo_request
*req
)
432 spin_lock_irqsave(&lpbfifo
.lock
, flags
);
435 * If the req pointer is already set and a transfer was
436 * started on submit, then this transfer is in progress
438 if (lpbfifo
.req
&& !lpbfifo
.req
->defer_xfer_start
) {
439 spin_unlock_irqrestore(&lpbfifo
.lock
, flags
);
444 * If the req was previously submitted but not
445 * started, start it now
447 if (lpbfifo
.req
&& lpbfifo
.req
== req
&&
448 lpbfifo
.req
->defer_xfer_start
) {
449 out_8(lpbfifo
.regs
+ LPBFIFO_REG_PACKET_SIZE
, 0x01);
452 spin_unlock_irqrestore(&lpbfifo
.lock
, flags
);
455 EXPORT_SYMBOL(mpc52xx_lpbfifo_start_xfer
);
457 void mpc52xx_lpbfifo_abort(struct mpc52xx_lpbfifo_request
*req
)
461 spin_lock_irqsave(&lpbfifo
.lock
, flags
);
462 if (lpbfifo
.req
== req
) {
463 /* Put it into reset and clear the state */
464 bcom_gen_bd_rx_reset(lpbfifo
.bcom_rx_task
);
465 bcom_gen_bd_tx_reset(lpbfifo
.bcom_tx_task
);
466 out_be32(lpbfifo
.regs
+ LPBFIFO_REG_ENABLE
, 0x01010000);
469 spin_unlock_irqrestore(&lpbfifo
.lock
, flags
);
471 EXPORT_SYMBOL(mpc52xx_lpbfifo_abort
);
473 static int mpc52xx_lpbfifo_probe(struct platform_device
*op
)
478 if (lpbfifo
.dev
!= NULL
)
481 lpbfifo
.irq
= irq_of_parse_and_map(op
->dev
.of_node
, 0);
485 if (of_address_to_resource(op
->dev
.of_node
, 0, &res
))
487 lpbfifo
.regs_phys
= res
.start
;
488 lpbfifo
.regs
= of_iomap(op
->dev
.of_node
, 0);
492 spin_lock_init(&lpbfifo
.lock
);
494 /* Put FIFO into reset */
495 out_be32(lpbfifo
.regs
+ LPBFIFO_REG_ENABLE
, 0x01010000);
497 /* Register the interrupt handler */
498 rc
= request_irq(lpbfifo
.irq
, mpc52xx_lpbfifo_irq
, 0,
499 "mpc52xx-lpbfifo", &lpbfifo
);
503 /* Request the Bestcomm receive (fifo --> memory) task and IRQ */
504 lpbfifo
.bcom_rx_task
=
505 bcom_gen_bd_rx_init(2, res
.start
+ LPBFIFO_REG_FIFO_DATA
,
506 BCOM_INITIATOR_SCLPC
, BCOM_IPR_SCLPC
,
508 if (!lpbfifo
.bcom_rx_task
)
511 rc
= request_irq(bcom_get_task_irq(lpbfifo
.bcom_rx_task
),
512 mpc52xx_lpbfifo_bcom_irq
, 0,
513 "mpc52xx-lpbfifo-rx", &lpbfifo
);
515 goto err_bcom_rx_irq
;
517 lpbfifo
.dma_irqs_enabled
= 1;
519 /* Request the Bestcomm transmit (memory --> fifo) task and IRQ */
520 lpbfifo
.bcom_tx_task
=
521 bcom_gen_bd_tx_init(2, res
.start
+ LPBFIFO_REG_FIFO_DATA
,
522 BCOM_INITIATOR_SCLPC
, BCOM_IPR_SCLPC
);
523 if (!lpbfifo
.bcom_tx_task
)
526 lpbfifo
.dev
= &op
->dev
;
530 free_irq(bcom_get_task_irq(lpbfifo
.bcom_rx_task
), &lpbfifo
);
532 bcom_gen_bd_rx_release(lpbfifo
.bcom_rx_task
);
535 iounmap(lpbfifo
.regs
);
538 dev_err(&op
->dev
, "mpc52xx_lpbfifo_probe() failed\n");
543 static int mpc52xx_lpbfifo_remove(struct platform_device
*op
)
545 if (lpbfifo
.dev
!= &op
->dev
)
548 /* Put FIFO in reset */
549 out_be32(lpbfifo
.regs
+ LPBFIFO_REG_ENABLE
, 0x01010000);
551 /* Release the bestcomm transmit task */
552 free_irq(bcom_get_task_irq(lpbfifo
.bcom_tx_task
), &lpbfifo
);
553 bcom_gen_bd_tx_release(lpbfifo
.bcom_tx_task
);
555 /* Release the bestcomm receive task */
556 free_irq(bcom_get_task_irq(lpbfifo
.bcom_rx_task
), &lpbfifo
);
557 bcom_gen_bd_rx_release(lpbfifo
.bcom_rx_task
);
559 free_irq(lpbfifo
.irq
, &lpbfifo
);
560 iounmap(lpbfifo
.regs
);
567 static struct of_device_id mpc52xx_lpbfifo_match
[] = {
568 { .compatible
= "fsl,mpc5200-lpbfifo", },
572 static struct platform_driver mpc52xx_lpbfifo_driver
= {
574 .name
= "mpc52xx-lpbfifo",
575 .owner
= THIS_MODULE
,
576 .of_match_table
= mpc52xx_lpbfifo_match
,
578 .probe
= mpc52xx_lpbfifo_probe
,
579 .remove
= mpc52xx_lpbfifo_remove
,
581 module_platform_driver(mpc52xx_lpbfifo_driver
);