2 * Driver for Nvidia TEGRA spi controller.
4 * Copyright (C) 2010 Google, Inc.
7 * Erik Gilling <konkers@android.com>
9 * This software is licensed under the terms of the GNU General Public
10 * License version 2, as published by the Free Software Foundation, and
11 * may be copied, distributed, and modified under those terms.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/init.h>
23 #include <linux/err.h>
24 #include <linux/platform_device.h>
26 #include <linux/dma-mapping.h>
27 #include <linux/dmapool.h>
28 #include <linux/clk.h>
29 #include <linux/interrupt.h>
30 #include <linux/delay.h>
32 #include <linux/spi/spi.h>
36 #define SLINK_COMMAND 0x000
37 #define SLINK_BIT_LENGTH(x) (((x) & 0x1f) << 0)
38 #define SLINK_WORD_SIZE(x) (((x) & 0x1f) << 5)
39 #define SLINK_BOTH_EN (1 << 10)
40 #define SLINK_CS_SW (1 << 11)
41 #define SLINK_CS_VALUE (1 << 12)
42 #define SLINK_CS_POLARITY (1 << 13)
43 #define SLINK_IDLE_SDA_DRIVE_LOW (0 << 16)
44 #define SLINK_IDLE_SDA_DRIVE_HIGH (1 << 16)
45 #define SLINK_IDLE_SDA_PULL_LOW (2 << 16)
46 #define SLINK_IDLE_SDA_PULL_HIGH (3 << 16)
47 #define SLINK_IDLE_SDA_MASK (3 << 16)
48 #define SLINK_CS_POLARITY1 (1 << 20)
49 #define SLINK_CK_SDA (1 << 21)
50 #define SLINK_CS_POLARITY2 (1 << 22)
51 #define SLINK_CS_POLARITY3 (1 << 23)
52 #define SLINK_IDLE_SCLK_DRIVE_LOW (0 << 24)
53 #define SLINK_IDLE_SCLK_DRIVE_HIGH (1 << 24)
54 #define SLINK_IDLE_SCLK_PULL_LOW (2 << 24)
55 #define SLINK_IDLE_SCLK_PULL_HIGH (3 << 24)
56 #define SLINK_IDLE_SCLK_MASK (3 << 24)
57 #define SLINK_M_S (1 << 28)
58 #define SLINK_WAIT (1 << 29)
59 #define SLINK_GO (1 << 30)
60 #define SLINK_ENB (1 << 31)
62 #define SLINK_COMMAND2 0x004
63 #define SLINK_LSBFE (1 << 0)
64 #define SLINK_SSOE (1 << 1)
65 #define SLINK_SPIE (1 << 4)
66 #define SLINK_BIDIROE (1 << 6)
67 #define SLINK_MODFEN (1 << 7)
68 #define SLINK_INT_SIZE(x) (((x) & 0x1f) << 8)
69 #define SLINK_CS_ACTIVE_BETWEEN (1 << 17)
70 #define SLINK_SS_EN_CS(x) (((x) & 0x3) << 18)
71 #define SLINK_SS_SETUP(x) (((x) & 0x3) << 20)
72 #define SLINK_FIFO_REFILLS_0 (0 << 22)
73 #define SLINK_FIFO_REFILLS_1 (1 << 22)
74 #define SLINK_FIFO_REFILLS_2 (2 << 22)
75 #define SLINK_FIFO_REFILLS_3 (3 << 22)
76 #define SLINK_FIFO_REFILLS_MASK (3 << 22)
77 #define SLINK_WAIT_PACK_INT(x) (((x) & 0x7) << 26)
78 #define SLINK_SPC0 (1 << 29)
79 #define SLINK_TXEN (1 << 30)
80 #define SLINK_RXEN (1 << 31)
82 #define SLINK_STATUS 0x008
83 #define SLINK_COUNT(val) (((val) >> 0) & 0x1f)
84 #define SLINK_WORD(val) (((val) >> 5) & 0x1f)
85 #define SLINK_BLK_CNT(val) (((val) >> 0) & 0xffff)
86 #define SLINK_MODF (1 << 16)
87 #define SLINK_RX_UNF (1 << 18)
88 #define SLINK_TX_OVF (1 << 19)
89 #define SLINK_TX_FULL (1 << 20)
90 #define SLINK_TX_EMPTY (1 << 21)
91 #define SLINK_RX_FULL (1 << 22)
92 #define SLINK_RX_EMPTY (1 << 23)
93 #define SLINK_TX_UNF (1 << 24)
94 #define SLINK_RX_OVF (1 << 25)
95 #define SLINK_TX_FLUSH (1 << 26)
96 #define SLINK_RX_FLUSH (1 << 27)
97 #define SLINK_SCLK (1 << 28)
98 #define SLINK_ERR (1 << 29)
99 #define SLINK_RDY (1 << 30)
100 #define SLINK_BSY (1 << 31)
102 #define SLINK_MAS_DATA 0x010
103 #define SLINK_SLAVE_DATA 0x014
105 #define SLINK_DMA_CTL 0x018
106 #define SLINK_DMA_BLOCK_SIZE(x) (((x) & 0xffff) << 0)
107 #define SLINK_TX_TRIG_1 (0 << 16)
108 #define SLINK_TX_TRIG_4 (1 << 16)
109 #define SLINK_TX_TRIG_8 (2 << 16)
110 #define SLINK_TX_TRIG_16 (3 << 16)
111 #define SLINK_TX_TRIG_MASK (3 << 16)
112 #define SLINK_RX_TRIG_1 (0 << 18)
113 #define SLINK_RX_TRIG_4 (1 << 18)
114 #define SLINK_RX_TRIG_8 (2 << 18)
115 #define SLINK_RX_TRIG_16 (3 << 18)
116 #define SLINK_RX_TRIG_MASK (3 << 18)
117 #define SLINK_PACKED (1 << 20)
118 #define SLINK_PACK_SIZE_4 (0 << 21)
119 #define SLINK_PACK_SIZE_8 (1 << 21)
120 #define SLINK_PACK_SIZE_16 (2 << 21)
121 #define SLINK_PACK_SIZE_32 (3 << 21)
122 #define SLINK_PACK_SIZE_MASK (3 << 21)
123 #define SLINK_IE_TXC (1 << 26)
124 #define SLINK_IE_RXC (1 << 27)
125 #define SLINK_DMA_EN (1 << 31)
127 #define SLINK_STATUS2 0x01c
128 #define SLINK_TX_FIFO_EMPTY_COUNT(val) (((val) & 0x3f) >> 0)
129 #define SLINK_RX_FIFO_FULL_COUNT(val) (((val) & 0x3f) >> 16)
131 #define SLINK_TX_FIFO 0x100
132 #define SLINK_RX_FIFO 0x180
134 static const unsigned long spi_tegra_req_sels
[] = {
135 TEGRA_DMA_REQ_SEL_SL2B1
,
136 TEGRA_DMA_REQ_SEL_SL2B2
,
137 TEGRA_DMA_REQ_SEL_SL2B3
,
138 TEGRA_DMA_REQ_SEL_SL2B4
,
143 struct spi_tegra_data
{
144 struct spi_master
*master
;
145 struct platform_device
*pdev
;
154 struct list_head queue
;
155 struct spi_transfer
*cur
;
158 unsigned cur_bytes_per_word
;
160 /* The tegra spi controller has a bug which causes the first word
161 * in PIO transactions to be garbage. Since packed DMA transactions
162 * require transfers to be 4 byte aligned we need a bounce buffer
163 * for the generic case.
165 struct tegra_dma_req rx_dma_req
;
166 struct tegra_dma_channel
*rx_dma
;
168 dma_addr_t rx_bb_phys
;
172 static inline unsigned long spi_tegra_readl(struct spi_tegra_data
*tspi
,
175 return readl(tspi
->base
+ reg
);
178 static inline void spi_tegra_writel(struct spi_tegra_data
*tspi
,
182 writel(val
, tspi
->base
+ reg
);
185 static void spi_tegra_go(struct spi_tegra_data
*tspi
)
191 val
= spi_tegra_readl(tspi
, SLINK_DMA_CTL
);
192 val
&= ~SLINK_DMA_BLOCK_SIZE(~0) & ~SLINK_DMA_EN
;
193 val
|= SLINK_DMA_BLOCK_SIZE(tspi
->rx_dma_req
.size
/ 4 - 1);
194 spi_tegra_writel(tspi
, val
, SLINK_DMA_CTL
);
196 tegra_dma_enqueue_req(tspi
->rx_dma
, &tspi
->rx_dma_req
);
199 spi_tegra_writel(tspi
, val
, SLINK_DMA_CTL
);
202 static unsigned spi_tegra_fill_tx_fifo(struct spi_tegra_data
*tspi
,
203 struct spi_transfer
*t
)
205 unsigned len
= min(t
->len
- tspi
->cur_pos
, BB_LEN
*
206 tspi
->cur_bytes_per_word
);
207 u8
*tx_buf
= (u8
*)t
->tx_buf
+ tspi
->cur_pos
;
211 val
= spi_tegra_readl(tspi
, SLINK_COMMAND
);
212 val
&= ~SLINK_WORD_SIZE(~0);
213 val
|= SLINK_WORD_SIZE(len
/ tspi
->cur_bytes_per_word
- 1);
214 spi_tegra_writel(tspi
, val
, SLINK_COMMAND
);
216 for (i
= 0; i
< len
; i
+= tspi
->cur_bytes_per_word
) {
218 for (j
= 0; j
< tspi
->cur_bytes_per_word
; j
++)
219 val
|= tx_buf
[i
+ j
] << j
* 8;
221 spi_tegra_writel(tspi
, val
, SLINK_TX_FIFO
);
224 tspi
->rx_dma_req
.size
= len
/ tspi
->cur_bytes_per_word
* 4;
229 static unsigned spi_tegra_drain_rx_fifo(struct spi_tegra_data
*tspi
,
230 struct spi_transfer
*t
)
232 unsigned len
= tspi
->cur_len
;
233 u8
*rx_buf
= (u8
*)t
->rx_buf
+ tspi
->cur_pos
;
237 for (i
= 0; i
< len
; i
+= tspi
->cur_bytes_per_word
) {
238 val
= tspi
->rx_bb
[i
/ tspi
->cur_bytes_per_word
];
239 for (j
= 0; j
< tspi
->cur_bytes_per_word
; j
++)
240 rx_buf
[i
+ j
] = (val
>> (j
* 8)) & 0xff;
246 static void spi_tegra_start_transfer(struct spi_device
*spi
,
247 struct spi_transfer
*t
)
249 struct spi_tegra_data
*tspi
= spi_master_get_devdata(spi
->master
);
254 speed
= t
->speed_hz
? t
->speed_hz
: spi
->max_speed_hz
;
255 bits_per_word
= t
->bits_per_word
? t
->bits_per_word
:
258 tspi
->cur_bytes_per_word
= (bits_per_word
- 1) / 8 + 1;
260 if (speed
!= tspi
->cur_speed
)
261 clk_set_rate(tspi
->clk
, speed
);
263 if (tspi
->cur_speed
== 0)
264 clk_enable(tspi
->clk
);
266 tspi
->cur_speed
= speed
;
268 val
= spi_tegra_readl(tspi
, SLINK_COMMAND2
);
269 val
&= ~SLINK_SS_EN_CS(~0) | SLINK_RXEN
| SLINK_TXEN
;
274 val
|= SLINK_SS_EN_CS(spi
->chip_select
);
276 spi_tegra_writel(tspi
, val
, SLINK_COMMAND2
);
278 val
= spi_tegra_readl(tspi
, SLINK_COMMAND
);
279 val
&= ~SLINK_BIT_LENGTH(~0);
280 val
|= SLINK_BIT_LENGTH(bits_per_word
- 1);
282 /* FIXME: should probably control CS manually so that we can be sure
283 * it does not go low between transfer and to support delay_usecs
286 val
&= ~SLINK_IDLE_SCLK_MASK
& ~SLINK_CK_SDA
& ~SLINK_CS_SW
;
288 if (spi
->mode
& SPI_CPHA
)
291 if (spi
->mode
& SPI_CPOL
)
292 val
|= SLINK_IDLE_SCLK_DRIVE_HIGH
;
294 val
|= SLINK_IDLE_SCLK_DRIVE_LOW
;
298 spi_tegra_writel(tspi
, val
, SLINK_COMMAND
);
300 spi_tegra_writel(tspi
, SLINK_RX_FLUSH
| SLINK_TX_FLUSH
, SLINK_STATUS
);
304 tspi
->cur_len
= spi_tegra_fill_tx_fifo(tspi
, t
);
309 static void spi_tegra_start_message(struct spi_device
*spi
,
310 struct spi_message
*m
)
312 struct spi_transfer
*t
;
314 m
->actual_length
= 0;
317 t
= list_first_entry(&m
->transfers
, struct spi_transfer
, transfer_list
);
318 spi_tegra_start_transfer(spi
, t
);
321 static void tegra_spi_rx_dma_complete(struct tegra_dma_req
*req
)
323 struct spi_tegra_data
*tspi
= req
->dev
;
325 struct spi_message
*m
;
326 struct spi_device
*spi
;
330 /* the SPI controller may come back with both the BSY and RDY bits
331 * set. In this case we need to wait for the BSY bit to clear so
332 * that we are sure the DMA is finished. 1000 reads was empirically
333 * determined to be long enough.
335 while (timeout
++ < 1000) {
336 if (!(spi_tegra_readl(tspi
, SLINK_STATUS
) & SLINK_BSY
))
340 spin_lock_irqsave(&tspi
->lock
, flags
);
342 val
= spi_tegra_readl(tspi
, SLINK_STATUS
);
344 spi_tegra_writel(tspi
, val
, SLINK_STATUS
);
346 m
= list_first_entry(&tspi
->queue
, struct spi_message
, queue
);
353 tspi
->cur_pos
+= spi_tegra_drain_rx_fifo(tspi
, tspi
->cur
);
354 m
->actual_length
+= tspi
->cur_pos
;
356 if (tspi
->cur_pos
< tspi
->cur
->len
) {
357 tspi
->cur_len
= spi_tegra_fill_tx_fifo(tspi
, tspi
->cur
);
359 } else if (!list_is_last(&tspi
->cur
->transfer_list
,
361 tspi
->cur
= list_first_entry(&tspi
->cur
->transfer_list
,
364 spi_tegra_start_transfer(spi
, tspi
->cur
);
368 m
->complete(m
->context
);
370 if (!list_empty(&tspi
->queue
)) {
371 m
= list_first_entry(&tspi
->queue
, struct spi_message
,
374 spi_tegra_start_message(spi
, m
);
376 clk_disable(tspi
->clk
);
381 spin_unlock_irqrestore(&tspi
->lock
, flags
);
384 static int spi_tegra_setup(struct spi_device
*spi
)
386 struct spi_tegra_data
*tspi
= spi_master_get_devdata(spi
->master
);
387 unsigned long cs_bit
;
391 dev_dbg(&spi
->dev
, "setup %d bpw, %scpol, %scpha, %dHz\n",
393 spi
->mode
& SPI_CPOL
? "" : "~",
394 spi
->mode
& SPI_CPHA
? "" : "~",
398 switch (spi
->chip_select
) {
400 cs_bit
= SLINK_CS_POLARITY
;
404 cs_bit
= SLINK_CS_POLARITY1
;
408 cs_bit
= SLINK_CS_POLARITY2
;
412 cs_bit
= SLINK_CS_POLARITY3
;
419 spin_lock_irqsave(&tspi
->lock
, flags
);
421 val
= spi_tegra_readl(tspi
, SLINK_COMMAND
);
422 if (spi
->mode
& SPI_CS_HIGH
)
426 spi_tegra_writel(tspi
, val
, SLINK_COMMAND
);
428 spin_unlock_irqrestore(&tspi
->lock
, flags
);
433 static int spi_tegra_transfer(struct spi_device
*spi
, struct spi_message
*m
)
435 struct spi_tegra_data
*tspi
= spi_master_get_devdata(spi
->master
);
436 struct spi_transfer
*t
;
440 if (list_empty(&m
->transfers
) || !m
->complete
)
443 list_for_each_entry(t
, &m
->transfers
, transfer_list
) {
444 if (t
->bits_per_word
< 0 || t
->bits_per_word
> 32)
450 if (!t
->rx_buf
&& !t
->tx_buf
)
456 spin_lock_irqsave(&tspi
->lock
, flags
);
457 was_empty
= list_empty(&tspi
->queue
);
458 list_add_tail(&m
->queue
, &tspi
->queue
);
461 spi_tegra_start_message(spi
, m
);
463 spin_unlock_irqrestore(&tspi
->lock
, flags
);
468 static int __devinit
spi_tegra_probe(struct platform_device
*pdev
)
470 struct spi_master
*master
;
471 struct spi_tegra_data
*tspi
;
475 master
= spi_alloc_master(&pdev
->dev
, sizeof *tspi
);
476 if (master
== NULL
) {
477 dev_err(&pdev
->dev
, "master allocation failed\n");
481 /* the spi->mode bits understood by this driver: */
482 master
->mode_bits
= SPI_CPOL
| SPI_CPHA
| SPI_CS_HIGH
;
484 master
->bus_num
= pdev
->id
;
486 master
->setup
= spi_tegra_setup
;
487 master
->transfer
= spi_tegra_transfer
;
488 master
->num_chipselect
= 4;
490 dev_set_drvdata(&pdev
->dev
, master
);
491 tspi
= spi_master_get_devdata(master
);
492 tspi
->master
= master
;
494 spin_lock_init(&tspi
->lock
);
496 r
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
502 if (!request_mem_region(r
->start
, resource_size(r
),
503 dev_name(&pdev
->dev
))) {
508 tspi
->phys
= r
->start
;
509 tspi
->base
= ioremap(r
->start
, resource_size(r
));
511 dev_err(&pdev
->dev
, "can't ioremap iomem\n");
516 tspi
->clk
= clk_get(&pdev
->dev
, NULL
);
517 if (IS_ERR(tspi
->clk
)) {
518 dev_err(&pdev
->dev
, "can not get clock\n");
519 ret
= PTR_ERR(tspi
->clk
);
523 INIT_LIST_HEAD(&tspi
->queue
);
525 tspi
->rx_dma
= tegra_dma_allocate_channel(TEGRA_DMA_MODE_ONESHOT
);
527 dev_err(&pdev
->dev
, "can not allocate rx dma channel\n");
532 tspi
->rx_bb
= dma_alloc_coherent(&pdev
->dev
, sizeof(u32
) * BB_LEN
,
533 &tspi
->rx_bb_phys
, GFP_KERNEL
);
535 dev_err(&pdev
->dev
, "can not allocate rx bounce buffer\n");
540 tspi
->rx_dma_req
.complete
= tegra_spi_rx_dma_complete
;
541 tspi
->rx_dma_req
.to_memory
= 1;
542 tspi
->rx_dma_req
.dest_addr
= tspi
->rx_bb_phys
;
543 tspi
->rx_dma_req
.dest_bus_width
= 32;
544 tspi
->rx_dma_req
.source_addr
= tspi
->phys
+ SLINK_RX_FIFO
;
545 tspi
->rx_dma_req
.source_bus_width
= 32;
546 tspi
->rx_dma_req
.source_wrap
= 4;
547 tspi
->rx_dma_req
.req_sel
= spi_tegra_req_sels
[pdev
->id
];
548 tspi
->rx_dma_req
.dev
= tspi
;
550 master
->dev
.of_node
= pdev
->dev
.of_node
;
551 ret
= spi_register_master(master
);
559 dma_free_coherent(&pdev
->dev
, sizeof(u32
) * BB_LEN
,
560 tspi
->rx_bb
, tspi
->rx_bb_phys
);
562 tegra_dma_free_channel(tspi
->rx_dma
);
568 release_mem_region(r
->start
, resource_size(r
));
570 spi_master_put(master
);
574 static int __devexit
spi_tegra_remove(struct platform_device
*pdev
)
576 struct spi_master
*master
;
577 struct spi_tegra_data
*tspi
;
580 master
= dev_get_drvdata(&pdev
->dev
);
581 tspi
= spi_master_get_devdata(master
);
583 spi_unregister_master(master
);
584 tegra_dma_free_channel(tspi
->rx_dma
);
586 dma_free_coherent(&pdev
->dev
, sizeof(u32
) * BB_LEN
,
587 tspi
->rx_bb
, tspi
->rx_bb_phys
);
592 r
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
593 release_mem_region(r
->start
, resource_size(r
));
598 MODULE_ALIAS("platform:spi_tegra");
601 static struct of_device_id spi_tegra_of_match_table
[] __devinitdata
= {
602 { .compatible
= "nvidia,tegra20-spi", },
605 MODULE_DEVICE_TABLE(of
, spi_tegra_of_match_table
);
606 #else /* CONFIG_OF */
607 #define spi_tegra_of_match_table NULL
608 #endif /* CONFIG_OF */
610 static struct platform_driver spi_tegra_driver
= {
613 .owner
= THIS_MODULE
,
614 .of_match_table
= spi_tegra_of_match_table
,
616 .probe
= spi_tegra_probe
,
617 .remove
= __devexit_p(spi_tegra_remove
),
619 module_platform_driver(spi_tegra_driver
);
621 MODULE_LICENSE("GPL");