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ae918c02 AK |
1 | /* |
2 | * xilinx_spi.c | |
3 | * | |
4 | * Xilinx SPI controller driver (master mode only) | |
5 | * | |
6 | * Author: MontaVista Software, Inc. | |
7 | * source@mvista.com | |
8 | * | |
9 | * 2002-2007 (c) MontaVista Software, Inc. This file is licensed under the | |
10 | * terms of the GNU General Public License version 2. This program is licensed | |
11 | * "as is" without any warranty of any kind, whether express or implied. | |
12 | */ | |
13 | ||
14 | #include <linux/module.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/interrupt.h> | |
17 | #include <linux/platform_device.h> | |
ff82c587 JL |
18 | |
19 | #include <linux/of_platform.h> | |
20 | #include <linux/of_device.h> | |
21 | #include <linux/of_spi.h> | |
22 | ||
ae918c02 AK |
23 | #include <linux/spi/spi.h> |
24 | #include <linux/spi/spi_bitbang.h> | |
25 | #include <linux/io.h> | |
26 | ||
fc3ba952 | 27 | #define XILINX_SPI_NAME "xilinx_spi" |
ae918c02 AK |
28 | |
29 | /* Register definitions as per "OPB Serial Peripheral Interface (SPI) (v1.00e) | |
30 | * Product Specification", DS464 | |
31 | */ | |
32 | #define XSPI_CR_OFFSET 0x62 /* 16-bit Control Register */ | |
33 | ||
34 | #define XSPI_CR_ENABLE 0x02 | |
35 | #define XSPI_CR_MASTER_MODE 0x04 | |
36 | #define XSPI_CR_CPOL 0x08 | |
37 | #define XSPI_CR_CPHA 0x10 | |
38 | #define XSPI_CR_MODE_MASK (XSPI_CR_CPHA | XSPI_CR_CPOL) | |
39 | #define XSPI_CR_TXFIFO_RESET 0x20 | |
40 | #define XSPI_CR_RXFIFO_RESET 0x40 | |
41 | #define XSPI_CR_MANUAL_SSELECT 0x80 | |
42 | #define XSPI_CR_TRANS_INHIBIT 0x100 | |
43 | ||
44 | #define XSPI_SR_OFFSET 0x67 /* 8-bit Status Register */ | |
45 | ||
46 | #define XSPI_SR_RX_EMPTY_MASK 0x01 /* Receive FIFO is empty */ | |
47 | #define XSPI_SR_RX_FULL_MASK 0x02 /* Receive FIFO is full */ | |
48 | #define XSPI_SR_TX_EMPTY_MASK 0x04 /* Transmit FIFO is empty */ | |
49 | #define XSPI_SR_TX_FULL_MASK 0x08 /* Transmit FIFO is full */ | |
50 | #define XSPI_SR_MODE_FAULT_MASK 0x10 /* Mode fault error */ | |
51 | ||
52 | #define XSPI_TXD_OFFSET 0x6b /* 8-bit Data Transmit Register */ | |
53 | #define XSPI_RXD_OFFSET 0x6f /* 8-bit Data Receive Register */ | |
54 | ||
55 | #define XSPI_SSR_OFFSET 0x70 /* 32-bit Slave Select Register */ | |
56 | ||
57 | /* Register definitions as per "OPB IPIF (v3.01c) Product Specification", DS414 | |
58 | * IPIF registers are 32 bit | |
59 | */ | |
60 | #define XIPIF_V123B_DGIER_OFFSET 0x1c /* IPIF global int enable reg */ | |
61 | #define XIPIF_V123B_GINTR_ENABLE 0x80000000 | |
62 | ||
63 | #define XIPIF_V123B_IISR_OFFSET 0x20 /* IPIF interrupt status reg */ | |
64 | #define XIPIF_V123B_IIER_OFFSET 0x28 /* IPIF interrupt enable reg */ | |
65 | ||
66 | #define XSPI_INTR_MODE_FAULT 0x01 /* Mode fault error */ | |
67 | #define XSPI_INTR_SLAVE_MODE_FAULT 0x02 /* Selected as slave while | |
68 | * disabled */ | |
69 | #define XSPI_INTR_TX_EMPTY 0x04 /* TxFIFO is empty */ | |
70 | #define XSPI_INTR_TX_UNDERRUN 0x08 /* TxFIFO was underrun */ | |
71 | #define XSPI_INTR_RX_FULL 0x10 /* RxFIFO is full */ | |
72 | #define XSPI_INTR_RX_OVERRUN 0x20 /* RxFIFO was overrun */ | |
73 | ||
74 | #define XIPIF_V123B_RESETR_OFFSET 0x40 /* IPIF reset register */ | |
75 | #define XIPIF_V123B_RESET_MASK 0x0a /* the value to write */ | |
76 | ||
77 | struct xilinx_spi { | |
78 | /* bitbang has to be first */ | |
79 | struct spi_bitbang bitbang; | |
80 | struct completion done; | |
81 | ||
82 | void __iomem *regs; /* virt. address of the control registers */ | |
83 | ||
84 | u32 irq; | |
85 | ||
86 | u32 speed_hz; /* SCK has a fixed frequency of speed_hz Hz */ | |
87 | ||
88 | u8 *rx_ptr; /* pointer in the Tx buffer */ | |
89 | const u8 *tx_ptr; /* pointer in the Rx buffer */ | |
90 | int remaining_bytes; /* the number of bytes left to transfer */ | |
91 | }; | |
92 | ||
93 | static void xspi_init_hw(void __iomem *regs_base) | |
94 | { | |
95 | /* Reset the SPI device */ | |
96 | out_be32(regs_base + XIPIF_V123B_RESETR_OFFSET, | |
97 | XIPIF_V123B_RESET_MASK); | |
98 | /* Disable all the interrupts just in case */ | |
99 | out_be32(regs_base + XIPIF_V123B_IIER_OFFSET, 0); | |
100 | /* Enable the global IPIF interrupt */ | |
101 | out_be32(regs_base + XIPIF_V123B_DGIER_OFFSET, | |
102 | XIPIF_V123B_GINTR_ENABLE); | |
103 | /* Deselect the slave on the SPI bus */ | |
104 | out_be32(regs_base + XSPI_SSR_OFFSET, 0xffff); | |
105 | /* Disable the transmitter, enable Manual Slave Select Assertion, | |
106 | * put SPI controller into master mode, and enable it */ | |
107 | out_be16(regs_base + XSPI_CR_OFFSET, | |
108 | XSPI_CR_TRANS_INHIBIT | XSPI_CR_MANUAL_SSELECT | |
109 | | XSPI_CR_MASTER_MODE | XSPI_CR_ENABLE); | |
110 | } | |
111 | ||
112 | static void xilinx_spi_chipselect(struct spi_device *spi, int is_on) | |
113 | { | |
114 | struct xilinx_spi *xspi = spi_master_get_devdata(spi->master); | |
115 | ||
116 | if (is_on == BITBANG_CS_INACTIVE) { | |
117 | /* Deselect the slave on the SPI bus */ | |
118 | out_be32(xspi->regs + XSPI_SSR_OFFSET, 0xffff); | |
119 | } else if (is_on == BITBANG_CS_ACTIVE) { | |
120 | /* Set the SPI clock phase and polarity */ | |
121 | u16 cr = in_be16(xspi->regs + XSPI_CR_OFFSET) | |
122 | & ~XSPI_CR_MODE_MASK; | |
123 | if (spi->mode & SPI_CPHA) | |
124 | cr |= XSPI_CR_CPHA; | |
125 | if (spi->mode & SPI_CPOL) | |
126 | cr |= XSPI_CR_CPOL; | |
127 | out_be16(xspi->regs + XSPI_CR_OFFSET, cr); | |
128 | ||
129 | /* We do not check spi->max_speed_hz here as the SPI clock | |
130 | * frequency is not software programmable (the IP block design | |
131 | * parameter) | |
132 | */ | |
133 | ||
134 | /* Activate the chip select */ | |
135 | out_be32(xspi->regs + XSPI_SSR_OFFSET, | |
136 | ~(0x0001 << spi->chip_select)); | |
137 | } | |
138 | } | |
139 | ||
140 | /* spi_bitbang requires custom setup_transfer() to be defined if there is a | |
141 | * custom txrx_bufs(). We have nothing to setup here as the SPI IP block | |
142 | * supports just 8 bits per word, and SPI clock can't be changed in software. | |
143 | * Check for 8 bits per word. Chip select delay calculations could be | |
144 | * added here as soon as bitbang_work() can be made aware of the delay value. | |
145 | */ | |
146 | static int xilinx_spi_setup_transfer(struct spi_device *spi, | |
147 | struct spi_transfer *t) | |
148 | { | |
149 | u8 bits_per_word; | |
ae918c02 | 150 | |
1a8d3b77 JL |
151 | bits_per_word = (t && t->bits_per_word) |
152 | ? t->bits_per_word : spi->bits_per_word; | |
ae918c02 AK |
153 | if (bits_per_word != 8) { |
154 | dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n", | |
b687d2a8 | 155 | __func__, bits_per_word); |
ae918c02 AK |
156 | return -EINVAL; |
157 | } | |
158 | ||
ae918c02 AK |
159 | return 0; |
160 | } | |
161 | ||
ae918c02 AK |
162 | static int xilinx_spi_setup(struct spi_device *spi) |
163 | { | |
164 | struct spi_bitbang *bitbang; | |
165 | struct xilinx_spi *xspi; | |
166 | int retval; | |
167 | ||
168 | xspi = spi_master_get_devdata(spi->master); | |
169 | bitbang = &xspi->bitbang; | |
170 | ||
ae918c02 AK |
171 | retval = xilinx_spi_setup_transfer(spi, NULL); |
172 | if (retval < 0) | |
173 | return retval; | |
174 | ||
ae918c02 AK |
175 | return 0; |
176 | } | |
177 | ||
178 | static void xilinx_spi_fill_tx_fifo(struct xilinx_spi *xspi) | |
179 | { | |
180 | u8 sr; | |
181 | ||
182 | /* Fill the Tx FIFO with as many bytes as possible */ | |
183 | sr = in_8(xspi->regs + XSPI_SR_OFFSET); | |
184 | while ((sr & XSPI_SR_TX_FULL_MASK) == 0 && xspi->remaining_bytes > 0) { | |
185 | if (xspi->tx_ptr) { | |
186 | out_8(xspi->regs + XSPI_TXD_OFFSET, *xspi->tx_ptr++); | |
187 | } else { | |
188 | out_8(xspi->regs + XSPI_TXD_OFFSET, 0); | |
189 | } | |
190 | xspi->remaining_bytes--; | |
191 | sr = in_8(xspi->regs + XSPI_SR_OFFSET); | |
192 | } | |
193 | } | |
194 | ||
195 | static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t) | |
196 | { | |
197 | struct xilinx_spi *xspi = spi_master_get_devdata(spi->master); | |
198 | u32 ipif_ier; | |
199 | u16 cr; | |
200 | ||
201 | /* We get here with transmitter inhibited */ | |
202 | ||
203 | xspi->tx_ptr = t->tx_buf; | |
204 | xspi->rx_ptr = t->rx_buf; | |
205 | xspi->remaining_bytes = t->len; | |
206 | INIT_COMPLETION(xspi->done); | |
207 | ||
208 | xilinx_spi_fill_tx_fifo(xspi); | |
209 | ||
210 | /* Enable the transmit empty interrupt, which we use to determine | |
211 | * progress on the transmission. | |
212 | */ | |
213 | ipif_ier = in_be32(xspi->regs + XIPIF_V123B_IIER_OFFSET); | |
214 | out_be32(xspi->regs + XIPIF_V123B_IIER_OFFSET, | |
215 | ipif_ier | XSPI_INTR_TX_EMPTY); | |
216 | ||
217 | /* Start the transfer by not inhibiting the transmitter any longer */ | |
218 | cr = in_be16(xspi->regs + XSPI_CR_OFFSET) & ~XSPI_CR_TRANS_INHIBIT; | |
219 | out_be16(xspi->regs + XSPI_CR_OFFSET, cr); | |
220 | ||
221 | wait_for_completion(&xspi->done); | |
222 | ||
223 | /* Disable the transmit empty interrupt */ | |
224 | out_be32(xspi->regs + XIPIF_V123B_IIER_OFFSET, ipif_ier); | |
225 | ||
226 | return t->len - xspi->remaining_bytes; | |
227 | } | |
228 | ||
229 | ||
230 | /* This driver supports single master mode only. Hence Tx FIFO Empty | |
231 | * is the only interrupt we care about. | |
232 | * Receive FIFO Overrun, Transmit FIFO Underrun, Mode Fault, and Slave Mode | |
233 | * Fault are not to happen. | |
234 | */ | |
235 | static irqreturn_t xilinx_spi_irq(int irq, void *dev_id) | |
236 | { | |
237 | struct xilinx_spi *xspi = dev_id; | |
238 | u32 ipif_isr; | |
239 | ||
240 | /* Get the IPIF interrupts, and clear them immediately */ | |
241 | ipif_isr = in_be32(xspi->regs + XIPIF_V123B_IISR_OFFSET); | |
242 | out_be32(xspi->regs + XIPIF_V123B_IISR_OFFSET, ipif_isr); | |
243 | ||
244 | if (ipif_isr & XSPI_INTR_TX_EMPTY) { /* Transmission completed */ | |
245 | u16 cr; | |
246 | u8 sr; | |
247 | ||
248 | /* A transmit has just completed. Process received data and | |
249 | * check for more data to transmit. Always inhibit the | |
250 | * transmitter while the Isr refills the transmit register/FIFO, | |
251 | * or make sure it is stopped if we're done. | |
252 | */ | |
253 | cr = in_be16(xspi->regs + XSPI_CR_OFFSET); | |
254 | out_be16(xspi->regs + XSPI_CR_OFFSET, | |
255 | cr | XSPI_CR_TRANS_INHIBIT); | |
256 | ||
257 | /* Read out all the data from the Rx FIFO */ | |
258 | sr = in_8(xspi->regs + XSPI_SR_OFFSET); | |
259 | while ((sr & XSPI_SR_RX_EMPTY_MASK) == 0) { | |
260 | u8 data; | |
261 | ||
262 | data = in_8(xspi->regs + XSPI_RXD_OFFSET); | |
263 | if (xspi->rx_ptr) { | |
264 | *xspi->rx_ptr++ = data; | |
265 | } | |
266 | sr = in_8(xspi->regs + XSPI_SR_OFFSET); | |
267 | } | |
268 | ||
269 | /* See if there is more data to send */ | |
270 | if (xspi->remaining_bytes > 0) { | |
271 | xilinx_spi_fill_tx_fifo(xspi); | |
272 | /* Start the transfer by not inhibiting the | |
273 | * transmitter any longer | |
274 | */ | |
275 | out_be16(xspi->regs + XSPI_CR_OFFSET, cr); | |
276 | } else { | |
277 | /* No more data to send. | |
278 | * Indicate the transfer is completed. | |
279 | */ | |
280 | complete(&xspi->done); | |
281 | } | |
282 | } | |
283 | ||
284 | return IRQ_HANDLED; | |
285 | } | |
286 | ||
ff82c587 JL |
287 | static int __init xilinx_spi_of_probe(struct of_device *ofdev, |
288 | const struct of_device_id *match) | |
ae918c02 | 289 | { |
ae918c02 AK |
290 | struct spi_master *master; |
291 | struct xilinx_spi *xspi; | |
ff82c587 JL |
292 | struct resource r_irq_struct; |
293 | struct resource r_mem_struct; | |
294 | ||
295 | struct resource *r_irq = &r_irq_struct; | |
296 | struct resource *r_mem = &r_mem_struct; | |
297 | int rc = 0; | |
298 | const u32 *prop; | |
299 | int len; | |
ae918c02 AK |
300 | |
301 | /* Get resources(memory, IRQ) associated with the device */ | |
ff82c587 | 302 | master = spi_alloc_master(&ofdev->dev, sizeof(struct xilinx_spi)); |
ae918c02 AK |
303 | |
304 | if (master == NULL) { | |
305 | return -ENOMEM; | |
306 | } | |
307 | ||
ff82c587 | 308 | dev_set_drvdata(&ofdev->dev, master); |
ae918c02 | 309 | |
ff82c587 JL |
310 | rc = of_address_to_resource(ofdev->node, 0, r_mem); |
311 | if (rc) { | |
312 | dev_warn(&ofdev->dev, "invalid address\n"); | |
ae918c02 AK |
313 | goto put_master; |
314 | } | |
315 | ||
ff82c587 JL |
316 | rc = of_irq_to_resource(ofdev->node, 0, r_irq); |
317 | if (rc == NO_IRQ) { | |
318 | dev_warn(&ofdev->dev, "no IRQ found\n"); | |
ae918c02 AK |
319 | goto put_master; |
320 | } | |
321 | ||
e7db06b5 DB |
322 | /* the spi->mode bits understood by this driver: */ |
323 | master->mode_bits = SPI_CPOL | SPI_CPHA; | |
324 | ||
ae918c02 AK |
325 | xspi = spi_master_get_devdata(master); |
326 | xspi->bitbang.master = spi_master_get(master); | |
327 | xspi->bitbang.chipselect = xilinx_spi_chipselect; | |
328 | xspi->bitbang.setup_transfer = xilinx_spi_setup_transfer; | |
329 | xspi->bitbang.txrx_bufs = xilinx_spi_txrx_bufs; | |
330 | xspi->bitbang.master->setup = xilinx_spi_setup; | |
331 | init_completion(&xspi->done); | |
332 | ||
ff82c587 JL |
333 | xspi->irq = r_irq->start; |
334 | ||
335 | if (!request_mem_region(r_mem->start, | |
336 | r_mem->end - r_mem->start + 1, XILINX_SPI_NAME)) { | |
337 | rc = -ENXIO; | |
338 | dev_warn(&ofdev->dev, "memory request failure\n"); | |
ae918c02 AK |
339 | goto put_master; |
340 | } | |
341 | ||
ff82c587 | 342 | xspi->regs = ioremap(r_mem->start, r_mem->end - r_mem->start + 1); |
ae918c02 | 343 | if (xspi->regs == NULL) { |
ff82c587 JL |
344 | rc = -ENOMEM; |
345 | dev_warn(&ofdev->dev, "ioremap failure\n"); | |
1df879e4 | 346 | goto release_mem; |
ae918c02 | 347 | } |
ff82c587 | 348 | xspi->irq = r_irq->start; |
ae918c02 | 349 | |
ff82c587 JL |
350 | /* dynamic bus assignment */ |
351 | master->bus_num = -1; | |
ae918c02 | 352 | |
ff82c587 JL |
353 | /* number of slave select bits is required */ |
354 | prop = of_get_property(ofdev->node, "xlnx,num-ss-bits", &len); | |
355 | if (!prop || len < sizeof(*prop)) { | |
356 | dev_warn(&ofdev->dev, "no 'xlnx,num-ss-bits' property\n"); | |
1df879e4 | 357 | goto unmap_io; |
ff82c587 JL |
358 | } |
359 | master->num_chipselect = *prop; | |
ae918c02 AK |
360 | |
361 | /* SPI controller initializations */ | |
362 | xspi_init_hw(xspi->regs); | |
363 | ||
364 | /* Register for SPI Interrupt */ | |
ff82c587 JL |
365 | rc = request_irq(xspi->irq, xilinx_spi_irq, 0, XILINX_SPI_NAME, xspi); |
366 | if (rc != 0) { | |
367 | dev_warn(&ofdev->dev, "irq request failure: %d\n", xspi->irq); | |
ae918c02 | 368 | goto unmap_io; |
ff82c587 | 369 | } |
ae918c02 | 370 | |
ff82c587 JL |
371 | rc = spi_bitbang_start(&xspi->bitbang); |
372 | if (rc != 0) { | |
373 | dev_err(&ofdev->dev, "spi_bitbang_start FAILED\n"); | |
ae918c02 AK |
374 | goto free_irq; |
375 | } | |
376 | ||
ff82c587 JL |
377 | dev_info(&ofdev->dev, "at 0x%08X mapped to 0x%08X, irq=%d\n", |
378 | (unsigned int)r_mem->start, (u32)xspi->regs, xspi->irq); | |
ae918c02 | 379 | |
ff82c587 JL |
380 | /* Add any subnodes on the SPI bus */ |
381 | of_register_spi_devices(master, ofdev->node); | |
382 | ||
383 | return rc; | |
ae918c02 AK |
384 | |
385 | free_irq: | |
386 | free_irq(xspi->irq, xspi); | |
387 | unmap_io: | |
388 | iounmap(xspi->regs); | |
1df879e4 JL |
389 | release_mem: |
390 | release_mem_region(r_mem->start, resource_size(r_mem)); | |
ae918c02 AK |
391 | put_master: |
392 | spi_master_put(master); | |
ff82c587 | 393 | return rc; |
ae918c02 AK |
394 | } |
395 | ||
ff82c587 | 396 | static int __devexit xilinx_spi_remove(struct of_device *ofdev) |
ae918c02 AK |
397 | { |
398 | struct xilinx_spi *xspi; | |
399 | struct spi_master *master; | |
1df879e4 | 400 | struct resource r_mem; |
ae918c02 | 401 | |
ff82c587 | 402 | master = platform_get_drvdata(ofdev); |
ae918c02 AK |
403 | xspi = spi_master_get_devdata(master); |
404 | ||
405 | spi_bitbang_stop(&xspi->bitbang); | |
406 | free_irq(xspi->irq, xspi); | |
407 | iounmap(xspi->regs); | |
1df879e4 JL |
408 | if (!of_address_to_resource(ofdev->node, 0, &r_mem)) |
409 | release_mem_region(r_mem.start, resource_size(&r_mem)); | |
ff82c587 | 410 | dev_set_drvdata(&ofdev->dev, 0); |
ae918c02 AK |
411 | spi_master_put(xspi->bitbang.master); |
412 | ||
413 | return 0; | |
414 | } | |
415 | ||
7e38c3c4 KS |
416 | /* work with hotplug and coldplug */ |
417 | MODULE_ALIAS("platform:" XILINX_SPI_NAME); | |
418 | ||
ff82c587 JL |
419 | static int __exit xilinx_spi_of_remove(struct of_device *op) |
420 | { | |
421 | return xilinx_spi_remove(op); | |
422 | } | |
423 | ||
424 | static struct of_device_id xilinx_spi_of_match[] = { | |
425 | { .compatible = "xlnx,xps-spi-2.00.a", }, | |
426 | { .compatible = "xlnx,xps-spi-2.00.b", }, | |
427 | {} | |
428 | }; | |
429 | ||
430 | MODULE_DEVICE_TABLE(of, xilinx_spi_of_match); | |
431 | ||
432 | static struct of_platform_driver xilinx_spi_of_driver = { | |
433 | .owner = THIS_MODULE, | |
434 | .name = "xilinx-xps-spi", | |
435 | .match_table = xilinx_spi_of_match, | |
436 | .probe = xilinx_spi_of_probe, | |
437 | .remove = __exit_p(xilinx_spi_of_remove), | |
ae918c02 | 438 | .driver = { |
ff82c587 | 439 | .name = "xilinx-xps-spi", |
ae918c02 AK |
440 | .owner = THIS_MODULE, |
441 | }, | |
442 | }; | |
443 | ||
444 | static int __init xilinx_spi_init(void) | |
445 | { | |
ff82c587 | 446 | return of_register_platform_driver(&xilinx_spi_of_driver); |
ae918c02 AK |
447 | } |
448 | module_init(xilinx_spi_init); | |
449 | ||
450 | static void __exit xilinx_spi_exit(void) | |
451 | { | |
ff82c587 | 452 | of_unregister_platform_driver(&xilinx_spi_of_driver); |
ae918c02 AK |
453 | } |
454 | module_exit(xilinx_spi_exit); | |
ae918c02 AK |
455 | MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>"); |
456 | MODULE_DESCRIPTION("Xilinx SPI driver"); | |
457 | MODULE_LICENSE("GPL"); |