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5928808e MW |
1 | /* |
2 | * PXA2xx SPI DMA engine support. | |
3 | * | |
4 | * Copyright (C) 2013, Intel Corporation | |
5 | * Author: Mika Westerberg <mika.westerberg@linux.intel.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | */ | |
11 | ||
5928808e MW |
12 | #include <linux/device.h> |
13 | #include <linux/dma-mapping.h> | |
14 | #include <linux/dmaengine.h> | |
15 | #include <linux/pxa2xx_ssp.h> | |
16 | #include <linux/scatterlist.h> | |
17 | #include <linux/sizes.h> | |
18 | #include <linux/spi/spi.h> | |
19 | #include <linux/spi/pxa2xx_spi.h> | |
20 | ||
21 | #include "spi-pxa2xx.h" | |
22 | ||
23 | static int pxa2xx_spi_map_dma_buffer(struct driver_data *drv_data, | |
24 | enum dma_data_direction dir) | |
25 | { | |
26 | int i, nents, len = drv_data->len; | |
27 | struct scatterlist *sg; | |
28 | struct device *dmadev; | |
29 | struct sg_table *sgt; | |
30 | void *buf, *pbuf; | |
31 | ||
5928808e MW |
32 | if (dir == DMA_TO_DEVICE) { |
33 | dmadev = drv_data->tx_chan->device->dev; | |
34 | sgt = &drv_data->tx_sgt; | |
35 | buf = drv_data->tx; | |
36 | drv_data->tx_map_len = len; | |
37 | } else { | |
38 | dmadev = drv_data->rx_chan->device->dev; | |
39 | sgt = &drv_data->rx_sgt; | |
40 | buf = drv_data->rx; | |
41 | drv_data->rx_map_len = len; | |
42 | } | |
43 | ||
44 | nents = DIV_ROUND_UP(len, SZ_2K); | |
45 | if (nents != sgt->nents) { | |
46 | int ret; | |
47 | ||
48 | sg_free_table(sgt); | |
5548f98c | 49 | ret = sg_alloc_table(sgt, nents, GFP_ATOMIC); |
5928808e MW |
50 | if (ret) |
51 | return ret; | |
52 | } | |
53 | ||
54 | pbuf = buf; | |
55 | for_each_sg(sgt->sgl, sg, sgt->nents, i) { | |
56 | size_t bytes = min_t(size_t, len, SZ_2K); | |
57 | ||
58 | if (buf) | |
59 | sg_set_buf(sg, pbuf, bytes); | |
60 | else | |
61 | sg_set_buf(sg, drv_data->dummy, bytes); | |
62 | ||
63 | pbuf += bytes; | |
64 | len -= bytes; | |
65 | } | |
66 | ||
67 | nents = dma_map_sg(dmadev, sgt->sgl, sgt->nents, dir); | |
68 | if (!nents) | |
69 | return -ENOMEM; | |
70 | ||
71 | return nents; | |
72 | } | |
73 | ||
74 | static void pxa2xx_spi_unmap_dma_buffer(struct driver_data *drv_data, | |
75 | enum dma_data_direction dir) | |
76 | { | |
77 | struct device *dmadev; | |
78 | struct sg_table *sgt; | |
79 | ||
80 | if (dir == DMA_TO_DEVICE) { | |
81 | dmadev = drv_data->tx_chan->device->dev; | |
82 | sgt = &drv_data->tx_sgt; | |
83 | } else { | |
84 | dmadev = drv_data->rx_chan->device->dev; | |
85 | sgt = &drv_data->rx_sgt; | |
86 | } | |
87 | ||
88 | dma_unmap_sg(dmadev, sgt->sgl, sgt->nents, dir); | |
89 | } | |
90 | ||
91 | static void pxa2xx_spi_unmap_dma_buffers(struct driver_data *drv_data) | |
92 | { | |
93 | if (!drv_data->dma_mapped) | |
94 | return; | |
95 | ||
96 | pxa2xx_spi_unmap_dma_buffer(drv_data, DMA_FROM_DEVICE); | |
97 | pxa2xx_spi_unmap_dma_buffer(drv_data, DMA_TO_DEVICE); | |
98 | ||
99 | drv_data->dma_mapped = 0; | |
100 | } | |
101 | ||
102 | static void pxa2xx_spi_dma_transfer_complete(struct driver_data *drv_data, | |
103 | bool error) | |
104 | { | |
105 | struct spi_message *msg = drv_data->cur_msg; | |
106 | ||
107 | /* | |
108 | * It is possible that one CPU is handling ROR interrupt and other | |
109 | * just gets DMA completion. Calling pump_transfers() twice for the | |
110 | * same transfer leads to problems thus we prevent concurrent calls | |
111 | * by using ->dma_running. | |
112 | */ | |
113 | if (atomic_dec_and_test(&drv_data->dma_running)) { | |
114 | void __iomem *reg = drv_data->ioaddr; | |
115 | ||
116 | /* | |
117 | * If the other CPU is still handling the ROR interrupt we | |
118 | * might not know about the error yet. So we re-check the | |
119 | * ROR bit here before we clear the status register. | |
120 | */ | |
121 | if (!error) { | |
122 | u32 status = read_SSSR(reg) & drv_data->mask_sr; | |
123 | error = status & SSSR_ROR; | |
124 | } | |
125 | ||
126 | /* Clear status & disable interrupts */ | |
127 | write_SSCR1(read_SSCR1(reg) & ~drv_data->dma_cr1, reg); | |
128 | write_SSSR_CS(drv_data, drv_data->clear_sr); | |
129 | if (!pxa25x_ssp_comp(drv_data)) | |
130 | write_SSTO(0, reg); | |
131 | ||
132 | if (!error) { | |
133 | pxa2xx_spi_unmap_dma_buffers(drv_data); | |
134 | ||
5928808e | 135 | drv_data->tx += drv_data->tx_map_len; |
5928808e | 136 | drv_data->rx += drv_data->rx_map_len; |
5928808e MW |
137 | |
138 | msg->actual_length += drv_data->len; | |
139 | msg->state = pxa2xx_spi_next_transfer(drv_data); | |
140 | } else { | |
141 | /* In case we got an error we disable the SSP now */ | |
142 | write_SSCR0(read_SSCR0(reg) & ~SSCR0_SSE, reg); | |
143 | ||
144 | msg->state = ERROR_STATE; | |
145 | } | |
146 | ||
147 | tasklet_schedule(&drv_data->pump_transfers); | |
148 | } | |
149 | } | |
150 | ||
151 | static void pxa2xx_spi_dma_callback(void *data) | |
152 | { | |
153 | pxa2xx_spi_dma_transfer_complete(data, false); | |
154 | } | |
155 | ||
156 | static struct dma_async_tx_descriptor * | |
157 | pxa2xx_spi_dma_prepare_one(struct driver_data *drv_data, | |
158 | enum dma_transfer_direction dir) | |
159 | { | |
160 | struct pxa2xx_spi_master *pdata = drv_data->master_info; | |
161 | struct chip_data *chip = drv_data->cur_chip; | |
162 | enum dma_slave_buswidth width; | |
163 | struct dma_slave_config cfg; | |
164 | struct dma_chan *chan; | |
165 | struct sg_table *sgt; | |
166 | int nents, ret; | |
167 | ||
168 | switch (drv_data->n_bytes) { | |
169 | case 1: | |
170 | width = DMA_SLAVE_BUSWIDTH_1_BYTE; | |
171 | break; | |
172 | case 2: | |
173 | width = DMA_SLAVE_BUSWIDTH_2_BYTES; | |
174 | break; | |
175 | default: | |
176 | width = DMA_SLAVE_BUSWIDTH_4_BYTES; | |
177 | break; | |
178 | } | |
179 | ||
180 | memset(&cfg, 0, sizeof(cfg)); | |
181 | cfg.direction = dir; | |
182 | ||
183 | if (dir == DMA_MEM_TO_DEV) { | |
184 | cfg.dst_addr = drv_data->ssdr_physical; | |
185 | cfg.dst_addr_width = width; | |
186 | cfg.dst_maxburst = chip->dma_burst_size; | |
187 | cfg.slave_id = pdata->tx_slave_id; | |
188 | ||
189 | sgt = &drv_data->tx_sgt; | |
190 | nents = drv_data->tx_nents; | |
191 | chan = drv_data->tx_chan; | |
192 | } else { | |
193 | cfg.src_addr = drv_data->ssdr_physical; | |
194 | cfg.src_addr_width = width; | |
195 | cfg.src_maxburst = chip->dma_burst_size; | |
196 | cfg.slave_id = pdata->rx_slave_id; | |
197 | ||
198 | sgt = &drv_data->rx_sgt; | |
199 | nents = drv_data->rx_nents; | |
200 | chan = drv_data->rx_chan; | |
201 | } | |
202 | ||
203 | ret = dmaengine_slave_config(chan, &cfg); | |
204 | if (ret) { | |
205 | dev_warn(&drv_data->pdev->dev, "DMA slave config failed\n"); | |
206 | return NULL; | |
207 | } | |
208 | ||
209 | return dmaengine_prep_slave_sg(chan, sgt->sgl, nents, dir, | |
210 | DMA_PREP_INTERRUPT | DMA_CTRL_ACK); | |
211 | } | |
212 | ||
213 | static bool pxa2xx_spi_dma_filter(struct dma_chan *chan, void *param) | |
214 | { | |
215 | const struct pxa2xx_spi_master *pdata = param; | |
216 | ||
217 | return chan->chan_id == pdata->tx_chan_id || | |
218 | chan->chan_id == pdata->rx_chan_id; | |
219 | } | |
220 | ||
221 | bool pxa2xx_spi_dma_is_possible(size_t len) | |
222 | { | |
223 | return len <= MAX_DMA_LEN; | |
224 | } | |
225 | ||
226 | int pxa2xx_spi_map_dma_buffers(struct driver_data *drv_data) | |
227 | { | |
228 | const struct chip_data *chip = drv_data->cur_chip; | |
229 | int ret; | |
230 | ||
231 | if (!chip->enable_dma) | |
232 | return 0; | |
233 | ||
234 | /* Don't bother with DMA if we can't do even a single burst */ | |
235 | if (drv_data->len < chip->dma_burst_size) | |
236 | return 0; | |
237 | ||
238 | ret = pxa2xx_spi_map_dma_buffer(drv_data, DMA_TO_DEVICE); | |
239 | if (ret <= 0) { | |
240 | dev_warn(&drv_data->pdev->dev, "failed to DMA map TX\n"); | |
241 | return 0; | |
242 | } | |
243 | ||
244 | drv_data->tx_nents = ret; | |
245 | ||
246 | ret = pxa2xx_spi_map_dma_buffer(drv_data, DMA_FROM_DEVICE); | |
247 | if (ret <= 0) { | |
248 | pxa2xx_spi_unmap_dma_buffer(drv_data, DMA_TO_DEVICE); | |
249 | dev_warn(&drv_data->pdev->dev, "failed to DMA map RX\n"); | |
250 | return 0; | |
251 | } | |
252 | ||
253 | drv_data->rx_nents = ret; | |
254 | return 1; | |
255 | } | |
256 | ||
257 | irqreturn_t pxa2xx_spi_dma_transfer(struct driver_data *drv_data) | |
258 | { | |
259 | u32 status; | |
260 | ||
261 | status = read_SSSR(drv_data->ioaddr) & drv_data->mask_sr; | |
262 | if (status & SSSR_ROR) { | |
263 | dev_err(&drv_data->pdev->dev, "FIFO overrun\n"); | |
264 | ||
265 | dmaengine_terminate_all(drv_data->rx_chan); | |
266 | dmaengine_terminate_all(drv_data->tx_chan); | |
267 | ||
268 | pxa2xx_spi_dma_transfer_complete(drv_data, true); | |
269 | return IRQ_HANDLED; | |
270 | } | |
271 | ||
272 | return IRQ_NONE; | |
273 | } | |
274 | ||
275 | int pxa2xx_spi_dma_prepare(struct driver_data *drv_data, u32 dma_burst) | |
276 | { | |
277 | struct dma_async_tx_descriptor *tx_desc, *rx_desc; | |
278 | ||
279 | tx_desc = pxa2xx_spi_dma_prepare_one(drv_data, DMA_MEM_TO_DEV); | |
280 | if (!tx_desc) { | |
281 | dev_err(&drv_data->pdev->dev, | |
282 | "failed to get DMA TX descriptor\n"); | |
283 | return -EBUSY; | |
284 | } | |
285 | ||
286 | rx_desc = pxa2xx_spi_dma_prepare_one(drv_data, DMA_DEV_TO_MEM); | |
287 | if (!rx_desc) { | |
288 | dev_err(&drv_data->pdev->dev, | |
289 | "failed to get DMA RX descriptor\n"); | |
290 | return -EBUSY; | |
291 | } | |
292 | ||
293 | /* We are ready when RX completes */ | |
294 | rx_desc->callback = pxa2xx_spi_dma_callback; | |
295 | rx_desc->callback_param = drv_data; | |
296 | ||
297 | dmaengine_submit(rx_desc); | |
298 | dmaengine_submit(tx_desc); | |
299 | return 0; | |
300 | } | |
301 | ||
302 | void pxa2xx_spi_dma_start(struct driver_data *drv_data) | |
303 | { | |
304 | dma_async_issue_pending(drv_data->rx_chan); | |
305 | dma_async_issue_pending(drv_data->tx_chan); | |
306 | ||
307 | atomic_set(&drv_data->dma_running, 1); | |
308 | } | |
309 | ||
310 | int pxa2xx_spi_dma_setup(struct driver_data *drv_data) | |
311 | { | |
312 | struct pxa2xx_spi_master *pdata = drv_data->master_info; | |
cddb339b | 313 | struct device *dev = &drv_data->pdev->dev; |
5928808e MW |
314 | dma_cap_mask_t mask; |
315 | ||
316 | dma_cap_zero(mask); | |
317 | dma_cap_set(DMA_SLAVE, mask); | |
318 | ||
cddb339b | 319 | drv_data->dummy = devm_kzalloc(dev, SZ_2K, GFP_KERNEL); |
5928808e MW |
320 | if (!drv_data->dummy) |
321 | return -ENOMEM; | |
322 | ||
cddb339b MW |
323 | drv_data->tx_chan = dma_request_slave_channel_compat(mask, |
324 | pxa2xx_spi_dma_filter, pdata, dev, "tx"); | |
5928808e MW |
325 | if (!drv_data->tx_chan) |
326 | return -ENODEV; | |
327 | ||
cddb339b MW |
328 | drv_data->rx_chan = dma_request_slave_channel_compat(mask, |
329 | pxa2xx_spi_dma_filter, pdata, dev, "rx"); | |
5928808e MW |
330 | if (!drv_data->rx_chan) { |
331 | dma_release_channel(drv_data->tx_chan); | |
332 | drv_data->tx_chan = NULL; | |
333 | return -ENODEV; | |
334 | } | |
335 | ||
336 | return 0; | |
337 | } | |
338 | ||
339 | void pxa2xx_spi_dma_release(struct driver_data *drv_data) | |
340 | { | |
341 | if (drv_data->rx_chan) { | |
342 | dmaengine_terminate_all(drv_data->rx_chan); | |
343 | dma_release_channel(drv_data->rx_chan); | |
344 | sg_free_table(&drv_data->rx_sgt); | |
345 | drv_data->rx_chan = NULL; | |
346 | } | |
347 | if (drv_data->tx_chan) { | |
348 | dmaengine_terminate_all(drv_data->tx_chan); | |
349 | dma_release_channel(drv_data->tx_chan); | |
350 | sg_free_table(&drv_data->tx_sgt); | |
351 | drv_data->tx_chan = NULL; | |
352 | } | |
353 | } | |
354 | ||
355 | void pxa2xx_spi_dma_resume(struct driver_data *drv_data) | |
356 | { | |
357 | } | |
358 | ||
359 | int pxa2xx_spi_set_dma_burst_and_threshold(struct chip_data *chip, | |
360 | struct spi_device *spi, | |
361 | u8 bits_per_word, u32 *burst_code, | |
362 | u32 *threshold) | |
363 | { | |
364 | struct pxa2xx_spi_chip *chip_info = spi->controller_data; | |
365 | ||
366 | /* | |
367 | * If the DMA burst size is given in chip_info we use that, | |
368 | * otherwise we use the default. Also we use the default FIFO | |
369 | * thresholds for now. | |
370 | */ | |
01d7aafb | 371 | *burst_code = chip_info ? chip_info->dma_burst_size : 1; |
5928808e MW |
372 | *threshold = SSCR1_RxTresh(RX_THRESH_DFLT) |
373 | | SSCR1_TxTresh(TX_THRESH_DFLT); | |
374 | ||
375 | return 0; | |
376 | } |