1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2003-2015 Broadcom Corporation
4 * All Rights Reserved
5 */
6 #include <linux/acpi.h>
7 #include <linux/clk.h>
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/platform_device.h>
11 #include <linux/spi/spi.h>
12 #include <linux/of.h>
13 #include <linux/interrupt.h>
14
15 /* SPI Configuration Register */
16 #define XLP_SPI_CONFIG 0x00
17 #define XLP_SPI_CPHA BIT(0)
18 #define XLP_SPI_CPOL BIT(1)
19 #define XLP_SPI_CS_POL BIT(2)
20 #define XLP_SPI_TXMISO_EN BIT(3)
21 #define XLP_SPI_TXMOSI_EN BIT(4)
22 #define XLP_SPI_RXMISO_EN BIT(5)
23 #define XLP_SPI_CS_LSBFE BIT(10)
24 #define XLP_SPI_RXCAP_EN BIT(11)
25
26 /* SPI Frequency Divider Register */
27 #define XLP_SPI_FDIV 0x04
28
29 /* SPI Command Register */
30 #define XLP_SPI_CMD 0x08
31 #define XLP_SPI_CMD_IDLE_MASK 0x0
32 #define XLP_SPI_CMD_TX_MASK 0x1
33 #define XLP_SPI_CMD_RX_MASK 0x2
34 #define XLP_SPI_CMD_TXRX_MASK 0x3
35 #define XLP_SPI_CMD_CONT BIT(4)
36 #define XLP_SPI_XFR_BITCNT_SHIFT 16
37
38 /* SPI Status Register */
39 #define XLP_SPI_STATUS 0x0c
40 #define XLP_SPI_XFR_PENDING BIT(0)
41 #define XLP_SPI_XFR_DONE BIT(1)
42 #define XLP_SPI_TX_INT BIT(2)
43 #define XLP_SPI_RX_INT BIT(3)
44 #define XLP_SPI_TX_UF BIT(4)
45 #define XLP_SPI_RX_OF BIT(5)
46 #define XLP_SPI_STAT_MASK 0x3f
47
48 /* SPI Interrupt Enable Register */
49 #define XLP_SPI_INTR_EN 0x10
50 #define XLP_SPI_INTR_DONE BIT(0)
51 #define XLP_SPI_INTR_TXTH BIT(1)
52 #define XLP_SPI_INTR_RXTH BIT(2)
53 #define XLP_SPI_INTR_TXUF BIT(3)
54 #define XLP_SPI_INTR_RXOF BIT(4)
55
56 /* SPI FIFO Threshold Register */
57 #define XLP_SPI_FIFO_THRESH 0x14
58
59 /* SPI FIFO Word Count Register */
60 #define XLP_SPI_FIFO_WCNT 0x18
61 #define XLP_SPI_RXFIFO_WCNT_MASK 0xf
62 #define XLP_SPI_TXFIFO_WCNT_MASK 0xf0
63 #define XLP_SPI_TXFIFO_WCNT_SHIFT 4
64
65 /* SPI Transmit Data FIFO Register */
66 #define XLP_SPI_TXDATA_FIFO 0x1c
67
68 /* SPI Receive Data FIFO Register */
69 #define XLP_SPI_RXDATA_FIFO 0x20
70
71 /* SPI System Control Register */
72 #define XLP_SPI_SYSCTRL 0x100
73 #define XLP_SPI_SYS_RESET BIT(0)
74 #define XLP_SPI_SYS_CLKDIS BIT(1)
75 #define XLP_SPI_SYS_PMEN BIT(8)
76
77 #define SPI_CS_OFFSET 0x40
78 #define XLP_SPI_TXRXTH 0x80
79 #define XLP_SPI_FIFO_SIZE 8
80 #define XLP_SPI_MAX_CS 4
81 #define XLP_SPI_DEFAULT_FREQ 133333333
82 #define XLP_SPI_FDIV_MIN 4
83 #define XLP_SPI_FDIV_MAX 65535
84 /*
85 * SPI can transfer only 28 bytes properly at a time. So split the
86 * transfer into 28 bytes size.
87 */
88 #define XLP_SPI_XFER_SIZE 28
89
90 struct xlp_spi_priv {
91 struct device dev; /* device structure */
92 void __iomem *base; /* spi registers base address */
93 const u8 *tx_buf; /* tx data buffer */
94 u8 *rx_buf; /* rx data buffer */
95 int tx_len; /* tx xfer length */
96 int rx_len; /* rx xfer length */
97 int txerrors; /* TXFIFO underflow count */
98 int rxerrors; /* RXFIFO overflow count */
99 int cs; /* slave device chip select */
100 u32 spi_clk; /* spi clock frequency */
101 bool cmd_cont; /* cs active */
102 struct completion done; /* completion notification */
103 };
104
xlp_spi_reg_read(struct xlp_spi_priv * priv,int cs,int regoff)105 static inline u32 xlp_spi_reg_read(struct xlp_spi_priv *priv,
106 int cs, int regoff)
107 {
108 return readl(priv->base + regoff + cs * SPI_CS_OFFSET);
109 }
110
xlp_spi_reg_write(struct xlp_spi_priv * priv,int cs,int regoff,u32 val)111 static inline void xlp_spi_reg_write(struct xlp_spi_priv *priv, int cs,
112 int regoff, u32 val)
113 {
114 writel(val, priv->base + regoff + cs * SPI_CS_OFFSET);
115 }
116
xlp_spi_sysctl_write(struct xlp_spi_priv * priv,int regoff,u32 val)117 static inline void xlp_spi_sysctl_write(struct xlp_spi_priv *priv,
118 int regoff, u32 val)
119 {
120 writel(val, priv->base + regoff);
121 }
122
123 /*
124 * Setup global SPI_SYSCTRL register for all SPI channels.
125 */
xlp_spi_sysctl_setup(struct xlp_spi_priv * xspi)126 static void xlp_spi_sysctl_setup(struct xlp_spi_priv *xspi)
127 {
128 int cs;
129
130 for (cs = 0; cs < XLP_SPI_MAX_CS; cs++)
131 xlp_spi_sysctl_write(xspi, XLP_SPI_SYSCTRL,
132 XLP_SPI_SYS_RESET << cs);
133 xlp_spi_sysctl_write(xspi, XLP_SPI_SYSCTRL, XLP_SPI_SYS_PMEN);
134 }
135
xlp_spi_setup(struct spi_device * spi)136 static int xlp_spi_setup(struct spi_device *spi)
137 {
138 struct xlp_spi_priv *xspi;
139 u32 fdiv, cfg;
140 int cs;
141
142 xspi = spi_master_get_devdata(spi->master);
143 cs = spi->chip_select;
144 /*
145 * The value of fdiv must be between 4 and 65535.
146 */
147 fdiv = DIV_ROUND_UP(xspi->spi_clk, spi->max_speed_hz);
148 if (fdiv > XLP_SPI_FDIV_MAX)
149 fdiv = XLP_SPI_FDIV_MAX;
150 else if (fdiv < XLP_SPI_FDIV_MIN)
151 fdiv = XLP_SPI_FDIV_MIN;
152
153 xlp_spi_reg_write(xspi, cs, XLP_SPI_FDIV, fdiv);
154 xlp_spi_reg_write(xspi, cs, XLP_SPI_FIFO_THRESH, XLP_SPI_TXRXTH);
155 cfg = xlp_spi_reg_read(xspi, cs, XLP_SPI_CONFIG);
156 if (spi->mode & SPI_CPHA)
157 cfg |= XLP_SPI_CPHA;
158 else
159 cfg &= ~XLP_SPI_CPHA;
160 if (spi->mode & SPI_CPOL)
161 cfg |= XLP_SPI_CPOL;
162 else
163 cfg &= ~XLP_SPI_CPOL;
164 if (!(spi->mode & SPI_CS_HIGH))
165 cfg |= XLP_SPI_CS_POL;
166 else
167 cfg &= ~XLP_SPI_CS_POL;
168 if (spi->mode & SPI_LSB_FIRST)
169 cfg |= XLP_SPI_CS_LSBFE;
170 else
171 cfg &= ~XLP_SPI_CS_LSBFE;
172
173 cfg |= XLP_SPI_TXMOSI_EN | XLP_SPI_RXMISO_EN;
174 if (fdiv == 4)
175 cfg |= XLP_SPI_RXCAP_EN;
176 xlp_spi_reg_write(xspi, cs, XLP_SPI_CONFIG, cfg);
177
178 return 0;
179 }
180
xlp_spi_read_rxfifo(struct xlp_spi_priv * xspi)181 static void xlp_spi_read_rxfifo(struct xlp_spi_priv *xspi)
182 {
183 u32 rx_data, rxfifo_cnt;
184 int i, j, nbytes;
185
186 rxfifo_cnt = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_FIFO_WCNT);
187 rxfifo_cnt &= XLP_SPI_RXFIFO_WCNT_MASK;
188 while (rxfifo_cnt) {
189 rx_data = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_RXDATA_FIFO);
190 j = 0;
191 nbytes = min(xspi->rx_len, 4);
192 for (i = nbytes - 1; i >= 0; i--, j++)
193 xspi->rx_buf[i] = (rx_data >> (j * 8)) & 0xff;
194
195 xspi->rx_len -= nbytes;
196 xspi->rx_buf += nbytes;
197 rxfifo_cnt--;
198 }
199 }
200
xlp_spi_fill_txfifo(struct xlp_spi_priv * xspi)201 static void xlp_spi_fill_txfifo(struct xlp_spi_priv *xspi)
202 {
203 u32 tx_data, txfifo_cnt;
204 int i, j, nbytes;
205
206 txfifo_cnt = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_FIFO_WCNT);
207 txfifo_cnt &= XLP_SPI_TXFIFO_WCNT_MASK;
208 txfifo_cnt >>= XLP_SPI_TXFIFO_WCNT_SHIFT;
209 while (xspi->tx_len && (txfifo_cnt < XLP_SPI_FIFO_SIZE)) {
210 j = 0;
211 tx_data = 0;
212 nbytes = min(xspi->tx_len, 4);
213 for (i = nbytes - 1; i >= 0; i--, j++)
214 tx_data |= xspi->tx_buf[i] << (j * 8);
215
216 xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_TXDATA_FIFO, tx_data);
217 xspi->tx_len -= nbytes;
218 xspi->tx_buf += nbytes;
219 txfifo_cnt++;
220 }
221 }
222
xlp_spi_interrupt(int irq,void * dev_id)223 static irqreturn_t xlp_spi_interrupt(int irq, void *dev_id)
224 {
225 struct xlp_spi_priv *xspi = dev_id;
226 u32 stat;
227
228 stat = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_STATUS) &
229 XLP_SPI_STAT_MASK;
230 if (!stat)
231 return IRQ_NONE;
232
233 if (stat & XLP_SPI_TX_INT) {
234 if (xspi->tx_len)
235 xlp_spi_fill_txfifo(xspi);
236 if (stat & XLP_SPI_TX_UF)
237 xspi->txerrors++;
238 }
239
240 if (stat & XLP_SPI_RX_INT) {
241 if (xspi->rx_len)
242 xlp_spi_read_rxfifo(xspi);
243 if (stat & XLP_SPI_RX_OF)
244 xspi->rxerrors++;
245 }
246
247 /* write status back to clear interrupts */
248 xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_STATUS, stat);
249 if (stat & XLP_SPI_XFR_DONE)
250 complete(&xspi->done);
251
252 return IRQ_HANDLED;
253 }
254
xlp_spi_send_cmd(struct xlp_spi_priv * xspi,int xfer_len,int cmd_cont)255 static void xlp_spi_send_cmd(struct xlp_spi_priv *xspi, int xfer_len,
256 int cmd_cont)
257 {
258 u32 cmd = 0;
259
260 if (xspi->tx_buf)
261 cmd |= XLP_SPI_CMD_TX_MASK;
262 if (xspi->rx_buf)
263 cmd |= XLP_SPI_CMD_RX_MASK;
264 if (cmd_cont)
265 cmd |= XLP_SPI_CMD_CONT;
266 cmd |= ((xfer_len * 8 - 1) << XLP_SPI_XFR_BITCNT_SHIFT);
267 xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_CMD, cmd);
268 }
269
xlp_spi_xfer_block(struct xlp_spi_priv * xs,const unsigned char * tx_buf,unsigned char * rx_buf,int xfer_len,int cmd_cont)270 static int xlp_spi_xfer_block(struct xlp_spi_priv *xs,
271 const unsigned char *tx_buf,
272 unsigned char *rx_buf, int xfer_len, int cmd_cont)
273 {
274 int timeout;
275 u32 intr_mask = 0;
276
277 xs->tx_buf = tx_buf;
278 xs->rx_buf = rx_buf;
279 xs->tx_len = (xs->tx_buf == NULL) ? 0 : xfer_len;
280 xs->rx_len = (xs->rx_buf == NULL) ? 0 : xfer_len;
281 xs->txerrors = xs->rxerrors = 0;
282
283 /* fill TXDATA_FIFO, then send the CMD */
284 if (xs->tx_len)
285 xlp_spi_fill_txfifo(xs);
286
287 xlp_spi_send_cmd(xs, xfer_len, cmd_cont);
288
289 /*
290 * We are getting some spurious tx interrupts, so avoid enabling
291 * tx interrupts when only rx is in process.
292 * Enable all the interrupts in tx case.
293 */
294 if (xs->tx_len)
295 intr_mask |= XLP_SPI_INTR_TXTH | XLP_SPI_INTR_TXUF |
296 XLP_SPI_INTR_RXTH | XLP_SPI_INTR_RXOF;
297 else
298 intr_mask |= XLP_SPI_INTR_RXTH | XLP_SPI_INTR_RXOF;
299
300 intr_mask |= XLP_SPI_INTR_DONE;
301 xlp_spi_reg_write(xs, xs->cs, XLP_SPI_INTR_EN, intr_mask);
302
303 timeout = wait_for_completion_timeout(&xs->done,
304 msecs_to_jiffies(1000));
305 /* Disable interrupts */
306 xlp_spi_reg_write(xs, xs->cs, XLP_SPI_INTR_EN, 0x0);
307 if (!timeout) {
308 dev_err(&xs->dev, "xfer timedout!\n");
309 goto out;
310 }
311 if (xs->txerrors || xs->rxerrors)
312 dev_err(&xs->dev, "Over/Underflow rx %d tx %d xfer %d!\n",
313 xs->rxerrors, xs->txerrors, xfer_len);
314
315 return xfer_len;
316 out:
317 return -ETIMEDOUT;
318 }
319
xlp_spi_txrx_bufs(struct xlp_spi_priv * xs,struct spi_transfer * t)320 static int xlp_spi_txrx_bufs(struct xlp_spi_priv *xs, struct spi_transfer *t)
321 {
322 int bytesleft, sz;
323 unsigned char *rx_buf;
324 const unsigned char *tx_buf;
325
326 tx_buf = t->tx_buf;
327 rx_buf = t->rx_buf;
328 bytesleft = t->len;
329 while (bytesleft) {
330 if (bytesleft > XLP_SPI_XFER_SIZE)
331 sz = xlp_spi_xfer_block(xs, tx_buf, rx_buf,
332 XLP_SPI_XFER_SIZE, 1);
333 else
334 sz = xlp_spi_xfer_block(xs, tx_buf, rx_buf,
335 bytesleft, xs->cmd_cont);
336 if (sz < 0)
337 return sz;
338 bytesleft -= sz;
339 if (tx_buf)
340 tx_buf += sz;
341 if (rx_buf)
342 rx_buf += sz;
343 }
344 return bytesleft;
345 }
346
xlp_spi_transfer_one(struct spi_master * master,struct spi_device * spi,struct spi_transfer * t)347 static int xlp_spi_transfer_one(struct spi_master *master,
348 struct spi_device *spi,
349 struct spi_transfer *t)
350 {
351 struct xlp_spi_priv *xspi = spi_master_get_devdata(master);
352 int ret = 0;
353
354 xspi->cs = spi->chip_select;
355 xspi->dev = spi->dev;
356
357 if (spi_transfer_is_last(master, t))
358 xspi->cmd_cont = 0;
359 else
360 xspi->cmd_cont = 1;
361
362 if (xlp_spi_txrx_bufs(xspi, t))
363 ret = -EIO;
364
365 spi_finalize_current_transfer(master);
366 return ret;
367 }
368
xlp_spi_probe(struct platform_device * pdev)369 static int xlp_spi_probe(struct platform_device *pdev)
370 {
371 struct spi_master *master;
372 struct xlp_spi_priv *xspi;
373 struct clk *clk;
374 int irq, err;
375
376 xspi = devm_kzalloc(&pdev->dev, sizeof(*xspi), GFP_KERNEL);
377 if (!xspi)
378 return -ENOMEM;
379
380 xspi->base = devm_platform_ioremap_resource(pdev, 0);
381 if (IS_ERR(xspi->base))
382 return PTR_ERR(xspi->base);
383
384 irq = platform_get_irq(pdev, 0);
385 if (irq < 0)
386 return irq;
387 err = devm_request_irq(&pdev->dev, irq, xlp_spi_interrupt, 0,
388 pdev->name, xspi);
389 if (err) {
390 dev_err(&pdev->dev, "unable to request irq %d\n", irq);
391 return err;
392 }
393
394 clk = devm_clk_get(&pdev->dev, NULL);
395 if (IS_ERR(clk)) {
396 dev_err(&pdev->dev, "could not get spi clock\n");
397 return PTR_ERR(clk);
398 }
399
400 xspi->spi_clk = clk_get_rate(clk);
401
402 master = spi_alloc_master(&pdev->dev, 0);
403 if (!master) {
404 dev_err(&pdev->dev, "could not alloc master\n");
405 return -ENOMEM;
406 }
407
408 master->bus_num = 0;
409 master->num_chipselect = XLP_SPI_MAX_CS;
410 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
411 master->setup = xlp_spi_setup;
412 master->transfer_one = xlp_spi_transfer_one;
413 master->dev.of_node = pdev->dev.of_node;
414
415 init_completion(&xspi->done);
416 spi_master_set_devdata(master, xspi);
417 xlp_spi_sysctl_setup(xspi);
418
419 /* register spi controller */
420 err = devm_spi_register_master(&pdev->dev, master);
421 if (err) {
422 dev_err(&pdev->dev, "spi register master failed!\n");
423 spi_master_put(master);
424 return err;
425 }
426
427 return 0;
428 }
429
430 #ifdef CONFIG_ACPI
431 static const struct acpi_device_id xlp_spi_acpi_match[] = {
432 { "BRCM900D", 0 },
433 { "CAV900D", 0 },
434 { },
435 };
436 MODULE_DEVICE_TABLE(acpi, xlp_spi_acpi_match);
437 #endif
438
439 static const struct of_device_id xlp_spi_dt_id[] = {
440 { .compatible = "netlogic,xlp832-spi" },
441 { },
442 };
443 MODULE_DEVICE_TABLE(of, xlp_spi_dt_id);
444
445 static struct platform_driver xlp_spi_driver = {
446 .probe = xlp_spi_probe,
447 .driver = {
448 .name = "xlp-spi",
449 .of_match_table = xlp_spi_dt_id,
450 .acpi_match_table = ACPI_PTR(xlp_spi_acpi_match),
451 },
452 };
453 module_platform_driver(xlp_spi_driver);
454
455 MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
456 MODULE_DESCRIPTION("Netlogic XLP SPI controller driver");
457 MODULE_LICENSE("GPL v2");
458