1/*
2 * Platform CAN bus driver for Bosch C_CAN controller
3 *
4 * Copyright (C) 2010 ST Microelectronics
5 * Bhupesh Sharma <bhupesh.sharma@st.com>
6 *
7 * Borrowed heavily from the C_CAN driver originally written by:
8 * Copyright (C) 2007
9 * - Sascha Hauer, Marc Kleine-Budde, Pengutronix <s.hauer@pengutronix.de>
10 * - Simon Kallweit, intefo AG <simon.kallweit@intefo.ch>
11 *
12 * Bosch C_CAN controller is compliant to CAN protocol version 2.0 part A and B.
13 * Bosch C_CAN user manual can be obtained from:
14 * http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/c_can/
15 * users_manual_c_can.pdf
16 *
17 * This file is licensed under the terms of the GNU General Public
18 * License version 2. This program is licensed "as is" without any
19 * warranty of any kind, whether express or implied.
20 */
21
22#include <linux/kernel.h>
23#include <linux/module.h>
24#include <linux/interrupt.h>
25#include <linux/delay.h>
26#include <linux/netdevice.h>
27#include <linux/if_arp.h>
28#include <linux/if_ether.h>
29#include <linux/list.h>
30#include <linux/io.h>
31#include <linux/platform_device.h>
32#include <linux/pm_runtime.h>
33#include <linux/property.h>
34#include <linux/clk.h>
35#include <linux/of.h>
36#include <linux/mfd/syscon.h>
37#include <linux/regmap.h>
38
39#include <linux/can/dev.h>
40
41#include "c_can.h"
42
43#define DCAN_RAM_INIT_BIT BIT(3)
44
45static DEFINE_SPINLOCK(raminit_lock);
46
47/* 16-bit c_can registers can be arranged differently in the memory
48 * architecture of different implementations. For example: 16-bit
49 * registers can be aligned to a 16-bit boundary or 32-bit boundary etc.
50 * Handle the same by providing a common read/write interface.
51 */
52static u16 c_can_plat_read_reg_aligned_to_16bit(const struct c_can_priv *priv,
53 enum reg index)
54{
55 return readw(addr: priv->base + priv->regs[index]);
56}
57
58static void c_can_plat_write_reg_aligned_to_16bit(const struct c_can_priv *priv,
59 enum reg index, u16 val)
60{
61 writew(val, addr: priv->base + priv->regs[index]);
62}
63
64static u16 c_can_plat_read_reg_aligned_to_32bit(const struct c_can_priv *priv,
65 enum reg index)
66{
67 return readw(addr: priv->base + 2 * priv->regs[index]);
68}
69
70static void c_can_plat_write_reg_aligned_to_32bit(const struct c_can_priv *priv,
71 enum reg index, u16 val)
72{
73 writew(val, addr: priv->base + 2 * priv->regs[index]);
74}
75
76static void c_can_hw_raminit_wait_syscon(const struct c_can_priv *priv,
77 u32 mask, u32 val)
78{
79 const struct c_can_raminit *raminit = &priv->raminit_sys;
80 int timeout = 0;
81 u32 ctrl = 0;
82
83 /* We look only at the bits of our instance. */
84 val &= mask;
85 do {
86 udelay(1);
87 timeout++;
88
89 regmap_read(map: raminit->syscon, reg: raminit->reg, val: &ctrl);
90 if (timeout == 1000) {
91 dev_err(&priv->dev->dev, "%s: time out\n", __func__);
92 break;
93 }
94 } while ((ctrl & mask) != val);
95}
96
97static void c_can_hw_raminit_syscon(const struct c_can_priv *priv, bool enable)
98{
99 const struct c_can_raminit *raminit = &priv->raminit_sys;
100 u32 ctrl = 0;
101 u32 mask;
102
103 spin_lock(lock: &raminit_lock);
104
105 mask = 1 << raminit->bits.start | 1 << raminit->bits.done;
106 regmap_read(map: raminit->syscon, reg: raminit->reg, val: &ctrl);
107
108 /* We clear the start bit first. The start bit is
109 * looking at the 0 -> transition, but is not self clearing;
110 * NOTE: DONE must be written with 1 to clear it.
111 * We can't clear the DONE bit here using regmap_update_bits()
112 * as it will bypass the write if initial condition is START:0 DONE:1
113 * e.g. on DRA7 which needs START pulse.
114 */
115 ctrl &= ~mask; /* START = 0, DONE = 0 */
116 regmap_update_bits(map: raminit->syscon, reg: raminit->reg, mask, val: ctrl);
117
118 /* check if START bit is 0. Ignore DONE bit for now
119 * as it can be either 0 or 1.
120 */
121 c_can_hw_raminit_wait_syscon(priv, mask: 1 << raminit->bits.start, val: ctrl);
122
123 if (enable) {
124 /* Clear DONE bit & set START bit. */
125 ctrl |= 1 << raminit->bits.start;
126 /* DONE must be written with 1 to clear it */
127 ctrl |= 1 << raminit->bits.done;
128 regmap_update_bits(map: raminit->syscon, reg: raminit->reg, mask, val: ctrl);
129 /* prevent further clearing of DONE bit */
130 ctrl &= ~(1 << raminit->bits.done);
131 /* clear START bit if start pulse is needed */
132 if (raminit->needs_pulse) {
133 ctrl &= ~(1 << raminit->bits.start);
134 regmap_update_bits(map: raminit->syscon, reg: raminit->reg,
135 mask, val: ctrl);
136 }
137
138 ctrl |= 1 << raminit->bits.done;
139 c_can_hw_raminit_wait_syscon(priv, mask, val: ctrl);
140 }
141 spin_unlock(lock: &raminit_lock);
142}
143
144static u32 c_can_plat_read_reg32(const struct c_can_priv *priv, enum reg index)
145{
146 u32 val;
147
148 val = priv->read_reg(priv, index);
149 val |= ((u32)priv->read_reg(priv, index + 1)) << 16;
150
151 return val;
152}
153
154static void c_can_plat_write_reg32(const struct c_can_priv *priv,
155 enum reg index, u32 val)
156{
157 priv->write_reg(priv, index + 1, val >> 16);
158 priv->write_reg(priv, index, val);
159}
160
161static u32 d_can_plat_read_reg32(const struct c_can_priv *priv, enum reg index)
162{
163 return readl(addr: priv->base + priv->regs[index]);
164}
165
166static void d_can_plat_write_reg32(const struct c_can_priv *priv,
167 enum reg index, u32 val)
168{
169 writel(val, addr: priv->base + priv->regs[index]);
170}
171
172static void c_can_hw_raminit_wait(const struct c_can_priv *priv, u32 mask)
173{
174 while (priv->read_reg32(priv, C_CAN_FUNCTION_REG) & mask)
175 udelay(1);
176}
177
178static void c_can_hw_raminit(const struct c_can_priv *priv, bool enable)
179{
180 u32 ctrl;
181
182 ctrl = priv->read_reg32(priv, C_CAN_FUNCTION_REG);
183 ctrl &= ~DCAN_RAM_INIT_BIT;
184 priv->write_reg32(priv, C_CAN_FUNCTION_REG, ctrl);
185 c_can_hw_raminit_wait(priv, mask: ctrl);
186
187 if (enable) {
188 ctrl |= DCAN_RAM_INIT_BIT;
189 priv->write_reg32(priv, C_CAN_FUNCTION_REG, ctrl);
190 c_can_hw_raminit_wait(priv, mask: ctrl);
191 }
192}
193
194static const struct c_can_driver_data c_can_drvdata = {
195 .id = BOSCH_C_CAN,
196 .msg_obj_num = 32,
197};
198
199static const struct c_can_driver_data d_can_drvdata = {
200 .id = BOSCH_D_CAN,
201 .msg_obj_num = 32,
202};
203
204static const struct raminit_bits dra7_raminit_bits[] = {
205 [0] = { .start = 3, .done = 1, },
206 [1] = { .start = 5, .done = 2, },
207};
208
209static const struct c_can_driver_data dra7_dcan_drvdata = {
210 .id = BOSCH_D_CAN,
211 .msg_obj_num = 64,
212 .raminit_num = ARRAY_SIZE(dra7_raminit_bits),
213 .raminit_bits = dra7_raminit_bits,
214 .raminit_pulse = true,
215};
216
217static const struct raminit_bits am3352_raminit_bits[] = {
218 [0] = { .start = 0, .done = 8, },
219 [1] = { .start = 1, .done = 9, },
220};
221
222static const struct c_can_driver_data am3352_dcan_drvdata = {
223 .id = BOSCH_D_CAN,
224 .msg_obj_num = 64,
225 .raminit_num = ARRAY_SIZE(am3352_raminit_bits),
226 .raminit_bits = am3352_raminit_bits,
227};
228
229static const struct platform_device_id c_can_id_table[] = {
230 {
231 .name = KBUILD_MODNAME,
232 .driver_data = (kernel_ulong_t)&c_can_drvdata,
233 },
234 {
235 .name = "c_can",
236 .driver_data = (kernel_ulong_t)&c_can_drvdata,
237 },
238 {
239 .name = "d_can",
240 .driver_data = (kernel_ulong_t)&d_can_drvdata,
241 },
242 { /* sentinel */ },
243};
244MODULE_DEVICE_TABLE(platform, c_can_id_table);
245
246static const struct of_device_id c_can_of_table[] = {
247 { .compatible = "bosch,c_can", .data = &c_can_drvdata },
248 { .compatible = "bosch,d_can", .data = &d_can_drvdata },
249 { .compatible = "ti,dra7-d_can", .data = &dra7_dcan_drvdata },
250 { .compatible = "ti,am3352-d_can", .data = &am3352_dcan_drvdata },
251 { .compatible = "ti,am4372-d_can", .data = &am3352_dcan_drvdata },
252 { /* sentinel */ },
253};
254MODULE_DEVICE_TABLE(of, c_can_of_table);
255
256static int c_can_plat_probe(struct platform_device *pdev)
257{
258 int ret;
259 void __iomem *addr;
260 struct net_device *dev;
261 struct c_can_priv *priv;
262 struct resource *mem;
263 int irq;
264 struct clk *clk;
265 const struct c_can_driver_data *drvdata;
266 struct device_node *np = pdev->dev.of_node;
267
268 drvdata = device_get_match_data(dev: &pdev->dev);
269
270 /* get the appropriate clk */
271 clk = devm_clk_get(dev: &pdev->dev, NULL);
272 if (IS_ERR(ptr: clk)) {
273 ret = PTR_ERR(ptr: clk);
274 goto exit;
275 }
276
277 /* get the platform data */
278 irq = platform_get_irq(pdev, 0);
279 if (irq < 0) {
280 ret = irq;
281 goto exit;
282 }
283
284 addr = devm_platform_get_and_ioremap_resource(pdev, index: 0, res: &mem);
285 if (IS_ERR(ptr: addr)) {
286 ret = PTR_ERR(ptr: addr);
287 goto exit;
288 }
289
290 /* allocate the c_can device */
291 dev = alloc_c_can_dev(msg_obj_num: drvdata->msg_obj_num);
292 if (!dev) {
293 ret = -ENOMEM;
294 goto exit;
295 }
296
297 priv = netdev_priv(dev);
298 switch (drvdata->id) {
299 case BOSCH_C_CAN:
300 priv->regs = reg_map_c_can;
301 switch (mem->flags & IORESOURCE_MEM_TYPE_MASK) {
302 case IORESOURCE_MEM_32BIT:
303 priv->read_reg = c_can_plat_read_reg_aligned_to_32bit;
304 priv->write_reg = c_can_plat_write_reg_aligned_to_32bit;
305 priv->read_reg32 = c_can_plat_read_reg32;
306 priv->write_reg32 = c_can_plat_write_reg32;
307 break;
308 case IORESOURCE_MEM_16BIT:
309 default:
310 priv->read_reg = c_can_plat_read_reg_aligned_to_16bit;
311 priv->write_reg = c_can_plat_write_reg_aligned_to_16bit;
312 priv->read_reg32 = c_can_plat_read_reg32;
313 priv->write_reg32 = c_can_plat_write_reg32;
314 break;
315 }
316 break;
317 case BOSCH_D_CAN:
318 priv->regs = reg_map_d_can;
319 priv->read_reg = c_can_plat_read_reg_aligned_to_16bit;
320 priv->write_reg = c_can_plat_write_reg_aligned_to_16bit;
321 priv->read_reg32 = d_can_plat_read_reg32;
322 priv->write_reg32 = d_can_plat_write_reg32;
323
324 /* Check if we need custom RAMINIT via syscon. Mostly for TI
325 * platforms. Only supported with DT boot.
326 */
327 if (np && of_property_read_bool(np, propname: "syscon-raminit")) {
328 u32 id;
329 struct c_can_raminit *raminit = &priv->raminit_sys;
330
331 ret = -EINVAL;
332 raminit->syscon = syscon_regmap_lookup_by_phandle(np,
333 property: "syscon-raminit");
334 if (IS_ERR(ptr: raminit->syscon)) {
335 /* can fail with -EPROBE_DEFER */
336 ret = PTR_ERR(ptr: raminit->syscon);
337 free_c_can_dev(dev);
338 return ret;
339 }
340
341 if (of_property_read_u32_index(np, propname: "syscon-raminit", index: 1,
342 out_value: &raminit->reg)) {
343 dev_err(&pdev->dev,
344 "couldn't get the RAMINIT reg. offset!\n");
345 goto exit_free_device;
346 }
347
348 if (of_property_read_u32_index(np, propname: "syscon-raminit", index: 2,
349 out_value: &id)) {
350 dev_err(&pdev->dev,
351 "couldn't get the CAN instance ID\n");
352 goto exit_free_device;
353 }
354
355 if (id >= drvdata->raminit_num) {
356 dev_err(&pdev->dev,
357 "Invalid CAN instance ID\n");
358 goto exit_free_device;
359 }
360
361 raminit->bits = drvdata->raminit_bits[id];
362 raminit->needs_pulse = drvdata->raminit_pulse;
363
364 priv->raminit = c_can_hw_raminit_syscon;
365 } else {
366 priv->raminit = c_can_hw_raminit;
367 }
368 break;
369 default:
370 ret = -EINVAL;
371 goto exit_free_device;
372 }
373
374 dev->irq = irq;
375 priv->base = addr;
376 priv->device = &pdev->dev;
377 priv->can.clock.freq = clk_get_rate(clk);
378 priv->type = drvdata->id;
379
380 platform_set_drvdata(pdev, data: dev);
381 SET_NETDEV_DEV(dev, &pdev->dev);
382
383 pm_runtime_enable(dev: priv->device);
384 ret = register_c_can_dev(dev);
385 if (ret) {
386 dev_err(&pdev->dev, "registering %s failed (err=%d)\n",
387 KBUILD_MODNAME, ret);
388 goto exit_free_device;
389 }
390
391 dev_info(&pdev->dev, "%s device registered (regs=%p, irq=%d)\n",
392 KBUILD_MODNAME, priv->base, dev->irq);
393 return 0;
394
395exit_free_device:
396 pm_runtime_disable(dev: priv->device);
397 free_c_can_dev(dev);
398exit:
399 dev_err(&pdev->dev, "probe failed\n");
400
401 return ret;
402}
403
404static void c_can_plat_remove(struct platform_device *pdev)
405{
406 struct net_device *dev = platform_get_drvdata(pdev);
407 struct c_can_priv *priv = netdev_priv(dev);
408
409 unregister_c_can_dev(dev);
410 pm_runtime_disable(dev: priv->device);
411 free_c_can_dev(dev);
412}
413
414#ifdef CONFIG_PM
415static int c_can_suspend(struct platform_device *pdev, pm_message_t state)
416{
417 int ret;
418 struct net_device *ndev = platform_get_drvdata(pdev);
419 struct c_can_priv *priv = netdev_priv(dev: ndev);
420
421 if (priv->type != BOSCH_D_CAN) {
422 dev_warn(&pdev->dev, "Not supported\n");
423 return 0;
424 }
425
426 if (netif_running(dev: ndev)) {
427 netif_stop_queue(dev: ndev);
428 netif_device_detach(dev: ndev);
429 }
430
431 ret = c_can_power_down(dev: ndev);
432 if (ret) {
433 netdev_err(dev: ndev, format: "failed to enter power down mode\n");
434 return ret;
435 }
436
437 priv->can.state = CAN_STATE_SLEEPING;
438
439 return 0;
440}
441
442static int c_can_resume(struct platform_device *pdev)
443{
444 int ret;
445 struct net_device *ndev = platform_get_drvdata(pdev);
446 struct c_can_priv *priv = netdev_priv(dev: ndev);
447
448 if (priv->type != BOSCH_D_CAN) {
449 dev_warn(&pdev->dev, "Not supported\n");
450 return 0;
451 }
452
453 ret = c_can_power_up(dev: ndev);
454 if (ret) {
455 netdev_err(dev: ndev, format: "Still in power down mode\n");
456 return ret;
457 }
458
459 priv->can.state = CAN_STATE_ERROR_ACTIVE;
460
461 if (netif_running(dev: ndev)) {
462 netif_device_attach(dev: ndev);
463 netif_start_queue(dev: ndev);
464 }
465
466 return 0;
467}
468#else
469#define c_can_suspend NULL
470#define c_can_resume NULL
471#endif
472
473static struct platform_driver c_can_plat_driver = {
474 .driver = {
475 .name = KBUILD_MODNAME,
476 .of_match_table = c_can_of_table,
477 },
478 .probe = c_can_plat_probe,
479 .remove_new = c_can_plat_remove,
480 .suspend = c_can_suspend,
481 .resume = c_can_resume,
482 .id_table = c_can_id_table,
483};
484
485module_platform_driver(c_can_plat_driver);
486
487MODULE_AUTHOR("Bhupesh Sharma <bhupesh.sharma@st.com>");
488MODULE_LICENSE("GPL v2");
489MODULE_DESCRIPTION("Platform CAN bus driver for Bosch C_CAN controller");
490

source code of linux/drivers/net/can/c_can/c_can_platform.c