c_can_platform.c revision f323d7a1d2868c00b2604dca36ad82e8ecbe4270 
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/clk.h>
33#include <linux/of.h>
34#include <linux/of_device.h>
35
36#include <linux/can/dev.h>
37
38#include "c_can.h"
39
40#define CAN_RAMINIT_START_MASK(i)	(0x001 << (i))
41#define CAN_RAMINIT_DONE_MASK(i)	(0x100 << (i))
42#define CAN_RAMINIT_ALL_MASK(i)		(0x101 << (i))
43static DEFINE_SPINLOCK(raminit_lock);
44/*
45 * 16-bit c_can registers can be arranged differently in the memory
46 * architecture of different implementations. For example: 16-bit
47 * registers can be aligned to a 16-bit boundary or 32-bit boundary etc.
48 * Handle the same by providing a common read/write interface.
49 */
50static u16 c_can_plat_read_reg_aligned_to_16bit(struct c_can_priv *priv,
51						enum reg index)
52{
53	return readw(priv->base + priv->regs[index]);
54}
55
56static void c_can_plat_write_reg_aligned_to_16bit(struct c_can_priv *priv,
57						enum reg index, u16 val)
58{
59	writew(val, priv->base + priv->regs[index]);
60}
61
62static u16 c_can_plat_read_reg_aligned_to_32bit(struct c_can_priv *priv,
63						enum reg index)
64{
65	return readw(priv->base + 2 * priv->regs[index]);
66}
67
68static void c_can_plat_write_reg_aligned_to_32bit(struct c_can_priv *priv,
69						enum reg index, u16 val)
70{
71	writew(val, priv->base + 2 * priv->regs[index]);
72}
73
74static void c_can_hw_raminit_wait(const struct c_can_priv *priv, u32 mask,
75				  u32 val)
76{
77	/* We look only at the bits of our instance. */
78	val &= mask;
79	while ((readl(priv->raminit_ctrlreg) & mask) != val)
80		udelay(1);
81}
82
83static void c_can_hw_raminit(const struct c_can_priv *priv, bool enable)
84{
85	u32 mask = CAN_RAMINIT_ALL_MASK(priv->instance);
86	u32 ctrl;
87
88	spin_lock(&raminit_lock);
89
90	ctrl = readl(priv->raminit_ctrlreg);
91	/* We clear the done and start bit first. The start bit is
92	 * looking at the 0 -> transition, but is not self clearing;
93	 * And we clear the init done bit as well.
94	 */
95	ctrl &= ~CAN_RAMINIT_START_MASK(priv->instance);
96	ctrl |= CAN_RAMINIT_DONE_MASK(priv->instance);
97	writel(ctrl, priv->raminit_ctrlreg);
98	ctrl &= ~CAN_RAMINIT_DONE_MASK(priv->instance);
99	c_can_hw_raminit_wait(priv, ctrl, mask);
100
101	if (enable) {
102		/* Set start bit and wait for the done bit. */
103		ctrl |= CAN_RAMINIT_START_MASK(priv->instance);
104		writel(ctrl, priv->raminit_ctrlreg);
105		ctrl |= CAN_RAMINIT_DONE_MASK(priv->instance);
106		c_can_hw_raminit_wait(priv, ctrl, mask);
107	}
108	spin_unlock(&raminit_lock);
109}
110
111static struct platform_device_id c_can_id_table[] = {
112	[BOSCH_C_CAN_PLATFORM] = {
113		.name = KBUILD_MODNAME,
114		.driver_data = BOSCH_C_CAN,
115	},
116	[BOSCH_C_CAN] = {
117		.name = "c_can",
118		.driver_data = BOSCH_C_CAN,
119	},
120	[BOSCH_D_CAN] = {
121		.name = "d_can",
122		.driver_data = BOSCH_D_CAN,
123	}, {
124	}
125};
126MODULE_DEVICE_TABLE(platform, c_can_id_table);
127
128static const struct of_device_id c_can_of_table[] = {
129	{ .compatible = "bosch,c_can", .data = &c_can_id_table[BOSCH_C_CAN] },
130	{ .compatible = "bosch,d_can", .data = &c_can_id_table[BOSCH_D_CAN] },
131	{ /* sentinel */ },
132};
133MODULE_DEVICE_TABLE(of, c_can_of_table);
134
135static int c_can_plat_probe(struct platform_device *pdev)
136{
137	int ret;
138	void __iomem *addr;
139	struct net_device *dev;
140	struct c_can_priv *priv;
141	const struct of_device_id *match;
142	const struct platform_device_id *id;
143	struct resource *mem, *res;
144	int irq;
145	struct clk *clk;
146
147	if (pdev->dev.of_node) {
148		match = of_match_device(c_can_of_table, &pdev->dev);
149		if (!match) {
150			dev_err(&pdev->dev, "Failed to find matching dt id\n");
151			ret = -EINVAL;
152			goto exit;
153		}
154		id = match->data;
155	} else {
156		id = platform_get_device_id(pdev);
157	}
158
159	/* get the appropriate clk */
160	clk = clk_get(&pdev->dev, NULL);
161	if (IS_ERR(clk)) {
162		dev_err(&pdev->dev, "no clock defined\n");
163		ret = -ENODEV;
164		goto exit;
165	}
166
167	/* get the platform data */
168	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
169	irq = platform_get_irq(pdev, 0);
170	if (!mem || irq <= 0) {
171		ret = -ENODEV;
172		goto exit_free_clk;
173	}
174
175	if (!request_mem_region(mem->start, resource_size(mem),
176				KBUILD_MODNAME)) {
177		dev_err(&pdev->dev, "resource unavailable\n");
178		ret = -ENODEV;
179		goto exit_free_clk;
180	}
181
182	addr = ioremap(mem->start, resource_size(mem));
183	if (!addr) {
184		dev_err(&pdev->dev, "failed to map can port\n");
185		ret = -ENOMEM;
186		goto exit_release_mem;
187	}
188
189	/* allocate the c_can device */
190	dev = alloc_c_can_dev();
191	if (!dev) {
192		ret = -ENOMEM;
193		goto exit_iounmap;
194	}
195
196	priv = netdev_priv(dev);
197	switch (id->driver_data) {
198	case BOSCH_C_CAN:
199		priv->regs = reg_map_c_can;
200		switch (mem->flags & IORESOURCE_MEM_TYPE_MASK) {
201		case IORESOURCE_MEM_32BIT:
202			priv->read_reg = c_can_plat_read_reg_aligned_to_32bit;
203			priv->write_reg = c_can_plat_write_reg_aligned_to_32bit;
204			break;
205		case IORESOURCE_MEM_16BIT:
206		default:
207			priv->read_reg = c_can_plat_read_reg_aligned_to_16bit;
208			priv->write_reg = c_can_plat_write_reg_aligned_to_16bit;
209			break;
210		}
211		break;
212	case BOSCH_D_CAN:
213		priv->regs = reg_map_d_can;
214		priv->can.ctrlmode_supported |= CAN_CTRLMODE_3_SAMPLES;
215		priv->read_reg = c_can_plat_read_reg_aligned_to_16bit;
216		priv->write_reg = c_can_plat_write_reg_aligned_to_16bit;
217
218		if (pdev->dev.of_node)
219			priv->instance = of_alias_get_id(pdev->dev.of_node, "d_can");
220		else
221			priv->instance = pdev->id;
222
223		res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
224		priv->raminit_ctrlreg = devm_ioremap_resource(&pdev->dev, res);
225		if (IS_ERR(priv->raminit_ctrlreg) || priv->instance < 0)
226			dev_info(&pdev->dev, "control memory is not used for raminit\n");
227		else
228			priv->raminit = c_can_hw_raminit;
229		break;
230	default:
231		ret = -EINVAL;
232		goto exit_free_device;
233	}
234
235	dev->irq = irq;
236	priv->base = addr;
237	priv->device = &pdev->dev;
238	priv->can.clock.freq = clk_get_rate(clk);
239	priv->priv = clk;
240	priv->type = id->driver_data;
241
242	platform_set_drvdata(pdev, dev);
243	SET_NETDEV_DEV(dev, &pdev->dev);
244
245	ret = register_c_can_dev(dev);
246	if (ret) {
247		dev_err(&pdev->dev, "registering %s failed (err=%d)\n",
248			KBUILD_MODNAME, ret);
249		goto exit_free_device;
250	}
251
252	dev_info(&pdev->dev, "%s device registered (regs=%p, irq=%d)\n",
253		 KBUILD_MODNAME, priv->base, dev->irq);
254	return 0;
255
256exit_free_device:
257	free_c_can_dev(dev);
258exit_iounmap:
259	iounmap(addr);
260exit_release_mem:
261	release_mem_region(mem->start, resource_size(mem));
262exit_free_clk:
263	clk_put(clk);
264exit:
265	dev_err(&pdev->dev, "probe failed\n");
266
267	return ret;
268}
269
270static int c_can_plat_remove(struct platform_device *pdev)
271{
272	struct net_device *dev = platform_get_drvdata(pdev);
273	struct c_can_priv *priv = netdev_priv(dev);
274	struct resource *mem;
275
276	unregister_c_can_dev(dev);
277
278	free_c_can_dev(dev);
279	iounmap(priv->base);
280
281	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
282	release_mem_region(mem->start, resource_size(mem));
283
284	clk_put(priv->priv);
285
286	return 0;
287}
288
289#ifdef CONFIG_PM
290static int c_can_suspend(struct platform_device *pdev, pm_message_t state)
291{
292	int ret;
293	struct net_device *ndev = platform_get_drvdata(pdev);
294	struct c_can_priv *priv = netdev_priv(ndev);
295
296	if (priv->type != BOSCH_D_CAN) {
297		dev_warn(&pdev->dev, "Not supported\n");
298		return 0;
299	}
300
301	if (netif_running(ndev)) {
302		netif_stop_queue(ndev);
303		netif_device_detach(ndev);
304	}
305
306	ret = c_can_power_down(ndev);
307	if (ret) {
308		netdev_err(ndev, "failed to enter power down mode\n");
309		return ret;
310	}
311
312	priv->can.state = CAN_STATE_SLEEPING;
313
314	return 0;
315}
316
317static int c_can_resume(struct platform_device *pdev)
318{
319	int ret;
320	struct net_device *ndev = platform_get_drvdata(pdev);
321	struct c_can_priv *priv = netdev_priv(ndev);
322
323	if (priv->type != BOSCH_D_CAN) {
324		dev_warn(&pdev->dev, "Not supported\n");
325		return 0;
326	}
327
328	ret = c_can_power_up(ndev);
329	if (ret) {
330		netdev_err(ndev, "Still in power down mode\n");
331		return ret;
332	}
333
334	priv->can.state = CAN_STATE_ERROR_ACTIVE;
335
336	if (netif_running(ndev)) {
337		netif_device_attach(ndev);
338		netif_start_queue(ndev);
339	}
340
341	return 0;
342}
343#else
344#define c_can_suspend NULL
345#define c_can_resume NULL
346#endif
347
348static struct platform_driver c_can_plat_driver = {
349	.driver = {
350		.name = KBUILD_MODNAME,
351		.owner = THIS_MODULE,
352		.of_match_table = c_can_of_table,
353	},
354	.probe = c_can_plat_probe,
355	.remove = c_can_plat_remove,
356	.suspend = c_can_suspend,
357	.resume = c_can_resume,
358	.id_table = c_can_id_table,
359};
360
361module_platform_driver(c_can_plat_driver);
362
363MODULE_AUTHOR("Bhupesh Sharma <bhupesh.sharma@st.com>");
364MODULE_LICENSE("GPL v2");
365MODULE_DESCRIPTION("Platform CAN bus driver for Bosch C_CAN controller");
366