mpc5xxx_can.c revision 24cfbcbabf1faef396ee45b13b25c85d2d17b90d 
1/*
2 * CAN bus driver for the Freescale MPC5xxx embedded CPU.
3 *
4 * Copyright (C) 2004-2005 Andrey Volkov <avolkov@varma-el.com>,
5 *                         Varma Electronics Oy
6 * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
7 * Copyright (C) 2009 Wolfram Sang, Pengutronix <w.sang@pengutronix.de>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the version 2 of the GNU General Public License
11 * as published by the Free Software Foundation
12 *
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
21 */
22
23#include <linux/kernel.h>
24#include <linux/module.h>
25#include <linux/interrupt.h>
26#include <linux/platform_device.h>
27#include <linux/netdevice.h>
28#include <linux/can.h>
29#include <linux/can/dev.h>
30#include <linux/of_platform.h>
31#include <sysdev/fsl_soc.h>
32#include <linux/io.h>
33#include <asm/mpc52xx.h>
34
35#include "mscan.h"
36
37#define DRV_NAME "mpc5xxx_can"
38
39static struct of_device_id mpc52xx_cdm_ids[] __devinitdata = {
40	{ .compatible = "fsl,mpc5200-cdm", },
41	{}
42};
43
44/*
45 * Get frequency of the MSCAN clock source
46 *
47 * Either the oscillator clock (SYS_XTAL_IN) or the IP bus clock (IP_CLK)
48 * can be selected. According to the MPC5200 user's manual, the oscillator
49 * clock is the better choice as it has less jitter but due to a hardware
50 * bug, it can not be selected for the old MPC5200 Rev. A chips.
51 */
52
53static unsigned int  __devinit mpc52xx_can_clock_freq(struct of_device *of,
54						      int clock_src)
55{
56	unsigned int pvr;
57	struct mpc52xx_cdm  __iomem *cdm;
58	struct device_node *np_cdm;
59	unsigned int freq;
60	u32 val;
61
62	pvr = mfspr(SPRN_PVR);
63
64	freq = mpc5xxx_get_bus_frequency(of->node);
65	if (!freq)
66		return 0;
67
68	if (clock_src == MSCAN_CLKSRC_BUS || pvr == 0x80822011)
69		return freq;
70
71	/* Determine SYS_XTAL_IN frequency from the clock domain settings */
72	np_cdm = of_find_matching_node(NULL, mpc52xx_cdm_ids);
73	if (!np_cdm) {
74		dev_err(&of->dev, "can't get clock node!\n");
75		return 0;
76	}
77	cdm = of_iomap(np_cdm, 0);
78	of_node_put(np_cdm);
79
80	if (in_8(&cdm->ipb_clk_sel) & 0x1)
81		freq *= 2;
82	val = in_be32(&cdm->rstcfg);
83
84	freq *= (val & (1 << 5)) ? 8 : 4;
85	freq /= (val & (1 << 6)) ? 12 : 16;
86
87	iounmap(cdm);
88
89	return freq;
90}
91
92static int __devinit mpc5xxx_can_probe(struct of_device *ofdev,
93				       const struct of_device_id *id)
94{
95	struct device_node *np = ofdev->node;
96	struct net_device *dev;
97	struct mscan_priv *priv;
98	void __iomem *base;
99	const char *clk_src;
100	int err, irq, clock_src;
101
102	base = of_iomap(ofdev->node, 0);
103	if (!base) {
104		dev_err(&ofdev->dev, "couldn't ioremap\n");
105		err = -ENOMEM;
106		goto exit_release_mem;
107	}
108
109	irq = irq_of_parse_and_map(np, 0);
110	if (!irq) {
111		dev_err(&ofdev->dev, "no irq found\n");
112		err = -ENODEV;
113		goto exit_unmap_mem;
114	}
115
116	dev = alloc_mscandev();
117	if (!dev) {
118		err = -ENOMEM;
119		goto exit_dispose_irq;
120	}
121
122	priv = netdev_priv(dev);
123	priv->reg_base = base;
124	dev->irq = irq;
125
126	/*
127	 * Either the oscillator clock (SYS_XTAL_IN) or the IP bus clock
128	 * (IP_CLK) can be selected as MSCAN clock source. According to
129	 * the MPC5200 user's manual, the oscillator clock is the better
130	 * choice as it has less jitter. For this reason, it is selected
131	 * by default.
132	 */
133	clk_src = of_get_property(np, "fsl,mscan-clock-source", NULL);
134	if (clk_src && strcmp(clk_src, "ip") == 0)
135		clock_src = MSCAN_CLKSRC_BUS;
136	else
137		clock_src = MSCAN_CLKSRC_XTAL;
138	priv->can.clock.freq = mpc52xx_can_clock_freq(ofdev, clock_src);
139	if (!priv->can.clock.freq) {
140		dev_err(&ofdev->dev, "couldn't get MSCAN clock frequency\n");
141		err = -ENODEV;
142		goto exit_free_mscan;
143	}
144
145	SET_NETDEV_DEV(dev, &ofdev->dev);
146
147	err = register_mscandev(dev, clock_src);
148	if (err) {
149		dev_err(&ofdev->dev, "registering %s failed (err=%d)\n",
150			DRV_NAME, err);
151		goto exit_free_mscan;
152	}
153
154	dev_set_drvdata(&ofdev->dev, dev);
155
156	dev_info(&ofdev->dev, "MSCAN at 0x%p, irq %d, clock %d Hz\n",
157		 priv->reg_base, dev->irq, priv->can.clock.freq);
158
159	return 0;
160
161exit_free_mscan:
162	free_candev(dev);
163exit_dispose_irq:
164	irq_dispose_mapping(irq);
165exit_unmap_mem:
166	iounmap(base);
167exit_release_mem:
168	return err;
169}
170
171static int __devexit mpc5xxx_can_remove(struct of_device *ofdev)
172{
173	struct net_device *dev = dev_get_drvdata(&ofdev->dev);
174	struct mscan_priv *priv = netdev_priv(dev);
175
176	dev_set_drvdata(&ofdev->dev, NULL);
177
178	unregister_mscandev(dev);
179	iounmap(priv->reg_base);
180	irq_dispose_mapping(dev->irq);
181	free_candev(dev);
182
183	return 0;
184}
185
186#ifdef CONFIG_PM
187static struct mscan_regs saved_regs;
188static int mpc5xxx_can_suspend(struct of_device *ofdev, pm_message_t state)
189{
190	struct net_device *dev = dev_get_drvdata(&ofdev->dev);
191	struct mscan_priv *priv = netdev_priv(dev);
192	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
193
194	_memcpy_fromio(&saved_regs, regs, sizeof(*regs));
195
196	return 0;
197}
198
199static int mpc5xxx_can_resume(struct of_device *ofdev)
200{
201	struct net_device *dev = dev_get_drvdata(&ofdev->dev);
202	struct mscan_priv *priv = netdev_priv(dev);
203	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
204
205	regs->canctl0 |= MSCAN_INITRQ;
206	while (!(regs->canctl1 & MSCAN_INITAK))
207		udelay(10);
208
209	regs->canctl1 = saved_regs.canctl1;
210	regs->canbtr0 = saved_regs.canbtr0;
211	regs->canbtr1 = saved_regs.canbtr1;
212	regs->canidac = saved_regs.canidac;
213
214	/* restore masks, buffers etc. */
215	_memcpy_toio(&regs->canidar1_0, (void *)&saved_regs.canidar1_0,
216		     sizeof(*regs) - offsetof(struct mscan_regs, canidar1_0));
217
218	regs->canctl0 &= ~MSCAN_INITRQ;
219	regs->cantbsel = saved_regs.cantbsel;
220	regs->canrier = saved_regs.canrier;
221	regs->cantier = saved_regs.cantier;
222	regs->canctl0 = saved_regs.canctl0;
223
224	return 0;
225}
226#endif
227
228static struct of_device_id __devinitdata mpc5xxx_can_table[] = {
229	{.compatible = "fsl,mpc5200-mscan"},
230	{},
231};
232
233static struct of_platform_driver mpc5xxx_can_driver = {
234	.owner = THIS_MODULE,
235	.name = "mpc5xxx_can",
236	.probe = mpc5xxx_can_probe,
237	.remove = __devexit_p(mpc5xxx_can_remove),
238#ifdef CONFIG_PM
239	.suspend = mpc5xxx_can_suspend,
240	.resume = mpc5xxx_can_resume,
241#endif
242	.match_table = mpc5xxx_can_table,
243};
244
245static int __init mpc5xxx_can_init(void)
246{
247	return of_register_platform_driver(&mpc5xxx_can_driver);
248}
249module_init(mpc5xxx_can_init);
250
251static void __exit mpc5xxx_can_exit(void)
252{
253	return of_unregister_platform_driver(&mpc5xxx_can_driver);
254};
255module_exit(mpc5xxx_can_exit);
256
257MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
258MODULE_DESCRIPTION("Freescale MPC5200 CAN driver");
259MODULE_LICENSE("GPL v2");
260