ems_pcmcia.c revision 1dd06ae8db716e17ec7e06244b858606edf378c0 
1/*
2 * Copyright (C) 2008 Sebastian Haas (initial chardev implementation)
3 * Copyright (C) 2010 Markus Plessing <plessing@ems-wuensche.com>
4 * Rework for mainline by Oliver Hartkopp <socketcan@hartkopp.net>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the version 2 of the GNU General Public License
8 * as published by the Free Software Foundation
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 */
15
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/interrupt.h>
19#include <linux/netdevice.h>
20#include <linux/delay.h>
21#include <linux/io.h>
22#include <pcmcia/cistpl.h>
23#include <pcmcia/ds.h>
24#include <linux/can.h>
25#include <linux/can/dev.h>
26#include "sja1000.h"
27
28#define DRV_NAME "ems_pcmcia"
29
30MODULE_AUTHOR("Markus Plessing <plessing@ems-wuensche.com>");
31MODULE_DESCRIPTION("Socket-CAN driver for EMS CPC-CARD cards");
32MODULE_SUPPORTED_DEVICE("EMS CPC-CARD CAN card");
33MODULE_LICENSE("GPL v2");
34
35#define EMS_PCMCIA_MAX_CHAN 2
36
37struct ems_pcmcia_card {
38	int channels;
39	struct pcmcia_device *pcmcia_dev;
40	struct net_device *net_dev[EMS_PCMCIA_MAX_CHAN];
41	void __iomem *base_addr;
42};
43
44#define EMS_PCMCIA_CAN_CLOCK (16000000 / 2)
45
46/*
47 * The board configuration is probably following:
48 * RX1 is connected to ground.
49 * TX1 is not connected.
50 * CLKO is not connected.
51 * Setting the OCR register to 0xDA is a good idea.
52 * This means  normal output mode , push-pull and the correct polarity.
53 */
54#define EMS_PCMCIA_OCR (OCR_TX0_PUSHPULL | OCR_TX1_PUSHPULL)
55
56/*
57 * In the CDR register, you should set CBP to 1.
58 * You will probably also want to set the clock divider value to 7
59 * (meaning direct oscillator output) because the second SJA1000 chip
60 * is driven by the first one CLKOUT output.
61 */
62#define EMS_PCMCIA_CDR (CDR_CBP | CDR_CLKOUT_MASK)
63#define EMS_PCMCIA_MEM_SIZE 4096 /* Size of the remapped io-memory */
64#define EMS_PCMCIA_CAN_BASE_OFFSET 0x100 /* Offset where controllers starts */
65#define EMS_PCMCIA_CAN_CTRL_SIZE 0x80 /* Memory size for each controller */
66
67#define EMS_CMD_RESET 0x00 /* Perform a reset of the card */
68#define EMS_CMD_MAP   0x03 /* Map CAN controllers into card' memory */
69#define EMS_CMD_UMAP  0x02 /* Unmap CAN controllers from card' memory */
70
71static struct pcmcia_device_id ems_pcmcia_tbl[] = {
72	PCMCIA_DEVICE_PROD_ID123("EMS_T_W", "CPC-Card", "V2.0", 0xeab1ea23,
73				 0xa338573f, 0xe4575800),
74	PCMCIA_DEVICE_NULL,
75};
76
77MODULE_DEVICE_TABLE(pcmcia, ems_pcmcia_tbl);
78
79static u8 ems_pcmcia_read_reg(const struct sja1000_priv *priv, int port)
80{
81	return readb(priv->reg_base + port);
82}
83
84static void ems_pcmcia_write_reg(const struct sja1000_priv *priv, int port,
85				 u8 val)
86{
87	writeb(val, priv->reg_base + port);
88}
89
90static irqreturn_t ems_pcmcia_interrupt(int irq, void *dev_id)
91{
92	struct ems_pcmcia_card *card = dev_id;
93	struct net_device *dev;
94	irqreturn_t retval = IRQ_NONE;
95	int i, again;
96
97	/* Card not present */
98	if (readw(card->base_addr) != 0xAA55)
99		return IRQ_HANDLED;
100
101	do {
102		again = 0;
103
104		/* Check interrupt for each channel */
105		for (i = 0; i < card->channels; i++) {
106			dev = card->net_dev[i];
107			if (!dev)
108				continue;
109
110			if (sja1000_interrupt(irq, dev) == IRQ_HANDLED)
111				again = 1;
112		}
113		/* At least one channel handled the interrupt */
114		if (again)
115			retval = IRQ_HANDLED;
116
117	} while (again);
118
119	return retval;
120}
121
122/*
123 * Check if a CAN controller is present at the specified location
124 * by trying to set 'em into the PeliCAN mode
125 */
126static inline int ems_pcmcia_check_chan(struct sja1000_priv *priv)
127{
128	/* Make sure SJA1000 is in reset mode */
129	ems_pcmcia_write_reg(priv, REG_MOD, 1);
130	ems_pcmcia_write_reg(priv, REG_CDR, CDR_PELICAN);
131
132	/* read reset-values */
133	if (ems_pcmcia_read_reg(priv, REG_CDR) == CDR_PELICAN)
134		return 1;
135
136	return 0;
137}
138
139static void ems_pcmcia_del_card(struct pcmcia_device *pdev)
140{
141	struct ems_pcmcia_card *card = pdev->priv;
142	struct net_device *dev;
143	int i;
144
145	free_irq(pdev->irq, card);
146
147	for (i = 0; i < card->channels; i++) {
148		dev = card->net_dev[i];
149		if (!dev)
150			continue;
151
152		printk(KERN_INFO "%s: removing %s on channel #%d\n",
153		       DRV_NAME, dev->name, i);
154		unregister_sja1000dev(dev);
155		free_sja1000dev(dev);
156	}
157
158	writeb(EMS_CMD_UMAP, card->base_addr);
159	iounmap(card->base_addr);
160	kfree(card);
161
162	pdev->priv = NULL;
163}
164
165/*
166 * Probe PCI device for EMS CAN signature and register each available
167 * CAN channel to SJA1000 Socket-CAN subsystem.
168 */
169static int ems_pcmcia_add_card(struct pcmcia_device *pdev, unsigned long base)
170{
171	struct sja1000_priv *priv;
172	struct net_device *dev;
173	struct ems_pcmcia_card *card;
174	int err, i;
175
176	/* Allocating card structures to hold addresses, ... */
177	card = kzalloc(sizeof(struct ems_pcmcia_card), GFP_KERNEL);
178	if (!card)
179		return -ENOMEM;
180
181	pdev->priv = card;
182	card->channels = 0;
183
184	card->base_addr = ioremap(base, EMS_PCMCIA_MEM_SIZE);
185	if (!card->base_addr) {
186		err = -ENOMEM;
187		goto failure_cleanup;
188	}
189
190	/* Check for unique EMS CAN signature */
191	if (readw(card->base_addr) != 0xAA55) {
192		err = -ENODEV;
193		goto failure_cleanup;
194	}
195
196	/* Request board reset */
197	writeb(EMS_CMD_RESET, card->base_addr);
198
199	/* Make sure CAN controllers are mapped into card's memory space */
200	writeb(EMS_CMD_MAP, card->base_addr);
201
202	/* Detect available channels */
203	for (i = 0; i < EMS_PCMCIA_MAX_CHAN; i++) {
204		dev = alloc_sja1000dev(0);
205		if (!dev) {
206			err = -ENOMEM;
207			goto failure_cleanup;
208		}
209
210		card->net_dev[i] = dev;
211		priv = netdev_priv(dev);
212		priv->priv = card;
213		SET_NETDEV_DEV(dev, &pdev->dev);
214
215		priv->irq_flags = IRQF_SHARED;
216		dev->irq = pdev->irq;
217		priv->reg_base = card->base_addr + EMS_PCMCIA_CAN_BASE_OFFSET +
218			(i * EMS_PCMCIA_CAN_CTRL_SIZE);
219
220		/* Check if channel is present */
221		if (ems_pcmcia_check_chan(priv)) {
222			priv->read_reg  = ems_pcmcia_read_reg;
223			priv->write_reg = ems_pcmcia_write_reg;
224			priv->can.clock.freq = EMS_PCMCIA_CAN_CLOCK;
225			priv->ocr = EMS_PCMCIA_OCR;
226			priv->cdr = EMS_PCMCIA_CDR;
227			priv->flags |= SJA1000_CUSTOM_IRQ_HANDLER;
228
229			/* Register SJA1000 device */
230			err = register_sja1000dev(dev);
231			if (err) {
232				free_sja1000dev(dev);
233				goto failure_cleanup;
234			}
235
236			card->channels++;
237
238			printk(KERN_INFO "%s: registered %s on channel "
239			       "#%d at 0x%p, irq %d\n", DRV_NAME, dev->name,
240			       i, priv->reg_base, dev->irq);
241		} else
242			free_sja1000dev(dev);
243	}
244
245	err = request_irq(dev->irq, &ems_pcmcia_interrupt, IRQF_SHARED,
246			  DRV_NAME, card);
247	if (!err)
248		return 0;
249
250failure_cleanup:
251	ems_pcmcia_del_card(pdev);
252	return err;
253}
254
255/*
256 * Setup PCMCIA socket and probe for EMS CPC-CARD
257 */
258static int ems_pcmcia_probe(struct pcmcia_device *dev)
259{
260	int csval;
261
262	/* General socket configuration */
263	dev->config_flags |= CONF_ENABLE_IRQ;
264	dev->config_index = 1;
265	dev->config_regs = PRESENT_OPTION;
266
267	/* The io structure describes IO port mapping */
268	dev->resource[0]->end = 16;
269	dev->resource[0]->flags |= IO_DATA_PATH_WIDTH_8;
270	dev->resource[1]->end = 16;
271	dev->resource[1]->flags |= IO_DATA_PATH_WIDTH_16;
272	dev->io_lines = 5;
273
274	/* Allocate a memory window */
275	dev->resource[2]->flags =
276		(WIN_DATA_WIDTH_8 | WIN_MEMORY_TYPE_CM | WIN_ENABLE);
277	dev->resource[2]->start = dev->resource[2]->end = 0;
278
279	csval = pcmcia_request_window(dev, dev->resource[2], 0);
280	if (csval) {
281		dev_err(&dev->dev, "pcmcia_request_window failed (err=%d)\n",
282			csval);
283		return 0;
284	}
285
286	csval = pcmcia_map_mem_page(dev, dev->resource[2], dev->config_base);
287	if (csval) {
288		dev_err(&dev->dev, "pcmcia_map_mem_page failed (err=%d)\n",
289			csval);
290		return 0;
291	}
292
293	csval = pcmcia_enable_device(dev);
294	if (csval) {
295		dev_err(&dev->dev, "pcmcia_enable_device failed (err=%d)\n",
296			csval);
297		return 0;
298	}
299
300	ems_pcmcia_add_card(dev, dev->resource[2]->start);
301	return 0;
302}
303
304/*
305 * Release claimed resources
306 */
307static void ems_pcmcia_remove(struct pcmcia_device *dev)
308{
309	ems_pcmcia_del_card(dev);
310	pcmcia_disable_device(dev);
311}
312
313static struct pcmcia_driver ems_pcmcia_driver = {
314	.name = DRV_NAME,
315	.probe = ems_pcmcia_probe,
316	.remove = ems_pcmcia_remove,
317	.id_table = ems_pcmcia_tbl,
318};
319
320static int __init ems_pcmcia_init(void)
321{
322	return pcmcia_register_driver(&ems_pcmcia_driver);
323}
324module_init(ems_pcmcia_init);
325
326static void __exit ems_pcmcia_exit(void)
327{
328	pcmcia_unregister_driver(&ems_pcmcia_driver);
329}
330module_exit(ems_pcmcia_exit);
331