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 
30 MODULE_AUTHOR("Markus Plessing <plessing@ems-wuensche.com>");
31 MODULE_DESCRIPTION("Socket-CAN driver for EMS CPC-CARD cards");
32 MODULE_SUPPORTED_DEVICE("EMS CPC-CARD CAN card");
33 MODULE_LICENSE("GPL v2");
34 
35 #define EMS_PCMCIA_MAX_CHAN 2
36 
37 struct 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 
71 static 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 
77 MODULE_DEVICE_TABLE(pcmcia, ems_pcmcia_tbl);
78 
79 static u8 ems_pcmcia_read_reg(const struct sja1000_priv *priv, int port)
80 {
81 	return readb(priv->reg_base + port);
82 }
83 
84 static 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 
90 static 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  */
126 static 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, SJA1000_MOD, 1);
130 	ems_pcmcia_write_reg(priv, SJA1000_CDR, CDR_PELICAN);
131 
132 	/* read reset-values */
133 	if (ems_pcmcia_read_reg(priv, SJA1000_CDR) == CDR_PELICAN)
134 		return 1;
135 
136 	return 0;
137 }
138 
139 static 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  */
169 static 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 
250 failure_cleanup:
251 	ems_pcmcia_del_card(pdev);
252 	return err;
253 }
254 
255 /*
256  * Setup PCMCIA socket and probe for EMS CPC-CARD
257  */
258 static 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  */
307 static void ems_pcmcia_remove(struct pcmcia_device *dev)
308 {
309 	ems_pcmcia_del_card(dev);
310 	pcmcia_disable_device(dev);
311 }
312 
313 static 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 module_pcmcia_driver(ems_pcmcia_driver);
320