1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2008 Sebastian Haas (initial chardev implementation)
4  * Copyright (C) 2010 Markus Plessing <plessing@ems-wuensche.com>
5  * Rework for mainline by Oliver Hartkopp <socketcan@hartkopp.net>
6  */
7 
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/interrupt.h>
11 #include <linux/netdevice.h>
12 #include <linux/delay.h>
13 #include <linux/io.h>
14 #include <pcmcia/cistpl.h>
15 #include <pcmcia/ds.h>
16 #include <linux/can.h>
17 #include <linux/can/dev.h>
18 #include "sja1000.h"
19 
20 #define DRV_NAME "ems_pcmcia"
21 
22 MODULE_AUTHOR("Markus Plessing <plessing@ems-wuensche.com>");
23 MODULE_DESCRIPTION("Socket-CAN driver for EMS CPC-CARD cards");
24 MODULE_LICENSE("GPL v2");
25 
26 #define EMS_PCMCIA_MAX_CHAN 2
27 
28 struct ems_pcmcia_card {
29 	int channels;
30 	struct pcmcia_device *pcmcia_dev;
31 	struct net_device *net_dev[EMS_PCMCIA_MAX_CHAN];
32 	void __iomem *base_addr;
33 };
34 
35 #define EMS_PCMCIA_CAN_CLOCK (16000000 / 2)
36 
37 /*
38  * The board configuration is probably following:
39  * RX1 is connected to ground.
40  * TX1 is not connected.
41  * CLKO is not connected.
42  * Setting the OCR register to 0xDA is a good idea.
43  * This means  normal output mode , push-pull and the correct polarity.
44  */
45 #define EMS_PCMCIA_OCR (OCR_TX0_PUSHPULL | OCR_TX1_PUSHPULL)
46 
47 /*
48  * In the CDR register, you should set CBP to 1.
49  * You will probably also want to set the clock divider value to 7
50  * (meaning direct oscillator output) because the second SJA1000 chip
51  * is driven by the first one CLKOUT output.
52  */
53 #define EMS_PCMCIA_CDR (CDR_CBP | CDR_CLKOUT_MASK)
54 #define EMS_PCMCIA_MEM_SIZE 4096 /* Size of the remapped io-memory */
55 #define EMS_PCMCIA_CAN_BASE_OFFSET 0x100 /* Offset where controllers starts */
56 #define EMS_PCMCIA_CAN_CTRL_SIZE 0x80 /* Memory size for each controller */
57 
58 #define EMS_CMD_RESET 0x00 /* Perform a reset of the card */
59 #define EMS_CMD_MAP   0x03 /* Map CAN controllers into card' memory */
60 #define EMS_CMD_UMAP  0x02 /* Unmap CAN controllers from card' memory */
61 
62 static struct pcmcia_device_id ems_pcmcia_tbl[] = {
63 	PCMCIA_DEVICE_PROD_ID123("EMS_T_W", "CPC-Card", "V2.0", 0xeab1ea23,
64 				 0xa338573f, 0xe4575800),
65 	PCMCIA_DEVICE_NULL,
66 };
67 
68 MODULE_DEVICE_TABLE(pcmcia, ems_pcmcia_tbl);
69 
70 static u8 ems_pcmcia_read_reg(const struct sja1000_priv *priv, int port)
71 {
72 	return readb(priv->reg_base + port);
73 }
74 
75 static void ems_pcmcia_write_reg(const struct sja1000_priv *priv, int port,
76 				 u8 val)
77 {
78 	writeb(val, priv->reg_base + port);
79 }
80 
81 static irqreturn_t ems_pcmcia_interrupt(int irq, void *dev_id)
82 {
83 	struct ems_pcmcia_card *card = dev_id;
84 	struct net_device *dev;
85 	irqreturn_t retval = IRQ_NONE;
86 	int i, again;
87 
88 	/* Card not present */
89 	if (readw(card->base_addr) != 0xAA55)
90 		return IRQ_HANDLED;
91 
92 	do {
93 		again = 0;
94 
95 		/* Check interrupt for each channel */
96 		for (i = 0; i < card->channels; i++) {
97 			dev = card->net_dev[i];
98 			if (!dev)
99 				continue;
100 
101 			if (sja1000_interrupt(irq, dev) == IRQ_HANDLED)
102 				again = 1;
103 		}
104 		/* At least one channel handled the interrupt */
105 		if (again)
106 			retval = IRQ_HANDLED;
107 
108 	} while (again);
109 
110 	return retval;
111 }
112 
113 /*
114  * Check if a CAN controller is present at the specified location
115  * by trying to set 'em into the PeliCAN mode
116  */
117 static inline int ems_pcmcia_check_chan(struct sja1000_priv *priv)
118 {
119 	/* Make sure SJA1000 is in reset mode */
120 	ems_pcmcia_write_reg(priv, SJA1000_MOD, 1);
121 	ems_pcmcia_write_reg(priv, SJA1000_CDR, CDR_PELICAN);
122 
123 	/* read reset-values */
124 	if (ems_pcmcia_read_reg(priv, SJA1000_CDR) == CDR_PELICAN)
125 		return 1;
126 
127 	return 0;
128 }
129 
130 static void ems_pcmcia_del_card(struct pcmcia_device *pdev)
131 {
132 	struct ems_pcmcia_card *card = pdev->priv;
133 	struct net_device *dev;
134 	int i;
135 
136 	free_irq(pdev->irq, card);
137 
138 	for (i = 0; i < card->channels; i++) {
139 		dev = card->net_dev[i];
140 		if (!dev)
141 			continue;
142 
143 		printk(KERN_INFO "%s: removing %s on channel #%d\n",
144 		       DRV_NAME, dev->name, i);
145 		unregister_sja1000dev(dev);
146 		free_sja1000dev(dev);
147 	}
148 
149 	writeb(EMS_CMD_UMAP, card->base_addr);
150 	iounmap(card->base_addr);
151 	kfree(card);
152 
153 	pdev->priv = NULL;
154 }
155 
156 /*
157  * Probe PCI device for EMS CAN signature and register each available
158  * CAN channel to SJA1000 Socket-CAN subsystem.
159  */
160 static int ems_pcmcia_add_card(struct pcmcia_device *pdev, unsigned long base)
161 {
162 	struct sja1000_priv *priv;
163 	struct net_device *dev;
164 	struct ems_pcmcia_card *card;
165 	int err, i;
166 
167 	/* Allocating card structures to hold addresses, ... */
168 	card = kzalloc(sizeof(struct ems_pcmcia_card), GFP_KERNEL);
169 	if (!card)
170 		return -ENOMEM;
171 
172 	pdev->priv = card;
173 	card->channels = 0;
174 
175 	card->base_addr = ioremap(base, EMS_PCMCIA_MEM_SIZE);
176 	if (!card->base_addr) {
177 		err = -ENOMEM;
178 		goto failure_cleanup;
179 	}
180 
181 	/* Check for unique EMS CAN signature */
182 	if (readw(card->base_addr) != 0xAA55) {
183 		err = -ENODEV;
184 		goto failure_cleanup;
185 	}
186 
187 	/* Request board reset */
188 	writeb(EMS_CMD_RESET, card->base_addr);
189 
190 	/* Make sure CAN controllers are mapped into card's memory space */
191 	writeb(EMS_CMD_MAP, card->base_addr);
192 
193 	/* Detect available channels */
194 	for (i = 0; i < EMS_PCMCIA_MAX_CHAN; i++) {
195 		dev = alloc_sja1000dev(0);
196 		if (!dev) {
197 			err = -ENOMEM;
198 			goto failure_cleanup;
199 		}
200 
201 		card->net_dev[i] = dev;
202 		priv = netdev_priv(dev);
203 		priv->priv = card;
204 		SET_NETDEV_DEV(dev, &pdev->dev);
205 		dev->dev_id = i;
206 
207 		priv->irq_flags = IRQF_SHARED;
208 		dev->irq = pdev->irq;
209 		priv->reg_base = card->base_addr + EMS_PCMCIA_CAN_BASE_OFFSET +
210 			(i * EMS_PCMCIA_CAN_CTRL_SIZE);
211 
212 		/* Check if channel is present */
213 		if (ems_pcmcia_check_chan(priv)) {
214 			priv->read_reg  = ems_pcmcia_read_reg;
215 			priv->write_reg = ems_pcmcia_write_reg;
216 			priv->can.clock.freq = EMS_PCMCIA_CAN_CLOCK;
217 			priv->ocr = EMS_PCMCIA_OCR;
218 			priv->cdr = EMS_PCMCIA_CDR;
219 			priv->flags |= SJA1000_CUSTOM_IRQ_HANDLER;
220 
221 			/* Register SJA1000 device */
222 			err = register_sja1000dev(dev);
223 			if (err) {
224 				free_sja1000dev(dev);
225 				goto failure_cleanup;
226 			}
227 
228 			card->channels++;
229 
230 			printk(KERN_INFO "%s: registered %s on channel "
231 			       "#%d at 0x%p, irq %d\n", DRV_NAME, dev->name,
232 			       i, priv->reg_base, dev->irq);
233 		} else
234 			free_sja1000dev(dev);
235 	}
236 
237 	if (!card->channels) {
238 		err = -ENODEV;
239 		goto failure_cleanup;
240 	}
241 
242 	err = request_irq(pdev->irq, &ems_pcmcia_interrupt, IRQF_SHARED,
243 			  DRV_NAME, card);
244 	if (!err)
245 		return 0;
246 
247 failure_cleanup:
248 	ems_pcmcia_del_card(pdev);
249 	return err;
250 }
251 
252 /*
253  * Setup PCMCIA socket and probe for EMS CPC-CARD
254  */
255 static int ems_pcmcia_probe(struct pcmcia_device *dev)
256 {
257 	int csval;
258 
259 	/* General socket configuration */
260 	dev->config_flags |= CONF_ENABLE_IRQ;
261 	dev->config_index = 1;
262 	dev->config_regs = PRESENT_OPTION;
263 
264 	/* The io structure describes IO port mapping */
265 	dev->resource[0]->end = 16;
266 	dev->resource[0]->flags |= IO_DATA_PATH_WIDTH_8;
267 	dev->resource[1]->end = 16;
268 	dev->resource[1]->flags |= IO_DATA_PATH_WIDTH_16;
269 	dev->io_lines = 5;
270 
271 	/* Allocate a memory window */
272 	dev->resource[2]->flags =
273 		(WIN_DATA_WIDTH_8 | WIN_MEMORY_TYPE_CM | WIN_ENABLE);
274 	dev->resource[2]->start = dev->resource[2]->end = 0;
275 
276 	csval = pcmcia_request_window(dev, dev->resource[2], 0);
277 	if (csval) {
278 		dev_err(&dev->dev, "pcmcia_request_window failed (err=%d)\n",
279 			csval);
280 		return 0;
281 	}
282 
283 	csval = pcmcia_map_mem_page(dev, dev->resource[2], dev->config_base);
284 	if (csval) {
285 		dev_err(&dev->dev, "pcmcia_map_mem_page failed (err=%d)\n",
286 			csval);
287 		return 0;
288 	}
289 
290 	csval = pcmcia_enable_device(dev);
291 	if (csval) {
292 		dev_err(&dev->dev, "pcmcia_enable_device failed (err=%d)\n",
293 			csval);
294 		return 0;
295 	}
296 
297 	ems_pcmcia_add_card(dev, dev->resource[2]->start);
298 	return 0;
299 }
300 
301 /*
302  * Release claimed resources
303  */
304 static void ems_pcmcia_remove(struct pcmcia_device *dev)
305 {
306 	ems_pcmcia_del_card(dev);
307 	pcmcia_disable_device(dev);
308 }
309 
310 static struct pcmcia_driver ems_pcmcia_driver = {
311 	.name = DRV_NAME,
312 	.probe = ems_pcmcia_probe,
313 	.remove = ems_pcmcia_remove,
314 	.id_table = ems_pcmcia_tbl,
315 };
316 module_pcmcia_driver(ems_pcmcia_driver);
317