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