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
22MODULE_AUTHOR("Markus Plessing <plessing@ems-wuensche.com>");
23MODULE_DESCRIPTION("Socket-CAN driver for EMS CPC-CARD cards");
24MODULE_SUPPORTED_DEVICE("EMS CPC-CARD CAN card");
25MODULE_LICENSE("GPL v2");
26
27#define EMS_PCMCIA_MAX_CHAN 2
28
29struct 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
63static 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
69MODULE_DEVICE_TABLE(pcmcia, ems_pcmcia_tbl);
70
71static u8 ems_pcmcia_read_reg(const struct sja1000_priv *priv, int port)
72{
73	return readb(priv->reg_base + port);
74}
75
76static 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
82static 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 */
118static 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
131static 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 */
161static 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	if (!card->channels) {
239		err = -ENODEV;
240		goto failure_cleanup;
241	}
242
243	err = request_irq(pdev->irq, &ems_pcmcia_interrupt, IRQF_SHARED,
244			  DRV_NAME, card);
245	if (!err)
246		return 0;
247
248failure_cleanup:
249	ems_pcmcia_del_card(pdev);
250	return err;
251}
252
253/*
254 * Setup PCMCIA socket and probe for EMS CPC-CARD
255 */
256static int ems_pcmcia_probe(struct pcmcia_device *dev)
257{
258	int csval;
259
260	/* General socket configuration */
261	dev->config_flags |= CONF_ENABLE_IRQ;
262	dev->config_index = 1;
263	dev->config_regs = PRESENT_OPTION;
264
265	/* The io structure describes IO port mapping */
266	dev->resource[0]->end = 16;
267	dev->resource[0]->flags |= IO_DATA_PATH_WIDTH_8;
268	dev->resource[1]->end = 16;
269	dev->resource[1]->flags |= IO_DATA_PATH_WIDTH_16;
270	dev->io_lines = 5;
271
272	/* Allocate a memory window */
273	dev->resource[2]->flags =
274		(WIN_DATA_WIDTH_8 | WIN_MEMORY_TYPE_CM | WIN_ENABLE);
275	dev->resource[2]->start = dev->resource[2]->end = 0;
276
277	csval = pcmcia_request_window(dev, dev->resource[2], 0);
278	if (csval) {
279		dev_err(&dev->dev, "pcmcia_request_window failed (err=%d)\n",
280			csval);
281		return 0;
282	}
283
284	csval = pcmcia_map_mem_page(dev, dev->resource[2], dev->config_base);
285	if (csval) {
286		dev_err(&dev->dev, "pcmcia_map_mem_page failed (err=%d)\n",
287			csval);
288		return 0;
289	}
290
291	csval = pcmcia_enable_device(dev);
292	if (csval) {
293		dev_err(&dev->dev, "pcmcia_enable_device failed (err=%d)\n",
294			csval);
295		return 0;
296	}
297
298	ems_pcmcia_add_card(dev, dev->resource[2]->start);
299	return 0;
300}
301
302/*
303 * Release claimed resources
304 */
305static void ems_pcmcia_remove(struct pcmcia_device *dev)
306{
307	ems_pcmcia_del_card(dev);
308	pcmcia_disable_device(dev);
309}
310
311static struct pcmcia_driver ems_pcmcia_driver = {
312	.name = DRV_NAME,
313	.probe = ems_pcmcia_probe,
314	.remove = ems_pcmcia_remove,
315	.id_table = ems_pcmcia_tbl,
316};
317module_pcmcia_driver(ems_pcmcia_driver);
318