1/*
2 * Xilinx XPS PS/2 device driver
3 *
4 * (c) 2005 MontaVista Software, Inc.
5 * (c) 2008 Xilinx, Inc.
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; either version 2 of the License, or (at your
10 * option) any later version.
11 *
12 * You should have received a copy of the GNU General Public License along
13 * with this program; if not, write to the Free Software Foundation, Inc.,
14 * 675 Mass Ave, Cambridge, MA 02139, USA.
15 */
16
17
18#include <linux/module.h>
19#include <linux/serio.h>
20#include <linux/interrupt.h>
21#include <linux/errno.h>
22#include <linux/slab.h>
23#include <linux/init.h>
24#include <linux/list.h>
25#include <linux/io.h>
26#include <linux/of_address.h>
27#include <linux/of_device.h>
28#include <linux/of_platform.h>
29
30#define DRIVER_NAME		"xilinx_ps2"
31
32/* Register offsets for the xps2 device */
33#define XPS2_SRST_OFFSET	0x00000000 /* Software Reset register */
34#define XPS2_STATUS_OFFSET	0x00000004 /* Status register */
35#define XPS2_RX_DATA_OFFSET	0x00000008 /* Receive Data register */
36#define XPS2_TX_DATA_OFFSET	0x0000000C /* Transmit Data register */
37#define XPS2_GIER_OFFSET	0x0000002C /* Global Interrupt Enable reg */
38#define XPS2_IPISR_OFFSET	0x00000030 /* Interrupt Status register */
39#define XPS2_IPIER_OFFSET	0x00000038 /* Interrupt Enable register */
40
41/* Reset Register Bit Definitions */
42#define XPS2_SRST_RESET		0x0000000A /* Software Reset  */
43
44/* Status Register Bit Positions */
45#define XPS2_STATUS_RX_FULL	0x00000001 /* Receive Full  */
46#define XPS2_STATUS_TX_FULL	0x00000002 /* Transmit Full  */
47
48/* Bit definitions for ISR/IER registers. Both the registers have the same bit
49 * definitions and are only defined once. */
50#define XPS2_IPIXR_WDT_TOUT	0x00000001 /* Watchdog Timeout Interrupt */
51#define XPS2_IPIXR_TX_NOACK	0x00000002 /* Transmit No ACK Interrupt */
52#define XPS2_IPIXR_TX_ACK	0x00000004 /* Transmit ACK (Data) Interrupt */
53#define XPS2_IPIXR_RX_OVF	0x00000008 /* Receive Overflow Interrupt */
54#define XPS2_IPIXR_RX_ERR	0x00000010 /* Receive Error Interrupt */
55#define XPS2_IPIXR_RX_FULL	0x00000020 /* Receive Data Interrupt */
56
57/* Mask for all the Transmit Interrupts */
58#define XPS2_IPIXR_TX_ALL	(XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_TX_ACK)
59
60/* Mask for all the Receive Interrupts */
61#define XPS2_IPIXR_RX_ALL	(XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR |  \
62				 XPS2_IPIXR_RX_FULL)
63
64/* Mask for all the Interrupts */
65#define XPS2_IPIXR_ALL		(XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL |  \
66				 XPS2_IPIXR_WDT_TOUT)
67
68/* Global Interrupt Enable mask */
69#define XPS2_GIER_GIE_MASK	0x80000000
70
71struct xps2data {
72	int irq;
73	spinlock_t lock;
74	void __iomem *base_address;	/* virt. address of control registers */
75	unsigned int flags;
76	struct serio serio;		/* serio */
77};
78
79/************************************/
80/* XPS PS/2 data transmission calls */
81/************************************/
82
83/**
84 * xps2_recv() - attempts to receive a byte from the PS/2 port.
85 * @drvdata:	pointer to ps2 device private data structure
86 * @byte:	address where the read data will be copied
87 *
88 * If there is any data available in the PS/2 receiver, this functions reads
89 * the data, otherwise it returns error.
90 */
91static int xps2_recv(struct xps2data *drvdata, u8 *byte)
92{
93	u32 sr;
94	int status = -1;
95
96	/* If there is data available in the PS/2 receiver, read it */
97	sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
98	if (sr & XPS2_STATUS_RX_FULL) {
99		*byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET);
100		status = 0;
101	}
102
103	return status;
104}
105
106/*********************/
107/* Interrupt handler */
108/*********************/
109static irqreturn_t xps2_interrupt(int irq, void *dev_id)
110{
111	struct xps2data *drvdata = dev_id;
112	u32 intr_sr;
113	u8 c;
114	int status;
115
116	/* Get the PS/2 interrupts and clear them */
117	intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET);
118	out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);
119
120	/* Check which interrupt is active */
121	if (intr_sr & XPS2_IPIXR_RX_OVF)
122		dev_warn(drvdata->serio.dev.parent, "receive overrun error\n");
123
124	if (intr_sr & XPS2_IPIXR_RX_ERR)
125		drvdata->flags |= SERIO_PARITY;
126
127	if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
128		drvdata->flags |= SERIO_TIMEOUT;
129
130	if (intr_sr & XPS2_IPIXR_RX_FULL) {
131		status = xps2_recv(drvdata, &c);
132
133		/* Error, if a byte is not received */
134		if (status) {
135			dev_err(drvdata->serio.dev.parent,
136				"wrong rcvd byte count (%d)\n", status);
137		} else {
138			serio_interrupt(&drvdata->serio, c, drvdata->flags);
139			drvdata->flags = 0;
140		}
141	}
142
143	return IRQ_HANDLED;
144}
145
146/*******************/
147/* serio callbacks */
148/*******************/
149
150/**
151 * sxps2_write() - sends a byte out through the PS/2 port.
152 * @pserio:	pointer to the serio structure of the PS/2 port
153 * @c:		data that needs to be written to the PS/2 port
154 *
155 * This function checks if the PS/2 transmitter is empty and sends a byte.
156 * Otherwise it returns error. Transmission fails only when nothing is connected
157 * to the PS/2 port. Thats why, we do not try to resend the data in case of a
158 * failure.
159 */
160static int sxps2_write(struct serio *pserio, unsigned char c)
161{
162	struct xps2data *drvdata = pserio->port_data;
163	unsigned long flags;
164	u32 sr;
165	int status = -1;
166
167	spin_lock_irqsave(&drvdata->lock, flags);
168
169	/* If the PS/2 transmitter is empty send a byte of data */
170	sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
171	if (!(sr & XPS2_STATUS_TX_FULL)) {
172		out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
173		status = 0;
174	}
175
176	spin_unlock_irqrestore(&drvdata->lock, flags);
177
178	return status;
179}
180
181/**
182 * sxps2_open() - called when a port is opened by the higher layer.
183 * @pserio:	pointer to the serio structure of the PS/2 device
184 *
185 * This function requests irq and enables interrupts for the PS/2 device.
186 */
187static int sxps2_open(struct serio *pserio)
188{
189	struct xps2data *drvdata = pserio->port_data;
190	int error;
191	u8 c;
192
193	error = request_irq(drvdata->irq, &xps2_interrupt, 0,
194				DRIVER_NAME, drvdata);
195	if (error) {
196		dev_err(drvdata->serio.dev.parent,
197			"Couldn't allocate interrupt %d\n", drvdata->irq);
198		return error;
199	}
200
201	/* start reception by enabling the interrupts */
202	out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
203	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
204	(void)xps2_recv(drvdata, &c);
205
206	return 0;		/* success */
207}
208
209/**
210 * sxps2_close() - frees the interrupt.
211 * @pserio:	pointer to the serio structure of the PS/2 device
212 *
213 * This function frees the irq and disables interrupts for the PS/2 device.
214 */
215static void sxps2_close(struct serio *pserio)
216{
217	struct xps2data *drvdata = pserio->port_data;
218
219	/* Disable the PS2 interrupts */
220	out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
221	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
222	free_irq(drvdata->irq, drvdata);
223}
224
225/**
226 * xps2_of_probe - probe method for the PS/2 device.
227 * @of_dev:	pointer to OF device structure
228 * @match:	pointer to the structure used for matching a device
229 *
230 * This function probes the PS/2 device in the device tree.
231 * It initializes the driver data structure and the hardware.
232 * It returns 0, if the driver is bound to the PS/2 device, or a negative
233 * value if there is an error.
234 */
235static int __devinit xps2_of_probe(struct platform_device *ofdev)
236{
237	struct resource r_irq; /* Interrupt resources */
238	struct resource r_mem; /* IO mem resources */
239	struct xps2data *drvdata;
240	struct serio *serio;
241	struct device *dev = &ofdev->dev;
242	resource_size_t remap_size, phys_addr;
243	int error;
244
245	dev_info(dev, "Device Tree Probing \'%s\'\n",
246			ofdev->dev.of_node->name);
247
248	/* Get iospace for the device */
249	error = of_address_to_resource(ofdev->dev.of_node, 0, &r_mem);
250	if (error) {
251		dev_err(dev, "invalid address\n");
252		return error;
253	}
254
255	/* Get IRQ for the device */
256	if (!of_irq_to_resource(ofdev->dev.of_node, 0, &r_irq)) {
257		dev_err(dev, "no IRQ found\n");
258		return -ENODEV;
259	}
260
261	drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL);
262	if (!drvdata) {
263		dev_err(dev, "Couldn't allocate device private record\n");
264		return -ENOMEM;
265	}
266
267	dev_set_drvdata(dev, drvdata);
268
269	spin_lock_init(&drvdata->lock);
270	drvdata->irq = r_irq.start;
271
272	phys_addr = r_mem.start;
273	remap_size = resource_size(&r_mem);
274	if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
275		dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
276			(unsigned long long)phys_addr);
277		error = -EBUSY;
278		goto failed1;
279	}
280
281	/* Fill in configuration data and add them to the list */
282	drvdata->base_address = ioremap(phys_addr, remap_size);
283	if (drvdata->base_address == NULL) {
284		dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
285			(unsigned long long)phys_addr);
286		error = -EFAULT;
287		goto failed2;
288	}
289
290	/* Disable all the interrupts, just in case */
291	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);
292
293	/* Reset the PS2 device and abort any current transaction, to make sure
294	 * we have the PS2 in a good state */
295	out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);
296
297	dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
298		 (unsigned long long)phys_addr, drvdata->base_address,
299		 drvdata->irq);
300
301	serio = &drvdata->serio;
302	serio->id.type = SERIO_8042;
303	serio->write = sxps2_write;
304	serio->open = sxps2_open;
305	serio->close = sxps2_close;
306	serio->port_data = drvdata;
307	serio->dev.parent = dev;
308	snprintf(serio->name, sizeof(serio->name),
309		 "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
310	snprintf(serio->phys, sizeof(serio->phys),
311		 "xilinxps2/serio at %08llX", (unsigned long long)phys_addr);
312
313	serio_register_port(serio);
314
315	return 0;		/* success */
316
317failed2:
318	release_mem_region(phys_addr, remap_size);
319failed1:
320	kfree(drvdata);
321	dev_set_drvdata(dev, NULL);
322
323	return error;
324}
325
326/**
327 * xps2_of_remove - unbinds the driver from the PS/2 device.
328 * @of_dev:	pointer to OF device structure
329 *
330 * This function is called if a device is physically removed from the system or
331 * if the driver module is being unloaded. It frees any resources allocated to
332 * the device.
333 */
334static int __devexit xps2_of_remove(struct platform_device *of_dev)
335{
336	struct device *dev = &of_dev->dev;
337	struct xps2data *drvdata = dev_get_drvdata(dev);
338	struct resource r_mem; /* IO mem resources */
339
340	serio_unregister_port(&drvdata->serio);
341	iounmap(drvdata->base_address);
342
343	/* Get iospace of the device */
344	if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem))
345		dev_err(dev, "invalid address\n");
346	else
347		release_mem_region(r_mem.start, resource_size(&r_mem));
348
349	kfree(drvdata);
350
351	dev_set_drvdata(dev, NULL);
352
353	return 0;
354}
355
356/* Match table for of_platform binding */
357static const struct of_device_id xps2_of_match[] __devinitconst = {
358	{ .compatible = "xlnx,xps-ps2-1.00.a", },
359	{ /* end of list */ },
360};
361MODULE_DEVICE_TABLE(of, xps2_of_match);
362
363static struct platform_driver xps2_of_driver = {
364	.driver = {
365		.name = DRIVER_NAME,
366		.owner = THIS_MODULE,
367		.of_match_table = xps2_of_match,
368	},
369	.probe		= xps2_of_probe,
370	.remove		= __devexit_p(xps2_of_remove),
371};
372module_platform_driver(xps2_of_driver);
373
374MODULE_AUTHOR("Xilinx, Inc.");
375MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
376MODULE_LICENSE("GPL");
377
378