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/list.h>
24#include <linux/io.h>
25#include <linux/of_address.h>
26#include <linux/of_device.h>
27#include <linux/of_irq.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	struct device *dev;
78};
79
80/************************************/
81/* XPS PS/2 data transmission calls */
82/************************************/
83
84/**
85 * xps2_recv() - attempts to receive a byte from the PS/2 port.
86 * @drvdata:	pointer to ps2 device private data structure
87 * @byte:	address where the read data will be copied
88 *
89 * If there is any data available in the PS/2 receiver, this functions reads
90 * the data, otherwise it returns error.
91 */
92static int xps2_recv(struct xps2data *drvdata, u8 *byte)
93{
94	u32 sr;
95	int status = -1;
96
97	/* If there is data available in the PS/2 receiver, read it */
98	sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
99	if (sr & XPS2_STATUS_RX_FULL) {
100		*byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET);
101		status = 0;
102	}
103
104	return status;
105}
106
107/*********************/
108/* Interrupt handler */
109/*********************/
110static irqreturn_t xps2_interrupt(int irq, void *dev_id)
111{
112	struct xps2data *drvdata = dev_id;
113	u32 intr_sr;
114	u8 c;
115	int status;
116
117	/* Get the PS/2 interrupts and clear them */
118	intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET);
119	out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);
120
121	/* Check which interrupt is active */
122	if (intr_sr & XPS2_IPIXR_RX_OVF)
123		dev_warn(drvdata->dev, "receive overrun error\n");
124
125	if (intr_sr & XPS2_IPIXR_RX_ERR)
126		drvdata->flags |= SERIO_PARITY;
127
128	if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
129		drvdata->flags |= SERIO_TIMEOUT;
130
131	if (intr_sr & XPS2_IPIXR_RX_FULL) {
132		status = xps2_recv(drvdata, &c);
133
134		/* Error, if a byte is not received */
135		if (status) {
136			dev_err(drvdata->dev,
137				"wrong rcvd byte count (%d)\n", status);
138		} else {
139			serio_interrupt(drvdata->serio, c, drvdata->flags);
140			drvdata->flags = 0;
141		}
142	}
143
144	return IRQ_HANDLED;
145}
146
147/*******************/
148/* serio callbacks */
149/*******************/
150
151/**
152 * sxps2_write() - sends a byte out through the PS/2 port.
153 * @pserio:	pointer to the serio structure of the PS/2 port
154 * @c:		data that needs to be written to the PS/2 port
155 *
156 * This function checks if the PS/2 transmitter is empty and sends a byte.
157 * Otherwise it returns error. Transmission fails only when nothing is connected
158 * to the PS/2 port. Thats why, we do not try to resend the data in case of a
159 * failure.
160 */
161static int sxps2_write(struct serio *pserio, unsigned char c)
162{
163	struct xps2data *drvdata = pserio->port_data;
164	unsigned long flags;
165	u32 sr;
166	int status = -1;
167
168	spin_lock_irqsave(&drvdata->lock, flags);
169
170	/* If the PS/2 transmitter is empty send a byte of data */
171	sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
172	if (!(sr & XPS2_STATUS_TX_FULL)) {
173		out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
174		status = 0;
175	}
176
177	spin_unlock_irqrestore(&drvdata->lock, flags);
178
179	return status;
180}
181
182/**
183 * sxps2_open() - called when a port is opened by the higher layer.
184 * @pserio:	pointer to the serio structure of the PS/2 device
185 *
186 * This function requests irq and enables interrupts for the PS/2 device.
187 */
188static int sxps2_open(struct serio *pserio)
189{
190	struct xps2data *drvdata = pserio->port_data;
191	int error;
192	u8 c;
193
194	error = request_irq(drvdata->irq, &xps2_interrupt, 0,
195				DRIVER_NAME, drvdata);
196	if (error) {
197		dev_err(drvdata->dev,
198			"Couldn't allocate interrupt %d\n", drvdata->irq);
199		return error;
200	}
201
202	/* start reception by enabling the interrupts */
203	out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
204	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
205	(void)xps2_recv(drvdata, &c);
206
207	return 0;		/* success */
208}
209
210/**
211 * sxps2_close() - frees the interrupt.
212 * @pserio:	pointer to the serio structure of the PS/2 device
213 *
214 * This function frees the irq and disables interrupts for the PS/2 device.
215 */
216static void sxps2_close(struct serio *pserio)
217{
218	struct xps2data *drvdata = pserio->port_data;
219
220	/* Disable the PS2 interrupts */
221	out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
222	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
223	free_irq(drvdata->irq, drvdata);
224}
225
226/**
227 * xps2_of_probe - probe method for the PS/2 device.
228 * @of_dev:	pointer to OF device structure
229 * @match:	pointer to the structure used for matching a device
230 *
231 * This function probes the PS/2 device in the device tree.
232 * It initializes the driver data structure and the hardware.
233 * It returns 0, if the driver is bound to the PS/2 device, or a negative
234 * value if there is an error.
235 */
236static int xps2_of_probe(struct platform_device *ofdev)
237{
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	unsigned int irq;
244	int error;
245
246	dev_info(dev, "Device Tree Probing \'%s\'\n",
247			ofdev->dev.of_node->name);
248
249	/* Get iospace for the device */
250	error = of_address_to_resource(ofdev->dev.of_node, 0, &r_mem);
251	if (error) {
252		dev_err(dev, "invalid address\n");
253		return error;
254	}
255
256	/* Get IRQ for the device */
257	irq = irq_of_parse_and_map(ofdev->dev.of_node, 0);
258	if (!irq) {
259		dev_err(dev, "no IRQ found\n");
260		return -ENODEV;
261	}
262
263	drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL);
264	serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
265	if (!drvdata || !serio) {
266		error = -ENOMEM;
267		goto failed1;
268	}
269
270	spin_lock_init(&drvdata->lock);
271	drvdata->irq = irq;
272	drvdata->serio = serio;
273	drvdata->dev = dev;
274
275	phys_addr = r_mem.start;
276	remap_size = resource_size(&r_mem);
277	if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
278		dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
279			(unsigned long long)phys_addr);
280		error = -EBUSY;
281		goto failed1;
282	}
283
284	/* Fill in configuration data and add them to the list */
285	drvdata->base_address = ioremap(phys_addr, remap_size);
286	if (drvdata->base_address == NULL) {
287		dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
288			(unsigned long long)phys_addr);
289		error = -EFAULT;
290		goto failed2;
291	}
292
293	/* Disable all the interrupts, just in case */
294	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);
295
296	/* Reset the PS2 device and abort any current transaction, to make sure
297	 * we have the PS2 in a good state */
298	out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);
299
300	dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
301		 (unsigned long long)phys_addr, drvdata->base_address,
302		 drvdata->irq);
303
304	serio->id.type = SERIO_8042;
305	serio->write = sxps2_write;
306	serio->open = sxps2_open;
307	serio->close = sxps2_close;
308	serio->port_data = drvdata;
309	serio->dev.parent = dev;
310	snprintf(serio->name, sizeof(serio->name),
311		 "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
312	snprintf(serio->phys, sizeof(serio->phys),
313		 "xilinxps2/serio at %08llX", (unsigned long long)phys_addr);
314
315	serio_register_port(serio);
316
317	platform_set_drvdata(ofdev, drvdata);
318	return 0;		/* success */
319
320failed2:
321	release_mem_region(phys_addr, remap_size);
322failed1:
323	kfree(serio);
324	kfree(drvdata);
325
326	return error;
327}
328
329/**
330 * xps2_of_remove - unbinds the driver from the PS/2 device.
331 * @of_dev:	pointer to OF device structure
332 *
333 * This function is called if a device is physically removed from the system or
334 * if the driver module is being unloaded. It frees any resources allocated to
335 * the device.
336 */
337static int xps2_of_remove(struct platform_device *of_dev)
338{
339	struct xps2data *drvdata = platform_get_drvdata(of_dev);
340	struct resource r_mem; /* IO mem resources */
341
342	serio_unregister_port(drvdata->serio);
343	iounmap(drvdata->base_address);
344
345	/* Get iospace of the device */
346	if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem))
347		dev_err(drvdata->dev, "invalid address\n");
348	else
349		release_mem_region(r_mem.start, resource_size(&r_mem));
350
351	kfree(drvdata);
352
353	return 0;
354}
355
356/* Match table for of_platform binding */
357static const struct of_device_id xps2_of_match[] = {
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		.of_match_table = xps2_of_match,
367	},
368	.probe		= xps2_of_probe,
369	.remove		= xps2_of_remove,
370};
371module_platform_driver(xps2_of_driver);
372
373MODULE_AUTHOR("Xilinx, Inc.");
374MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
375MODULE_LICENSE("GPL");
376
377