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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/*
49 * Bit definitions for ISR/IER registers. Both the registers have the same bit
50 * definitions and are only defined once.
51 */
52#define XPS2_IPIXR_WDT_TOUT 0x00000001 /* Watchdog Timeout Interrupt */
53#define XPS2_IPIXR_TX_NOACK 0x00000002 /* Transmit No ACK Interrupt */
54#define XPS2_IPIXR_TX_ACK 0x00000004 /* Transmit ACK (Data) Interrupt */
55#define XPS2_IPIXR_RX_OVF 0x00000008 /* Receive Overflow Interrupt */
56#define XPS2_IPIXR_RX_ERR 0x00000010 /* Receive Error Interrupt */
57#define XPS2_IPIXR_RX_FULL 0x00000020 /* Receive Data Interrupt */
58
59/* Mask for all the Transmit Interrupts */
60#define XPS2_IPIXR_TX_ALL (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_TX_ACK)
61
62/* Mask for all the Receive Interrupts */
63#define XPS2_IPIXR_RX_ALL (XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR | \
64 XPS2_IPIXR_RX_FULL)
65
66/* Mask for all the Interrupts */
67#define XPS2_IPIXR_ALL (XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL | \
68 XPS2_IPIXR_WDT_TOUT)
69
70/* Global Interrupt Enable mask */
71#define XPS2_GIER_GIE_MASK 0x80000000
72
73struct xps2data {
74 int irq;
75 spinlock_t lock;
76 void __iomem *base_address; /* virt. address of control registers */
77 unsigned int flags;
78 struct serio *serio; /* serio */
79 struct device *dev;
80};
81
82/************************************/
83/* XPS PS/2 data transmission calls */
84/************************************/
85
86/**
87 * xps2_recv() - attempts to receive a byte from the PS/2 port.
88 * @drvdata: pointer to ps2 device private data structure
89 * @byte: address where the read data will be copied
90 *
91 * If there is any data available in the PS/2 receiver, this functions reads
92 * the data, otherwise it returns error.
93 */
94static int xps2_recv(struct xps2data *drvdata, u8 *byte)
95{
96 u32 sr;
97 int status = -1;
98
99 /* If there is data available in the PS/2 receiver, read it */
100 sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
101 if (sr & XPS2_STATUS_RX_FULL) {
102 *byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET);
103 status = 0;
104 }
105
106 return status;
107}
108
109/*********************/
110/* Interrupt handler */
111/*********************/
112static irqreturn_t xps2_interrupt(int irq, void *dev_id)
113{
114 struct xps2data *drvdata = dev_id;
115 u32 intr_sr;
116 u8 c;
117 int status;
118
119 /* Get the PS/2 interrupts and clear them */
120 intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET);
121 out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);
122
123 /* Check which interrupt is active */
124 if (intr_sr & XPS2_IPIXR_RX_OVF)
125 dev_warn(drvdata->dev, "receive overrun error\n");
126
127 if (intr_sr & XPS2_IPIXR_RX_ERR)
128 drvdata->flags |= SERIO_PARITY;
129
130 if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
131 drvdata->flags |= SERIO_TIMEOUT;
132
133 if (intr_sr & XPS2_IPIXR_RX_FULL) {
134 status = xps2_recv(drvdata, &c);
135
136 /* Error, if a byte is not received */
137 if (status) {
138 dev_err(drvdata->dev,
139 "wrong rcvd byte count (%d)\n", status);
140 } else {
141 serio_interrupt(drvdata->serio, c, drvdata->flags);
142 drvdata->flags = 0;
143 }
144 }
145
146 return IRQ_HANDLED;
147}
148
149/*******************/
150/* serio callbacks */
151/*******************/
152
153/**
154 * sxps2_write() - sends a byte out through the PS/2 port.
155 * @pserio: pointer to the serio structure of the PS/2 port
156 * @c: data that needs to be written to the PS/2 port
157 *
158 * This function checks if the PS/2 transmitter is empty and sends a byte.
159 * Otherwise it returns error. Transmission fails only when nothing is connected
160 * to the PS/2 port. Thats why, we do not try to resend the data in case of a
161 * failure.
162 */
163static int sxps2_write(struct serio *pserio, unsigned char c)
164{
165 struct xps2data *drvdata = pserio->port_data;
166 unsigned long flags;
167 u32 sr;
168 int status = -1;
169
170 spin_lock_irqsave(&drvdata->lock, flags);
171
172 /* If the PS/2 transmitter is empty send a byte of data */
173 sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
174 if (!(sr & XPS2_STATUS_TX_FULL)) {
175 out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
176 status = 0;
177 }
178
179 spin_unlock_irqrestore(&drvdata->lock, flags);
180
181 return status;
182}
183
184/**
185 * sxps2_open() - called when a port is opened by the higher layer.
186 * @pserio: pointer to the serio structure of the PS/2 device
187 *
188 * This function requests irq and enables interrupts for the PS/2 device.
189 */
190static int sxps2_open(struct serio *pserio)
191{
192 struct xps2data *drvdata = pserio->port_data;
193 int error;
194 u8 c;
195
196 error = request_irq(drvdata->irq, &xps2_interrupt, 0,
197 DRIVER_NAME, drvdata);
198 if (error) {
199 dev_err(drvdata->dev,
200 "Couldn't allocate interrupt %d\n", drvdata->irq);
201 return error;
202 }
203
204 /* start reception by enabling the interrupts */
205 out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
206 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
207 (void)xps2_recv(drvdata, &c);
208
209 return 0; /* success */
210}
211
212/**
213 * sxps2_close() - frees the interrupt.
214 * @pserio: pointer to the serio structure of the PS/2 device
215 *
216 * This function frees the irq and disables interrupts for the PS/2 device.
217 */
218static void sxps2_close(struct serio *pserio)
219{
220 struct xps2data *drvdata = pserio->port_data;
221
222 /* Disable the PS2 interrupts */
223 out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
224 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
225 free_irq(drvdata->irq, drvdata);
226}
227
228/**
229 * xps2_of_probe - probe method for the PS/2 device.
230 * @of_dev: pointer to OF device structure
231 * @match: pointer to the structure used for matching a device
232 *
233 * This function probes the PS/2 device in the device tree.
234 * It initializes the driver data structure and the hardware.
235 * It returns 0, if the driver is bound to the PS/2 device, or a negative
236 * value if there is an error.
237 */
238static int xps2_of_probe(struct platform_device *ofdev)
239{
240 struct resource r_mem; /* IO mem resources */
241 struct xps2data *drvdata;
242 struct serio *serio;
243 struct device *dev = &ofdev->dev;
244 resource_size_t remap_size, phys_addr;
245 unsigned int irq;
246 int error;
247
248 dev_info(dev, "Device Tree Probing \'%pOFn\'\n", dev->of_node);
249
250 /* Get iospace for the device */
251 error = of_address_to_resource(dev->of_node, 0, &r_mem);
252 if (error) {
253 dev_err(dev, "invalid address\n");
254 return error;
255 }
256
257 /* Get IRQ for the device */
258 irq = irq_of_parse_and_map(dev->of_node, 0);
259 if (!irq) {
260 dev_err(dev, "no IRQ found\n");
261 return -ENODEV;
262 }
263
264 drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL);
265 serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
266 if (!drvdata || !serio) {
267 error = -ENOMEM;
268 goto failed1;
269 }
270
271 spin_lock_init(&drvdata->lock);
272 drvdata->irq = irq;
273 drvdata->serio = serio;
274 drvdata->dev = dev;
275
276 phys_addr = r_mem.start;
277 remap_size = resource_size(&r_mem);
278 if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
279 dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
280 (unsigned long long)phys_addr);
281 error = -EBUSY;
282 goto failed1;
283 }
284
285 /* Fill in configuration data and add them to the list */
286 drvdata->base_address = ioremap(phys_addr, remap_size);
287 if (drvdata->base_address == NULL) {
288 dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
289 (unsigned long long)phys_addr);
290 error = -EFAULT;
291 goto failed2;
292 }
293
294 /* Disable all the interrupts, just in case */
295 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);
296
297 /*
298 * Reset the PS2 device and abort any current transaction,
299 * to make sure we have the PS2 in a good state.
300 */
301 out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);
302
303 dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
304 (unsigned long long)phys_addr, drvdata->base_address,
305 drvdata->irq);
306
307 serio->id.type = SERIO_8042;
308 serio->write = sxps2_write;
309 serio->open = sxps2_open;
310 serio->close = sxps2_close;
311 serio->port_data = drvdata;
312 serio->dev.parent = dev;
313 snprintf(serio->name, sizeof(serio->name),
314 "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
315 snprintf(serio->phys, sizeof(serio->phys),
316 "xilinxps2/serio at %08llX", (unsigned long long)phys_addr);
317
318 serio_register_port(serio);
319
320 platform_set_drvdata(ofdev, drvdata);
321 return 0; /* success */
322
323failed2:
324 release_mem_region(phys_addr, remap_size);
325failed1:
326 kfree(serio);
327 kfree(drvdata);
328
329 return error;
330}
331
332/**
333 * xps2_of_remove - unbinds the driver from the PS/2 device.
334 * @of_dev: pointer to OF device structure
335 *
336 * This function is called if a device is physically removed from the system or
337 * if the driver module is being unloaded. It frees any resources allocated to
338 * the device.
339 */
340static int xps2_of_remove(struct platform_device *of_dev)
341{
342 struct xps2data *drvdata = platform_get_drvdata(of_dev);
343 struct resource r_mem; /* IO mem resources */
344
345 serio_unregister_port(drvdata->serio);
346 iounmap(drvdata->base_address);
347
348 /* Get iospace of the device */
349 if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem))
350 dev_err(drvdata->dev, "invalid address\n");
351 else
352 release_mem_region(r_mem.start, resource_size(&r_mem));
353
354 kfree(drvdata);
355
356 return 0;
357}
358
359/* Match table for of_platform binding */
360static const struct of_device_id xps2_of_match[] = {
361 { .compatible = "xlnx,xps-ps2-1.00.a", },
362 { /* end of list */ },
363};
364MODULE_DEVICE_TABLE(of, xps2_of_match);
365
366static struct platform_driver xps2_of_driver = {
367 .driver = {
368 .name = DRIVER_NAME,
369 .of_match_table = xps2_of_match,
370 },
371 .probe = xps2_of_probe,
372 .remove = xps2_of_remove,
373};
374module_platform_driver(xps2_of_driver);
375
376MODULE_AUTHOR("Xilinx, Inc.");
377MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
378MODULE_LICENSE("GPL");
379
380

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