1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Xilinx XPS PS/2 device driver
4 *
5 * (c) 2005 MontaVista Software, Inc.
6 * (c) 2008 Xilinx, Inc.
7 */
8
9
10#include <linux/module.h>
11#include <linux/serio.h>
12#include <linux/interrupt.h>
13#include <linux/errno.h>
14#include <linux/slab.h>
15#include <linux/list.h>
16#include <linux/io.h>
17#include <linux/mod_devicetable.h>
18#include <linux/of_address.h>
19#include <linux/of_irq.h>
20#include <linux/platform_device.h>
21
22#define DRIVER_NAME "xilinx_ps2"
23
24/* Register offsets for the xps2 device */
25#define XPS2_SRST_OFFSET 0x00000000 /* Software Reset register */
26#define XPS2_STATUS_OFFSET 0x00000004 /* Status register */
27#define XPS2_RX_DATA_OFFSET 0x00000008 /* Receive Data register */
28#define XPS2_TX_DATA_OFFSET 0x0000000C /* Transmit Data register */
29#define XPS2_GIER_OFFSET 0x0000002C /* Global Interrupt Enable reg */
30#define XPS2_IPISR_OFFSET 0x00000030 /* Interrupt Status register */
31#define XPS2_IPIER_OFFSET 0x00000038 /* Interrupt Enable register */
32
33/* Reset Register Bit Definitions */
34#define XPS2_SRST_RESET 0x0000000A /* Software Reset */
35
36/* Status Register Bit Positions */
37#define XPS2_STATUS_RX_FULL 0x00000001 /* Receive Full */
38#define XPS2_STATUS_TX_FULL 0x00000002 /* Transmit Full */
39
40/*
41 * Bit definitions for ISR/IER registers. Both the registers have the same bit
42 * definitions and are only defined once.
43 */
44#define XPS2_IPIXR_WDT_TOUT 0x00000001 /* Watchdog Timeout Interrupt */
45#define XPS2_IPIXR_TX_NOACK 0x00000002 /* Transmit No ACK Interrupt */
46#define XPS2_IPIXR_TX_ACK 0x00000004 /* Transmit ACK (Data) Interrupt */
47#define XPS2_IPIXR_RX_OVF 0x00000008 /* Receive Overflow Interrupt */
48#define XPS2_IPIXR_RX_ERR 0x00000010 /* Receive Error Interrupt */
49#define XPS2_IPIXR_RX_FULL 0x00000020 /* Receive Data Interrupt */
50
51/* Mask for all the Transmit Interrupts */
52#define XPS2_IPIXR_TX_ALL (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_TX_ACK)
53
54/* Mask for all the Receive Interrupts */
55#define XPS2_IPIXR_RX_ALL (XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR | \
56 XPS2_IPIXR_RX_FULL)
57
58/* Mask for all the Interrupts */
59#define XPS2_IPIXR_ALL (XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL | \
60 XPS2_IPIXR_WDT_TOUT)
61
62/* Global Interrupt Enable mask */
63#define XPS2_GIER_GIE_MASK 0x80000000
64
65struct xps2data {
66 int irq;
67 spinlock_t lock;
68 void __iomem *base_address; /* virt. address of control registers */
69 unsigned int flags;
70 struct serio *serio; /* serio */
71 struct device *dev;
72};
73
74/************************************/
75/* XPS PS/2 data transmission calls */
76/************************************/
77
78/**
79 * xps2_recv() - attempts to receive a byte from the PS/2 port.
80 * @drvdata: pointer to ps2 device private data structure
81 * @byte: address where the read data will be copied
82 *
83 * If there is any data available in the PS/2 receiver, this functions reads
84 * the data, otherwise it returns error.
85 */
86static int xps2_recv(struct xps2data *drvdata, u8 *byte)
87{
88 u32 sr;
89 int status = -1;
90
91 /* If there is data available in the PS/2 receiver, read it */
92 sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
93 if (sr & XPS2_STATUS_RX_FULL) {
94 *byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET);
95 status = 0;
96 }
97
98 return status;
99}
100
101/*********************/
102/* Interrupt handler */
103/*********************/
104static irqreturn_t xps2_interrupt(int irq, void *dev_id)
105{
106 struct xps2data *drvdata = dev_id;
107 u32 intr_sr;
108 u8 c;
109 int status;
110
111 /* Get the PS/2 interrupts and clear them */
112 intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET);
113 out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);
114
115 /* Check which interrupt is active */
116 if (intr_sr & XPS2_IPIXR_RX_OVF)
117 dev_warn(drvdata->dev, "receive overrun error\n");
118
119 if (intr_sr & XPS2_IPIXR_RX_ERR)
120 drvdata->flags |= SERIO_PARITY;
121
122 if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
123 drvdata->flags |= SERIO_TIMEOUT;
124
125 if (intr_sr & XPS2_IPIXR_RX_FULL) {
126 status = xps2_recv(drvdata, byte: &c);
127
128 /* Error, if a byte is not received */
129 if (status) {
130 dev_err(drvdata->dev,
131 "wrong rcvd byte count (%d)\n", status);
132 } else {
133 serio_interrupt(serio: drvdata->serio, data: c, flags: drvdata->flags);
134 drvdata->flags = 0;
135 }
136 }
137
138 return IRQ_HANDLED;
139}
140
141/*******************/
142/* serio callbacks */
143/*******************/
144
145/**
146 * sxps2_write() - sends a byte out through the PS/2 port.
147 * @pserio: pointer to the serio structure of the PS/2 port
148 * @c: data that needs to be written to the PS/2 port
149 *
150 * This function checks if the PS/2 transmitter is empty and sends a byte.
151 * Otherwise it returns error. Transmission fails only when nothing is connected
152 * to the PS/2 port. Thats why, we do not try to resend the data in case of a
153 * failure.
154 */
155static int sxps2_write(struct serio *pserio, unsigned char c)
156{
157 struct xps2data *drvdata = pserio->port_data;
158 unsigned long flags;
159 u32 sr;
160 int status = -1;
161
162 spin_lock_irqsave(&drvdata->lock, flags);
163
164 /* If the PS/2 transmitter is empty send a byte of data */
165 sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
166 if (!(sr & XPS2_STATUS_TX_FULL)) {
167 out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
168 status = 0;
169 }
170
171 spin_unlock_irqrestore(lock: &drvdata->lock, flags);
172
173 return status;
174}
175
176/**
177 * sxps2_open() - called when a port is opened by the higher layer.
178 * @pserio: pointer to the serio structure of the PS/2 device
179 *
180 * This function requests irq and enables interrupts for the PS/2 device.
181 */
182static int sxps2_open(struct serio *pserio)
183{
184 struct xps2data *drvdata = pserio->port_data;
185 int error;
186 u8 c;
187
188 error = request_irq(irq: drvdata->irq, handler: &xps2_interrupt, flags: 0,
189 DRIVER_NAME, dev: drvdata);
190 if (error) {
191 dev_err(drvdata->dev,
192 "Couldn't allocate interrupt %d\n", drvdata->irq);
193 return error;
194 }
195
196 /* start reception by enabling the interrupts */
197 out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
198 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
199 (void)xps2_recv(drvdata, byte: &c);
200
201 return 0; /* success */
202}
203
204/**
205 * sxps2_close() - frees the interrupt.
206 * @pserio: pointer to the serio structure of the PS/2 device
207 *
208 * This function frees the irq and disables interrupts for the PS/2 device.
209 */
210static void sxps2_close(struct serio *pserio)
211{
212 struct xps2data *drvdata = pserio->port_data;
213
214 /* Disable the PS2 interrupts */
215 out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
216 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
217 free_irq(drvdata->irq, drvdata);
218}
219
220/**
221 * xps2_of_probe - probe method for the PS/2 device.
222 * @of_dev: pointer to OF device structure
223 * @match: pointer to the structure used for matching a device
224 *
225 * This function probes the PS/2 device in the device tree.
226 * It initializes the driver data structure and the hardware.
227 * It returns 0, if the driver is bound to the PS/2 device, or a negative
228 * value if there is an error.
229 */
230static int xps2_of_probe(struct platform_device *ofdev)
231{
232 struct resource r_mem; /* IO mem resources */
233 struct xps2data *drvdata;
234 struct serio *serio;
235 struct device *dev = &ofdev->dev;
236 resource_size_t remap_size, phys_addr;
237 unsigned int irq;
238 int error;
239
240 dev_info(dev, "Device Tree Probing \'%pOFn\'\n", dev->of_node);
241
242 /* Get iospace for the device */
243 error = of_address_to_resource(dev: dev->of_node, index: 0, r: &r_mem);
244 if (error) {
245 dev_err(dev, "invalid address\n");
246 return error;
247 }
248
249 /* Get IRQ for the device */
250 irq = irq_of_parse_and_map(node: dev->of_node, index: 0);
251 if (!irq) {
252 dev_err(dev, "no IRQ found\n");
253 return -ENODEV;
254 }
255
256 drvdata = kzalloc(size: sizeof(struct xps2data), GFP_KERNEL);
257 serio = kzalloc(size: sizeof(struct serio), GFP_KERNEL);
258 if (!drvdata || !serio) {
259 error = -ENOMEM;
260 goto failed1;
261 }
262
263 spin_lock_init(&drvdata->lock);
264 drvdata->irq = irq;
265 drvdata->serio = serio;
266 drvdata->dev = dev;
267
268 phys_addr = r_mem.start;
269 remap_size = resource_size(res: &r_mem);
270 if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
271 dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
272 (unsigned long long)phys_addr);
273 error = -EBUSY;
274 goto failed1;
275 }
276
277 /* Fill in configuration data and add them to the list */
278 drvdata->base_address = ioremap(offset: phys_addr, size: remap_size);
279 if (drvdata->base_address == NULL) {
280 dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
281 (unsigned long long)phys_addr);
282 error = -EFAULT;
283 goto failed2;
284 }
285
286 /* Disable all the interrupts, just in case */
287 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);
288
289 /*
290 * Reset the PS2 device and abort any current transaction,
291 * to make sure we have the PS2 in a good state.
292 */
293 out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);
294
295 dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
296 (unsigned long long)phys_addr, drvdata->base_address,
297 drvdata->irq);
298
299 serio->id.type = SERIO_8042;
300 serio->write = sxps2_write;
301 serio->open = sxps2_open;
302 serio->close = sxps2_close;
303 serio->port_data = drvdata;
304 serio->dev.parent = dev;
305 snprintf(buf: serio->name, size: sizeof(serio->name),
306 fmt: "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
307 snprintf(buf: serio->phys, size: sizeof(serio->phys),
308 fmt: "xilinxps2/serio at %08llX", (unsigned long long)phys_addr);
309
310 serio_register_port(serio);
311
312 platform_set_drvdata(pdev: ofdev, data: drvdata);
313 return 0; /* success */
314
315failed2:
316 release_mem_region(phys_addr, remap_size);
317failed1:
318 kfree(objp: serio);
319 kfree(objp: drvdata);
320
321 return error;
322}
323
324/**
325 * xps2_of_remove - unbinds the driver from the PS/2 device.
326 * @of_dev: pointer to OF device structure
327 *
328 * This function is called if a device is physically removed from the system or
329 * if the driver module is being unloaded. It frees any resources allocated to
330 * the device.
331 */
332static int xps2_of_remove(struct platform_device *of_dev)
333{
334 struct xps2data *drvdata = platform_get_drvdata(pdev: of_dev);
335 struct resource r_mem; /* IO mem resources */
336
337 serio_unregister_port(serio: drvdata->serio);
338 iounmap(addr: drvdata->base_address);
339
340 /* Get iospace of the device */
341 if (of_address_to_resource(dev: of_dev->dev.of_node, index: 0, r: &r_mem))
342 dev_err(drvdata->dev, "invalid address\n");
343 else
344 release_mem_region(r_mem.start, resource_size(&r_mem));
345
346 kfree(objp: drvdata);
347
348 return 0;
349}
350
351/* Match table for of_platform binding */
352static const struct of_device_id xps2_of_match[] = {
353 { .compatible = "xlnx,xps-ps2-1.00.a", },
354 { /* end of list */ },
355};
356MODULE_DEVICE_TABLE(of, xps2_of_match);
357
358static struct platform_driver xps2_of_driver = {
359 .driver = {
360 .name = DRIVER_NAME,
361 .of_match_table = xps2_of_match,
362 },
363 .probe = xps2_of_probe,
364 .remove = xps2_of_remove,
365};
366module_platform_driver(xps2_of_driver);
367
368MODULE_AUTHOR("Xilinx, Inc.");
369MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
370MODULE_LICENSE("GPL");
371
372

source code of linux/drivers/input/serio/xilinx_ps2.c