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
65 struct 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 */
xps2_recv(struct xps2data * drvdata,u8 * byte)86 static 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 /*********************/
xps2_interrupt(int irq,void * dev_id)104 static 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, &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(drvdata->serio, c, 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 */
sxps2_write(struct serio * pserio,unsigned char c)155 static int sxps2_write(struct serio *pserio, unsigned char c)
156 {
157 struct xps2data *drvdata = pserio->port_data;
158 u32 sr;
159
160 guard(spinlock_irqsave)(&drvdata->lock);
161
162 /* If the PS/2 transmitter is empty send a byte of data */
163 sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
164 if (sr & XPS2_STATUS_TX_FULL)
165 return -EAGAIN;
166
167 out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
168 return 0;
169 }
170
171 /**
172 * sxps2_open() - called when a port is opened by the higher layer.
173 * @pserio: pointer to the serio structure of the PS/2 device
174 *
175 * This function requests irq and enables interrupts for the PS/2 device.
176 */
sxps2_open(struct serio * pserio)177 static int sxps2_open(struct serio *pserio)
178 {
179 struct xps2data *drvdata = pserio->port_data;
180 int error;
181 u8 c;
182
183 error = request_irq(drvdata->irq, &xps2_interrupt, 0,
184 DRIVER_NAME, drvdata);
185 if (error) {
186 dev_err(drvdata->dev,
187 "Couldn't allocate interrupt %d\n", drvdata->irq);
188 return error;
189 }
190
191 /* start reception by enabling the interrupts */
192 out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
193 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
194 (void)xps2_recv(drvdata, &c);
195
196 return 0; /* success */
197 }
198
199 /**
200 * sxps2_close() - frees the interrupt.
201 * @pserio: pointer to the serio structure of the PS/2 device
202 *
203 * This function frees the irq and disables interrupts for the PS/2 device.
204 */
sxps2_close(struct serio * pserio)205 static void sxps2_close(struct serio *pserio)
206 {
207 struct xps2data *drvdata = pserio->port_data;
208
209 /* Disable the PS2 interrupts */
210 out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
211 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
212 free_irq(drvdata->irq, drvdata);
213 }
214
215 /**
216 * xps2_of_probe - probe method for the PS/2 device.
217 * @ofdev: pointer to OF device structure
218 *
219 * This function probes the PS/2 device in the device tree.
220 * It initializes the driver data structure and the hardware.
221 * It returns 0, if the driver is bound to the PS/2 device, or a negative
222 * value if there is an error.
223 */
xps2_of_probe(struct platform_device * ofdev)224 static int xps2_of_probe(struct platform_device *ofdev)
225 {
226 struct resource r_mem; /* IO mem resources */
227 struct xps2data *drvdata;
228 struct serio *serio;
229 struct device *dev = &ofdev->dev;
230 resource_size_t remap_size, phys_addr;
231 unsigned int irq;
232 int error;
233
234 dev_info(dev, "Device Tree Probing \'%pOFn\'\n", dev->of_node);
235
236 /* Get iospace for the device */
237 error = of_address_to_resource(dev->of_node, 0, &r_mem);
238 if (error) {
239 dev_err(dev, "invalid address\n");
240 return error;
241 }
242
243 /* Get IRQ for the device */
244 irq = irq_of_parse_and_map(dev->of_node, 0);
245 if (!irq) {
246 dev_err(dev, "no IRQ found\n");
247 return -ENODEV;
248 }
249
250 drvdata = kzalloc(sizeof(*drvdata), GFP_KERNEL);
251 serio = kzalloc(sizeof(*serio), GFP_KERNEL);
252 if (!drvdata || !serio) {
253 error = -ENOMEM;
254 goto failed1;
255 }
256
257 spin_lock_init(&drvdata->lock);
258 drvdata->irq = irq;
259 drvdata->serio = serio;
260 drvdata->dev = dev;
261
262 phys_addr = r_mem.start;
263 remap_size = resource_size(&r_mem);
264 if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
265 dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
266 (unsigned long long)phys_addr);
267 error = -EBUSY;
268 goto failed1;
269 }
270
271 /* Fill in configuration data and add them to the list */
272 drvdata->base_address = ioremap(phys_addr, remap_size);
273 if (drvdata->base_address == NULL) {
274 dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
275 (unsigned long long)phys_addr);
276 error = -EFAULT;
277 goto failed2;
278 }
279
280 /* Disable all the interrupts, just in case */
281 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);
282
283 /*
284 * Reset the PS2 device and abort any current transaction,
285 * to make sure we have the PS2 in a good state.
286 */
287 out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);
288
289 dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
290 (unsigned long long)phys_addr, drvdata->base_address,
291 drvdata->irq);
292
293 serio->id.type = SERIO_8042;
294 serio->write = sxps2_write;
295 serio->open = sxps2_open;
296 serio->close = sxps2_close;
297 serio->port_data = drvdata;
298 serio->dev.parent = dev;
299 snprintf(serio->name, sizeof(serio->name),
300 "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
301 snprintf(serio->phys, sizeof(serio->phys),
302 "xilinxps2/serio at %08llX", (unsigned long long)phys_addr);
303
304 serio_register_port(serio);
305
306 platform_set_drvdata(ofdev, drvdata);
307 return 0; /* success */
308
309 failed2:
310 release_mem_region(phys_addr, remap_size);
311 failed1:
312 kfree(serio);
313 kfree(drvdata);
314
315 return error;
316 }
317
318 /**
319 * xps2_of_remove - unbinds the driver from the PS/2 device.
320 * @of_dev: pointer to OF device structure
321 *
322 * This function is called if a device is physically removed from the system or
323 * if the driver module is being unloaded. It frees any resources allocated to
324 * the device.
325 */
xps2_of_remove(struct platform_device * of_dev)326 static void xps2_of_remove(struct platform_device *of_dev)
327 {
328 struct xps2data *drvdata = platform_get_drvdata(of_dev);
329 struct resource r_mem; /* IO mem resources */
330
331 serio_unregister_port(drvdata->serio);
332 iounmap(drvdata->base_address);
333
334 /* Get iospace of the device */
335 if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem))
336 dev_err(drvdata->dev, "invalid address\n");
337 else
338 release_mem_region(r_mem.start, resource_size(&r_mem));
339
340 kfree(drvdata);
341 }
342
343 /* Match table for of_platform binding */
344 static const struct of_device_id xps2_of_match[] = {
345 { .compatible = "xlnx,xps-ps2-1.00.a", },
346 { /* end of list */ },
347 };
348 MODULE_DEVICE_TABLE(of, xps2_of_match);
349
350 static struct platform_driver xps2_of_driver = {
351 .driver = {
352 .name = DRIVER_NAME,
353 .of_match_table = xps2_of_match,
354 },
355 .probe = xps2_of_probe,
356 .remove = xps2_of_remove,
357 };
358 module_platform_driver(xps2_of_driver);
359
360 MODULE_AUTHOR("Xilinx, Inc.");
361 MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
362 MODULE_LICENSE("GPL");
363
364