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 | */ |
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 | /*********************/ |
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, 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 | */ |
155 | static 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 | */ |
182 | static 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 | */ |
210 | static 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 | */ |
230 | static 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 | |
315 | failed2: |
316 | release_mem_region(phys_addr, remap_size); |
317 | failed1: |
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 | */ |
332 | static 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 */ |
352 | static const struct of_device_id xps2_of_match[] = { |
353 | { .compatible = "xlnx,xps-ps2-1.00.a" , }, |
354 | { /* end of list */ }, |
355 | }; |
356 | MODULE_DEVICE_TABLE(of, xps2_of_match); |
357 | |
358 | static 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 | }; |
366 | module_platform_driver(xps2_of_driver); |
367 | |
368 | MODULE_AUTHOR("Xilinx, Inc." ); |
369 | MODULE_DESCRIPTION("Xilinx XPS PS/2 driver" ); |
370 | MODULE_LICENSE("GPL" ); |
371 | |
372 | |