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, &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 */
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(&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(drvdata->irq, &xps2_interrupt, 0,
189				DRIVER_NAME, 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, &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 * @ofdev:	pointer to OF device structure
223 *
224 * This function probes the PS/2 device in the device tree.
225 * It initializes the driver data structure and the hardware.
226 * It returns 0, if the driver is bound to the PS/2 device, or a negative
227 * value if there is an error.
228 */
229static int xps2_of_probe(struct platform_device *ofdev)
230{
231	struct resource r_mem; /* IO mem resources */
232	struct xps2data *drvdata;
233	struct serio *serio;
234	struct device *dev = &ofdev->dev;
235	resource_size_t remap_size, phys_addr;
236	unsigned int irq;
237	int error;
238
239	dev_info(dev, "Device Tree Probing \'%pOFn\'\n", dev->of_node);
240
241	/* Get iospace for the device */
242	error = of_address_to_resource(dev->of_node, 0, &r_mem);
243	if (error) {
244		dev_err(dev, "invalid address\n");
245		return error;
246	}
247
248	/* Get IRQ for the device */
249	irq = irq_of_parse_and_map(dev->of_node, 0);
250	if (!irq) {
251		dev_err(dev, "no IRQ found\n");
252		return -ENODEV;
253	}
254
255	drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL);
256	serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
257	if (!drvdata || !serio) {
258		error = -ENOMEM;
259		goto failed1;
260	}
261
262	spin_lock_init(&drvdata->lock);
263	drvdata->irq = irq;
264	drvdata->serio = serio;
265	drvdata->dev = dev;
266
267	phys_addr = r_mem.start;
268	remap_size = resource_size(&r_mem);
269	if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
270		dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
271			(unsigned long long)phys_addr);
272		error = -EBUSY;
273		goto failed1;
274	}
275
276	/* Fill in configuration data and add them to the list */
277	drvdata->base_address = ioremap(phys_addr, remap_size);
278	if (drvdata->base_address == NULL) {
279		dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
280			(unsigned long long)phys_addr);
281		error = -EFAULT;
282		goto failed2;
283	}
284
285	/* Disable all the interrupts, just in case */
286	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);
287
288	/*
289	 * Reset the PS2 device and abort any current transaction,
290	 * to make sure we have the PS2 in a good state.
291	 */
292	out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);
293
294	dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
295		 (unsigned long long)phys_addr, drvdata->base_address,
296		 drvdata->irq);
297
298	serio->id.type = SERIO_8042;
299	serio->write = sxps2_write;
300	serio->open = sxps2_open;
301	serio->close = sxps2_close;
302	serio->port_data = drvdata;
303	serio->dev.parent = dev;
304	snprintf(serio->name, sizeof(serio->name),
305		 "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
306	snprintf(serio->phys, sizeof(serio->phys),
307		 "xilinxps2/serio at %08llX", (unsigned long long)phys_addr);
308
309	serio_register_port(serio);
310
311	platform_set_drvdata(ofdev, drvdata);
312	return 0;		/* success */
313
314failed2:
315	release_mem_region(phys_addr, remap_size);
316failed1:
317	kfree(serio);
318	kfree(drvdata);
319
320	return error;
321}
322
323/**
324 * xps2_of_remove - unbinds the driver from the PS/2 device.
325 * @of_dev:	pointer to OF device structure
326 *
327 * This function is called if a device is physically removed from the system or
328 * if the driver module is being unloaded. It frees any resources allocated to
329 * the device.
330 */
331static void xps2_of_remove(struct platform_device *of_dev)
332{
333	struct xps2data *drvdata = platform_get_drvdata(of_dev);
334	struct resource r_mem; /* IO mem resources */
335
336	serio_unregister_port(drvdata->serio);
337	iounmap(drvdata->base_address);
338
339	/* Get iospace of the device */
340	if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem))
341		dev_err(drvdata->dev, "invalid address\n");
342	else
343		release_mem_region(r_mem.start, resource_size(&r_mem));
344
345	kfree(drvdata);
346}
347
348/* Match table for of_platform binding */
349static const struct of_device_id xps2_of_match[] = {
350	{ .compatible = "xlnx,xps-ps2-1.00.a", },
351	{ /* end of list */ },
352};
353MODULE_DEVICE_TABLE(of, xps2_of_match);
354
355static struct platform_driver xps2_of_driver = {
356	.driver = {
357		.name = DRIVER_NAME,
358		.of_match_table = xps2_of_match,
359	},
360	.probe		= xps2_of_probe,
361	.remove_new	= xps2_of_remove,
362};
363module_platform_driver(xps2_of_driver);
364
365MODULE_AUTHOR("Xilinx, Inc.");
366MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
367MODULE_LICENSE("GPL");
368
369