1/*
2 * OLPC serio driver for multiplexed input from Marvell MMP security processor
3 *
4 * Copyright (C) 2011-2013 One Laptop Per Child
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 */
16
17#include <linux/module.h>
18#include <linux/interrupt.h>
19#include <linux/serio.h>
20#include <linux/err.h>
21#include <linux/platform_device.h>
22#include <linux/io.h>
23#include <linux/of.h>
24#include <linux/slab.h>
25#include <linux/delay.h>
26
27/*
28 * The OLPC XO-1.75 and XO-4 laptops do not have a hardware PS/2 controller.
29 * Instead, the OLPC firmware runs a bit-banging PS/2 implementation on an
30 * otherwise-unused slow processor which is included in the Marvell MMP2/MMP3
31 * SoC, known as the "Security Processor" (SP) or "Wireless Trusted Module"
32 * (WTM). This firmware then reports its results via the WTM registers,
33 * which we read from the Application Processor (AP, i.e. main CPU) in this
34 * driver.
35 *
36 * On the hardware side we have a PS/2 mouse and an AT keyboard, the data
37 * is multiplexed through this system. We create a serio port for each one,
38 * and demultiplex the data accordingly.
39 */
40
41/* WTM register offsets */
42#define SECURE_PROCESSOR_COMMAND 0x40
43#define COMMAND_RETURN_STATUS 0x80
44#define COMMAND_FIFO_STATUS 0xc4
45#define PJ_RST_INTERRUPT 0xc8
46#define PJ_INTERRUPT_MASK 0xcc
47
48/*
49 * The upper byte of SECURE_PROCESSOR_COMMAND and COMMAND_RETURN_STATUS is
50 * used to identify which port (device) is being talked to. The lower byte
51 * is the data being sent/received.
52 */
53#define PORT_MASK 0xff00
54#define DATA_MASK 0x00ff
55#define PORT_SHIFT 8
56#define KEYBOARD_PORT 0
57#define TOUCHPAD_PORT 1
58
59/* COMMAND_FIFO_STATUS */
60#define CMD_CNTR_MASK 0x7 /* Number of pending/unprocessed commands */
61#define MAX_PENDING_CMDS 4 /* from device specs */
62
63/* PJ_RST_INTERRUPT */
64#define SP_COMMAND_COMPLETE_RESET 0x1
65
66/* PJ_INTERRUPT_MASK */
67#define INT_0 (1 << 0)
68
69/* COMMAND_FIFO_STATUS */
70#define CMD_STS_MASK 0x100
71
72struct olpc_apsp {
73 struct device *dev;
74 struct serio *kbio;
75 struct serio *padio;
76 void __iomem *base;
77 int open_count;
78 int irq;
79};
80
81static int olpc_apsp_write(struct serio *port, unsigned char val)
82{
83 struct olpc_apsp *priv = port->port_data;
84 unsigned int i;
85 u32 which = 0;
86
87 if (port == priv->padio)
88 which = TOUCHPAD_PORT << PORT_SHIFT;
89 else
90 which = KEYBOARD_PORT << PORT_SHIFT;
91
92 dev_dbg(priv->dev, "olpc_apsp_write which=%x val=%x\n", which, val);
93 for (i = 0; i < 50; i++) {
94 u32 sts = readl(priv->base + COMMAND_FIFO_STATUS);
95 if ((sts & CMD_CNTR_MASK) < MAX_PENDING_CMDS) {
96 writel(which | val,
97 priv->base + SECURE_PROCESSOR_COMMAND);
98 return 0;
99 }
100 /* SP busy. This has not been seen in practice. */
101 mdelay(1);
102 }
103
104 dev_dbg(priv->dev, "olpc_apsp_write timeout, status=%x\n",
105 readl(priv->base + COMMAND_FIFO_STATUS));
106
107 return -ETIMEDOUT;
108}
109
110static irqreturn_t olpc_apsp_rx(int irq, void *dev_id)
111{
112 struct olpc_apsp *priv = dev_id;
113 unsigned int w, tmp;
114 struct serio *serio;
115
116 /*
117 * Write 1 to PJ_RST_INTERRUPT to acknowledge and clear the interrupt
118 * Write 0xff00 to SECURE_PROCESSOR_COMMAND.
119 */
120 tmp = readl(priv->base + PJ_RST_INTERRUPT);
121 if (!(tmp & SP_COMMAND_COMPLETE_RESET)) {
122 dev_warn(priv->dev, "spurious interrupt?\n");
123 return IRQ_NONE;
124 }
125
126 w = readl(priv->base + COMMAND_RETURN_STATUS);
127 dev_dbg(priv->dev, "olpc_apsp_rx %x\n", w);
128
129 if (w >> PORT_SHIFT == KEYBOARD_PORT)
130 serio = priv->kbio;
131 else
132 serio = priv->padio;
133
134 serio_interrupt(serio, w & DATA_MASK, 0);
135
136 /* Ack and clear interrupt */
137 writel(tmp | SP_COMMAND_COMPLETE_RESET, priv->base + PJ_RST_INTERRUPT);
138 writel(PORT_MASK, priv->base + SECURE_PROCESSOR_COMMAND);
139
140 pm_wakeup_event(priv->dev, 1000);
141 return IRQ_HANDLED;
142}
143
144static int olpc_apsp_open(struct serio *port)
145{
146 struct olpc_apsp *priv = port->port_data;
147 unsigned int tmp;
148 unsigned long l;
149
150 if (priv->open_count++ == 0) {
151 l = readl(priv->base + COMMAND_FIFO_STATUS);
152 if (!(l & CMD_STS_MASK)) {
153 dev_err(priv->dev, "SP cannot accept commands.\n");
154 return -EIO;
155 }
156
157 /* Enable interrupt 0 by clearing its bit */
158 tmp = readl(priv->base + PJ_INTERRUPT_MASK);
159 writel(tmp & ~INT_0, priv->base + PJ_INTERRUPT_MASK);
160 }
161
162 return 0;
163}
164
165static void olpc_apsp_close(struct serio *port)
166{
167 struct olpc_apsp *priv = port->port_data;
168 unsigned int tmp;
169
170 if (--priv->open_count == 0) {
171 /* Disable interrupt 0 */
172 tmp = readl(priv->base + PJ_INTERRUPT_MASK);
173 writel(tmp | INT_0, priv->base + PJ_INTERRUPT_MASK);
174 }
175}
176
177static int olpc_apsp_probe(struct platform_device *pdev)
178{
179 struct serio *kb_serio, *pad_serio;
180 struct olpc_apsp *priv;
181 struct resource *res;
182 int error;
183
184 priv = devm_kzalloc(&pdev->dev, sizeof(struct olpc_apsp), GFP_KERNEL);
185 if (!priv)
186 return -ENOMEM;
187
188 priv->dev = &pdev->dev;
189
190 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
191 priv->base = devm_ioremap_resource(&pdev->dev, res);
192 if (IS_ERR(priv->base)) {
193 dev_err(&pdev->dev, "Failed to map WTM registers\n");
194 return PTR_ERR(priv->base);
195 }
196
197 priv->irq = platform_get_irq(pdev, 0);
198 if (priv->irq < 0)
199 return priv->irq;
200
201 /* KEYBOARD */
202 kb_serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
203 if (!kb_serio)
204 return -ENOMEM;
205 kb_serio->id.type = SERIO_8042_XL;
206 kb_serio->write = olpc_apsp_write;
207 kb_serio->open = olpc_apsp_open;
208 kb_serio->close = olpc_apsp_close;
209 kb_serio->port_data = priv;
210 kb_serio->dev.parent = &pdev->dev;
211 strlcpy(kb_serio->name, "sp keyboard", sizeof(kb_serio->name));
212 strlcpy(kb_serio->phys, "sp/serio0", sizeof(kb_serio->phys));
213 priv->kbio = kb_serio;
214 serio_register_port(kb_serio);
215
216 /* TOUCHPAD */
217 pad_serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
218 if (!pad_serio) {
219 error = -ENOMEM;
220 goto err_pad;
221 }
222 pad_serio->id.type = SERIO_8042;
223 pad_serio->write = olpc_apsp_write;
224 pad_serio->open = olpc_apsp_open;
225 pad_serio->close = olpc_apsp_close;
226 pad_serio->port_data = priv;
227 pad_serio->dev.parent = &pdev->dev;
228 strlcpy(pad_serio->name, "sp touchpad", sizeof(pad_serio->name));
229 strlcpy(pad_serio->phys, "sp/serio1", sizeof(pad_serio->phys));
230 priv->padio = pad_serio;
231 serio_register_port(pad_serio);
232
233 error = request_irq(priv->irq, olpc_apsp_rx, 0, "olpc-apsp", priv);
234 if (error) {
235 dev_err(&pdev->dev, "Failed to request IRQ\n");
236 goto err_irq;
237 }
238
239 device_init_wakeup(priv->dev, 1);
240 platform_set_drvdata(pdev, priv);
241
242 dev_dbg(&pdev->dev, "probed successfully.\n");
243 return 0;
244
245err_irq:
246 serio_unregister_port(pad_serio);
247err_pad:
248 serio_unregister_port(kb_serio);
249 return error;
250}
251
252static int olpc_apsp_remove(struct platform_device *pdev)
253{
254 struct olpc_apsp *priv = platform_get_drvdata(pdev);
255
256 free_irq(priv->irq, priv);
257
258 serio_unregister_port(priv->kbio);
259 serio_unregister_port(priv->padio);
260
261 return 0;
262}
263
264static const struct of_device_id olpc_apsp_dt_ids[] = {
265 { .compatible = "olpc,ap-sp", },
266 {}
267};
268MODULE_DEVICE_TABLE(of, olpc_apsp_dt_ids);
269
270static struct platform_driver olpc_apsp_driver = {
271 .probe = olpc_apsp_probe,
272 .remove = olpc_apsp_remove,
273 .driver = {
274 .name = "olpc-apsp",
275 .of_match_table = olpc_apsp_dt_ids,
276 },
277};
278
279MODULE_DESCRIPTION("OLPC AP-SP serio driver");
280MODULE_LICENSE("GPL");
281module_platform_driver(olpc_apsp_driver);
282