2 * OLPC serio driver for multiplexed input from Marvell MMP security processor
4 * Copyright (C) 2011-2013 One Laptop Per Child
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.
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.
17 #include <linux/module.h>
18 #include <linux/interrupt.h>
19 #include <linux/init.h>
20 #include <linux/serio.h>
21 #include <linux/err.h>
22 #include <linux/platform_device.h>
25 #include <linux/slab.h>
26 #include <linux/delay.h>
29 * The OLPC XO-1.75 and XO-4 laptops do not have a hardware PS/2 controller.
30 * Instead, the OLPC firmware runs a bit-banging PS/2 implementation on an
31 * otherwise-unused slow processor which is included in the Marvell MMP2/MMP3
32 * SoC, known as the "Security Processor" (SP) or "Wireless Trusted Module"
33 * (WTM). This firmware then reports its results via the WTM registers,
34 * which we read from the Application Processor (AP, i.e. main CPU) in this
37 * On the hardware side we have a PS/2 mouse and an AT keyboard, the data
38 * is multiplexed through this system. We create a serio port for each one,
39 * and demultiplex the data accordingly.
42 /* WTM register offsets */
43 #define SECURE_PROCESSOR_COMMAND 0x40
44 #define COMMAND_RETURN_STATUS 0x80
45 #define COMMAND_FIFO_STATUS 0xc4
46 #define PJ_RST_INTERRUPT 0xc8
47 #define PJ_INTERRUPT_MASK 0xcc
50 * The upper byte of SECURE_PROCESSOR_COMMAND and COMMAND_RETURN_STATUS is
51 * used to identify which port (device) is being talked to. The lower byte
52 * is the data being sent/received.
54 #define PORT_MASK 0xff00
55 #define DATA_MASK 0x00ff
57 #define KEYBOARD_PORT 0
58 #define TOUCHPAD_PORT 1
60 /* COMMAND_FIFO_STATUS */
61 #define CMD_CNTR_MASK 0x7 /* Number of pending/unprocessed commands */
62 #define MAX_PENDING_CMDS 4 /* from device specs */
64 /* PJ_RST_INTERRUPT */
65 #define SP_COMMAND_COMPLETE_RESET 0x1
67 /* PJ_INTERRUPT_MASK */
68 #define INT_0 (1 << 0)
70 /* COMMAND_FIFO_STATUS */
71 #define CMD_STS_MASK 0x100
82 static int olpc_apsp_write(struct serio *port, unsigned char val)
84 struct olpc_apsp *priv = port->port_data;
88 if (port == priv->padio)
89 which = TOUCHPAD_PORT << PORT_SHIFT;
91 which = KEYBOARD_PORT << PORT_SHIFT;
93 dev_dbg(priv->dev, "olpc_apsp_write which=%x val=%x\n", which, val);
94 for (i = 0; i < 50; i++) {
95 u32 sts = readl(priv->base + COMMAND_FIFO_STATUS);
96 if ((sts & CMD_CNTR_MASK) < MAX_PENDING_CMDS) {
98 priv->base + SECURE_PROCESSOR_COMMAND);
101 /* SP busy. This has not been seen in practice. */
105 dev_dbg(priv->dev, "olpc_apsp_write timeout, status=%x\n",
106 readl(priv->base + COMMAND_FIFO_STATUS));
111 static irqreturn_t olpc_apsp_rx(int irq, void *dev_id)
113 struct olpc_apsp *priv = dev_id;
118 * Write 1 to PJ_RST_INTERRUPT to acknowledge and clear the interrupt
119 * Write 0xff00 to SECURE_PROCESSOR_COMMAND.
121 tmp = readl(priv->base + PJ_RST_INTERRUPT);
122 if (!(tmp & SP_COMMAND_COMPLETE_RESET)) {
123 dev_warn(priv->dev, "spurious interrupt?\n");
127 w = readl(priv->base + COMMAND_RETURN_STATUS);
128 dev_dbg(priv->dev, "olpc_apsp_rx %x\n", w);
130 if (w >> PORT_SHIFT == KEYBOARD_PORT)
135 serio_interrupt(serio, w & DATA_MASK, 0);
137 /* Ack and clear interrupt */
138 writel(tmp | SP_COMMAND_COMPLETE_RESET, priv->base + PJ_RST_INTERRUPT);
139 writel(PORT_MASK, priv->base + SECURE_PROCESSOR_COMMAND);
141 pm_wakeup_event(priv->dev, 1000);
145 static int olpc_apsp_open(struct serio *port)
147 struct olpc_apsp *priv = port->port_data;
150 if (priv->open_count++ == 0) {
151 /* Enable interrupt 0 by clearing its bit */
152 tmp = readl(priv->base + PJ_INTERRUPT_MASK);
153 writel(tmp & ~INT_0, priv->base + PJ_INTERRUPT_MASK);
159 static void olpc_apsp_close(struct serio *port)
161 struct olpc_apsp *priv = port->port_data;
164 if (--priv->open_count == 0) {
165 /* Disable interrupt 0 */
166 tmp = readl(priv->base + PJ_INTERRUPT_MASK);
167 writel(tmp | INT_0, priv->base + PJ_INTERRUPT_MASK);
171 static int olpc_apsp_probe(struct platform_device *pdev)
173 struct serio *kb_serio, *pad_serio;
174 struct olpc_apsp *priv;
175 struct resource *res;
176 struct device_node *np;
180 priv = devm_kzalloc(&pdev->dev, sizeof(struct olpc_apsp), GFP_KERNEL);
184 np = pdev->dev.of_node;
185 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
189 priv->base = devm_ioremap_resource(&pdev->dev, res);
190 if (IS_ERR(priv->base)) {
191 dev_err(&pdev->dev, "Failed to map WTM registers\n");
192 return PTR_ERR(priv->base);
195 priv->irq = platform_get_irq(pdev, 0);
199 l = readl(priv->base + COMMAND_FIFO_STATUS);
200 if (!(l & CMD_STS_MASK)) {
201 dev_err(&pdev->dev, "SP cannot accept commands.\n");
206 kb_serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
209 kb_serio->id.type = SERIO_8042_XL;
210 kb_serio->write = olpc_apsp_write;
211 kb_serio->open = olpc_apsp_open;
212 kb_serio->close = olpc_apsp_close;
213 kb_serio->port_data = priv;
214 kb_serio->dev.parent = &pdev->dev;
215 strlcpy(kb_serio->name, "sp keyboard", sizeof(kb_serio->name));
216 strlcpy(kb_serio->phys, "sp/serio0", sizeof(kb_serio->phys));
217 priv->kbio = kb_serio;
218 serio_register_port(kb_serio);
221 pad_serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
226 pad_serio->id.type = SERIO_8042;
227 pad_serio->write = olpc_apsp_write;
228 pad_serio->open = olpc_apsp_open;
229 pad_serio->close = olpc_apsp_close;
230 pad_serio->port_data = priv;
231 pad_serio->dev.parent = &pdev->dev;
232 strlcpy(pad_serio->name, "sp touchpad", sizeof(pad_serio->name));
233 strlcpy(pad_serio->phys, "sp/serio1", sizeof(pad_serio->phys));
234 priv->padio = pad_serio;
235 serio_register_port(pad_serio);
237 error = request_irq(priv->irq, olpc_apsp_rx, 0, "olpc-apsp", priv);
239 dev_err(&pdev->dev, "Failed to request IRQ\n");
243 priv->dev = &pdev->dev;
244 device_init_wakeup(priv->dev, 1);
245 platform_set_drvdata(pdev, priv);
247 dev_dbg(&pdev->dev, "probed successfully.\n");
251 serio_unregister_port(pad_serio);
253 serio_unregister_port(kb_serio);
257 static int olpc_apsp_remove(struct platform_device *pdev)
259 struct olpc_apsp *priv = platform_get_drvdata(pdev);
261 free_irq(priv->irq, priv);
263 serio_unregister_port(priv->kbio);
264 serio_unregister_port(priv->padio);
269 static struct of_device_id olpc_apsp_dt_ids[] = {
270 { .compatible = "olpc,ap-sp", },
273 MODULE_DEVICE_TABLE(of, olpc_apsp_dt_ids);
275 static struct platform_driver olpc_apsp_driver = {
276 .probe = olpc_apsp_probe,
277 .remove = olpc_apsp_remove,
280 .owner = THIS_MODULE,
281 .of_match_table = olpc_apsp_dt_ids,
285 MODULE_DESCRIPTION("OLPC AP-SP serio driver");
286 MODULE_LICENSE("GPL");
287 module_platform_driver(olpc_apsp_driver);