drivers/input/serio/olpc_apsp.c

   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/init.h>
  20 #include <linux/serio.h>
  21 #include <linux/err.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/io.h>
  24 #include <linux/of.h>
  25 #include <linux/slab.h>
  26 #include <linux/delay.h>
  27
  28 /*
  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
  35  * driver.
  36  *
  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.
  40  */
  41
  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
  48
  49 /*
  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.
  53  */
  54 #define PORT_MASK       0xff00
  55 #define DATA_MASK       0x00ff
  56 #define PORT_SHIFT      8
  57 #define KEYBOARD_PORT   0
  58 #define TOUCHPAD_PORT   1
  59
  60 /* COMMAND_FIFO_STATUS */
  61 #define CMD_CNTR_MASK           0x7 /* Number of pending/unprocessed commands */
  62 #define MAX_PENDING_CMDS        4   /* from device specs */
  63
  64 /* PJ_RST_INTERRUPT */
  65 #define SP_COMMAND_COMPLETE_RESET       0x1
  66
  67 /* PJ_INTERRUPT_MASK */
  68 #define INT_0   (1 << 0)
  69
  70 /* COMMAND_FIFO_STATUS */
  71 #define CMD_STS_MASK    0x100
  72
  73 struct olpc_apsp {
  74         struct device *dev;
  75         struct serio *kbio;
  76         struct serio *padio;
  77         void __iomem *base;
  78         int open_count;
  79         int irq;
  80 };
  81
  82 static int olpc_apsp_write(struct serio *port, unsigned char val)
  83 {
  84         struct olpc_apsp *priv = port->port_data;
  85         unsigned int i;
  86         u32 which = 0;
  87
  88         if (port == priv->padio)
  89                 which = TOUCHPAD_PORT << PORT_SHIFT;
  90         else
  91                 which = KEYBOARD_PORT << PORT_SHIFT;
  92
  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) {
  97                         writel(which | val,
  98                                priv->base + SECURE_PROCESSOR_COMMAND);
  99                         return 0;
 100                 }
 101                 /* SP busy. This has not been seen in practice. */
 102                 mdelay(1);
 103         }
 104
 105         dev_dbg(priv->dev, "olpc_apsp_write timeout, status=%x\n",
 106                 readl(priv->base + COMMAND_FIFO_STATUS));
 107
 108         return -ETIMEDOUT;
 109 }
 110
 111 static irqreturn_t olpc_apsp_rx(int irq, void *dev_id)
 112 {
 113         struct olpc_apsp *priv = dev_id;
 114         unsigned int w, tmp;
 115         struct serio *serio;
 116
 117         /*
 118          * Write 1 to PJ_RST_INTERRUPT to acknowledge and clear the interrupt
 119          * Write 0xff00 to SECURE_PROCESSOR_COMMAND.
 120          */
 121         tmp = readl(priv->base + PJ_RST_INTERRUPT);
 122         if (!(tmp & SP_COMMAND_COMPLETE_RESET)) {
 123                 dev_warn(priv->dev, "spurious interrupt?\n");
 124                 return IRQ_NONE;
 125         }
 126
 127         w = readl(priv->base + COMMAND_RETURN_STATUS);
 128         dev_dbg(priv->dev, "olpc_apsp_rx %x\n", w);
 129
 130         if (w >> PORT_SHIFT == KEYBOARD_PORT)
 131                 serio = priv->kbio;
 132         else
 133                 serio = priv->padio;
 134
 135         serio_interrupt(serio, w & DATA_MASK, 0);
 136
 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);
 140
 141         pm_wakeup_event(priv->dev, 1000);
 142         return IRQ_HANDLED;
 143 }
 144
 145 static int olpc_apsp_open(struct serio *port)
 146 {
 147         struct olpc_apsp *priv = port->port_data;
 148         unsigned int tmp;
 149
 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);
 154         }
 155
 156         return 0;
 157 }
 158
 159 static void olpc_apsp_close(struct serio *port)
 160 {
 161         struct olpc_apsp *priv = port->port_data;
 162         unsigned int tmp;
 163
 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);
 168         }
 169 }
 170
 171 static int olpc_apsp_probe(struct platform_device *pdev)
 172 {
 173         struct serio *kb_serio, *pad_serio;
 174         struct olpc_apsp *priv;
 175         struct resource *res;
 176         struct device_node *np;
 177         unsigned long l;
 178         int error;
 179
 180         priv = devm_kzalloc(&pdev->dev, sizeof(struct olpc_apsp), GFP_KERNEL);
 181         if (!priv)
 182                 return -ENOMEM;
 183
 184         np = pdev->dev.of_node;
 185         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 186         priv->base = devm_ioremap_resource(&pdev->dev, res);
 187         if (IS_ERR(priv->base)) {
 188                 dev_err(&pdev->dev, "Failed to map WTM registers\n");
 189                 return PTR_ERR(priv->base);
 190         }
 191
 192         priv->irq = platform_get_irq(pdev, 0);
 193         if (priv->irq < 0)
 194                 return priv->irq;
 195
 196         l = readl(priv->base + COMMAND_FIFO_STATUS);
 197         if (!(l & CMD_STS_MASK)) {
 198                 dev_err(&pdev->dev, "SP cannot accept commands.\n");
 199                 return -EIO;
 200         }
 201
 202         /* KEYBOARD */
 203         kb_serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
 204         if (!kb_serio)
 205                 return -ENOMEM;
 206         kb_serio->id.type       = SERIO_8042_XL;
 207         kb_serio->write         = olpc_apsp_write;
 208         kb_serio->open          = olpc_apsp_open;
 209         kb_serio->close         = olpc_apsp_close;
 210         kb_serio->port_data     = priv;
 211         kb_serio->dev.parent    = &pdev->dev;
 212         strlcpy(kb_serio->name, "sp keyboard", sizeof(kb_serio->name));
 213         strlcpy(kb_serio->phys, "sp/serio0", sizeof(kb_serio->phys));
 214         priv->kbio              = kb_serio;
 215         serio_register_port(kb_serio);
 216
 217         /* TOUCHPAD */
 218         pad_serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
 219         if (!pad_serio) {
 220                 error = -ENOMEM;
 221                 goto err_pad;
 222         }
 223         pad_serio->id.type      = SERIO_8042;
 224         pad_serio->write        = olpc_apsp_write;
 225         pad_serio->open         = olpc_apsp_open;
 226         pad_serio->close        = olpc_apsp_close;
 227         pad_serio->port_data    = priv;
 228         pad_serio->dev.parent   = &pdev->dev;
 229         strlcpy(pad_serio->name, "sp touchpad", sizeof(pad_serio->name));
 230         strlcpy(pad_serio->phys, "sp/serio1", sizeof(pad_serio->phys));
 231         priv->padio             = pad_serio;
 232         serio_register_port(pad_serio);
 233
 234         error = request_irq(priv->irq, olpc_apsp_rx, 0, "olpc-apsp", priv);
 235         if (error) {
 236                 dev_err(&pdev->dev, "Failed to request IRQ\n");
 237                 goto err_irq;
 238         }
 239
 240         priv->dev = &pdev->dev;
 241         device_init_wakeup(priv->dev, 1);
 242         platform_set_drvdata(pdev, priv);
 243
 244         dev_dbg(&pdev->dev, "probed successfully.\n");
 245         return 0;
 246
 247 err_irq:
 248         serio_unregister_port(pad_serio);
 249 err_pad:
 250         serio_unregister_port(kb_serio);
 251         return error;
 252 }
 253
 254 static int olpc_apsp_remove(struct platform_device *pdev)
 255 {
 256         struct olpc_apsp *priv = platform_get_drvdata(pdev);
 257
 258         free_irq(priv->irq, priv);
 259
 260         serio_unregister_port(priv->kbio);
 261         serio_unregister_port(priv->padio);
 262
 263         return 0;
 264 }
 265
 266 static struct of_device_id olpc_apsp_dt_ids[] = {
 267         { .compatible = "olpc,ap-sp", },
 268         {}
 269 };
 270 MODULE_DEVICE_TABLE(of, olpc_apsp_dt_ids);
 271
 272 static struct platform_driver olpc_apsp_driver = {
 273         .probe          = olpc_apsp_probe,
 274         .remove         = olpc_apsp_remove,
 275         .driver         = {
 276                 .name   = "olpc-apsp",
 277                 .owner  = THIS_MODULE,
 278                 .of_match_table = olpc_apsp_dt_ids,
 279         },
 280 };
 281
 282 MODULE_DESCRIPTION("OLPC AP-SP serio driver");
 283 MODULE_LICENSE("GPL");
 284 module_platform_driver(olpc_apsp_driver);