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/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
  72 struct 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
  81 static 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
 110 static 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
 144 static 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
 165 static 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
 177 static 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
 245 err_irq:
 246         serio_unregister_port(pad_serio);
 247 err_pad:
 248         serio_unregister_port(kb_serio);
 249         return error;
 250 }
 251
 252 static 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
 264 static const struct of_device_id olpc_apsp_dt_ids[] = {
 265         { .compatible = "olpc,ap-sp", },
 266         {}
 267 };
 268 MODULE_DEVICE_TABLE(of, olpc_apsp_dt_ids);
 269
 270 static 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
 279 MODULE_DESCRIPTION("OLPC AP-SP serio driver");
 280 MODULE_LICENSE("GPL");
 281 module_platform_driver(olpc_apsp_driver);