LXR linux/drivers/input/serio/olpc

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * OLPC serio driver for multiplexed input from Marvell MMP security processor
   4 *
   5 * Copyright (C) 2011-2013 One Laptop Per Child
   6 */
   7
   8#include <linux/module.h>
   9#include <linux/interrupt.h>
  10#include <linux/serio.h>
  11#include <linux/err.h>
  12#include <linux/platform_device.h>
  13#include <linux/io.h>
  14#include <linux/of.h>
  15#include <linux/slab.h>
  16#include <linux/delay.h>
  17
  18/*
  19 * The OLPC XO-1.75 and XO-4 laptops do not have a hardware PS/2 controller.
  20 * Instead, the OLPC firmware runs a bit-banging PS/2 implementation on an
  21 * otherwise-unused slow processor which is included in the Marvell MMP2/MMP3
  22 * SoC, known as the "Security Processor" (SP) or "Wireless Trusted Module"
  23 * (WTM). This firmware then reports its results via the WTM registers,
  24 * which we read from the Application Processor (AP, i.e. main CPU) in this
  25 * driver.
  26 *
  27 * On the hardware side we have a PS/2 mouse and an AT keyboard, the data
  28 * is multiplexed through this system. We create a serio port for each one,
  29 * and demultiplex the data accordingly.
  30 */
  31
  32/* WTM register offsets */
  33#define SECURE_PROCESSOR_COMMAND        0x40
  34#define COMMAND_RETURN_STATUS           0x80
  35#define COMMAND_FIFO_STATUS             0xc4
  36#define PJ_RST_INTERRUPT                0xc8
  37#define PJ_INTERRUPT_MASK               0xcc
  38
  39/*
  40 * The upper byte of SECURE_PROCESSOR_COMMAND and COMMAND_RETURN_STATUS is
  41 * used to identify which port (device) is being talked to. The lower byte
  42 * is the data being sent/received.
  43 */
  44#define PORT_MASK       0xff00
  45#define DATA_MASK       0x00ff
  46#define PORT_SHIFT      8
  47#define KEYBOARD_PORT   0
  48#define TOUCHPAD_PORT   1
  49
  50/* COMMAND_FIFO_STATUS */
  51#define CMD_CNTR_MASK           0x7 /* Number of pending/unprocessed commands */
  52#define MAX_PENDING_CMDS        4   /* from device specs */
  53
  54/* PJ_RST_INTERRUPT */
  55#define SP_COMMAND_COMPLETE_RESET       0x1
  56
  57/* PJ_INTERRUPT_MASK */
  58#define INT_0   (1 << 0)
  59
  60/* COMMAND_FIFO_STATUS */
  61#define CMD_STS_MASK    0x100
  62
  63struct olpc_apsp {
  64        struct device *dev;
  65        struct serio *kbio;
  66        struct serio *padio;
  67        void __iomem *base;
  68        int open_count;
  69        int irq;
  70};
  71
  72static int olpc_apsp_write(struct serio *port, unsigned char val)
  73{
  74        struct olpc_apsp *priv = port->port_data;
  75        unsigned int i;
  76        u32 which = 0;
  77
  78        if (port == priv->padio)
  79                which = TOUCHPAD_PORT << PORT_SHIFT;
  80        else
  81                which = KEYBOARD_PORT << PORT_SHIFT;
  82
  83        dev_dbg(priv->dev, "olpc_apsp_write which=%x val=%x\n", which, val);
  84        for (i = 0; i < 50; i++) {
  85                u32 sts = readl(priv->base + COMMAND_FIFO_STATUS);
  86                if ((sts & CMD_CNTR_MASK) < MAX_PENDING_CMDS) {
  87                        writel(which | val,
  88                               priv->base + SECURE_PROCESSOR_COMMAND);
  89                        return 0;
  90                }
  91                /* SP busy. This has not been seen in practice. */
  92                mdelay(1);
  93        }
  94
  95        dev_dbg(priv->dev, "olpc_apsp_write timeout, status=%x\n",
  96                readl(priv->base + COMMAND_FIFO_STATUS));
  97
  98        return -ETIMEDOUT;
  99}
 100
 101static irqreturn_t olpc_apsp_rx(int irq, void *dev_id)
 102{
 103        struct olpc_apsp *priv = dev_id;
 104        unsigned int w, tmp;
 105        struct serio *serio;
 106
 107        /*
 108         * Write 1 to PJ_RST_INTERRUPT to acknowledge and clear the interrupt
 109         * Write 0xff00 to SECURE_PROCESSOR_COMMAND.
 110         */
 111        tmp = readl(priv->base + PJ_RST_INTERRUPT);
 112        if (!(tmp & SP_COMMAND_COMPLETE_RESET)) {
 113                dev_warn(priv->dev, "spurious interrupt?\n");
 114                return IRQ_NONE;
 115        }
 116
 117        w = readl(priv->base + COMMAND_RETURN_STATUS);
 118        dev_dbg(priv->dev, "olpc_apsp_rx %x\n", w);
 119
 120        if (w >> PORT_SHIFT == KEYBOARD_PORT)
 121                serio = priv->kbio;
 122        else
 123                serio = priv->padio;
 124
 125        serio_interrupt(serio, w & DATA_MASK, 0);
 126
 127        /* Ack and clear interrupt */
 128        writel(tmp | SP_COMMAND_COMPLETE_RESET, priv->base + PJ_RST_INTERRUPT);
 129        writel(PORT_MASK, priv->base + SECURE_PROCESSOR_COMMAND);
 130
 131        pm_wakeup_event(priv->dev, 1000);
 132        return IRQ_HANDLED;
 133}
 134
 135static int olpc_apsp_open(struct serio *port)
 136{
 137        struct olpc_apsp *priv = port->port_data;
 138        unsigned int tmp;
 139        unsigned long l;
 140
 141        if (priv->open_count++ == 0) {
 142                l = readl(priv->base + COMMAND_FIFO_STATUS);
 143                if (!(l & CMD_STS_MASK)) {
 144                        dev_err(priv->dev, "SP cannot accept commands.\n");
 145                        return -EIO;
 146                }
 147
 148                /* Enable interrupt 0 by clearing its bit */
 149                tmp = readl(priv->base + PJ_INTERRUPT_MASK);
 150                writel(tmp & ~INT_0, priv->base + PJ_INTERRUPT_MASK);
 151        }
 152
 153        return 0;
 154}
 155
 156static void olpc_apsp_close(struct serio *port)
 157{
 158        struct olpc_apsp *priv = port->port_data;
 159        unsigned int tmp;
 160
 161        if (--priv->open_count == 0) {
 162                /* Disable interrupt 0 */
 163                tmp = readl(priv->base + PJ_INTERRUPT_MASK);
 164                writel(tmp | INT_0, priv->base + PJ_INTERRUPT_MASK);
 165        }
 166}
 167
 168static int olpc_apsp_probe(struct platform_device *pdev)
 169{
 170        struct serio *kb_serio, *pad_serio;
 171        struct olpc_apsp *priv;
 172        struct resource *res;
 173        int error;
 174
 175        priv = devm_kzalloc(&pdev->dev, sizeof(struct olpc_apsp), GFP_KERNEL);
 176        if (!priv)
 177                return -ENOMEM;
 178
 179        priv->dev = &pdev->dev;
 180
 181        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 182        priv->base = devm_ioremap_resource(&pdev->dev, res);
 183        if (IS_ERR(priv->base)) {
 184                dev_err(&pdev->dev, "Failed to map WTM registers\n");
 185                return PTR_ERR(priv->base);
 186        }
 187
 188        priv->irq = platform_get_irq(pdev, 0);
 189        if (priv->irq < 0)
 190                return priv->irq;
 191
 192        /* KEYBOARD */
 193        kb_serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
 194        if (!kb_serio)
 195                return -ENOMEM;
 196        kb_serio->id.type       = SERIO_8042_XL;
 197        kb_serio->write         = olpc_apsp_write;
 198        kb_serio->open          = olpc_apsp_open;
 199        kb_serio->close         = olpc_apsp_close;
 200        kb_serio->port_data     = priv;
 201        kb_serio->dev.parent    = &pdev->dev;
 202        strlcpy(kb_serio->name, "sp keyboard", sizeof(kb_serio->name));
 203        strlcpy(kb_serio->phys, "sp/serio0", sizeof(kb_serio->phys));
 204        priv->kbio              = kb_serio;
 205        serio_register_port(kb_serio);
 206
 207        /* TOUCHPAD */
 208        pad_serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
 209        if (!pad_serio) {
 210                error = -ENOMEM;
 211                goto err_pad;
 212        }
 213        pad_serio->id.type      = SERIO_8042;
 214        pad_serio->write        = olpc_apsp_write;
 215        pad_serio->open         = olpc_apsp_open;
 216        pad_serio->close        = olpc_apsp_close;
 217        pad_serio->port_data    = priv;
 218        pad_serio->dev.parent   = &pdev->dev;
 219        strlcpy(pad_serio->name, "sp touchpad", sizeof(pad_serio->name));
 220        strlcpy(pad_serio->phys, "sp/serio1", sizeof(pad_serio->phys));
 221        priv->padio             = pad_serio;
 222        serio_register_port(pad_serio);
 223
 224        error = request_irq(priv->irq, olpc_apsp_rx, 0, "olpc-apsp", priv);
 225        if (error) {
 226                dev_err(&pdev->dev, "Failed to request IRQ\n");
 227                goto err_irq;
 228        }
 229
 230        device_init_wakeup(priv->dev, 1);
 231        platform_set_drvdata(pdev, priv);
 232
 233        dev_dbg(&pdev->dev, "probed successfully.\n");
 234        return 0;
 235
 236err_irq:
 237        serio_unregister_port(pad_serio);
 238err_pad:
 239        serio_unregister_port(kb_serio);
 240        return error;
 241}
 242
 243static int olpc_apsp_remove(struct platform_device *pdev)
 244{
 245        struct olpc_apsp *priv = platform_get_drvdata(pdev);
 246
 247        free_irq(priv->irq, priv);
 248
 249        serio_unregister_port(priv->kbio);
 250        serio_unregister_port(priv->padio);
 251
 252        return 0;
 253}
 254
 255static const struct of_device_id olpc_apsp_dt_ids[] = {
 256        { .compatible = "olpc,ap-sp", },
 257        {}
 258};
 259MODULE_DEVICE_TABLE(of, olpc_apsp_dt_ids);
 260
 261static struct platform_driver olpc_apsp_driver = {
 262        .probe          = olpc_apsp_probe,
 263        .remove         = olpc_apsp_remove,
 264        .driver         = {
 265                .name   = "olpc-apsp",
 266                .of_match_table = olpc_apsp_dt_ids,
 267        },
 268};
 269
 270MODULE_DESCRIPTION("OLPC AP-SP serio driver");
 271MODULE_LICENSE("GPL");
 272module_platform_driver(olpc_apsp_driver);
 273