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); 285