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 #include <linux/clk.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 struct clk *clk; 79 int open_count; 80 int irq; 81 }; 82 83 static int olpc_apsp_write(struct serio *port, unsigned char val) 84 { 85 struct olpc_apsp *priv = port->port_data; 86 unsigned int i; 87 u32 which = 0; 88 89 if (port == priv->padio) 90 which = TOUCHPAD_PORT << PORT_SHIFT; 91 else 92 which = KEYBOARD_PORT << PORT_SHIFT; 93 94 dev_dbg(priv->dev, "olpc_apsp_write which=%x val=%x\n", which, val); 95 for (i = 0; i < 50; i++) { 96 u32 sts = readl(priv->base + COMMAND_FIFO_STATUS); 97 if ((sts & CMD_CNTR_MASK) < MAX_PENDING_CMDS) { 98 writel(which | val, 99 priv->base + SECURE_PROCESSOR_COMMAND); 100 return 0; 101 } 102 /* SP busy. This has not been seen in practice. */ 103 mdelay(1); 104 } 105 106 dev_dbg(priv->dev, "olpc_apsp_write timeout, status=%x\n", 107 readl(priv->base + COMMAND_FIFO_STATUS)); 108 109 return -ETIMEDOUT; 110 } 111 112 static irqreturn_t olpc_apsp_rx(int irq, void *dev_id) 113 { 114 struct olpc_apsp *priv = dev_id; 115 unsigned int w, tmp; 116 struct serio *serio; 117 118 /* 119 * Write 1 to PJ_RST_INTERRUPT to acknowledge and clear the interrupt 120 * Write 0xff00 to SECURE_PROCESSOR_COMMAND. 121 */ 122 tmp = readl(priv->base + PJ_RST_INTERRUPT); 123 if (!(tmp & SP_COMMAND_COMPLETE_RESET)) { 124 dev_warn(priv->dev, "spurious interrupt?\n"); 125 return IRQ_NONE; 126 } 127 128 w = readl(priv->base + COMMAND_RETURN_STATUS); 129 dev_dbg(priv->dev, "olpc_apsp_rx %x\n", w); 130 131 if (w >> PORT_SHIFT == KEYBOARD_PORT) 132 serio = priv->kbio; 133 else 134 serio = priv->padio; 135 136 serio_interrupt(serio, w & DATA_MASK, 0); 137 138 /* Ack and clear interrupt */ 139 writel(tmp | SP_COMMAND_COMPLETE_RESET, priv->base + PJ_RST_INTERRUPT); 140 writel(PORT_MASK, priv->base + SECURE_PROCESSOR_COMMAND); 141 142 pm_wakeup_event(priv->dev, 1000); 143 return IRQ_HANDLED; 144 } 145 146 static int olpc_apsp_open(struct serio *port) 147 { 148 struct olpc_apsp *priv = port->port_data; 149 unsigned int tmp; 150 unsigned long l; 151 int error; 152 153 if (priv->open_count++ == 0) { 154 error = clk_prepare_enable(priv->clk); 155 if (error) 156 return error; 157 158 l = readl(priv->base + COMMAND_FIFO_STATUS); 159 if (!(l & CMD_STS_MASK)) { 160 dev_err(priv->dev, "SP cannot accept commands.\n"); 161 clk_disable_unprepare(priv->clk); 162 return -EIO; 163 } 164 165 /* Enable interrupt 0 by clearing its bit */ 166 tmp = readl(priv->base + PJ_INTERRUPT_MASK); 167 writel(tmp & ~INT_0, priv->base + PJ_INTERRUPT_MASK); 168 } 169 170 return 0; 171 } 172 173 static void olpc_apsp_close(struct serio *port) 174 { 175 struct olpc_apsp *priv = port->port_data; 176 unsigned int tmp; 177 178 if (--priv->open_count == 0) { 179 /* Disable interrupt 0 */ 180 tmp = readl(priv->base + PJ_INTERRUPT_MASK); 181 writel(tmp | INT_0, priv->base + PJ_INTERRUPT_MASK); 182 183 clk_disable_unprepare(priv->clk); 184 } 185 } 186 187 static int olpc_apsp_probe(struct platform_device *pdev) 188 { 189 struct serio *kb_serio, *pad_serio; 190 struct olpc_apsp *priv; 191 struct resource *res; 192 int error; 193 194 priv = devm_kzalloc(&pdev->dev, sizeof(struct olpc_apsp), GFP_KERNEL); 195 if (!priv) 196 return -ENOMEM; 197 198 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 199 priv->base = devm_ioremap_resource(&pdev->dev, res); 200 if (IS_ERR(priv->base)) { 201 dev_err(&pdev->dev, "Failed to map WTM registers\n"); 202 return PTR_ERR(priv->base); 203 } 204 205 priv->irq = platform_get_irq(pdev, 0); 206 if (priv->irq < 0) 207 return priv->irq; 208 209 priv->clk = devm_clk_get(&pdev->dev, "sp"); 210 if (IS_ERR(priv->clk)) 211 return PTR_ERR(priv->clk); 212 213 /* KEYBOARD */ 214 kb_serio = kzalloc(sizeof(struct serio), GFP_KERNEL); 215 if (!kb_serio) 216 return -ENOMEM; 217 kb_serio->id.type = SERIO_8042_XL; 218 kb_serio->write = olpc_apsp_write; 219 kb_serio->open = olpc_apsp_open; 220 kb_serio->close = olpc_apsp_close; 221 kb_serio->port_data = priv; 222 kb_serio->dev.parent = &pdev->dev; 223 strlcpy(kb_serio->name, "sp keyboard", sizeof(kb_serio->name)); 224 strlcpy(kb_serio->phys, "sp/serio0", sizeof(kb_serio->phys)); 225 priv->kbio = kb_serio; 226 serio_register_port(kb_serio); 227 228 /* TOUCHPAD */ 229 pad_serio = kzalloc(sizeof(struct serio), GFP_KERNEL); 230 if (!pad_serio) { 231 error = -ENOMEM; 232 goto err_pad; 233 } 234 pad_serio->id.type = SERIO_8042; 235 pad_serio->write = olpc_apsp_write; 236 pad_serio->open = olpc_apsp_open; 237 pad_serio->close = olpc_apsp_close; 238 pad_serio->port_data = priv; 239 pad_serio->dev.parent = &pdev->dev; 240 strlcpy(pad_serio->name, "sp touchpad", sizeof(pad_serio->name)); 241 strlcpy(pad_serio->phys, "sp/serio1", sizeof(pad_serio->phys)); 242 priv->padio = pad_serio; 243 serio_register_port(pad_serio); 244 245 error = request_irq(priv->irq, olpc_apsp_rx, 0, "olpc-apsp", priv); 246 if (error) { 247 dev_err(&pdev->dev, "Failed to request IRQ\n"); 248 goto err_irq; 249 } 250 251 priv->dev = &pdev->dev; 252 device_init_wakeup(priv->dev, 1); 253 platform_set_drvdata(pdev, priv); 254 255 dev_dbg(&pdev->dev, "probed successfully.\n"); 256 return 0; 257 258 err_irq: 259 serio_unregister_port(pad_serio); 260 err_pad: 261 serio_unregister_port(kb_serio); 262 return error; 263 } 264 265 static int olpc_apsp_remove(struct platform_device *pdev) 266 { 267 struct olpc_apsp *priv = platform_get_drvdata(pdev); 268 269 free_irq(priv->irq, priv); 270 271 serio_unregister_port(priv->kbio); 272 serio_unregister_port(priv->padio); 273 274 return 0; 275 } 276 277 static const struct of_device_id olpc_apsp_dt_ids[] = { 278 { .compatible = "olpc,ap-sp", }, 279 {} 280 }; 281 MODULE_DEVICE_TABLE(of, olpc_apsp_dt_ids); 282 283 static struct platform_driver olpc_apsp_driver = { 284 .probe = olpc_apsp_probe, 285 .remove = olpc_apsp_remove, 286 .driver = { 287 .name = "olpc-apsp", 288 .of_match_table = olpc_apsp_dt_ids, 289 }, 290 }; 291 292 MODULE_DESCRIPTION("OLPC AP-SP serio driver"); 293 MODULE_LICENSE("GPL"); 294 module_platform_driver(olpc_apsp_driver); 295