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 63 struct 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 72 static 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 } 100 101 static 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 } 134 135 static 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 } 155 156 static 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 } 167 168 static 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 strscpy(kb_serio->name, "sp keyboard", sizeof(kb_serio->name)); 203 strscpy(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 strscpy(pad_serio->name, "sp touchpad", sizeof(pad_serio->name)); 220 strscpy(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; 235 236 err_irq: 237 serio_unregister_port(pad_serio); 238 err_pad: 239 serio_unregister_port(kb_serio); 240 return error; 241 } 242 243 static 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 } 254 255 static const struct of_device_id olpc_apsp_dt_ids[] = { 256 { .compatible = "olpc,ap-sp", }, 257 {} 258 }; 259 MODULE_DEVICE_TABLE(of, olpc_apsp_dt_ids); 260 261 static 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 }; 269 270 MODULE_DESCRIPTION("OLPC AP-SP serio driver"); 271 MODULE_LICENSE("GPL"); 272 module_platform_driver(olpc_apsp_driver); 273