1 /* 2 * Xilinx XPS PS/2 device driver 3 * 4 * (c) 2005 MontaVista Software, Inc. 5 * (c) 2008 Xilinx, Inc. 6 * 7 * This program is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License as published by the 9 * Free Software Foundation; either version 2 of the License, or (at your 10 * option) any later version. 11 * 12 * You should have received a copy of the GNU General Public License along 13 * with this program; if not, write to the Free Software Foundation, Inc., 14 * 675 Mass Ave, Cambridge, MA 02139, USA. 15 */ 16 17 18 #include <linux/module.h> 19 #include <linux/serio.h> 20 #include <linux/interrupt.h> 21 #include <linux/errno.h> 22 #include <linux/slab.h> 23 #include <linux/list.h> 24 #include <linux/io.h> 25 #include <linux/of_address.h> 26 #include <linux/of_device.h> 27 #include <linux/of_irq.h> 28 #include <linux/of_platform.h> 29 30 #define DRIVER_NAME "xilinx_ps2" 31 32 /* Register offsets for the xps2 device */ 33 #define XPS2_SRST_OFFSET 0x00000000 /* Software Reset register */ 34 #define XPS2_STATUS_OFFSET 0x00000004 /* Status register */ 35 #define XPS2_RX_DATA_OFFSET 0x00000008 /* Receive Data register */ 36 #define XPS2_TX_DATA_OFFSET 0x0000000C /* Transmit Data register */ 37 #define XPS2_GIER_OFFSET 0x0000002C /* Global Interrupt Enable reg */ 38 #define XPS2_IPISR_OFFSET 0x00000030 /* Interrupt Status register */ 39 #define XPS2_IPIER_OFFSET 0x00000038 /* Interrupt Enable register */ 40 41 /* Reset Register Bit Definitions */ 42 #define XPS2_SRST_RESET 0x0000000A /* Software Reset */ 43 44 /* Status Register Bit Positions */ 45 #define XPS2_STATUS_RX_FULL 0x00000001 /* Receive Full */ 46 #define XPS2_STATUS_TX_FULL 0x00000002 /* Transmit Full */ 47 48 /* 49 * Bit definitions for ISR/IER registers. Both the registers have the same bit 50 * definitions and are only defined once. 51 */ 52 #define XPS2_IPIXR_WDT_TOUT 0x00000001 /* Watchdog Timeout Interrupt */ 53 #define XPS2_IPIXR_TX_NOACK 0x00000002 /* Transmit No ACK Interrupt */ 54 #define XPS2_IPIXR_TX_ACK 0x00000004 /* Transmit ACK (Data) Interrupt */ 55 #define XPS2_IPIXR_RX_OVF 0x00000008 /* Receive Overflow Interrupt */ 56 #define XPS2_IPIXR_RX_ERR 0x00000010 /* Receive Error Interrupt */ 57 #define XPS2_IPIXR_RX_FULL 0x00000020 /* Receive Data Interrupt */ 58 59 /* Mask for all the Transmit Interrupts */ 60 #define XPS2_IPIXR_TX_ALL (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_TX_ACK) 61 62 /* Mask for all the Receive Interrupts */ 63 #define XPS2_IPIXR_RX_ALL (XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR | \ 64 XPS2_IPIXR_RX_FULL) 65 66 /* Mask for all the Interrupts */ 67 #define XPS2_IPIXR_ALL (XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL | \ 68 XPS2_IPIXR_WDT_TOUT) 69 70 /* Global Interrupt Enable mask */ 71 #define XPS2_GIER_GIE_MASK 0x80000000 72 73 struct xps2data { 74 int irq; 75 spinlock_t lock; 76 void __iomem *base_address; /* virt. address of control registers */ 77 unsigned int flags; 78 struct serio *serio; /* serio */ 79 struct device *dev; 80 }; 81 82 /************************************/ 83 /* XPS PS/2 data transmission calls */ 84 /************************************/ 85 86 /** 87 * xps2_recv() - attempts to receive a byte from the PS/2 port. 88 * @drvdata: pointer to ps2 device private data structure 89 * @byte: address where the read data will be copied 90 * 91 * If there is any data available in the PS/2 receiver, this functions reads 92 * the data, otherwise it returns error. 93 */ 94 static int xps2_recv(struct xps2data *drvdata, u8 *byte) 95 { 96 u32 sr; 97 int status = -1; 98 99 /* If there is data available in the PS/2 receiver, read it */ 100 sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET); 101 if (sr & XPS2_STATUS_RX_FULL) { 102 *byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET); 103 status = 0; 104 } 105 106 return status; 107 } 108 109 /*********************/ 110 /* Interrupt handler */ 111 /*********************/ 112 static irqreturn_t xps2_interrupt(int irq, void *dev_id) 113 { 114 struct xps2data *drvdata = dev_id; 115 u32 intr_sr; 116 u8 c; 117 int status; 118 119 /* Get the PS/2 interrupts and clear them */ 120 intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET); 121 out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr); 122 123 /* Check which interrupt is active */ 124 if (intr_sr & XPS2_IPIXR_RX_OVF) 125 dev_warn(drvdata->dev, "receive overrun error\n"); 126 127 if (intr_sr & XPS2_IPIXR_RX_ERR) 128 drvdata->flags |= SERIO_PARITY; 129 130 if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT)) 131 drvdata->flags |= SERIO_TIMEOUT; 132 133 if (intr_sr & XPS2_IPIXR_RX_FULL) { 134 status = xps2_recv(drvdata, &c); 135 136 /* Error, if a byte is not received */ 137 if (status) { 138 dev_err(drvdata->dev, 139 "wrong rcvd byte count (%d)\n", status); 140 } else { 141 serio_interrupt(drvdata->serio, c, drvdata->flags); 142 drvdata->flags = 0; 143 } 144 } 145 146 return IRQ_HANDLED; 147 } 148 149 /*******************/ 150 /* serio callbacks */ 151 /*******************/ 152 153 /** 154 * sxps2_write() - sends a byte out through the PS/2 port. 155 * @pserio: pointer to the serio structure of the PS/2 port 156 * @c: data that needs to be written to the PS/2 port 157 * 158 * This function checks if the PS/2 transmitter is empty and sends a byte. 159 * Otherwise it returns error. Transmission fails only when nothing is connected 160 * to the PS/2 port. Thats why, we do not try to resend the data in case of a 161 * failure. 162 */ 163 static int sxps2_write(struct serio *pserio, unsigned char c) 164 { 165 struct xps2data *drvdata = pserio->port_data; 166 unsigned long flags; 167 u32 sr; 168 int status = -1; 169 170 spin_lock_irqsave(&drvdata->lock, flags); 171 172 /* If the PS/2 transmitter is empty send a byte of data */ 173 sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET); 174 if (!(sr & XPS2_STATUS_TX_FULL)) { 175 out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c); 176 status = 0; 177 } 178 179 spin_unlock_irqrestore(&drvdata->lock, flags); 180 181 return status; 182 } 183 184 /** 185 * sxps2_open() - called when a port is opened by the higher layer. 186 * @pserio: pointer to the serio structure of the PS/2 device 187 * 188 * This function requests irq and enables interrupts for the PS/2 device. 189 */ 190 static int sxps2_open(struct serio *pserio) 191 { 192 struct xps2data *drvdata = pserio->port_data; 193 int error; 194 u8 c; 195 196 error = request_irq(drvdata->irq, &xps2_interrupt, 0, 197 DRIVER_NAME, drvdata); 198 if (error) { 199 dev_err(drvdata->dev, 200 "Couldn't allocate interrupt %d\n", drvdata->irq); 201 return error; 202 } 203 204 /* start reception by enabling the interrupts */ 205 out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK); 206 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL); 207 (void)xps2_recv(drvdata, &c); 208 209 return 0; /* success */ 210 } 211 212 /** 213 * sxps2_close() - frees the interrupt. 214 * @pserio: pointer to the serio structure of the PS/2 device 215 * 216 * This function frees the irq and disables interrupts for the PS/2 device. 217 */ 218 static void sxps2_close(struct serio *pserio) 219 { 220 struct xps2data *drvdata = pserio->port_data; 221 222 /* Disable the PS2 interrupts */ 223 out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00); 224 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00); 225 free_irq(drvdata->irq, drvdata); 226 } 227 228 /** 229 * xps2_of_probe - probe method for the PS/2 device. 230 * @of_dev: pointer to OF device structure 231 * @match: pointer to the structure used for matching a device 232 * 233 * This function probes the PS/2 device in the device tree. 234 * It initializes the driver data structure and the hardware. 235 * It returns 0, if the driver is bound to the PS/2 device, or a negative 236 * value if there is an error. 237 */ 238 static int xps2_of_probe(struct platform_device *ofdev) 239 { 240 struct resource r_mem; /* IO mem resources */ 241 struct xps2data *drvdata; 242 struct serio *serio; 243 struct device *dev = &ofdev->dev; 244 resource_size_t remap_size, phys_addr; 245 unsigned int irq; 246 int error; 247 248 dev_info(dev, "Device Tree Probing \'%s\'\n", dev->of_node->name); 249 250 /* Get iospace for the device */ 251 error = of_address_to_resource(dev->of_node, 0, &r_mem); 252 if (error) { 253 dev_err(dev, "invalid address\n"); 254 return error; 255 } 256 257 /* Get IRQ for the device */ 258 irq = irq_of_parse_and_map(dev->of_node, 0); 259 if (!irq) { 260 dev_err(dev, "no IRQ found\n"); 261 return -ENODEV; 262 } 263 264 drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL); 265 serio = kzalloc(sizeof(struct serio), GFP_KERNEL); 266 if (!drvdata || !serio) { 267 error = -ENOMEM; 268 goto failed1; 269 } 270 271 spin_lock_init(&drvdata->lock); 272 drvdata->irq = irq; 273 drvdata->serio = serio; 274 drvdata->dev = dev; 275 276 phys_addr = r_mem.start; 277 remap_size = resource_size(&r_mem); 278 if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) { 279 dev_err(dev, "Couldn't lock memory region at 0x%08llX\n", 280 (unsigned long long)phys_addr); 281 error = -EBUSY; 282 goto failed1; 283 } 284 285 /* Fill in configuration data and add them to the list */ 286 drvdata->base_address = ioremap(phys_addr, remap_size); 287 if (drvdata->base_address == NULL) { 288 dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n", 289 (unsigned long long)phys_addr); 290 error = -EFAULT; 291 goto failed2; 292 } 293 294 /* Disable all the interrupts, just in case */ 295 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0); 296 297 /* 298 * Reset the PS2 device and abort any current transaction, 299 * to make sure we have the PS2 in a good state. 300 */ 301 out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET); 302 303 dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n", 304 (unsigned long long)phys_addr, drvdata->base_address, 305 drvdata->irq); 306 307 serio->id.type = SERIO_8042; 308 serio->write = sxps2_write; 309 serio->open = sxps2_open; 310 serio->close = sxps2_close; 311 serio->port_data = drvdata; 312 serio->dev.parent = dev; 313 snprintf(serio->name, sizeof(serio->name), 314 "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr); 315 snprintf(serio->phys, sizeof(serio->phys), 316 "xilinxps2/serio at %08llX", (unsigned long long)phys_addr); 317 318 serio_register_port(serio); 319 320 platform_set_drvdata(ofdev, drvdata); 321 return 0; /* success */ 322 323 failed2: 324 release_mem_region(phys_addr, remap_size); 325 failed1: 326 kfree(serio); 327 kfree(drvdata); 328 329 return error; 330 } 331 332 /** 333 * xps2_of_remove - unbinds the driver from the PS/2 device. 334 * @of_dev: pointer to OF device structure 335 * 336 * This function is called if a device is physically removed from the system or 337 * if the driver module is being unloaded. It frees any resources allocated to 338 * the device. 339 */ 340 static int xps2_of_remove(struct platform_device *of_dev) 341 { 342 struct xps2data *drvdata = platform_get_drvdata(of_dev); 343 struct resource r_mem; /* IO mem resources */ 344 345 serio_unregister_port(drvdata->serio); 346 iounmap(drvdata->base_address); 347 348 /* Get iospace of the device */ 349 if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem)) 350 dev_err(drvdata->dev, "invalid address\n"); 351 else 352 release_mem_region(r_mem.start, resource_size(&r_mem)); 353 354 kfree(drvdata); 355 356 return 0; 357 } 358 359 /* Match table for of_platform binding */ 360 static const struct of_device_id xps2_of_match[] = { 361 { .compatible = "xlnx,xps-ps2-1.00.a", }, 362 { /* end of list */ }, 363 }; 364 MODULE_DEVICE_TABLE(of, xps2_of_match); 365 366 static struct platform_driver xps2_of_driver = { 367 .driver = { 368 .name = DRIVER_NAME, 369 .of_match_table = xps2_of_match, 370 }, 371 .probe = xps2_of_probe, 372 .remove = xps2_of_remove, 373 }; 374 module_platform_driver(xps2_of_driver); 375 376 MODULE_AUTHOR("Xilinx, Inc."); 377 MODULE_DESCRIPTION("Xilinx XPS PS/2 driver"); 378 MODULE_LICENSE("GPL"); 379 380