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