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_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 /* Bit definitions for ISR/IER registers. Both the registers have the same bit 49 * definitions and are only defined once. */ 50 #define XPS2_IPIXR_WDT_TOUT 0x00000001 /* Watchdog Timeout Interrupt */ 51 #define XPS2_IPIXR_TX_NOACK 0x00000002 /* Transmit No ACK Interrupt */ 52 #define XPS2_IPIXR_TX_ACK 0x00000004 /* Transmit ACK (Data) Interrupt */ 53 #define XPS2_IPIXR_RX_OVF 0x00000008 /* Receive Overflow Interrupt */ 54 #define XPS2_IPIXR_RX_ERR 0x00000010 /* Receive Error Interrupt */ 55 #define XPS2_IPIXR_RX_FULL 0x00000020 /* Receive Data Interrupt */ 56 57 /* Mask for all the Transmit Interrupts */ 58 #define XPS2_IPIXR_TX_ALL (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_TX_ACK) 59 60 /* Mask for all the Receive Interrupts */ 61 #define XPS2_IPIXR_RX_ALL (XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR | \ 62 XPS2_IPIXR_RX_FULL) 63 64 /* Mask for all the Interrupts */ 65 #define XPS2_IPIXR_ALL (XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL | \ 66 XPS2_IPIXR_WDT_TOUT) 67 68 /* Global Interrupt Enable mask */ 69 #define XPS2_GIER_GIE_MASK 0x80000000 70 71 struct xps2data { 72 int irq; 73 spinlock_t lock; 74 void __iomem *base_address; /* virt. address of control registers */ 75 unsigned int flags; 76 struct serio *serio; /* serio */ 77 struct device *dev; 78 }; 79 80 /************************************/ 81 /* XPS PS/2 data transmission calls */ 82 /************************************/ 83 84 /** 85 * xps2_recv() - attempts to receive a byte from the PS/2 port. 86 * @drvdata: pointer to ps2 device private data structure 87 * @byte: address where the read data will be copied 88 * 89 * If there is any data available in the PS/2 receiver, this functions reads 90 * the data, otherwise it returns error. 91 */ 92 static int xps2_recv(struct xps2data *drvdata, u8 *byte) 93 { 94 u32 sr; 95 int status = -1; 96 97 /* If there is data available in the PS/2 receiver, read it */ 98 sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET); 99 if (sr & XPS2_STATUS_RX_FULL) { 100 *byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET); 101 status = 0; 102 } 103 104 return status; 105 } 106 107 /*********************/ 108 /* Interrupt handler */ 109 /*********************/ 110 static irqreturn_t xps2_interrupt(int irq, void *dev_id) 111 { 112 struct xps2data *drvdata = dev_id; 113 u32 intr_sr; 114 u8 c; 115 int status; 116 117 /* Get the PS/2 interrupts and clear them */ 118 intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET); 119 out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr); 120 121 /* Check which interrupt is active */ 122 if (intr_sr & XPS2_IPIXR_RX_OVF) 123 dev_warn(drvdata->dev, "receive overrun error\n"); 124 125 if (intr_sr & XPS2_IPIXR_RX_ERR) 126 drvdata->flags |= SERIO_PARITY; 127 128 if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT)) 129 drvdata->flags |= SERIO_TIMEOUT; 130 131 if (intr_sr & XPS2_IPIXR_RX_FULL) { 132 status = xps2_recv(drvdata, &c); 133 134 /* Error, if a byte is not received */ 135 if (status) { 136 dev_err(drvdata->dev, 137 "wrong rcvd byte count (%d)\n", status); 138 } else { 139 serio_interrupt(drvdata->serio, c, drvdata->flags); 140 drvdata->flags = 0; 141 } 142 } 143 144 return IRQ_HANDLED; 145 } 146 147 /*******************/ 148 /* serio callbacks */ 149 /*******************/ 150 151 /** 152 * sxps2_write() - sends a byte out through the PS/2 port. 153 * @pserio: pointer to the serio structure of the PS/2 port 154 * @c: data that needs to be written to the PS/2 port 155 * 156 * This function checks if the PS/2 transmitter is empty and sends a byte. 157 * Otherwise it returns error. Transmission fails only when nothing is connected 158 * to the PS/2 port. Thats why, we do not try to resend the data in case of a 159 * failure. 160 */ 161 static int sxps2_write(struct serio *pserio, unsigned char c) 162 { 163 struct xps2data *drvdata = pserio->port_data; 164 unsigned long flags; 165 u32 sr; 166 int status = -1; 167 168 spin_lock_irqsave(&drvdata->lock, flags); 169 170 /* If the PS/2 transmitter is empty send a byte of data */ 171 sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET); 172 if (!(sr & XPS2_STATUS_TX_FULL)) { 173 out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c); 174 status = 0; 175 } 176 177 spin_unlock_irqrestore(&drvdata->lock, flags); 178 179 return status; 180 } 181 182 /** 183 * sxps2_open() - called when a port is opened by the higher layer. 184 * @pserio: pointer to the serio structure of the PS/2 device 185 * 186 * This function requests irq and enables interrupts for the PS/2 device. 187 */ 188 static int sxps2_open(struct serio *pserio) 189 { 190 struct xps2data *drvdata = pserio->port_data; 191 int error; 192 u8 c; 193 194 error = request_irq(drvdata->irq, &xps2_interrupt, 0, 195 DRIVER_NAME, drvdata); 196 if (error) { 197 dev_err(drvdata->dev, 198 "Couldn't allocate interrupt %d\n", drvdata->irq); 199 return error; 200 } 201 202 /* start reception by enabling the interrupts */ 203 out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK); 204 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL); 205 (void)xps2_recv(drvdata, &c); 206 207 return 0; /* success */ 208 } 209 210 /** 211 * sxps2_close() - frees the interrupt. 212 * @pserio: pointer to the serio structure of the PS/2 device 213 * 214 * This function frees the irq and disables interrupts for the PS/2 device. 215 */ 216 static void sxps2_close(struct serio *pserio) 217 { 218 struct xps2data *drvdata = pserio->port_data; 219 220 /* Disable the PS2 interrupts */ 221 out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00); 222 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00); 223 free_irq(drvdata->irq, drvdata); 224 } 225 226 /** 227 * xps2_of_probe - probe method for the PS/2 device. 228 * @of_dev: pointer to OF device structure 229 * @match: pointer to the structure used for matching a device 230 * 231 * This function probes the PS/2 device in the device tree. 232 * It initializes the driver data structure and the hardware. 233 * It returns 0, if the driver is bound to the PS/2 device, or a negative 234 * value if there is an error. 235 */ 236 static int xps2_of_probe(struct platform_device *ofdev) 237 { 238 struct resource r_irq; /* Interrupt resources */ 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 int error; 245 246 dev_info(dev, "Device Tree Probing \'%s\'\n", 247 ofdev->dev.of_node->name); 248 249 /* Get iospace for the device */ 250 error = of_address_to_resource(ofdev->dev.of_node, 0, &r_mem); 251 if (error) { 252 dev_err(dev, "invalid address\n"); 253 return error; 254 } 255 256 /* Get IRQ for the device */ 257 if (!of_irq_to_resource(ofdev->dev.of_node, 0, &r_irq)) { 258 dev_err(dev, "no IRQ found\n"); 259 return -ENODEV; 260 } 261 262 drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL); 263 serio = kzalloc(sizeof(struct serio), GFP_KERNEL); 264 if (!drvdata || !serio) { 265 error = -ENOMEM; 266 goto failed1; 267 } 268 269 spin_lock_init(&drvdata->lock); 270 drvdata->irq = r_irq.start; 271 drvdata->serio = serio; 272 drvdata->dev = dev; 273 274 phys_addr = r_mem.start; 275 remap_size = resource_size(&r_mem); 276 if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) { 277 dev_err(dev, "Couldn't lock memory region at 0x%08llX\n", 278 (unsigned long long)phys_addr); 279 error = -EBUSY; 280 goto failed1; 281 } 282 283 /* Fill in configuration data and add them to the list */ 284 drvdata->base_address = ioremap(phys_addr, remap_size); 285 if (drvdata->base_address == NULL) { 286 dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n", 287 (unsigned long long)phys_addr); 288 error = -EFAULT; 289 goto failed2; 290 } 291 292 /* Disable all the interrupts, just in case */ 293 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0); 294 295 /* Reset the PS2 device and abort any current transaction, to make sure 296 * we have the PS2 in a good state */ 297 out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET); 298 299 dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n", 300 (unsigned long long)phys_addr, drvdata->base_address, 301 drvdata->irq); 302 303 serio->id.type = SERIO_8042; 304 serio->write = sxps2_write; 305 serio->open = sxps2_open; 306 serio->close = sxps2_close; 307 serio->port_data = drvdata; 308 serio->dev.parent = dev; 309 snprintf(serio->name, sizeof(serio->name), 310 "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr); 311 snprintf(serio->phys, sizeof(serio->phys), 312 "xilinxps2/serio at %08llX", (unsigned long long)phys_addr); 313 314 serio_register_port(serio); 315 316 platform_set_drvdata(ofdev, drvdata); 317 return 0; /* success */ 318 319 failed2: 320 release_mem_region(phys_addr, remap_size); 321 failed1: 322 kfree(serio); 323 kfree(drvdata); 324 325 return error; 326 } 327 328 /** 329 * xps2_of_remove - unbinds the driver from the PS/2 device. 330 * @of_dev: pointer to OF device structure 331 * 332 * This function is called if a device is physically removed from the system or 333 * if the driver module is being unloaded. It frees any resources allocated to 334 * the device. 335 */ 336 static int xps2_of_remove(struct platform_device *of_dev) 337 { 338 struct xps2data *drvdata = platform_get_drvdata(of_dev); 339 struct resource r_mem; /* IO mem resources */ 340 341 serio_unregister_port(drvdata->serio); 342 iounmap(drvdata->base_address); 343 344 /* Get iospace of the device */ 345 if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem)) 346 dev_err(drvdata->dev, "invalid address\n"); 347 else 348 release_mem_region(r_mem.start, resource_size(&r_mem)); 349 350 kfree(drvdata); 351 352 platform_set_drvdata(of_dev, NULL); 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