1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Xilinx XPS PS/2 device driver 4 * 5 * (c) 2005 MontaVista Software, Inc. 6 * (c) 2008 Xilinx, Inc. 7 */ 8 9 10 #include <linux/module.h> 11 #include <linux/serio.h> 12 #include <linux/interrupt.h> 13 #include <linux/errno.h> 14 #include <linux/slab.h> 15 #include <linux/list.h> 16 #include <linux/io.h> 17 #include <linux/mod_devicetable.h> 18 #include <linux/of_address.h> 19 #include <linux/of_irq.h> 20 #include <linux/platform_device.h> 21 22 #define DRIVER_NAME "xilinx_ps2" 23 24 /* Register offsets for the xps2 device */ 25 #define XPS2_SRST_OFFSET 0x00000000 /* Software Reset register */ 26 #define XPS2_STATUS_OFFSET 0x00000004 /* Status register */ 27 #define XPS2_RX_DATA_OFFSET 0x00000008 /* Receive Data register */ 28 #define XPS2_TX_DATA_OFFSET 0x0000000C /* Transmit Data register */ 29 #define XPS2_GIER_OFFSET 0x0000002C /* Global Interrupt Enable reg */ 30 #define XPS2_IPISR_OFFSET 0x00000030 /* Interrupt Status register */ 31 #define XPS2_IPIER_OFFSET 0x00000038 /* Interrupt Enable register */ 32 33 /* Reset Register Bit Definitions */ 34 #define XPS2_SRST_RESET 0x0000000A /* Software Reset */ 35 36 /* Status Register Bit Positions */ 37 #define XPS2_STATUS_RX_FULL 0x00000001 /* Receive Full */ 38 #define XPS2_STATUS_TX_FULL 0x00000002 /* Transmit Full */ 39 40 /* 41 * Bit definitions for ISR/IER registers. Both the registers have the same bit 42 * definitions and are only defined once. 43 */ 44 #define XPS2_IPIXR_WDT_TOUT 0x00000001 /* Watchdog Timeout Interrupt */ 45 #define XPS2_IPIXR_TX_NOACK 0x00000002 /* Transmit No ACK Interrupt */ 46 #define XPS2_IPIXR_TX_ACK 0x00000004 /* Transmit ACK (Data) Interrupt */ 47 #define XPS2_IPIXR_RX_OVF 0x00000008 /* Receive Overflow Interrupt */ 48 #define XPS2_IPIXR_RX_ERR 0x00000010 /* Receive Error Interrupt */ 49 #define XPS2_IPIXR_RX_FULL 0x00000020 /* Receive Data Interrupt */ 50 51 /* Mask for all the Transmit Interrupts */ 52 #define XPS2_IPIXR_TX_ALL (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_TX_ACK) 53 54 /* Mask for all the Receive Interrupts */ 55 #define XPS2_IPIXR_RX_ALL (XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR | \ 56 XPS2_IPIXR_RX_FULL) 57 58 /* Mask for all the Interrupts */ 59 #define XPS2_IPIXR_ALL (XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL | \ 60 XPS2_IPIXR_WDT_TOUT) 61 62 /* Global Interrupt Enable mask */ 63 #define XPS2_GIER_GIE_MASK 0x80000000 64 65 struct xps2data { 66 int irq; 67 spinlock_t lock; 68 void __iomem *base_address; /* virt. address of control registers */ 69 unsigned int flags; 70 struct serio *serio; /* serio */ 71 struct device *dev; 72 }; 73 74 /************************************/ 75 /* XPS PS/2 data transmission calls */ 76 /************************************/ 77 78 /** 79 * xps2_recv() - attempts to receive a byte from the PS/2 port. 80 * @drvdata: pointer to ps2 device private data structure 81 * @byte: address where the read data will be copied 82 * 83 * If there is any data available in the PS/2 receiver, this functions reads 84 * the data, otherwise it returns error. 85 */ 86 static int xps2_recv(struct xps2data *drvdata, u8 *byte) 87 { 88 u32 sr; 89 int status = -1; 90 91 /* If there is data available in the PS/2 receiver, read it */ 92 sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET); 93 if (sr & XPS2_STATUS_RX_FULL) { 94 *byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET); 95 status = 0; 96 } 97 98 return status; 99 } 100 101 /*********************/ 102 /* Interrupt handler */ 103 /*********************/ 104 static irqreturn_t xps2_interrupt(int irq, void *dev_id) 105 { 106 struct xps2data *drvdata = dev_id; 107 u32 intr_sr; 108 u8 c; 109 int status; 110 111 /* Get the PS/2 interrupts and clear them */ 112 intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET); 113 out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr); 114 115 /* Check which interrupt is active */ 116 if (intr_sr & XPS2_IPIXR_RX_OVF) 117 dev_warn(drvdata->dev, "receive overrun error\n"); 118 119 if (intr_sr & XPS2_IPIXR_RX_ERR) 120 drvdata->flags |= SERIO_PARITY; 121 122 if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT)) 123 drvdata->flags |= SERIO_TIMEOUT; 124 125 if (intr_sr & XPS2_IPIXR_RX_FULL) { 126 status = xps2_recv(drvdata, &c); 127 128 /* Error, if a byte is not received */ 129 if (status) { 130 dev_err(drvdata->dev, 131 "wrong rcvd byte count (%d)\n", status); 132 } else { 133 serio_interrupt(drvdata->serio, c, drvdata->flags); 134 drvdata->flags = 0; 135 } 136 } 137 138 return IRQ_HANDLED; 139 } 140 141 /*******************/ 142 /* serio callbacks */ 143 /*******************/ 144 145 /** 146 * sxps2_write() - sends a byte out through the PS/2 port. 147 * @pserio: pointer to the serio structure of the PS/2 port 148 * @c: data that needs to be written to the PS/2 port 149 * 150 * This function checks if the PS/2 transmitter is empty and sends a byte. 151 * Otherwise it returns error. Transmission fails only when nothing is connected 152 * to the PS/2 port. Thats why, we do not try to resend the data in case of a 153 * failure. 154 */ 155 static int sxps2_write(struct serio *pserio, unsigned char c) 156 { 157 struct xps2data *drvdata = pserio->port_data; 158 unsigned long flags; 159 u32 sr; 160 int status = -1; 161 162 spin_lock_irqsave(&drvdata->lock, flags); 163 164 /* If the PS/2 transmitter is empty send a byte of data */ 165 sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET); 166 if (!(sr & XPS2_STATUS_TX_FULL)) { 167 out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c); 168 status = 0; 169 } 170 171 spin_unlock_irqrestore(&drvdata->lock, flags); 172 173 return status; 174 } 175 176 /** 177 * sxps2_open() - called when a port is opened by the higher layer. 178 * @pserio: pointer to the serio structure of the PS/2 device 179 * 180 * This function requests irq and enables interrupts for the PS/2 device. 181 */ 182 static int sxps2_open(struct serio *pserio) 183 { 184 struct xps2data *drvdata = pserio->port_data; 185 int error; 186 u8 c; 187 188 error = request_irq(drvdata->irq, &xps2_interrupt, 0, 189 DRIVER_NAME, drvdata); 190 if (error) { 191 dev_err(drvdata->dev, 192 "Couldn't allocate interrupt %d\n", drvdata->irq); 193 return error; 194 } 195 196 /* start reception by enabling the interrupts */ 197 out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK); 198 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL); 199 (void)xps2_recv(drvdata, &c); 200 201 return 0; /* success */ 202 } 203 204 /** 205 * sxps2_close() - frees the interrupt. 206 * @pserio: pointer to the serio structure of the PS/2 device 207 * 208 * This function frees the irq and disables interrupts for the PS/2 device. 209 */ 210 static void sxps2_close(struct serio *pserio) 211 { 212 struct xps2data *drvdata = pserio->port_data; 213 214 /* Disable the PS2 interrupts */ 215 out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00); 216 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00); 217 free_irq(drvdata->irq, drvdata); 218 } 219 220 /** 221 * xps2_of_probe - probe method for the PS/2 device. 222 * @of_dev: pointer to OF device structure 223 * @match: pointer to the structure used for matching a device 224 * 225 * This function probes the PS/2 device in the device tree. 226 * It initializes the driver data structure and the hardware. 227 * It returns 0, if the driver is bound to the PS/2 device, or a negative 228 * value if there is an error. 229 */ 230 static int xps2_of_probe(struct platform_device *ofdev) 231 { 232 struct resource r_mem; /* IO mem resources */ 233 struct xps2data *drvdata; 234 struct serio *serio; 235 struct device *dev = &ofdev->dev; 236 resource_size_t remap_size, phys_addr; 237 unsigned int irq; 238 int error; 239 240 dev_info(dev, "Device Tree Probing \'%pOFn\'\n", dev->of_node); 241 242 /* Get iospace for the device */ 243 error = of_address_to_resource(dev->of_node, 0, &r_mem); 244 if (error) { 245 dev_err(dev, "invalid address\n"); 246 return error; 247 } 248 249 /* Get IRQ for the device */ 250 irq = irq_of_parse_and_map(dev->of_node, 0); 251 if (!irq) { 252 dev_err(dev, "no IRQ found\n"); 253 return -ENODEV; 254 } 255 256 drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL); 257 serio = kzalloc(sizeof(struct serio), GFP_KERNEL); 258 if (!drvdata || !serio) { 259 error = -ENOMEM; 260 goto failed1; 261 } 262 263 spin_lock_init(&drvdata->lock); 264 drvdata->irq = irq; 265 drvdata->serio = serio; 266 drvdata->dev = dev; 267 268 phys_addr = r_mem.start; 269 remap_size = resource_size(&r_mem); 270 if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) { 271 dev_err(dev, "Couldn't lock memory region at 0x%08llX\n", 272 (unsigned long long)phys_addr); 273 error = -EBUSY; 274 goto failed1; 275 } 276 277 /* Fill in configuration data and add them to the list */ 278 drvdata->base_address = ioremap(phys_addr, remap_size); 279 if (drvdata->base_address == NULL) { 280 dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n", 281 (unsigned long long)phys_addr); 282 error = -EFAULT; 283 goto failed2; 284 } 285 286 /* Disable all the interrupts, just in case */ 287 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0); 288 289 /* 290 * Reset the PS2 device and abort any current transaction, 291 * to make sure we have the PS2 in a good state. 292 */ 293 out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET); 294 295 dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n", 296 (unsigned long long)phys_addr, drvdata->base_address, 297 drvdata->irq); 298 299 serio->id.type = SERIO_8042; 300 serio->write = sxps2_write; 301 serio->open = sxps2_open; 302 serio->close = sxps2_close; 303 serio->port_data = drvdata; 304 serio->dev.parent = dev; 305 snprintf(serio->name, sizeof(serio->name), 306 "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr); 307 snprintf(serio->phys, sizeof(serio->phys), 308 "xilinxps2/serio at %08llX", (unsigned long long)phys_addr); 309 310 serio_register_port(serio); 311 312 platform_set_drvdata(ofdev, drvdata); 313 return 0; /* success */ 314 315 failed2: 316 release_mem_region(phys_addr, remap_size); 317 failed1: 318 kfree(serio); 319 kfree(drvdata); 320 321 return error; 322 } 323 324 /** 325 * xps2_of_remove - unbinds the driver from the PS/2 device. 326 * @of_dev: pointer to OF device structure 327 * 328 * This function is called if a device is physically removed from the system or 329 * if the driver module is being unloaded. It frees any resources allocated to 330 * the device. 331 */ 332 static int xps2_of_remove(struct platform_device *of_dev) 333 { 334 struct xps2data *drvdata = platform_get_drvdata(of_dev); 335 struct resource r_mem; /* IO mem resources */ 336 337 serio_unregister_port(drvdata->serio); 338 iounmap(drvdata->base_address); 339 340 /* Get iospace of the device */ 341 if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem)) 342 dev_err(drvdata->dev, "invalid address\n"); 343 else 344 release_mem_region(r_mem.start, resource_size(&r_mem)); 345 346 kfree(drvdata); 347 348 return 0; 349 } 350 351 /* Match table for of_platform binding */ 352 static const struct of_device_id xps2_of_match[] = { 353 { .compatible = "xlnx,xps-ps2-1.00.a", }, 354 { /* end of list */ }, 355 }; 356 MODULE_DEVICE_TABLE(of, xps2_of_match); 357 358 static struct platform_driver xps2_of_driver = { 359 .driver = { 360 .name = DRIVER_NAME, 361 .of_match_table = xps2_of_match, 362 }, 363 .probe = xps2_of_probe, 364 .remove = xps2_of_remove, 365 }; 366 module_platform_driver(xps2_of_driver); 367 368 MODULE_AUTHOR("Xilinx, Inc."); 369 MODULE_DESCRIPTION("Xilinx XPS PS/2 driver"); 370 MODULE_LICENSE("GPL"); 371 372