373 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Copyright (C) 2004 - 2006 rt2x00 SourceForge Project4 * <http://rt2x00.serialmonkey.com>5 *6 * Module: eeprom_93cx67 * Abstract: EEPROM reader routines for 93cx6 chipsets.8 * Supported chipsets: 93c46 & 93c66.9 */10 11#include <linux/kernel.h>12#include <linux/module.h>13#include <linux/delay.h>14#include <linux/eeprom_93cx6.h>15 16MODULE_AUTHOR("http://rt2x00.serialmonkey.com");17MODULE_VERSION("1.0");18MODULE_DESCRIPTION("EEPROM 93cx6 chip driver");19MODULE_LICENSE("GPL");20 21static inline void eeprom_93cx6_pulse_high(struct eeprom_93cx6 *eeprom)22{23 eeprom->reg_data_clock = 1;24 eeprom->register_write(eeprom);25 26 /*27 * Add a short delay for the pulse to work.28 * According to the specifications the "maximum minimum"29 * time should be 450ns.30 */31 ndelay(450);32}33 34static inline void eeprom_93cx6_pulse_low(struct eeprom_93cx6 *eeprom)35{36 eeprom->reg_data_clock = 0;37 eeprom->register_write(eeprom);38 39 /*40 * Add a short delay for the pulse to work.41 * According to the specifications the "maximum minimum"42 * time should be 450ns.43 */44 ndelay(450);45}46 47static void eeprom_93cx6_startup(struct eeprom_93cx6 *eeprom)48{49 /*50 * Clear all flags, and enable chip select.51 */52 eeprom->register_read(eeprom);53 eeprom->reg_data_in = 0;54 eeprom->reg_data_out = 0;55 eeprom->reg_data_clock = 0;56 eeprom->reg_chip_select = 1;57 eeprom->drive_data = 1;58 eeprom->register_write(eeprom);59 60 /*61 * kick a pulse.62 */63 eeprom_93cx6_pulse_high(eeprom);64 eeprom_93cx6_pulse_low(eeprom);65}66 67static void eeprom_93cx6_cleanup(struct eeprom_93cx6 *eeprom)68{69 /*70 * Clear chip_select and data_in flags.71 */72 eeprom->register_read(eeprom);73 eeprom->reg_data_in = 0;74 eeprom->reg_chip_select = 0;75 eeprom->register_write(eeprom);76 77 /*78 * kick a pulse.79 */80 eeprom_93cx6_pulse_high(eeprom);81 eeprom_93cx6_pulse_low(eeprom);82}83 84static void eeprom_93cx6_write_bits(struct eeprom_93cx6 *eeprom,85 const u16 data, const u16 count)86{87 unsigned int i;88 89 eeprom->register_read(eeprom);90 91 /*92 * Clear data flags.93 */94 eeprom->reg_data_in = 0;95 eeprom->reg_data_out = 0;96 eeprom->drive_data = 1;97 98 /*99 * Start writing all bits.100 */101 for (i = count; i > 0; i--) {102 /*103 * Check if this bit needs to be set.104 */105 eeprom->reg_data_in = !!(data & (1 << (i - 1)));106 107 /*108 * Write the bit to the eeprom register.109 */110 eeprom->register_write(eeprom);111 112 /*113 * Kick a pulse.114 */115 eeprom_93cx6_pulse_high(eeprom);116 eeprom_93cx6_pulse_low(eeprom);117 }118 119 eeprom->reg_data_in = 0;120 eeprom->register_write(eeprom);121}122 123static void eeprom_93cx6_read_bits(struct eeprom_93cx6 *eeprom,124 u16 *data, const u16 count)125{126 unsigned int i;127 u16 buf = 0;128 129 eeprom->register_read(eeprom);130 131 /*132 * Clear data flags.133 */134 eeprom->reg_data_in = 0;135 eeprom->reg_data_out = 0;136 eeprom->drive_data = 0;137 138 /*139 * Start reading all bits.140 */141 for (i = count; i > 0; i--) {142 eeprom_93cx6_pulse_high(eeprom);143 144 eeprom->register_read(eeprom);145 146 /*147 * Clear data_in flag.148 */149 eeprom->reg_data_in = 0;150 151 /*152 * Read if the bit has been set.153 */154 if (eeprom->reg_data_out)155 buf |= (1 << (i - 1));156 157 eeprom_93cx6_pulse_low(eeprom);158 }159 160 *data = buf;161}162 163/**164 * eeprom_93cx6_read - Read a word from eeprom165 * @eeprom: Pointer to eeprom structure166 * @word: Word index from where we should start reading167 * @data: target pointer where the information will have to be stored168 *169 * This function will read the eeprom data as host-endian word170 * into the given data pointer.171 */172void eeprom_93cx6_read(struct eeprom_93cx6 *eeprom, const u8 word,173 u16 *data)174{175 u16 command;176 177 /*178 * Initialize the eeprom register179 */180 eeprom_93cx6_startup(eeprom);181 182 /*183 * Select the read opcode and the word to be read.184 */185 command = (PCI_EEPROM_READ_OPCODE << eeprom->width) | word;186 eeprom_93cx6_write_bits(eeprom, command,187 PCI_EEPROM_WIDTH_OPCODE + eeprom->width);188 189 /*190 * Read the requested 16 bits.191 */192 eeprom_93cx6_read_bits(eeprom, data, 16);193 194 /*195 * Cleanup eeprom register.196 */197 eeprom_93cx6_cleanup(eeprom);198}199EXPORT_SYMBOL_GPL(eeprom_93cx6_read);200 201/**202 * eeprom_93cx6_multiread - Read multiple words from eeprom203 * @eeprom: Pointer to eeprom structure204 * @word: Word index from where we should start reading205 * @data: target pointer where the information will have to be stored206 * @words: Number of words that should be read.207 *208 * This function will read all requested words from the eeprom,209 * this is done by calling eeprom_93cx6_read() multiple times.210 * But with the additional change that while the eeprom_93cx6_read211 * will return host ordered bytes, this method will return little212 * endian words.213 */214void eeprom_93cx6_multiread(struct eeprom_93cx6 *eeprom, const u8 word,215 __le16 *data, const u16 words)216{217 unsigned int i;218 u16 tmp;219 220 for (i = 0; i < words; i++) {221 tmp = 0;222 eeprom_93cx6_read(eeprom, word + i, &tmp);223 data[i] = cpu_to_le16(tmp);224 }225}226EXPORT_SYMBOL_GPL(eeprom_93cx6_multiread);227 228/**229 * eeprom_93cx6_readb - Read a byte from eeprom230 * @eeprom: Pointer to eeprom structure231 * @byte: Byte index from where we should start reading232 * @data: target pointer where the information will have to be stored233 *234 * This function will read a byte of the eeprom data235 * into the given data pointer.236 */237void eeprom_93cx6_readb(struct eeprom_93cx6 *eeprom, const u8 byte,238 u8 *data)239{240 u16 command;241 u16 tmp;242 243 /*244 * Initialize the eeprom register245 */246 eeprom_93cx6_startup(eeprom);247 248 /*249 * Select the read opcode and the byte to be read.250 */251 command = (PCI_EEPROM_READ_OPCODE << (eeprom->width + 1)) | byte;252 eeprom_93cx6_write_bits(eeprom, command,253 PCI_EEPROM_WIDTH_OPCODE + eeprom->width + 1);254 255 /*256 * Read the requested 8 bits.257 */258 eeprom_93cx6_read_bits(eeprom, &tmp, 8);259 *data = tmp & 0xff;260 261 /*262 * Cleanup eeprom register.263 */264 eeprom_93cx6_cleanup(eeprom);265}266EXPORT_SYMBOL_GPL(eeprom_93cx6_readb);267 268/**269 * eeprom_93cx6_multireadb - Read multiple bytes from eeprom270 * @eeprom: Pointer to eeprom structure271 * @byte: Index from where we should start reading272 * @data: target pointer where the information will have to be stored273 * @bytes: Number of bytes that should be read.274 *275 * This function will read all requested bytes from the eeprom,276 * this is done by calling eeprom_93cx6_readb() multiple times.277 */278void eeprom_93cx6_multireadb(struct eeprom_93cx6 *eeprom, const u8 byte,279 u8 *data, const u16 bytes)280{281 unsigned int i;282 283 for (i = 0; i < bytes; i++)284 eeprom_93cx6_readb(eeprom, byte + i, &data[i]);285}286EXPORT_SYMBOL_GPL(eeprom_93cx6_multireadb);287 288/**289 * eeprom_93cx6_wren - set the write enable state290 * @eeprom: Pointer to eeprom structure291 * @enable: true to enable writes, otherwise disable writes292 *293 * Set the EEPROM write enable state to either allow or deny294 * writes depending on the @enable value.295 */296void eeprom_93cx6_wren(struct eeprom_93cx6 *eeprom, bool enable)297{298 u16 command;299 300 /* start the command */301 eeprom_93cx6_startup(eeprom);302 303 /* create command to enable/disable */304 305 command = enable ? PCI_EEPROM_EWEN_OPCODE : PCI_EEPROM_EWDS_OPCODE;306 command <<= (eeprom->width - 2);307 308 eeprom_93cx6_write_bits(eeprom, command,309 PCI_EEPROM_WIDTH_OPCODE + eeprom->width);310 311 eeprom_93cx6_cleanup(eeprom);312}313EXPORT_SYMBOL_GPL(eeprom_93cx6_wren);314 315/**316 * eeprom_93cx6_write - write data to the EEPROM317 * @eeprom: Pointer to eeprom structure318 * @addr: Address to write data to.319 * @data: The data to write to address @addr.320 *321 * Write the @data to the specified @addr in the EEPROM and322 * waiting for the device to finish writing.323 *324 * Note, since we do not expect large number of write operations325 * we delay in between parts of the operation to avoid using excessive326 * amounts of CPU time busy waiting.327 */328void eeprom_93cx6_write(struct eeprom_93cx6 *eeprom, u8 addr, u16 data)329{330 int timeout = 100;331 u16 command;332 333 /* start the command */334 eeprom_93cx6_startup(eeprom);335 336 command = PCI_EEPROM_WRITE_OPCODE << eeprom->width;337 command |= addr;338 339 /* send write command */340 eeprom_93cx6_write_bits(eeprom, command,341 PCI_EEPROM_WIDTH_OPCODE + eeprom->width);342 343 /* send data */344 eeprom_93cx6_write_bits(eeprom, data, 16);345 346 /* get ready to check for busy */347 eeprom->drive_data = 0;348 eeprom->reg_chip_select = 1;349 eeprom->register_write(eeprom);350 351 /* wait at-least 250ns to get DO to be the busy signal */352 usleep_range(1000, 2000);353 354 /* wait for DO to go high to signify finish */355 356 while (true) {357 eeprom->register_read(eeprom);358 359 if (eeprom->reg_data_out)360 break;361 362 usleep_range(1000, 2000);363 364 if (--timeout <= 0) {365 printk(KERN_ERR "%s: timeout\n", __func__);366 break;367 }368 }369 370 eeprom_93cx6_cleanup(eeprom);371}372EXPORT_SYMBOL_GPL(eeprom_93cx6_write);373