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372 lines
8.4 KiB
372 lines
8.4 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Copyright (C) 2004 - 2006 rt2x00 SourceForge Project |
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* <http://rt2x00.serialmonkey.com> |
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* |
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* Module: eeprom_93cx6 |
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* Abstract: EEPROM reader routines for 93cx6 chipsets. |
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* Supported chipsets: 93c46 & 93c66. |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/delay.h> |
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#include <linux/eeprom_93cx6.h> |
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MODULE_AUTHOR("http://rt2x00.serialmonkey.com"); |
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MODULE_VERSION("1.0"); |
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MODULE_DESCRIPTION("EEPROM 93cx6 chip driver"); |
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MODULE_LICENSE("GPL"); |
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static inline void eeprom_93cx6_pulse_high(struct eeprom_93cx6 *eeprom) |
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{ |
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eeprom->reg_data_clock = 1; |
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eeprom->register_write(eeprom); |
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/* |
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* Add a short delay for the pulse to work. |
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* According to the specifications the "maximum minimum" |
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* time should be 450ns. |
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*/ |
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ndelay(450); |
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} |
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static inline void eeprom_93cx6_pulse_low(struct eeprom_93cx6 *eeprom) |
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{ |
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eeprom->reg_data_clock = 0; |
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eeprom->register_write(eeprom); |
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/* |
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* Add a short delay for the pulse to work. |
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* According to the specifications the "maximum minimum" |
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* time should be 450ns. |
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*/ |
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ndelay(450); |
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} |
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static void eeprom_93cx6_startup(struct eeprom_93cx6 *eeprom) |
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{ |
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/* |
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* Clear all flags, and enable chip select. |
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*/ |
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eeprom->register_read(eeprom); |
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eeprom->reg_data_in = 0; |
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eeprom->reg_data_out = 0; |
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eeprom->reg_data_clock = 0; |
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eeprom->reg_chip_select = 1; |
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eeprom->drive_data = 1; |
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eeprom->register_write(eeprom); |
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/* |
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* kick a pulse. |
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*/ |
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eeprom_93cx6_pulse_high(eeprom); |
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eeprom_93cx6_pulse_low(eeprom); |
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} |
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static void eeprom_93cx6_cleanup(struct eeprom_93cx6 *eeprom) |
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{ |
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/* |
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* Clear chip_select and data_in flags. |
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*/ |
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eeprom->register_read(eeprom); |
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eeprom->reg_data_in = 0; |
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eeprom->reg_chip_select = 0; |
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eeprom->register_write(eeprom); |
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/* |
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* kick a pulse. |
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*/ |
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eeprom_93cx6_pulse_high(eeprom); |
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eeprom_93cx6_pulse_low(eeprom); |
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} |
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static void eeprom_93cx6_write_bits(struct eeprom_93cx6 *eeprom, |
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const u16 data, const u16 count) |
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{ |
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unsigned int i; |
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eeprom->register_read(eeprom); |
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/* |
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* Clear data flags. |
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*/ |
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eeprom->reg_data_in = 0; |
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eeprom->reg_data_out = 0; |
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eeprom->drive_data = 1; |
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/* |
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* Start writing all bits. |
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*/ |
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for (i = count; i > 0; i--) { |
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/* |
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* Check if this bit needs to be set. |
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*/ |
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eeprom->reg_data_in = !!(data & (1 << (i - 1))); |
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/* |
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* Write the bit to the eeprom register. |
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*/ |
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eeprom->register_write(eeprom); |
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/* |
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* Kick a pulse. |
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*/ |
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eeprom_93cx6_pulse_high(eeprom); |
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eeprom_93cx6_pulse_low(eeprom); |
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} |
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eeprom->reg_data_in = 0; |
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eeprom->register_write(eeprom); |
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} |
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static void eeprom_93cx6_read_bits(struct eeprom_93cx6 *eeprom, |
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u16 *data, const u16 count) |
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{ |
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unsigned int i; |
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u16 buf = 0; |
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eeprom->register_read(eeprom); |
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/* |
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* Clear data flags. |
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*/ |
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eeprom->reg_data_in = 0; |
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eeprom->reg_data_out = 0; |
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eeprom->drive_data = 0; |
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/* |
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* Start reading all bits. |
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*/ |
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for (i = count; i > 0; i--) { |
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eeprom_93cx6_pulse_high(eeprom); |
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eeprom->register_read(eeprom); |
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/* |
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* Clear data_in flag. |
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*/ |
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eeprom->reg_data_in = 0; |
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/* |
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* Read if the bit has been set. |
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*/ |
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if (eeprom->reg_data_out) |
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buf |= (1 << (i - 1)); |
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eeprom_93cx6_pulse_low(eeprom); |
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} |
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*data = buf; |
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} |
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/** |
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* eeprom_93cx6_read - Read a word from eeprom |
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* @eeprom: Pointer to eeprom structure |
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* @word: Word index from where we should start reading |
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* @data: target pointer where the information will have to be stored |
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* |
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* This function will read the eeprom data as host-endian word |
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* into the given data pointer. |
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*/ |
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void eeprom_93cx6_read(struct eeprom_93cx6 *eeprom, const u8 word, |
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u16 *data) |
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{ |
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u16 command; |
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/* |
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* Initialize the eeprom register |
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*/ |
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eeprom_93cx6_startup(eeprom); |
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/* |
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* Select the read opcode and the word to be read. |
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*/ |
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command = (PCI_EEPROM_READ_OPCODE << eeprom->width) | word; |
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eeprom_93cx6_write_bits(eeprom, command, |
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PCI_EEPROM_WIDTH_OPCODE + eeprom->width); |
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/* |
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* Read the requested 16 bits. |
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*/ |
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eeprom_93cx6_read_bits(eeprom, data, 16); |
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/* |
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* Cleanup eeprom register. |
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*/ |
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eeprom_93cx6_cleanup(eeprom); |
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} |
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EXPORT_SYMBOL_GPL(eeprom_93cx6_read); |
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/** |
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* eeprom_93cx6_multiread - Read multiple words from eeprom |
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* @eeprom: Pointer to eeprom structure |
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* @word: Word index from where we should start reading |
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* @data: target pointer where the information will have to be stored |
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* @words: Number of words that should be read. |
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* |
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* This function will read all requested words from the eeprom, |
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* this is done by calling eeprom_93cx6_read() multiple times. |
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* But with the additional change that while the eeprom_93cx6_read |
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* will return host ordered bytes, this method will return little |
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* endian words. |
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*/ |
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void eeprom_93cx6_multiread(struct eeprom_93cx6 *eeprom, const u8 word, |
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__le16 *data, const u16 words) |
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{ |
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unsigned int i; |
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u16 tmp; |
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for (i = 0; i < words; i++) { |
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tmp = 0; |
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eeprom_93cx6_read(eeprom, word + i, &tmp); |
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data[i] = cpu_to_le16(tmp); |
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} |
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} |
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EXPORT_SYMBOL_GPL(eeprom_93cx6_multiread); |
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/** |
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* eeprom_93cx6_readb - Read a byte from eeprom |
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* @eeprom: Pointer to eeprom structure |
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* @byte: Byte index from where we should start reading |
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* @data: target pointer where the information will have to be stored |
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* |
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* This function will read a byte of the eeprom data |
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* into the given data pointer. |
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*/ |
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void eeprom_93cx6_readb(struct eeprom_93cx6 *eeprom, const u8 byte, |
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u8 *data) |
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{ |
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u16 command; |
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u16 tmp; |
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/* |
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* Initialize the eeprom register |
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*/ |
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eeprom_93cx6_startup(eeprom); |
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/* |
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* Select the read opcode and the byte to be read. |
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*/ |
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command = (PCI_EEPROM_READ_OPCODE << (eeprom->width + 1)) | byte; |
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eeprom_93cx6_write_bits(eeprom, command, |
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PCI_EEPROM_WIDTH_OPCODE + eeprom->width + 1); |
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/* |
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* Read the requested 8 bits. |
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*/ |
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eeprom_93cx6_read_bits(eeprom, &tmp, 8); |
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*data = tmp & 0xff; |
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/* |
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* Cleanup eeprom register. |
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*/ |
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eeprom_93cx6_cleanup(eeprom); |
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} |
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EXPORT_SYMBOL_GPL(eeprom_93cx6_readb); |
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/** |
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* eeprom_93cx6_multireadb - Read multiple bytes from eeprom |
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* @eeprom: Pointer to eeprom structure |
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* @byte: Index from where we should start reading |
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* @data: target pointer where the information will have to be stored |
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* @bytes: Number of bytes that should be read. |
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* |
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* This function will read all requested bytes from the eeprom, |
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* this is done by calling eeprom_93cx6_readb() multiple times. |
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*/ |
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void eeprom_93cx6_multireadb(struct eeprom_93cx6 *eeprom, const u8 byte, |
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u8 *data, const u16 bytes) |
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{ |
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unsigned int i; |
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for (i = 0; i < bytes; i++) |
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eeprom_93cx6_readb(eeprom, byte + i, &data[i]); |
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} |
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EXPORT_SYMBOL_GPL(eeprom_93cx6_multireadb); |
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/** |
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* eeprom_93cx6_wren - set the write enable state |
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* @eeprom: Pointer to eeprom structure |
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* @enable: true to enable writes, otherwise disable writes |
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* |
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* Set the EEPROM write enable state to either allow or deny |
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* writes depending on the @enable value. |
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*/ |
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void eeprom_93cx6_wren(struct eeprom_93cx6 *eeprom, bool enable) |
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{ |
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u16 command; |
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/* start the command */ |
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eeprom_93cx6_startup(eeprom); |
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/* create command to enable/disable */ |
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command = enable ? PCI_EEPROM_EWEN_OPCODE : PCI_EEPROM_EWDS_OPCODE; |
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command <<= (eeprom->width - 2); |
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eeprom_93cx6_write_bits(eeprom, command, |
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PCI_EEPROM_WIDTH_OPCODE + eeprom->width); |
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eeprom_93cx6_cleanup(eeprom); |
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} |
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EXPORT_SYMBOL_GPL(eeprom_93cx6_wren); |
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/** |
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* eeprom_93cx6_write - write data to the EEPROM |
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* @eeprom: Pointer to eeprom structure |
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* @addr: Address to write data to. |
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* @data: The data to write to address @addr. |
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* |
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* Write the @data to the specified @addr in the EEPROM and |
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* waiting for the device to finish writing. |
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* |
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* Note, since we do not expect large number of write operations |
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* we delay in between parts of the operation to avoid using excessive |
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* amounts of CPU time busy waiting. |
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*/ |
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void eeprom_93cx6_write(struct eeprom_93cx6 *eeprom, u8 addr, u16 data) |
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{ |
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int timeout = 100; |
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u16 command; |
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/* start the command */ |
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eeprom_93cx6_startup(eeprom); |
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command = PCI_EEPROM_WRITE_OPCODE << eeprom->width; |
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command |= addr; |
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/* send write command */ |
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eeprom_93cx6_write_bits(eeprom, command, |
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PCI_EEPROM_WIDTH_OPCODE + eeprom->width); |
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/* send data */ |
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eeprom_93cx6_write_bits(eeprom, data, 16); |
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/* get ready to check for busy */ |
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eeprom->drive_data = 0; |
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eeprom->reg_chip_select = 1; |
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eeprom->register_write(eeprom); |
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/* wait at-least 250ns to get DO to be the busy signal */ |
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usleep_range(1000, 2000); |
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/* wait for DO to go high to signify finish */ |
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while (true) { |
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eeprom->register_read(eeprom); |
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if (eeprom->reg_data_out) |
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break; |
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usleep_range(1000, 2000); |
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if (--timeout <= 0) { |
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printk(KERN_ERR "%s: timeout\n", __func__); |
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break; |
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} |
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} |
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eeprom_93cx6_cleanup(eeprom); |
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} |
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EXPORT_SYMBOL_GPL(eeprom_93cx6_write);
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