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