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/* |
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* Cisco router simulation platform. |
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* Copyright (c) 2005,2006 Christophe Fillot (cf@utc.fr) |
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* |
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* NMC93C46/NMC93C56 Serial EEPROM. |
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*/ |
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|
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include <unistd.h> |
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|
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#include "nmc93cX6.h" |
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|
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#define DEBUG_EEPROM 0 |
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|
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/* Internal states */ |
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enum { |
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EEPROM_STATE_INACTIVE = 0, |
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EEPROM_STATE_WAIT_CMD, |
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EEPROM_STATE_DATAOUT, |
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}; |
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|
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/* Get command length for the specified group */ |
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static u_int nmc94cX6_get_cmd_len(struct nmc93cX6_group *g) |
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{ |
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switch(g->eeprom_type) { |
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case EEPROM_TYPE_NMC93C46: |
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return(NMC93C46_CMD_BITLEN); |
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case EEPROM_TYPE_NMC93C56: |
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return(NMC93C56_CMD_BITLEN); |
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default: |
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return(0); |
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} |
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} |
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|
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/* Extract EEPROM data address */ |
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static u_int nmc94cX6_get_addr(struct nmc93cX6_group *g,u_int cmd) |
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{ |
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switch(g->eeprom_type) { |
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case EEPROM_TYPE_NMC93C46: |
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return((cmd >> 3) & 0x3f); |
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case EEPROM_TYPE_NMC93C56: |
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return(m_reverse_u8((cmd >> 3) & 0xff)); |
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default: |
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return(0); |
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} |
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} |
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|
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/* Check chip select */ |
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static void nmc93cX6_check_cs(struct nmc93cX6_group *g,u_int old,u_int new) |
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{ |
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int i,res; |
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|
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for(i=0;i<g->nr_eeprom;i++) |
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{ |
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g->state[i].dataout_val = 1; |
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|
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if (g->debug) |
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{ |
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printf("EEPROM %s(%d): check_cs: check_bit(old,new,select_bit) " |
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"[%8.8x, %8.8x, %d (mask = %8.8x)] = %d\n", |
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g->description, i, |
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old, new, g->def[i]->select_bit, 1 << g->def[i]->select_bit, |
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check_bit(old,new,g->def[i]->select_bit)); |
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} |
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|
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if ((res = check_bit(old,new,g->def[i]->select_bit)) != 0) { |
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g->state[i].cmd_len = 0; /* no bit for command sent now */ |
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g->state[i].cmd_val = 0; |
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|
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if (res == 2) |
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g->state[i].state = EEPROM_STATE_WAIT_CMD; |
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else |
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g->state[i].state = EEPROM_STATE_INACTIVE; |
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} |
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} |
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} |
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|
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/* Check clock set for a specific group */ |
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static void nmc93cX6_check_clk_group(struct nmc93cX6_group *g,int group_id, |
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u_int old,u_int new) |
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{ |
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struct cisco_eeprom *eeprom; |
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u_int cmd,op,addr,pos; |
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u_int clk_bit, din_bit; |
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u_int cmd_len; |
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|
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clk_bit = g->def[group_id]->clock_bit; |
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din_bit = g->def[group_id]->din_bit; |
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|
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if (g->debug) |
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{ |
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printf("EEPROM %s(%d): check_clk: check_bit(old,new,select_bit) " |
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"[%8.8x, %8.8x, %d (mask = %8.8x)] = %d\n", |
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g->description, group_id, |
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old,new, clk_bit, 1 << clk_bit, check_bit(old,new,clk_bit)); |
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} |
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|
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/* CLK bit set ? */ |
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if (check_bit(old,new,clk_bit) != 2) |
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return; |
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|
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switch(g->state[group_id].state) |
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{ |
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case EEPROM_STATE_WAIT_CMD: |
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/* Read DATAIN bit */ |
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if (new & (1 << din_bit)) |
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g->state[group_id].cmd_val |= (1 << g->state[group_id].cmd_len); |
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|
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g->state[group_id].cmd_len++; |
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|
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cmd_len = nmc94cX6_get_cmd_len(g); |
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|
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/* Command is complete ? */ |
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if ((g->state[group_id].cmd_len == cmd_len) && |
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(g->state[group_id].cmd_val & 1)) |
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{ |
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#if DEBUG_EEPROM |
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printf("nmc93cX6: %s(%d): command = %x\n", |
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g->description,group_id,g->state[group_id].cmd_val); |
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#endif |
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g->state[group_id].cmd_len = 0; |
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|
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/* we have the command! extract the opcode */ |
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cmd = g->state[group_id].cmd_val; |
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op = cmd & 0x7; |
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|
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switch(op) { |
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case NMC93CX6_CMD_READ: |
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g->state[group_id].state = EEPROM_STATE_DATAOUT; |
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g->state[group_id].dataout_pos = 0; |
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break; |
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#if DEBUG_EEPROM |
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default: |
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printf("nmc93cX6: unhandled opcode %d\n",op); |
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#endif |
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} |
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} |
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|
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break; |
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|
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case EEPROM_STATE_DATAOUT: |
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/* |
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* user want to read data. we read 16-bits. |
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* extract address (6 bits) from command. |
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*/ |
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|
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cmd = g->state[group_id].cmd_val; |
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addr = nmc94cX6_get_addr(g,cmd); |
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|
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#if DEBUG_EEPROM |
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if (g->state[group_id].dataout_pos == 0) |
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printf("nmc93cX6: %s(%d): read addr=%x (%d), val = %4.4x\n", |
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g->description,group_id,addr,addr, |
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g->state[group_id].cmd_val); |
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#endif |
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|
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pos = g->state[group_id].dataout_pos++; |
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eeprom = g->eeprom[group_id]; |
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|
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if (eeprom && eeprom->data && (addr < eeprom->len)) { |
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g->state[group_id].dataout_val = eeprom->data[addr] & (1 << pos); |
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} else { |
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/* access out of bounds */ |
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g->state[group_id].dataout_val = (1 << pos); |
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} |
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|
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if (g->state[group_id].dataout_pos == NMC93CX6_CMD_DATALEN) { |
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g->state[group_id].state = EEPROM_STATE_INACTIVE; |
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g->state[group_id].dataout_pos = 0; |
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} |
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break; |
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|
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#if DEBUG_EEPROM |
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default: |
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printf("nmc93cX6: unhandled state %d\n",g->state[group_id].state); |
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#endif |
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} |
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} |
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|
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/* Check clock set for all group */ |
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void nmc93cX6_check_clk(struct nmc93cX6_group *g,u_int old,u_int new) |
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{ |
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int i; |
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|
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for(i=0;i<g->nr_eeprom;i++) |
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nmc93cX6_check_clk_group(g,i,old,new); |
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} |
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|
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/* Handle write */ |
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void nmc93cX6_write(struct nmc93cX6_group *g,u_int data) |
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{ |
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u_int new = data, old = g->eeprom_reg; |
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|
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nmc93cX6_check_cs(g,old,new); |
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nmc93cX6_check_clk(g,old,new); |
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g->eeprom_reg = new; |
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} |
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|
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/* Handle read */ |
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u_int nmc93cX6_read(struct nmc93cX6_group *g) |
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{ |
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u_int res; |
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int i; |
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|
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res = g->eeprom_reg; |
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|
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for(i=0;i<g->nr_eeprom;i++) { |
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if (!(g->eeprom_reg & (1 << g->def[i]->select_bit))) |
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continue; |
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|
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if (g->state[i].dataout_val) |
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res |= 1 << g->def[i]->dout_bit; |
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else |
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res &= ~(1 << g->def[i]->dout_bit); |
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} |
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|
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return(res); |
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} |
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