diff options
Diffstat (limited to 'board/gth2/ee_access.c')
| -rw-r--r-- | board/gth2/ee_access.c | 347 |
1 files changed, 347 insertions, 0 deletions
diff --git a/board/gth2/ee_access.c b/board/gth2/ee_access.c new file mode 100644 index 0000000..d4798c4 --- /dev/null +++ b/board/gth2/ee_access.c @@ -0,0 +1,347 @@ +/* Module for handling DALLAS DS2438, smart battery monitor + Chip can store up to 40 bytes of user data in EEPROM, + perform temp, voltage and current measurements. + Chip also contains a unique serial number. + + Always read/write LSb first + + For documentaion, see data sheet for DS2438, 2438.pdf + + By Thomas.Lange@corelatus.com 001025 + + Copyright (C) 2000-2005 Corelatus AB */ + +/* This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <common.h> +#include <command.h> +#include <asm/au1x00.h> +#include <asm/io.h> +#include "ee_dev.h" +#include "ee_access.h" + +/* static int Debug = 1; */ +#undef E_DEBUG +#define E_DEBUG(fmt,args...) /* */ +/* #define E_DEBUG(fmt,args...) printk("EEA:"fmt,##args); */ + +/* We dont have kernel functions */ +#define printk printf +#define KERN_DEBUG +#define KERN_ERR +#define EIO 1 + +#ifndef TRUE +#define TRUE 1 +#endif +#ifndef FALSE +#define FALSE 0 +#endif + +/* lookup table ripped from DS app note 17, understanding and using cyclic redundancy checks... */ + +static u8 crc_lookup[256] = { + 0, 94, 188, 226, 97, 63, 221, 131, + 194, 156, 126, 32, 163, 253, 31, 65, + 157, 195, 33, 127, 252, 162, 64, 30, + 95, 1, 227, 189, 62, 96, 130, 220, + 35, 125, 159, 193, 66, 28, 254, 160, + 225, 191, 93, 3, 128, 222, 60, 98, + 190, 224, 2, 92, 223, 129, 99, 61, + 124, 34, 192, 158, 29, 67, 161, 255, + 70, 24, 250, 164, 39, 121, 155, 197, + 132, 218, 56, 102, 229, 187, 89, 7, + 219, 133, 103, 57, 186, 228, 6, 88, + 25, 71, 165, 251, 120, 38, 196, 154, + 101, 59, 217, 135, 4, 90, 184, 230, + 167, 249, 27, 69, 198, 152, 122, 36, + 248, 166, 68, 26, 153, 199, 37, 123, + 58, 100, 134, 216, 91, 5, 231, 185, + 140, 210, 48, 110, 237, 179, 81, 15, + 78, 16, 242, 172, 47, 113, 147, 205, + 17, 79, 173, 243, 112, 46, 204, 146, + 211, 141, 111, 49, 178, 236, 14, 80, + 175, 241, 19, 77, 206, 144, 114, 44, + 109, 51, 209, 143, 12, 82, 176, 238, + 50, 108, 142, 208, 83, 13, 239, 177, + 240, 174, 76, 18, 145, 207, 45, 115, + 202, 148, 118, 40, 171, 245, 23, 73, + 8, 86, 180, 234, 105, 55, 213, 139, + 87, 9, 235, 181, 54, 104, 138, 212, + 149, 203, 41, 119, 244, 170, 72, 22, + 233, 183, 85, 11, 136, 214, 52, 106, + 43, 117, 151, 201, 74, 20, 246, 168, + 116, 42, 200, 150, 21, 75, 169, 247, + 182, 232, 10, 84, 215, 137, 107, 53 +}; + +static void +write_gpio_data(int value ){ + if(value){ + /* Tristate */ + gpio_tristate(GPIO_EEDQ); + } + else{ + /* Drive 0 */ + gpio_clear(GPIO_EEDQ); + } +} + +static u8 make_new_crc( u8 Old_crc, u8 New_value ){ + /* Compute a new checksum with new byte, using previous checksum as input + See DS app note 17, understanding and using cyclic redundancy checks... + Also see DS2438, page 11 */ + return( crc_lookup[Old_crc ^ New_value ]); +} + +int ee_crc_ok( u8 *Buffer, int Len, u8 Crc ){ + /* Check if the checksum for this buffer is correct */ + u8 Curr_crc=0; + int i; + u8 *Curr_byte = Buffer; + + for(i=0;i<Len;i++){ + Curr_crc = make_new_crc( Curr_crc, *Curr_byte); + Curr_byte++; + } + E_DEBUG("Calculated CRC = 0x%x, read = 0x%x\n", Curr_crc, Crc); + + if(Curr_crc == Crc){ + /* Good */ + return(TRUE); + } + printk(KERN_ERR"EE checksum error, Calculated CRC = 0x%x, read = 0x%x\n", Curr_crc, Crc); + return(FALSE); +} + +static void +set_idle(void){ + /* Send idle and keep start time + Continous 1 is idle */ + WRITE_PORT(1); +} + + +static int +do_cpu_reset(void){ + /* Release reset and verify that chip responds with presence pulse */ + int Retries=0; + while(Retries<15){ + udelay(RESET_LOW_TIME); + + /* Send reset */ + WRITE_PORT(0); + udelay(RESET_LOW_TIME); + + /* Release reset */ + WRITE_PORT(1); + + /* Wait for EEPROM to drive output */ + udelay(PRESENCE_TIMEOUT); + if(!READ_PORT){ + /* Ok, EEPROM is driving a 0 */ + E_DEBUG("Presence detected\n"); + if(Retries){ + E_DEBUG("Retries %d\n",Retries); + } + /* Make sure chip releases pin */ + udelay(PRESENCE_LOW_TIME); + return 0; + } + Retries++; + } + + printk(KERN_ERR"eeprom did not respond when releasing reset\n"); + + /* Make sure chip releases pin */ + udelay(PRESENCE_LOW_TIME); + + /* Set to idle again */ + set_idle(); + + return(-EIO); +} + +static u8 +read_cpu_byte(void){ + /* Read a single byte from EEPROM + Read LSb first */ + int i; + int Value; + u8 Result=0; + u32 Flags; + + E_DEBUG("Reading byte\n"); + + for(i=0;i<8;i++){ + /* Small delay between pulses */ + udelay(1); + +#ifdef __KERNEL__ + /* Disable irq */ + save_flags(Flags); + cli(); +#endif + + /* Pull down pin short time to start read + See page 26 in data sheet */ + + WRITE_PORT(0); + udelay(READ_LOW); + WRITE_PORT(1); + + /* Wait for chip to drive pin */ + udelay(READ_TIMEOUT); + + Value = READ_PORT; + if(Value) + Value=1; + +#ifdef __KERNEL__ + /* Enable irq */ + restore_flags(Flags); +#endif + + /* Wait for chip to release pin */ + udelay(TOTAL_READ_LOW-READ_TIMEOUT); + + /* LSb first */ + Result|=Value<<i; + /* E_DEBUG("Read %d\n",Value); */ + + } + + E_DEBUG("Read byte 0x%x\n",Result); + + return(Result); +} + +static void +write_cpu_byte(u8 Byte){ + /* Write a single byte to EEPROM + Write LSb first */ + int i; + int Value; + u32 Flags; + + E_DEBUG("Writing byte 0x%x\n",Byte); + + for(i=0;i<8;i++){ + /* Small delay between pulses */ + udelay(1); + Value = Byte&1; + +#ifdef __KERNEL__ + /* Disable irq */ + save_flags(Flags); + cli(); +#endif + + /* Pull down pin short time for a 1, long time for a 0 + See page 26 in data sheet */ + + WRITE_PORT(0); + if(Value){ + /* Write a 1 */ + udelay(WRITE_1_LOW); + } + else{ + /* Write a 0 */ + udelay(WRITE_0_LOW); + } + + WRITE_PORT(1); + +#ifdef __KERNEL__ + /* Enable irq */ + restore_flags(Flags); +#endif + + if(Value) + /* Wait for chip to read the 1 */ + udelay(TOTAL_WRITE_LOW-WRITE_1_LOW); + + /* E_DEBUG("Wrote %d\n",Value); */ + Byte>>=1; + } +} + +int ee_do_cpu_command( u8 *Tx, int Tx_len, u8 *Rx, int Rx_len, int Send_skip ){ + /* Execute this command string, including + giving reset and setting to idle after command + if Rx_len is set, we read out data from EEPROM */ + int i; + + E_DEBUG("Command, Tx_len %d, Rx_len %d\n", Tx_len, Rx_len ); + + if(do_cpu_reset()){ + /* Failed! */ + return(-EIO); + } + + if(Send_skip) + /* Always send SKIP_ROM first to tell chip we are sending a command, + except when we read out rom data for chip */ + write_cpu_byte(SKIP_ROM); + + /* Always have Tx data */ + for(i=0;i<Tx_len;i++){ + write_cpu_byte(Tx[i]); + } + + if(Rx_len){ + for(i=0;i<Rx_len;i++){ + Rx[i]=read_cpu_byte(); + } + } + + set_idle(); + + E_DEBUG("Command done\n"); + + return(0); +} + +int ee_init_cpu_data(void){ + int i; + u8 Tx[10]; + + /* Leave it floting since altera is driving the same pin */ + set_idle(); + + /* Copy all User EEPROM data to scratchpad */ + for(i=0;i<USER_PAGES;i++){ + Tx[0]=RECALL_MEMORY; + Tx[1]=EE_USER_PAGE_0+i; + if(ee_do_cpu_command(Tx,2,NULL,0,TRUE)) return(-EIO); + } + + /* Make sure chip doesnt store measurements in NVRAM */ + Tx[0]=WRITE_SCRATCHPAD; + Tx[1]=0; /* Page */ + Tx[2]=9; + if(ee_do_cpu_command(Tx,3,NULL,0,TRUE)) return(-EIO); + + Tx[0]=COPY_SCRATCHPAD; + if(ee_do_cpu_command(Tx,2,NULL,0,TRUE)) return(-EIO); + + for(i=0;i<10;i++){ + udelay(1000); + } + + return(0); +} |