/****************************************************************************** *! *! Implements an interface for i2c compatible eeproms to run under linux. *! Supports 2k, 8k(?) and 16k. Uses adaptive timing adjustents by *! Johan.Adolfsson@axis.com *! *! Probing results: *! 8k or not is detected (the assumes 2k or 16k) *! 2k or 16k detected using test reads and writes. *! *!------------------------------------------------------------------------ *! HISTORY *! *! DATE NAME CHANGES *! ---- ---- ------- *! Aug 28 1999 Edgar Iglesias Initial Version *! Aug 31 1999 Edgar Iglesias Allow simultaneous users. *! Sep 03 1999 Edgar Iglesias Updated probe. *! Sep 03 1999 Edgar Iglesias Added bail-out stuff if we get interrupted *! in the spin-lock. *! *! $Log: eeprom.c,v $ *! Revision 1.12 2003/04/09 08:31:14 pkj *! Typo correction (taken from Linux 2.5). *! *! Revision 1.11 2003/02/12 20:43:46 johana *! Previous checkin removed beginning of comment. *! *! Revision 1.10 2003/02/10 07:18:20 starvik *! Removed misplaced ; *! *! Revision 1.9 2003/01/22 06:54:46 starvik *! Fixed warnings issued by GCC 3.2.1 *! *! Revision 1.8 2001/06/15 13:24:29 jonashg *! * Added verification of pointers from userspace in read and write. *! * Made busy counter volatile. *! * Added define for inital write delay. *! * Removed warnings by using loff_t instead of unsigned long. *! *! Revision 1.7 2001/06/14 15:26:54 jonashg *! Removed test because condition is always true. *! *! Revision 1.6 2001/06/14 15:18:20 jonashg *! Kb -> kB (makes quite a difference if you don't know if you have 2k or 16k). *! *! Revision 1.5 2001/06/14 14:39:51 jonashg *! Forgot to use name when registering the driver. *! *! Revision 1.4 2001/06/14 14:35:47 jonashg *! * Gave driver a name and used it in printk's. *! * Cleanup. *! *! Revision 1.3 2001/03/19 16:04:46 markusl *! Fixed init of fops struct *! *! Revision 1.2 2001/03/19 10:35:07 markusl *! 2.4 port of eeprom driver *! *! Revision 1.8 2000/05/18 10:42:25 edgar *! Make sure to end write cycle on _every_ write *! *! Revision 1.7 2000/01/17 17:41:01 johana *! Adjusted probing and return -ENOSPC when writing outside EEPROM *! *! Revision 1.6 2000/01/17 15:50:36 johana *! Added adaptive timing adjustments and fixed autoprobing for 2k and 16k(?) *! EEPROMs *! *! Revision 1.5 1999/09/03 15:07:37 edgar *! Added bail-out check to the spinlock *! *! Revision 1.4 1999/09/03 12:11:17 bjornw *! Proper atomicity (need to use spinlocks, not if's). users -> busy. *! *! *! (c) 1999 Axis Communications AB, Lund, Sweden *!*****************************************************************************/ #include #include #include #include #include #include #include #include "i2c.h" #define D(x) /* If we should use adaptive timing or not: */ //#define EEPROM_ADAPTIVE_TIMING #define EEPROM_MAJOR_NR 122 /* use a LOCAL/EXPERIMENTAL major for now */ #define EEPROM_MINOR_NR 0 /* Empirical sane initial value of the delay, the value will be adapted to * what the chip needs when using EEPROM_ADAPTIVE_TIMING. */ #define INITIAL_WRITEDELAY_US 4000 #define MAX_WRITEDELAY_US 10000 /* 10 ms according to spec for 2KB EEPROM */ /* This one defines how many times to try when eeprom fails. */ #define EEPROM_RETRIES 10 #define EEPROM_2KB (2 * 1024) /*#define EEPROM_4KB (4 * 1024)*/ /* Exists but not used in Axis products */ #define EEPROM_8KB (8 * 1024 - 1 ) /* Last byte has write protection bit */ #define EEPROM_16KB (16 * 1024) #define i2c_delay(x) udelay(x) /* * This structure describes the attached eeprom chip. * The values are probed for. */ struct eeprom_type { unsigned long size; unsigned long sequential_write_pagesize; unsigned char select_cmd; unsigned long usec_delay_writecycles; /* Min time between write cycles (up to 10ms for some models) */ unsigned long usec_delay_step; /* For adaptive algorithm */ int adapt_state; /* 1 = To high , 0 = Even, -1 = To low */ /* this one is to keep the read/write operations atomic */ wait_queue_head_t wait_q; volatile int busy; int retry_cnt_addr; /* Used to keep track of number of retries for adaptive timing adjustments */ int retry_cnt_read; }; static int eeprom_open(struct inode * inode, struct file * file); static loff_t eeprom_lseek(struct file * file, loff_t offset, int orig); static ssize_t eeprom_read(struct file * file, char * buf, size_t count, loff_t *off); static ssize_t eeprom_write(struct file * file, const char * buf, size_t count, loff_t *off); static int eeprom_close(struct inode * inode, struct file * file); static int eeprom_address(unsigned long addr); static int read_from_eeprom(char * buf, int count); static int eeprom_write_buf(loff_t addr, const char * buf, int count); static int eeprom_read_buf(loff_t addr, char * buf, int count); static void eeprom_disable_write_protect(void); static const char eeprom_name[] = "eeprom"; /* chip description */ static struct eeprom_type eeprom; /* This is the exported file-operations structure for this device. */ struct file_operations eeprom_fops = { llseek: eeprom_lseek, read: eeprom_read, write: eeprom_write, open: eeprom_open, release: eeprom_close }; /* eeprom init call. Probes for different eeprom models. */ int __init eeprom_init(void) { init_waitqueue_head(&eeprom.wait_q); eeprom.busy = 0; #if CONFIG_ETRAX_I2C_EEPROM_PROBE #define EETEXT "Found" #else #define EETEXT "Assuming" #endif if (register_chrdev(EEPROM_MAJOR_NR, eeprom_name, &eeprom_fops)) { printk(KERN_INFO "%s: unable to get major %d for eeprom device\n", eeprom_name, EEPROM_MAJOR_NR); return -1; } printk("EEPROM char device v0.3, (c) 2000 Axis Communications AB\n"); /* * Note: Most of this probing method was taken from the printserver (5470e) * codebase. It did not contain a way of finding the 16kB chips * (M24128 or variants). The method used here might not work * for all models. If you encounter problems the easiest way * is probably to define your model within #ifdef's, and hard- * code it. */ eeprom.size = 0; eeprom.usec_delay_writecycles = INITIAL_WRITEDELAY_US; eeprom.usec_delay_step = 128; eeprom.adapt_state = 0; #if CONFIG_ETRAX_I2C_EEPROM_PROBE i2c_start(); i2c_outbyte(0x80); if(!i2c_getack()) { /* It's not 8k.. */ int success = 0; unsigned char buf_2k_start[16]; /* Im not sure this will work... :) */ /* assume 2kB, if failure go for 16kB */ /* Test with 16kB settings.. */ /* If it's a 2kB EEPROM and we address it outside it's range * it will mirror the address space: * 1. We read two locations (that are mirrored), * if the content differs * it's a 16kB EEPROM. * 2. if it doesn't differ - write different value to one of the locations, * check the other - if content still is the same it's a 2k EEPROM, * restore original data. */ #define LOC1 8 #define LOC2 (0x1fb) /*1fb, 3ed, 5df, 7d1 */ /* 2k settings */ i2c_stop(); eeprom.size = EEPROM_2KB; eeprom.select_cmd = 0xA0; eeprom.sequential_write_pagesize = 16; if( eeprom_read_buf( 0, buf_2k_start, 16 ) == 16 ) { D(printk("2k start: '%16.16s'\n", buf_2k_start)); } else { printk(KERN_INFO "%s: Failed to read in 2k mode!\n", eeprom_name); } /* 16k settings */ eeprom.size = EEPROM_16KB; eeprom.select_cmd = 0xA0; eeprom.sequential_write_pagesize = 64; { unsigned char loc1[4], loc2[4], tmp[4]; if( eeprom_read_buf(LOC2, loc2, 4) == 4) { if( eeprom_read_buf(LOC1, loc1, 4) == 4) { D(printk("0 loc1: (%i) '%4.4s' loc2 (%i) '%4.4s'\n", LOC1, loc1, LOC2, loc2)); #if 0 if (memcmp(loc1, loc2, 4) != 0 ) { /* It's 16k */ printk(KERN_INFO "%s: 16k detected in step 1\n", eeprom_name); eeprom.size = EEPROM_16KB; success = 1; } else #endif { /* Do step 2 check */ /* Invert value */ loc1[0] = ~loc1[0]; if (eeprom_write_buf(LOC1, loc1, 1) == 1) { /* If 2k EEPROM this write will actually write 10 bytes * from pos 0 */ D(printk("1 loc1: (%i) '%4.4s' loc2 (%i) '%4.4s'\n", LOC1, loc1, LOC2, loc2)); if( eeprom_read_buf(LOC1, tmp, 4) == 4) { D(printk("2 loc1: (%i) '%4.4s' tmp '%4.4s'\n", LOC1, loc1, tmp)); if (memcmp(loc1, tmp, 4) != 0 ) { printk(KERN_INFO "%s: read and write differs! Not 16kB\n", eeprom_name); loc1[0] = ~loc1[0]; if (eeprom_write_buf(LOC1, loc1, 1) == 1) { success = 1; } else { printk(KERN_INFO "%s: Restore 2k failed during probe," " EEPROM might be corrupt!\n", eeprom_name); } i2c_stop(); /* Go to 2k mode and write original data */ eeprom.size = EEPROM_2KB; eeprom.select_cmd = 0xA0; eeprom.sequential_write_pagesize = 16; if( eeprom_write_buf(0, buf_2k_start, 16) == 16) { } else { printk(KERN_INFO "%s: Failed to write back 2k start!\n", eeprom_name); } eeprom.size = EEPROM_2KB; } } if(!success) { if( eeprom_read_buf(LOC2, loc2, 1) == 1) { D(printk("0 loc1: (%i) '%4.4s' loc2 (%i) '%4.4s'\n", LOC1, loc1, LOC2, loc2)); if (memcmp(loc1, loc2, 4) == 0 ) { /* Data the same, must be mirrored -> 2k */ /* Restore data */ printk(KERN_INFO "%s: 2k detected in step 2\n", eeprom_name); loc1[0] = ~loc1[0]; if (eeprom_write_buf(LOC1, loc1, 1) == 1) { success = 1; } else { printk(KERN_INFO "%s: Restore 2k failed during probe," " EEPROM might be corrupt!\n", eeprom_name); } eeprom.size = EEPROM_2KB; } else { printk(KERN_INFO "%s: 16k detected in step 2\n", eeprom_name); loc1[0] = ~loc1[0]; /* Data differs, assume 16k */ /* Restore data */ if (eeprom_write_buf(LOC1, loc1, 1) == 1) { success = 1; } else { printk(KERN_INFO "%s: Restore 16k failed during probe," " EEPROM might be corrupt!\n", eeprom_name); } eeprom.size = EEPROM_16KB; } } } } } /* read LOC1 */ } /* address LOC1 */ if (!success) { printk(KERN_INFO "%s: Probing failed!, using 2KB!\n", eeprom_name); eeprom.size = EEPROM_2KB; } } /* read */ } } else { i2c_outbyte(0x00); if(!i2c_getack()) { /* No 8k */ eeprom.size = EEPROM_2KB; } else { i2c_start(); i2c_outbyte(0x81); if (!i2c_getack()) { eeprom.size = EEPROM_2KB; } else { /* It's a 8kB */ i2c_inbyte(); eeprom.size = EEPROM_8KB; } } } i2c_stop(); #elif defined(CONFIG_ETRAX_I2C_EEPROM_16KB) eeprom.size = EEPROM_16KB; #elif defined(CONFIG_ETRAX_I2C_EEPROM_8KB) eeprom.size = EEPROM_8KB; #elif defined(CONFIG_ETRAX_I2C_EEPROM_2KB) eeprom.size = EEPROM_2KB; #endif switch(eeprom.size) { case (EEPROM_2KB): printk("%s: " EETEXT " i2c compatible 2kB eeprom.\n", eeprom_name); eeprom.sequential_write_pagesize = 16; eeprom.select_cmd = 0xA0; break; case (EEPROM_8KB): printk("%s: " EETEXT " i2c compatible 8kB eeprom.\n", eeprom_name); eeprom.sequential_write_pagesize = 16; eeprom.select_cmd = 0x80; break; case (EEPROM_16KB): printk("%s: " EETEXT " i2c compatible 16kB eeprom.\n", eeprom_name); eeprom.sequential_write_pagesize = 64; eeprom.select_cmd = 0xA0; break; default: eeprom.size = 0; printk("%s: Did not find a supported eeprom\n", eeprom_name); break; } eeprom_disable_write_protect(); return 0; } /* Opens the device. */ static int eeprom_open(struct inode * inode, struct file * file) { if(MINOR(inode->i_rdev) != EEPROM_MINOR_NR) return -ENXIO; if(MAJOR(inode->i_rdev) != EEPROM_MAJOR_NR) return -ENXIO; if( eeprom.size > 0 ) { /* OK */ return 0; } /* No EEprom found */ return -EFAULT; } /* Changes the current file position. */ static loff_t eeprom_lseek(struct file * file, loff_t offset, int orig) { /* * orig 0: position from begning of eeprom * orig 1: relative from current position * orig 2: position from last eeprom address */ switch (orig) { case 0: file->f_pos = offset; break; case 1: file->f_pos += offset; break; case 2: file->f_pos = eeprom.size - offset; break; default: return -EINVAL; } /* truncate position */ if (file->f_pos < 0) { file->f_pos = 0; return(-EOVERFLOW); } if (file->f_pos >= eeprom.size) { file->f_pos = eeprom.size - 1; return(-EOVERFLOW); } return ( file->f_pos ); } /* Reads data from eeprom. */ static int eeprom_read_buf(loff_t addr, char * buf, int count) { struct file f; f.f_pos = addr; return eeprom_read(&f, buf, count, &addr); } /* Reads data from eeprom. */ static ssize_t eeprom_read(struct file * file, char * buf, size_t count, loff_t *off) { int read=0; unsigned long p = *off; unsigned char page; if(p >= eeprom.size) /* Address i 0 - (size-1) */ { return -EFAULT; } while(eeprom.busy) { interruptible_sleep_on(&eeprom.wait_q); /* bail out if we get interrupted */ if (signal_pending(current)) return -EINTR; } eeprom.busy++; page = (unsigned char) (p >> 8); if(!eeprom_address(p)) { printk(KERN_INFO "%s: Read failed to address the eeprom: " "0x%08lX (%li) page: %i\n", eeprom_name, p, p, page); i2c_stop(); /* don't forget to wake them up */ eeprom.busy--; wake_up_interruptible(&eeprom.wait_q); return -EFAULT; } if(count > eeprom.size - p) { /* truncate count */ count = eeprom.size - p; } /* stop dummy write op and initiate the read op */ i2c_start(); /* special case for small eeproms */ if(eeprom.size < EEPROM_16KB) { i2c_outbyte( eeprom.select_cmd | 1 | (page << 1) ); } /* go on with the actual read */ read = read_from_eeprom( buf, count); if(read > 0) { *off = p + read; } eeprom.busy--; wake_up_interruptible(&eeprom.wait_q); return read; } /* Writes data to eeprom. */ static int eeprom_write_buf(loff_t addr, const char * buf, int count) { struct file f; f.f_pos = addr; return eeprom_write(&f, buf, count, &addr); } /* Writes data to eeprom. */ static ssize_t eeprom_write(struct file * file, const char * buf, size_t count, loff_t *off) { int i, written, restart=1; unsigned long p; if (verify_area(VERIFY_READ, buf, count)) { return -EFAULT; } while(eeprom.busy) { interruptible_sleep_on(&eeprom.wait_q); /* bail out if we get interrupted */ if (signal_pending(current)) return -EINTR; } eeprom.busy++; for(i = 0; (i < EEPROM_RETRIES) && (restart > 0); i++) { restart = 0; written = 0; p = *off; while( (written < count) && (p < eeprom.size)) { /* address the eeprom */ if(!eeprom_address(p)) { printk(KERN_INFO "%s: Write failed to address the eeprom: " "0x%08lX (%li) \n", eeprom_name, p, p); i2c_stop(); /* don't forget to wake them up */ eeprom.busy--; wake_up_interruptible(&eeprom.wait_q); return -EFAULT; } #ifdef EEPROM_ADAPTIVE_TIMING /* Adaptive algorithm to adjust timing */ if (eeprom.retry_cnt_addr > 0) { /* To Low now */ D(printk(">D=%i d=%i\n", eeprom.usec_delay_writecycles, eeprom.usec_delay_step)); if (eeprom.usec_delay_step < 4) { eeprom.usec_delay_step++; eeprom.usec_delay_writecycles += eeprom.usec_delay_step; } else { if (eeprom.adapt_state > 0) { /* To Low before */ eeprom.usec_delay_step *= 2; if (eeprom.usec_delay_step > 2) { eeprom.usec_delay_step--; } eeprom.usec_delay_writecycles += eeprom.usec_delay_step; } else if (eeprom.adapt_state < 0) { /* To High before (toggle dir) */ eeprom.usec_delay_writecycles += eeprom.usec_delay_step; if (eeprom.usec_delay_step > 1) { eeprom.usec_delay_step /= 2; eeprom.usec_delay_step--; } } } eeprom.adapt_state = 1; } else { /* To High (or good) now */ D(printk(" 1) { eeprom.usec_delay_step *= 2; eeprom.usec_delay_step--; if (eeprom.usec_delay_writecycles > eeprom.usec_delay_step) { eeprom.usec_delay_writecycles -= eeprom.usec_delay_step; } } } else if (eeprom.adapt_state > 0) { /* To Low before (toggle dir) */ if (eeprom.usec_delay_writecycles > eeprom.usec_delay_step) { eeprom.usec_delay_writecycles -= eeprom.usec_delay_step; } if (eeprom.usec_delay_step > 1) { eeprom.usec_delay_step /= 2; eeprom.usec_delay_step--; } eeprom.adapt_state = -1; } if (eeprom.adapt_state > -100) { eeprom.adapt_state--; } else { /* Restart adaption */ D(printk("#Restart\n")); eeprom.usec_delay_step++; } } #endif /* EEPROM_ADAPTIVE_TIMING */ /* write until we hit a page boundary or count */ do { i2c_outbyte(buf[written]); if(!i2c_getack()) { restart=1; printk(KERN_INFO "%s: write error, retrying. %d\n", eeprom_name, i); i2c_stop(); break; } written++; p++; } while( written < count && ( p % eeprom.sequential_write_pagesize )); /* end write cycle */ i2c_stop(); i2c_delay(eeprom.usec_delay_writecycles); } /* while */ } /* for */ eeprom.busy--; wake_up_interruptible(&eeprom.wait_q); if (written == 0 && p >= eeprom.size){ return -ENOSPC; } *off = p; return written; } /* Closes the device. */ static int eeprom_close(struct inode * inode, struct file * file) { /* do nothing for now */ return 0; } /* Sets the current address of the eeprom. */ static int eeprom_address(unsigned long addr) { int i; unsigned char page, offset; page = (unsigned char) (addr >> 8); offset = (unsigned char) addr; for(i = 0; i < EEPROM_RETRIES; i++) { /* start a dummy write for addressing */ i2c_start(); if(eeprom.size == EEPROM_16KB) { i2c_outbyte( eeprom.select_cmd ); i2c_getack(); i2c_outbyte(page); } else { i2c_outbyte( eeprom.select_cmd | (page << 1) ); } if(!i2c_getack()) { /* retry */ i2c_stop(); /* Must have a delay here.. 500 works, >50, 100->works 5th time*/ i2c_delay(MAX_WRITEDELAY_US / EEPROM_RETRIES * i); /* The chip needs up to 10 ms from write stop to next start */ } else { i2c_outbyte(offset); if(!i2c_getack()) { /* retry */ i2c_stop(); } else break; } } eeprom.retry_cnt_addr = i; D(printk("%i\n", eeprom.retry_cnt_addr)); if(eeprom.retry_cnt_addr == EEPROM_RETRIES) { /* failed */ return 0; } return 1; } /* Reads from current address. */ static int read_from_eeprom(char * buf, int count) { int i, read=0; for(i = 0; i < EEPROM_RETRIES; i++) { if(eeprom.size == EEPROM_16KB) { i2c_outbyte( eeprom.select_cmd | 1 ); } if(i2c_getack()) { break; } } if(i == EEPROM_RETRIES) { printk(KERN_INFO "%s: failed to read from eeprom\n", eeprom_name); i2c_stop(); return -EFAULT; } while( (read < count)) { if (put_user(i2c_inbyte(), &buf[read++])) { i2c_stop(); return -EFAULT; } /* * make sure we don't ack last byte or you will get very strange * results! */ if(read < count) { i2c_sendack(); } } /* stop the operation */ i2c_stop(); return read; } /* Disables write protection if applicable. */ #define DBP_SAVE(x) #define ax_printf printk static void eeprom_disable_write_protect(void) { /* Disable write protect */ if (eeprom.size == EEPROM_8KB) { /* Step 1 Set WEL = 1 (write 00000010 to address 1FFFh */ i2c_start(); i2c_outbyte(0xbe); if(!i2c_getack()) { DBP_SAVE(ax_printf("Get ack returns false\n")); } i2c_outbyte(0xFF); if(!i2c_getack()) { DBP_SAVE(ax_printf("Get ack returns false 2\n")); } i2c_outbyte(0x02); if(!i2c_getack()) { DBP_SAVE(ax_printf("Get ack returns false 3\n")); } i2c_stop(); i2c_delay(1000); /* Step 2 Set RWEL = 1 (write 00000110 to address 1FFFh */ i2c_start(); i2c_outbyte(0xbe); if(!i2c_getack()) { DBP_SAVE(ax_printf("Get ack returns false 55\n")); } i2c_outbyte(0xFF); if(!i2c_getack()) { DBP_SAVE(ax_printf("Get ack returns false 52\n")); } i2c_outbyte(0x06); if(!i2c_getack()) { DBP_SAVE(ax_printf("Get ack returns false 53\n")); } i2c_stop(); /* Step 3 Set BP1, BP0, and/or WPEN bits (write 00000110 to address 1FFFh */ i2c_start(); i2c_outbyte(0xbe); if(!i2c_getack()) { DBP_SAVE(ax_printf("Get ack returns false 56\n")); } i2c_outbyte(0xFF); if(!i2c_getack()) { DBP_SAVE(ax_printf("Get ack returns false 57\n")); } i2c_outbyte(0x06); if(!i2c_getack()) { DBP_SAVE(ax_printf("Get ack returns false 58\n")); } i2c_stop(); /* Write protect disabled */ } } module_init(eeprom_init);