Flash bound checking fails if "upper (0xffffffff)" flash mapping

[sebastien Couret <sebastien dot couret at elios-informatique dot fr>]

I have ran into a particular problem with the flash. 
It's about flash address bound checking.
This problem only happens if the two following conditions are met :

 - Assert are activated (CYG_INFRA_DEBUG set)
 - Upper flash address is set to 0xffffffff 

What happens is that 'flash_hwr_init()' (which is implemented differently for 
each flash hardware) sets flash_info.end to zero (0xffffffff+1 !))

As a result , in io/flash/current/src/flashiodev.c , following check fails !
(flashend=0 and endpos>0 ), so flash access is always refused !

#ifdef CYGPKG_INFRA_DEBUG // don't bother checking this all the time
    char *endpos = startpos + *len - 1;
    char *flashend = MIN( (char *)flash_info.end, dev->end);
    if ( startpos < dev->start )
        return -EINVAL;
    if ( endpos > flashend )
        return -EINVAL;
#endif

May be the better corrective will be to change the way of computing 
flash_info.end (by just substracting one) in each hardware flash driver.

But it's quicker to change directly flashiodev.c.
Here 's a patch :

 diff -a -w -r -u io/flash/current/src/v1.7/ io/flash/current/src/flashiodev.c
--- io/flash/current/src/v1.7/flashiodev.c      Thu Apr 22 11:31:55 2004
+++ io/flash/current/src/flashiodev.c   Mon Apr 19 18:47:35 2004
@@ -126,7 +126,7 @@

 #ifdef CYGPKG_INFRA_DEBUG // don't bother checking this all the time
     char *endpos = startpos + *len - 1;
-    char *flashend = MIN( (char *)flash_info.end, dev->end);
+    char *flashend = MIN( (char *)flash_info.end - 1, dev->end);
     if ( startpos < dev->start )
         return -EINVAL;
     if ( endpos > flashend )
@@ -154,7 +154,7 @@

 #ifdef CYGPKG_INFRA_DEBUG // don't bother checking this all the time
     char *endpos = startpos + *len - 1;
-    char *flashend = MIN( (char *)flash_info.end, dev->end);
+    char *flashend = MIN( (char *)flash_info.end - 1, dev->end);
     if ( startpos < dev->start )
         return -EINVAL;
     if ( endpos > flashend )
@@ -188,7 +188,7 @@

 #ifdef CYGPKG_INFRA_DEBUG // don't bother checking this all the time
             char *endpos = startpos + e->len - 1;
-                   char *flashend = MIN( (char *)flash_info.end, dev->end);
+                   char *flashend = MIN( (char *)flash_info.end - 1, 
dev->end);
                        if ( startpos < dev->start )
                 return -EINVAL;
             if ( endpos > flashend )
@@ -218,7 +218,7 @@
             (cyg_io_flash_getconfig_blocksize_t *)buf;
 #ifdef CYGPKG_INFRA_DEBUG // don't bother checking this all the time
        char *startpos = dev->start + b->offset;
-           char *flashend = MIN( (char *)flash_info.end, dev->end);
+           char *flashend = MIN( (char *)(flash_info.end) - 1, dev->end);

         if ( startpos < dev->start )
             return -EINVAL;
@@ -244,8 +244,10 @@
                        const void* buf,
                        cyg_uint32* len)
 {
+#ifdef CYGNUM_IO_FLASH_BLOCK_CFG_FIS_1
        struct cyg_devtab_entry *tab = (struct cyg_devtab_entry *)handle;
        struct flashiodev_priv_t *dev = (struct flashiodev_priv_t *)tab->priv;
+#endif

     switch (key) {
 #ifdef CYGNUM_IO_FLASH_BLOCK_CFG_FIS_1


And the Changelog entry :


2004-04-22 ?Sebastien Couret ?<sebastien.couret@elios-informatique.com>

? ? ? ? * src/flashiodev.c: Modified flash upper bound checking. (substracted 
one)