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Clean up the serial driver read and write routines.

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This commit is contained in:
Jonas 'Sortie' Termansen 2014-01-16 20:45:47 +01:00
parent a6603dffd9
commit 105278a500
1 changed files with 36 additions and 29 deletions
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65
kernel/com.cpp
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@ -24,6 +24,7 @@
#include <errno.h>
#include <sortix/fcntl.h>
#include <sortix/stat.h>
#include <sortix/kernel/descriptor.h>
@ -259,54 +260,60 @@ int DevCOMPort::sync(ioctx_t* /*ctx*/)
ssize_t DevCOMPort::read(ioctx_t* ctx, uint8_t* dest, size_t count)
{
if ( !count ) { return 0; }
if ( SSIZE_MAX < count ) { count = SSIZE_MAX; }
ScopedLock lock(&portlock);
while ( !(CPU::InPortB(port + LSR) & LSR_READY) )
if ( Signal::IsPending() )
for ( size_t i = 0; i < count; i++ )
{
int tries = 0;
while ( !IsLineReady(port) )
{
errno = EINTR;
return -1;
if ( ++tries < 10 )
continue;
if ( i )
return (ssize_t) i;
if ( ctx->dflags & O_NONBLOCK )
return errno = EWOULDBLOCK, -1;
if ( Signal::IsPending() )
return errno = EINTR, -1;
}
size_t sofar = 0;
do
{
if ( count <= sofar ) { break; }
uint8_t val = CPU::InPortB(port + RXR);
if ( !ctx->copy_to_dest(dest + sofar++, &val, sizeof(val)) )
return -1;
} while ( CPU::InPortB(port + LSR) & LSR_READY);
if ( !ctx->copy_to_dest(dest + i, &val, sizeof(val)) )
{
// TODO: The byte is lost in this case!
return i ? (ssize_t) i : -1;
}
}
return sofar;
return (ssize_t) count;
}
ssize_t DevCOMPort::write(ioctx_t* ctx, const uint8_t* src, size_t count)
{
if ( !count ) { return 0; }
if ( SSIZE_MAX < count ) { count = SSIZE_MAX; };
ScopedLock lock(&portlock);
while ( !(CPU::InPortB(port + LSR) & LSR_THRE) )
if ( Signal::IsPending() )
for ( size_t i = 0; i < count; i++ )
{
int tries = 0;
while ( !CanWriteByte(port) )
{
errno = EINTR;
return -1;
if ( ++tries < 10 )
continue;
if ( i )
return (ssize_t) i;
if ( ctx->dflags & O_NONBLOCK )
return errno = EWOULDBLOCK, -1;
if ( Signal::IsPending() )
return errno = EINTR, -1;
}
size_t sofar = 0;
do
{
if ( count <= sofar ) { break; }
uint8_t val;
if ( !ctx->copy_from_src(&val, src + sofar++, sizeof(val)) )
return -1;
if ( !ctx->copy_from_src(&val, src + i, sizeof(val)) )
return i ? (ssize_t) i : -1;
CPU::OutPortB(port + TXR, val);
} while ( CPU::InPortB(port + LSR) & LSR_THRE );
}
return sofar;
return (ssize_t) count;
}
#else