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Implement SD-based paging for EA3131 

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@2931 42af7a65-404d-4744-a932-0658087f49c3
This commit is contained in:
patacongo 2010-09-08 17:38:44 +00:00
parent 60961c2573
commit ad08a8d4bc
4 changed files with 135 additions and 3 deletions
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5
configs/README.txt
View File

@ -401,6 +401,11 @@ defconfig -- This is a configuration file similar to the Linux
page table entry to use for the vector mapping.
CONFIG_PAGING_VECL2VADDR - This is the virtual address of the L2
page table entry to use for the vector mapping.
CONFIG_PAGING_BINPATH - If CONFIG_PAGING_BINPATH is defined, then it
is the full path to a file on a mounted file system that contains
a binary image of the NuttX executable. Pages will be filled by
reading from offsets into this file that correspond to virtual
fault addresses.
The following can be used to disable categories of APIs supported
by the OS. If the compiler supports weak functions, then it

35
configs/ea3131/README.txt
View File

@ -416,8 +416,41 @@ On-Demand Paging
The references and issues related to this are discussed in (2)
and (3) above.
Alternative:
------------
I have implemented an alternative within configs/ea3131/src/up_fillpage.c
which is probably only useful for testing. Here is the usage module
for this alternative
1. Place the nuttx.bin file on an SD card.
2. Insert the SD card prior to booting
3. In up_fillpage(), use the virtual miss address (minus the virtual
base address) as an offset into the nuttx.bin file, and read the
required page from that offset in the nuttx.bin file:
off_t offset = (off_t)vpage - PG_LOCKED_VBASE;
off_t pos = lseek(fd, offset, SEEK_SET);
if (pos != (off_t)-1)
{
int ret = read(fd, vpage, PAGESIZE);
}
In this way, the paging implementation can do on-demand paging
from an image file on the SD card. Problems/issues with this
approach probably make it only useful for testing:
1. You would still have to boot the locked section over serial or
using a bootloader -- it is not clear how the power up boot
would occur. For testing, the nuttx.bin file could be both
provided on the SD card and loaded over serial.
2. If the SD card is not in place, the system will crash.
3. This means that all of the file system logic and FAT file
system would have to reside in the locked text region.
ARM/EA3131-specific Configuration Options
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
CONFIG_ARCH - Identifies the arch/ subdirectory. This should
be set to:
@ -500,7 +533,7 @@ ARM/EA3131-specific Configuration Options
CONFIG_LPC313X_MCI, CONFIG_LPC313X_SPI, CONFIG_LPC313X_UART
xernal memory available on the board (see also CONFIG_MM_REGIONS)
External memory available on the board (see also CONFIG_MM_REGIONS)
CONFIG_LPC313X_EXTSRAM0 - Select if external SRAM0 is present
CONFIG_LPC313X_EXTSRAM0HEAP - Select if external SRAM0 should be

1
configs/ea3131/locked/mklocked.sh
View File

@ -86,6 +86,7 @@ function checkzero () {
echo "n"
fi
}
############################################################################
# Interrupt Handlers
############################################################################

97
configs/ea3131/src/up_fillpage.c
View File

@ -47,15 +47,38 @@
#include <nuttx/page.h>
#ifdef CONFIG_PAGING
#ifdef CONFIG_PAGING_BINPATH
# include <sys/stat.h>
# include <sys/types.h>
# include <stdbool.h>
# include <unistd.h>
# include <fcntl.h>
#endif
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
#ifdef CONFIG_PAGING_BINPATH
struct pg_source_s
{
bool initialized; /* TRUE: we are initialized */
int fd; /* File descriptor of the nuttx.bin file */
};
#endif
/****************************************************************************
* Private Data
****************************************************************************/
#ifdef CONFIG_PAGING_BINPATH
static struct pg_source_s g_pgsrc;
#endif
/****************************************************************************
* Private Functions
****************************************************************************/
@ -117,20 +140,80 @@
****************************************************************************/
#ifdef CONFIG_PAGING_BLOCKINGFILL
/* Version 1: Supports blocking fill operations */
int up_fillpage(FAR _TCB *tcb, FAR void *vpage)
{
#ifdef CONFIG_PAGING_BINPATH
ssize_t nbytes;
off_t offset;
off_t pos;
#endif
pglldbg("TCB: %p vpage: %p far: %08x\n", tcb, vpage, tcb->xcp.far);
DEBUGASSERT(tcb->xcp.far >= PG_PAGED_VBASE && tcb->xcp.far < PG_PAGED_VEND);
/* If BINPATH is defined, then it is the full path to a file on a mounted file
* system. In this caseinitialization will be deferred until the first
* time that up_fillpage() is called. Are we initialized?
*/
#ifdef CONFIG_PAGING_BINPATH
if (!g_pgsrc.initialized)
{
/* Open the selected path for read-only access */
g_pgsrc.fd = open(CONFIG_PAGING_BINPATH, O_RDONLY);
DEBUGASSERT(g_pgsrc.fd >= 0);
g_pgsrc.initialized = true;
}
/* Create an offset into the binary image that corresponds to the
* virtual address. File offset 0 corresponds to PG_LOCKED_VBASE.
*/
offset = (off_t)vpage - PG_LOCKED_VBASE;
/* Seek to that position */
pos = lseek(g_pgsrc.fd, offset, SEEK_SET);
DEBUGASSERT(pos != (off_t)-1);
/* And read the page data from that offset */
nbytes = read(g_pgsrc.fd, vpage, PAGESIZE);
DEBUGASSERT(nbytes == PAGESIZE);
return OK;
#else /* CONFIG_PAGING_BINPATH */
# warning "Not implemented"
return -ENOSYS;
#endif /* CONFIG_PAGING_BINPATH */
}
#else
/* Version 2: Supports non-blocking, asynchronous fill operations */
int up_fillpage(FAR _TCB *tcb, FAR void *vpage, up_pgcallback_t pg_callback)
{
pglldbg("TCB: %p vpage: %d far: %08x\n", tcb, vpage, tcb->xcp.far);
# warning "Not implemented"
DEBUGASSERT(tcb->xcp.far >= PG_PAGED_VBASE && tcb->xcp.far < PG_PAGED_VEND);
#ifdef CONFIG_PAGING_BINPATH
# error "File system-based paging must always be implemented with blocking calls"
#else
# warning "Not implemented"
#endif
return -ENOSYS;
}
#endif
#endif /* CONFIG_PAGING_BLOCKINGFILL */
/************************************************************************************
* Name: lpc313x_pginitialize
@ -154,6 +237,16 @@ void weak_function lpc313x_pginitialize(void)
* - Do whatever else is necessary to make up_fillpage() ready for the first time
* that it is called.
*/
#ifdef CONFIG_PAGING_BINPATH
/* If BINPATH is defined, then it is the full path to a file on a mounted file
* system. However, in this case, initialization will involve some higher level
* file system operations. Since this function is called from a low level (before
* os_start() is even called), it may not be possible to perform file system
* operations yet. Therefore, initialization will be deferred until the first
* time that up_fillpage() is called.
*/
#endif
}
#endif /* CONFIG_PAGING */