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/****************************************************************************
* configs/ea3131/src/up_fillpage.c
* arch/arm/src/board/up_fillpage.c
*
* Copyright (C) 2010 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/sched.h>
#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
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: up_fillpage()
*
* Description:
* After a page is allocated and mapped by up_allocpage(), the actual
* filling of the page with data from the non-volatile, must be performed
* by a separate call to the architecture-specific function, up_fillpage().
* This function is non-blocking, it will start an asynchronous page fill.
* The common paging logic will provide a callback function, pg_callback,
* that will be called when the page fill is finished (or an error occurs).
* This callback is assumed to occur from an interrupt level when the
* device driver completes the fill operation.
*
* NOTE 1: Allocating and filling a page is a two step process. up_allocpage()
* allocates the page, and up_fillpage() fills it with data from some non-
* volatile storage device. This distinction is made because up_allocpage()
* can probably be implemented in board-independent logic whereas up_fillpage()
* probably must be implemented as board-specific logic.
*
* NOTE 2: The initial mapping of vpage will be read-able, write-able,
* but non-cacheable. No special actions will be required of
* up_fillpage() in order to write into this allocated page. If the
* virtual address maps to a text region, however, this function should
* remap the region so that is is read/execute only. It should be made
* cache-able in any case.
* Input Parameters:
* tcb - A reference to the task control block of the task that needs to
* have a page fill. Architecture-specific logic can retrieve page
* fault information from the architecture-specific context
* information in this TCB to perform the fill.
* pg_callbck - The function to be called when the page fill is complete.
*
* Returned Value:
* This function will return zero (OK) if the page fill was successfully
* started (the result of the page fill is passed to the callback function
* as the result argument). A negated errno value may be returned if an
* error occurs. All errors, however, are fatal.
*
* NOTE: -EBUSY has a special meaning. It is used internally to mean that
* the callback function has not executed. Therefore, -EBUSY should
* never be provided in the result argument of pg_callback.
*
* Assumptions:
* - This function is called from the normal tasking context (but
* interrupts siabled). The implementation must take whatever actions
* are necessary to assure that the operation is safe within this context.
* - Upon return, the caller will sleep waiting for the page fill callback
* to occur. The callback function will perform the wakeup.
*
****************************************************************************/
#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);
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 /* CONFIG_PAGING_BLOCKINGFILL */
/************************************************************************************
* Name: lpc313x_pginitialize
*
* Description:
* Set up mass storage device to support on demand paging.
*
************************************************************************************/
void weak_function lpc313x_pginitialize(void)
{
/* This initialization does nothing in this example setup. But this function is
* where you might, for example:
*
* - Initialize and configure a mass storage device to support on-demand paging.
* This might be, perhaps an SD card or NAND memory. An SPI FLASH would probably
* already have been configured by lpc313x_spiinitialize(void);
* - Set up resources to support up_fillpage() operation. For example, perhaps the
* the text image is stored in a named binary file. In this case, the virtual
* text addresses might map to offsets into that file.
* - 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 */
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