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authorpatacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3>2010-09-08 17:38:44 +0000
committerpatacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3>2010-09-08 17:38:44 +0000
commitf5072951cc0ddc165fea568a2733a19b51ed1cee (patch)
treece666d30296334e7635272e8f80c442dd11117bb /nuttx/configs/ea3131/README.txt
parent7aef1347d64241b4516a32aeb7dd7f9696aa75b4 (diff)
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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
Diffstat (limited to 'nuttx/configs/ea3131/README.txt')
-rwxr-xr-xnuttx/configs/ea3131/README.txt35
1 files changed, 34 insertions, 1 deletions
diff --git a/nuttx/configs/ea3131/README.txt b/nuttx/configs/ea3131/README.txt
index 2e3c1b874..556c4cb25 100755
--- a/nuttx/configs/ea3131/README.txt
+++ b/nuttx/configs/ea3131/README.txt
@@ -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