of data for one 512-byte page or 2 256-byte pages. There is no check
for bad blocks.
- nand read.raw addr ofs|partition
- Read page from `ofs' in NAND flash to `addr'. This reads the raw page,
- so ECC is avoided and the OOB area is read as well.
-
- nand write.raw addr ofs|partition
- Write page from `addr' to `ofs' in NAND flash. This writes the raw page,
- so ECC is avoided and the OOB area is written as well, making the whole
- page written as-is.
+ nand read.raw addr ofs|partition [count]
+ nand write.raw addr ofs|partition [count]
+ Read or write one or more pages at "ofs" in NAND flash, from or to
+ "addr" in memory. This is a raw access, so ECC is avoided and the
+ OOB area is transferred as well. If count is absent, it is assumed
+ to be one page. As with .yaffs2 accesses, the data is formatted as
+ a packed sequence of "data, oob, data, oob, ..." -- no alignment of
+ individual pages is maintained.
Configuration Options:
CONFIG_SYS_NAND_MAX_CHIPS
The maximum number of NAND chips per device to be supported.
+ CONFIG_SYS_NAND_SELF_INIT
+ Traditionally, glue code in drivers/mtd/nand/nand.c has driven
+ the initialization process -- it provides the mtd and nand
+ structs, calls a board init function for a specific device,
+ calls nand_scan(), and registers with mtd.
+
+ This arrangement does not provide drivers with the flexibility to
+ run code between nand_scan_ident() and nand_scan_tail(), or other
+ deviations from the "normal" flow.
+
+ If a board defines CONFIG_SYS_NAND_SELF_INIT, drivers/mtd/nand/nand.c
+ will make one call to board_nand_init(), with no arguments. That
+ function is responsible for calling a driver init function for
+ each NAND device on the board, that performs all initialization
+ tasks except setting mtd->name, and registering with the rest of
+ U-Boot. Those last tasks are accomplished by calling nand_register()
+ on the new mtd device.
+
+ Example of new init to be added to the end of an existing driver
+ init:
+
+ /*
+ * devnum is the device number to be used in nand commands
+ * and in mtd->name. Must be less than
+ * CONFIG_SYS_NAND_MAX_DEVICE.
+ */
+ mtd = &nand_info[devnum];
+
+ /* chip is struct nand_chip, and is now provided by the driver. */
+ mtd->priv = &chip;
+
+ /*
+ * Fill in appropriate values if this driver uses these fields,
+ * or uses the standard read_byte/write_buf/etc. functions from
+ * nand_base.c that use these fields.
+ */
+ chip.IO_ADDR_R = ...;
+ chip.IO_ADDR_W = ...;
+
+ if (nand_scan_ident(mtd, CONFIG_SYS_MAX_NAND_CHIPS, NULL))
+ error out
+
+ /*
+ * Insert here any code you wish to run after the chip has been
+ * identified, but before any other I/O is done.
+ */
+
+ if (nand_scan_tail(mtd))
+ error out
+
+ if (nand_register(devnum))
+ error out
+
+ In addition to providing more flexibility to the driver, it reduces
+ the difference between a U-Boot driver and its Linux counterpart.
+ nand_init() is now reduced to calling board_nand_init() once, and
+ printing a size summary. This should also make it easier to
+ transition to delayed NAND initialization.
+
+ Please convert your driver even if you don't need the extra
+ flexibility, so that one day we can eliminate the old mechanism.
+
NOTE:
=====
"nand unlock [offset] [size]"
unlock consecutive area (can be called multiple times for different areas)
+ "nand unlock.allexcept [offset] [size]"
+ unlock all except specified consecutive area
I have tested the code with board containing 128MiB NAND large page chips
and 32MiB small page chips.
projects / u-boot / blobdiff