This driver's chip support is currently provided as two files:
Prototypes the low-level chip access functions required by the chip driver and declares a private struct for use by the driver.
Implements high-level chip functions and exposes them via the CYG_NAND_FUNS macro. This file is not intended to be compiled on its own.
A platform HAL would typically make use of this driver in a single source file with the following steps:
Declare a private struct and one or more static instances of it as appropriate,
#include <cyg/devs/nand/k9fxx08x0x.h>
implement the required low-level functions,
#include <cyg/devs/nand/k9fxx08x0x.inl>
finally, instantiate the chip with the CYG_NAND_DEVICE macro the appropriate number of times, giving each chip an appropriate name, its own private struct if need be, and selecting the ECC and OOB semantics to use.
For more details about the infrastructure provided by the NAND layer and the semantics it expects of the chip driver, refer to Part VII in eCosPro® Reference Manual. An example driver instantiation can be found in the NAND driver for the EA LPC2468 platform.
As discussed in the Section called High-level (chip) functions in Chapter 8, the chip
initialisation function must set up the bbt.data
pointer in the cyg_nand_device struct. This driver does so
by including a sufficiently large byte array in the k9_priv
struct. That struct is intended to be allocated as a static struct in the
data or BSS segment (one per chip), which avoids adding a dependency
on malloc.
These functions are prototyped in
k9fxx08x0x.h.
They have no return value ("void"), except for
read_data_1 which returns the byte it has read.
write_cmd(device,
command)Writes a single command byte to the chip's command latch.
write_addrbytes(device, pointer to bytes,
number of bytes)Writes a number of address bytes in turn to the chip's address latch.
CYG_BYTE read_data_1(device),
read_data_bulk(device, output pointer, number of
bytes)Reads data from the device, respectively a single byte and in bulk.
write_data_1(device, byte),
write_data_bulk(device, data pointer, number of
bytes)Writes data to the device, respectively a single byte and in bulk.
wait_ready_or_time(device, initial delay,
fallback time)Wait for the chip to signal READY line or, if this line is not available, fall back to a worst-case time delay (measured in microseconds).
wait_ready_or_status(device,
mask)Wait for the chip to signal READY line or, if this line is not available, enter a loop waiting for its Status register (ANDed with the given mask) to be non-zero.
k9_devlock(device),
k9_devunlock(device)Hooks for any board-specific locking which may be required in addition to the NAND library's chip-level locking. (This would be useful if, for example, access to multiple chips was mediated by a single set of GPIO lines which ought not to be invoked concurrently.)
k9_plf_init(device)Board-level platform initialisation hook. This is called very early on in the chip initialisation routine; it should set up any locking required by the devlock and devunlock functions, interrupts for the driver and any further lines required to access the chip as approprate. Once this has returned, the chip driver assumes that the platform is fully prepared for it to call the other chip access functions.
k9_plf_partition_setup(device)Board-level partition initialisation hook. This should set up the partition array of the device struct in a way which is appropriate to the platform. For example, the partitions may be set as fixed ranges of blocks, or by CDL. This is called at the end of the chip initialisation routine and may, for example, call into the chip to read out a "partition table" if one is present on the board. If you do not set up partitions, applications will not be able to use the high-level chip access functions provided the NAND library.