The GPMC is a unified memory controller dedicated for interfacing
with external memory devices like
- Asynchronous SRAM-like memories and ASICs
- Asynchronous, synchronous, and page mode burst NOR flash
- NAND flash
- Pseudo-SRAM devices
This driver will take care of setting up the GPMC based on
the settings specified in the Device tree and then
probe its children.
Signed-off-by: Roger Quadros <rogerq@kernel.org>
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from. So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry. Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.
In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.
This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents. There's also a few places where I found we did not have a tag
and have introduced one.
Signed-off-by: Tom Rini <trini@konsulko.com>
Enable GPMC's prefetch feature for NAND access. This speeds up NAND read
access a lot by pre-fetching contents in the background and reading them
through the FIFO address.
The current implementation has two limitations:
a) it only works in 8-bit mode
b) it only supports read access
Both is easily fixable by someone who has hardware to implement it.
Note that U-Boot code uses non word-aligned buffers to read data into, and
request read lengths that are not multiples of 4, so both partial buffers
(head and tail) have to be addressed.
Tested on AM335x hardware.
Tested-by: Guido Martínez <guido@vanguardiasur.com.ar>
Reviewed-by: Guido Martínez <guido@vanguardiasur.com.ar>
Signed-off-by: Daniel Mack <zonque@gmail.com>
[trini: Make apply again, use 'cs' fix pointed out by Guido]
Signed-off-by: Tom Rini <trini@ti.com>
This patch add support for BCH16_ECC to omap_gpmc driver.
*need to BCH16 ECC scheme*
With newer SLC Flash technologies and MLC NAND, and large densities, pagesizes
Flash devices have become more suspectible to bit-flips. Thus stronger
ECC schemes are required for protecting the data.
But stronger ECC schemes have come with larger-sized ECC syndromes which require
more space in OOB/Spare. This puts constrains like;
(a) BCH16_ECC can correct 16 bit-flips per 512Bytes of data.
(b) BCH16_ECC generates 26-bytes of ECC syndrome / 512B.
Due to (b) this scheme can only be used with NAND devices which have enough
OOB to satisfy following equation:
OOBsize per page >= 26 * (page-size / 512)
Signed-off-by: Pekon Gupta <pekon@ti.com>
omap_gpmc.h is a generic header used by OMAP NAND driver for all TI platfoms.
Hence this file should be present in generic folder instead of architecture
specific include folder.
Build tested using: ./MAKEALL -s am33xx -s omap3 -s omap4 -s omap5
Signed-off-by: Pekon Gupta <pekon@ti.com>
2014-03-04 17:23:54 -06:00
Renamed from arch/arm/include/asm/omap_gpmc.h (Browse further)
