mtd: nand: pxa3xx: Add driver-specific ECC BCH support

This commit adds the BCH ECC support available in NFCv2 controller.
Depending on the detected required strength the respective ECC layout
is selected.

This commit adds an empty ECC layout, since support to access large
pages is first required. Once that support is added, a proper ECC
layout will be added as well.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
mtd: nand: pxa3xx: Clear cmd buffer #3 (NDCB3) on command start

Command buffer #3 is not properly cleared and it keeps the last
set value. Fix this by clearing when a command is setup.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
mtd: nand: pxa3xx: Add helper function to set page address

Let's simplify the code by first introducing a helper function
to set the page address, as done by the READ0, READOOB and SEQIN
commands.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
mtd: nand: pxa3xx: Remove READ0 switch/case falltrough

READ0 and READOOB command preparation has a falltrough to SEQIN
case, where the command address is specified.
This is certainly confusing and makes the code less readable with
no added value. Let's remove it.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
mtd: nand: pxa3xx: Split prepare_command_pool() in two stages

This commit splits the prepare_command_pool() function into two
stages: prepare_start_command() / prepare_set_command().

This is a preparation patch without any functionality changes,
and is meant to allow support fir multiple page reading/writing
operations.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
mtd: nand: pxa3xx: Move the data buffer clean to prepare_start_command()

To allow future support of multiple page reading/writing, move the data
buffer clean out of prepare_set_command().

This is done to prevent the data buffer from being cleaned on every command
preparation, when a multiple command sequence is implemented to read/write
pages larger than the FIFO size (2 KiB).

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
mtd: nand: pxa3xx: Fix SEQIN column address set

This commit adds support page programming with a non-zero "column"
address setting. This is important to support OOB writing, through
command sequences such as:

  cmdfunc(mtd, NAND_CMD_SEQIN, mtd->writesize, ofs);
  write_buf(mtd, oob_buf, 6);
  cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1);

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
mtd: nand: pxa3xx: Add a read/write buffers markers

In preparation to support multiple (aka chunked, aka splitted)
page I/O, this commit adds 'data_buff_pos' and 'oob_buff_pos' fields
to keep track of where the next read (or write) should be done.

This will allow multiple calls to handle_data_pio() to continue
the read (or write) operation.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
mtd: nand: pxa3xx: Introduce multiple page I/O support

As preparation work to fully support large pages, this commit adds
the initial infrastructure to support splitted (aka chunked) I/O
operation. This commit adds support for read, and follow-up patches
will add write support.

When a read (aka READ0) command is issued, the driver loops issuing
the same command until all the requested data is transfered, changing
the 'extended' command field as needed.

For instance, if the driver is required to read a 4 KiB page, using a
chunk size of 2 KiB, the transaction is splitted in:
1. Monolithic read, first 2 KiB page chunk is read
2. Last naked read, second and last 2KiB page chunk is read

If ECC is enabled it is calculated on each chunk transfered and added
at a controller-fixed location after the data chunk that must be
spare area.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
mtd: nand: pxa3xx: Add multiple chunk write support

This commit adds write support for large pages (4 KiB, 8 KiB).
Such support is implemented by issuing a multiple command sequence,
transfering a set of 2 KiB chunks per transaction.

The splitted command sequence requires to send the SEQIN command
independently of the PAGEPROG command and therefore it's set as
an execution command.

Since PAGEPROG enables ECC, each 2 KiB chunk of data is written
together with ECC code at a controller-fixed location within
the flash page.

Currently, only devices with a 4 KiB page size has been tested.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
mtd: nand: pxa3xx: Add ECC BCH correctable errors detection

This commit extends the ECC correctable error detection to include
ECC BCH errors. The number of BCH correctable errors can be any up to 16,
and the actual value is exposed in the NDSR register.

Therefore, we change some symbol names to refer to correctable or
uncorrectable (instead of single-bit or double-bit as it was in the
Hamming case) and while at it, cleanup the detection code slightly.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
ARM: mvebu: Add support for NAND controller in Armada 370/XP

The Armada 370 and Armada XP SoC have a NAND controller (aka NFCv2).
This commit adds support for it in Armada 370 and Armada XP SoC
common devicetree.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
ARM: mvebu: Enable NAND controller in Armada XP GP board

The Armada XP GP board has a NAND flash, so enable it in the devicetree.

In order to skip the driver's custom device detection and use only ONFI
detection, the "marvell,keep-config" parameter is used.
This is needed because we haven't support for setting the timings
parameters yet and must rely in bootloader's.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
ARM: mvebu: Enable NAND controller in Armada 370 Mirabox

The Armada 370 Mirabox has a NAND flash, so enable it in the devicetree
and add the partitions as prepared in the factory images.

In order to skip the driver's custom device detection and use only
ONFI detection, the "marvell,keep-config" parameter is used.
This is needed because we have no support for setting the timings parameters yet.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>