mtd: atmel_nand: add Nand Flash Controller (NFC) support

Nand Flash Controller (NFC) can handle automatic transfers, sending the
commands and address cycles to the NAND Flash.

To use NFC in this driver, user needs to add NFC child node in nand flash
driver. The NFC child node includes NFC's compatible string and regiters
of the address and size of NFC command registers, NFC registers (embedded
in HSMC) and NFC SRAM.
Also user need to set up the HSMC irq, which use to check whether nfc
command is finish or not.

This driver has been tested on SAMA5D3X-EK board with JFFS2, YAFFS,
UBIFS and mtd-utils.

I put the part of the mtd_speedtest result here for your information.
>From the mtd_speedtest, we can see the NFC will reduce the %50 of cpu load
when writing nand flash. No change when reading.
In the meantime, the speed will be slow about %8.

- commands use to test:
    #insmod /mnt/mtd_speedtest.ko dev=2 &
    #top -n 30 -d 1 | grep speedtest

- test result:

Before the patch:
=================================================
mtd_speedtest: MTD device: 2
mtd_speedtest: MTD device size 41943040, eraseblock size 131072, page size 2048, count of eraseblocks 320, pages per eraseblock 64, OOB size 64
  515   495 root     R     1164   0%  93% insmod /mnt/mtd_speedtest.ko dev=2
  515   495 root     R     1164   0%  98% insmod /mnt/mtd_speedtest.ko dev=2
  515   495 root     R     1164   0%  99% insmod /mnt/mtd_speedtest.ko dev=2
mtd_speedtest: eraseblock write speed is 5768 KiB/s
mtd_speedtest: testing eraseblock read speed
  515   495 root     R     1164   0%  92% insmod /mnt/mtd_speedtest.ko dev=2
  515   495 root     R     1164   0%  91% insmod /mnt/mtd_speedtest.ko dev=2
  515   495 root     R     1164   0%  94% insmod /mnt/mtd_speedtest.ko dev=2
mtd_speedtest: eraseblock read speed is 5932 KiB/s
mtd_speedtest: testing page write speed
  515   495 root     R     1164   0%  94% insmod /mnt/mtd_speedtest.ko dev=2
  515   495 root     R     1164   0%  98% insmod /mnt/mtd_speedtest.ko dev=2
  515   495 root     R     1164   0%  98% insmod /mnt/mtd_speedtest.ko dev=2
mtd_speedtest: page write speed is 5770 KiB/s
mtd_speedtest: testing page read speed
  515   495 root     R     1164   0%  91% insmod /mnt/mtd_speedtest.ko dev=2
  515   495 root     R     1164   0%  89% insmod /mnt/mtd_speedtest.ko dev=2
  515   495 root     R     1164   0%  91% insmod /mnt/mtd_speedtest.ko dev=2
mtd_speedtest: page read speed is 5910 KiB/s

After the patch:
=================================================
mtd_speedtest: MTD device: 2
mtd_speedtest: MTD device size 41943040, eraseblock size 131072, page size 2048, count of eraseblocks 320, pages per eraseblock 64, OOB size 64
mtd_speedtest: testing eraseblock write speed
  509   495 root     D     1164   0%  49% insmod /mnt/mtd_speedtest.ko dev=2
  509   495 root     D     1164   0%  50% insmod /mnt/mtd_speedtest.ko dev=2
  509   495 root     D     1164   0%  47% insmod /mnt/mtd_speedtest.ko dev=2
mtd_speedtest: eraseblock write speed is 5370 KiB/s
mtd_speedtest: testing eraseblock read speed
  509   495 root     R     1164   0%  92% insmod /mnt/mtd_speedtest.ko dev=2
  509   495 root     R     1164   0%  91% insmod /mnt/mtd_speedtest.ko dev=2
  509   495 root     R     1164   0%  95% insmod /mnt/mtd_speedtest.ko dev=2
mtd_speedtest: eraseblock read speed is 5715 KiB/s
mtd_speedtest: testing page write speed
  509   495 root     D     1164   0%  48% insmod /mnt/mtd_speedtest.ko dev=2
  509   495 root     D     1164   0%  47% insmod /mnt/mtd_speedtest.ko dev=2
  509   495 root     D     1164   0%  50% insmod /mnt/mtd_speedtest.ko dev=2
mtd_speedtest: page write speed is 5224 KiB/s
mtd_speedtest: testing page read speed
  509   495 root     R     1164   0%  89% insmod /mnt/mtd_speedtest.ko dev=2
  509   495 root     R     1164   0%  94% insmod /mnt/mtd_speedtest.ko dev=2
  509   495 root     R     1164   0%  93% insmod /mnt/mtd_speedtest.ko dev=2
mtd_speedtest: page read speed is 5641 KiB/s

Signed-off-by: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/mtd/atmel-nand.txt b/Documentation/devicetree/bindings/mtd/atmel-nand.txt
index b6eb484366a5..5d8b7d5c914d 100644
--- a/Documentation/devicetree/bindings/mtd/atmel-nand.txt
+++ b/Documentation/devicetree/bindings/mtd/atmel-nand.txt
@@ -30,6 +30,12 @@ Optional properties:
   sector size 1024.
 - nand-bus-width : 8 or 16 bus width if not present 8
 - nand-on-flash-bbt: boolean to enable on flash bbt option if not present false
+- Nand Flash Controller(NFC) is a slave driver under Atmel nand flash
+  - Required properties:
+    - compatible : "atmel,sama5d3-nfc".
+    - reg : should specify the address and size used for NFC command registers,
+            NFC registers and NFC Sram. NFC Sram address and size can be absent
+            if don't want to use it.
 
 Examples:
 nand0: nand@40000000,0 {
@@ -78,3 +84,22 @@ nand0: nand@40000000 {
 		...
 	};
 };
+
+/* for NFC supported chips */
+nand0: nand@40000000 {
+	compatible = "atmel,at91rm9200-nand";
+	#address-cells = <1>;
+	#size-cells = <1>;
+	ranges;
+        ...
+        nfc@70000000 {
+		compatible = "atmel,sama5d3-nfc";
+		#address-cells = <1>;
+		#size-cells = <1>;
+		reg = <
+			0x70000000 0x10000000	/* NFC Command Registers */
+			0xffffc000 0x00000070	/* NFC HSMC regs */
+			0x00200000 0x00100000	/* NFC SRAM banks */
+		>;
+	};
+};