[PATCH v4 0/2] Add rockchip serial flash controller support

[Shawn Lin]

Here is another try for adding serial flash controller
, namely SFC, found on Rockchip RK1108 platform.

Feature:
(1) Support x1, x2, x4 data bits mode
(2) Support up to 4 chip select
(3) Support two independent clock domain: AHB clock and SPI clock
(4) Support DMA master up to 16KB/transfer

Test environment:
This patchset was tested on RK1108 evb boards with Winboud flash
(w25q256) and working fine with PIO or DMA mode.

How-to:
Any rockchip guys who are interested in testing it could refer to
the following steps:
(1) enable CONFIG_MTD_M25P80
(2) enable CONFIG_SPI_ROCKCHIP_SFC
(3) enable CONFIG_MTD_CMDLINE_PARTS
(4) enable CONFIG_SQUASHFS
(4) CONFIG_CMDLINE="root=/dev/mtdblock2
	mtdparts=spi-nor:256k at 0(loader)ro,8m(kernel)ro,7m(rootfs),-(freedisk)"
	Of course, you should check the partition layout if you modify it. Also
	you could pass it from your loader to the kernel's cmdline.
(5) Add dts support:
nor_flash: sfc at 301c0000 {
	compatible = "rockchip,rk1108-sfc", "rockchip,sfc";
	#address-cells = <1>;
	#size-cells = <0>;
	clocks = <&cru SCLK_SFC>, <&cru HCLK_SFC>;
	clock-names = "sfc", "hsfc";
	interrupts = <GIC_SPI 56 IRQ_TYPE_LEVEL_HIGH>;
	reg = <0x301c0000 0x1000>;
	/* If you want to use PIO mode, activate this */
	#rockchip,sfc-no-dma;
	spi-nor at 0 {
		compatible = "jedec,spi-nor";
		spi-max-frequency = <12000000>;
		reg = <0>;
	}
};

please make sure your DT's mdtid matchs what you assgin to the
mdtparts(cmdline), namely they are both *spi-nor* here.

With enabling DBG for cmdlinepart.c, you could get following log and
boot kernel and rootfs successfully.

[    0.481420] rockchip-sfc 301c0000.sfc: w25q256 (32768 Kbytes)
[    0.481962] DEBUG-CMDLINE-PART: parsing
<256k at 0(loader)ro,8m(kernel)ro,7m(rootfs)ro,-(freedisk)>
[    0.482897] DEBUG-CMDLINE-PART: partition 3: name
<freedisk>, offset ffffffffffffffff, size ffffffffffffffff, mask flags 0
[    0.484021] DEBUG-CMDLINE-PART: partition 2: name
<rootfs>, offset ffffffffffffffff, size 700000, mask flags 400
[    0.485066] DEBUG-CMDLINE-PART: partition 1: name
<kernel>, offset ffffffffffffffff, size 800000, mask flags 400
[    0.486108] DEBUG-CMDLINE-PART: partition 0: name
<loader>, offset 0, size 40000, mask flags 400
[    0.487152] DEBUG-CMDLINE-PART: mtdid=<spi-nor> num_parts=<4>
[    0.487827] 4 cmdlinepart partitions found on MTD device spi-nor
[    0.488370] Creating 4 MTD partitions on "spi-nor":
[    0.488826] 0x000000000000-0x000000040000 : "loader"
[    0.492340] 0x000000040000-0x000000840000 : "kernel"
[    0.495679] 0x000000840000-0x000000f40000 : "rootfs"
[    0.499241] 0x000000f40000-0x000002000000 : "freedisk"

[root at arm-linux]#
[root at arm-linux]#mount
/dev/root on / type squashfs (ro,relatime)
devtmpfs on /dev type devtmpfs
(rw,relatime,size=26124k,nr_inodes=6531,mode=755)
proc on /proc type proc (rw,relatime)
none on /tmp type ramfs (rw,relatime)
none on /var type ramfs (rw,relatime)
sysfs on /sys type sysfs (rw,relatime)
debug on /sys/kernel/debug type debugfs (rw,relatime)
none on /dev/pts type devpts (rw,relatime,mode=600,ptmxmode=000)


Changes in v4:
- use uppercase DMA for description
- simplify the code of get_if_type
- use dma_dir to simplify the code
- simplify the rockchip_sfc_do_rd_wr
- some minor improvements
- add reset controller when doing resume

Changes in v3:
- use io{read32,write32}_rep to simplify the corner cases
- remove more unnecessary bit definitions
- some minor comment fixes and improvement
- fix wrong unregister function
- unify more code
- use nor to avoid constantly replicating the whole
  sfc->flash[sfc->num_chip].nor
- add email for MODULE_AUTHOR
- remove #if 1 --- #endif
- extract DMA code to imporve the code structure
- reset all when failing to do dma
- pass sfc to get_if_type
- rename sfc-no-dma to sfc-no-DMA

Changes in v2:
- fix typos
- add some comment for buffer and others operations
- rename SFC_MAX_CHIP_NUM to MAX_CHIPSELECT_NUM
- use u8 for cs
- return -EINVAL for default case of get_if_type
- use readl_poll_*() to check timeout cases
- simplify and clarify some condition checks
- rework the bitshifts to simplify the code
- define SFC_CMD_DUMMY(x)
- fix ummap for dma read path and finish all the
  cache maintenance.
- rename to rockchip_sfc_chip_priv and embed struct spi_nor
  in it.
- add MODULE_AUTHOR
- add runtime PM and general PM support.
- Thanks for Marek's comments. Link:
  http://lists.infradead.org/pipermail/linux-mtd/2016-November/070321.html

Shawn Lin (2):
  mtd: spi-nor: Bindings for Rockchip serial flash controller
  mtd: spi-nor: add rockchip serial flash controller driver

 .../devicetree/bindings/mtd/rockchip-sfc.txt       |  31 +
 MAINTAINERS                                        |   8 +
 drivers/mtd/spi-nor/Kconfig                        |   7 +
 drivers/mtd/spi-nor/Makefile                       |   1 +
 drivers/mtd/spi-nor/rockchip-sfc.c                 | 872 +++++++++++++++++++++
 5 files changed, 919 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mtd/rockchip-sfc.txt
 create mode 100644 drivers/mtd/spi-nor/rockchip-sfc.c

-- 
1.9.1