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Date:   Tue, 05 May 2020 16:23:59 -0700 (PDT)
Subject:     RE: [PATCH 1/2] riscv: defconfig: enable spi nor on Hifive Unleashed A00 board.
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CC:     tudor.ambarus@microchip.com, miquel.raynal@bootlin.com,
        richard@nod.at, vigneshr@ti.com,
        Paul Walmsley <paul.walmsley@sifive.com>,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-mtd@lists.infradead.org
From:   Palmer Dabbelt <palmer@dabbelt.com>
To:     sagar.kadam@sifive.com
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On Tue, 05 May 2020 00:18:45 PDT (-0700), sagar.kadam@sifive.com wrote:
> Hello Palmer,
> 
>> -----Original Message-----
>> From: Palmer Dabbelt <palmer@dabbelt.com>
>> Sent: Tuesday, May 5, 2020 3:40 AM
>> To: Sagar Kadam <sagar.kadam@sifive.com>
>> Cc: tudor.ambarus@microchip.com; miquel.raynal@bootlin.com;
>> richard@nod.at; vigneshr@ti.com; Paul Walmsley
>> <paul.walmsley@sifive.com>; linux-riscv@lists.infradead.org; linux-
>> kernel@vger.kernel.org; linux-mtd@lists.infradead.org; Sagar Kadam
>> <sagar.kadam@sifive.com>
>> Subject: Re: [PATCH 1/2] riscv: defconfig: enable spi nor on Hifive Unleashed
>> A00 board.
>> 
>> [External Email] Do not click links or attachments unless you recognize the
>> sender and know the content is safe
>> 
>> On Thu, 30 Apr 2020 02:58:51 PDT (-0700), sagar.kadam@sifive.com wrote:
>> > Enable MTD based SPI-NOR framework in order to use spi flash available
>> > on HiFive Unleashed A00 board.
>> >
>> > Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
>> > ---
>> >  arch/riscv/configs/defconfig | 2 ++
>> >  1 file changed, 2 insertions(+)
>> >
>> > diff --git a/arch/riscv/configs/defconfig
>> > b/arch/riscv/configs/defconfig index 4da4886..970580b 100644
>> > --- a/arch/riscv/configs/defconfig
>> > +++ b/arch/riscv/configs/defconfig
>> > @@ -80,6 +80,8 @@ CONFIG_USB_STORAGE=y  CONFIG_USB_UAS=y
>> CONFIG_MMC=y
>> > CONFIG_MMC_SPI=y
>> > +CONFIG_MTD=y
>> > +CONFIG_MTD_SPI_NOR=y
>> >  CONFIG_RTC_CLASS=y
>> >  CONFIG_VIRTIO_PCI=y
>> >  CONFIG_VIRTIO_BALLOON=y
>> 
>> From the second patch's description I'm assuming that MTD still functions
>> correctly without that change?
> 
> Yes Palmer, the second patch is to enable QUAD write to nor flash..
> MTD  function's correctly without second patch.
>
> Using the character interface (/dev/mtd0) mtd_utils (mtd_debug : erase/read/write) work fine.
> We might require CONFIG_MTD_BLOCK, CONFIG_MTD_CMDLINE_PARTS  in order to use MTD partitioning.
> IMHO it can be at user's choice weather to use flash partitions or not, so I have not enabled. Please let me 
> know if I should enable these features as well.

Looks like arm64 has these:

arch/arm64/configs/defconfig:CONFIG_MTD=y
arch/arm64/configs/defconfig:CONFIG_MTD_BLOCK=y
arch/arm64/configs/defconfig:CONFIG_MTD_CFI=y
arch/arm64/configs/defconfig:CONFIG_MTD_CFI_ADV_OPTIONS=y
arch/arm64/configs/defconfig:CONFIG_MTD_CFI_INTELEXT=y
arch/arm64/configs/defconfig:CONFIG_MTD_CFI_AMDSTD=y
arch/arm64/configs/defconfig:CONFIG_MTD_CFI_STAA=y
arch/arm64/configs/defconfig:CONFIG_MTD_PHYSMAP=y
arch/arm64/configs/defconfig:CONFIG_MTD_PHYSMAP_OF=y
arch/arm64/configs/defconfig:CONFIG_MTD_DATAFLASH=y
arch/arm64/configs/defconfig:CONFIG_MTD_SST25L=y
arch/arm64/configs/defconfig:CONFIG_MTD_RAW_NAND=y
arch/arm64/configs/defconfig:CONFIG_MTD_NAND_DENALI_DT=y
arch/arm64/configs/defconfig:CONFIG_MTD_NAND_MARVELL=y
arch/arm64/configs/defconfig:CONFIG_MTD_NAND_FSL_IFC=y
arch/arm64/configs/defconfig:CONFIG_MTD_NAND_QCOM=y
arch/arm64/configs/defconfig:CONFIG_MTD_SPI_NOR=y

so I think we're good with just what you have here: MTD_BLOCK doesn't seem that
useful, and the rest are drivers.  That said, these (along with SPI and
SPI_SIFIVE) should really be in Kconfig.socs rather than defconfig.  Can you
send a patch that does that?

> 
> To demonstrate a bit more with linux 5.7-rc3 
> 
> Specify on U-boot prompt:
> # setenv bootargs "root=/dev/ram rw console=ttySIF0 mtdparts=spi0.0:1024k(loader1),4096K(loader2),26M(rootfs)"
> 
> After booting linux will enumerate mtd partitions:
> # cat /proc/mtd
> dev:    size   erasesize  name
> mtd0: 00100000 00001000 "loader1"
> mtd1: 00400000 00001000 "loader2"
> mtd2: 01a00000 00001000 "rootfs"
> 
> # cat /proc/partitions
> major minor  #blocks  name
>   31        0       1024 mtdblock0
>   31        1       4096 mtdblock1
>   31        2      26624 mtdblock2
> 
> #Format mtdblock2 with mkfs.ext3/4 and mount results in
> # mkfs.ext3 /dev/mtdblock2
> mke2fs 1.44.5 (15-Dec-2018)
> /dev/mtdblock2 contains a ext3 file system
>         last mounted on /mnt on Thu Jan  1 00:00:14 1970
> Proceed anyway? (y,N) y
> Creating filesystem with 26624 1k blocks and 6656 inodes
> Filesystem UUID: 1b09252d-e313-430c-9ecb-79b0cef003ca
> Superblock backups stored on blocks:
>         8193, 24577
> 
> Allocating group tables: done
> Writing inode tables: done
> Creating journal (1024 blocks): done
> Writing superblocks and filesystem accounting information: done
> 
> # mount
> none on / type rootfs (rw)
> proc on /proc type proc (rw,relatime)
> devpts on /dev/pts type devpts (rw,relatime,gid=5,mode=620,ptmxmode=666)
> tmpfs on /dev/shm type tmpfs (rw,relatime,mode=777)
> tmpfs on /tmp type tmpfs (rw,relatime)
> tmpfs on /run type tmpfs (rw,nosuid,nodev,relatime,mode=755)
> sysfs on /sys type sysfs (rw,relatime)
> /dev/mtdblock2 on /mnt type ext3 (rw,relatime)
> 
> Thanks & BR,
> Sagar Kadam