Jaime Liao/TAIWAN/MXIC 已在 2021/06/21 上午 09:59:29 上寫入:
> JaimeLiao 廖俊明/台灣/旺宏
> 2021/06/21 上午 09:59
>
> 收件人
>
> "Pratyush Yadav" <p.ya...@ti.com>,
>
> 副本抄送
>
> chris.pack...@alliedtelesis.co.nz, chunfeng....@mediatek.com,
> gss_mtk_uboot_upstr...@mediatek.com, ja...@amarulasolutions.com,
> ryder....@mediatek.com, u-boot@lists.denx.de, vigne...@ti.com,
> weijie....@mediatek.com, zhengxu...@mxic.com.tw
>
> 主旨
>
> 回信: Re: [v9,23/28] mtd: spi-nor-core: Perform a Soft Reset on shutdown
>
> Hi Pratyush
>
> > Hi,
> >
> > On 18/06/21 04:55PM, jaimel...@mxic.com.tw wrote:
> > >
> > > Hi Pratyush
> > >
> > >
> > > +#ifdef CONFIG_SPI_FLASH_SOFT_RESET
> > > +/**
> > > + * spi_nor_soft_reset() - perform the JEDEC Software Reset sequence
> > > + * @nor: the spi_nor structure
> > > + *
> > > + * This function can be used to switch from Octal DTR mode to
> legacy mode
> > > on a
> > > + * flash that supports it. The soft reset is executed in Octal DTR
mode.
> > > + *
> > > + * Return: 0 for success, -errno for failure.
> > > + */
> > > +static int spi_nor_soft_reset(struct spi_nor *nor)
> > > +{
> > > + struct spi_mem_op op;
> > > + int ret;
> > > + enum spi_nor_cmd_ext ext;
> > > +
> > > + ext = nor->cmd_ext_type;
> > > + nor->cmd_ext_type = SPI_NOR_EXT_REPEAT;
> > > According JEDEC, cmd_ext_type has two different types, REPEAT and
INVERT.
> > > Some Flash vendor using "INVERT" as cmd_ext_type so that it is not
> > > suitable for hard coding the type as REPEAT.
> > > Sending twice reset command with different types is clumsy but
useful
> > > before read ID for getting Flash information.
> > > It would be great if you have any other ideas for this part.
> >
> > It is possible to discover the extension type from BFPT (if the flash
> > supports it, that is). But this function is supposed to be called
before
> > anything else to make sure the flash is in a sane state. For that
> > reason, I don't think SFDP would be a viable approach.
> >
> > Executing it twice might be a viable option. We need to see how flash
> > that expect invert react to a repeat opcode, and vice versa.
For this part, we got a conclusion on Macronix Flash after testing.
Macronix Flash will not reply anything if react to a repeat opcode in
octal dtr mode.
> >
> > Anyway, I don't think this is a problem for now. Both the 8D-8D-8D
> > capable flashes supported with this series expect a repeat opcode.
> According Macronix SPI-NOR octal bus Flash datasheet.
> https://www.mxic.com.tw/Lists/Datasheet/Attachments/7721/
> MX66UM1G45G,%201.8V,%201Gb,%20v1.1.pdf
> Most of SPI-NOR octal bus Flash are all need invert extension opcode
> in octal dtr mode.
> I think repeat and invert opcode are necessary for different vendor
Flash.
> >
> > >
> > > +
> > > + op = (struct
> > > spi_mem_op)SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_SRSTEN, 0),
> > > + SPI_MEM_OP_NO_DUMMY,
> > > + SPI_MEM_OP_NO_ADDR,
> > > + SPI_MEM_OP_NO_DATA);
> > > + spi_nor_setup_op(nor, &op, SNOR_PROTO_8_8_8_DTR);
> > > + ret = spi_mem_exec_op(nor->spi, &op);
> > > + if (ret) {
> > > + dev_warn(nor->dev, "Software
> reset enable
> > > failed: %d\n", ret);
> > > + goto out;
> > > + }
> > > +
> > > + op = (struct
> > > spi_mem_op)SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_SRST, 0),
> > > + SPI_MEM_OP_NO_DUMMY,
> > > + SPI_MEM_OP_NO_ADDR,
> > > + SPI_MEM_OP_NO_DATA);
> > > + spi_nor_setup_op(nor, &op, SNOR_PROTO_8_8_8_DTR);
> > > + ret = spi_mem_exec_op(nor->spi, &op);
> > > + if (ret) {
> > > + dev_warn(nor->dev, "Software reset
> > > failed: %d\n", ret);
> > > + goto out;
> > > + }
> > > +
> > > + /*
> > > + * Software Reset is not instant, and the delay
varies
> > > from flash to
> > > + * flash. Looking at a few flashes, most range
somewhere
> > > below 100
> > > + * microseconds. So, wait for 200ms just to be
sure.
> > > + */
> > > + udelay(SPI_NOR_SRST_SLEEP_LEN);
> > > +
> > > +out:
> > > + nor->cmd_ext_type = ext;
> > > + return ret;
> > > +}
> > >
> > >
> > > Thanks
> > > Jaime
> >
> > --
> > Regards,
> > Pratyush Yadav
> > Texas Instruments Inc.
>
> Thanks
> Jaime
>
Thanks
Jaime
CONFIDENTIALITY NOTE:
This e-mail and any attachments may contain confidential information
and/or personal data, which is protected by applicable laws. Please be
reminded that duplication, disclosure, distribution, or use of this e-mail
(and/or its attachments) or any part thereof is prohibited. If you receive
this e-mail in error, please notify us immediately and delete this mail as
well as its attachment(s) from your system. In addition, please be
informed that collection, processing, and/or use of personal data is
prohibited unless expressly permitted by personal data protection laws.
Thank you for your attention and cooperation.
Macronix International Co., Ltd.
=====================================================================
============================================================================
CONFIDENTIALITY NOTE:
This e-mail and any attachments may contain confidential information and/or
personal data, which is protected by applicable laws. Please be reminded that
duplication, disclosure, distribution, or use of this e-mail (and/or its
attachments) or any part thereof is prohibited. If you receive this e-mail in
error, please notify us immediately and delete this mail as well as its
attachment(s) from your system. In addition, please be informed that
collection, processing, and/or use of personal data is prohibited unless
expressly permitted by personal data protection laws. Thank you for your
attention and cooperation.
Macronix International Co., Ltd.
=====================================================================
