From: Pratyush Yadav <p.yadav@ti.com>
To: <Tudor.Ambarus@microchip.com>
Cc: alexandre.belloni@bootlin.com, vigneshr@ti.com, richard@nod.at,
broonie@kernel.org, nsekhar@ti.com, linux-kernel@vger.kernel.org,
Nicolas.Ferre@microchip.com, Ludovic.Desroches@microchip.com,
boris.brezillon@collabora.com, linux-mtd@lists.infradead.org,
miquel.raynal@bootlin.com, linux-spi@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v4 00/16] mtd: spi-nor: add xSPI Octal DTR support
Date: Wed, 13 May 2020 00:16:58 +0530 [thread overview]
Message-ID: <20200512184656.ksudjyeqbwv6jze6@ti.com> (raw)
In-Reply-To: <2352513.UHBGRE98Z5@192.168.0.120>
On 12/05/20 11:29AM, Tudor.Ambarus@microchip.com wrote:
> Hi, Vignesh,
>
> > > The software reset procedure can't protect you from unexpected
> > > resets, but
> > > the hardware with its optional reset pin can. Pratyush to confirm.
> > >
> > > cut
> > >
> > >>> Not recovering from unexpected resets is unacceptable. One should always
> > >>> prefer option 1/ and condition the entering in 2-2-2, 4-4-4 and 8-8-8
> > >>> with
> > >>> the presence of the optional RESET pin.
> > >>
> > >> Totally agree with you on that one, but we know what happens in
> > >> practice...
> > >
> > > What I proposed is to condition the entering in the state-full modes with
> > > the presence of the optional RESET pin. We would introduce an optional
> > > device tree property for the RESET pin. If hardware doesn't implement the
> > > optional RESET# signal, then we will not enter in the state-full modes.
> >
> > Are you asking for dedicated SW controllable reset line or just an
> > indication from DT that OSPI reset line is connected to board level
> > soft/hard reset lines?
>
> I don't see a need for the reset line to be SW controllable, a simple
> indication from the device tree should be enough.
We already have the property "broken-flash-reset". Should we re-use it
or should we have a opt-in property instead of an opt-out one?
> >
> > Mandating SW controllable RESET line is bit of a stretch IMO... Board
> > design may not allow wasting dedicated pin due to lack of GPIOs perhaps..
> >
> > For eg.: TI EVM has OSPI reset line connected to board level reset out.
> > This ensures any soft/warm/hard CPU reset will trigger OSPI Flash reset,
> > but there is no SW control that allows OSPI flash alone to be reset.
> > Isn't such a reset mechanism sufficient?
> >
>
> I think it is, yes.
--
Regards,
Pratyush Yadav
Texas Instruments India
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next prev parent reply other threads:[~2020-05-12 18:47 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-24 18:43 [PATCH v4 00/16] mtd: spi-nor: add xSPI Octal DTR support Pratyush Yadav
2020-04-24 18:43 ` [PATCH v4 01/16] spi: spi-mem: allow specifying whether an op is DTR or not Pratyush Yadav
2020-04-24 18:43 ` [PATCH v4 02/16] spi: atmel-quadspi: reject DTR ops Pratyush Yadav
2020-04-30 11:32 ` Mark Brown
2020-04-30 12:17 ` Pratyush Yadav
2020-04-30 12:19 ` Mark Brown
2020-04-24 18:43 ` [PATCH v4 03/16] spi: spi-mem: allow specifying a command's extension Pratyush Yadav
2020-04-24 18:43 ` [PATCH v4 04/16] mtd: spi-nor: add support for DTR protocol Pratyush Yadav
2020-04-24 18:43 ` [PATCH v4 05/16] mtd: spi-nor: default to address width of 3 for configurable widths Pratyush Yadav
2020-04-26 3:53 ` Yicong Yang
2020-04-27 17:23 ` Pratyush Yadav
2020-04-28 1:34 ` Yicong Yang
2020-04-28 5:25 ` Tudor.Ambarus
2020-04-24 18:44 ` [PATCH v4 06/16] mtd: spi-nor: prepare BFPT parsing for JESD216 rev D Pratyush Yadav
2020-04-24 18:44 ` [PATCH v4 07/16] mtd: spi-nor: get command opcode extension type from BFPT Pratyush Yadav
2020-04-24 18:44 ` [PATCH v4 08/16] mtd: spi-nor: parse xSPI Profile 1.0 table Pratyush Yadav
2020-04-24 18:44 ` [PATCH v4 09/16] mtd: spi-nor: use dummy cycle and address width info from SFDP Pratyush Yadav
2020-04-24 18:44 ` [PATCH v4 10/16] mtd: spi-nor: do 2 byte reads for SR and FSR in DTR mode Pratyush Yadav
2020-04-24 18:44 ` [PATCH v4 11/16] mtd: spi-nor: enable octal DTR mode when possible Pratyush Yadav
2020-04-24 18:44 ` [PATCH v4 12/16] mtd: spi-nor: perform a Soft Reset on shutdown Pratyush Yadav
2020-05-10 11:22 ` Tudor.Ambarus
2020-05-11 18:01 ` Pratyush Yadav
2020-04-24 18:44 ` [PATCH v4 13/16] mtd: spi-nor: Disable Octal DTR mode on suspend Pratyush Yadav
2020-04-24 18:44 ` [PATCH v4 14/16] mtd: spi-nor: expose spi_nor_default_setup() in core.h Pratyush Yadav
2020-04-24 18:44 ` [PATCH v4 15/16] mtd: spi-nor: add support for Cypress Semper flash Pratyush Yadav
2020-04-24 18:44 ` [PATCH v4 16/16] mtd: spi-nor: allow using MT35XU512ABA in Octal DTR mode Pratyush Yadav
2020-05-11 9:00 ` [PATCH v4 00/16] mtd: spi-nor: add xSPI Octal DTR support Tudor.Ambarus
2020-05-11 9:27 ` Boris Brezillon
2020-05-11 18:24 ` Pratyush Yadav
2020-05-12 6:16 ` Tudor.Ambarus
2020-05-12 9:49 ` Vignesh Raghavendra
2020-05-12 11:29 ` Tudor.Ambarus
2020-05-12 18:46 ` Pratyush Yadav [this message]
2020-05-11 9:43 ` Vignesh Raghavendra
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