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From: Michael Walle <michael@walle.cc>
To: Pratyush Yadav <p.yadav@ti.com>
Cc: Tudor Ambarus <tudor.ambarus@microchip.com>,
	miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com,
	linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org,
	nicolas.ferre@microchip.com
Subject: Re: [PATCH v2 4/8] mtd: spi-nor: core: Introduce method for RDID op
Date: Tue, 22 Mar 2022 09:19:49 +0100	[thread overview]
Message-ID: <eca7100c7e6dacd9cb9e18b5bee3e2ab@walle.cc> (raw)
In-Reply-To: <20220322073209.26m2udmftiaxxtcq@ti.com>

Am 2022-03-22 08:32, schrieb Pratyush Yadav:
> On 21/03/22 11:56PM, Michael Walle wrote:
>> Am 2022-02-28 12:17, schrieb Tudor Ambarus:
>> > RDID is used in the core to auto detect the flash, but also by some
>> > manufacturer drivers that contain flashes that support Octal DTR mode,
>> > so that they can read the flash ID after the switch to Octal DTR was
>> > made
>> > to test if the switch was successful. Introduce a core method for RDID
>> > op
>> > to avoid code duplication.
>> 
>> Some or all? Is that specific to the flash or can we just check that
>> readid works in spi_nor_octal_dtr_enable()? That way we could also
>> just get rid of the proto parameter for the read_id because it can
>> be called after we set the reg_proto.
> 
> It is specific to the flash. Not all flashes support RDID in 8D mode.
> And the RDID command is also different in 8D mode for various flashes.
> For example, Micron MT35XU512ABA flash expects 8 dummy cycles and 0
> address cycles. Cypress S28HS512T expects 4 address cycles and 3 dummy
> cycles.
> 
> The octal_dtr_enable hook would know what parameters to use but it is
> harder for the core to know since this information is not discoverable
> via SFDP.

Ah, I see, thanks for clarification.

-michael

WARNING: multiple messages have this Message-ID (diff)
From: Michael Walle <michael@walle.cc>
To: Pratyush Yadav <p.yadav@ti.com>
Cc: Tudor Ambarus <tudor.ambarus@microchip.com>,
	miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com,
	linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org,
	nicolas.ferre@microchip.com
Subject: Re: [PATCH v2 4/8] mtd: spi-nor: core: Introduce method for RDID op
Date: Tue, 22 Mar 2022 09:19:49 +0100	[thread overview]
Message-ID: <eca7100c7e6dacd9cb9e18b5bee3e2ab@walle.cc> (raw)
In-Reply-To: <20220322073209.26m2udmftiaxxtcq@ti.com>

Am 2022-03-22 08:32, schrieb Pratyush Yadav:
> On 21/03/22 11:56PM, Michael Walle wrote:
>> Am 2022-02-28 12:17, schrieb Tudor Ambarus:
>> > RDID is used in the core to auto detect the flash, but also by some
>> > manufacturer drivers that contain flashes that support Octal DTR mode,
>> > so that they can read the flash ID after the switch to Octal DTR was
>> > made
>> > to test if the switch was successful. Introduce a core method for RDID
>> > op
>> > to avoid code duplication.
>> 
>> Some or all? Is that specific to the flash or can we just check that
>> readid works in spi_nor_octal_dtr_enable()? That way we could also
>> just get rid of the proto parameter for the read_id because it can
>> be called after we set the reg_proto.
> 
> It is specific to the flash. Not all flashes support RDID in 8D mode.
> And the RDID command is also different in 8D mode for various flashes.
> For example, Micron MT35XU512ABA flash expects 8 dummy cycles and 0
> address cycles. Cypress S28HS512T expects 4 address cycles and 3 dummy
> cycles.
> 
> The octal_dtr_enable hook would know what parameters to use but it is
> harder for the core to know since this information is not discoverable
> via SFDP.

Ah, I see, thanks for clarification.

-michael

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Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

  reply	other threads:[~2022-03-22  8:19 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-28 11:17 [PATCH v2 0/8] mtd: spi-nor: Rework Octal DTR methods Tudor Ambarus
2022-02-28 11:17 ` Tudor Ambarus
2022-02-28 11:17 ` [PATCH v2 1/8] mtd: spi-nor: Rename method, s/spi_nor_match_id/spi_nor_match_name Tudor Ambarus
2022-02-28 11:17   ` Tudor Ambarus
2022-03-21 11:57   ` Pratyush Yadav
2022-03-21 11:57     ` Pratyush Yadav
2022-03-21 22:14   ` Michael Walle
2022-03-21 22:14     ` Michael Walle
2022-02-28 11:17 ` [PATCH v2 2/8] mtd: spi-nor: Introduce spi_nor_match_id() Tudor Ambarus
2022-02-28 11:17   ` Tudor Ambarus
2022-03-21 12:00   ` Pratyush Yadav
2022-03-21 12:00     ` Pratyush Yadav
2022-03-21 22:15   ` Michael Walle
2022-03-21 22:15     ` Michael Walle
2022-02-28 11:17 ` [PATCH v2 3/8] mtd: spi-nor: core: Use auto-detection only once Tudor Ambarus
2022-02-28 11:17   ` Tudor Ambarus
2022-03-21 12:14   ` Pratyush Yadav
2022-03-21 12:14     ` Pratyush Yadav
2022-03-21 12:50     ` Tudor.Ambarus
2022-03-21 12:50       ` Tudor.Ambarus
2022-03-21 17:42       ` Pratyush Yadav
2022-03-21 17:42         ` Pratyush Yadav
2022-03-21 22:38         ` Michael Walle
2022-03-21 22:38           ` Michael Walle
2022-03-30 18:50           ` Pratyush Yadav
2022-03-30 18:50             ` Pratyush Yadav
2022-02-28 11:17 ` [PATCH v2 4/8] mtd: spi-nor: core: Introduce method for RDID op Tudor Ambarus
2022-02-28 11:17   ` Tudor Ambarus
2022-03-21 12:21   ` Pratyush Yadav
2022-03-21 12:21     ` Pratyush Yadav
2022-03-21 13:18     ` Tudor.Ambarus
2022-03-21 13:18       ` Tudor.Ambarus
2022-03-21 17:39       ` Pratyush Yadav
2022-03-21 17:39         ` Pratyush Yadav
2022-03-30  6:53         ` Tudor.Ambarus
2022-03-30  6:53           ` Tudor.Ambarus
2022-03-30 18:49           ` Pratyush Yadav
2022-03-30 18:49             ` Pratyush Yadav
2022-03-21 22:56   ` Michael Walle
2022-03-21 22:56     ` Michael Walle
2022-03-22  7:32     ` Pratyush Yadav
2022-03-22  7:32       ` Pratyush Yadav
2022-03-22  8:19       ` Michael Walle [this message]
2022-03-22  8:19         ` Michael Walle
2022-02-28 11:17 ` [PATCH v2 5/8] mtd: spi-nor: manufacturers: Use spi_nor_read_id() core method Tudor Ambarus
2022-02-28 11:17   ` Tudor Ambarus
2022-03-21 12:27   ` Pratyush Yadav
2022-03-21 12:27     ` Pratyush Yadav
2022-02-28 11:17 ` [PATCH v2 6/8] mtd: spi-nor: core: Add helpers to read/write any register Tudor Ambarus
2022-02-28 11:17   ` Tudor Ambarus
2022-03-21 23:13   ` Michael Walle
2022-03-21 23:13     ` Michael Walle
2022-04-11  7:29     ` Tudor.Ambarus
2022-04-11  7:29       ` Tudor.Ambarus
2022-02-28 11:17 ` [PATCH v2 7/8] mtd: spi-nor: micron-st: Rework spi_nor_micron_octal_dtr_enable() Tudor Ambarus
2022-02-28 11:17   ` Tudor Ambarus
2022-03-21 12:33   ` Pratyush Yadav
2022-03-21 12:33     ` Pratyush Yadav
2022-02-28 11:17 ` [PATCH v2 8/8] mtd: spi-nor: spansion: Rework spi_nor_cypress_octal_dtr_enable() Tudor Ambarus
2022-02-28 11:17   ` Tudor Ambarus
2022-03-21 12:34   ` Pratyush Yadav
2022-03-21 12:34     ` Pratyush Yadav
2022-03-21 13:19     ` Tudor.Ambarus
2022-03-21 13:19       ` Tudor.Ambarus

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