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From: Joakim Tjernlund <Joakim.Tjernlund@infinera.com>
To: "robh+dt@kernel.org" <robh+dt@kernel.org>,
	"computersforpeace@gmail.com" <computersforpeace@gmail.com>,
	"vigneshr@ti.com" <vigneshr@ti.com>,
	"bbrezillon@kernel.org" <bbrezillon@kernel.org>,
	"marek.vasut@gmail.com" <marek.vasut@gmail.com>,
	"dwmw2@infradead.org" <dwmw2@infradead.org>,
	"richard@nod.at" <richard@nod.at>
Cc: "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"arnd@arndb.de" <arnd@arndb.de>,
	"sergei.shtylyov@cogentembedded.com"
	<sergei.shtylyov@cogentembedded.com>,
	"tudor.ambarus@microchip.com" <tudor.ambarus@microchip.com>,
	"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	"nsekhar@ti.com" <nsekhar@ti.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
	"masonccyang@mxic.com.tw" <masonccyang@mxic.com.tw>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC PATCH v2 1/5] mtd: cfi_cmdset_0002: Add support for polling status register
Date: Thu, 21 Mar 2019 18:11:04 +0000	[thread overview]
Message-ID: <f92362a0678b07d22ccc0f271fe3483dc77364a9.camel@infinera.com> (raw)
In-Reply-To: <20190321174548.9288-2-vigneshr@ti.com>

On Thu, 2019-03-21 at 23:15 +0530, Vignesh Raghavendra wrote:
> 
> HyperFlash devices are compliant with CFI AMD/Fujitsu Extended Command
> Set(0x0002) for flash operations, therefore drivers/mtd/chips/cfi_cmdset_0002.c
> can be use as is. But these devices do not support DQ polling method of
> determining chip ready/good status. These flashes provide Status
> Register whose bits can be polled to know status of flash operation.
> 
> Cypress HyperFlash datasheet here[1], talks about CFI Amd/Fujitsu
> Extended Query version 1.5. Bit 0 of "Software Features supported" field
> of CFI Primary Vendor-Specific Extended Query table indicates
> presence/absence of status register and Bit 1 indicates whether or not
> DQ polling is supported. Using these bits, its possible to determine
> whether flash supports DQ polling or need to use Status Register.
> 
> Add support for polling status register to know device ready/status of
> erase/write operations when DQ polling is not supported.

Isn't this new Status scheme just a copy of Intels(cmdset_0001)?
If so I think the new status impl. in 0002 should borrow from 0001 as this is a
hardened and battle tested impl.

I know other modern 0002 chips supports both old and new impl. of Status and I world
guess that we will see more chips with new Status only.

 Jocke
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  reply	other threads:[~2019-03-21 18:11 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-21 17:45 [RFC PATCH v2 0/5] MTD: Add Initial Hyperbus support Vignesh Raghavendra
2019-03-21 17:45 ` [RFC PATCH v2 1/5] mtd: cfi_cmdset_0002: Add support for polling status register Vignesh Raghavendra
2019-03-21 18:11   ` Joakim Tjernlund [this message]
2019-03-25 12:57     ` Vignesh Raghavendra
2019-03-25 13:51       ` Joakim Tjernlund
2019-03-25 17:06         ` Vignesh Raghavendra
2019-03-25 17:24           ` Joakim Tjernlund
2019-04-02  9:03             ` Vignesh Raghavendra
2019-03-24 16:23   ` Sergei Shtylyov
2019-03-21 17:45 ` [RFC PATCH v2 2/5] dt-bindings: mtd: Add binding documentation for Hyperbus memory devices Vignesh Raghavendra
2019-03-24 16:18   ` Sergei Shtylyov
2019-03-25 13:10     ` Vignesh Raghavendra
2019-03-21 17:45 ` [RFC PATCH v2 3/5] mtd: Add support " Vignesh Raghavendra
2019-03-25 20:13   ` Sergei Shtylyov
2019-03-26  7:51     ` Sergei Shtylyov
2019-03-21 17:45 ` [RFC PATCH v2 4/5] dt-bindings: mtd: Add bindings for TI's AM654 Hyperbus memory controller Vignesh Raghavendra
2019-03-21 17:45 ` [RFC PATCH v2 5/5] mtd: hyperbus: Add driver for TI's " Vignesh Raghavendra
2019-03-26 10:40   ` Sergei Shtylyov

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