linux-kernel - Re: [PATCH] mtd: bcm47xxsflash: use devm_ioremap

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Message-ID: <CACna6rx26JEWSvckzzNdZ=XVySW9R6jbH-mkbc2JPxTrwJZWzg@mail.gmail.com>
Date:	Sun, 24 Jan 2016 22:31:21 +0100
From:	Rafał Miłecki <zajec5@...il.com>
To:	"Maciej W. Rozycki" <macro@...tec.com>
Cc:	Brian Norris <computersforpeace@...il.com>,
	Ralf Baechle <ralf@...ux-mips.org>,
	Javier Martinez Canillas <javier@....samsung.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Fengguang Wu <fengguang.wu@...el.com>,
	Michael Ellerman <mpe@...erman.id.au>,
	Luis de Bethencourt <luisbg@....samsung.com>,
	Jeremy Kerr <jk@...abs.org>,
	Neelesh Gupta <neelegup@...ux.vnet.ibm.com>,
	"linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
	David Woodhouse <dwmw2@...radead.org>,
	Cyril Bur <cyrilbur@...il.com>,
	"Maciej W. Rozycki" <macro@...ux-mips.org>
Subject: Re: [PATCH] mtd: bcm47xxsflash: use devm_ioremap_nocache() instead of KSEG0ADDR()

On 24 January 2016 at 21:26, Maciej W. Rozycki <macro@...tec.com> wrote:
> On Sat, 23 Jan 2016, Brian Norris wrote:
>
>> IIUC, this could be solved by:
>> (a) using an uncached mapping or
>> (b) explicitly invalidating the relevant region after doing flash writes
>> or erasures
>
>  Flash writes are usually much, much less frequent than reads, so
> optimising for reads is IMO the right direction.  So a cached mapping is a
> good choice, however invalidation must then be done after a write.

Can you give me some hint where to look at for cache invalidation?

-- 
Rafał