From: Brian Norris <computersforpeace@gmail.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Wan ZongShun <mcuos.com@gmail.com>,
David Woodhouse <dwmw2@infradead.org>,
linux-arm-kernel@lists.infradead.org,
linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mtd: nuc900_nand: read correct SMISR register
Date: Wed, 13 Jan 2016 13:50:13 -0800 [thread overview]
Message-ID: <20160113215013.GS109450@google.com> (raw)
In-Reply-To: <9019174.GYajdpGP8V@wuerfel>
On Wed, Jan 13, 2016 at 10:38:08PM +0100, Arnd Bergmann wrote:
> The nuc900_nand driver has always passed an incorrect register
> address in its nuc900_check_rb() function, which cannot possibly
> work, and in some configurations gives us a build warning:
>
> drivers/mtd/nand/nuc900_nand.c: In function 'nuc900_check_rb':
> drivers/mtd/nand/nuc900_nand.c:27:23: warning: passing argument 1 of '__raw_readl' makes pointer from integer without a cast [-Wint-conversion]
> #define REG_SMISR 0xac
> drivers/mtd/nand/nuc900_nand.c:118:20: note: in expansion of macro 'REG_SMISR'
> val = __raw_readl(REG_SMISR);
>
> This makes sure we actually read from the register rather than
> from (void *)0x000000ac in user space.
>
> I suspect nobody noticed this before because the nuc900_nand_devready()
> function never gets called, or nobody uses this driver on an upstream
> kernel. Possibly even both.
Almost definitely not the first. That's an absolutely essential
function for this driver (it doesn't have ->waitfunc(), so we use
->dev_ready() all the time). Quite likely the latter.
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>
> diff --git a/drivers/mtd/nand/nuc900_nand.c b/drivers/mtd/nand/nuc900_nand.c
> index 220ddfcf29f5..dbc5b571c2bb 100644
> --- a/drivers/mtd/nand/nuc900_nand.c
> +++ b/drivers/mtd/nand/nuc900_nand.c
> @@ -113,7 +113,7 @@ static int nuc900_check_rb(struct nuc900_nand *nand)
> {
> unsigned int val;
> spin_lock(&nand->lock);
> - val = __raw_readl(REG_SMISR);
> + val = __raw_readl(nand->reg + REG_SMISR);
> val &= READYBUSY;
> spin_unlock(&nand->lock);
>
Looks OK to me, though I kinda hate dragging on support for
obviously-unused drivers...
Brian
WARNING: multiple messages have this Message-ID (diff)
From: computersforpeace@gmail.com (Brian Norris)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] mtd: nuc900_nand: read correct SMISR register
Date: Wed, 13 Jan 2016 13:50:13 -0800 [thread overview]
Message-ID: <20160113215013.GS109450@google.com> (raw)
In-Reply-To: <9019174.GYajdpGP8V@wuerfel>
On Wed, Jan 13, 2016 at 10:38:08PM +0100, Arnd Bergmann wrote:
> The nuc900_nand driver has always passed an incorrect register
> address in its nuc900_check_rb() function, which cannot possibly
> work, and in some configurations gives us a build warning:
>
> drivers/mtd/nand/nuc900_nand.c: In function 'nuc900_check_rb':
> drivers/mtd/nand/nuc900_nand.c:27:23: warning: passing argument 1 of '__raw_readl' makes pointer from integer without a cast [-Wint-conversion]
> #define REG_SMISR 0xac
> drivers/mtd/nand/nuc900_nand.c:118:20: note: in expansion of macro 'REG_SMISR'
> val = __raw_readl(REG_SMISR);
>
> This makes sure we actually read from the register rather than
> from (void *)0x000000ac in user space.
>
> I suspect nobody noticed this before because the nuc900_nand_devready()
> function never gets called, or nobody uses this driver on an upstream
> kernel. Possibly even both.
Almost definitely not the first. That's an absolutely essential
function for this driver (it doesn't have ->waitfunc(), so we use
->dev_ready() all the time). Quite likely the latter.
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>
> diff --git a/drivers/mtd/nand/nuc900_nand.c b/drivers/mtd/nand/nuc900_nand.c
> index 220ddfcf29f5..dbc5b571c2bb 100644
> --- a/drivers/mtd/nand/nuc900_nand.c
> +++ b/drivers/mtd/nand/nuc900_nand.c
> @@ -113,7 +113,7 @@ static int nuc900_check_rb(struct nuc900_nand *nand)
> {
> unsigned int val;
> spin_lock(&nand->lock);
> - val = __raw_readl(REG_SMISR);
> + val = __raw_readl(nand->reg + REG_SMISR);
> val &= READYBUSY;
> spin_unlock(&nand->lock);
>
Looks OK to me, though I kinda hate dragging on support for
obviously-unused drivers...
Brian
next prev parent reply other threads:[~2016-01-13 21:50 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-13 21:38 [PATCH] mtd: nuc900_nand: read correct SMISR register Arnd Bergmann
2016-01-13 21:38 ` Arnd Bergmann
2016-01-13 21:50 ` Brian Norris [this message]
2016-01-13 21:50 ` Brian Norris
2016-01-13 22:02 ` Arnd Bergmann
2016-01-13 22:02 ` Arnd Bergmann
2016-01-14 0:29 ` Brian Norris
2016-01-14 0:29 ` Brian Norris
2016-01-14 9:34 ` Wan Zongshun
2016-01-14 9:34 ` Wan Zongshun
2016-01-14 12:08 ` Arnd Bergmann
2016-01-14 12:08 ` Arnd Bergmann
2016-01-15 7:53 ` Wan Zongshun
2016-01-15 7:53 ` Wan Zongshun
2016-01-15 11:03 ` Arnd Bergmann
2016-01-15 11:03 ` Arnd Bergmann
2016-01-15 15:01 ` Wan Zongshun
2016-01-15 15:01 ` Wan Zongshun
2016-01-15 18:03 ` Brian Norris
2016-01-15 18:03 ` Brian Norris
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