Re: [tpmdd-devel] [PATCH v2 0/3] tpm_tis: Clean up force module parameter

From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: "Wilck, Martin" <martin.wilck@ts.fujitsu.com>
Cc: "Jason Gunthorpe" <jgunthorpe@obsidianresearch.com>,
	"tpmdd-devel@lists.sourceforge.net"
	<tpmdd-devel@lists.sourceforge.net>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Subject: Re: [tpmdd-devel] [PATCH v2 0/3] tpm_tis: Clean up force module parameter
Date: Mon, 7 Dec 2015 12:16:36 +0200	[thread overview]
Message-ID: <20151207101635.GA20456@intel.com> (raw)
In-Reply-To: <C5A28EF7B98F574C85C70238C8E9ECC04E682BF17D@ABGEX74E.FSC.NET>

On Mon, Dec 07, 2015 at 10:52:51AM +0100, Wilck, Martin wrote:
> > > > You can completely ignore this question. I saw Martins reply with a fix for
> > > > "tpm_tis: Use devm_ioremap_resource" that you should squash into that
> > > > change. So it's proved that TPM ACPI device objects do not always have a
> > > > memory resource. Good.
> > > 
> > > Repeat, the memory resource DOES exist on my system. Not sure what proof
> > > you saw there.
> > 
> > Ok, lets go this through.
> > 
> > I deduced this from two facts:
> > 
> > * It used to have memory resource as conditional and as a fallback use
> >   fixed value.
> > * Your workaround reverted the situation to this.
> > 
> > Did I understand something incorrectly?
> 
> The problem in my case didn't occur because ACPI was lacking a resource.
> It has one "extra" resource that Jason's original code didn't
> recognize. 
> 
> Jason's code was wrongly assuming that a resource that isn't of type
> "IRQ" has to be of type "MEMORY". If I print out the resource types
> encountered in tpm_check_resource(), I get
> ACPI_RESOURCE_TYPE_FIXED_MEMORY32  (0x0a) first, followed by
> ACPI_RESOURCE_TYPE_END_TAG (0x07). The latter was mistakenly used by
> Jason't code as a memory resource. This is how ACPI ResourceTemplates
> work (a list with an end marker). The correct solution is to always
> check the return value of acpi_dev_resource_memory(), as it's currently
> implemented in Jason't current "for-jarkko" branch.

Aah. Right.

> Martin

/Jarkko