linux-kernel - RE: [PATCH v4] tpm: Enable CLKRUN protocol for Braswell systems

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Date:   Wed, 14 Jun 2017 00:51:25 +0000
From:   "Shaikh, Azhar" <azhar.shaikh@...el.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
CC:     "jgunthorpe@...idianresearch.com" <jgunthorpe@...idianresearch.com>,
        "tpmdd-devel@...ts.sourceforge.net" 
        <tpmdd-devel@...ts.sourceforge.net>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-security-module@...r.kernel.org" 
        <linux-security-module@...r.kernel.org>
Subject: RE: [PATCH v4] tpm: Enable CLKRUN protocol for Braswell systems



> -----Original Message-----
> From: Jarkko Sakkinen [mailto:jarkko.sakkinen@...ux.intel.com]
> Sent: Monday, June 12, 2017 12:50 AM
> To: Shaikh, Azhar <azhar.shaikh@...el.com>
> Cc: jgunthorpe@...idianresearch.com; tpmdd-devel@...ts.sourceforge.net;
> linux-kernel@...r.kernel.org; linux-security-module@...r.kernel.org
> Subject: Re: [PATCH v4] tpm: Enable CLKRUN protocol for Braswell systems
> 
> On Sat, Jun 10, 2017 at 04:35:50PM +0000, Shaikh, Azhar wrote:
> >
> >
> > > -----Original Message-----
> > > From: Jarkko Sakkinen [mailto:jarkko.sakkinen@...ux.intel.com]
> > > Sent: Saturday, June 10, 2017 4:14 AM
> > > To: Shaikh, Azhar <azhar.shaikh@...el.com>
> > > Cc: jgunthorpe@...idianresearch.com;
> > > tpmdd-devel@...ts.sourceforge.net;
> > > linux-kernel@...r.kernel.org; linux-security-module@...r.kernel.org
> > > Subject: Re: [PATCH v4] tpm: Enable CLKRUN protocol for Braswell
> > > systems
> > >
> > > On Thu, Jun 08, 2017 at 04:46:33PM -0700, Azhar Shaikh wrote:
> > > > To overcome a hardware limitation on Intel Braswell systems,
> > > > disable CLKRUN protocol during TPM transactions and re-enable once
> > > > the transaction is completed.
> > > >
> > > > Signed-off-by: Azhar Shaikh <azhar.shaikh@...el.com>
> > > > ---
> > > > Changes from v1:
> > > > - Add CONFIG_X86 around disable_lpc_clk_run () and
> > > > enable_lpc_clk_run() to avoid
> > > > - build breakage on architectures which do not implement
> > > > kmap_atomic_pfn()
> > > >
> > > > Changes from v2:
> > > > - Use ioremap()/iounmap() instead of
> > > kmap_atomic_pfn()/kunmap_atomic()
> > > > - Move is_bsw() and all macros from tpm.h to tpm_tis.c file.
> > > > - Add the is_bsw() check in disable_lpc_clk_run() and
> > > > enable_lpc_clk_run()
> > > > - instead of adding it in each read/write API.
> > > >
> > > > Changes from v3:
> > > > - Move the code under #ifdef CONFIG_X86 and create stub functions
> > > > for everything else
> > > > - Rename the functions disable_lpc_clk_run() ->
> > > > tpm_platform_begin_xfer() and
> > > > - enable_lpc_clk_run() -> tpm_platform_end_xfer()
> > > > - Remove wmb()
> > >
> > > The wrong parameter order in outb() is not worth of mentioning in
> > > your opinion?
> > >
> >
> > Oh yes! It is definitely worth mentioning. I forgot to mention that.
> > Will definitely mention it in the changelog for the next version if any or will
> re send v4 with updated changelog for v3.
> >
> > > Related.
> > >
> > > I looked again the kmap version of the patch and still cannot figure
> > > out what could be wrong. Obviously the wrong outb() cause unexpected
> behavior.
> > >
> > > Do you have chances to grab klog from kmap version with correct outb?
> > >
> >
> > I have not tried the kmap version with corrected outb(). Will give that a try.
> >
> > > /Jarkko
> 
> Thank you!
> 

Even with the corrected outb(), kmap version fails to boot. Could not get boot logs :-(

> /Jarkko