From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Roger Pau Monne <roger.pau@citrix.com>
Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org,
Andy Shevchenko <andy@kernel.org>,
Mika Westerberg <mika.westerberg@linux.intel.com>,
Linus Walleij <linus.walleij@linaro.org>,
linux-gpio@vger.kernel.org
Subject: Re: [PATCH v2 1/2] intel/pinctrl: check REVID register value for device presence
Date: Wed, 24 Mar 2021 19:01:18 +0200 [thread overview]
Message-ID: <YFtwXj1Q+PRO0asv@smile.fi.intel.com> (raw)
In-Reply-To: <20210324154312.61878-2-roger.pau@citrix.com>
On Wed, Mar 24, 2021 at 04:43:11PM +0100, Roger Pau Monne wrote:
Thanks for a fix! My comments below.
> Use the value read from the REVID register in order to check for the
> presence of the device. A read of all ones is treated as if the device
> is not present, and hence probing is ended.
>
> This fixes an issue when running as a Xen PVH dom0, where the ACPI
> DSDT table is provided unmodified to dom0 and hence contains the
> pinctrl devices, but the MMIO region(s) containing the device
> registers might not be mapped in the guest physical memory map if such
> region(s) are not exposed on a PCI device BAR or marked as reserved in
> the host memory map.
Any particular point that we can use in the Fixes tag?
...
> Suggested-by: Andy Shevchenko <andy@kernel.org>
Hmm... was it that address I have used? In any case I think my @linux.intel.com
is better.
...
> /* Determine community features based on the revision */
> value = readl(regs + REVID);
> + if (value == ~0u)
> + return -ENODATA;
I think -ENODEV is more appropriate here.
Also comment above should be adjusted to explain this check.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2021-03-24 17:02 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-24 15:43 [PATCH v2 0/2] intel/pinctrl: check some registers reads Roger Pau Monne
2021-03-24 15:43 ` [PATCH v2 1/2] intel/pinctrl: check REVID register value for device presence Roger Pau Monne
2021-03-24 17:01 ` Andy Shevchenko [this message]
2021-03-25 8:36 ` Roger Pau Monné
2021-03-24 15:43 ` [PATCH v2 2/2] intel/pinctrl: check capability offset is between MMIO region Roger Pau Monne
2021-03-24 17:02 ` Andy Shevchenko
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