[PATCH v9 19/26] PCI: Don't claim fixed BARs

From: Sergei Miroshnichenko <s.miroshnichenko@yadro.com>
To: <linux-pci@vger.kernel.org>
Cc: "Bjorn Helgaas" <helgaas@kernel.org>,
	"Lukas Wunner" <lukas@wunner.de>, "Stefan Roese" <sr@denx.de>,
	"Andy Lavr" <andy.lavr@gmail.com>,
	"Christian König" <christian.koenig@amd.com>,
	"David Laight" <David.Laight@ACULAB.COM>,
	"Rajat Jain" <rajatja@google.com>,
	linux@yadro.com,
	"Sergei Miroshnichenko" <s.miroshnichenko@yadro.com>
Subject: [PATCH v9 19/26] PCI: Don't claim fixed BARs
Date: Fri, 18 Dec 2020 20:40:04 +0300	[thread overview]
Message-ID: <20201218174011.340514-20-s.miroshnichenko@yadro.com> (raw)
In-Reply-To: <20201218174011.340514-1-s.miroshnichenko@yadro.com>

A fixed BAR always has an address, but its parent bridge window can be not
yet calculated (during boot) or temporarily released for re-calculation
(during PCI rescan) when pci_claim_resource() is called.

Apart from that, fixed BARs now have separate guaranteed mechanism of
assigning comparing to usual BARs, so claiming them is not needed.

Return immediately from pci_claim_resource() to prevent a misleading "can't
claim BAR ... no compatible bridge window" error message.

Signed-off-by: Sergei Miroshnichenko <s.miroshnichenko@yadro.com>
---
 drivers/pci/setup-res.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index 6ffda8b94c52..28ec3d8c79c8 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -139,6 +139,9 @@ int pci_claim_resource(struct pci_dev *dev, int resource)
 		return -EINVAL;
 	}
 
+	if (pci_dev_bar_fixed(dev, res))
+		return 0;
+
 	/*
 	 * If we have a shadow copy in RAM, the PCI device doesn't respond
 	 * to the shadow range, so we don't need to claim it, and upstream
-- 
2.24.1

