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From:   Kishon Vijay Abraham I <kishon@ti.com>
To:     Bjorn Helgaas <bhelgaas@google.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Rob Herring <robh+dt@kernel.org>, Jon Mason <jdmason@kudzu.us>,
        Dave Jiang <dave.jiang@intel.com>,
        Allen Hubbe <allenbh@gmail.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
CC:     Mark Rutland <mark.rutland@arm.com>, <kishon@ti.com>,
        <linux-pci@vger.kernel.org>, <linux-doc@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-ntb@googlegroups.com>
Subject: [RFC PATCH 08/21] PCI: endpoint: Make *_get_first_free_bar() take into account 64 bit BAR
Date:   Thu, 26 Sep 2019 16:59:20 +0530
Message-ID: <20190926112933.8922-9-kishon@ti.com>
In-Reply-To: <20190926112933.8922-1-kishon@ti.com>
References: <20190926112933.8922-1-kishon@ti.com>
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Sender: linux-kernel-owner@vger.kernel.org
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pci_epc_get_first_free_bar() uses only "reserved_bar" member in
epc_features to get the first unreserved BAR. However if the
reserved BAR is also a 64-bit BAR, then the next BAR shouldn't be
returned (since 64-bit BAR uses two BARs).

Make pci_epc_get_first_free_bar() take into account 64 bit BAR while
returning the first free unreserved BAR.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
---
 drivers/pci/endpoint/pci-epc-core.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index 0c2fdd39090c..7eae7dcaebf9 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -153,12 +153,20 @@ EXPORT_SYMBOL_GPL(of_pci_epc_get_by_name);
 unsigned int pci_epc_get_first_free_bar(const struct pci_epc_features
 					*epc_features)
 {
-	int free_bar;
+	unsigned long free_bar;
 
 	if (!epc_features)
 		return 0;
 
-	free_bar = ffz(epc_features->reserved_bar);
+	/* Find if the reserved BAR is also a 64-bit BAR */
+	free_bar = epc_features->reserved_bar & epc_features->bar_fixed_64bit;
+
+	/* Set the adjacent bit if the reserved BAR is also a 64-bit BAR */
+	free_bar <<= 1;
+	free_bar |= epc_features->reserved_bar;
+
+	/* Now find the free BAR */
+	free_bar = ffz(free_bar);
 	if (free_bar > 5)
 		return 0;
 
-- 
2.17.1