linux-kernel - [PATCH v9 02/17] PCI: endpoint: Make *_get_first_free

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Date:   Mon, 4 Jan 2021 20:58:54 +0530
From:   Kishon Vijay Abraham I <kishon@...com>
To:     Bjorn Helgaas <bhelgaas@...gle.com>,
        Jonathan Corbet <corbet@....net>,
        Kishon Vijay Abraham I <kishon@...com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Arnd Bergmann <arnd@...db.de>, Jon Mason <jdmason@...zu.us>,
        Dave Jiang <dave.jiang@...el.com>,
        Allen Hubbe <allenbh@...il.com>,
        Tom Joseph <tjoseph@...ence.com>, Rob Herring <robh@...nel.org>
CC:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        <linux-pci@...r.kernel.org>, <linux-doc@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <linux-ntb@...glegroups.com>
Subject: [PATCH v9 02/17] PCI: endpoint: Make *_get_first_free_bar() take into account 64 bit BAR

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@...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 cadd3db0cbb0..25e57672e1a1 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -93,12 +93,20 @@ EXPORT_SYMBOL_GPL(pci_epc_get);
 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