From:   Kishon Vijay Abraham I <kishon@ti.com>
To:     Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Rob Herring <robh@kernel.org>,
        =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= <kw@linux.com>,
        Bjorn Helgaas <bhelgaas@google.com>
CC:     <linux-pci@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        Kishon Vijay Abraham I <kishon@ti.com>,
        <devicetree@vger.kernel.org>
Subject: [PATCH v2 4/5] PCI: keystone: Add quirk to mark AM654 RC BAR flag as IORESOURCE_UNSET
Date:   Fri, 26 Nov 2021 14:01:18 +0530
Message-ID: <20211126083119.16570-5-kishon@ti.com>
In-Reply-To: <20211126083119.16570-1-kishon@ti.com>
References: <20211126083119.16570-1-kishon@ti.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

AM654 RootComplex has a hard coded 64 bit BAR of size 1MB and also has
both MSI and MSI-X capability in it's config space. If PCIEPORTBUS is
enabled, it tries to configure MSI-X and msix_mask_all() adds about 10
Second boot up delay when it tries to write to undefined location.

Add quirk to mark AM654 RC BAR flag as IORESOURCE_UNSET so that
msix_map_region() returns NULL for Root Complex and avoid un-desirable
writes to MSI-X table.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
---
 drivers/pci/controller/dwc/pci-keystone.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c
index 52d20fe17ee9..73e6626a0d8f 100644
--- a/drivers/pci/controller/dwc/pci-keystone.c
+++ b/drivers/pci/controller/dwc/pci-keystone.c
@@ -557,8 +557,14 @@ static void ks_pcie_quirk(struct pci_dev *dev)
 		{ 0, },
 	};
 
-	if (pci_is_root_bus(bus))
+	if (pci_is_root_bus(bus)) {
 		bridge = dev;
+		if (pci_match_id(am6_pci_devids, bridge)) {
+			struct resource *r = &dev->resource[0];
+
+			r->flags |= IORESOURCE_UNSET;
+		}
+	}
 
 	/* look for the host bridge */
 	while (!pci_is_root_bus(bus)) {
-- 
2.17.1