From: Punit Agrawal <punitagrawal@gmail.com>
To: linux-rockchip@lists.infradead.org, linux-pci@vger.kernel.org
Cc: Punit Agrawal <punitagrawal@gmail.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, alexandru.elisei@arm.com,
wqu@suse.com, robin.murphy@arm.com, pgwipeout@gmail.com,
ardb@kernel.org, briannorris@chromium.org,
shawn.lin@rock-chips.com, helgaas@kernel.org, robh+dt@kernel.org,
Bjorn Helgaas <bhelgaas@google.com>
Subject: [PATCH 1/2] PCI: of: Override 64-bit flag for non-prefetchable memory below 4GB
Date: Fri, 28 May 2021 00:05:41 +0900 [thread overview]
Message-ID: <20210527150541.3130505-2-punitagrawal@gmail.com> (raw)
In-Reply-To: <20210527150541.3130505-1-punitagrawal@gmail.com>
Some host bridges advertise non-prefetable memory windows that are
entirely located below 4GB but are marked as 64-bit address memory.
Since commit 9d57e61bf723 ("of/pci: Add IORESOURCE_MEM_64 to resource
flags for 64-bit memory addresses"), the OF PCI range parser takes a
stricter view and treats 64-bit address ranges as advertised while
before such ranges were treated as 32-bit.
A PCI-to-PCI bridges cannot forward 64-bit non-prefetchable memory
ranges. As a result, the change in behaviour due to the commit causes
allocation failure for devices that are connected behind PCI host
bridges modelled as PCI-to-PCI bridge and require non-prefetchable bus
addresses.
In order to not break platforms, override the 64-bit flag for
non-prefetchable memory ranges that lie entirely below 4GB.
Suggested-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/7a1e2ebc-f7d8-8431-d844-41a9c36a8911@arm.com
Signed-off-by: Punit Agrawal <punitagrawal@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Rob Herring <robh+dt@kernel.org>
---
drivers/pci/of.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index da5b414d585a..b9d0bee5a088 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -565,10 +565,14 @@ static int pci_parse_request_of_pci_ranges(struct device *dev,
case IORESOURCE_MEM:
res_valid |= !(res->flags & IORESOURCE_PREFETCH);
- if (!(res->flags & IORESOURCE_PREFETCH))
+ if (!(res->flags & IORESOURCE_PREFETCH)) {
if (upper_32_bits(resource_size(res)))
dev_warn(dev, "Memory resource size exceeds max for 32 bits\n");
-
+ if ((res->flags & IORESOURCE_MEM_64) && !upper_32_bits(res->end)) {
+ dev_warn(dev, "Overriding 64-bit flag for non-prefetchable memory below 4GB\n");
+ res->flags &= ~IORESOURCE_MEM_64;
+ }
+ }
break;
}
}
--
2.30.2
next prev parent reply other threads:[~2021-05-27 15:08 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-27 15:05 [PATCH 0/2] Fixup non-prefetchable 64-bit host bridge windows Punit Agrawal
2021-05-27 15:05 ` Punit Agrawal [this message]
2021-05-27 16:21 ` [PATCH 1/2] PCI: of: Override 64-bit flag for non-prefetchable memory below 4GB Bjorn Helgaas
2021-05-28 12:42 ` Punit Agrawal
2021-05-27 16:38 ` Rob Herring
2021-05-28 13:24 ` Punit Agrawal
2021-05-27 15:05 ` [PATCH 2/2] arm64: dts: rockchip: Update PCI host bridge window to 32-bit address memory Punit Agrawal
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