From: Caleb James DeLisle <cjd@cjdns.fr>
To: linux-mips@vger.kernel.org
Cc: naseefkm@gmail.com, mturquette@baylibre.com, sboyd@kernel.org,
robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org,
cjd@cjdns.fr, tsbogend@alpha.franken.de, ryder.lee@mediatek.com,
jianjun.wang@mediatek.com, lpieralisi@kernel.org,
kwilczynski@kernel.org, mani@kernel.org, bhelgaas@google.com,
vkoul@kernel.org, neil.armstrong@linaro.org,
p.zabel@pengutronix.de, matthias.bgg@gmail.com,
angelogioacchino.delregno@collabora.com, nbd@nbd.name,
ansuelsmth@gmail.com, linux-clk@vger.kernel.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org, linux-mediatek@lists.infradead.org,
linux-phy@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
Bjorn Helgaas <helgaas@kernel.org>
Subject: [PATCH v2 7/8] PCI: Skip bridge window reads when window is not supported
Date: Mon, 9 Mar 2026 13:18:17 +0000 [thread overview]
Message-ID: <20260309131818.74467-8-cjd@cjdns.fr> (raw)
In-Reply-To: <20260309131818.74467-1-cjd@cjdns.fr>
pci_read_bridge_io() and pci_read_bridge_mmio_pref() read bridge window
registers unconditionally. If the registers are hardwired to zero
(not implemented), both base and limit will be 0. Since (0 <= 0) is
true, a bogus window [mem 0x00000000-0x000fffff] or [io 0x0000-0x0fff]
gets created.
pci_read_bridge_windows() already detects unsupported windows by
testing register writability and sets io_window/pref_window flags
accordingly. Check these flags at the start of pci_read_bridge_io()
and pci_read_bridge_mmio_pref() to skip reading registers when the
window is not supported.
Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
Link: https://lore.kernel.org/all/20260113210259.GA715789@bhelgaas/
Signed-off-by: Ahmed Naseef <naseefkm@gmail.com>
Signed-off-by: Caleb James DeLisle <cjd@cjdns.fr>
---
drivers/pci/probe.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index bccc7a4bdd79..4eacb741b4ec 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -395,6 +395,9 @@ static void pci_read_bridge_io(struct pci_dev *dev, struct resource *res,
unsigned long io_mask, io_granularity, base, limit;
struct pci_bus_region region;
+ if (!dev->io_window)
+ return;
+
io_mask = PCI_IO_RANGE_MASK;
io_granularity = 0x1000;
if (dev->io_window_1k) {
@@ -465,6 +468,9 @@ static void pci_read_bridge_mmio_pref(struct pci_dev *dev, struct resource *res,
pci_bus_addr_t base, limit;
struct pci_bus_region region;
+ if (!dev->pref_window)
+ return;
+
pci_read_config_word(dev, PCI_PREF_MEMORY_BASE, &mem_base_lo);
pci_read_config_word(dev, PCI_PREF_MEMORY_LIMIT, &mem_limit_lo);
base64 = (mem_base_lo & PCI_PREF_RANGE_MASK) << 16;
--
2.39.5
next prev parent reply other threads:[~2026-03-09 13:19 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-09 13:18 [PATCH v2 0/8] mips: econet: Add clk/reset and PCIe support Caleb James DeLisle
2026-03-09 13:18 ` [PATCH v2 1/8] dt-bindings: clock, reset: Add econet EN751221 Caleb James DeLisle
2026-03-10 8:21 ` Krzysztof Kozlowski
2026-03-10 8:37 ` Caleb James DeLisle
2026-03-10 8:51 ` Krzysztof Kozlowski
2026-03-09 13:18 ` [PATCH v2 2/8] clk: airoha: Add econet EN751221 clock/reset support to en7523-scu Caleb James DeLisle
2026-03-11 14:39 ` Brian Masney
2026-03-11 17:12 ` Caleb James DeLisle
2026-03-11 19:44 ` Brian Masney
2026-03-09 13:18 ` [PATCH v2 3/8] dt-bindings: phy: Document PCIe PHY in EcoNet EN751221 and EN7528 Caleb James DeLisle
2026-03-10 8:24 ` Krzysztof Kozlowski
2026-03-10 10:37 ` Caleb James DeLisle
2026-03-10 10:40 ` Krzysztof Kozlowski
2026-03-10 10:40 ` Krzysztof Kozlowski
2026-03-10 11:13 ` Caleb James DeLisle
2026-03-10 11:20 ` Krzysztof Kozlowski
2026-03-09 13:18 ` [PATCH v2 4/8] phy: econet: Add PCIe PHY driver for EcoNet EN751221 and EN7528 SoCs Caleb James DeLisle
2026-03-09 13:18 ` [PATCH v2 5/8] dt-bindings: PCI: mediatek: Add support for EcoNet EN7528 Caleb James DeLisle
2026-03-10 8:25 ` Krzysztof Kozlowski
2026-03-10 8:49 ` Caleb James DeLisle
2026-03-09 13:18 ` [PATCH v2 6/8] PCI: mediatek: Add support for EcoNet EN7528 SoC Caleb James DeLisle
2026-03-09 13:18 ` Caleb James DeLisle [this message]
2026-03-09 13:18 ` [PATCH v2 8/8] mips: dts: Add PCIe to EcoNet EN751221 Caleb James DeLisle
2026-04-06 12:37 ` Thomas Bogendoerfer
2026-04-08 12:58 ` Caleb James DeLisle
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