From: Boqun Feng <boqun.feng@gmail.com>
To: Bjorn Helgaas <bhelgaas@google.com>,
Arnd Bergmann <arnd@arndb.de>, Marc Zyngier <maz@kernel.org>
Cc: "Catalin Marinas" <catalin.marinas@arm.com>,
"Will Deacon" <will@kernel.org>,
"K. Y. Srinivasan" <kys@microsoft.com>,
"Haiyang Zhang" <haiyangz@microsoft.com>,
"Stephen Hemminger" <sthemmin@microsoft.com>,
"Wei Liu" <wei.liu@kernel.org>,
"Dexuan Cui" <decui@microsoft.com>,
"Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>,
"Rob Herring" <robh@kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Boqun Feng" <boqun.feng@gmail.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org,
linux-pci@vger.kernel.org,
"Sunil Muthuswamy" <sunilmut@microsoft.com>,
"Mike Rapoport" <rppt@kernel.org>
Subject: [RFC v4 1/7] PCI: Introduce domain_nr in pci_host_bridge
Date: Wed, 14 Jul 2021 18:27:31 +0800 [thread overview]
Message-ID: <20210714102737.198432-2-boqun.feng@gmail.com> (raw)
In-Reply-To: <20210714102737.198432-1-boqun.feng@gmail.com>
Currently we retrieve the PCI domain number of the host bridge from the
bus sysdata (or pci_config_window if PCI_DOMAINS_GENERIC=y). Actually
we have the information at PCI host bridge probing time, and it makes
sense that we store it into pci_host_bridge. One benefit of doing so is
the requirement for supporting PCI on Hyper-V for ARM64, because the
host bridge of Hyper-V doesn't have pci_config_window, whereas ARM64 is
a PCI_DOMAINS_GENERIC=y arch, so we cannot retrieve the PCI domain
number from pci_config_window on ARM64 Hyper-V guest.
As the preparation for ARM64 Hyper-V PCI support, we introduce the
domain_nr in pci_host_bridge and a sentinel value to allow drivers to
set domain numbers properly at probing time. Currently
CONFIG_PCI_DOMAINS_GENERIC=y archs are only users of this
newly-introduced field.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
drivers/pci/probe.c | 6 +++++-
include/linux/pci.h | 10 ++++++++++
2 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 79177ac37880..60c50d4f156f 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -594,6 +594,7 @@ static void pci_init_host_bridge(struct pci_host_bridge *bridge)
bridge->native_pme = 1;
bridge->native_ltr = 1;
bridge->native_dpc = 1;
+ bridge->domain_nr = PCI_DOMAIN_NR_NOT_SET;
device_initialize(&bridge->dev);
}
@@ -898,7 +899,10 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge)
bus->ops = bridge->ops;
bus->number = bus->busn_res.start = bridge->busnr;
#ifdef CONFIG_PCI_DOMAINS_GENERIC
- bus->domain_nr = pci_bus_find_domain_nr(bus, parent);
+ if (bridge->domain_nr == PCI_DOMAIN_NR_NOT_SET)
+ bus->domain_nr = pci_bus_find_domain_nr(bus, parent);
+ else
+ bus->domain_nr = bridge->domain_nr;
#endif
b = pci_find_bus(pci_domain_nr(bus), bridge->busnr);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 540b377ca8f6..952bb7d46576 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -526,6 +526,15 @@ static inline int pci_channel_offline(struct pci_dev *pdev)
return (pdev->error_state != pci_channel_io_normal);
}
+/*
+ * PCI Conventional has at most 256 PCI bus segments and PCI Express has at
+ * most 65536 "PCI Segments Groups", therefore -1 is not a valid PCI domain
+ * number, and can be used as a sentinel value indicating ->domain_nr is not
+ * set by the driver (and CONFIG_PCI_DOMAINS_GENERIC=y can set it in generic
+ * code).
+ */
+#define PCI_DOMAIN_NR_NOT_SET (-1)
+
struct pci_host_bridge {
struct device dev;
struct pci_bus *bus; /* Root bus */
@@ -533,6 +542,7 @@ struct pci_host_bridge {
struct pci_ops *child_ops;
void *sysdata;
int busnr;
+ int domain_nr;
struct list_head windows; /* resource_entry */
struct list_head dma_ranges; /* dma ranges resource list */
u8 (*swizzle_irq)(struct pci_dev *, u8 *); /* Platform IRQ swizzler */
--
2.30.2
next prev parent reply other threads:[~2021-07-14 10:29 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-14 10:27 [RFC v4 0/7] PCI: hv: Support host bridge probing on ARM64 Boqun Feng
2021-07-14 10:27 ` Boqun Feng [this message]
2021-07-14 19:33 ` [RFC v4 1/7] PCI: Introduce domain_nr in pci_host_bridge Bjorn Helgaas
2021-07-15 17:30 ` Boqun Feng
2021-07-15 19:07 ` Bjorn Helgaas
2021-07-15 19:11 ` Arnd Bergmann
2021-07-14 10:27 ` [RFC v4 2/7] PCI: Allow msi domain set-up at host probing time Boqun Feng
2021-07-14 19:39 ` Bjorn Helgaas
2021-07-14 10:27 ` [RFC v4 3/7] arm64: PCI: Support root bridge preparation for Hyper-V PCI Boqun Feng
2021-07-14 19:46 ` Bjorn Helgaas
2021-07-14 10:27 ` [RFC v4 4/7] PCI: hv: Generify PCI probing Boqun Feng
2021-07-14 19:49 ` Bjorn Helgaas
2021-07-14 10:27 ` [RFC v4 5/7] PCI: hv: Use pci_host_bridge::domain_nr for PCI domain Boqun Feng
2021-07-14 17:04 ` [EXTERNAL] " Sunil Muthuswamy
2021-07-15 3:59 ` Boqun Feng
2021-07-14 10:27 ` [RFC v4 6/7] PCI: hv: Set up msi domain at bridge probing time Boqun Feng
2021-07-14 10:27 ` [RFC v4 7/7] PCI: hv: Turn on the host bridge probing on ARM64 Boqun Feng
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