From: Boqun Feng <boqun.feng@gmail.com>
To: Bjorn Helgaas <bhelgaas@google.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org,
linux-pci@vger.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>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Rob Herring <robh@kernel.org>, Clint Sbisa <csbisa@amazon.com>,
Boqun Feng <boqun.feng@gmail.com>,
Ard Biesheuvel <ardb@kernel.org>,
Sunil Muthuswamy <sunilmut@microsoft.com>
Subject: [RFC v3 1/7] PCI: Introduce domain_nr in pci_host_bridge
Date: Thu, 10 Jun 2021 00:32:05 +0800 [thread overview]
Message-ID: <20210609163211.3467449-2-boqun.feng@gmail.com> (raw)
In-Reply-To: <20210609163211.3467449-1-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 | 4 +++-
include/linux/pci.h | 10 ++++++++++
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 275204646c68..d2753097a1b0 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 +899,8 @@ 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);
#endif
b = pci_find_bus(pci_domain_nr(bus), bridge->busnr);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 24306504226a..d85d41b5abbd 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:[~2021-06-09 16:32 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-09 16:32 [RFC v3 0/7] PCI: hv: Support host bridge probing on ARM64 Boqun Feng
2021-06-09 16:32 ` Boqun Feng [this message]
2021-06-09 16:32 ` [RFC v3 2/7] PCI: Allow msi domain set-up at host probing time Boqun Feng
2021-06-09 16:32 ` [RFC v3 3/7] PCI: hv: Generify PCI probing Boqun Feng
2021-06-09 16:32 ` [RFC v3 4/7] PCI: hv: Use pci_host_bridge::domain_nr for PCI domain Boqun Feng
2021-06-09 16:32 ` [RFC v3 5/7] PCI: hv: Set up msi domain at bridge probing time Boqun Feng
2021-06-09 16:32 ` [RFC v3 6/7] arm64: PCI: Support root bridge preparation for Hyper-V PCI Boqun Feng
2021-06-09 16:32 ` [RFC v3 7/7] PCI: hv: Turn on the host bridge probing on ARM64 Boqun Feng
2021-06-10 15:01 ` [RFC v3 0/7] PCI: hv: Support " Ard Biesheuvel
2021-06-10 15:42 ` Marc Zyngier
2021-06-10 16:06 ` Boqun Feng
2021-06-10 16:20 ` Marc Zyngier
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