From: Sam Bobroff <sbobroff@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: oohall@gmail.com
Subject: [PATCH 1/1] powerpc/64: Adjust order in pcibios_init()
Date: Thu, 14 Feb 2019 16:14:42 +1100 [thread overview]
Message-ID: <f232553753fe148118646c9013a3d962c19b58ec.1550121250.git.sbobroff@linux.ibm.com> (raw)
The pcibios_init() function for 64 bit PowerPC currently calls
pci_bus_add_devices() before pcibios_resource_survey(), which seems
incorrect because it adds devices and attempts to bind their drivers
before allocating their resources (although no problems seem to be
apparent).
So move the call to pci_bus_add_devices() to after
pcibios_resource_survey().
This will also allow the ppc_md.pcibios_bus_add_device() hooks to
perform actions that depend on PCI resources, both during rescanning
(where this is already the case) and at boot time, which should
support improvements and refactoring.
Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
---
Hi everyone,
I've tested this on a P9 for both the host and a KVM guest, and the change
hasn't caused any differences in PCI resource assignments or the general boot
messages.
I've also had a go at inspecting most of the code used by pci_bus_add_devices()
and pcibios_resource_survey() and it doesn't look like there are going to be
any changes in behaviour caused by reordering. It might be worth mentioning
that the hotplug path (see pcibios_finish_adding_to_bus()) already does
resource allocation before calling pci_bus_add_devices().
However, it would be great if someone could test this change on some older
hardware or comment on wether we should make the same change on 32 bit machines.
Cheers,
Sam.
arch/powerpc/kernel/pci_64.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/pci_64.c b/arch/powerpc/kernel/pci_64.c
index 9d8c10d55407..1ce28888dbdb 100644
--- a/arch/powerpc/kernel/pci_64.c
+++ b/arch/powerpc/kernel/pci_64.c
@@ -58,14 +58,16 @@ static int __init pcibios_init(void)
pci_add_flags(PCI_ENABLE_PROC_DOMAINS | PCI_COMPAT_DOMAIN_0);
/* Scan all of the recorded PCI controllers. */
- list_for_each_entry_safe(hose, tmp, &hose_list, list_node) {
+ list_for_each_entry_safe(hose, tmp, &hose_list, list_node)
pcibios_scan_phb(hose);
- pci_bus_add_devices(hose->bus);
- }
/* Call common code to handle resource allocation */
pcibios_resource_survey();
+ /* Add devices. */
+ list_for_each_entry_safe(hose, tmp, &hose_list, list_node)
+ pci_bus_add_devices(hose->bus);
+
printk(KERN_DEBUG "PCI: Probing PCI hardware done\n");
return 0;
--
2.19.0.2.gcad72f5712
next reply other threads:[~2019-02-14 5:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-14 5:14 Sam Bobroff [this message]
2019-02-15 0:46 ` [PATCH 1/1] powerpc/64: Adjust order in pcibios_init() Oliver
2019-02-22 3:23 ` Sam Bobroff
2019-02-22 4:31 ` Oliver
2019-02-22 5:33 ` Sam Bobroff
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=f232553753fe148118646c9013a3d962c19b58ec.1550121250.git.sbobroff@linux.ibm.com \
--to=sbobroff@linux.ibm.com \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=oohall@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).