You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
63 lines
2.4 KiB
63 lines
2.4 KiB
![]()
7 years ago
|
From patchwork Tue Jan 9 14:42:21 2018
|
||
|
Content-Type: text/plain; charset="utf-8"
|
||
|
MIME-Version: 1.0
|
||
|
Content-Transfer-Encoding: 7bit
|
||
|
Subject: PCI: dwc: fix enumeration end when reaching root subordinate
|
||
|
From: Koen Vandeputte <koen.vandeputte@ncentric.com>
|
||
|
X-Patchwork-Id: 10152443
|
||
|
Message-Id: <1515508941-20055-1-git-send-email-koen.vandeputte@ncentric.com>
|
||
|
To: linux-pci@vger.kernel.org
|
||
|
Cc: bhelgaas@google.com, lorenzo.pieralisi@arm.com,
|
||
|
Joao.Pinto@synopsys.com, jingoohan1@gmail.com, niklas.cassel@axis.com,
|
||
|
Koen Vandeputte <koen.vandeputte@ncentric.com>,
|
||
|
Mika Westerberg <mika.westerberg@linux.intel.com>
|
||
|
Date: Tue, 9 Jan 2018 15:42:21 +0100
|
||
|
|
||
|
The subordinate value indicates the highest bus number which can be
|
||
|
reached downstream though a certain device.
|
||
|
|
||
|
Commit a20c7f36bd3d ("PCI: Do not allocate more buses than available in
|
||
|
parent")
|
||
|
ensures that downstream devices cannot assign busnumbers higher than the
|
||
|
upstream device subordinate number, which was indeed illogical.
|
||
|
|
||
|
By default, dw_pcie_setup_rc() inits the Root Complex subordinate to a
|
||
|
value of 0x01.
|
||
|
|
||
|
Due to this combined with above commit, enumeration stops digging deeper
|
||
|
downstream as soon as bus num 0x01 has been assigned, which is always
|
||
|
the case for a bridge device.
|
||
|
|
||
|
This results in all devices behind a bridge bus to remain undetected, as
|
||
|
these would be connected to bus 0x02 or higher.
|
||
|
|
||
|
Fix this by initializing the RC to a subordinate value of 0xff, meaning
|
||
|
that all busses [0x00-0xff] are reachable through this RC.
|
||
|
|
||
|
Fixes: a20c7f36bd3d ("PCI: Do not allocate more buses than available in
|
||
|
parent")
|
||
|
Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
|
||
|
Tested-by: Niklas Cassel <niklas.cassel@axis.com>
|
||
|
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
|
||
|
---
|
||
|
|
||
|
Will send separate patches to stable as this file got moved/renamed
|
||
|
|
||
|
|
||
|
drivers/pci/dwc/pcie-designware-host.c | 2 +-
|
||
|
1 file changed, 1 insertion(+), 1 deletion(-)
|
||
|
|
||
|
diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c
|
||
|
index bf558df5b7b3..2b5470173196 100644
|
||
|
--- a/drivers/pci/dwc/pcie-designware-host.c
|
||
|
+++ b/drivers/pci/dwc/pcie-designware-host.c
|
||
|
@@ -616,7 +616,7 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
|
||
|
/* setup bus numbers */
|
||
|
val = dw_pcie_readl_dbi(pci, PCI_PRIMARY_BUS);
|
||
|
val &= 0xff000000;
|
||
|
- val |= 0x00010100;
|
||
|
+ val |= 0x00ff0100;
|
||
|
dw_pcie_writel_dbi(pci, PCI_PRIMARY_BUS, val);
|
||
|
|
||
|
/* setup command register */
|