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authorKoen Vandeputte <koen.vandeputte@ncentric.com>2018-03-07 10:46:39 -0600
committerBjorn Helgaas <bhelgaas@google.com>2018-03-07 10:46:39 -0600
commitfc110ebdd014dd1368c98e7685b47789c31fab42 (patch)
tree628d6c4faac910596af396b275d1c775c75f0735
parenta6f1086e29e93621a6394b94b8c0e4a4e490f38b (diff)
PCI: dwc: Fix enumeration end when reaching root subordinate
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 remaining undetected, as these would be connected to bus 0x02 or higher. Fix this by initializing the RC to a subordinate value of 0xff, which is not altering hardware behaviour in any way, but informs probing function pci_scan_bridge() later on which reads this value back from register. The following nasty errors during boot are also fixed by this: pci_bus 0000:02: busn_res: can not insert [bus 02-ff] under [bus 01] (conflicts with (null) [bus 01]) ... pci_bus 0000:03: [bus 03] partially hidden behind bridge 0000:01 [bus 01] ... pci_bus 0000:04: [bus 04] partially hidden behind bridge 0000:01 [bus 01] ... pci_bus 0000:05: [bus 05] partially hidden behind bridge 0000:01 [bus 01] pci_bus 0000:02: busn_res: [bus 02-ff] end is updated to 05 pci_bus 0000:02: busn_res: can not insert [bus 02-05] under [bus 01] (conflicts with (null) [bus 01]) pci_bus 0000:02: [bus 02-05] partially hidden behind bridge 0000:01 [bus 01] Fixes: a20c7f36bd3d ("PCI: Do not allocate more buses than available in parent") Tested-by: Niklas Cassel <niklas.cassel@axis.com> Tested-by: Fabio Estevam <fabio.estevam@nxp.com> Tested-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk> Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Acked-by: Lucas Stach <l.stach@pengutronix.de> Cc: stable@vger.kernel.org # v4.15+ Cc: Binghui Wang <wangbinghui@hisilicon.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Jianguo Sun <sunjianguo1@huawei.com> Cc: Jingoo Han <jingoohan1@gmail.com> Cc: Kishon Vijay Abraham I <kishon@ti.com> Cc: Lucas Stach <l.stach@pengutronix.de> Cc: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Minghuan Lian <minghuan.Lian@freescale.com> Cc: Mingkai Hu <mingkai.hu@freescale.com> Cc: Murali Karicheri <m-karicheri2@ti.com> Cc: Pratyush Anand <pratyush.anand@gmail.com> Cc: Richard Zhu <hongxing.zhu@nxp.com> Cc: Roy Zang <tie-fei.zang@freescale.com> Cc: Shawn Guo <shawn.guo@linaro.org> Cc: Stanimir Varbanov <svarbanov@mm-sol.com> Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Cc: Xiaowei Song <songxiaowei@hisilicon.com> Cc: Zhou Wang <wangzhou1@hisilicon.com>
-rw-r--r--drivers/pci/dwc/pcie-designware-host.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c
index 8de2d5c69b1d..dc9303abda42 100644
--- a/drivers/pci/dwc/pcie-designware-host.c
+++ b/drivers/pci/dwc/pcie-designware-host.c
@@ -613,7 +613,7 @@ 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 */