diff mbox series

PCI/portdrv: Use link bandwidth notification capability bit

Message ID 20210512184050.2915-1-stuart.w.hayes@gmail.com
State New
Headers show
Series PCI/portdrv: Use link bandwidth notification capability bit | expand

Commit Message

Stuart Hayes May 12, 2021, 6:40 p.m. UTC
The pcieport driver can fail to attach to a downstream port that doesn't
support bandwidth notificaion.  This can happen when, in
pcie_port_device_register(), pci_init_service_irqs() tries (and fails) to
set up a bandwidth notificaion IRQ for a device that doesn't support it.

This patch changes get_port_device_capability() to look at the link
bandwidth notification capability bit in the link capabilities register of
the port, instead of assuming that all downstream ports have that
capability.

Signed-off-by: Stuart Hayes <stuart.w.hayes@gmail.com>
---
 drivers/pci/pcie/portdrv_core.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

Comments

Lukas Wunner May 12, 2021, 7:54 p.m. UTC | #1
On Thu, May 13, 2021 at 12:10:50AM +0530, Stuart Hayes wrote:
> The pcieport driver can fail to attach to a downstream port that doesn't
> support bandwidth notificaion.  This can happen when, in
                    ^^^^^^^^^^^
		    notification

> pcie_port_device_register(), pci_init_service_irqs() tries (and fails) to
> set up a bandwidth notificaion IRQ for a device that doesn't support it.
                     ^^^^^^^^^^^
		     notification

> --- a/drivers/pci/pcie/portdrv_core.c
> +++ b/drivers/pci/pcie/portdrv_core.c
> @@ -257,8 +257,13 @@ static int get_port_device_capability(struct pci_dev *dev)
>  		services |= PCIE_PORT_SERVICE_DPC;
>  
>  	if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM ||
> -	    pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
> -		services |= PCIE_PORT_SERVICE_BWNOTIF;
> +	    pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) {
> +		u32 linkcap;
> +
> +		pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &linkcap);
> +		if (linkcap & PCI_EXP_LNKCAP_LBNC)
> +			services |= PCIE_PORT_SERVICE_BWNOTIF;
> +	}

This *could* be #ifdef'ed to CONFIG_PCIE_BW (like CONFIG_PCIEAER a bit
further above in this function).

Apart from those nits,
Reviewed-by: Lukas Wunner <lukas@wunner.de>
diff mbox series

Patch

diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index e1fed6649c41..3ee63968deaa 100644
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -257,8 +257,13 @@  static int get_port_device_capability(struct pci_dev *dev)
 		services |= PCIE_PORT_SERVICE_DPC;
 
 	if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM ||
-	    pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
-		services |= PCIE_PORT_SERVICE_BWNOTIF;
+	    pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) {
+		u32 linkcap;
+
+		pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &linkcap);
+		if (linkcap & PCI_EXP_LNKCAP_LBNC)
+			services |= PCIE_PORT_SERVICE_BWNOTIF;
+	}
 
 	return services;
 }