diff mbox series

[v5,1/9] PCI: mediatek: Using slot's devfn for compare to fix mtk_pcie_find_port logic

Message ID 1538129080-8206-2-git-send-email-honghui.zhang@mediatek.com (mailing list archive)
State New, archived
Delegated to: Bjorn Helgaas
Headers show
Series PCI: mediatek: fixup find_port, enable_msi and add pm, module support | expand

Commit Message

Honghui Zhang Sept. 28, 2018, 10:04 a.m. UTC 
From: Honghui Zhang <honghui.zhang@mediatek.com>

The Mediatek's host controller has two slots, each with it's own control
registers. The host driver need to identify which slot was connected
in order to access the device's configuration space. There's problem
for current host driver to find out which slot was connected to for
a given EP device.

Assuming each slot have connect with one EP device as below:

                host bridge
  bus 0 --> __________|_______
           |                  |
           |                  |
         slot 0             slot 1
  bus 1 -->|        bus 2 --> |
           |                  |
         EP 0               EP 1

During PCI enumeration, system software will scan all the PCI device
starting from devfn 0. So it will get the proper port for slot0 and
slot1 device when using PCI_SLOT(devfn) for match. But it will get
the wrong slot for EP1: The devfn will be start from 0 when scanning
EP1 behind slot1, it will get port0 since the PCI_SLOT(EP1) is match
for port0's slot value. So the host driver should not using EP's devfn
but the slot's devfn(the slot which EP was connected to) for match.

This patch fix the mtk_pcie_find_port's logic by using the slot's
devfn for match if finding device connected to the subordinate bus.

Signed-off-by: Honghui Zhang <honghui.zhang@mediatek.com>
---
 drivers/pci/controller/pcie-mediatek.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

Comments

Lorenzo Pieralisi Oct. 1, 2018, 2:36 p.m. UTC | #1 
On Fri, Sep 28, 2018 at 06:04:32PM +0800, honghui.zhang@mediatek.com wrote:
> From: Honghui Zhang <honghui.zhang@mediatek.com>
> 
> The Mediatek's host controller has two slots, each with it's own control
> registers. The host driver need to identify which slot was connected
> in order to access the device's configuration space. There's problem
> for current host driver to find out which slot was connected to for
> a given EP device.
> 
> Assuming each slot have connect with one EP device as below:
> 
>                 host bridge
>   bus 0 --> __________|_______
>            |                  |
>            |                  |
>          slot 0             slot 1
>   bus 1 -->|        bus 2 --> |
>            |                  |
>          EP 0               EP 1
> 
> During PCI enumeration, system software will scan all the PCI device
> starting from devfn 0. So it will get the proper port for slot0 and
> slot1 device when using PCI_SLOT(devfn) for match. But it will get
> the wrong slot for EP1: The devfn will be start from 0 when scanning
> EP1 behind slot1, it will get port0 since the PCI_SLOT(EP1) is match
> for port0's slot value. So the host driver should not using EP's devfn
> but the slot's devfn(the slot which EP was connected to) for match.
> 
> This patch fix the mtk_pcie_find_port's logic by using the slot's
> devfn for match if finding device connected to the subordinate bus.
> 
> Signed-off-by: Honghui Zhang <honghui.zhang@mediatek.com>
> ---
>  drivers/pci/controller/pcie-mediatek.c | 17 ++++++++++++++++-
>  1 file changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
> index 9999dae..264e03f 100644
> --- a/drivers/pci/controller/pcie-mediatek.c
> +++ b/drivers/pci/controller/pcie-mediatek.c
> @@ -337,10 +337,25 @@ static struct mtk_pcie_port *mtk_pcie_find_port(struct pci_bus *bus,
>  {
>  	struct mtk_pcie *pcie = bus->sysdata;
>  	struct mtk_pcie_port *port;
> +	struct pci_dev *dev = NULL;
> +
> +	/*
> +	 * Walk the bus hierarchy to get the devfn value
> +	 * of the port in the root bus.
> +	 */
> +	while (bus && bus->number) {
> +		dev = bus->self;
> +		bus = dev->bus;

If you add:

devfn = dev->devfn;

here

> +	}
> +
> +	list_for_each_entry(port, &pcie->ports, list) {
> +		/* Using slot's devfn to compare for subordinary bus. */
> +		if (dev)
> +			devfn = dev->devfn;

You can remove this ugly hunk altogether (and dev initialization
to NULL).

Lorenzo

> -	list_for_each_entry(port, &pcie->ports, list)
>  		if (port->slot == PCI_SLOT(devfn))
>  			return port;
> +	}
>  
>  	return NULL;
>  }
> -- 
> 2.6.4
>
Lorenzo Pieralisi Oct. 2, 2018, 10:59 a.m. UTC | #2 
On Mon, Oct 01, 2018 at 03:36:41PM +0100, Lorenzo Pieralisi wrote:
> On Fri, Sep 28, 2018 at 06:04:32PM +0800, honghui.zhang@mediatek.com wrote:
> > From: Honghui Zhang <honghui.zhang@mediatek.com>
> > 
> > The Mediatek's host controller has two slots, each with it's own control
> > registers. The host driver need to identify which slot was connected
> > in order to access the device's configuration space. There's problem
> > for current host driver to find out which slot was connected to for
> > a given EP device.
> > 
> > Assuming each slot have connect with one EP device as below:
> > 
> >                 host bridge
> >   bus 0 --> __________|_______
> >            |                  |
> >            |                  |
> >          slot 0             slot 1
> >   bus 1 -->|        bus 2 --> |
> >            |                  |
> >          EP 0               EP 1
> > 
> > During PCI enumeration, system software will scan all the PCI device
> > starting from devfn 0. So it will get the proper port for slot0 and
> > slot1 device when using PCI_SLOT(devfn) for match. But it will get
> > the wrong slot for EP1: The devfn will be start from 0 when scanning
> > EP1 behind slot1, it will get port0 since the PCI_SLOT(EP1) is match
> > for port0's slot value. So the host driver should not using EP's devfn
> > but the slot's devfn(the slot which EP was connected to) for match.
> > 
> > This patch fix the mtk_pcie_find_port's logic by using the slot's
> > devfn for match if finding device connected to the subordinate bus.
> > 
> > Signed-off-by: Honghui Zhang <honghui.zhang@mediatek.com>
> > ---
> >  drivers/pci/controller/pcie-mediatek.c | 17 ++++++++++++++++-
> >  1 file changed, 16 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
> > index 9999dae..264e03f 100644
> > --- a/drivers/pci/controller/pcie-mediatek.c
> > +++ b/drivers/pci/controller/pcie-mediatek.c
> > @@ -337,10 +337,25 @@ static struct mtk_pcie_port *mtk_pcie_find_port(struct pci_bus *bus,
> >  {
> >  	struct mtk_pcie *pcie = bus->sysdata;
> >  	struct mtk_pcie_port *port;
> > +	struct pci_dev *dev = NULL;
> > +
> > +	/*
> > +	 * Walk the bus hierarchy to get the devfn value
> > +	 * of the port in the root bus.
> > +	 */
> > +	while (bus && bus->number) {
> > +		dev = bus->self;
> > +		bus = dev->bus;
> 
> If you add:
> 
> devfn = dev->devfn;
> 
> here
> 
> > +	}
> > +
> > +	list_for_each_entry(port, &pcie->ports, list) {
> > +		/* Using slot's devfn to compare for subordinary bus. */
> > +		if (dev)
> > +			devfn = dev->devfn;
> 
> You can remove this ugly hunk altogether (and dev initialization
> to NULL).

Hi Honghui,

if you can make this change I would merge this series, it has been
been in the mailing lists for a while, I can make that change too
just let me know please.

Thanks,
Lorenzo
Honghui Zhang Oct. 8, 2018, 3:02 a.m. UTC | #3 
On Tue, 2018-10-02 at 11:59 +0100, Lorenzo Pieralisi wrote:
> On Mon, Oct 01, 2018 at 03:36:41PM +0100, Lorenzo Pieralisi wrote:
> > On Fri, Sep 28, 2018 at 06:04:32PM +0800, honghui.zhang@mediatek.com wrote:
> > > From: Honghui Zhang <honghui.zhang@mediatek.com>
> > > 
> > > The Mediatek's host controller has two slots, each with it's own control
> > > registers. The host driver need to identify which slot was connected
> > > in order to access the device's configuration space. There's problem
> > > for current host driver to find out which slot was connected to for
> > > a given EP device.
> > > 
> > > Assuming each slot have connect with one EP device as below:
> > > 
> > >                 host bridge
> > >   bus 0 --> __________|_______
> > >            |                  |
> > >            |                  |
> > >          slot 0             slot 1
> > >   bus 1 -->|        bus 2 --> |
> > >            |                  |
> > >          EP 0               EP 1
> > > 
> > > During PCI enumeration, system software will scan all the PCI device
> > > starting from devfn 0. So it will get the proper port for slot0 and
> > > slot1 device when using PCI_SLOT(devfn) for match. But it will get
> > > the wrong slot for EP1: The devfn will be start from 0 when scanning
> > > EP1 behind slot1, it will get port0 since the PCI_SLOT(EP1) is match
> > > for port0's slot value. So the host driver should not using EP's devfn
> > > but the slot's devfn(the slot which EP was connected to) for match.
> > > 
> > > This patch fix the mtk_pcie_find_port's logic by using the slot's
> > > devfn for match if finding device connected to the subordinate bus.
> > > 
> > > Signed-off-by: Honghui Zhang <honghui.zhang@mediatek.com>
> > > ---
> > >  drivers/pci/controller/pcie-mediatek.c | 17 ++++++++++++++++-
> > >  1 file changed, 16 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
> > > index 9999dae..264e03f 100644
> > > --- a/drivers/pci/controller/pcie-mediatek.c
> > > +++ b/drivers/pci/controller/pcie-mediatek.c
> > > @@ -337,10 +337,25 @@ static struct mtk_pcie_port *mtk_pcie_find_port(struct pci_bus *bus,
> > >  {
> > >  	struct mtk_pcie *pcie = bus->sysdata;
> > >  	struct mtk_pcie_port *port;
> > > +	struct pci_dev *dev = NULL;
> > > +
> > > +	/*
> > > +	 * Walk the bus hierarchy to get the devfn value
> > > +	 * of the port in the root bus.
> > > +	 */
> > > +	while (bus && bus->number) {
> > > +		dev = bus->self;
> > > +		bus = dev->bus;
> > 
> > If you add:
> > 
> > devfn = dev->devfn;
> > 
> > here
> > 
> > > +	}
> > > +
> > > +	list_for_each_entry(port, &pcie->ports, list) {
> > > +		/* Using slot's devfn to compare for subordinary bus. */
> > > +		if (dev)
> > > +			devfn = dev->devfn;
> > 
> > You can remove this ugly hunk altogether (and dev initialization
> > to NULL).
> 
> Hi Honghui,
> 
> if you can make this change I would merge this series, it has been
> been in the mailing lists for a while, I can make that change too
> just let me know please.
> 

Hi, Lorenzo, sorry for the late reply.

I tried your advise and it works fine.

I will send another version to fix this, as well as to add a fix tag in
the commit message of patch 6.

thanks

> Thanks,
> Lorenzo
diff mbox series

Patch

diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
index 9999dae..264e03f 100644
--- a/drivers/pci/controller/pcie-mediatek.c
+++ b/drivers/pci/controller/pcie-mediatek.c
@@ -337,10 +337,25 @@  static struct mtk_pcie_port *mtk_pcie_find_port(struct pci_bus *bus,
 {
 	struct mtk_pcie *pcie = bus->sysdata;
 	struct mtk_pcie_port *port;
+	struct pci_dev *dev = NULL;
+
+	/*
+	 * Walk the bus hierarchy to get the devfn value
+	 * of the port in the root bus.
+	 */
+	while (bus && bus->number) {
+		dev = bus->self;
+		bus = dev->bus;
+	}
+
+	list_for_each_entry(port, &pcie->ports, list) {
+		/* Using slot's devfn to compare for subordinary bus. */
+		if (dev)
+			devfn = dev->devfn;
 
-	list_for_each_entry(port, &pcie->ports, list)
 		if (port->slot == PCI_SLOT(devfn))
 			return port;
+	}
 
 	return NULL;
 }