Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1256412

Re: [RFC PATCH 1/3] PCI: iproc: generate proper configuration access cycles

Show all headers | View raw

On Mon, 26 Oct 2015 10:18:14 -0700
Ray Jui <rjui@broadcom.com> wrote:

> Hi Jisheng,
> 
> On 10/26/2015 4:02 AM, Jisheng Zhang wrote:
> > Inspired by Russell King's patch[1], I found current iproc also has the
> > same issue of "reading 32-bits from the command register, modifying the
> > command register, and then writing it back has the effect of clearing
> > any status bits that were indicating at that time" as pointed out by
> > Russell. This patch fix this issue by using the pci_generic_config_write.
> >
> > [1]http://www.spinics.net/lists/linux-pci/msg44869.html
> >
> > Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
> > ---
> >   drivers/pci/host/pcie-iproc.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/pci/host/pcie-iproc.c b/drivers/pci/host/pcie-iproc.c
> > index fe2efb1..0c423f2 100644
> > --- a/drivers/pci/host/pcie-iproc.c
> > +++ b/drivers/pci/host/pcie-iproc.c
> > @@ -111,7 +111,7 @@ static void __iomem *iproc_pcie_map_cfg_bus(struct pci_bus *bus,
> >   static struct pci_ops iproc_pcie_ops = {
> >   	.map_bus = iproc_pcie_map_cfg_bus,
> >   	.read = pci_generic_config_read32,
> > -	.write = pci_generic_config_write32,
> > +	.write = pci_generic_config_write,
> >   };
> >
> >   static void iproc_pcie_reset(struct iproc_pcie *pcie)
> >  
> 
> I have already confirmed with the ASIC team that the current iProc PCIe 
> controller requires 32-bit aligned access into the configuration space 
> due to the way how it was integrated into various iProc SoCs including 
> NSP, Cygnus, and NS2.
> 
> This change will prevent the driver from working properly.
> 
> I've informed our ASIC team about this issue and all future iProc based 
> SoCs should be able to support 8-bit, 16-bit access and therefore 
> pci_generic_config_write/read can be used for those SoCs.
> 
> Thanks,
> 
> Ray

Got it. 

Thanks for the information,
Jisheng
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[RFC PATCH 1/3] PCI: iproc: generate proper configuration access cycles Jisheng Zhang <jszhang@marvell.com> - 2015-10-26 12:10 +0100
  Re: [RFC PATCH 1/3] PCI: iproc: generate proper configuration access  cycles Ray Jui <rjui@broadcom.com> - 2015-10-26 18:20 +0100
    Re: [RFC PATCH 1/3] PCI: iproc: generate proper configuration  access cycles Jisheng Zhang <jszhang@marvell.com> - 2015-10-27 03:30 +0100
      Re: [RFC PATCH 1/3] PCI: iproc: generate proper configuration access cycles Arnd Bergmann <arnd@arndb.de> - 2015-10-31 00:30 +0100

csiph-web