[PATCH 1/2] PCI: iproc: export iproc_pcie_shutdown symbol

[PATCH 1/2] PCI: iproc: export iproc_pcie_shutdown symbol

[Arnd Bergmann]

The shutdown bugfix introduce a build regression for allmodconfig
kernels as the new function is not exported:

ERROR: "iproc_pcie_shutdown" [drivers/pci/host/pcie-iproc-platform.ko] undefined!

This adds the missing export.

Fixes: 2a9912565c05 ("PCI: iproc: Add 500ms delay during device shutdown")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/pci/host/pcie-iproc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/pci/host/pcie-iproc.c b/drivers/pci/host/pcie-iproc.c
index 8bd5e544b1c1..d7f4c29aed96 100644
--- a/drivers/pci/host/pcie-iproc.c
+++ b/drivers/pci/host/pcie-iproc.c
@@ -704,6 +704,7 @@ int iproc_pcie_shutdown(struct iproc_pcie *pcie)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(iproc_pcie_shutdown);
 
 static int iproc_pcie_check_link(struct iproc_pcie *pcie)
 {
-- 
2.9.0

[PATCH 2/2] PCI: iproc: fix Stingray CRS defect handling

[Arnd Bergmann]

The condition that was used to detect the PCI_EXP_RTCAP
flag access is wrong, as pointed out by gcc-8:

drivers/pci/host/pcie-iproc.c: In function 'iproc_pcie_config_read':
drivers/pci/host/pcie-iproc.c:531:22: error: bitwise comparison always evaluates to false [-Werror=tautological-compare]
   if ((where & ~0x3) == PCI_EXP_CAP + PCI_EXP_RTCAP)

This adds the same bit mask to the other end as well, so the
condition is evaluated correctly for any access.

Fixes: ac8d3e852f75 ("PCI: iproc: Work around Stingray CRS defects")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 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 d7f4c29aed96..f2df9c2266b9 100644
--- a/drivers/pci/host/pcie-iproc.c
+++ b/drivers/pci/host/pcie-iproc.c
@@ -528,7 +528,7 @@ static int iproc_pcie_config_read(struct pci_bus *bus, unsigned int devfn,
 			return ret;
 
 		/* Don't advertise CRS SV support */
-		if ((where & ~0x3) == PCI_EXP_CAP + PCI_EXP_RTCAP)
+		if ((where & ~0x3) == ((PCI_EXP_CAP + PCI_EXP_RTCAP) & ~0x03))
 			*val &= ~(PCI_EXP_RTCAP_CRSVIS << 16);
 		return PCIBIOS_SUCCESSFUL;
 	}
-- 
2.9.0

Re: [PATCH 1/2] PCI: iproc: export iproc_pcie_shutdown symbol

[Bjorn Helgaas]

On Tue, Sep 05, 2017 at 09:19:44AM +0200, Arnd Bergmann wrote:
> The shutdown bugfix introduce a build regression for allmodconfig
> kernels as the new function is not exported:
> 
> ERROR: "iproc_pcie_shutdown" [drivers/pci/host/pcie-iproc-platform.ko] undefined!
> 
> This adds the missing export.
> 
> Fixes: 2a9912565c05 ("PCI: iproc: Add 500ms delay during device shutdown")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Folded into the 2a9912565c05 commit, thanks!

> ---
>  drivers/pci/host/pcie-iproc.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/pci/host/pcie-iproc.c b/drivers/pci/host/pcie-iproc.c
> index 8bd5e544b1c1..d7f4c29aed96 100644
> --- a/drivers/pci/host/pcie-iproc.c
> +++ b/drivers/pci/host/pcie-iproc.c
> @@ -704,6 +704,7 @@ int iproc_pcie_shutdown(struct iproc_pcie *pcie)
>  
>  	return 0;
>  }
> +EXPORT_SYMBOL_GPL(iproc_pcie_shutdown);
>  
>  static int iproc_pcie_check_link(struct iproc_pcie *pcie)
>  {
> -- 
> 2.9.0
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH 2/2] PCI: iproc: fix Stingray CRS defect handling

[Bjorn Helgaas]

On Tue, Sep 05, 2017 at 09:19:45AM +0200, Arnd Bergmann wrote:
> The condition that was used to detect the PCI_EXP_RTCAP
> flag access is wrong, as pointed out by gcc-8:
> 
> drivers/pci/host/pcie-iproc.c: In function 'iproc_pcie_config_read':
> drivers/pci/host/pcie-iproc.c:531:22: error: bitwise comparison always evaluates to false [-Werror=tautological-compare]
>    if ((where & ~0x3) == PCI_EXP_CAP + PCI_EXP_RTCAP)
> 
> This adds the same bit mask to the other end as well, so the
> condition is evaluated correctly for any access.
> 
> Fixes: ac8d3e852f75 ("PCI: iproc: Work around Stingray CRS defects")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  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 d7f4c29aed96..f2df9c2266b9 100644
> --- a/drivers/pci/host/pcie-iproc.c
> +++ b/drivers/pci/host/pcie-iproc.c
> @@ -528,7 +528,7 @@ static int iproc_pcie_config_read(struct pci_bus *bus, unsigned int devfn,
>  			return ret;
>  
>  		/* Don't advertise CRS SV support */
> -		if ((where & ~0x3) == PCI_EXP_CAP + PCI_EXP_RTCAP)
> +		if ((where & ~0x3) == ((PCI_EXP_CAP + PCI_EXP_RTCAP) & ~0x03))
>  			*val &= ~(PCI_EXP_RTCAP_CRSVIS << 16);
>  		return PCIBIOS_SUCCESSFUL;
>  	}

Definitely looks like a bug.  I'm slightly confused because Oza tested
this and reported that lspci said CRS SV was not supported.  But there
used to be an lspci bug related to reporting CRS SV, and there are a
lot of executables that don't have the fix:

http://git.kernel.org/cgit/utils/pciutils/pciutils.git/commit/?id=1cefd379194e

lspci -vvxxx should have enough info to tell for sure.  Oza, any
chance you could apply the incremental patch (or use my pci/host-iproc
branch) and collect that lspci output?

I propose the following slightly different fix because (a) the shift
in the next line depends on the fact that we read the 32-bit value
that contains both PCI_EXP_RTCTL and PCI_EXP_RTCAP so I like the use
of PCI_EXP_RTCTL as a hint that it's involved and (b) there's similar
code in xgene_pcie_config_read32() that uses the equivalent of
PCI_EXP_RTCTL; see

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/pci/host/pci-xgene.c?h=v4.13#n191

diff --git a/drivers/pci/host/pcie-iproc.c b/drivers/pci/host/pcie-iproc.c
index 0e29338703bf..9a006cbc3021 100644
--- a/drivers/pci/host/pcie-iproc.c
+++ b/drivers/pci/host/pcie-iproc.c
@@ -528,7 +528,7 @@ static int iproc_pcie_config_read(struct pci_bus *bus, unsigned int devfn,
 			return ret;
 
 		/* Don't advertise CRS SV support */
-		if ((where & ~0x3) == PCI_EXP_CAP + PCI_EXP_RTCAP)
+		if ((where & ~0x3) == PCI_EXP_CAP + PCI_EXP_RTCTL)
 			*val &= ~(PCI_EXP_RTCAP_CRSVIS << 16);
 		return PCIBIOS_SUCCESSFUL;
 	}