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Date: Mon, 15 Apr 2024 10:34:26 +0200
From: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
To: Songyang Li <leesongyang@outlook.com>
Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] MIPS: Octeon: Add PCIe link status check
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On Wed, Mar 20, 2024 at 11:22:00PM +0800, Songyang Li wrote:
> The standard PCIe configuration read-write interface is used to
> access the configuration space of the peripheral PCIe devices
> of the mips processor after the PCIe link surprise down, it can
> generate kernel panic caused by "Data bus error". So it is
> necessary to add PCIe link status check for system protection.
> When the PCIe link is down or in training, assigning a value
> of 0 to the configuration address can prevent read-write behavior
> to the configuration space of peripheral PCIe devices, thereby
> preventing kernel panic.
> 
> Signed-off-by: Songyang Li <leesongyang@outlook.com>
> ---
>  arch/mips/pci/pcie-octeon.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>  mode change 100644 => 100755 arch/mips/pci/pcie-octeon.c
> 
> diff --git a/arch/mips/pci/pcie-octeon.c b/arch/mips/pci/pcie-octeon.c
> old mode 100644
> new mode 100755
> index 2583e318e8c6..b080c7c6cc46
> --- a/arch/mips/pci/pcie-octeon.c
> +++ b/arch/mips/pci/pcie-octeon.c
> @@ -230,12 +230,18 @@ static inline uint64_t __cvmx_pcie_build_config_addr(int pcie_port, int bus,
>  {
>  	union cvmx_pcie_address pcie_addr;
>  	union cvmx_pciercx_cfg006 pciercx_cfg006;
> +	union cvmx_pciercx_cfg032 pciercx_cfg032;
>  
>  	pciercx_cfg006.u32 =
>  	    cvmx_pcie_cfgx_read(pcie_port, CVMX_PCIERCX_CFG006(pcie_port));
>  	if ((bus <= pciercx_cfg006.s.pbnum) && (dev != 0))
>  		return 0;
>  
> +	pciercx_cfg032.u32 =
> +		cvmx_pcie_cfgx_read(pcie_port, CVMX_PCIERCX_CFG032(pcie_port));
> +	if ((pciercx_cfg032.s.dlla == 0) || (pciercx_cfg032.s.lt == 1))
> +		return 0;
> +
>  	pcie_addr.u64 = 0;
>  	pcie_addr.config.upper = 2;
>  	pcie_addr.config.io = 1;
> -- 
> 2.34.1

applied to mips-next.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]