[PATCH 6/6] i.MX6: pci: Avoid aborts when asserting PCIe reset

[Sascha Hauer]

The PCI patches look good to me. I'll give Lucas the change to look over
them.

Sascha

On Thu, Dec 31, 2015 at 09:58:38PM -0800, Andrey Smirnov wrote:
> When booting Barebox in the HW environment where PCIe core has been
> used but not properly shut down, writing to PCIE_PL_PFLR in
> imx6_pcie_assert_core_reset would cause data abort exception.
> 
> The problem can be easily reproduced on a i.MX6 based board with PCIe
> slot populated with some device by doing:
> 
> > bootm -f -e 0x1050 <your board's>.img
> 
> Ignoring this exception seem to allow PCIe core to successfully
> initialize and enumerate devices properly. This is also how Linux
> Kernel version of the driver handles this situation -- it installs
> dummy no-op abort handler at the beginning of device's probing.
> 
> Signed-off-by: Andrey Smirnov <andrew.smirnov at gmail.com>
> ---
>  drivers/pci/pci-imx6.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/pci/pci-imx6.c b/drivers/pci/pci-imx6.c
> index 713007b..3a3edd8 100644
> --- a/drivers/pci/pci-imx6.c
> +++ b/drivers/pci/pci-imx6.c
> @@ -13,6 +13,7 @@
> 
>  #include <common.h>
>  #include <clock.h>
> +#include <abort.h>
>  #include <malloc.h>
>  #include <io.h>
>  #include <init.h>
> @@ -237,7 +238,10 @@ static int imx6_pcie_assert_core_reset(struct pcie_port *pp)
>  		val = readl(pp->dbi_base + PCIE_PL_PFLR);
>  		val &= ~PCIE_PL_PFLR_LINK_STATE_MASK;
>  		val |= PCIE_PL_PFLR_FORCE_LINK;
> +
> +		data_abort_mask();
>  		writel(val, pp->dbi_base + PCIE_PL_PFLR);
> +		data_abort_unmask();
> 
>  		gpr12 &= ~IMX6Q_GPR12_PCIE_CTL_2;
>  		writel(gpr12, imx6_pcie->iomuxc_gpr + IOMUXC_GPR12);
> --
> 2.5.0
> 
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> 

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