On 19/06/2020 15:06, Leonardo Bras wrote:
> Platforms supporting the DDW option starting with LoPAR level 2.7 implement
> ibm,ddw-extensions. The first extension available (index 2) carries the
> token for ibm,reset-pe-dma-windows rtas call, which is used to restore
> the default DMA window for a device, if it has been deleted.
>
> It does so by resetting the TCE table allocation for the PE to it's
> boot time value, available in "ibm,dma-window" device tree node.
>
> Signed-off-by: Leonardo Bras <leobra...@gmail.com>
> ---
> arch/powerpc/platforms/pseries/iommu.c | 33 ++++++++++++++++++++++++++
> 1 file changed, 33 insertions(+)
>
> diff --git a/arch/powerpc/platforms/pseries/iommu.c
> b/arch/powerpc/platforms/pseries/iommu.c
> index e5a617738c8b..5e1fbc176a37 100644
> --- a/arch/powerpc/platforms/pseries/iommu.c
> +++ b/arch/powerpc/platforms/pseries/iommu.c
> @@ -1012,6 +1012,39 @@ static phys_addr_t ddw_memory_hotplug_max(void)
> return max_addr;
> }
>
> +/*
> + * Platforms supporting the DDW option starting with LoPAR level 2.7
> implement
> + * ibm,ddw-extensions, which carries the rtas token for
> + * ibm,reset-pe-dma-windows.
> + * That rtas-call can be used to restore the default DMA window for the
> device.
> + */
> +static void reset_dma_window(struct pci_dev *dev, struct device_node *par_dn)
> +{
> + int ret;
> + u32 cfg_addr, ddw_ext[3];
> + u64 buid;
> + struct device_node *dn;
> + struct pci_dn *pdn;
> +
> + ret = of_property_read_u32_array(par_dn, "ibm,ddw-extensions",
> + &ddw_ext[0], 3);
s/3/2/ as for the reset extension you do not need the "64bit largest
block" extension.
> + if (ret)
> + return;
> +
> + dn = pci_device_to_OF_node(dev);
> + pdn = PCI_DN(dn);
> + buid = pdn->phb->buid;
> + cfg_addr = ((pdn->busno << 16) | (pdn->devfn << 8));
> +
> + ret = rtas_call(ddw_ext[1], 3, 1, NULL, cfg_addr,
Here the "reset" extention is in ddw_ext[1]. Hm. 1/4 has a bug then.
And I am pretty sure it won't compile as reset_dma_window() is not used
and it is static so fold it into one the next patches. Thanks,
> + BUID_HI(buid), BUID_LO(buid));
> + if (ret)
> + dev_info(&dev->dev,
> + "ibm,reset-pe-dma-windows(%x) %x %x %x returned %d ",
> + ddw_ext[1], cfg_addr, BUID_HI(buid), BUID_LO(buid),
> + ret);
> +}
> +
> /*
> * If the PE supports dynamic dma windows, and there is space for a table
> * that can map all pages in a linear offset, then setup such a table,
>
--
Alexey
