linux-kernel - Re: [PATCH kernel v8 18/31] powerpc/powernv/ioda2: Rework iommu

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Date:	Thu, 16 Apr 2015 16:29:11 +1000
From:	David Gibson <david@...son.dropbear.id.au>
To:	Alexey Kardashevskiy <aik@...abs.ru>
Cc:	linuxppc-dev@...ts.ozlabs.org,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Paul Mackerras <paulus@...ba.org>,
	Alex Williamson <alex.williamson@...hat.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH kernel v8 18/31] powerpc/powernv/ioda2: Rework
 iommu_table creation

On Fri, Apr 10, 2015 at 04:31:00PM +1000, Alexey Kardashevskiy wrote:
> This moves iommu_table creation to the beginning. This is a mechanical
> patch.
> 
> Signed-off-by: Alexey Kardashevskiy <aik@...abs.ru>
> ---
>  arch/powerpc/platforms/powernv/pci-ioda.c | 34 ++++++++++++++++---------------
>  1 file changed, 18 insertions(+), 16 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
> index 4d80502..a1e0df9 100644
> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
> @@ -1437,27 +1437,33 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
>  	addr = page_address(tce_mem);
>  	memset(addr, 0, tce_table_size);
>  
> +	/* Setup iommu */
> +	pe->table_group.tables[0].it_group = &pe->table_group;
> +
> +	/* Setup linux iommu table */
> +	tbl = &pe->table_group.tables[0];
> +	pnv_pci_setup_iommu_table(tbl, addr, tce_table_size, 0,
> +			IOMMU_PAGE_SHIFT_4K);
> +
> +	tbl->it_ops = &pnv_ioda2_iommu_ops;
> +	iommu_init_table(tbl, phb->hose->node);
> +#ifdef CONFIG_IOMMU_API
> +	pe->table_group.ops = &pnv_pci_ioda2_ops;
> +#endif
> +
>  	/*
>  	 * Map TCE table through TVT. The TVE index is the PE number
>  	 * shifted by 1 bit for 32-bits DMA space.
>  	 */
>  	rc = opal_pci_map_pe_dma_window(phb->opal_id, pe->pe_number,
> -					pe->pe_number << 1, 1, __pa(addr),
> -					tce_table_size, 0x1000);
> +			pe->pe_number << 1, 1, __pa(tbl->it_base),
> +			tbl->it_size << 3, 1ULL << tbl->it_page_shift);

This looks like a real change, not just mechanical code movement.

>  	if (rc) {
>  		pe_err(pe, "Failed to configure 32-bit TCE table,"
>  		       " err %ld\n", rc);
>  		goto fail;
>  	}
>  
> -	/* Setup iommu */
> -	pe->table_group.tables[0].it_group = &pe->table_group;
> -
> -	/* Setup linux iommu table */
> -	tbl = &pe->table_group.tables[0];
> -	pnv_pci_setup_iommu_table(tbl, addr, tce_table_size, 0,
> -			IOMMU_PAGE_SHIFT_4K);
> -
>  	/* OPAL variant of PHB3 invalidated TCEs */
>  	swinvp = of_get_property(phb->hose->dn, "ibm,opal-tce-kill", NULL);
>  	if (swinvp) {
> @@ -1471,16 +1477,12 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
>  				8);
>  		tbl->it_type |= (TCE_PCI_SWINV_CREATE | TCE_PCI_SWINV_FREE);
>  	}
> -	tbl->it_ops = &pnv_ioda2_iommu_ops;
> -	iommu_init_table(tbl, phb->hose->node);
> -#ifdef CONFIG_IOMMU_API
> -	pe->table_group.ops = &pnv_pci_ioda2_ops;
> -#endif
>  	iommu_register_group(&pe->table_group, phb->hose->global_number,
>  			pe->pe_number);
>  
>  	if (pe->pdev)
> -		set_iommu_table_base_and_group(&pe->pdev->dev, tbl);
> +		set_iommu_table_base_and_group(&pe->pdev->dev,
> +				&pe->table_group.tables[0]);

And it's not obvious why this change happens either.

>  	else
>  		pnv_ioda_setup_bus_dma(pe, pe->pbus, true);
>  

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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