Subject: Re: [PATCH v7 17/50] powerpc/powernv: Avoid calculating DMA32 segments on PHB3

From: Alexey Kardashevskiy <[email-masked]>
Date: Tue, 17 Nov 2015 12:07:17 +1100

On 11/05/2015 12:12 AM, Gavin Shan wrote:
> In pnv_ioda_setup_dma(), it's unnecessary to calculate the DMA32
> segments for PEs on PHB3 as the whole available DMA32 space can
> be assigned to one specific PE on PHB3.
>
> This splits pnv_ioda_setup_dma() to pnv_pci_ioda1_setup_dma() and
> pnv_pci_ioda2_setup_dma() in order to avoid calculating DMA32
> segments for PEs on PHB3. No logical changes introduced.

This patch is not needed as

[PATCH v7 20/50] powerpc/powernv: Improve DMA32 segment calculation

moves this calculation to another place (which already makes this patch 
unnecessary) and

[PATCH v7 26/50] powerpc/powernv: Create PEs at PCI hot plugging time

removes just introduced pnv_pci_ioda1_setup_dma() - if you remove it, then 
there is no point in fixing it in the first place.

>
> Signed-off-by: Gavin Shan <[email-masked]>
> ---
>   arch/powerpc/platforms/powernv/pci-ioda.c | 41 ++++++++++++++++++-------------
>   1 file changed, 24 insertions(+), 17 deletions(-)
>
> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
> index 5a08e20..4c2e023 100644
> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
> @@ -2383,7 +2383,7 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
>   		pnv_ioda_setup_bus_dma(pe, pe->pbus);
>   }
>
> -static void pnv_ioda_setup_dma(struct pnv_phb *phb)
> +static void pnv_pci_ioda1_setup_dma(struct pnv_phb *phb)
>   {
>   	struct pci_controller *hose = phb->hose;
>   	unsigned int residual, remaining, segs, tw, base;
> @@ -2428,26 +2428,30 @@ static void pnv_ioda_setup_dma(struct pnv_phb *phb)
>   				segs = remaining;
>   		}
>
> -		/*
> -		 * For IODA2 compliant PHB3, we needn't care about the weight.
> -		 * The all available 32-bits DMA space will be assigned to
> -		 * the specific PE.
> -		 */
> -		if (phb->type == PNV_PHB_IODA1) {
> -			pe_info(pe, "DMA weight %d, assigned %d DMA32 segments\n",
> -				pe->dma_weight, segs);
> -			pnv_pci_ioda1_setup_dma_pe(phb, pe, base, segs);
> -		} else {
> -			pe_info(pe, "Assign DMA32 space\n");
> -			segs = 0;
> -			pnv_pci_ioda2_setup_dma_pe(phb, pe);
> -		}
> +		pe_info(pe, "DMA weight %d, assigned %d DMA32 segments\n",
> +			pe->dma_weight, segs);
> +		pnv_pci_ioda1_setup_dma_pe(phb, pe, base, segs);
>
>   		remaining -= segs;
>   		base += segs;
>   	}
>   }
>
> +static void pnv_pci_ioda2_setup_dma(struct pnv_phb *phb)
> +{
> +	struct pnv_ioda_pe *pe;
> +
> +	pnv_pci_ioda_setup_opal_tce_kill(phb);
> +
> +	list_for_each_entry(pe, &phb->ioda.pe_dma_list, dma_link) {
> +		if (!pe->dma_weight)
> +			continue;
> +
> +		pe_info(pe, "Assign DMA32 space\n");
> +		pnv_pci_ioda2_setup_dma_pe(phb, pe);
> +	}
> +}
> +
>   #ifdef CONFIG_PCI_MSI
>   static void pnv_ioda2_msi_eoi(struct irq_data *d)
>   {
> @@ -2931,10 +2935,13 @@ static void pnv_pci_ioda_setup_DMA(void)
>   	struct pnv_phb *phb;
>
>   	list_for_each_entry_safe(hose, tmp, &hose_list, list_node) {
> -		pnv_ioda_setup_dma(hose->private_data);
> +		phb = hose->private_data;
> +		if (phb->type == PNV_PHB_IODA1)
> +			pnv_pci_ioda1_setup_dma(phb);
> +		else
> +			pnv_pci_ioda2_setup_dma(phb);
>
>   		/* Mark the PHB initialization done */
> -		phb = hose->private_data;
>   		phb->initialized = 1;
>   	}
>   }
>

-- 
Alexey