Re: [PATCH v6 10/42] powerpc/powernv: pnv_ioda_setup_dma() configure one PE only

Alexey Kardashevskiy
2015-08-10T09:31:11Z

On 08/06/2015 02:11 PM, Gavin Shan wrote:
> The original implementation of pnv_ioda_setup_dma() iterates the
> list of PEs and configures the DMA32 space for them one by one.
> The function was designed to be called during PHB fixup time.
> When configuring PE's DMA32 space in pcibios_setup_bridge(), in
> order to support PCI hotplug, we have to have the function PE
> oriented.
>
> This renames pnv_ioda_setup_dma() to pnv_ioda1_setup_dma() and
> adds one more argument "struct pnv_ioda_pe *pe" to it. The caller,
> pnv_pci_ioda_setup_DMA(), gets PE from the list and passes to it
> or pnv_pci_ioda2_setup_dma_pe(). The patch shouldn't cause behavioral
> changes.
>
> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
> ---
> arch/powerpc/platforms/powernv/pci-ioda.c | 75 +++++++++++++++----------------
> 1 file changed, 36 insertions(+), 39 deletions(-)
>
> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
> index 8456f37..cd22002 100644
> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
> @@ -2443,52 +2443,29 @@ 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 unsigned int pnv_ioda1_setup_dma(struct pnv_phb *phb,
> + struct pnv_ioda_pe *pe,
> + unsigned int base)
> {
> struct pci_controller *hose = phb->hose;
> - struct pnv_ioda_pe *pe;
> - unsigned int dma_weight;
> + unsigned int dma_weight, segs;
>
> /* Calculate the PHB's DMA weight */
> dma_weight = pnv_ioda_phb_dma_weight(phb);
> pr_info("PCI%04x has %ld DMA32 segments, total weight %d\n",
> hose->global_number, phb->ioda.dma32_segcount, dma_weight);
>
> - pnv_pci_ioda_setup_opal_tce_kill(phb);
> -
> - /* Walk our PE list and configure their DMA segments, hand them
> - * out one base segment plus any residual segments based on
> - * weight
> - */
> - list_for_each_entry(pe, &phb->ioda.pe_dma_list, dma_link) {
> - if (!pe->dma32_weight)
> - continue;
> -
> - /*
> - * 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) {
> - unsigned int segs, base = 0;
> -
> - if (pe->dma32_weight <
> - dma_weight / phb->ioda.dma32_segcount)
> - segs = 1;
> - else
> - segs = (pe->dma32_weight *
> - phb->ioda.dma32_segcount) / dma_weight;
> -
> - pe_info(pe, "DMA32 weight %d, assigned %d segments\n",
> - pe->dma32_weight, segs);
> - pnv_pci_ioda_setup_dma_pe(phb, pe, base, segs);
> + if (pe->dma32_weight <
> + dma_weight / phb->ioda.dma32_segcount)

Can be one line now.

> + segs = 1;
> + else
> + segs = (pe->dma32_weight *
> + phb->ioda.dma32_segcount) / dma_weight;
> + pe_info(pe, "DMA weight %d, assigned %d segments\n",
> + pe->dma32_weight, segs);
> + pnv_pci_ioda_setup_dma_pe(phb, pe, base, segs);

Why not to merge pnv_ioda1_setup_dma() to pnv_pci_ioda_setup_dma_pe()?

>
> - base += segs;
> - } else {
> - pe_info(pe, "Assign DMA32 space\n");
> - pnv_pci_ioda2_setup_dma_pe(phb, pe);
> - }
> - }
> + return segs;
> }
>
> #ifdef CONFIG_PCI_MSI
> @@ -2955,12 +2932,32 @@ static void pnv_pci_ioda_setup_DMA(void)
> {
> struct pci_controller *hose, *tmp;
> struct pnv_phb *phb;
> + struct pnv_ioda_pe *pe;
> + unsigned int base;
>
> list_for_each_entry_safe(hose, tmp, &hose_list, list_node) {
> - pnv_ioda_setup_dma(hose->private_data);
> + phb = hose->private_data;
> + pnv_pci_ioda_setup_opal_tce_kill(phb);
> +
> + base = 0;
> + list_for_each_entry(pe, &phb->ioda.pe_dma_list, dma_link) {
> + if (!pe->dma32_weight)
> + continue;
> +
> + switch (phb->type) {
> + case PNV_PHB_IODA1:
> + base += pnv_ioda1_setup_dma(phb, pe, base);

This @base handling seems never be tested between 8..11 as "[PATCH v6
11/42] powerpc/powernv: Trace DMA32 segments consumed by PE"
removes it and I suspect you only tested the final version. Which is ok for
the final result but not ok for bisectability.

Looks like 8/42, 9/42, 10/42, 11/42 need to be rearranged or merged to
remove this multiple @base touching.

> + break;
> + case PNV_PHB_IODA2:
> + pnv_pci_ioda2_setup_dma_pe(phb, pe);
> + break;
> + default:
> + pr_warn("%s: No DMA for PHB type %d\n",
> + __func__, phb->type);
> + }
> + }
>
> /* Mark the PHB initialization done */
> - phb = hose->private_data;
> phb->initialized = 1;
> }
> }
>

--
Alexey