Subject: Re: [PATCH v7 14/50] powerpc/powernv: M64 support on P7IOC

From: Alexey Kardashevskiy <[email-masked]>
Date: Mon, 16 Nov 2015 19:01:46 +1100

On 11/05/2015 12:12 AM, Gavin Shan wrote:
> This enables M64 window on P7IOC, which has been enabled on PHB3.
> Different from PHB3 where 16 M64 BARs are supported and each of
> them can be owned by one particular PE# exclusively or divided
> evenly to 256 segments, every P7IOC PHB has 16 M64 BARs and each
> of them are divided to 8 segments. So every P7IOC PHB supports
> 128 M64 segments in total. P7IOC has M64DT, which helps mapping
> one particular M64 segment# to arbitrary PE#. PHB3 doesn't have
> M64DT, indicating that one M64 segment can only be pinned to the
> fixed PE#. In order to have same code to support M64 on P7IOC and
> PHB3, we just provide 128 M64 segments on every P7IOC PHB and each
> of them is pinned to the fixed PE# by bypassing the function of
> M64DT. In turn, we just need different phb->init_m64() for P7IOC
> and PHB3 to support M64.
>
> Signed-off-by: Gavin Shan <[email-masked]>
> ---
>   arch/powerpc/platforms/powernv/pci-ioda.c | 86 +++++++++++++++++++++++++++++--
>   arch/powerpc/platforms/powernv/pci.h      |  3 ++
>   2 files changed, 86 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
> index 1f7d985..bfe69f1 100644
> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
> @@ -256,6 +256,64 @@ static void pnv_ioda_reserve_dev_m64_pe(struct pci_dev *pdev,
>   	}
>   }
>
> +static int pnv_ioda1_init_m64(struct pnv_phb *phb)
> +{
> +	struct resource *r;
> +	int index;
> +
> +	/*
> +	 * There are 16 M64 BARs, each of which has 8 segments. So
> +	 * there are as many M64 segments as the maximum number of
> +	 * PEs, which is 128.
> +	 */
> +	for (index = 0; index < PNV_IODA1_M64_NUM; index++) {
> +		unsigned long base, segsz = phb->ioda.m64_segsize;
> +		int64_t rc;
> +
> +		base = phb->ioda.m64_base +
> +		       index * PNV_IODA1_M64_SEGS * segsz;
> +		rc = opal_pci_set_phb_mem_window(phb->opal_id,
> +				OPAL_M64_WINDOW_TYPE, index, base, 0,
> +				PNV_IODA1_M64_SEGS * segsz);
> +		if (rc != OPAL_SUCCESS) {
> +			pr_warn("  Error %lld setting M64 PHB#%d-BAR#%d\n",
> +				rc, phb->hose->global_number, index);
> +			goto fail;
> +		}
> +
> +		rc = opal_pci_phb_mmio_enable(phb->opal_id,
> +				OPAL_M64_WINDOW_TYPE, index,
> +				OPAL_ENABLE_M64_SPLIT);
> +		if (rc != OPAL_SUCCESS) {
> +			pr_warn("  Error %lld enabling M64 PHB#%d-BAR#%d\n",
> +				rc, phb->hose->global_number, index);
> +			goto fail;
> +		}
> +	}
> +
> +	/*
> +	 * Exclude the segment used by the reserved PE, which
> +	 * is expected to be 0 or last supported PE#.
> +	 */
> +	r = &phb->hose->mem_resources[1];
> +	if (phb->ioda.reserved_pe_idx == 0)
> +		r->start += phb->ioda.m64_segsize;
> +	else if (phb->ioda.reserved_pe_idx == (phb->ioda.total_pe_num - 1))
> +		r->end -= phb->ioda.m64_segsize;
> +	else
> +		pr_warn("  Cannot cut M64 segment for reserved PE#%d\n",
> +			phb->ioda.reserved_pe_idx);
> +
> +	return 0;
> +
> +fail:
> +	for ( ; index >= 0; index--)
> +		opal_pci_phb_mmio_enable(phb->opal_id,
> +			OPAL_M64_WINDOW_TYPE, index, OPAL_DISABLE_M64);
> +
> +	return -EIO;
> +}
> +
>   static void pnv_ioda_reserve_m64_pe(struct pci_bus *bus,
>   				    unsigned long *pe_bitmap,
>   				    bool all)
> @@ -325,6 +383,26 @@ static int pnv_ioda_pick_m64_pe(struct pci_bus *bus, bool all)
>   			pe->master = master_pe;
>   			list_add_tail(&pe->list, &master_pe->slaves);
>   		}
> +
> +		/*
> +		 * P7IOC supports M64DT, which helps mapping M64 segment
> +		 * to one particular PE#. However, PHB3 has fixed mapping
> +		 * between M64 segment and PE#. In order to have same logic
> +		 * for P7IOC and PHB3, we enforce fixed mapping between M64
> +		 * segment and PE# on P7IOC.
> +		 */
> +		if (phb->type == PNV_PHB_IODA1) {
> +			int64_t rc;
> +
> +			rc = opal_pci_map_pe_mmio_window(phb->opal_id,
> +					pe->pe_number, OPAL_M64_WINDOW_TYPE,
> +					pe->pe_number / PNV_IODA1_M64_SEGS,
> +					pe->pe_number % PNV_IODA1_M64_SEGS);
> +			if (rc != OPAL_SUCCESS)
> +				pr_warn("%s: Error %lld mapping M64 for PHB#%d-PE#%d\n",
> +					__func__, rc, phb->hose->global_number,
> +					pe->pe_number);
> +		}
>   	}
>
>   	kfree(pe_alloc);
> @@ -339,8 +417,7 @@ static void __init pnv_ioda_parse_m64_window(struct pnv_phb *phb)
>   	const u32 *r;
>   	u64 pci_addr;
>
> -	/* FIXME: Support M64 for P7IOC */
> -	if (phb->type != PNV_PHB_IODA2) {
> +	if (phb->type != PNV_PHB_IODA1 && phb->type != PNV_PHB_IODA2) {
>   		pr_info("  Not support M64 window\n");
>   		return;
>   	}
> @@ -373,7 +450,10 @@ static void __init pnv_ioda_parse_m64_window(struct pnv_phb *phb)
>
>   	/* Use last M64 BAR to cover M64 window */
>   	phb->ioda.m64_bar_idx = 15;
> -	phb->init_m64 = pnv_ioda2_init_m64;
> +	if (phb->type == PNV_PHB_IODA1)
> +		phb->init_m64 = pnv_ioda1_init_m64;
> +	else
> +		phb->init_m64 = pnv_ioda2_init_m64;
>   	phb->reserve_m64_pe = pnv_ioda_reserve_m64_pe;
>   	phb->pick_m64_pe = pnv_ioda_pick_m64_pe;

Nit: the callbacks initialization does not seem to relate to parsing any 
window :) They could all go to where pnv_ioda_parse_m64_window() is called, 
no separate patch is needed.

>   }
> diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
> index 671fd13..c4019ac 100644
> --- a/arch/powerpc/platforms/powernv/pci.h
> +++ b/arch/powerpc/platforms/powernv/pci.h
> @@ -78,6 +78,9 @@ struct pnv_ioda_pe {
>   	struct list_head	list;
>   };
>
> +#define PNV_IODA1_M64_NUM	16	/* Number of M64 BARs   */
> +#define PNV_IODA1_M64_SEGS	8	/* Segments per M64 BAR */
> +
>   #define PNV_PHB_FLAG_EEH	(1 << 0)
>
>   struct pnv_phb {
>

-- 
Alexey