Subject: Re: [PATCH v5 08/42] powerpc/powernv: DMA32 cleanup

From: Alexey Kardashevskiy <[email-masked]>
Date: Wed, 10 Jun 2015 14:17:26 +1000

On 06/04/2015 04:41 PM, Gavin Shan wrote:
> The patch cleans up DMA32 in pci-ioda.c. It shouldn't introduce
> behavioural changes:
>
>     * Rename various fields in "struct pnv_phb" and "struct pnv_ioda_pe"
>       as 32-bits DMA should be related to "DMA", not "TCE", and move
>       them around to reflect their relationship and their relative
>       importance.
>     * Removed struct pnv_ioda_pe::tce32_segcount.
>
> Signed-off-by: Gavin Shan <[email-masked]>
> ---
> v5:
>    * Split from PATCH[v4 5/21]
> ---
>   arch/powerpc/platforms/powernv/pci-ioda.c | 48 +++++++++++++++----------------
>   arch/powerpc/platforms/powernv/pci.h      | 13 +++------
>   2 files changed, 28 insertions(+), 33 deletions(-)
>
> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
> index d9ff739..4af3d06 100644
> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
> @@ -971,7 +971,7 @@ static void pnv_ioda_link_pe_by_weight(struct pnv_phb *phb,
>   	struct pnv_ioda_pe *lpe;
>
>   	list_for_each_entry(lpe, &phb->ioda.pe_dma_list, dma_link) {
> -		if (lpe->dma_weight < pe->dma_weight) {
> +		if (lpe->dma32_weight < pe->dma32_weight) {
>   			list_add_tail(&pe->dma_link, &lpe->dma_link);
>   			return;
>   		}
> @@ -996,14 +996,14 @@ static unsigned int pnv_ioda_dev_dma_weight(struct pci_dev *dev)
>   	if (dev->class == PCI_CLASS_SERIAL_USB_UHCI ||
>   	    dev->class == PCI_CLASS_SERIAL_USB_OHCI ||
>   	    dev->class == PCI_CLASS_SERIAL_USB_EHCI)
> -		return 3 * phb->ioda.tce32_count;
> +		return 3 * phb->ioda.dma32_segcount;
>
>   	/* Increase the weight of RAID (includes Obsidian) */
>   	if ((dev->class >> 8) == PCI_CLASS_STORAGE_RAID)
> -		return 15 * phb->ioda.tce32_count;
> +		return 15 * phb->ioda.dma32_segcount;
>
>   	/* Default */
> -	return 10 * phb->ioda.tce32_count;
> +	return 10 * phb->ioda.dma32_segcount;
>   }
>
>   static int __pnv_ioda_phb_dma_weight(struct pci_dev *pdev, void *data)
> @@ -1182,7 +1182,7 @@ static void pnv_ioda_setup_same_PE(struct pci_bus *bus, struct pnv_ioda_pe *pe)
>   			continue;
>   		}
>   		pdn->pe_number = pe->pe_number;
> -		pe->dma_weight += pnv_ioda_dev_dma_weight(dev);
> +		pe->dma32_weight += pnv_ioda_dev_dma_weight(dev);
>   		if ((pe->flags & PNV_IODA_PE_BUS_ALL) && dev->subordinate)
>   			pnv_ioda_setup_same_PE(dev->subordinate, pe);
>   	}
> @@ -1219,10 +1219,10 @@ static void pnv_ioda_setup_bus_PE(struct pci_bus *bus, int all)
>   	pe->flags |= (all ? PNV_IODA_PE_BUS_ALL : PNV_IODA_PE_BUS);
>   	pe->pbus = bus;
>   	pe->pdev = NULL;
> -	pe->tce32_seg = -1;
> +	pe->dma32_seg = -1;
>   	pe->mve_number = -1;
>   	pe->rid = bus->busn_res.start << 8;
> -	pe->dma_weight = 0;
> +	pe->dma32_weight = 0;
>
>   	if (all)
>   		pe_info(pe, "Secondary bus %d..%d associated with PE#%d\n",
> @@ -1585,7 +1585,7 @@ static void pnv_ioda_setup_vf_PE(struct pci_dev *pdev, u16 num_vfs)
>   		pe->flags = PNV_IODA_PE_VF;
>   		pe->pbus = NULL;
>   		pe->parent_dev = pdev;
> -		pe->tce32_seg = -1;
> +		pe->dma32_seg = -1;
>   		pe->mve_number = -1;
>   		pe->rid = (pci_iov_virtfn_bus(pdev, vf_index) << 8) |
>   			   pci_iov_virtfn_devfn(pdev, vf_index);
> @@ -2061,7 +2061,7 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
>   	/* XXX FIXME: Allocate multi-level tables on PHB3 */
>
>   	/* We shouldn't already have a 32-bit DMA associated */
> -	if (WARN_ON(pe->tce32_seg >= 0))
> +	if (WARN_ON(pe->dma32_seg >= 0))
>   		return;
>
>   	tbl = pnv_pci_table_alloc(phb->hose->node);
> @@ -2070,7 +2070,7 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
>   	pnv_pci_link_table_and_group(phb->hose->node, 0, tbl, &pe->table_group);
>
>   	/* Grab a 32-bit TCE table */
> -	pe->tce32_seg = base;
> +	pe->dma32_seg = base;
>   	pe_info(pe, " Setting up 32-bit TCE table at %08x..%08x\n",
>   		(base << 28), ((base + segs) << 28) - 1);
>
> @@ -2131,8 +2131,8 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
>   	return;
>    fail:
>   	/* XXX Failure: Try to fallback to 64-bit only ? */
> -	if (pe->tce32_seg >= 0)
> -		pe->tce32_seg = -1;
> +	if (pe->dma32_seg >= 0)
> +		pe->dma32_seg = -1;
>   	if (tce_mem)
>   		__free_pages(tce_mem, get_order(TCE32_TABLE_SIZE * segs));
>   	if (tbl) {
> @@ -2520,7 +2520,7 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
>   	int64_t rc;
>
>   	/* We shouldn't already have a 32-bit DMA associated */
> -	if (WARN_ON(pe->tce32_seg >= 0))
> +	if (WARN_ON(pe->dma32_seg >= 0))
>   		return;
>
>   	/* TVE #1 is selected by PCI address bit 59 */
> @@ -2530,7 +2530,7 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
>   			pe->pe_number);
>
>   	/* The PE will reserve all possible 32-bits space */
> -	pe->tce32_seg = 0;
> +	pe->dma32_seg = 0;
>   	pe_info(pe, "Setting up 32-bit TCE table at 0..%08x\n",
>   		phb->ioda.m32_pci_base);
>
> @@ -2547,8 +2547,8 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
>
>   	rc = pnv_pci_ioda2_setup_default_config(pe);
>   	if (rc) {
> -		if (pe->tce32_seg >= 0)
> -			pe->tce32_seg = -1;
> +		if (pe->dma32_seg >= 0)
> +			pe->dma32_seg = -1;
>   		return;
>   	}
>
> @@ -2567,7 +2567,7 @@ static void pnv_ioda_setup_dma(struct pnv_phb *phb)
>   	/* 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.tce32_count, dma_weight);
> +		hose->global_number, phb->ioda.dma32_segcount, dma_weight);
>
>   	pnv_pci_ioda_setup_opal_tce_kill(phb);
>
> @@ -2576,7 +2576,7 @@ static void pnv_ioda_setup_dma(struct pnv_phb *phb)
>   	 * weight
>   	 */
>   	list_for_each_entry(pe, &phb->ioda.pe_dma_list, dma_link) {
> -		if (!pe->dma_weight)
> +		if (!pe->dma32_weight)
>   			continue;
>
>   		/*
> @@ -2587,15 +2587,15 @@ static void pnv_ioda_setup_dma(struct pnv_phb *phb)
>   		if (phb->type == PNV_PHB_IODA1) {
>   			unsigned int segs, base = 0;
>
> -			if (pe->dma_weight <
> -			    dma_weight / phb->ioda.tce32_count)
> +			if (pe->dma32_weight <
> +			    dma_weight / phb->ioda.dma32_segcount)
>   				segs = 1;
>   			else
> -				segs = (pe->dma_weight *
> -					phb->ioda.tce32_count) / dma_weight;
> +				segs = (pe->dma32_weight *
> +					phb->ioda.dma32_segcount) / dma_weight;
>
>   			pe_info(pe, "DMA weight %d, assigned %d DMA32 segments\n",
> -				pe->dma_weight, segs);
> +				pe->dma32_weight, segs);
>   			pnv_pci_ioda_setup_dma_pe(phb, pe, base, segs);
>
>   			base += segs;
> @@ -3314,7 +3314,7 @@ static void __init pnv_pci_init_ioda_phb(struct device_node *np,
>   	mutex_init(&phb->ioda.pe_list_mutex);
>
>   	/* Calculate how many 32-bit TCE segments we have */
> -	phb->ioda.tce32_count = phb->ioda.m32_pci_base >> 28;
> +	phb->ioda.dma32_segcount = phb->ioda.m32_pci_base >> 28;
>
>   #if 0 /* We should really do that ... */
>   	rc = opal_pci_set_phb_mem_window(opal->phb_id,
> diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
> index 38d8616..5ea33ca 100644
> --- a/arch/powerpc/platforms/powernv/pci.h
> +++ b/arch/powerpc/platforms/powernv/pci.h
> @@ -58,15 +58,10 @@ struct pnv_ioda_pe {
>   	unsigned long		m32_segmap[8];
>   	unsigned long		m64_segmap[8];
>
> -	/* "Weight" assigned to the PE for the sake of DMA resource
> -	 * allocations
> -	 */
> -	unsigned int		dma_weight;

This belongs to the previous patch, more precisely to the part of the 
previous patch which changes stuff for PHB3 and which you want to move to a 
separate patch (or to this one, up to you).

> -
>   	/* "Base" iommu table, ie, 4K TCEs, 32-bit DMA */
> -	int			tce32_seg;
> -	int			tce32_segcount;
>   	struct iommu_table_group table_group;
> +	int			dma32_seg;
> +	unsigned int		dma32_weight;

Tiny comment - you not just renamed the fields but also moved them :)

>
>   	/* 64-bit TCE bypass region */
>   	bool			tce_bypass_enabled;
> @@ -182,8 +177,8 @@ struct pnv_phb {
>   			 */
>   			unsigned char		pe_rmap[0x10000];
>
> -			/* 32-bit TCE tables allocation */
> -			unsigned long		tce32_count;
> +			/* Number of 32-bit DMA segments */
> +			unsigned long		dma32_segcount;
>
>   			/* Sorted list of used PE's, sorted at
>   			 * boot for resource allocation purposes
>

-- 
Alexey