Subject: Re: [PATCH v6 09/42] powerpc/powernv: DMA32 cleanup

From: Gavin Shan <[email-masked]>
Date: Tue, 11 Aug 2015 10:19:45 +1000

On Mon, Aug 10, 2015 at 06:07:27PM +1000, Alexey Kardashevskiy wrote:
>On 08/06/2015 02:11 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".
>
>s/dma_weight/dma32_weight/ is ok (does not add much though_ but the rest is
>not. The "tce32_" fields are still TCEs (translation entries) while DMA is a
>process initiated by a device which does not know about how exactly DMA
>addresses are translated later. Since we are on the host side and we actually
>manage TCE tables here, I suggest keeping the "tce32_" prefix for TCE tables
>and memory they use.
>

Ok. Will change accordingly.

>>    * Removed struct pnv_ioda_pe::tce32_segcount.
>
>That's confusing - I had to walk through patches to find out where you
>stopped using it. It would be simpler if you put this particular change to
>
>[PATCH v6 02/42] powerpc/powernv: Drop pnv_ioda_setup_dev_PE()
>
>where you remove dead code.
>

I'll try to reorder the patch...

>
>>
>>Signed-off-by: Gavin Shan <[email-masked]>
>>---
>>  arch/powerpc/platforms/powernv/pci-ioda.c | 48 +++++++++++++++----------------
>>  arch/powerpc/platforms/powernv/pci.h      |  7 ++---
>>  2 files changed, 27 insertions(+), 28 deletions(-)
>>
>>diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
>>index 7342cfd..8456f37 100644
>>--- a/arch/powerpc/platforms/powernv/pci-ioda.c
>>+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>>@@ -917,7 +917,7 @@ 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;
>>  		}
>>@@ -942,14 +942,14 @@ static unsigned int pnv_ioda_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)
>>@@ -1057,7 +1057,7 @@ 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_dma_weight(dev);
>>+		pe->dma32_weight += pnv_ioda_dma_weight(dev);
>>  		if ((pe->flags & PNV_IODA_PE_BUS_ALL) && dev->subordinate)
>>  			pnv_ioda_setup_same_PE(dev->subordinate, pe);
>>  	}
>>@@ -1094,10 +1094,10 @@ static void pnv_ioda_setup_bus_PE(struct pci_bus *bus, bool 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",
>>@@ -1460,7 +1460,7 @@ 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);
>>@@ -1936,7 +1936,7 @@ 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);
>>@@ -1945,7 +1945,7 @@ 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);
>>
>>@@ -2006,8 +2006,8 @@ 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) {
>>@@ -2405,7 +2405,7 @@ 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 */
>>@@ -2415,7 +2415,7 @@ 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);
>>
>>@@ -2432,8 +2432,8 @@ 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;
>>  	}
>>
>>@@ -2452,7 +2452,7 @@ 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);
>>
>>@@ -2461,7 +2461,7 @@ 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;
>>
>>  		/*
>>@@ -2472,15 +2472,15 @@ 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, "DMA32 weight %d, assigned %d segments\n",
>>-				pe->dma_weight, segs);
>>+				pe->dma32_weight, segs);
>>  			pnv_pci_ioda_setup_dma_pe(phb, pe, base, segs);
>>
>>  			base += segs;
>>@@ -3211,7 +3211,7 @@ 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 addd3f7..574fe43 100644
>>--- a/arch/powerpc/platforms/powernv/pci.h
>>+++ b/arch/powerpc/platforms/powernv/pci.h
>>@@ -61,11 +61,10 @@ struct pnv_ioda_pe {
>>  	/* "Weight" assigned to the PE for the sake of DMA resource
>>  	 * allocations
>>  	 */
>>-	unsigned int		dma_weight;
>>+	unsigned int		dma32_weight;
>>
>>  	/* "Base" iommu table, ie, 4K TCEs, 32-bit DMA */
>>-	int			tce32_seg;
>>-	int			tce32_segcount;
>>+	int			dma32_seg;
>>  	struct iommu_table_group table_group;
>>
>>  	/* 64-bit TCE bypass region */
>>@@ -181,7 +180,7 @@ struct pnv_phb {
>>  			unsigned char		pe_rmap[0x10000];
>>
>>  			/* 32-bit TCE tables allocation */
>>-			unsigned long		tce32_count;
>>+			unsigned long		dma32_segcount;
>>
>>  			/* Sorted list of used PE's, sorted at
>>  			 * boot for resource allocation purposes
>>

Thanks,
Gavin